045 ACUS01 KWNS 100042 SWODY1 SPC AC 100040 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Thu Jan 09 2020 Valid 100100Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...01z Update... No changes are warranted to the 20z outlook. Earlier thoughts regarding the evolution of convection tonight remain. Low-level warm advection is currently responsible for a rash of elevated thunderstorms from southeast OK - western AR - southeast MO. This activity is likely driven by eastern branch of LLJ that is oriented from northeast TX into the OH Valley. Later tonight, in response to the approaching trough, a secondary branch of LLJ should strengthen across northwest TX into southwestern OK. Thunderstorm potential will increase along the nose of this feature toward sunrise. Otherwise, isolated thunderstorms are expected near the international border within the base of the digging trough. At this time it appears the threat of severe will increase after the day1 period. ..Darrow.. 01/10/2020 $$  274 ACUS01 KWNS 100550 SWODY1 SPC AC 100549 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Thu Jan 09 2020 Valid 101200Z - 111200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST OKLAHOMA INTO THE ARKLATEX... ...SUMMARY... Severe thunderstorms are expected across the southern Plains into the lower Mississippi Valley. Damaging winds are the greatest severe risk, though tornadoes are possible along with very large hail across the southern Plains. ...Southern Plains/Lower Mississippi Valley... Late-evening water-vapor imagery depicts a well-defined short-wave trough over AZ/northern Mexico, shifting east in line with latest model guidance. This feature is forecast to advance into the southern Rockies by 18z as 90+kt 500mb speed max rotates into the base of the trough south of the Big Bend region. In response to this trough, LLJ is forecast to increase across northwest TX which will enhance low-level warm advection across western OK. Low-level moisture is advancing northwest across OK and should aid buoyancy for elevated convection between 12-14z. Forecast soundings suggest elevated supercells are possible early in the period and this is supported by CAMs with a cluster of convection that will spread northeast across northern OK/southern KS. As this activity spreads east into upper 50s/lower 60s dew points, convection will have an opportunity to become surface based, though discrete cells may not be particularly common as a polar front sags into this region. Farther south, strong boundary-layer heating is expected across west TX where surface-3km lapse rates are forecast to approach 9 C/km. At the same time, strong mid-level height falls will spread across the southern Plains by peak heating, and thunderstorms should easily develop along the eastern edge of this steeper lapse-rate plume. Latest thinking is scattered supercells will evolve from east-central OK - north-central TX - southwestern TX between 19-21z. This activity will be strongly sheared and could produce very large hail early in the convective cycle. With time, multi-scale forcing will encourage an extensive squall line that should race east toward the Arklatex region. Damaging winds will likely be common along this squall line as it advances across eastern OK/east TX during the evening hours. Linear MCS will continue east during the overnight hours, advancing to near the MS River toward the end of the period. While damaging winds should be the primary threat with the squall line, very strong shear and moist profiles will likely result in embedded supercells. A few tornadoes are expected along the QLCS but the lack of confidence in discrete pre-frontal supercells will preclude more than 10% tornado probs during the day1 period. ..Darrow/Nauslar.. 01/10/2020 $$  864 ACUS02 KWNS 100642 SWODY2 SPC AC 100641 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1241 AM CST Fri Jan 10 2020 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHEAST... ...SUMMARY... Severe thunderstorms capable of damaging winds and tornadoes are expected across parts of the southeastern U.S. on Saturday. ...Southeast/Ohio and Tennessee Valleys/Carolinas... At the beginning of the period, an upper-level trough will be located in the southern Plains with a powerful 90 to 110 kt mid-level jet in the Arklatex. At the surface, a low is forecast over the mid Mississippi Valley with a cold front extending southward from the low into southeast Arkansas and central Louisiana. A squall-line should be ongoing at 12Z just ahead of the front with the line moving eastward into the Tennessee Valley and central Gulf Coast by midday. Ahead of the front, forecast soundings during the morning show surface dewpoints in the mid to upper 60s F with MLCAPE around 1000 J/kg. This combined with strong deep-layer shear associated with the mid-level jet, will create conditions favorable for damaging wind gusts along the stronger parts of the line. In addition, an impressive 60 to 80 kt low-level jet should be in place in the lower Mississippi Valley. The low-level shear created by the jet will be favorable for tornadoes along the more organized parts of the line. A potential for strong tornadoes will exist with rotating storms embedded in the line. A strong tornado could also occur ahead of the line if a discrete supercell develops. The squall-line is expected to contain a severe threat through the morning and afternoon, reaching eastern Alabama, far western Georgia and the Florida Panhandle by 00Z/Sunday. The upper-level trough and associated low-level jet will move northeastward across the mid Mississippi Valley in the mid to late afternoon and into the Ohio Valley by early evening. For this reason, the most focused band of large-scale ascent should move northeastward away from the central Gulf Coast states. In response, the northern part of the squall-line may extend as far north as central Kentucky where a marginal wind damage/tornado threat could develop. This threat may extend eastward across the southern Appalachians during the evening, possibly reaching the Carolinas Saturday night. Increasing instability in South Carolina and south-central North Carolina combined with the strong low-level shear may be enough for a marginal wind damage/tornado threat from late evening into the overnight. ...MAXIMUM RISK BY HAZARD... Tornado: 10% SIG - Enhanced Wind: 30% SIG - Enhanced Hail: 15% - Slight ..Broyles.. 01/10/2020 $$  401 ACUS03 KWNS 100811 SWODY3 SPC AC 100810 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0210 AM CST Fri Jan 10 2020 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE EASTERN CAROLINAS... ...SUMMARY... Thunderstorms associated with a marginal wind damage threat will be possible across parts of the eastern Carolinas on Sunday. ...Eastern Carolinas... Southwest mid-level flow will be in place on Sunday along the Eastern Seaboard as an upper-level trough moves quickly northeastward across the Northeast. At the surface, a cold front is forecast to move eastward into the Mid-Atlantic, western Carolinas and central Georgia on Sunday. Ahead of the front, surface dewpoints in the mid to upper 60s F should contribute to some destabilization by midday. MLCAPE is forecast to increase to around 500 J/kg across parts of the eastern Carolinas by afternoon. This combined with increasing low-level convergence along the instability corridor, should result in isolated to scattered thunderstorm development. Although large-scale ascent is forecast to be weak, deep-layer shear should be strong enough for a marginal wind damage threat. The threat should be greatest in far eastern North Carolina where instability is expected to be the strongest. ..Broyles.. 01/10/2020 $$  718 ACUS48 KWNS 100957 SWOD48 SPC AC 100955 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Fri Jan 10 2020 Valid 131200Z - 181200Z ...DISCUSSION... ...Monday/Day 4 and Tuesday/Day 5... The medium-range models are in good agreement on Monday, moving an upper-level trough eastward into the Rockies as southwest mid-level flow remains across the central and eastern U.S. A moist airmass should be in place along the Gulf Coast where isolated thunderstorm development may take place Monday afternoon and evening. The upper-level trough is forecast to move through the central states Monday evening as a low-level jet strengthens in the Southeast. Scattered thunderstorms will be possible along the low-level jet Monday night from the Arklatex and lower Mississippi Valley into the Tennessee Valley. Model consensus suggests that instability combined with strong deep-layer shear, should be sufficient for an isolated severe threat. At this time, predictability is too low to add an area for a greater severe threat. ...Wednesday/Day 6 to Friday/Day 8... The models remain in reasonable agreement on Wednesday, moving an upper-level trough quickly eastward into the mid to upper Mississippi Valley. A moist airmass should be in place across the Gulf Coast states with an axis of low-level moisture extending northward into southern parts of the Ohio Valley. Thunderstorm development will be possible on Wednesday from the central Gulf Coast northward into the Ohio and Tennessee Valleys. Although instability is forecast to be weak, a severe threat could develop in parts of the central Gulf Coast states and Tennessee Valley where surface dewpoints are forecast to be in the mid to upper 60s F and moderate deep-layer shear should be present. From Thursday into Friday, the models move an upper-level ridge across the Southeast but disagree in the central and western states. The ECMWF moves an upper-level trough into the central U.S. while the GFS and Canadian keep the trough in the West. If the ECMWF is close to being correct, then thunderstorms would be possible on Friday in parts of the southern Plains and Arklatex as the upper-level trough passes by. This would be dependent upon a faster upper-level trough. Less potential would exist in a slower scenario with the upper-level trough. At this point, too much uncertainty exists from Wednesday to Friday to add a severe threat area. ..Broyles.. 01/10/2020  879 ACUS11 KWNS 101053 SWOMCD SPC MCD 101053 TNZ000-MSZ000-ARZ000-LAZ000-101300- Mesoscale Discussion 0008 NWS Storm Prediction Center Norman OK 0453 AM CST Fri Jan 10 2020 Areas affected...Central/Eastern AR...Far Northeast LA...Northwest/West-Central MS...Far Southwest TN Concerning...Outlook upgrade Valid 101053Z - 101300Z SUMMARY...An upgrade to Moderate Risk will occur across central/eastern AR, far northeast LA, northwest/west-central MS, and far southwest TN with the upcoming 13Z Convective Outlook. DISCUSSION...Based on recent guidance, the probability for significant wind gusts (i.e. gusts at or above 75 mph) to occur late tonight into early Saturday across northeast LA, central/eastern AR, far southwest TN, and northwest/west-central MS has increased. This increase in probability merits an increase to Moderate Risk, which will occur with the upcoming 13Z Convective Outlook. This expanded Moderate Risk will include Little Rock, AR and Memphis, TN. More details regarding the meteorological conditions will be available within the outlook. ..Mosier/Grams.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MEG...JAN...LZK...SHV... LAT...LON 34709276 35269216 35689086 35498985 34598985 33379028 32299084 32049197 33349269 34709276  969 ACUS11 KWNS 101231 SWOMCD SPC MCD 101230 OKZ000-KSZ000-TXZ000-101330- Mesoscale Discussion 0009 NWS Storm Prediction Center Norman OK 0630 AM CST Fri Jan 10 2020 Areas affected...Western OK...Far South-Central KS Concerning...Severe potential...Watch possible Valid 101230Z - 101330Z Probability of Watch Issuance...40 percent SUMMARY...Elevated thunderstorms capable of producing severe hail may develop across western OK and far south-central KS during the next few hours. Trends will be monitored for possible watch issuance. DISCUSSION...Recent surface analysis places a cold front from just north of WLD (in south-central KS) southwestward into a low over central portions of the eastern TX Panhandle. Low-level moisture continues to return northward/northwestward across OK this morning with surface dewpoints have increasing 2 to 4 deg F over the past 3 hours across much of western OK south of this front. The surface low and front remained largely stationary during that time. However, continued eastward progression of the deep shortwave trough over the Southwest/northern Mexico will promote northeastward development of the surface low along the front. Forcing for ascent near the low (augmented by persistent warm-air advection) amidst the gradually moistening/destabilization air mass will likely lead to thunderstorm development. Cold mid-level temperatures will support moderate instability with any parcels lifted from around 800-900 mb. With the strong vertical shear already in place, these elevated storms may become organized enough to produce severe hail. Trends will be monitored for possible watch issuance. ..Mosier/Grams.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...OUN...DDC...AMA... LAT...LON 36250000 36909935 37219864 37339748 36719725 35689749 34859861 34649982 36250000  827 ACUS01 KWNS 101254 SWODY1 SPC AC 101252 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0652 AM CST Fri Jan 10 2020 Valid 101300Z - 111200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS NORTHEAST TX...SOUTHEAST OK...NORTHERN LA...CENTRAL/SOUTHERN AR... ...SUMMARY... Widespread severe thunderstorms are likely across the southern Great Plains, mainly this afternoon and evening, spreading east into the Lower Mississippi Valley tonight. The most dangerous corridor for strong tornadoes and intense damaging winds should be centered on northeast Texas through northern Louisiana and southern Arkansas this evening through the overnight. ...South-Central States... An outbreak of severe thunderstorms is possible later today through tonight, with the most dangerous portion being tonight into early Saturday morning with a potential derecho and embedded strong tornado risk. Primary changes this outlook are to expand the Moderate Risk east across the Lower MS Valley and increase tornado probabilities for the evening/overnight period. Vigorous shortwave trough near the AZ/NM border will shift east across the southern Great Plains through 12Z Saturday. A powerful 90+ kt jet at 500 mb is expected to emanate out of the base of the trough across east TX/OK. In response to this trough, the LLJ will increase throughout the period, more notably late in the period. Along the northwest periphery of low-level moisture advancement, multiple elevated supercells are expected to develop this morning across parts of western/northern OK into southern KS. A large hail risk is anticipated initially, but convection will have an opportunity to become surface based towards midday, though discrete cells should not be particularly common as a polar front sags into this region. Farther south, strong boundary-layer heating is expected across west TX where 0-3 km lapse rates are forecast to approach 9 C/km. At the same time, strong mid-level height falls will spread across the Pacific cold front/dryline by peak heating, and thunderstorms should easily develop along the eastern edge of this steeper lapse-rate plume. Scattered supercells will evolve from east-central OK to north-central TX by 19-21Z, and farther south into south-central TX during the late afternoon. This activity will be strongly sheared and could produce very large hail early in the convective cycle. With time, multi-scale forcing will encourage consolidation into an extensive QLCS that should accelerate toward the Ark-La-Tex region during the evening. Damaging winds will likely be common along the QLCS with embedded mesovortex and supercell tornadoes. Guidance such as the 00Z HRW-NSSL and HRW-ARW, along with the 06Z NAM and 11Z HRRR suggest that pre-frontal convection should develop out ahead of the QLCS across the Sabine Valley towards 06Z. As this convection spreads northeast across northern LA towards the Ark-La-Miss, the strong tornado potential should increase amid strengthening 0-1 km SRH of 300+ m2/s2 and upper 60s surface dew points. A couple long-track tornadoes are possible given fast storm motions but convective mode should be messy. Consolidation with the accelerating upstream QLCS should eventually occur, sustaining potential for widespread damaging winds with embedded significant severe gusts and tornadoes as it spreads toward the Lower MS Valley through 12Z. ..Grams/Mosier.. 01/10/2020 $$  103 ACUS11 KWNS 101512 SWOMCD SPC MCD 101512 OKZ000-KSZ000-101645- Mesoscale Discussion 0010 NWS Storm Prediction Center Norman OK 0912 AM CST Fri Jan 10 2020 Areas affected...Oklahoma and adjacent portions of south central/southeastern Kansas Concerning...Severe Thunderstorm Watch 1... Valid 101512Z - 101645Z The severe weather threat for Severe Thunderstorm Watch 1 continues. SUMMARY...The risk for supercells capable of producing tornadoes may increase as early as Noon to 2 PM CST, mainly east of the Interstate 35 corridor of Oklahoma, where trends are being monitored for a new severe weather watch. Otherwise, scattered vigorous thunderstorm activity may pose a risk for severe hail across northwestern, central and eastern Oklahoma into southeastern Kansas into early afternoon. DISCUSSION...Mid/upper forcing for ascent, associated with an initial perturbation emerging from larger-scale troughing progressing into the southern Rockies, appears to be contributing to the ongoing increase in thunderstorm activity across Oklahoma and adjacent portions of the southern Plains. Strongest activity has been initially focused above/to the cool side of a quasi-stationary frontal zone now extending across northwestern Oklahoma into southeastern Kansas and the Missouri Ozarks vicinity. However, considerable new thunderstorm development is now underway within the warm sector, across central/southern Oklahoma. Even within the warm sector, storms appear initially rooted above the boundary layer, within a zone of stronger mid-level warm advection (roughly around 700 mb). South of this zone, warmer and more strongly capping elevated mixed-layer air probably will inhibit convective development in the near term. With the northeastward progression of the more favorable large-scale ascent, the warm sector thunderstorm development seems likely to become more focused/shift east of the Interstate 35 corridor of Oklahoma by 17-19Z. As it does, continuing slow surface warming may become increasingly conducive to boundary-layer based storm development, in the presence of strong deep layer shear supportive of supercells. Models suggest that this will also coincided with strengthening south-southwesterly 850 mb flow (up to 50+ kt along an axis across eastern Oklahoma), and associated enlargement of low-level hodographs may become increasingly conducive to tornado development, in addition to a continuing risk for severe hail. ..Kerr.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA...ICT...OUN... LAT...LON 36449933 37439594 36699496 35009470 34149548 34329778 35399889 36449933  642 ACUS01 KWNS 101614 SWODY1 SPC AC 101613 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1013 AM CST Fri Jan 10 2020 Valid 101630Z - 111200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH TONIGHT ACROSS PORTIONS OF NORTHEAST TX...SOUTHEAST OK...NORTHERN LA...CENTRAL/SOUTHERN AR...AND WESTERN MS... ...SUMMARY... Widespread severe thunderstorms are likely across the southern Great Plains, mainly this afternoon and evening, spreading east into the Lower Mississippi Valley tonight. The most dangerous corridor for strong tornadoes and intense damaging winds should be centered on northeast Texas through northern Louisiana and southern Arkansas this evening through the overnight. The ongoing forecast appears to be in good shape, with no changes made for this update. ...OK/KS/MO... Scattered thunderstorms have been occurring this morning over northwest OK. These storms will persist through the day and spread northeastward into parts of southern KS and eventually western MO. Much of this activity appears to be elevated, with the primary risk being hail. ...OK/TX/AR... 12z model solutions are in solid agreement that intense convection will form by mid afternoon roughly along the low-level jet axis across central/eastern OK - building southward into north-central TX. Forecast soundings show very strong vertical shear and sufficient CAPE for a few supercells, along with bowing structures. Damaging winds and tornadoes will be possible with the strongest cells. A strong tornado is possible. Severe storms should spread eastward into western AR after dark. ...TX/AR/LA/MS... By late afternoon, a line of intense storms should develop from northeast into east-central TX. These storms will track eastward into a progressively more sheared and moist environment. Large hail will be the primary threat initially, but storms will quickly evolve into bowing structures with increasing risks of widespread damaging winds and a few tornadoes through the night. Forecast soundings show minimal cap ahead of the line, along with intense low-level shear and ample boundary layer moisture. This suggests the potential for a few discrete storms to form ahead of the squall line as it moves across parts of AR/LA overnight. These storms would have the most prominent threat of strong tornadoes. 12z guidance is consistent in timing the squall line into western MS and southwest TN before Sat/12z, with a continued damaging wind and tornado threat. ..Hart/Gleason.. 01/10/2020 $$  444 ACUS02 KWNS 101727 SWODY2 SPC AC 101726 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Fri Jan 10 2020 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR MISSISSIPPI...ALABAMA...PARTS OF WESTERN TENNESSEE...SOUTHEAST LOUISIANA...AND THE WESTERN FLORIDA PANHANDLE... ...SUMMARY... Severe thunderstorms capable of damaging winds and tornadoes are expected across parts of the southeastern U.S. on Saturday. A risk for damaging wind gusts will include parts of the Ohio Valley and Mid-Atlantic states. ...Synopsis... An intense mid-level shortwave trough will rapidly move from the southern Great Plains to the Lower Great Lakes late Saturday night. In the low levels, a surface low initially over east-central AR will develop northeast towards central IN by early evening and subsequently to the NY Adirondacks by Sunday morning. A warm front will advance northward into parts of the OH Valley and Mid-Atlantic states while a cold front sweeps east across the central Gulf Coast and OH Valley. ...TN/MS/LA/AL/GA/FL Panhandle... A squall line with a risk for severe gusts will be ongoing Saturday morning from near the OH/MS River confluence south-southwestward into coastal LA and the west-central Gulf of Mexico. Intense wind fields associated with a 100-kt 500mb jet and an 80-kt southerly LLJ will gradually shift east/northeastward during the period in association with the progression of the mid-level trough. Strong low-level mass response and associated advection processes will support the poleward transport of lower 60s degrees F dewpoints into middle TN and upper 60s farther south near I-20. Intense background flow fields and associated very large hodographs will support both the threat for severe gusts with bowing segments in the squall line and a conditional risk for tornadoes with any supercell managing to develop ahead of the squall line or with stronger mesovortices. The risk for significant severe gusts will likely focus with more pronounced bowing segments and longer-lived mesovortices. As the squall line advances across AL into GA late in the day, models are indicating less organization in the line as it encounters slightly weaker instability concurrent with the upper system becoming increasingly displaced from the GA/north FL vicinity. ...OH Valley... The northern periphery of the severe risk (damaging gusts and perhaps a brief tornado) will likely extend into the OH Valley associated with the northern part of the squall line expected to develop Friday night into Saturday morning. Intense wind fields coupled with a few hundred J/kg MUCAPE would seemingly support a conditional risk for damaging gusts with a fragmented convective band as far north as OH to the southeast of the forecast surface low track. ...Carolinas north into VA/MD... The latest model guidance shows at least weak instability (MUCAPE ranging from 250 J/kg north to 1000 J/kg south) as flow strengthens during the evening into the overnight. CAM guidance suggests the possibility for a re-invigoration of storms east of the Appalachians as low-middle 60s surface dewpoints infiltrate the Carolina/VA Piedmont. Damaging gusts appear to be the primary risk with this activity during the 04-12z period. ...MAXIMUM RISK BY HAZARD... Tornado: 10% SIG - Enhanced Wind: 30% SIG - Enhanced Hail: 5% - Marginal ..Smith.. 01/10/2020 $$  095 ACUS11 KWNS 101747 SWOMCD SPC MCD 101747 OKZ000-TXZ000-101945- Mesoscale Discussion 0011 NWS Storm Prediction Center Norman OK 1147 AM CST Fri Jan 10 2020 Areas affected...Parts of north central/northeast Texas Concerning...Severe potential...Watch likely Valid 101747Z - 101945Z Probability of Watch Issuance...95 percent SUMMARY...Thunderstorm development across north central and northeast Texas appears increasing likely within the next few hours, accompanied by increasing potential for severe hail and tornadoes as early as 2-3 PM CST. DISCUSSION...In association with the strong gradient between the western Atlantic low-level ridge and troughing across the southern high Plains, southerly 850 mb flow continues to strengthen to 50+ kt along an axis across the Texas coastal plain through northeastern Texas and eastern Oklahoma. This is aiding northward moisture return in a tongue largely east of the Interstate 35 corridor of Texas and Oklahoma. This includes mid 60s surface dew points in a developing corridor from the Corsicana and Waco TX vicinity through Durant and Ardmore OK, which may continue to spread northwestward toward the Dallas-Fort Worth Metroplex, and northward near/west of McAlester OK, through mid to late afternoon. With at least weak boundary layer warming, mixed-layer CAPE to 1500 J/kg is developing, coinciding with the enlarging low-level hodographs, in the presence of strong deep-layer shear. The combination of boundary layer warming and moistening, and weak cooling aloft with increasing large-scale ascent ahead of the approaching mid/upper trough, is contributing to a gradual weakening of mid-level inhibition. Isolated thunderstorm activity may already be initiating near/west of the Metroplex, and latest model output suggests that a more notable increase in storm development is possible near and south of the Red River by around 19Z. Although early activity may be initially rooted in a strengthening low/mid tropospheric warm advection regime, a quick transition to boundary-layer based convection seems probable through 20-21Z. As this occurs, the risk for supercells with the potential to produce tornadoes is expected to increase. Otherwise, stronger storms will pose a risk for severe hail. ..Kerr/Hart.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA...FWD...OUN...SJT... LAT...LON 33929761 34139532 31849622 31499882 33929761  457 ACUS11 KWNS 101812 SWOMCD SPC MCD 101811 MOZ000-KSZ000-OKZ000-102015- Mesoscale Discussion 0012 NWS Storm Prediction Center Norman OK 1211 PM CST Fri Jan 10 2020 Areas affected...Parts of southeastern Kansas and southwestern Missouri Concerning...Severe potential...Watch possible Valid 101811Z - 102015Z Probability of Watch Issuance...60 percent SUMMARY...Potential for supercells capable of producing tornadoes, in addition to severe hail, may increase across southeastern Kansas into southwestern Missouri through 2-4 PM CST. Trends are being monitored for the possibility of a new watch, or extending tornado watch number 2 northward, within the next hour or two. DISCUSSION...Convection with embedded vigorous thunderstorms continues to develop north-northeastward with supporting forcing for large-scale ascent, toward the lower Missouri Valley. Storms may still be largely rooted above the boundary layer, within broader lower/mid tropospheric warm advection. However, weak to modest boundary-layer destabilization is ongoing, ahead of a weak frontal wave which is forecast to migrate across the Chanute KS area toward the Kansas/Missouri state border area (north of Joplin MO) through 20-21Z. With at least some further increase of surface dew points into the lower 60s possible, the environment may become increasingly conducive to supercells accompanied by the risk for tornadoes, in addition to severe hail. ..Kerr/Hart.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SGF...EAX...TSA...TOP...ICT... LAT...LON 38019560 38209382 37919300 36959344 36919418 37049595 38019560  606 ACUS11 KWNS 101855 SWOMCD SPC MCD 101854 IAZ000-MOZ000-KSZ000-NEZ000-110100- Mesoscale Discussion 0013 NWS Storm Prediction Center Norman OK 1254 PM CST Fri Jan 10 2020 Areas affected...Portions of central/eastern KS into far southeastern NE...northwestern MO...and southern IA Concerning...Freezing rain Valid 101854Z - 110100Z SUMMARY...A mix of freezing rain, sleet, and snow will likely occur through the remainder of this afternoon and into the early evening. Freezing rain rates in excess of 0.05 inch per three hours should occur. DISCUSSION...18Z surface analysis shows a shallow arctic cold front advancing south-southeastward across the central Plains. A rapid transition from isolated hail potential to freezing rain concerns exists in a narrow corridor along and behind the front across parts of central/eastern KS into southern IA this afternoon. An area of ongoing precipitation associated with low-level warm advection occurring above the surface cold front should continue shifting northeastward over the next several hours. A pronounced warm nose in roughly the 900-750 mb layer noted on the 12Z sounding from TOP will be slow to erode, and complete melting aloft of frozen hydrometeors should occur initially. Refreezing at the surface will occur behind the cold front as temperatures rapidly fall into the mid to upper 20s. A few surface observations already show this process occurring, with light to moderate freezing rain noted from central KS into northeastern KS, far southeastern NE, and southern IA. Potential exists for freezing rain rates to exceed 0.05 inch per 3 hours in a narrow southwest to northeast corridor across this region through the early evening, with some convective enhancement possible. A gradual transition to sleet and eventually snow appears likely as the warm nose aloft slowly erodes. ..Gleason.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DVN...DMX...EAX...OAX...TOP...ICT...DDC... LAT...LON 37829891 38409851 39879647 40739515 41439369 41749276 41629213 41349199 40879229 40249328 39509447 38419621 37889766 37629837 37829891  148 ACUS11 KWNS 101921 SWOMCD SPC MCD 101921 KSZ000-OKZ000-102015- Mesoscale Discussion 0014 NWS Storm Prediction Center Norman OK 0121 PM CST Fri Jan 10 2020 Areas affected...Portions of northern OK and southern KS Concerning...Severe Thunderstorm Watch 1... Valid 101921Z - 102015Z The severe weather threat for Severe Thunderstorm Watch 1 continues. SUMMARY...An isolated hail threat continues across Severe Thunderstorm Watch 1. Additional watch issuance across this area will probably not be needed, but a local extension in area of Tornado Watch 2 to cover a small part of north-central into central OK is possible. DISCUSSION...Semi-discrete storms across Severe Thunderstorm Watch 1 have evolved into mainly clusters over the past couple of hours as they develop northeastward along and behind an arctic cold front. An isolated hail threat may exist with this activity in the short term. But, messy storm modes and elevated instability quickly decreasing behind the front suggest that the overall severe hail threat should remain quite isolated. Additional Severe Thunderstorm Watch issuance is not expected across this area this afternoon. However, there is some wind and perhaps a tornado threat ahead of the cold front across a small part of north-central into central OK, which is currently just west/north of Tornado Watch 2. Even though low-level winds are slowly veering to southwesterly across this region, a local extension in area of Tornado Watch 2 may be needed given sufficient instability, strong effective bulk shear, and storms occurring across Caddo/Grady counties. ..Gleason.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...OUN... LAT...LON 34709772 34609785 34579837 34689868 34999864 36159827 36929783 37769710 37929674 37989586 37959541 37699517 37289517 37139538 37089620 37019678 36769709 35809769 34709772  681 ACUS11 KWNS 101945 SWOMCD SPC MCD 101944 ARZ000-MOZ000-OKZ000-KSZ000-TXZ000-102115- Mesoscale Discussion 0015 NWS Storm Prediction Center Norman OK 0144 PM CST Fri Jan 10 2020 Areas affected...Parts of central/eastern Oklahoma and adjacent portions of Kansas...Missouri...Arkansas and Texas Concerning...Tornado Watch 2... Valid 101944Z - 102115Z The severe weather threat for Tornado Watch 2 continues. SUMMARY...Upscale growing and organizing convection will pose increasing potential for damaging wind gusts and a few embedded tornadoes through 4-6 PM CST. Potential for more discrete supercells, which could pose a risk for a strong tornado or two, may become maximized near Paris TX, and surrounding areas of southeast Oklahoma/northeast Texas. DISCUSSION...Thunderstorm development has become increasingly widespread, and generally oriented along the 50-55+ kt south-southwesterly 850 mb jet axis across eastern Texas and Oklahoma, which is forecast to continue nosing northward into/across southwestern Missouri through 23-00Z. The extent to which strongest cells to this point have become rooted within the moistening and gradually destabilizing boundary layer remains unclear, but undoubtedly will increase as boundary layer instability peaks late this afternoon and evening. Given the strength of the flow and low-level shear, potential for damaging wind gusts and tornadoes should gradually increase in association with "bowing" segments and developing mesovortices embedded within the organizing convective line. Based on the latest Rapid Refresh forecast soundings, low-level hodographs most conducive to tornadogenesis (including considerable clockwise curvature) in discrete supercells, may become focused around the Paris TX area, by 23-00Z. ..Kerr.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SGF...SHV...TSA...FWD...OUN... LAT...LON 34769649 36599558 37289441 36269411 34079448 32909581 33779695 34769649  034 ACUS01 KWNS 102003 SWODY1 SPC AC 102002 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0202 PM CST Fri Jan 10 2020 Valid 102000Z - 111200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH TONIGHT ACROSS PORTIONS OF NORTHEAST TX...SOUTHEAST OK...NORTHERN LA...CENTRAL/SOUTHERN AR...AND WESTERN MS... ...SUMMARY... Widespread severe thunderstorms are likely across the southern Great Plains, mainly this afternoon and evening, spreading east into the Lower Mississippi Valley tonight. The most dangerous corridor for strong tornadoes and intense damaging winds should be centered on northeast Texas through northern Louisiana and southern Arkansas this evening through the overnight. ...Discussion... Only relatively minor changes were made to the previous convective outlook. Those changes are listed according...1) removal and/or eastward adjustment of severe probabilities over parts of western OK/south-central KS. 2) including the greater St. Louis metro in a categorical slight risk for the possibility of wind damage from squall line activity later this evening. 3) Lowering severe hail probabilities over east-central OK from 30-percent to 15-percent based on ongoing convective trends and the expected gradual shift of the area of most pristine mid-level lapse rates to be farther south into TX. ..Smith.. 01/10/2020 .PREV DISCUSSION... /ISSUED 1013 AM CST Fri Jan 10 2020/ The ongoing forecast appears to be in good shape, with no changes made for this update. ...OK/KS/MO... Scattered thunderstorms have been occurring this morning over northwest OK. These storms will persist through the day and spread northeastward into parts of southern KS and eventually western MO. Much of this activity appears to be elevated, with the primary risk being hail. ...OK/TX/AR... 12z model solutions are in solid agreement that intense convection will form by mid afternoon roughly along the low-level jet axis across central/eastern OK - building southward into north-central TX. Forecast soundings show very strong vertical shear and sufficient CAPE for a few supercells, along with bowing structures. Damaging winds and tornadoes will be possible with the strongest cells. A strong tornado is possible. Severe storms should spread eastward into western AR after dark. ...TX/AR/LA/MS... By late afternoon, a line of intense storms should develop from northeast into east-central TX. These storms will track eastward into a progressively more sheared and moist environment. Large hail will be the primary threat initially, but storms will quickly evolve into bowing structures with increasing risks of widespread damaging winds and a few tornadoes through the night. Forecast soundings show minimal cap ahead of the line, along with intense low-level shear and ample boundary layer moisture. This suggests the potential for a few discrete storms to form ahead of the squall line as it moves across parts of AR/LA overnight. These storms would have the most prominent threat of strong tornadoes. 12z guidance is consistent in timing the squall line into western MS and southwest TN before Sat/12z, with a continued damaging wind and tornado threat. $$  761 ACUS11 KWNS 102053 SWOMCD SPC MCD 102052 TXZ000-102245- Mesoscale Discussion 0016 NWS Storm Prediction Center Norman OK 0252 PM CST Fri Jan 10 2020 Areas affected...Portions of central into south-central TX Concerning...Severe potential...Watch likely Valid 102052Z - 102245Z Probability of Watch Issuance...80 percent SUMMARY...Severe threat is increasing this afternoon. Scattered large hail and perhaps isolated giant hail will be possible, along with strong/damaging winds. A tornado or two may also occur. Watch issuance is likely in the next hour or so (by 22Z / 4 PM CST). DISCUSSION...Strong surface pressure falls around 2.5-3.5 mb in the past two hours are occurring across parts of central TX this afternoon. This is indicative of large-scale ascent associated with a strong mid/upper-level jet overspreading this region. Storms will likely erupt along a pre-frontal confluence zone in the next couple of hours as this pronounced ascent erodes a low-level cap. As this convection moves eastward over parts of central TX and vicinity through the remainder of the afternoon and this evening, it will encounter a moderately to strongly unstable airmass. MLCAPE of 1500-2500 J/kg will likely persist as steep mid-level lapse rates overlie surface dewpoints generally in the lower to mid 60s F. RAP forecast soundings and recent VWPs from KGRK/KEWX show rapid strengthening of the low/mid-level winds, along with some veering. This is supporting 50-60 kt of effective bulk shear, which will be more than sufficient for supercells. Scattered large hail should be the primary severe threat with initial semi-discrete development. Some of this hail could become very large (2+ inches in diameter) given the degree of instability and shear present. Strong to damaging winds may become an increasing concern later this evening as storms eventually congeal into a cluster/line along an eastward-moving cold front. A tornado or two also appears possible, mainly with the initial supercells, although a strong low-level jet and related shear will tend to shift slowly northeastward and away from central TX through the evening. Watch issuance will likely be needed within the next hour or so as storm initiation becomes increasingly probable. ..Gleason/Hart.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CRP...EWX... LAT...LON 28829959 29139979 29679976 30119942 30489893 30909838 30879784 30639739 30309701 29869687 29289698 28879733 28599786 28559843 28599896 28829959  634 ACUS11 KWNS 102059 SWOMCD SPC MCD 102059 TXZ000-OKZ000-102300- Mesoscale Discussion 0017 NWS Storm Prediction Center Norman OK 0259 PM CST Fri Jan 10 2020 Areas affected...Parts of north central and northeast Texas Concerning...Tornado Watch 3... Valid 102059Z - 102300Z The severe weather threat for Tornado Watch 3 continues. SUMMARY...Potential for damaging wind gusts, with some risk for tornadoes, is expected to increase with an evolving convective system overspreading the Dallas-Fort Worth Metroplex between 4 and 6 PM CST. Isolated supercell development may precede the line, and pose a risk for a strong tornado or two, particularly east-northeast of the Metroplex into areas near/west of Paris TX by around 6 PM. DISCUSSION...Thunderstorm development continues to grow upscale and gradually organize across north central Texas into southeastern Oklahoma. This is roughly aligned with the western edge of the 50-55+ kt southerly low-level jet axis. 20Z surface analysis indicates that 2 hourly surface pressure falls are currently maximized in excess of 4 mb, near and just southwest of the Dallas-Fort Worth Metroplex. This appears beneath the southern fringe of stronger difluent and divergent flow aloft (near the inflection between downstream ridging and the approaching short wave trough). Aided by continuing inflow of moist and unstable boundary layer air characterized by CAPE up to 1500 J/kg, in the presence of strong deep layer shear, further upscale growth and organization appears likely. Based on the latest Rapid Refresh, among other model output, the primary convective line probably will surge eastward across the Metroplex during the 4-6 PM CST time frame. Heavy precipitation loading and downward momentum transfer may support primarily an increasing risk for potentially damaging surface gusts, as low-level hodographs tend to become more unidirectional with the approach of the convective line. Largest clockwise-curved low-level hodographs are forecast to remain focused east of the line, where at least isolated discrete supercell development is possible and seems to offer the best potential for tornado development. This may become maximized near/southwest of the Paris TX area by around 6 PM CST. ..Kerr.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SHV...TSA...FWD...OUN... LAT...LON 31859790 32769767 33379719 33859648 34029594 33799522 32419617 31459657 31289728 31859790  164 ACUS11 KWNS 102256 SWOMCD SPC MCD 102255 ARZ000-MOZ000-LAZ000-TXZ000-OKZ000-110100- Mesoscale Discussion 0018 NWS Storm Prediction Center Norman OK 0455 PM CST Fri Jan 10 2020 Areas affected...eastern Oklahoma and northeast Texas...east into southern Missouri...Arkansas...and northwestern Louisiana Concerning...Tornado Watch 2...3... Valid 102255Z - 110100Z The severe weather threat for Tornado Watch 2, 3 continues. SUMMARY...Severe/tornado risk continues across valid portions of Tornado watches 002 and 003, and is increasing to the east, into the Arklatex region. A new watch or watches will be required. DISCUSSION...The latest surface analysis depicts a weak low/frontal wave over the north-central Texas/far south-central Oklahoma area, along a baroclinic zone extending from central Missouri southwestward across the eastern half of Oklahoma, and then south-southwestward across central Texas. Thunderstorms are currently evolving linearly along the cold-frontal portion of the boundary across Texas, with a well-developed supercell noted within the band southwest of the DFW Metroplex, moving north-northeast at 45kt. Farther northeast, across the eastern Oklahoma/northwestern Arkansas vicinity, a couple of bowing clusters of storms are moving quickly northeastward in the vicinity of the warm-frontal portion of the baroclinic zone, where damaging wind risk is evident. Meanwhile, a warm/moist/unstable -- but slightly capped -- warm sector is indicated ahead of the line, across east Texas and the Arklatex region. Storms have been slow to organize across this area ahead of the frontal band of cells, but -- aided by a very favorably-sheared environment -- a recent supercell has evolved in the Corsicana vicinity, which remains capable of producing severe weather including tornado potential. With time, the frontal band of storms will continue moving eastward, posing mainly a damaging wind risk, though with some tornado potential with embedded rotating updrafts within the band. Ahead of the line, warm-sector storms are forecast to gradually increase in coverage/organization -- and these more isolated cells will likely be accompanied by greater risk for tornadoes, in addition to wind-damage potential. As this risk evolves over the next couple of hours, and as bowing storms farther north continue to advance northeastward, convection/severe risk will begin to impinge on eastern fringes of WW 002 and 003. This will require new/downstream issuance of an additional Tornado Watch or two, to cover the eastward-advancing risk through much of the evening. ..Goss.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...MEG...JAN...LSX...LZK...SGF...SHV...TSA... HGX...FWD...OUN...EWX... LAT...LON 30959592 30889738 31159835 33179749 34619625 35619443 36819386 37659169 37509075 36119043 33559132 31609285 30959592  962 ACUS11 KWNS 102340 SWOMCD SPC MCD 102340 WIZ000-ILZ000-IAZ000-110545- Mesoscale Discussion 0019 NWS Storm Prediction Center Norman OK 0540 PM CST Fri Jan 10 2020 Areas affected...eastern Iowa...southern Wisconsin...far northwest Illinois Concerning...Winter mixed precipitation Valid 102340Z - 110545Z SUMMARY...Freezing rain, sleet, and snow are all likely from eastern Iowa into southern Wisconsin this evening and tonight. Precipitation will diminish from southwest to northeast tonight/overnight. DISCUSSION...A strong upper-level trough is ejecting out over the Plains with an associated surface front oriented southwest-northeast from central Oklahoma through Lower Michigan. Winter mixed precipitation continues across northern Missouri, southern/eastern Iowa and into southern Wisconsin. As the surface low tracks/develops east-northeast across the southern Plains and into Mississippi Valley, the surface front will slide south/east across southeast Iowa, southern Wisconsin, and northwest Illinois. Along and behind the surface front, freezing rain/sleet are likely before transitioning to snow in a fairly narrow corridor. Strong isentropic ascent via warm air advection and low/mid-level frontogenesis will provide enough lifting for freezing rain rates to likely exceed 0.05 inches per 3 hours, and snowfall rates up to 1-2 inches per hour across portions of this area. Sleet will also occur at the interface of the freezing rain/snow transition, which is already evident per dual-pol correlation coefficient values via KDMX and KDVN. Precipitation will continue through 06z, but will decrease from southwest to northeast across eastern Nebraska, northern Missouri, and southern/eastern Iowa. ..Nauslar/Edwards.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX...DMX... DMX... LAT...LON 41019194 40829255 41069297 41409316 41939318 42639228 43299114 43808955 43898821 43778770 43298757 43088795 42538899 42019011 41409114 41019194 43179062 43608913 43678819 43638773 43418783 43238822 42928904 42459033 41999127 41589194 41039284 41199306 41529310 42009285 42749167 43179062  683 ACUS11 KWNS 102350 SWOMCD SPC MCD 102350 COR WIZ000-ILZ000-IAZ000-110545- Mesoscale Discussion 0019 NWS Storm Prediction Center Norman OK 0550 PM CST Fri Jan 10 2020 Areas affected...eastern Iowa...southern Wisconsin...far northwest Illinois Concerning...Winter mixed precipitation Valid 102350Z - 110545Z CORRECTED FOR GRAPHIC SUMMARY...Freezing rain, sleet, and snow are all likely from eastern Iowa into southern Wisconsin this evening and tonight. Precipitation will diminish from southwest to northeast tonight/overnight. DISCUSSION...A strong upper-level trough is ejecting out over the Plains with an associated surface front oriented southwest-northeast from central Oklahoma through Lower Michigan. Winter mixed precipitation continues across northern Missouri, southern/eastern Iowa and into southern Wisconsin. As the surface low tracks/develops east-northeast across the southern Plains and into Mississippi Valley, the surface front will slide south/east across southeast Iowa, southern Wisconsin, and northwest Illinois. Along and behind the surface front, freezing rain/sleet are likely before transitioning to snow in a fairly narrow corridor. Strong isentropic ascent via warm air advection and low/mid-level frontogenesis will provide enough lifting for freezing rain rates to likely exceed 0.05 inches per 3 hours, and snowfall rates up to 1-2 inches per hour across portions of this area. Sleet will also occur at the interface of the freezing rain/snow transition, which is already evident per dual-pol correlation coefficient values via KDMX and KDVN. Precipitation will continue through 06z, but will decrease from southwest to northeast across eastern Nebraska, northern Missouri, and southern/eastern Iowa. ..Nauslar/Edwards.. 01/10/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX...DMX... LAT...LON 41019194 40829255 41069297 41409316 41939318 42639228 43299114 43808955 43898821 43778770 43298757 43088795 42538899 42019011 41409114 41019194