Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CST Thu Nov 24 2022 Valid 251200Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TEXAS COAST... ...SUMMARY... Isolated strong to severe thunderstorms appear possible mainly Friday night through early Saturday morning along/near parts of the Texas Coast. ...Texas Coast... A large, closed upper low centered over far west TX and adjacent northern Mexico Friday morning should develop slowly eastward across TX through the period. Rich low-level moisture will likely remain confined off the TX Coast during the day, with mainly elevated thunderstorms occurring over much of central/east TX in a low-level warm advection regime. Large-scale ascent preceding the upper low should eventually encourage a weak surface low to develop along the middle TX Coast around Friday evening, and subsequently move northward into parts of east TX Friday night into early Saturday morning. There is still a fair amount of uncertainty regarding the track and strength of this surface low, and the quality of low-level moisture return ahead of it along/near the middle/upper TX Coast. In particular, the latest extended run (15Z) of the RAP seems most aggressive in advancing upper 60s to low 70s surface dewpoints inland across this region, mainly after 03Z Friday evening. If sufficient low-level moisture can advance inland to support surface-based convection, then increasing low-level shear associated with a southerly low-level jet may support a non-zero risk for a tornado or two, along with isolated damaging winds. Strong deep-layer shear also appears more than sufficient for supercells. Have opted to add low severe probabilities for a narrow portion of the TX Coast region in the event adequate low-level moisture does advance slightly inland. ..Gleason.. 11/24/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1041 AM CST Thu Nov 24 2022 Valid 241700Z - 251200Z No Changes, the previous outlook of elevated to locally critical fire weather condition remains valid. See the prior discussion for details. ..Lyons.. 11/24/2022 .PREV DISCUSSION... /ISSUED 1154 PM CST Wed Nov 23 2022/ ...Synopsis... A mid-level trough will continue to move south along the Rockies as surface high pressure and cooler air spreads southward across the CONUS today, limiting wildfire-spread potential across most locales. One exception though would be southern California, where a surface pressure gradient should maximize in intensity as high pressure builds across the Interior West. 20+ mph sustained offshore flow coinciding with 15-20 percent RH necessitates the maintenance of Elevated highlights this outlook. At least locally Critical conditions are also possible, with modest receptiveness of fuels to fire spread the primary mitigating factor for Critical highlights this outlook. ...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 1020 AM CST Thu Nov 24 2022 Valid 241630Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY THROUGH TONIGHT ACROSS THE MID AND UPPER TEXAS INTO SOUTHERN LOUISIANA COASTAL PLAIN...AND PERHAPS PARTS OF CENTRAL TEXAS... ...SUMMARY... Strong thunderstorms may impact parts of central and southeastern Texas into southern Louisiana today into tonight. It is possible that a few of these could pose some risk for severe weather. ...Synopsis... The westerlies appear to be trending more progressive across the northern mid-latitudes of the Pacific through North America, while remaining more amplified in the southern mid- and subtropical latitudes. The latter regime still includes prominent ridging along an axis from the subtropical eastern Pacific into the Pacific Coast states, with a significant downstream low digging along the higher terrain of New Mexico. Models suggest that the mid-level low will continue southward into northern Chihuahua through late tonight, while mid-level ridging develops eastward across and east of the northern Rockies, and downstream short wave troughing digs across the Upper Midwest and Great Lakes region. In lower levels, expansive cold surface ridging is in the process of shifting off the Atlantic Seaboard, but potentially cold air associated with it still lingers across much of the Southeast, and as far southwest as Louisiana/adjacent southeast Texas coastal areas. Only a gradual further modification is forecast, with a reinforcing intrusion of cold air already surging southeast of the Rockies, as far south as the Texas/Oklahoma Panhandle vicinity. As this air spreads across the southern Great Plains toward northwestern Gulf coastal areas, potential for surface cyclogenesis likely will remain suppressed to the lee of the southern Rockies. ...Texas/Louisiana... Sufficient low-level warming and moistening has occurred, in association with southerly return flow around the southwestern periphery of the retreating surface ridge, to contribute to sufficient destabilization for increasing thunderstorm development. Initially, this has been mostly rooted within a lower/mid tropospheric warm advection regime across central through northeastern Texas, above a residual near-surface stable layer. However, this stable layer has become increasingly shallow in a corridor across parts of the Edwards Plateau and Hill Country into the mid/upper Texas coastal plain. In advance of the digging mid-level low, a belt of westerlies emanating from the subtropical eastern Pacific has become increasingly cyclonic across and east of the lower Rio Grande Valley, with some building of downstream ridging across the lower Mississippi Valley into the Southeast. This will generally be maintained through this period, but a smaller-scale short wave perturbation is in the process of progressing through this regime, and may be contributing to recent thunderstorm initiation across parts of Deep South Texas into the upper Texas coastal plain. It appears that this activity will increase in coverage through the day, before spreading into/through the lower Mississippi Valley overnight. This convection will at least inhibit further near-surface destabilization inland of mid/upper Texas coastal areas, if not tend to stabilize the environment, but modest boundary-layer destabilization (CAPE on the order of 500-1000 J/kg) still appears possible near immediate coastal areas. In the presence of strong deep-layer shear (beneath 50+ southwesterly 500 mb flow), any convection supported by inflow of this unstable boundary-layer air may tend to gradually organize. While this could eventually include a couple of supercell structures, the tendency for low-level flow to remain modest or weaken and veer through the day will maintain smallish low-level hodographs and limit the overall severe weather potential. ..Kerr/Thornton.. 11/24/2022 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CST Wed Nov 23 2022 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF SOUTHEAST TEXAS...AND A SMALL PART OF SOUTHWEST LOUISIANA... ...SUMMARY... A few strong to severe storms are possible Thursday from southeast Texas into southwest Louisiana. Locally damaging wind gusts are most likely. ...Discussion... Early day storms are likely to be ongoing over much of northeast TX into AR in a warm advection regime where the 850 mb will be over 30 kt. A few hundred J/kg of elevated CAPE may support a few stronger cores but severe hail is unlikely. Farther south, a quasi-stationary front will extend from southeast TX toward coastal LA, while the cold front remains far to the west. Upper 60s F dewpoints will exist south of the boundary, resulting in favorable SBCAPE over 1000 J/kg. As the upper low drops south across NM and into Far West TX, moderate southwest flow aloft will result in long hodographs across TX and LA. Low-level shear is expected to weaken throughout the day, with 850 winds becoming less than 15-20 kts during the afternoon. However, as early day storms interact along the east-west boundary, localized severe weather may occur as lift and shear will be maximized along it. A weak/brief tornado cannot be ruled out along the boundary. A few showers may occur overnight across southern LA as well, with any surface-based activity likely south of I-10. However, models do not suggest much storm strength at that time with relatively weak warm advection profiles. ..Jewell.. 11/23/2022 Read more

No watches are valid as of Wed Nov 23 17:34:01 UTC 2022.

No Mesoscale Discussions are in effect as of Wed Nov 23 17:34:01 UTC 2022.

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1019 AM CST Wed Nov 23 2022 Valid 231630Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. today through tonight. ...Synopsis... Within a belt of westerlies emanating from the mid-latitude Pacific, models indicate that there will be further amplification within the flow across western North America through this period. This likely will include building mid-level ridging across and inland of the U.S./British Columbia Pacific coast, and digging mid-level troughing within split downstream branches near and east of the Rockies. It still appears that the more amplified of these perturbations will evolve in the southern branch, and include a developing mid-level low near the Colorado into New Mexico Rockies later today through tonight. Farther downstream, as a deep mid-level low continues to form while redeveloping across and southeast of the Canadian Maritimes, it appears that the persistent confluent mid-level regime across the eastern U.S. may become more focused across and just east of the Atlantic Seaboard. Beneath this regime, models indicate that cold surface ridging will be maintained and reinforced across the Atlantic Seaboard. As some erosion of this ridging commences across the northwestern Gulf of Mexico into portions of the southern Great Plains and lower Mississippi Valley, it appears that more prominent surface ridging, developing across the Intermountain West and Rockies, will begin to build into the Great Plains. And, surface cyclogenesis will remain suppressed within weak surface troughing to the lee of the southern Rockies. ...Southern Great Plains vicinity... On the southwestern periphery of the eastern surface ridging, modest low-level moisture return is already underway across and north-northeast of the lower Rio Grande Valley. A gradual moistening likely will continue within a narrow plume on the eastern periphery of a low-level jet (roughly 30+ kt around 850 mb), north-northeastward toward the Ozark Plateau through daybreak Thursday. However, this is occurring above an initially cold/stable surface-based layer. While there probably will be some modification of this air mass today through tonight, low cloud cover and precipitation will contribute to the maintenance of a substantive low-level/near-surface inversion layer across most areas north of the middle Texas coastal plain. Weak boundary-layer destabilization appears possible overnight across the coastal plain, but this seems likely to remain capped beneath warming layers aloft. North of a College Station/Temple line into areas near/northwest of the Ark-La-Tex, strengthening large-scale forcing for ascent is expected to support increasing thunderstorm development late this evening into the overnight hours. Modest to weak elevated instability and shear (within the relevant potential convective layer) likely will minimize the risk for severe weather. ..Kerr/Thornton.. 11/23/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1004 AM CST Wed Nov 23 2022 Valid 231700Z - 241200Z ...NO CRITICAL AREAS... No changes have been made to the current outlook. Brief locally elevated conditions will remain possible today ahead of a surging cold front in eastern CO. However, temporal and spatial coverage should remain below criteria for elevated highlights. Gusty downslope winds and brief elevated fire-weather conditions may develop over portions of the LA basin and southern CA late tonight into early D2/Thur. See the previous discussion. ..Lyons.. 11/23/2022 .PREV DISCUSSION... /ISSUED 0111 AM CST Wed Nov 23 2022/ ...Synopsis... A mid-level trough will deepen across the Rockies, encouraging surface cyclone development across the central/southern High Plains. Dry downslope flow along the lee of the Rockies may encourage brief bouts of Elevated surface conditions across portions of the central High Plains, with the brevity of these conditions precluding fire weather highlights. Elsewhere across the CONUS, relatively quiescent fire weather conditions are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Nov 22 18:18:01 UTC 2022.

No Mesoscale Discussions are in effect as of Tue Nov 22 18:18:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Tue Nov 22 2022 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely on Wednesday. General thunderstorms are likely from northeast Texas into eastern Oklahoma and western Arkansas overnight. ...Discussion... A surface high will remain over the eastern CONUS with winds gradually veering to easterly over the Gulf of Mexico. Modest surface moisture return will occur Wednesday night across southeast TX, as surface pressures lower ahead of an upper low dropping south across CO and NM. Meanwhile, a cold front will surge south across the central and southern High Plains in advance of the upper low, well west of the developing moist plume. Moistening just above the surface will occur from eastern TX into AR as southwesterly 850 mb winds average 30-40 kt. Lift from warm advection will lead to scattered showers, with thunderstorms expected Wednesday night after about 05Z. Forecast soundings show elevated instability up to 500 J/kg developing from central and northern TX into southeast OK, suggesting little if any severe hail threat given only modest effective-layer shear and midlevel lapse rates near 6.5 C/km. ..Jewell.. 11/22/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1032 AM CST Tue Nov 22 2022 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... Brief, locally elevated fire weather conditions are possible today across portions of the High Plains. Dry downslope flow may occasionally gust to near 15 mph with surface humidity below 20%. Freeze cured fuels may support some fire spread, but confidence in higher fire-weather concerns is low. See the previous discussion. ..Lyons.. 11/22/2022 .PREV DISCUSSION... /ISSUED 1246 AM CST Tue Nov 22 2022/ ...Synopsis... A mid-level trough will traverse the Pacific Northwest and amplify over the central Rockies today, with surface high pressure overspreading much of the CONUS, promoting weak surface winds and limiting significant wildfire-growth potential. Dry air will continue to meander across southern California and the central High Plains toward the central Appalachians during the afternoon, supporting brief, localized wildfire-spread potential. ...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 1015 AM CST Tue Nov 22 2022 Valid 221630Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Showers and a couple of thunderstorms with gusty winds are possible late this afternoon across southern Washington and northern Oregon coastal areas. Otherwise, the risk for thunderstorms remains negligible across much of the remainder of the U.S. through tonight. ...Synopsis... Amplification within one belt of westerlies across the mid-latitude Pacific is underway. This is forecast to include large-scale mid-level ridging building across the eastern Pacific, toward the North American coast, later today through tonight. As this occurs, a vigorous downstream short wave trough appears likely to rapidly dig inland of the Pacific Northwest coast by early this evening, and into the Rockies by daybreak Wednesday. Another perturbation is expected to continue digging within a separate branch, across the subtropical eastern Pacific to the west of Baja. Models indicate that flow farther downstream will remain broadly confluent east of the Great Plains through the Atlantic Seaboard. Beneath this regime, although it may continue to slowly weaken, cold surface ridging appears likely to persist across much of the southeastern U.S. into the northwest Gulf coast vicinity. Weak moisture return may commence above this air mass across the lower Rio Grande Valley into parts of the southern Great Plains, and perhaps near southern Atlantic coastal areas. Otherwise, appreciable boundary-layer moistening may remain confined to parts of southeastern Florida, as northeasterly to easterly near surface flow is maintained across the peninsula and northern Gulf of Mexico. ...Pacific Northwest... Low-level moistening maintained in the wake of an inland advancing surface front may be sufficient to contribute to weak boundary-layer destabilization, in the presence of substantive post-frontal mid-level cooling (including 500 mb temps falling to around or below -26C). It appears that this may become supportive of low-topped convection capable of producing at least some lightning across southern Washington/northern Oregon coastal areas by 21-22Z, near or in the wake of a small but rather intense mid-level jet streak (including 70-90+ kt around 500 mb) migrating inland. Given forecast soundings exhibiting 30-40+ kt westerly mean flow in the lowest few kilometers above ground level, locally strong wind gusts aided by downward momentum transfer may be possible in the more vigorous showers/storms. However, activity is still expected to generally remain below severe limits. ..Kerr/Thornton.. 11/22/2022 Read more

No watches are valid as of Mon Nov 21 17:24:02 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Nov 21 17:24:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1103 AM CST Mon Nov 21 2022 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Tuesday. ...Synopsis... Northern stream is expected to remain progressive on Tuesday. A lead shortwave trough will move quickly across the Upper Midwest and Great Lakes while another slightly stronger shortwave moves across the Pacific Northwest/British Columbia and northern Rockies into the northern High Plains. The surface pattern east of the Rockies will be dominated by high pressure, with resulting offshore flow mitigating any potential moisture return. The only exception is across the FL Peninsula, where modest low-level moisture will remain in place. Isolated thunderstorms are possible across the peninsula as easterly low-level flow promotes sea-breeze activity. Modest directional shear is forecast, with low-level easterly flow veering to westerly aloft, but speeds will be low. A strong storm or two is possible, but this shear should limit updraft strength and duration, limiting the overall severe potential. ..Mosier.. 11/21/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Mon Nov 21 2022 Valid 211700Z - 221200Z ...NO CRITICAL AREAS... No changes, fire-weather concerns across the CONUS are low. ..Lyons.. 11/21/2022 .PREV DISCUSSION... /ISSUED 1128 PM CST Sun Nov 20 2022/ ...Synopsis... Surface high pressure and associated cooler air will overspread much of the MS Valley eastward as well as the Interior West while multiple shortwave mid-level troughs traverse the CONUS today. Dry surface air will meander over a long corridor from the central Plains to the OH Valley/central Appalachians this afternoon, perhaps supporting very brief, localized wildfire concerns. Otherwise, widespread, significant wildfire-spread potential appears limited across the CONUS. ...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 1010 AM CST Mon Nov 21 2022 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms remains negligible across much of the U.S. today through tonight. ...Discussion... Mid/upper flow has trended more zonal across North America, with much of the U.S. now most prominently under the influence of westerlies emanating from the mid-latitude Pacific. However, flow remains broadly confluent inland of Pacific coastal areas through the Atlantic Seaboard, with relatively cool and stable conditions only slowly beginning to modify. This includes seasonably cold surface ridging being maintained from the lee of the southern Rockies, as far south as the northwestern Gulf coast vicinity, into the western Atlantic. Although insolation and moistening northeasterly to easterly near-surface flow may begin to modify the boundary layer across the Florida Peninsula (particularly southeastern through east central portions), weak forcing for ascent and mid-level lapse rates may only allow for scattered shower development with some potential to occasionally produce lightning. ..Kerr/Thornton.. 11/21/2022 Read more

No watches are valid as of Sun Nov 20 18:16:02 UTC 2022.

No Mesoscale Discussions are in effect as of Sun Nov 20 18:16:02 UTC 2022.