SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Wed Nov 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND COASTAL PACIFIC NORTHWEST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts and perhaps a tornado or two. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Rich low-level moisture will continue to stream northward today across parts of the lower MS Valley into the Mid-South as an upper trough over the Plains continues eastward towards the OH Valley. Primary surface low and better forcing associated with this upper trough are forecast to remain well north of the inland-advancing warm sector. Even so, scattered surface-based thunderstorms should develop by this afternoon as a remnant/weak surface low off the LA Coast moves slowly inland. Filtered daytime heating of the moist low-level airmass should result in modest instability developing by this afternoon, even though mid-level lapse rates will remain poor (see 12Z JAN/LIX soundings). Low-level southerly flow will not be overly strong across the lower MS Valley, but gradual veering and strengthening of winds with height through mid levels should support sufficient deep-layer shear for modest updraft organization. A few marginal supercells/clusters may pose an isolated threat for strong to damaging winds as they spread eastward across LA/MS this afternoon and evening. Enough low-level shear should also be present to foster some updraft rotation and the threat for a tornado or two, with an isolated severe threat potentially continuing into tonight across parts of southwest AL and vicinity. The warm sector will become increasingly pinched off with northward extent in MS and western TN, with convection generally expected to outpace the low-level moisture return. Given the expected mismatch of stronger forcing/shear farther north and better instability to the south, have opted to maintain the Marginal Risk this update, with some expansion based on latest guidance trends. ...Coastal Pacific Northwest... Cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates associated with an eastward-moving upper trough will help support weak instability today across parts of the coastal Pacific Northwest (reference 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Gleason/Bentley.. 11/13/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ...D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ...D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CST Wed Nov 13 2024 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Friday. ...Synopsis... An intensifying deep-layer low is forecast to be near the NC coast at the start of the period Friday morning. This low will move east-southeastward away from the coast through the day, as a trailing cold front moves through the FL Peninsula and Gulf of Mexico. Elsewhere, a deep mid/upper-level trough will move slowly eastward across the western CONUS. Generally limited moisture/instability will result in low thunderstorm potential across most of the CONUS. Some deeper convection may persist near the NC coast early in the period in association with the departing low. Otherwise, weak convection with isolated lightning flashes cannot be ruled out across parts of CA/NV into the Great Basin/northern Rockies, though confidence in sufficient instability and lightning coverage is too low to add any general thunderstorm areas across the West at this time. ..Dean.. 11/13/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CST Wed Nov 13 2024 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Friday. ...Synopsis... An intensifying deep-layer low is forecast to be near the NC coast at the start of the period Friday morning. This low will move east-southeastward away from the coast through the day, as a trailing cold front moves through the FL Peninsula and Gulf of Mexico. Elsewhere, a deep mid/upper-level trough will move slowly eastward across the western CONUS. Generally limited moisture/instability will result in low thunderstorm potential across most of the CONUS. Some deeper convection may persist near the NC coast early in the period in association with the departing low. Otherwise, weak convection with isolated lightning flashes cannot be ruled out across parts of CA/NV into the Great Basin/northern Rockies, though confidence in sufficient instability and lightning coverage is too low to add any general thunderstorm areas across the West at this time. ..Dean.. 11/13/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CST Wed Nov 13 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong storms will be possible near the central and northeast Gulf Coasts early on Thursday, and later across coastal parts of the Carolinas Thursday evening and night. Organized severe potential appears relatively low at this time. ...Synopsis... A negatively tilted mid/upper-level trough initially over the Midwest/Ohio Valley is forecast to dig southeastward on Thursday and evolve into a closed mid/upper-level low as it approaches the Mid Atlantic. As this occurs, a surface low is forecast to deepen Thursday night along a frontal boundary near the Coastal Carolinas. Farther west, a mid/upper-level shortwave trough is forecast to move eastward and amplify as it approaches the Pacific Coast and eventually moves inland. ...Central/northeast Gulf Coast vicinity... Thunderstorms will likely be ongoing Thursday morning across parts of AL/GA and the FL Panhandle, aided by the mid/upper-level shortwave trough moving across the Ohio Valley and attendant low-level jet. Low-level flow will tend to veer and weaken through the day, which will tend to result in less convective organization with time. However, if organized convection from late on D1/Wednesday can persist into Thursday morning, then rich low-level moisture and sufficient low-level and deep-layer shear could support a threat of isolated damaging winds and possibly a tornado. Probabilities may eventually be needed if it appears that some severe threat may continue from overnight Wednesday into the first part of Thursday. ...Coastal Carolinas... Uncertainty remains regarding the northward extent of appreciable surface moistening/destabilization near the Coastal Carolinas, as the surface low deepens and tracks east-northeastward into Friday morning. However, there appears to be some potential for the effective warm front to overlap parts of coastal NC and the Outer Banks during the evening, as stronger deep-layer flow and ascent overspread the region. Increasingly widespread precipitation will tend to limit destabilization, but favorable wind profiles will support organized convective potential where modest buoyancy can develop. Probabilities may eventually be needed near the coast and Outer Banks, if confidence increases regarding the potential for isolated damaging winds and/or a tornado later in the forecast period. ..Dean.. 11/13/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1247 AM CST Wed Nov 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Thursday. Areas across the Northeast will see an increase in cloud cover and moisture as a warm front lifts northward and showery activity brings periods of precipitation. Across the Plains and northern Rockies, enhanced westerly flow aloft will overspread the Rockies with potential for an increase in surface winds and a few regions where relative humidity reductions to around 20 percent will be possible. Overall, the overlap of strongest winds and lowest relative humidity where fuels are receptive appears low. ..Thornton.. 11/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1246 AM CST Wed Nov 13 2024 Valid 131200Z - 141200Z ...Synopsis... ...Northeast/New England... Gusty post-frontal offshore flow will continue across the northeastern US today, with potential for relative humidity reductions to around 30-40 percent and northwesterly winds around 10 mph gusting 20-25 mph. An Elevated delineation was maintained with this outlook to cover this threat. Winds should gradually weaken through the afternoon as high pressure builds in across the region. ...Appalachians Tennessee/North Carolina border through the West Virginia-Virginia Border... Strong southeast winds further enhanced by downslope flow will bring areas of locally Elevated fire weather concerns to portions of the Appalachians near the TN/NC border through the WV/VA border. Relative humidity reductions to around 20-25 percent may overlap with enhanced flow in favored north facing slopes. Wetting rainfall will overspread this region Wednesday night into Thursday. ..Thornton.. 11/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 PM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY...AND ALONG THE WEST COAST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts. A potential for severe gusts could also develop along parts of the West Coast. ...Lower Mississippi Valley... An upper-level trough will move eastward across the southern Plains today, as a low-level jet strengthens ahead of the system, over the lower to mid Mississippi Valley. At the surface, a moist airmass will be in place over the lower Mississippi Valley where surface dewpoints will be from the mid 60s to lower 70s F. As moisture advection continues this morning into afternoon, a pocket of instability is forecast to develop over parts of eastern Louisiana and western Mississippi. Thunderstorms appear likely to develop within this pocket of instability around midday, with additional storms developing further to the east in the vicinity of the central Gulf Coast. RAP and NAM forecast soundings in the lower Mississippi Valley suggest that MLCAPE could peak across southeast Louisiana in the 1500 to 2000 J/kg range around 21Z. At that time near the instability max, 0-6 km shear is forecast to be near 30 knots. Some directional is evident below 850 mb but lapse rates at low and mid-levels are forecast to be poor. This environment could support a marginal wind-damage threat associated with rotating storms or semi-organized line segments. A marginal tornado threat could also develop if any rotating storms can move through the stronger instability while remaining discrete. The marginal severe threat may continue into early evening as a line segment moves into the central Gulf Coast. ...West Coast... A shortwave trough is forecast to approach the West Coast today and move inland late this afternoon into this evening. Ahead of the trough, strong large-scale ascent will support isolated thunderstorm development along the coasts of northern California, Oregon and Washington. Model forecasts suggest that flow at 850 mb will be around 30 knots, with 700-500 mb lapse rates peaking near 7 C/km. This environment could be favorable for marginally severe gusts mainly after 21Z as the trough approaches the coast. The potential for isolated severe gusts may continue into the evening, as the trough moves inland. ..Broyles/Thornton.. 11/13/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 PM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY...AND ALONG THE WEST COAST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts. A potential for severe gusts could also develop along parts of the West Coast. ...Lower Mississippi Valley... An upper-level trough will move eastward across the southern Plains today, as a low-level jet strengthens ahead of the system, over the lower to mid Mississippi Valley. At the surface, a moist airmass will be in place over the lower Mississippi Valley where surface dewpoints will be from the mid 60s to lower 70s F. As moisture advection continues this morning into afternoon, a pocket of instability is forecast to develop over parts of eastern Louisiana and western Mississippi. Thunderstorms appear likely to develop within this pocket of instability around midday, with additional storms developing further to the east in the vicinity of the central Gulf Coast. RAP and NAM forecast soundings in the lower Mississippi Valley suggest that MLCAPE could peak across southeast Louisiana in the 1500 to 2000 J/kg range around 21Z. At that time near the instability max, 0-6 km shear is forecast to be near 30 knots. Some directional is evident below 850 mb but lapse rates at low and mid-levels are forecast to be poor. This environment could support a marginal wind-damage threat associated with rotating storms or semi-organized line segments. A marginal tornado threat could also develop if any rotating storms can move through the stronger instability while remaining discrete. The marginal severe threat may continue into early evening as a line segment moves into the central Gulf Coast. ...West Coast... A shortwave trough is forecast to approach the West Coast today and move inland late this afternoon into this evening. Ahead of the trough, strong large-scale ascent will support isolated thunderstorm development along the coasts of northern California, Oregon and Washington. Model forecasts suggest that flow at 850 mb will be around 30 knots, with 700-500 mb lapse rates peaking near 7 C/km. This environment could be favorable for marginally severe gusts mainly after 21Z as the trough approaches the coast. The potential for isolated severe gusts may continue into the evening, as the trough moves inland. ..Broyles/Thornton.. 11/13/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Tue Nov 12 2024 Valid 130100Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN HIGH PLAINS INTO FAR SOUTHWEST KANSAS... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Texas South Plains and Oklahoma/Texas Panhandle vicinity into far southwestern Kansas this evening, possibly accompanied by some risk for hail and isolated severe gusts. ...Southern High Plains Into Far Southwest Kansas... A mid-level trough is evident on water vapor imagery over the southern Rockies, with a plume of mid-level moisture extending from northern Mexico northeastward across the southern Plains into the mid Mississippi Valley. At the surface, an axis of maximized low-level moisture is located across west Texas, where surface dewpoints are in the 55 to 60 F range. As low-level moisture advection continues across the southern High Plains this evening, a pocket of instability is expected to develop over the eastern Texas Panhandle, where the RAP is forecasting MUCAPE to approach 1500 J/kg by midnight. The instability, along with increasing large-scale ascent, associated with the approaching mid-level trough, will likely support isolated thunderstorm development near the instability axis late this evening. Convective coverage is expected to expand as cells move eastward across southern Kansas and western Oklahoma during the early overnight period. Forecast soundings near the instability axis at 06Z have an inversion from the surface to 850 mb suggesting that the storms will be elevated. Above the inversion, 700-500 mb lapse rates are forecast to be near 7 C/km, with effective shear near 40 knots. This may be enough for rotating cells capable of producing isolated large hail. A chance for isolated severe gusts will also exist, but this will be a lesser threat. ..Broyles.. 11/13/2024 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0335 PM CST Tue Nov 12 2024 Valid 141200Z - 201200Z Upper-level troughing is expected over both the East and West Coasts Day 3/Thursday - Day 5/Saturday, with upper-level ridging slowly shifting from over the central US to over portions of the eastern US. There is forecast uncertainty regarding how this amplified upper-level pattern progresses early next week, which will have ramifications for potential fire weather concerns in southern/central California and the Northeast. ...Northeast and Mid-Atlantic... An approaching warm front with associated cloud cover and possible shower activity will limit fire weather concerns across the Mid-Atlantic and into portions of the Northeast on Day 3/Thursday. However, dry/breezy conditions are likely to develop across portions of the Mid-Atlantic and Northeast Day 4/Friday - Day 6/Saturday. Given the recent drought, lack of forecast rain, and near to record high fire danger, 40% probabilities were expanded and introduced during what appears to be a multi-day fire weather episode. Some forecast uncertainty remains regarding forecast precipitation and where the greatest overlap of elevated/critical winds/RH will be, but confidence is increasing in at least elevated fire weather conditions for portions of New Jersey, eastern Pennsylvania, the Hudson Valley/vicinity, and southern New England late this week through the weekend. ...Southern/central California... Breezy/gusty north-northwest winds are possible in portions of central/southern California Day 5/Saturday into Day 7/Monday as multiple cold fronts sweep south and east over the region. The southern extent of forecast precipitation and the magnitude of these winds remain uncertain precluding 40% areas at this time. Confidence is increasing in an offshore/Santa Ana wind event mid-next week, which is on the edge of the outlook period. This event may start on Day 8/Tuesday and last multiple days. This will be monitored and if trends hold, probabilities will likely be added in subsequent extended outlooks. ..Nauslar.. 11/12/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Nov 12 20:12:02 UTC 2024.

No Mesoscale Discussions are in effect as of Tue Nov 12 20:12:02 UTC 2024.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0158 PM CST Tue Nov 12 2024 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Texas South Plains and Oklahoma/Texas Panhandle vicinity into far southwestern Kansas this evening, possibly accompanied by some risk for hail and gusty winds. ...20Z Update... The primary change to this outlook was to expand Marginal Risk probabilities northward into portions of far southwestern KS. Here, guidance consensus depicts 700-1000 J/kg MUCAPE amid elongated hodographs, which may support an instance or two of marginally severe hail with the more persistent, discrete updrafts that can form. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 11/12/2024 .PREV DISCUSSION... /ISSUED 1024 AM CST Tue Nov 12 2024/ ...Southern High Plains... An upper-level trough over the eastern Great Basin/Four Corners at midday will continue eastward toward the south-central High Plains tonight. Gradual lee-side cyclogenesis will occur particularly late today into tonight, with a sharpening southern High Plains dryline/lee trough, with an eastward-moving Pacific cold front that will overtake the dryline/lee trough from west-to-east tonight. Modest-caliber low-level moisture return will occur north-northwestward across the southern High Plains, with surface dewpoints tending to remain limited to the upper 40s/lower 50s F into this evening. It still appears likely that deep convective potential across northwest Texas and the Oklahoma/Texas Panhandles will remain limited through peak heating, owing to the moisture limitations and a persistent capping inversion. Isolated thunderstorm development will become more probable after sunset as lift associated with a strengthening low-level jet increases, and as the surface cold front overtakes the lee trough. While MUCAPE is expected to remain rather weak (generally 500-1000 J/kg or less), strong deep-layer shear will support organized updrafts with any sustained convection. Isolated hail appears to be the main threat, as thunderstorms should have a tendency to remain slightly elevated. But, some chance for strong/gusty winds may also exist. The window for severe hail should remain small in space and time this evening, as convection will likely grow upscale fairly quickly. Even so, small hail may occur farther north/east into parts of Kansas and Oklahoma overnight into early Wednesday morning. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0158 PM CST Tue Nov 12 2024 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Texas South Plains and Oklahoma/Texas Panhandle vicinity into far southwestern Kansas this evening, possibly accompanied by some risk for hail and gusty winds. ...20Z Update... The primary change to this outlook was to expand Marginal Risk probabilities northward into portions of far southwestern KS. Here, guidance consensus depicts 700-1000 J/kg MUCAPE amid elongated hodographs, which may support an instance or two of marginally severe hail with the more persistent, discrete updrafts that can form. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 11/12/2024 .PREV DISCUSSION... /ISSUED 1024 AM CST Tue Nov 12 2024/ ...Southern High Plains... An upper-level trough over the eastern Great Basin/Four Corners at midday will continue eastward toward the south-central High Plains tonight. Gradual lee-side cyclogenesis will occur particularly late today into tonight, with a sharpening southern High Plains dryline/lee trough, with an eastward-moving Pacific cold front that will overtake the dryline/lee trough from west-to-east tonight. Modest-caliber low-level moisture return will occur north-northwestward across the southern High Plains, with surface dewpoints tending to remain limited to the upper 40s/lower 50s F into this evening. It still appears likely that deep convective potential across northwest Texas and the Oklahoma/Texas Panhandles will remain limited through peak heating, owing to the moisture limitations and a persistent capping inversion. Isolated thunderstorm development will become more probable after sunset as lift associated with a strengthening low-level jet increases, and as the surface cold front overtakes the lee trough. While MUCAPE is expected to remain rather weak (generally 500-1000 J/kg or less), strong deep-layer shear will support organized updrafts with any sustained convection. Isolated hail appears to be the main threat, as thunderstorms should have a tendency to remain slightly elevated. But, some chance for strong/gusty winds may also exist. The window for severe hail should remain small in space and time this evening, as convection will likely grow upscale fairly quickly. Even so, small hail may occur farther north/east into parts of Kansas and Oklahoma overnight into early Wednesday morning. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0113 PM CST Tue Nov 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not currently expected on Thursday. ...Synopsis... A negatively titled shortwave trough is forecast to extend from the Upper Midwest into the southern Appalachians early Thursday morning. This trough is expected to lose amplitude as it continues eastward while also developing a closed mid-level circulation. This resulting cyclone will then likely progress across the Upper OH Valley and into the Mid-Atlantic by early Friday. In response to this evolution, surface cyclogenesis is anticipated off the Carolina coast, or perhaps just inland over the coastal Carolinas. Farther west, the overall upper pattern will amplify as ridging builds across the Plains and troughing deepens along the West Coast. ...Central/Northeast Gulf Coast vicinity... Showers and thunderstorms will likely be ongoing over the central Gulf Coast early Thursday morning, as a cold front pushes eastward through moist and modestly buoyant warm sector in place across the region. Northern extent of this warm sector is expected to become increasingly confined throughout the day with the cooler, more continental airmass over the Carolinas and Mid-Atlantic remaining place. A strong storm or two is possible within this warm sector, particularly Thursday morning from southwest/southern AL into the western FL Panhandle, but limited buoyancy and weakening shear should keep any severe threat isolated, precluding the need for any severe probabilities with this outlook. ...Coastal Carolinas... Uncertainty regarding the strength and location of the surface low expected to deepen over the region late Thursday night/early Friday morning limits the confidence on how far inland any favorable low-level moisture/buoyancy would penetrate. Current guidance suggests there could be a confined area along the warm front near the northern NC Coast where there is enough overlap between modest buoyancy and strong shear to support some severe potential. Given the limited spatial extent of this region and the general uncertainty regarding the overall pattern, no severe probabilities were introduced with this outlook. However, a small area maybe needed in future outlooks if forecast confidence increases. ..Mosier.. 11/12/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0113 PM CST Tue Nov 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not currently expected on Thursday. ...Synopsis... A negatively titled shortwave trough is forecast to extend from the Upper Midwest into the southern Appalachians early Thursday morning. This trough is expected to lose amplitude as it continues eastward while also developing a closed mid-level circulation. This resulting cyclone will then likely progress across the Upper OH Valley and into the Mid-Atlantic by early Friday. In response to this evolution, surface cyclogenesis is anticipated off the Carolina coast, or perhaps just inland over the coastal Carolinas. Farther west, the overall upper pattern will amplify as ridging builds across the Plains and troughing deepens along the West Coast. ...Central/Northeast Gulf Coast vicinity... Showers and thunderstorms will likely be ongoing over the central Gulf Coast early Thursday morning, as a cold front pushes eastward through moist and modestly buoyant warm sector in place across the region. Northern extent of this warm sector is expected to become increasingly confined throughout the day with the cooler, more continental airmass over the Carolinas and Mid-Atlantic remaining place. A strong storm or two is possible within this warm sector, particularly Thursday morning from southwest/southern AL into the western FL Panhandle, but limited buoyancy and weakening shear should keep any severe threat isolated, precluding the need for any severe probabilities with this outlook. ...Coastal Carolinas... Uncertainty regarding the strength and location of the surface low expected to deepen over the region late Thursday night/early Friday morning limits the confidence on how far inland any favorable low-level moisture/buoyancy would penetrate. Current guidance suggests there could be a confined area along the warm front near the northern NC Coast where there is enough overlap between modest buoyancy and strong shear to support some severe potential. Given the limited spatial extent of this region and the general uncertainty regarding the overall pattern, no severe probabilities were introduced with this outlook. However, a small area maybe needed in future outlooks if forecast confidence increases. ..Mosier.. 11/12/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CST Tue Nov 12 2024 Valid 131200Z - 141200Z The Elevated area was expanded slightly based on the latest high-resolution forecast guidance and current dry/windy conditions. Elsewhere, locally elevated conditions are possible in portions in southwest Texas and along the Sierra Front. Locally elevated conditions are also possible in the Appalachians from Tennessee-North Carolina border through the West Virginia-Virginia border as southeast winds strengthen with some downslope enhancement ahead of precipitation Wednesday night. ..Nauslar.. 11/12/2024 .PREV DISCUSSION... /ISSUED 0200 AM CST Tue Nov 12 2024/ ...Synopsis... Gusty post-frontal off-shore flow will continue across portions of the Northeast from far eastern PA and southern NJ extending northeast through southern New England. A very dry air mass will remain in place with relative humidity reductions to around 30-35 percent likely. Given the drought conditions and receptive fuels in this region, an Elevated delineation was maintained with this outlook. Locally Critical conditions may be possible, though the limited spatial extent of this threat precludes the need to include a Critical area at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MISSISSIPPI VALLEY/CENTRAL GULF COAST REGION...AND COASTAL PORTIONS OF PACIFIC NORTHWEST... ...SUMMARY... A marginal tornado/wind threat is apparent on Wednesday afternoon into Wednesday night across a part of the central Gulf Coast States. Thunderstorms with strong to locally severe gusts are also possible near the immediate coasts of Washington, Oregon, and northern California. ...Synopsis... A shortwave trough is forecast to move from the Plains through the MS Valley on Wednesday, becoming more negatively tilted as it does. An occluded surface low associated with this system will begin the period over the mid MO Valley before moving eastward across IA and reaching the northern IL early Thursday morning. More consequently for the severe-weather potential, a secondary triple-point low is expected to progress eastward across the northern portion of the Southeast states, along the northern edge of an eastward-evolving warm sector. Cold front associated with this low will gradually move eastward across the Southeast states during the day. Farther west, an upper-level trough is forecast to progress farther inland across the western CONUS, as an embedded shortwave trough moves across northern CA into the interior Northwest/northern Great Basin. ...Lower Mississippi Valley/Central Gulf Coast... General expectation is for a triple-point surface low to evolve over the Mid-South vicinity through the early afternoon as low-level moisture continues to advect northward across the central Gulf Coast region. Dewpoints in the upper 60s/low 70s are anticipated ahead of this low and associated cold front. The airmass is expected to destabilize amid this low-level moisture, but overall buoyancy will still be modest given the lack of steep lapse rates. The combination of destabilization and increasing ascent is forecast to result in thunderstorm development across the warm sector, but along and ahead of the eastward-progressing cold front. The stronger shear will likely be displaced north of the stronger buoyancy, but enough shear is expected across the warm sector to support organized storms if updrafts can persist and deepen. This evolution could support a few marginal supercells and/or stronger clusters during the afternoon and evening, with a threat of locally damaging winds and possibly a tornado or two. Elevated storms will also be possible through the day/evening to the north of the richer surface moisture. While effective shear will be sufficient for a few strong elevated storms, the severe potential with northward extent will tend to be limited by weak midlevel lapse rates and generally marginal buoyancy. ...WA/OR/Northern CA coasts... Cold mid-level temperatures (i.e. -24 to -28 deg C at 500 mb) associated with the upper trough are expected to spread eastward throughout the day. These cold mid-level temperatures and associated steep mid-level lapse rates will contribute to modest buoyancy along the coastal portions of the Pacific Northwest. Highest storm coverage is anticipated over the northern CA coast vicinity from the late morning into the early afternoon along as the frontal band moves through, but persistent forcing for ascent within this modestly buoyant airmass is expected to result in more cellular storms throughout the remainder of the afternoon and evening. A more linear mode is anticipated within the frontal band, with a few convectively enhanced gusts possible. Low-topped cellular activity is anticipated in the wake of the frontal band, with a few instances of small hail, and potentially even a brief tornado, possible. ..Mosier.. 11/12/2024 Read more