Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1026 AM CST Thu Dec 08 2022 Valid 081630Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm threat appears negligible through early Friday. ...TX to TN... Morning surface analysis shows a quasi-stationary boundary extending from central TX northeastward into the TN Valley. Rich low-level moisture is present to the south of the boundary, with dewpoints in the mid-upper 60s noted. However, poor mid-level lapse rates and relatively warm temperatures aloft will limit CAPE values and the overall threat of deep convection. This corridor also lies beneath general large-scale ridging, suggesting little organized lift will occur. Therefore, scattered showers but only isolated thunderstorms are expected in vicinity of the front this forecast period. ..Hart/Squitieri.. 12/08/2022 Read more

No watches are valid as of Wed Dec 7 17:45:01 UTC 2022.

No Mesoscale Discussions are in effect as of Wed Dec 7 17:45:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CST Wed Dec 07 2022 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States on Thursday. ...Synopsis... A mid-level disturbance, embedded within strong high-level flow from the Desert Southwest through the Mid-Atlantic states, will move from the central Rockies to the middle MS Valley during the period. Only weak surface reflection is expected over the central U.S. with much of the stronger large-scale forcing for ascent displaced north of a front draped from OK eastward across the Mid South. Showers and a few elevated thunderstorms will likely be ongoing Thursday morning from OK and the Ozarks, with this activity moving east across KY/TN during the day. Additional isolated storms are possible later in the day from parts of north TX to the AR/TN/MS vicinity. However, weak lapse rates and associated buoyancy will limit storm intensity. Elsewhere, showers and couple of thunderstorms are possible along the Pacific Northwest coast as an upstream mid-level trough moves ashore. ..Smith.. 12/07/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1038 AM CST Wed Dec 07 2022 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below. ..Thornton.. 12/07/2022 .PREV DISCUSSION... /ISSUED 0103 AM CST Wed Dec 07 2022/ ...Synopsis... Fire weather concerns will be limited for today across the country. Dry conditions are expected to persist across the central High Plains where a dry air mass remains in place (dewpoints in the low to mid teens). Afternoon RH values in the 25-35% range over a region with modestly dry fuel introduces the potential for low-end fire weather concerns. However, wind speeds are expected to largely be limited given weak cyclogenesis across the southern High Plains and a building surface high over the northern Plains/upper MS River Valley. Latest ensemble guidance supports this idea with low probability for widespread winds above 15 mph. Localized elevated conditions are possible across eastern CO, southeast WY and adjacent areas of NE/KS, but the potential appears too limited for highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1022 AM CST Wed Dec 07 2022 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... Around the northwest periphery of the persistent mid-upper ridge over the Gulf of Mexico, a shortwave trough over the Great Basin will eject eastward to the southern Rockies. A cool air mass entrenched from much of OK and northwest TX northward will yield muted lee cyclogenesis downstream of the ejecting trough, such that the surface baroclinic zone will move little from north TX to the TN Valley through tonight. Isolated thunderstorms will be possible, mainly through this afternoon, along the front from the Mid-South into the TN Valley, and over the Four Corners vicinity in association with the Great Basin trough. Scattered thunderstorms are most likely this evening into tonight as low-level warm theta-e advection strengthens from west TX towards the Ozarks. Much of this activity should remain on the cool side of the baroclinic zone. Marginal mid-level lapse rates resulting in weak elevated buoyancy should preclude appreciable severe potential. ..Grams/Squitieri.. 12/07/2022 Read more

No watches are valid as of Tue Dec 6 17:46:02 UTC 2022.

No Mesoscale Discussions are in effect as of Tue Dec 6 17:46:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1105 AM CST Tue Dec 06 2022 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather is not forecast across the U.S. on Wednesday. ...Synopsis... A mid-level trough initially over the Mojave Desert will move east through the Great Basin and to the central Rockies by early Thursday morning. A larger-scale mid-level trough will pivot east from the Upper Midwest to the Northeast while weak mid-level ridging occurs over the middle MS Valley in its wake. In the low levels, a cold front will slide southeast across KY/TN and the Mid-Atlantic states and Northeast during the period. The stalled western portion of the boundary will advance northward as a warm front from the OK-TX Red River into central OK by late Wednesday night. Scattered showers and isolated thunderstorms are likely during the morning from the MS-AR Delta region east-northeastward into WV/western VA with lower coverage farther west in north TX. Sporadic shower/thunderstorm activity will probably linger from MS westward into north TX during the afternoon. As low-level warm-air advection intensifies during the evening into the overnight across the southern Great Plains, scattered thunderstorms will likely develop near the front. Moist profiles yielding modest lapse rates will limit storm intensity and severe weather is not expected. ..Smith.. 12/06/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1037 AM CST Tue Dec 06 2022 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 12/06/2022 .PREV DISCUSSION... /ISSUED 1225 AM CST Tue Dec 06 2022/ ...Synopsis... Fire weather concerns remain limited for today across the CONUS. Recent low-level water vapor imagery continues to show modest subsidence/drying in the lee of the southern Rockies amid a persistent west/southwest flow regime aloft. This pattern will be maintained over the next 24 hours as the upper low over CA gradually translates east. Consequently, another day of dry, breezy conditions is expected across eastern NM in the lee of terrain features. Localized elevated conditions may materialize as far east as the western TX Panhandle, but the combination of low probability for sub-20% RH away from terrain features, weakening boundary-layer winds, and unreceptive fuels (ERCs near or below seasonal average) will limit the overall fire weather threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Tue Dec 06 2022 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WESTERN PORTIONS OF KY/TN... ...SUMMARY... A severe thunderstorm or two is possible this evening across western portions of Kentucky and Tennessee. ...Western KY/TN vicinity... Boundary-layer dewpoints into the mid 60s are present south of a warm front that extends from central AR to southern TN. The warm front should make some northward progress into western KY by this evening ahead of a weak wave over the Ozarks. Clouds will remain pervasive, but occasional breaks should help boost MLCAPE to between 500-750 J/kg. The bulk of convective development this evening should be focused within the warm conveyor regime ahead of the frontal wave and north of the surface warm front. Still, there are some indications for convection to backbuild southwestward into the warm sector over a portion of western KY/TN. Moderate low-level hodograph curvature in conjunction with a relatively elongated/straight-line mid to upper-level hodograph would be conditionally supportive of low-end supercell development. While it is plausible that severe storms may ultimately fail to materialize, there appears to be enough signal to warrant a low probability for a brief tornado and locally damaging winds. ..Grams/Squitieri.. 12/06/2022 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0111 PM CST Mon Dec 05 2022 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... No updates are needed to for the D2 Fire Weather Outlook. See previous discussion below for more details. ..Thornton.. 12/05/2022 .PREV DISCUSSION... /ISSUED 0138 AM CST Mon Dec 05 2022/ ...Synopsis... Fire weather concerns are expected to remain minimal for Tuesday across the country. A dry air mass is expected to linger across portions of the southern and central High Plains. Modest downslope flow will foster another day of 25-35% RH by late afternoon with west winds near 15 mph. Localized elevated conditions are possible from eastern NM and southern CO in the lee of terrain features into portions of the TX Panhandle. However, ERCs across this region are expected to remain near to below seasonal average and will limit the overall fire weather potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Mon Dec 5 19:14:02 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Dec 5 19:14:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CST Mon Dec 05 2022 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast over the contiguous United States on Tuesday. ...Synopsis... A large mid- to upper-level trough will remain over central Canada with cyclonic flow moving through its base over the north-central states and Upper Great Lakes. Located to the south over the Midwest, strong west-southwesterly mid-level flow will extend from the Great Lakes southwestward through the central Great Plains and into the Desert Southwest, ahead of a eastward-migrating mid-level low over CA. A gradual modification/moistening of a continental-polar airmass will occur over the Arklatex through the Mid South and into the southern part of the OH Valley during the period. Weak warm-air advection near and south of a front will aid in episodic shower/thunderstorm development from the Mid South into parts of the OH Valley. Weak buoyancy will lead to elevated thunderstorms, but storm intensity will likely remain limited. ..Smith.. 12/05/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1026 AM CST Mon Dec 05 2022 Valid 051700Z - 061200Z ...NO CRITICAL AREAS... No updates are needed to the current D1 Fire Weather Outlook. See previous discussion below for more details. ..Thornton.. 12/05/2022 .PREV DISCUSSION... /ISSUED 1246 AM CST Mon Dec 05 2022/ ...Synopsis... Fire weather concerns will remain limited for today across the CONUS. Early-morning surface observations show a cold front surging southward across the northern/central Plains, but is expected to stall across parts of southern KS/northern OK by the afternoon hours. Strengthening westerly gradient winds ahead of the front are expected across eastern NM into west TX and the TX Panhandle. Downslope warming/drying will boost temperatures above seasonal normal and foster RH reductions into the 25-35% range. Pockets of elevated conditions are possible, but will most likely occur over areas that received some wetting rainfall over the past 72 hours and/or have ERC values below seasonal average. The combination of unreceptive fuels and low confidence in the spatial/temporal coverage of elevated conditions precludes highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1006 AM CST Mon Dec 05 2022 Valid 051630Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... West-southwesterly lower-level flow will persist through tonight across a large swath of the southern states, between a deep low over western Hudson Bay and a subtropical ridge over the western Gulf of Mexico. Despite modest mid-level lapse rates, a gradual increase in low-level warm/moist advection will support an expanding plume of meager elevated buoyancy from the Lower MS Valley across the TN Valley and eventually the southern Appalachians. This should support isolated thunderstorms beginning this evening and persisting overnight. Farther west, a couple thunderstorms are possible in the El Paso, TX vicinity during the late afternoon to early evening where scant but uncapped surface-based buoyancy is anticipated on the west edge of the southern-stream moisture plume. A few thunderstorms will also be possible across the Sacramento Valley and northern CA coast in association with cool mid-level temperatures/steep lapse rates as a mid-level low near the CA/OR coastal border drifts south through early Tuesday. ..Grams/Squitieri.. 12/05/2022 Read more

No watches are valid as of Sun Dec 4 17:43:02 UTC 2022.

No Mesoscale Discussions are in effect as of Sun Dec 4 17:43:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CST Sun Dec 04 2022 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S., Monday through Monday night. ...Synopsis... Higher latitude blocking, including one prominent mid-level ridge across the Greenland vicinity, likely will be maintained through this period and beyond. To the southwest of this ridge, a broad mid-level low continues to evolve across much of Canada and the northern tier of the U.S. (to the east of the Rockies), with some retrogression of its deep center to the west-northwest of Hudson Bay forecast through Monday/Monday night. As this occurs, models indicate that cold surface ridging will build and begin to nose southward to the lee of the Canadian Rockies, preceded by a more modest cold intrusion across much of the Upper Midwest, upper Mississippi Valley and northern into central Great Plains by 12Z Tuesday. A prior cold front is now in the process of stalling across the south Atlantic and Gulf Coast vicinity, and is forecast to weaken/ retreat northward beneath a modestly amplified belt of westerlies emanating from the mid-latitude eastern Pacific. By late Monday into Monday night, it appears that this will include building mid-level ridging across the Southeast (to the north of a prominent subtropical high centered near the Yucatan Peninsula) and digging, positively tilted large-scale troughing near and to the west of California and Baja California. Downstream of this troughing, a plume of lower/mid-tropospheric moist return flow, which has developed off the lower latitude eastern Pacific, may become suppressed south of the Southwestern international border vicinity by 12Z Monday. But mid-level moisture return will continue around the western/northwestern periphery of the downstream ridging, across Texas and the lower Mississippi Valley into the western slopes of the southern Appalachians and surrounding Southeast. At the same time, it appears that modest ongoing low-level moisture return, emanating from the western Gulf of Mexico, will gradually spread from southern/eastern Texas through much of the Mid South and Tennessee Valley vicinity, while also increasing off the northwestern Gulf into the central Gulf Coast states. ...Gulf Coast/Southeast... Warming mid-level temperatures probably will cap weak surface-based (or near surface-based) destabilization across much of the Gulf coastal plain Monday through Monday night. However, despite generally weak mid-level lapse rates, elevated moisture return farther north may contribute to weak destabilization and convection rooted within a developing persistent lower/mid tropospheric warm advection regime, across the Mid South into southern Appalachians vicinity. This may include occasional embedded thunderstorm development, aided by mid/upper provided by weak perturbations migrating around the periphery of the subtropical ridge. ...Northern California vicinity... Weak instability beneath the mid-level cold core of a remnant digging cyclonic circulation will contribute to the risk for convection occasionally capable of producing lightning, from near coastal areas into the Sierra Nevada. ..Kerr.. 12/04/2022 Read more