SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1003 AM CST Sun Dec 22 2024 Valid 221630Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Northern CA/Pacific Northwest coast through tonight... Lightning flashes have been observed this morning within a baroclinic band roughly 150 mi off the northern CA coast, in association with a midlevel shortwave trough that will move inland later today into tonight. The potential for isolated lightning flashes inland will begin this afternoon with elevated convection in the warm conveyor belt across northwest CA/southwest OR. Other isolated lightning flashes may also occur this evening into early tonight along the WA coast as steeper low-midlevel lapse rates and weak buoyancy spread inland. ..Thompson/Moore.. 12/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1003 AM CST Sun Dec 22 2024 Valid 221630Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Northern CA/Pacific Northwest coast through tonight... Lightning flashes have been observed this morning within a baroclinic band roughly 150 mi off the northern CA coast, in association with a midlevel shortwave trough that will move inland later today into tonight. The potential for isolated lightning flashes inland will begin this afternoon with elevated convection in the warm conveyor belt across northwest CA/southwest OR. Other isolated lightning flashes may also occur this evening into early tonight along the WA coast as steeper low-midlevel lapse rates and weak buoyancy spread inland. ..Thompson/Moore.. 12/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 AM CST Sun Dec 22 2024 Valid 221300Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis... Water-vapor imagery this morning shows an upper trough over the eastern Pacific to the west of the Pacific Northwest coast. This upper feature will move east-northeast into British Columbia and WA/OR tonight. Cooling midlevel temperatures will result in weak buoyancy (100-200 J/kg MUCAPE) late today into tonight from portions of northern CA northward along the coastal ranges of OR/WA. Elsewhere, mainly tranquil and stable conditions will prevail across the Lower 48 states. ..Smith/Goss.. 12/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 AM CST Sun Dec 22 2024 Valid 221300Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis... Water-vapor imagery this morning shows an upper trough over the eastern Pacific to the west of the Pacific Northwest coast. This upper feature will move east-northeast into British Columbia and WA/OR tonight. Cooling midlevel temperatures will result in weak buoyancy (100-200 J/kg MUCAPE) late today into tonight from portions of northern CA northward along the coastal ranges of OR/WA. Elsewhere, mainly tranquil and stable conditions will prevail across the Lower 48 states. ..Smith/Goss.. 12/22/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Sun Dec 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... A moderately amplified and more active/progressive southern-stream pattern is still expected later this week, along with a general northward fluctuation of low-level moisture across parts of Texas to the Lower Mississippi Valley and Gulf Coast. After a day of little or no severe-weather potential on Christmas Wednesday/Day 4, severe risks are expected to increase into Days 5-7 Thursday-Saturday. A secondary upper trough is expected to emerge from the Southwest deserts and moves toward the Ozarks/Deep South. This could lead to at least a low-end multi-day severe risk in a corridor from east/southeast Texas and the ArkLaTex to Lower Mississippi Valley. In particular, Thursday/Day 5 could ultimately warrant Slight Risk-caliber severe probabilities across east/southeast Texas, especially if the more southern and more severe-favorable ECMWF model runs become more apparent. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0237 AM CST Sun Dec 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL/SOUTHEAST TEXAS... ...SUMMARY... A few strong storms could occur across parts of south-central and southeast Texas on Tuesday. ...South-central/Southeast Texas... A southern-stream shortwave trough is expected to spread eastward on Tuesday across the south-central Plains toward the Ozarks. Low-level moisture should continue to increase across the Texas coastal plain into south-central Texas during the day. Scattered convection should be ongoing Tuesday morning across north/northeast Texas and the ArkLaTex vicinity, but modest diurnal destabilization should occur ahead of a southeastward-moving effective cold front across south-central to east/southeast Texas. A diurnally related intensification of storms is plausible near the advancing front, and possibly also in the free warm sector during the afternoon. Effective shear will not be overly strong /30-35 kt/, including some flow weakness noted in model soundings around 2-3 km AGL, but nonetheless could be sufficient for some organized storm modes. A few stronger/locally severe storms could occur, including the potential for storm-related wind gusts. ...Northern California/Pacific Northwest... As a prominent upper-level trough moves inland, isolated thunderstorms will be possible across northern California coastal areas and interior valley mainly through the morning and early afternoon, and possibly on a more isolated basis across other parts of the coastal Pacific Northwest. ..Guyer.. 12/22/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0237 AM CST Sun Dec 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL/SOUTHEAST TEXAS... ...SUMMARY... A few strong storms could occur across parts of south-central and southeast Texas on Tuesday. ...South-central/Southeast Texas... A southern-stream shortwave trough is expected to spread eastward on Tuesday across the south-central Plains toward the Ozarks. Low-level moisture should continue to increase across the Texas coastal plain into south-central Texas during the day. Scattered convection should be ongoing Tuesday morning across north/northeast Texas and the ArkLaTex vicinity, but modest diurnal destabilization should occur ahead of a southeastward-moving effective cold front across south-central to east/southeast Texas. A diurnally related intensification of storms is plausible near the advancing front, and possibly also in the free warm sector during the afternoon. Effective shear will not be overly strong /30-35 kt/, including some flow weakness noted in model soundings around 2-3 km AGL, but nonetheless could be sufficient for some organized storm modes. A few stronger/locally severe storms could occur, including the potential for storm-related wind gusts. ...Northern California/Pacific Northwest... As a prominent upper-level trough moves inland, isolated thunderstorms will be possible across northern California coastal areas and interior valley mainly through the morning and early afternoon, and possibly on a more isolated basis across other parts of the coastal Pacific Northwest. ..Guyer.. 12/22/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 AM CST Sun Dec 22 2024 Valid 231200Z - 241200Z ...NO CRITICAL AREAS... ...Synopsis... A weak shortwave trough will overspread the southern Rockies, promoting weak lee cyclogenesis and locally dry/breezy conditions over the TX Trans-Pecos region. However, these conditions will be too marginal for any fire-weather concerns. ..Weinman.. 12/22/2024 ...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 0141 AM CST Sun Dec 22 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A shortwave trough and accompanying jet streak will cross the northern Rockies, while a related lee cyclone/trough briefly deepens over the central and southern Plains. As a result, locally dry/breezy conditions are possible over portions of the southern High Plains, though fire-weather concerns will be low. ..Weinman.. 12/22/2024 ...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 1259 AM CST Sun Dec 22 2024 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Discussion... A shortwave trough is expected to amplify from the central Rockies to the south-central High Plains on Monday. Weak surface wave development is expected across Texas into southern Oklahoma, with a modest increase in low-level moisture across central/east Texas into southern Oklahoma in advance of a cold front moving southeastward across the southern High Plains. Increasing forcing for ascent and elevated moisture transport should lead to increasing elevated convection Monday night across north/northeast Texas into southeast Oklahoma and the ArkLaTex. While a mid-level capping inversion may tend to persist, updrafts should increasingly reach a sufficient depth/temperature late Monday night into early Tuesday for at least isolated thunderstorms. Severe thunderstorms are not currently expected given access to only weak elevated buoyancy. Isolated thunderstorms will also be possible late Monday night across the coastal Pacific Northwest and northern California as weak buoyancy develops with an upper trough approaching the coast and an inland-moving frontal band. ..Guyer.. 12/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1142 PM CST Sat Dec 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A low chance of general thunderstorms is forecast across parts of the Pacific Northwest. Severe storms are unlikely. ...Synopsis... An upper trough will lift out of the eastern states, with a surface high from New England to the northern Gulf Coast. High pressure will also exist over much of the Intermountain West, but lower pressure will affect parts of the West Coast as an upper trough nears. Cooling aloft will occur through this evening across much of WA, OR, and northern CA. As midlevel moisture increases, weak elevated instability may support isolated thunderstorms, primarily after 21Z. Despite strong shear profiles, such minimal elevated instability is unlikely to support a severe hail risk. ..Jewell/Weinman.. 12/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1142 PM CST Sat Dec 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A low chance of general thunderstorms is forecast across parts of the Pacific Northwest. Severe storms are unlikely. ...Synopsis... An upper trough will lift out of the eastern states, with a surface high from New England to the northern Gulf Coast. High pressure will also exist over much of the Intermountain West, but lower pressure will affect parts of the West Coast as an upper trough nears. Cooling aloft will occur through this evening across much of WA, OR, and northern CA. As midlevel moisture increases, weak elevated instability may support isolated thunderstorms, primarily after 21Z. Despite strong shear profiles, such minimal elevated instability is unlikely to support a severe hail risk. ..Jewell/Weinman.. 12/22/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 PM CST Sat Dec 21 2024 Valid 220100Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected across the USA through tomorrow morning. The minimal thunderstorm threat has ended over parts of the Pacific Northwest as rapid warming aloft is underway behind a compact shortwave trough. Instability is not expected to materialize downstream into ID and MT, and as such all thunderstorm probabilities have been removed. Elsewhere, high pressure over the East and a dry air mass over land will maintain stable conditions. ..Jewell.. 12/22/2024 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0319 PM CST Sat Dec 21 2024 Valid 231200Z - 291200Z A series of mid-level troughs will encourage multiple rounds of surface cyclone development across the central CONUS, reinforcing surface high pressure west of the Rockies and along/east of the Appalachians through next week. Low-level moisture, and meaningful precipitation accumulations across the Intermountain West toward the southern and eastern U.S., as well as cooler surface conditions over the northern CONUS, should hold wildfire-spread conditions at bay. Occasionally dry and breezy conditions may develop by afternoon peak heating most days over the southern High Plains, driven by downslope flow west of the aforementioned surface cyclones. However, modest fuel receptiveness, and the brevity/localized nature of any dry or windy conditions, should generally limit significant wildfire-spread potential. ..Squitieri.. 12/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more