SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1030 AM CST Sun Dec 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTH TEXAS TO THE OZARKS... ...SUMMARY... Isolated severe hail, strong/gusty winds, and perhaps a tornado may occur tonight through early Monday morning from parts of north Texas to the Ozarks. ...Synopsis... Gradual amplification and consolidation of upper troughing will occur through the period across parts of the northern Plains and Upper Midwest. The southern fringe of this upper trough will begin to influence and overspread portions of the central/southern Plains late this evening and overnight. The primary surface low will develop towards the international border region of northern MN/southern Canada, while partially modified Gulf moisture continues to gradually stream northward over portions of the southern Plains into the Ozarks ahead of a cold front. ...Eastern Oklahoma into Western Arkansas and Southwest Missouri... Convective initiation will likely be delayed until 03Z or later this evening across eastern OK/western AR vicinity, as low-level warm/moist advection aids in the northward transport of a moist low-level airmass. Once convection develops as glancing ascent from the approaching upper trough overspreads the warm sector, convective mode may quickly become messy, as generally southwesterly low/mid-level flow encourages updraft interactions and mergers. Even so, around 1000-2000 J/kg of MUCAPE, aided by modestly steepened mid-level lapse rates, should support robust updrafts. Coupled with sufficient (around 30-40 kt) deep-layer shear, some of this initial development could produce marginally severe hail on an isolated basis. Based on latest guidance trends showing convective initiation farther north across parts of northern OK into southwest MO, the Marginal Risk has been expanded northward to account for this initial hail threat. Poor/neutral low-level lapse rates and a generally saturated boundary-layer shown in various NAM/RAP forecast soundings limit confidence to some extent in the potential for truly surface-based thunderstorms tonight across the warm sector. Still, the presence of a 35-45 kt southwesterly low-level jet, with associated 0-1 km SRH sufficient for low-level updraft rotation, suggests a non-zero threat for a tornado along with some potential for occasional strong/gusty winds as convection spreads eastward across eastern OK into western AR and the Ozarks through early Monday morning. The potential for sustained supercells appears limited by a weakness in the flow/hodograph forecast around 700 mb, with the southward-moving cold front also encouraging a more linear/cluster mode with time. Overall, the severe threat with any convection that develops should remain rather isolated, but within a conditionally somewhat favorable environment. ..Gleason/Squitieri.. 12/15/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1032 AM CST Sun Dec 15 2024 Valid 151700Z - 161200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 12/15/2024 .PREV DISCUSSION... /ISSUED 0155 AM CST Sun Dec 15 2024/ ...Synopsis... Embedded within stronger quasi-zonal flow aloft, a shortwave trough is forecast to rapidly eject eastward from the Intermoutnain West across the central and northern Rockies early this morning. As lift from the trough shifts east, a lee low and trailing surface trough will quickly deepen across parts of the High Plains, while a cold front will approach from the interior West. The strong mid-level flow and lee low will support downslope winds across portions of the central High Plains, and to a lesser degree across eastern NM and far West TX. These strong winds of 20-30 mph may briefly overlap with areas of moderately low RH this afternoon. While there is some risk, fire-weather concerns are not expected to be widespread, given the brief nature of the strong winds and lower RH, as well as the passage of the cold front later this afternoon and into the evening. ...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 0624 AM CST Sun Dec 15 2024 Valid 151300Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF NORTH TEXAS TO THE OZARKS... ...SUMMARY... Isolated hail near severe limits is possible tonight from portions of north Texas to the Ozarks. ...Synopsis... In mid/upper levels, a low-amplitude longwave pattern will remain in place over the CONUS, with progressive shortwave to synoptic troughs traversing the prevailing westerlies. The leading trough -- currently anchored by a closed low near the northern IL/IN border -- should devolve to an open wave and move to the northern Mid-Atlantic region by 12Z tomorrow. Meanwhile, a series of shortwaves and vorticity lobes -- occupying broadly cyclonic flow over much of the western CONUS -- will consolidate/phase somewhat through the period while shifting eastward. By 00Z, a loosely organized synoptic trough will extend from the Dakotas across the central High Plains to AZ. Overnight, a closed 500-mb low should develop over southern MB, with the trough extending across central NE/KS to southern NM and northwestern MX by 12Z. At the surface, 11Z analysis showed a decaying cold to stationary front from eastern IL across southern AR, north-central and west- central TX. This boundary will move slowly northward through the day and continue to weaken. Meanwhile, cold frontogenesis is forecast today ahead of the mid/upper trough, and over parts of the central/northern Plains. This Plains front should reach western parts of MN/IA, northeastern to south-central KS, and the TX Panhandle by 00Z. By 12Z, the cold front should reach central/ southern IL, the Ozarks, eastern/southern OK, and the TX South Plains region. ...North TX to the Lower OH Valley... Episodic, isolated to scattered thunderstorms are expected throughout the period, embedded in a plume of low-level warm/moist advection and moisture transport extending from central/east TX to the lower Ohio Valley. Through the day, this activity will occur in weak midlevel lapse rates and modest deep shear, with most or all of it elevated over a relatively stable, near-surface layer, and accordingly minimal severe potential. Meanwhile, surface dewpoints in the 60s F will spread northward into and across much of the outlook area, as the older boundary becomes diffuse ahead of the Plains cold front. Concurrent with height falls aloft and increasing deep shear, the warm conveyor and accompanying isentropic ascent to LFC should intensify this evening amid mass response to the consolidation/ approach of the mid/upper trough, and related 45-55-kt LLJ. Greatest thunderstorm coverage in the plume is expected after about 03Z from near the Red River Valley to the Ozarks, spreading into the lower Ohio Valley from around 09Z onward. During phases when convection is still relatively discrete, and around the southern part of denser/later convective coverage, the most vigorous cells may produce severe hail. Forecast soundings show a nearly saturated, near-neutral stability profile in the boundary layer over north TX to eastern OK, and perhaps into some of northwestern AR, depending on outflow timing/intensity. This renders profiles that may be effectively surface-based, with MLCAPE in the 1000-1500 J/kg rage and slightly greater MUCAPE, but still often containing weak, near-surface static stability. At this time, severe-gust/tornado potential appears too conditional and low to draw even marginal categorical probabilities for those hazards, and the previous outlook area still appears to capture the consensus of most probable, favorably positioned convection in the plume as well. ..Edwards/Goss.. 12/15/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0624 AM CST Sun Dec 15 2024 Valid 151300Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF NORTH TEXAS TO THE OZARKS... ...SUMMARY... Isolated hail near severe limits is possible tonight from portions of north Texas to the Ozarks. ...Synopsis... In mid/upper levels, a low-amplitude longwave pattern will remain in place over the CONUS, with progressive shortwave to synoptic troughs traversing the prevailing westerlies. The leading trough -- currently anchored by a closed low near the northern IL/IN border -- should devolve to an open wave and move to the northern Mid-Atlantic region by 12Z tomorrow. Meanwhile, a series of shortwaves and vorticity lobes -- occupying broadly cyclonic flow over much of the western CONUS -- will consolidate/phase somewhat through the period while shifting eastward. By 00Z, a loosely organized synoptic trough will extend from the Dakotas across the central High Plains to AZ. Overnight, a closed 500-mb low should develop over southern MB, with the trough extending across central NE/KS to southern NM and northwestern MX by 12Z. At the surface, 11Z analysis showed a decaying cold to stationary front from eastern IL across southern AR, north-central and west- central TX. This boundary will move slowly northward through the day and continue to weaken. Meanwhile, cold frontogenesis is forecast today ahead of the mid/upper trough, and over parts of the central/northern Plains. This Plains front should reach western parts of MN/IA, northeastern to south-central KS, and the TX Panhandle by 00Z. By 12Z, the cold front should reach central/ southern IL, the Ozarks, eastern/southern OK, and the TX South Plains region. ...North TX to the Lower OH Valley... Episodic, isolated to scattered thunderstorms are expected throughout the period, embedded in a plume of low-level warm/moist advection and moisture transport extending from central/east TX to the lower Ohio Valley. Through the day, this activity will occur in weak midlevel lapse rates and modest deep shear, with most or all of it elevated over a relatively stable, near-surface layer, and accordingly minimal severe potential. Meanwhile, surface dewpoints in the 60s F will spread northward into and across much of the outlook area, as the older boundary becomes diffuse ahead of the Plains cold front. Concurrent with height falls aloft and increasing deep shear, the warm conveyor and accompanying isentropic ascent to LFC should intensify this evening amid mass response to the consolidation/ approach of the mid/upper trough, and related 45-55-kt LLJ. Greatest thunderstorm coverage in the plume is expected after about 03Z from near the Red River Valley to the Ozarks, spreading into the lower Ohio Valley from around 09Z onward. During phases when convection is still relatively discrete, and around the southern part of denser/later convective coverage, the most vigorous cells may produce severe hail. Forecast soundings show a nearly saturated, near-neutral stability profile in the boundary layer over north TX to eastern OK, and perhaps into some of northwestern AR, depending on outflow timing/intensity. This renders profiles that may be effectively surface-based, with MLCAPE in the 1000-1500 J/kg rage and slightly greater MUCAPE, but still often containing weak, near-surface static stability. At this time, severe-gust/tornado potential appears too conditional and low to draw even marginal categorical probabilities for those hazards, and the previous outlook area still appears to capture the consensus of most probable, favorably positioned convection in the plume as well. ..Edwards/Goss.. 12/15/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0312 AM CST Sun Dec 15 2024 Valid 181200Z - 231200Z ...DISCUSSION... A surface cold front will move south and east across the eastern and southeastern U.S. on Day 4/Wed, moving offshore the Gulf and Atlantic coasts by early Day 5/Thu. Showers and thunderstorms are possible near the cold front across parts of the Southeast and Mid-Atlantic vicinity on Day 4/Wed. However, weak instability and only modest vertical shear is expected to limit severe thunderstorm potential. After Day 4/Wed, a mean upper level trough will persist over the eastern half of the CONUS, while an amplified upper ridge develops over the West. As the early period cold front continues to intrude southward across the Gulf of Mexico, boundary-layer moisture will become scant across the CONUS, and offshore trajectories will persist through the period. This overall pattern will result in limited thunderstorm potential beyond Day 4/Wed, and severe storms are not expected. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0159 AM CST Sun Dec 15 2024 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Tuesday. ...Synopsis... Westerly flow across much of the CONUS will become more amplified as a shortwave trough deepens and develops east from the northern/central Rockies to the Upper Midwest vicinity on Tuesday. The southwest extent of the upper trough will lag, remaining over the Southern Rockies/Four Corners vicinity. Stronger mid/upper level southwesterly flow associated with the deepening trough will extend from OK/KS to the Great Lakes. At the surface, a cold front from the Mid-South vicinity into central TX will stall or even retreat northward. Southerly low-level flow will maintain 50s and 60s dewpoints ahead of the front across southern TX toward the ArkLaTex. Isolated to scattered thunderstorm are possible in this warm-advection regime amid modest elevated instability. However, stronger height falls will remain displaced to the north, and large-scale ascent will be nebulous across the warm sector. Additionally, forecast soundings indicate weak vertical shear and poor low-level lapse rates. As such, severe thunderstorm potential is expected to be low. ..Leitman.. 12/15/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0159 AM CST Sun Dec 15 2024 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Tuesday. ...Synopsis... Westerly flow across much of the CONUS will become more amplified as a shortwave trough deepens and develops east from the northern/central Rockies to the Upper Midwest vicinity on Tuesday. The southwest extent of the upper trough will lag, remaining over the Southern Rockies/Four Corners vicinity. Stronger mid/upper level southwesterly flow associated with the deepening trough will extend from OK/KS to the Great Lakes. At the surface, a cold front from the Mid-South vicinity into central TX will stall or even retreat northward. Southerly low-level flow will maintain 50s and 60s dewpoints ahead of the front across southern TX toward the ArkLaTex. Isolated to scattered thunderstorm are possible in this warm-advection regime amid modest elevated instability. However, stronger height falls will remain displaced to the north, and large-scale ascent will be nebulous across the warm sector. Additionally, forecast soundings indicate weak vertical shear and poor low-level lapse rates. As such, severe thunderstorm potential is expected to be low. ..Leitman.. 12/15/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 AM CST Sun Dec 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive and mostly zonal mid-level flow pattern is expected over the CONUS D2/Mon. A pronounced shortwave trough within the stronger westerly flow will move quickly eastward over the northern third of the CONUS. At the surface, cyclone associated with the mid-level trough will move along the US/Canadian border, trailing a cold front over the central US. In the wake of the front, a much colder air mass and modest high pressure are likely over the western 2/3rds of the US. This should keep winds relatively light and RH values elevated. Additionally precipitation ahead of the front and from the prior day will augment fuels, such that little or no fire-weather risk is expected. ..Lyons.. 12/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 AM CST Sun Dec 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive and mostly zonal mid-level flow pattern is expected over the CONUS D2/Mon. A pronounced shortwave trough within the stronger westerly flow will move quickly eastward over the northern third of the CONUS. At the surface, cyclone associated with the mid-level trough will move along the US/Canadian border, trailing a cold front over the central US. In the wake of the front, a much colder air mass and modest high pressure are likely over the western 2/3rds of the US. This should keep winds relatively light and RH values elevated. Additionally precipitation ahead of the front and from the prior day will augment fuels, such that little or no fire-weather risk is expected. ..Lyons.. 12/15/2024 ...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 0155 AM CST Sun Dec 15 2024 Valid 151200Z - 161200Z ...NO CRITICAL AREAS... ...Synopsis... Embedded within stronger quasi-zonal flow aloft, a shortwave trough is forecast to rapidly eject eastward from the Intermoutnain West across the central and northern Rockies early this morning. As lift from the trough shifts east, a lee low and trailing surface trough will quickly deepen across parts of the High Plains, while a cold front will approach from the interior West. The strong mid-level flow and lee low will support downslope winds across portions of the central High Plains, and to a lesser degree across eastern NM and far West TX. These strong winds of 20-30 mph may briefly overlap with areas of moderately low RH this afternoon. While there is some risk, fire-weather concerns are not expected to be widespread, given the brief nature of the strong winds and lower RH, as well as the passage of the cold front later this afternoon and into the evening. ..Lyons.. 12/15/2024 ...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 0155 AM CST Sun Dec 15 2024 Valid 151200Z - 161200Z ...NO CRITICAL AREAS... ...Synopsis... Embedded within stronger quasi-zonal flow aloft, a shortwave trough is forecast to rapidly eject eastward from the Intermoutnain West across the central and northern Rockies early this morning. As lift from the trough shifts east, a lee low and trailing surface trough will quickly deepen across parts of the High Plains, while a cold front will approach from the interior West. The strong mid-level flow and lee low will support downslope winds across portions of the central High Plains, and to a lesser degree across eastern NM and far West TX. These strong winds of 20-30 mph may briefly overlap with areas of moderately low RH this afternoon. While there is some risk, fire-weather concerns are not expected to be widespread, given the brief nature of the strong winds and lower RH, as well as the passage of the cold front later this afternoon and into the evening. ..Lyons.. 12/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 AM CST Sun Dec 15 2024 Valid 161200Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is expected to be low on Monday. ...TX/OK/MO to the Lower MS Valley... An upper trough over the northern/central Plains and Upper Midwest Monday morning will weaken as it shifts east/northeast across the Great Lakes. The strongest deep-layer southwesterly flow associated with this system will mainly be focused over the Mid/Lower MO and Mid-MS Valleys into the Great Lakes. Though, modest vertical shear will extend as far south as eastern OK and the Ozarks into the ArkLaTex vicinity. At the surface, a cold front is forecast to extend from southeast MO into southeast OK and northwest Texas Monday morning. This front will track east/southeast through the period, becoming positioned from the TN Valley toward the ArkLaTex and central TX by Tuesday morning. Ahead of the front, upper 50s to mid 60s dewpoints will be maintained by south/southwesterly low-level flow from central TX toward the MO Bootheel and the Lower MS Valley. Scattered elevated thunderstorms are likely to be ongoing from eastern OK into southern MO and parts of AR. Additional convection will develop near the southeast-advancing cold front as far northeast as the Lower OH Valley and southeast into central TX and the ArkLaTex/Lower MS Valley through the period. Stronger large-scale ascent and vertical shear will remain focused north, and out of phase with, the area of better low-level moisture across the south-central states. A couple of stronger storms may produce small hail early in the period from eastern OK toward the MO Bootheel. However, low-level inhibition and poor low-level lapse rates are expected to limit surface-based instability. Deep-layer flow parallel to the surface boundary, limited surface-based instability, and weakening shear/ascent with southward extent, should limit overall severe potential on Monday. ..Leitman.. 12/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0636 PM CST Sat Dec 14 2024 Valid 150100Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... Overall thunderstorm coverage will remain very isolated tonight. Convection near the cold core of a shortwave trough over central MO has nocturnally weakened. Still, scant elevated buoyancy might yield sporadic flashes as the trough continues east towards southern IN, and within the broad but modest low-level warm conveyor arcing back into the Ark-La-Miss. Greater buoyancy will remain confined to east TX but weak large-scale ascent suggests thunderstorm probabilities will be low. Sporadic thunderstorms may linger longest across parts of the Pacific Northwest coast. Here, steep mid-level lapse rates around 8 C/km per 00Z UIL/SLE soundings will eventually weaken as mid-level temperatures warm from south to north in the early morning. ..Grams.. 12/15/2024 Read more

No Mesoscale Discussions are in effect as of Sat Dec 14 22:22:02 UTC 2024.

No watches are valid as of Sat Dec 14 22:22:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0320 PM CST Sat Dec 14 2024 Valid 161200Z - 221200Z A quasi-zonal, progressive upper-level pattern will be present this weekend into the middle of next week. Thereafter, some flow amplification is forecast to occur. Upper-level troughing will be the general pattern in the East with ridging over portions of the West. This pattern will favor cold air east of the Divide with seasonably warm temperatures farther west. Some colder air/high pressure will filter into the Great Basin and drive offshore winds in parts of southern California. With the passage of successive upper-level shortwave troughs, some dry and breezy conditions are possible in parts of the High Plains. Where precipitation remains minimal, locally heightened fire concerns could develop next week. Given the cooler temperatures expected, critical fire weather probability will remain low. Offshore flow in southern California will likely be the main area of concern for fire weather. The offshore pressure gradient still appears it will be maximized Tuesday night into Wednesday morning. Deterministic and ensemble guidance has not changed significantly in terms of the upper-level and surface pattern over the past several model cycles. Upper-level wind support should be minimal. The main variation in guidance is with the magnitude of the offshore pressure gradient. 40% critical probabilities will remain for Tuesday/Wednesday and trends in the offshore gradient will continue to be monitored. ..Wendt.. 12/14/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Sat Dec 14 2024 Valid 142000Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not expected through tonight. ...20Z Update... The western edge of thunderstorm probabilities have been trimmed in the middle MS Valley vicinity, where additional thunderstorm development appears unlikely behind the strongly forced band of convection shifting eastward -- in tandem with the midlevel shortwave trough. Farther west, thunderstorm probabilities were also removed over portions of the Coastal Range in northern CA. Forecast soundings suggest EL temperatures/instability are no longer supportive of lightning here. For additional details, see the previous discussion below. ..Weinman.. 12/14/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Sat Dec 14 2024/ ...Coastal California... The Marginal Risk across parts of coastal CA has been removed with this update. The 12Z OAK sounding showed a dearth of boundary-layer instability, and a line of low-topped convection has weakened as it moves inland in tandem with a shortwave trough also tracking quickly eastward. While strong winds will remain possible in the short term given the enhanced low/mid-level flow noted on recent VWPs from KMUX, the lack of appreciable surface-based instability is expected to limit the overall severe threat for the rest of the period. ...East/Southeast Texas... A shortwave trough over the southern/central Plains this morning will continue to eject eastward across the mid MS Valley through tonight. Related surface low over eastern KS is forecast to weaken in this time frame, as high pressure will remain entrenched over the East Coast. A cold front is expected to stall over parts of east to central TX later today. While a favorably moist low-level airmass will be in place ahead of this front, limited large-scale ascent and poor lapse rates aloft should hinder robust updrafts and organized severe potential across east/southeast TX. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Sat Dec 14 2024 Valid 142000Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not expected through tonight. ...20Z Update... The western edge of thunderstorm probabilities have been trimmed in the middle MS Valley vicinity, where additional thunderstorm development appears unlikely behind the strongly forced band of convection shifting eastward -- in tandem with the midlevel shortwave trough. Farther west, thunderstorm probabilities were also removed over portions of the Coastal Range in northern CA. Forecast soundings suggest EL temperatures/instability are no longer supportive of lightning here. For additional details, see the previous discussion below. ..Weinman.. 12/14/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Sat Dec 14 2024/ ...Coastal California... The Marginal Risk across parts of coastal CA has been removed with this update. The 12Z OAK sounding showed a dearth of boundary-layer instability, and a line of low-topped convection has weakened as it moves inland in tandem with a shortwave trough also tracking quickly eastward. While strong winds will remain possible in the short term given the enhanced low/mid-level flow noted on recent VWPs from KMUX, the lack of appreciable surface-based instability is expected to limit the overall severe threat for the rest of the period. ...East/Southeast Texas... A shortwave trough over the southern/central Plains this morning will continue to eject eastward across the mid MS Valley through tonight. Related surface low over eastern KS is forecast to weaken in this time frame, as high pressure will remain entrenched over the East Coast. A cold front is expected to stall over parts of east to central TX later today. While a favorably moist low-level airmass will be in place ahead of this front, limited large-scale ascent and poor lapse rates aloft should hinder robust updrafts and organized severe potential across east/southeast TX. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 12/14/2024 .PREV DISCUSSION... /ISSUED 0202 AM CST Sat Dec 14 2024/ ...Synopsis... As the mid-level trough ejects over the central Rockies and into the Plains early D2/Sunday, a lee low and trailing surface trough will quickly deepen across parts of the High Plains. At the same time, a cold front will approach from the interior West. Aided by strong mid-level westerlies at the base of the trough and downslope pressure gradients, several hours of strong surface winds (20-30 mph) are likely across parts of the central High Plains. These strong winds may briefly overlap with areas of moderately low RH (~30%) across western NE and eastern WY. Farther south into eastern NM and far West TX, lower RH will remain possible with more mild temperatures and diurnal minimums of 20-25%. However, winds here are expected to be slower and more transient, owing to the weaker surface pressure falls and flow aloft. The net result will be a few hours of locally dry and breezy conditions in the lee of the Rockies where fuels are somewhat dry. While there is some risk, fire-weather concerns are not expected to be widespread, given the brief nature of the strong winds and lower RH, as well as the passage of the cold front Sunday evening. ...Please see www.spc.noaa.gov/fire for graphic product... Read more