Severe Storms

No watches are valid as of Wed Mar 16 14:22:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0743 AM CDT Wed Mar 16 2022 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL FLORIDA TO PARTS OF SOUTH CAROLINA... ...SUMMARY... Isolated severe thunderstorms will be possible across parts of the Southeast today. Large hail should be the main threat, with marginal potential for damaging gusts or a tornado. ...Synopsis... In mid/upper levels, a progressive pattern over the CONUS features three primary, convectively influential perturbations: 1. A closed cyclone, initially centered over the MS/AL border area, along a height trough extending from central KY to the central Gulf. The low and trough are forecast to weaken slightly -- but still maintain a closed circulation, while moving east-northeastward across the Southeast through the period. By 12Z tomorrow, the 500-mb low should be located near CLT, with trough southward across SC and just offshore GA. 2. A southern-stream shortwave trough initially evident in moisture-channel imagery over portions of NV/CA. This feature should amplify and move east-southeastward across the Great Basin today. Associated DCVA/destabilization and cooling aloft will combine with diurnally warmed boundary layers to support isolated thunderstorm potential over parts of the Great Basin and Four Corners region. 3. A northern-stream perturbation -- currently located over the interior Pacific Northwest. This feature also should amplify and move east-southeastward through the period. Some phasing with the southern-stream trough may occur late tonight. In the meantime, associated steepening of low/middle-level lapse rates will spread across parts of MT, with weak but sufficient low/middle-level moisture to support isolated thunderstorms. At the surface, 11Z analysis showed a broad, poorly defined low-level cyclone centered near SEM. An occluded front arched from the low across southeastern AL, to a triple point estimated between TLH-PFN. A cold front extended from there southward then southwestward over the eastern and central Gulf. A warm front was drawn across northern FL, and was poorly defined over land with residual/rain-cooled air on both sides. The front was sharper across coastal waters of GA, to just offshore from SC and southeastern NC. The warm front will move northward across southern/central portions of both GA/SC today, perhaps into extreme southern NC tonight. An outflow boundary from previous night's activity lingers quasistationary over central FL, and should drift northward through the afternoon. By 00Z, the broad low-level cyclone will cover much of AL/GA, tilting slightly northward with height into the midlevels. The cold front should extend across south-central GA, north-central/west- central FL, and the eastern/south-central Gulf. The area of surface low pressure may consolidate somewhat over the eastern NC tonight, with the 12Z frontal position from there southward over Atlantic waters across parts of south FL. ...Southeast... Isolated to scattered thunderstorms are expected to form today ahead of the surface cold front, in a broadly arc-shaped corridor from south-central/central FL across the JAX/SAV areas near the Atlantic Coast, to portions of eastern GA and southern/central SC. The main concern will be large hail, especially from any supercells that develop, with isolated damaging gusts and a tornado or two also possible. Without substantial/ongoing convection across much of the region, especially across the FL Peninsula, ample diabatic destabilization is expected by early/mid afternoon, in a suitably moist environment with shear favorable for a few supercells. Significant (2+ inch diameter) hail also may occur in central FL, given: 1. Enough deep shear for supercells (effective-shear magnitudes around 40-45 kt) -- especially near the remnant outflow boundary -- supporting potential for sustained, storm-scale rotation to augment updraft intensity; 2. Ample inflow-layer water content to foster hail growth, with surface dew points commonly in the mid 60s to low 70s F by expected storm-maturation time in early/mid afternoon; 3. A "top-heavy" buoyant profile well into favorable ice-growth layers, with diabatic heating and aforementioned moisture beneath steep midlevel lapse rates (leading to MLCAPE around 1500 J/kg, locally near 2000 J/kg); 4. The appearance of a few historic analogs for significant hail in several forecast soundings in the area. The main remaining question is the extent supercells can remain relatively discrete long enough to produce very large hail. Still, given the favorable environment, a 10%/hatched "sig-hail" area has been introduced. Isolated, marginal severe potential will extend westward from the northern part of the 15% hail area across GA and parts of AL, deeper into the midlevel core region of the mid/upper cyclone. In those areas, the coldest air aloft will be present, but with weak winds aloft limiting vertical shear. Isolated severe also may occur from predominantly multicellular thunderstorms southward over parts of south FL, where favorable moisture/buoyancy will be present, but with weaker low-level flow, smaller hodographs and less low-level shear than over central parts of the peninsula. Marginal severe potential also may develop this afternoon through tonight over parts of southern/eastern NC, but with modest instability aloft (MUCAPE around 300-800 J/kg) and weak low-level lapse rates as limiting factors. ..Edwards/Kerr.. 03/16/2022 Read more

No Mesoscale Discussions are in effect as of Tue Mar 15 14:03:02 UTC 2022.

No watches are valid as of Tue Mar 15 14:03:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Tue Mar 15 2022 Valid 151300Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TONIGHT IN CENTRAL FLORIDA... ...SUMMARY... Isolated strong to damaging thunderstorm winds and a marginal tornado threat exist today over the central Gulf Coast. A somewhat greater potential for severe wind exists tonight over central Florida. ...Synopsis... A progressive, split-flow pattern will dominate the mid/upper troposphere today across the CONUS. The source of the split is a closed cyclone -- apparent in moisture-channel imagery over the Arklatex region -- with trough extending southwestward to deep south TX. The trough will become more neutrally tilted through 12Z tomorrow, as the parent cyclone moves slowly eastward across MS. At the surface, 11Z analysis showed a low along the north portion of a convective band, over southeastern LA. A separate weak low was evident over central LA, with cold front extending southwestward past Sabine Pass to near BRO. The cold front will proceed eastward/southeastward across the north-central and northeastern Gulf through the period, preceded by convective complexes/ boundaries, while an accompanying broad/weak area of low pressure moves roughly along the coast, or just inland. Warm frontogenesis is expected this evening over south-central FL, shifting northward across central FL just ahead of a convective arc or complex moving inland from the Gulf. ...Central Gulf Coast to FL... A band of thunderstorms over extreme southeastern LA and southern MS, into the north-central Gulf, will pose a threat for damaging/ isolated severe gusts and perhaps a tornado in the next few hours as it moves eastward over the MS/AL coastal areas and parts of the FL Panhandle. Though the most intense activity should remain over Gulf waters where low-level instability/lapse rates are greatest, isolated surface-based effective-inflow parcels and associated severe potential may extend into coastal areas. As the mid/upper trough and low move eastward, associated height falls and mesoscale shots of midlevel DCVA (some of it convectively generated/enhanced) will spread over the outlook area from west to east, along with weakly destabilizing influences of low-level warm advection. Meanwhile, a considerably more-unstable boundary layer will underlie these regimes over the Loop Current in the open northeast Gulf, supporting severe convection there. This activity should move eastward and affect the FL Peninsula tonight, perhaps preceded by (or merging with) late-afternoon/early-evening thunderstorms developing on the remnant sea breeze boundary. Before this activity approaches the west-central coast of FL, moist advection in and south of the diffuse warm-frontogenetic zone will boost surface dew points into the mid-upper 60s F inland, to around 70 along the western coastline. Forecast soundings indicate MLCAPE increasing into the 500-1500 J/kg range (generally decreasing northward over land). Low-level and deep shear will be maximized in the warm- frontal zone (e.g., up to about 200 J/kg effective SRH and 40-45-kt effective-shear magnitudes). This will support organized convective structures, including line-embedded supercells and/or bowing segments, as well as the potential for a supercell or two preceding the main MCS. As the convection moving off the Gulf interacts with this environment and boundaries therein, severe potential should relatively maximize -- especially convective wind, for which probabilities have been increased by one level. At least marginal tornado threat also exists (especially in and near the warm frontal zone), though lack of stronger low-level flow will limit size of the favorably curved hodographs somewhat. ..Edwards.. 03/15/2022 Read more

No watches are valid as of Mon Mar 14 13:57:02 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Mar 14 13:57:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 AM CDT Mon Mar 14 2022 Valid 141300Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH-CENTRAL/NORTHEAST TEXAS...SOUTHEASTERN OKLAHOMA...SOUTHWESTERN ARKANSAS...AND WESTERN LOUISIANA... ...SUMMARY... Thunderstorms may produce large to very large hail, isolated wind damage, and a tornado or two across parts of north-central/northeast Texas, southeastern Oklahoma, southwestern Arkansas, and western Louisiana. ...Synopsis... The main mid/upper-level feature for this outlook will be a strong shortwave trough -- now apparent in moisture-channel imagery over parts of CO/NM to far west TX. This trough should dig southeastward through the day, with a closed 500-mb low forming by this evening over central/southern OK. By the end of the period, that low should be located over the TXK/SHV area, with trough southwestward to deep south TX. An associated surface low was drawn at 11Z near DDC, with cold front trailing across the TX Panhandle and into adjoining parts of NM. By 00Z, an elongated area of low pressure should exist along the front from central OK across north TX, with the front trailing south- southwestward to between DRT-LRD. By 12Z, the surface low should consolidate over east-central/northeast TX not far south of the mid/upper low, with cold front arching roughly southward over the Sabine River region and the northwestern Gulf. A weak warm front should develop this evening from northeast TX southeastward over coastal south-central/southeastern LA with the approach of the mid/upper perturbation, and move slowly northeastward. ...North-central/southeast TX, southern OK, southwest AR, LA... Scattered thunderstorms from late afternoon through tonight will offer the threat for large to significant/2+ inch hail, occasional severe gusts, and a tornado or two. The main area of convection is expected to form late this afternoon to around 00Z near the cold front -- close to the I-35 corridor from central/southern OK across north-central/central TX. The gradient in severe potential extends across the DFW Metroplex, with the threat increasing eastward. Though the outlook probabilities have been tightened some, enough mesoscale uncertainties linger to avoid getting more spatially specific at this time. Another area of convection may develop this evening over east TX, in the warm sector. A blend of supercells and multicells are possible in both regimes, with some discrete cells relatively early in the convective cycle offering the greatest hail/tornado threats. This should occur as: 1. The front impinges on incompletely modified -- yet unstable and increasingly moist -- return-flow air, and 2. Strengthening large-scale ascent overspreads the warm sector from northwest-southeast, with considerable weakening of EML-related capping evident in 12Z DRT/FWD/OUN soundings. The continuing Gulf boundary-layer modification process, and northward-directed moist advection from there, should result in surface dew points in the 50s F by 00Z into parts of south-central/southeastern OK and north TX, with low 60s possible into parts of east TX. With strong cooling aloft and steepening of low/middle-level lapse rates, forecast soundings over north and east TX develop a "top-heavy" CAPE profile with MLCAPE peaking in the 1000-1500 J/kg range. Bulk shear will strengthen with southward extent from southern OK into central TX, nearer the mid/upper speed max curving around the trough. Effective-shear magnitudes near the main convective arc should range from around 25-30 kt in southern OK, where mid/upper flow will be relatively weak, to 45-50 kt over the CLL area later this evening. Well-curved low-level hodographs with effective SRH in the 150-300 J/kg range should be common across north and east TX. At least marginally favorable CAPE/shear parameter spaces may spread inland over southern LA late tonight near and south of the warm front, supporting a conditional potential for parts of the MCS to continue eastward into coastal southeast TX and LA, with locally strong/damaging gusts and marginal tornado threat. ..Edwards/Kerr.. 03/14/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1019 AM CST Fri Mar 11 2022 Valid 111630Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TONIGHT OVER PORTIONS OF THE NORTHERN FLORIDA AND SOUTHERN GEORGIA.... ...SUMMARY... Damaging wind and a few tornadoes are possible across the central and northeastern Gulf Coast to the Carolinas and northern Florida. The period of greatest concern appears to be late tonight into Saturday morning. ...Southeast States... Only minor changes have been made to the ongoing forecast. Water vapor imagery shows a strong upper trough digging southeastward across NM. This feature is forecast to rotate into the lower MS valley tonight. Large scale lift and strengthening wind fields ahead of the trough will result in a large area of increasing severe threat - mainly after dark. A large and persistent band of thunderstorms extends across the northeast Gulf of Mexico into north FL. This convection has significantly modified the air mass over the region, and is limiting the northward return of rich Gulf moisture. Most models substantially weaken the activity by late afternoon allowing rapid return of 70s dewpoints into parts of southern GA and the northern FL. While this scenario remains quite possible, confidence in how far north the tropical air mass can return is in question. Will not adjust the ENH risk area at this time and defer to later updates. Otherwise, it appears the main severe risk will develop over southern LA/MS after dark as the upper wave approaches. This activity will spread eastward along the Gulf coast and into the ENH risk area after midnight. Forecast soundings suggest low-level shear will strengthen through the night ahead of the cold front, with a risk of supercells and tornadoes in those areas where the rich Gulf moisture can return. Farther north, across parts of GA and the Carolinas, bowing structures capable of damaging winds and isolated tornadoes appear to be the main threat. ..Hart/Weinman.. 03/11/2022 Read more

No watches are valid as of Fri Mar 11 16:23:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Mar 11 16:23:02 UTC 2022.

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0950 AM CST Fri Mar 11 2022 Valid 111700Z - 121200Z ...NO CRITICAL AREAS... Fire weather concerns remain low for today. A cold front continues to push south/southeast towards the Gulf Coast and lower Mississippi River Valley with bands of snow ongoing across portions of northwest TX and west OK where drought conditions are most pronounced. Areas of the southern Plains that have not received precipitation over the past 24 hours are experiencing well below seasonal temperatures, which will further mitigate fire weather potential. A -4 mb DAG-LAX pressure gradient is driving wind gusts between 35-50 mph within the higher terrain along the southern CA coast. A few locations are experiencing elevated to critical wind/RH conditions, but regional ERCs remain too low to support a substantial fire weather risk. Winds are expected to gradually abate through the day and into the evening hours. ..Moore.. 03/11/2022 .PREV DISCUSSION... /ISSUED 1240 AM CST Fri Mar 11 2022/ ...Synopsis... A broad upper-level trough will continue to shift east and intensify today. At the surface, a strong cold front will push south and east through the Plains and into the lower Mississippi Valley. High pressure will remain in the Great Basin and build into a large portion of the country east of the Divide. Fire weather concerns will be relatively low during the period. Strong offshore winds are still expected through mid morning in southern California. Live fuel moisture remains high enough to limit fire weather concerns. Pockets of dry and windy conditions are also possible behind the cold front in the Plains and the Southwest. Between limited spatial coverage and poorly receptive fuels, concerns will similarly be mitigated in these areas as well. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0656 AM CST Fri Mar 11 2022 Valid 111300Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY TONIGHT OVER PARTS OF THE EASTERN FLORIDA PANHANDLE...NORTHWESTERN FLORIDA AND SOUTHERN GEORGIA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ELSEWHERE FROM THE CENTRAL GULF COAST AND NORTHERN FLORIDA TO THE CENTRAL CAROLINAS...AND VERY LATE TONIGHT OVER EASTERN NORTH CAROLINA... ...SUMMARY... Damaging wind, isolated hail, and a few tornadoes are possible across the central and northeastern Gulf Coast to the Carolinas and northern Florida. Isolated severe thunderstorms are possible during the day, but the greatest threat appears to be late tonight into Saturday morning. ...Synopsis... A major trough is evident over central/southwestern North America at this time, from a cyclone north of Hudson Bay across the Upper Midwest, central Plains, Desert Southwest, and northern Baja. Two primary shortwave troughs will become increasingly phased through the period, contributing to the eastward progression of the larger-scale, positively tilted trough: 1. A southern-stream perturbation apparent in moisture-channel imagery over parts of southwestern CO, eastern AZ, Sonora, and northern Baja. This feature should pivot eastward across NM today, reaching OK, west TX and northern Chihuahua by 00Z. By 12Z, it should merge with the amplified southern part of the feature below, and reach the Mid-South and LA. 2. A northern-stream shortwave trough, currently over the MN/ON Boundary Waters region, southwestward to SD. This perturbation is expected to swivel to a less-positive tilt, and amplify, extending from Lake Superior across WI/IA by 00Z. BY 12Z, this shortwave trough should extend from northeastern ON to southern IL. and blend with the southern-stream trough above, to form a progressive synoptic-scale trough that will sweep eastward across the eastern CONUS on day 2. At the surface, 11Z analysis showed a synoptic cold front-over northwestern OH, southern IN, central AR, through a weak frontal- wave low over northeast TX, then arching across east-central/south- central TX to northern Coahuila. This front is forecast to intensify as the upper trough coalesces and moves eastward. By 00Z, the front should extend across western portions of NY/PA, southwestward over eastern TN and northern AL, to a developing frontal-wave low over the southeastern MS/southern AL area, then southwestward over the northwestern Gulf. That low is expected to move rapidly northeastward tonight, reaching northern NC or southeastern VA by 12Z tomorrow, with the cold front across the eastern Carolinas, southeastern GA, the FL coastal bend, and northeastern through southwestern Gulf. A quasistationary frontal zone was drawn across extreme southern GA and the western FL Panhandle, north of a series of aggregated outflow boundaries from north-central FL to the northeastern/north-central Gulf. These FL/GA boundaries may become more diffuse later today and especially overnight, amidst a broad, rapidly intensifying, low-level, warm-advection regime. ...Southeastern CONUS... A complex severe-thunderstorm event with multiple rounds of activity appears probable for the day-1 period, and will carry over past 12Z into day 2 over eastern parts of the region. Some geographic displacements and overlaps are likely between these convective regimes, but enough mesoscale uncertainty lingers at this update cycle not to get overly precise in introducing additional gaps or holes to the severe-threat areas. The most spatial overlap still appears to be over the eastern FL Panhandle/coastal bend, northwestern FL and southern GA, where the cumulative of several rounds of strong-severe thunderstorms yields the greatest total full-period threat. Broadly speaking, the potential episodes are as follows, in chronological order: 1. Northeast Gulf to northern FL today: Multiple clusters of thunderstorms will form over the Gulf today and move eastward to east-northeastward across the region -- a few strong-severe with isolated supercells and organized multicells. Severe weather should be isolated and sporadic, with damaging gusts, occasional hail, and a couple tornadoes all possible. The most favorable inflow-layer air mass will be along its eastern and southern rim, with diurnally heated destabilization of the boundary layer over northern FL ahead of ongoing convection, and optimized surface theta-e over the northeastern Gulf. Despite potential for baroclinic reinforcement by convective outflow, strengthening ambient southwesterlies through much of the troposphere, as the supper trough approaches, may contribute to a northward shift of the convective boundary this afternoon into this evening, behind the ongoing activity. 1000-1500 J/kg MLCAPE over northern FL along and south of the older boundary, along with 35-45 kt effective-shear magnitudes, will support some convective organization. 2. Southeastern parts of LA/MS to GA and Carolinas tonight: This should become the main episode in terms of severe potential over the longest area. Scattered thunderstorms are expected to form along/ahead of the cold front, initially this evening in the corridor from southeastern LA to southern AL, expanding both northeastward and southwestward with time as the entire regime shifts east. Convection should be mainly in quasi-linear and clustered modes, but with a few discrete supercells possible. This activity will sweep rapidly northeastward, offering damaging to severe gusts and the potential for a few tornadoes. Given the rapidly intensifying flow in midlevels, and in low levels above the surface, vertical shear will increase substantially and region-wide overnight. A swath of more-concentrated damaging-wind potential may develop across parts of southeastern AL, western/ central GA, western/central SC and central NC late tonight, under the fast-moving convection. However, uncertainties regarding destabilization well inland -- north of the persistent convective plume over the northeastern Gulf -- preclude boosting the unconditional probabilities north of the existing "Enhanced" area at this time. Forecast soundings suggest a slightly stable to neutral near-surface layer that may mitigate downdraft momentum transfer with severe wind somewhat -- but not eliminate it. The southern part of this convective regime also should backbuild over the Gulf and overtake the next one late tonight, likely from about 09Z onward. 3. Northeast Gulf to northern FL/southern GA tonight: Whether or not a respite develops between the daytime event over this region and the overnight convection (progs are rather inconsistent in that regard), the same plume of low-level lift should support more thunderstorms overnight. As the western part of this is overtaken by the prefrontal band tonight, severe potential may maximize over the Enhanced area, with tornadoes and damaging gusts the main concerns. Strengthening low-level mass response is expected in the form of warm advection and moisture transport, contributing to at least marginal low-level destabilization, despite the longstanding presence of an antecedent convective boundary over the northeastern Gulf. Any relative gaps would permit even more destabilization inland. 3. Eastern NC, after 09Z: Thunderstorms may move northward to northeastward across this region just before the end of the period, in a plume of increasing low- level lift and theta-e from adjoining Atlantic waters to the south. Low-level and deep shear also will be strengthening rapidly during this time frame, as a LLJ increases from the 40-60-kt range at 06Z to at least 70-80 kt by 12Z. Thunderstorm coverage remains uncertain, since instability will be weak (with MLCAPE 200-500 J/kg), and convective-scale forcing will be subtle in a regime well-displaced from the primary frontal/convective boundaries. Still, any sustained thunderstorms in this environment will pose a threat for damaging gusts and tornadoes, given 50-60 kt effective- shear magnitudes, 0-1-km shear around 30-45 kt, and enlarging hodographs with time. ..Edwards/Kerr.. 03/11/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0918 AM CST Thu Mar 10 2022 Valid 101700Z - 111200Z Shifted the risk area into southeast Arizona and trimmed the eastern extent of the elevated area based on morning frontal position and expected eastward movement of the front/dryline this afternoon. ..Bentley.. 03/10/2022 .PREV DISCUSSION... /ISSUED 1247 AM CST Thu Mar 10 2022/ ...Synopsis... An amplifying mid-level trough, embedded in the larger scale cyclonic upper flow regime, will impinge on the southern Rockies today, supporting surface low development across central New Mexico, and encouraging dry and windy conditions across southern New Mexico into far west Texas. Elevated highlights have been introduced where 15-25 mph sustained west-southwesterly surface winds will coincide with 10-20 percent RH through the mid to late afternoon hours. While Critical meteorological conditions will most likely develop across southwestern into central New Mexico, forecast ERCs are expected to reach the 60th-70th percentiles, suggesting that fuels may not be quite dry enough to support a widespread, robust wildfire-spread threat. Fuels are drier near the Trans Pecos, where forecast ERCs may reach the 80th-90th percentiles. However, westerly surface winds may sustain only in the 15-20 mph range, which is below Critical criteria. Nonetheless, the modest fuel receptiveness and dry/windy conditions should foster high-end Elevated conditions through the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Thu Mar 10 15:21:02 UTC 2022.

No Mesoscale Discussions are in effect as of Thu Mar 10 15:21:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0641 AM CST Thu Mar 10 2022 Valid 101300Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL AND NORTHERN FLORIDA... ...SUMMARY... Isolated damaging thunderstorm winds are possible over parts of central and northern Florida. ...Synopsis... Broadly cyclonic mid/upper-level flow, around a substantial longwave trough, will cover much of the CONUS through the period. An extensive fetch of west-southwest to southwest flow aloft will cover the Southeast -- ahead of a strengthening, positively tilted shortwave trough digging southeastward over the Great Basin, Four Corners and parts of AZ/NM. In that flow belt, a leading, low- amplitude shortwave trough -- evident in moisture-channel imagery over MS -- will weaken and eject northeastward to near the Delmarva Peninsula by 00Z, then out to the Atlantic thereafter. Surface analysis at 11Z showed a quasistationary, synoptic frontal zone over southern portions of SC/GA, southwestward across the AAF area and the north-central Gulf. This front will drift erratically on the mesoscale but exhibit no substantial motion through the period, bring beneath nearly parallel flow aloft. To its south, an outflow boundary was drawn across the FL Peninsula near a DAB-LEE- PIE line, also quasistationary. This boundary generally should move/redevelop erratically northward today and tonight, once the associated swath of convection and precip along and just to its north weakens and moves eastward to the Atlantic. A more-distant synoptic cold front was drawn from southern ON to southern portions of IL/MO, northern/western OK, through a weak frontal wave over northwest TX, to southeastern and north-central NM. This boundary will sag slowly southward through the period, reaching the lower Ohio Valley, central AR, the Edwards Plateau, and far west TX by 12Z tomorrow. ...FL... Widely scattered to scattered thunderstorms should both move eastward off the Gulf, and develop over the peninsula, during the day. This will occur as the inland boundary layer destabilizes today along and south of the outflow boundary. Organized multicells in bands and clusters, and perhaps isolated/transient supercells, are possible. Isolated damaging gusts will be the main concern, and large hail may occur in the most intense cores as well, even north of the boundary along the Gulf Coast of the eastern Panhandle to the coastal bend. Tornado potential is non-zero but very conditional on localized, mesobeta- to storm-scale processes and storm/boundary interactions, given the modest ambient low-level hodographs/shear values progged. Though the leading shortwave trough will pass well poleward of the outflow boundary over FL, subtle tightening of midtropospheric height gradients related to the shortwave trough, and associated low/middle-level mass response, should extend far enough south to influence organized convective potential today. Effective-shear magnitudes around 40-45 kt should be common (locally/briefly higher). Where sufficient diurnal surface heating can occur into the afternoon, behind morning clouds/precip, surface dew points from the upper 60s to low 70s F may support MLCAPE in the 1500-2000 J/kg range. During the evening, boundary-layer stabilization and decreasing deep-layer flow both are expected, resulting in reduced convective coverage and dwindling of severe potential over the bulk of the peninsula. A separate round of thunderstorms -- developing tonight over the north-central/northeastern Gulf and predominantly affecting the inland parts of the region on day 2 -- may reach coastal portions of the central/eastern FL Panhandle during the last few hours of the period (i.e., 09-12Z). At this time, forecast low-level thermodynamic profiles appear too stable for surface-based convection before 12Z, and unconditional severe wind and tornado potential appears too minimal to stretch those outlook lines westward toward the AAF area. ..Edwards/Mosier.. 03/10/2022 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Wed Mar 09 2022 Valid 092000Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH EARLY EVENING ACROSS NORTHERN FLORIDA INTO EASTERN SOUTH CAROLINA... ...SUMMARY... A few damaging wind gusts and isolated hail are possible through early evening from north Florida into eastern South Carolina. ...20z Update -- FL/GA/Carolinas... Convection has been struggling to initiate along the slowly south/southeastward sagging surface front this afternoon. This is likely due to early morning convection across parts of GA/FL, widespread cloudiness, and poor frontal convergence in the absence of stronger large-scale ascent. The Marginal and Slight risk areas have been trimmed based on latest surface observations, frontal position, and latest model guidance trends. The 5 percent tornado probability has been removed as veered low-level flow has become less favorable for rotation in any more robust cells that may develop. Nevertheless, MLCAPE around 500-1000 J/kg amid effective shear magnitudes of 35+ kt will conditionally support a few strong to severe storms, mainly capable of locally damaging gusts, over the next 2-4 hours. Additional convection is expected to redevelop across parts of the FL Panhandle into southern GA and the Carolinas overnight in a continued warm advection regime. However, this activity is expected to be elevated and pose little severe risk. Some Marginal risk for damaging gusts may persist across parts of north FL overnight into early Thursday morning closer to the effective frontal boundary. ..Leitman.. 03/09/2022 .PREV DISCUSSION... /ISSUED 1011 AM CST Wed Mar 09 2022/ ...FL/GA/SC... Two ongoing clusters of thunderstorms will likely persist through the day, posing a risk of damaging winds or a couple of tornadoes. One cluster is currently over the Big Bend region of FL, and will track across north FL this afternoon. One persistent supercell embedded within this cluster has shown occasional tornado potential. The air mass ahead of the storms is moist and moderately unstable, and convection is likely to continue eastward and offshore through the day. Low level winds will slowly weaken and veer in this area, so the extent of severe risk is uncertain. Nevertheless, given the mesoscale organization of the cluster and sufficient parameter space, will maintain the SLGT risk for this region. The second cluster of storms is over east-central GA along the primary surface boundary. These storms have weakened somewhat during the past couple of hours, but will be moving through a moist and unstable air mass over eastern SC this afternoon. Most model solutions indicate that this activity re-intensifies, with a potential for locally damaging wind gusts and perhaps a tornado or two. Thunderstorms are also expected to re-develop late tonight over parts of southern AL/GA and the FL panhandle. However, these storms should be elevated above a relatively stable surface layer. Therefore it appears the risk of severe storms is quite limited. Read more

No Mesoscale Discussions are in effect as of Wed Mar 9 19:54:01 UTC 2022.

No watches are valid as of Wed Mar 9 19:54:01 UTC 2022.