Severe Storms

No Mesoscale Discussions are in effect as of Mon Aug 28 21:42:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CDT Mon Aug 28 2023 Valid 301200Z - 051200Z Tropical storm (soon to be hurricane) Idalia will move into the Southeast on Wednesday bringing strong winds and heavy rain to much of Georgia and Florida, into the Carolinas. On the western periphery of this tropical system, dry northerly winds may result in some elevated to critical fire conditions in drought stricken regions from central Texas to western Mississippi. An amplifying mid-level trough will cross Montana on Wednesday with a surface low and cold front also traversing the state. In the wake of this cold front, dry and breezy westerly flow is expected across northern and eastern Montana. Some dry and breezy conditions are expected in a similar region on Thursday, but rainfall Wednesday night and Thursday may result in some wetting rain and limit fire weather concerns, at least for some portions of north-central and eastern Montana. Several days of dry and breezy conditions are expected from Nevada to Wyoming beneath moderate mid-level flow and a deeply mixed airmass. However, fuels across this region do not support significant fire spread due to recent precipitation. ..Bentley.. 08/28/2023 ...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 0245 PM CDT Mon Aug 28 2023 Valid 282000Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON ACROSS PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated storms capable of strong and gusty winds are possible across the Southeast this afternoon. ...20Z Update... ...Southeast... 18Z soundings sampled a moist, moderately buoyant, and weakly sheared environment across the region. This matches the overall expectation outlined in the previous outlook (appended below), with a predominantly disorganized multicellular storm mode anticipated. Isolated water-loaded downbursts remain possible, particularly from southern MS and across much of AL where the highest storm coverage is anticipated. ...Central/Southern High Plains... Convective initiation has already occurred across the high terrain, with southeastward motion still expected to take these storms into the High Plains. Mesoanalysis estimated effective bulk shear is already 20 to 25 kt across the region, with some additional increase anticipated throughout the afternoon. As such, some organization is possible, with an attendant threat for a strong gust or two. Overall coverage is still expected to remain too low for an outlook area. ..Mosier.. 08/28/2023 .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Aug 28 2023/ ...Southeast this afternoon... A weak midlevel trough persists from the northern Gulf of Mexico to the southern Appalachians with multiple embedded vorticity maxima. Vertical shear is very weak across the Southeast, and thermodynamic profiles are less favorable for strong downdrafts compared to previous days. Thus, scattered pulse-type storms are expected this afternoon along a combination of a stalled synoptic front, weak differential heating zones and local sea breeze circulations. The wind-damage threat appears to be on the lower margins for an outlook area, but will maintain the 5% area for the possibility of isolated downbursts. ...Central/southern High Plains this afternoon/evening... Similar to yesterday, a few storm clusters will form this afternoon and move south-southeastward from southeast WY across eastern CO into eastern NM through this evening. Effective bulk shear of 25-30 kt will support semi-organized storms, a few of which could produce gusty outflow winds and small hail. However, the storms will be relatively low topped for late summer and the severe threat appears too marginal to add an outlook area. ...Tropical cyclone Idalia and FL... Tropical storm Idalia is expected to become a hurricane later today into tonight while moving northward toward the southeast Gulf of Mexico (please refer to latest NHC advisories for additional information). The stronger wind profiles and associated supercell threat will likely be delayed in FL until Tuesday during the day, so will not add any tornado probabilities in this update. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0245 PM CDT Mon Aug 28 2023 Valid 291200Z - 301200Z CORRECTED FOR INCORRECT GRAPHIC An Elevated fire-weather area has been added for southwest Idaho and vicinity where winds of 25 to 30 mph and single digit relative humidity are expected. Much of the Great Basin fuels are too moist to support fire spread. However, across southwest Idaho, there was less recent rainfall and therefore, fuels may be at least somewhat susceptible to large fire, especially given the very windy and dry conditions anticipated. No changes were made elsewhere. See previous discussion below. ..Bentley.. 08/28/2023 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon Aug 28 2023/ ...Synopsis... On Tuesday, a trough will bring an increase in shower and thunderstorm activity across the Pacific Northwest, along with pre-frontal breezy conditions across portions Montana. Across the Southern Plains pressure gradients will increase between the Southwest high and a tropical system impacting the Gulf of Mexico, leading to an increase in surface winds. ...North-Central Texas and Southern Oklahoma... Winds speeds will increase to around 10-15 mph Tuesday afternoon across portions of north-central Texas and southern Oklahoma amid afternoon relative humidity reductions to around 20-30 percent. Fuels within this region remain critically dry, as very little rain has fallen across this region in the last 7 days and prolonged drought has led to drought stress. Given that relative humidity looks to largely stay above Critical thresholds, an Elevated delineation should cover the larger threat well. ...North-Central Montana... Pre-frontal winds will increase to around 15-20 mph amid relative humidity reductions to around 20-25 percent across north-central Montana Tuesday afternoon. Fuels within this region have experienced some drying due to lack of recent rainfall. However, fuels largely remain at or below average precluding the need for Critical highlights and as such an Elevated delineation was most appropriate. ...Dry Thunderstorms... An increase in shower and thunderstorm chances is possible across the Pacific Northwest on Tuesday. Precipitable water values across eastern Washington, northern Idaho, and western Montana will range around 0.50-1.00" with potential for fast storm motions. This will likely result in a mix of wet and dry thunderstorm activity. Ensemble data from the HREF indicates the more appreciable rainfall may be more likely across northern Idaho/western Montana with amounts generally up to and less than 0.10" across eastern Washington across the Cascades and central Columbia Basin. This will need to be monitored for inclusion of isolated dry thunderstorms. For now, confidence remains low in exactly which areas will remain mostly dry. ...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 1227 PM CDT Mon Aug 28 2023 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHWEST/WEST-CENTRAL FLORIDA PENINSULA... ...SUMMARY... The potential for a few tornadoes should gradually increase along/near parts of the Florida Gulf Coast and into north Florida through Tuesday night as Tropical Cyclone Idalia approaches. ...Florida into Southeast Georgia... Latest forecast for TC Idalia centers the system northwest of western Cuba early Tuesday morning, with northeastward/north-northeastward motion taking the storm to just off northwestern FL Peninsula by 12Z Wednesday morning. Strong low/mid-level flow associated with this system will gradually spread northward across the FL Peninsula throughout the day, with the strongest winds expected along the western coast after 00Z. Rain bands will likely begin moving across the peninsula during the early afternoon, with a generally northeastward storm motion anticipated. Lapse rates will be poor, but the moist airmass across the region will still support moderate buoyancy and the potential for a few strong updrafts. The most significant increases in low-level shear are not expected under after 00Z, so the severe-gust and tornado potential with these multicellular bands will be low, but not zero. After 00Z through the remainder of the period, strengthening low to mid-level flow will result in a gradually increasing tornado potential, particular along the west-central and northwest portions of the FL Peninsula. TC tornado climatology shows a notable preference for tornadoes between 200-300 km northeast of the center for northeastward progressing major hurricanes. This matches well with the most favorable environmental conditions for tornadogenesis in this case, which are along the northwest/west-central FL coast from 06Z-12Z. ...Interior Pacific Northwest into the Northern Rockies... A negatively tilted shortwave trough is forecast to progress across the Pacific Northwest on Tuesday. Moderate mid-level flow and moisture will spread eastward ahead of this wave across ID and into western MT. Resulting combination of a deeply mixed boundary layer, increasing mid-level moisture, and strengthening ascent is expected to result in afternoon/evening thunderstorm development. 20 to 30 kt of effective shear will help organize some updrafts, with high cloud bases and steep low-level lapse rates supporting the potential for strong outflow. An instance or two of hail is possible as well. ...Great Lakes/OH Valley... A cold front is forecast move southeastward across the Great Lakes and parts of the Midwest/OH Valley, in tandem with an eastward-moving upper trough. Dewpoints will likely be in the upper 50s and low 60s from IL into IN and MI ahead of this front, but mid-level temperatures will be relatively warm, limiting buoyancy and updraft strength/duration. Damaging gusts would be possible with any deep, sustained updrafts, but the overall probability of occurrence currently appears low. ...Appalachians... Scattered thunderstorms should develop across parts of the southern/central Appalachians Tuesday afternoon, as modest ascent associated with an upper trough moving Quebec and the Upper Great Lakes/OH Valley glances the region. Modest deep-layer vertical shear is anticipated amid the southwesterly mid-level flow stretching across the region, supporting potential updraft organization. Even so, poor lapse rates should limit instability and overall updraft strength. A generally multicellular, outflow-dominant storm mode is anticipated, and the potential for a damaging gust or two exists within any bowing segments. However, overall severe coverage is expected to remain too low to include severe probabilities. ..Mosier.. 08/28/2023 Read more

No watches are valid as of Sun Aug 27 22:22:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0454 PM CDT Sun Aug 27 2023 Valid 291200Z - 041200Z ...D3/Tue - D4/Wed - Southern Plains... Dry and breezy conditions will develop in the northerly flow between the high pressure in the High Plains and the tropical system in the Gulf of Mexico. Thunderstorms Saturday and Sunday likely provided wetting rains for some locations, but others will still have exceptionally dry fuels. ......D3/Tue - Montana... There will be some potential for critical fire weather conditions on Tuesday across portions of northern Montana. Pre-frontal winds are expected to be strongest across portions of north-central Montana where minimal precipitation fell last week. Therefore, 40 percent probabilities have been added for the increasing threat for elevated to critical fire weather conditions across north-central Montana on Tuesday. ...D3/Tue - D4/Wed - Northwest... A negatively tilted mid-level trough will move across the Pacific Northwest on Tuesday. This will bring numerous thunderstorms, particularly across Washington. PWAT values are expected to be around 1 inch with storms likely more wet. However, storm speeds will be in excess of 30 mph, which could increase the threat for dry thunderstorms somewhat. Nonetheless, no dry thunderstorm probabilities have been added due to the questions regarding storm wetness and only marginally dry fuels east of the Cascades where storms may be more dry. As this trough advances east, some breezy conditions are expected in the Columbia Basin. The significant moisture surge with this system may keep relative humidity higher and thus keep the fire weather threat somewhat more subdued than otherwise may be expected. At this time, no 40 percent probabilities have been added as relative humidity is forecast to stay 30%+ where fuel are critically dry. ..Bentley.. 08/27/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2057 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHERN MS AND LA INTO FAR EAST TX
Mesoscale Discussion 2057 NWS Storm Prediction Center Norman OK 0345 PM CDT Sun Aug 27 2023 Areas affected...portions of southern MS and LA into far east TX Concerning...Severe potential...Watch unlikely Valid 272045Z - 272245Z Probability of Watch Issuance...5 percent SUMMARY...Scattered thunderstorms with isolated downburst winds are possible this afternoon/early evening. DISCUSSION...Across portions of the lower MS Valley and central Gulf Coast, afternoon thunderstorms were observed developing along a frontal boundary/remnant outflow. Strong diurnal heating has eroded inhibition with 1500-2000 J/kg of MLCAPE supporting occasional stronger updrafts. Deep-layer vertical shear across much of the region is exceedingly weak at generally less than 10-15 kt. This will support multi-cellular, pulse convection as the primary storm mode. Weak surface flow is also not expected to support much cold pool propagation and storm conglomeration seems unlikely. Thus, the primary severe risk will be tied to individual pulse downdrafts as storms collapse. Greater than 1000 J/kg of DCAPE and steep low-level lapse rates from very warm temperatures may support stronger outflow winds with sporadic damaging gusts. With little in the way of storm organization or longevity expected, a WW appears very unlikely. ..Lyons/Thompson.. 08/27/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MOB...JAN...LIX...LCH...SHV...HGX...FWD... LAT...LON 30928898 31268945 31629039 31919184 32109304 32259432 32229507 31889558 31469563 31109535 30429450 30209361 29989193 29839020 30248937 30418909 30928898 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Sun Aug 27 2023 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM CENTRAL TX INTO THE CAROLINAS... ...SUMMARY... Thunderstorms capable of locally damaging winds are possible mainly this afternoon and early evening spanning parts of Texas to the Carolinas. ...20Z Update... Overall forecast remains unchanged. Scattered thunderstorms will continue throughout the afternoon into this evening from central TX across the Southeast into the Carolinas. Vertical shear is weak, but steep low-level lapse rates and ample low-level moisture could still support isolated damaging wind gusts. Scattered thunderstorms continue to develop from southeast WY into eastern CO/NM. MLCAPE is generally 500 to 1000 J/kg amid 20 to 30 kt of effective bulk shear, contributing to the potential for a few storms capable of producing hail and/or damaging gusts. Coverage is still expected to be too low to introduce any wind/hail areas. ..Mosier.. 08/27/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Aug 27 2023/ ...TX to the Carolinas this afternoon/early evening... A cold front will continue to sag slowly southward from central TX to the Ark-La-Miss and the Carolinas. The effective front is marked by outflow from northwest AL across central MS to northern LA, in association with an MCV that is moving south-southeastward over northwest MS. Away from ongoing convection/cloud debris, strong surface heating will drive MLCAPE values of 1500-3000 J/kg with minimal convective inhibition, which will allow scattered thunderstorm development along the front and mesoscale boundaries/terrain circulations. Steep low-level lapse rates and DCAPE of 750-1250 J/kg will support the potential for isolated wind damage with downbursts, in an environment of weak vertical shear. ...Central/southern High Plains this afternoon/evening... Residual low-level moisture and weak upslope flow will support scattered thunderstorms this afternoon from southeast WY to eastern CO and eastern NM. Buoyancy will remain rather modest (MLCAPE of 1000-1500 J/kg) and there will be sufficient vertical shear for semi-organized storms with the potential for isolated strong gusts and some hail. However, the overall severe potential appears to be too low to warrant the addition of wind/hail outlook areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Sun Aug 27 2023 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM CENTRAL TX INTO THE CAROLINAS... ...SUMMARY... Thunderstorms capable of locally damaging winds are possible mainly this afternoon and early evening spanning parts of Texas to the Carolinas. ...20Z Update... Overall forecast remains unchanged. Scattered thunderstorms will continue throughout the afternoon into this evening from central TX across the Southeast into the Carolinas. Vertical shear is weak, but steep low-level lapse rates and ample low-level moisture could still support isolated damaging wind gusts. Scattered thunderstorms continue to develop from southeast WY into eastern CO/NM. MLCAPE is generally 500 to 1000 J/kg amid 20 to 30 kt of effective bulk shear, contributing to the potential for a few storms capable of producing hail and/or damaging gusts. Coverage is still expected to be too low to introduce any wind/hail areas. ..Mosier.. 08/27/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Aug 27 2023/ ...TX to the Carolinas this afternoon/early evening... A cold front will continue to sag slowly southward from central TX to the Ark-La-Miss and the Carolinas. The effective front is marked by outflow from northwest AL across central MS to northern LA, in association with an MCV that is moving south-southeastward over northwest MS. Away from ongoing convection/cloud debris, strong surface heating will drive MLCAPE values of 1500-3000 J/kg with minimal convective inhibition, which will allow scattered thunderstorm development along the front and mesoscale boundaries/terrain circulations. Steep low-level lapse rates and DCAPE of 750-1250 J/kg will support the potential for isolated wind damage with downbursts, in an environment of weak vertical shear. ...Central/southern High Plains this afternoon/evening... Residual low-level moisture and weak upslope flow will support scattered thunderstorms this afternoon from southeast WY to eastern CO and eastern NM. Buoyancy will remain rather modest (MLCAPE of 1000-1500 J/kg) and there will be sufficient vertical shear for semi-organized storms with the potential for isolated strong gusts and some hail. However, the overall severe potential appears to be too low to warrant the addition of wind/hail outlook areas. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0154 PM CDT Sun Aug 27 2023 Valid 281200Z - 291200Z No changes were made to the Elevated area on Monday across Texas and southern Oklahoma. Some windy conditions are expected through the Cascade gaps tomorrow afternoon and evening. However, this is expected to be accompanied by a marine push which should keep relative humidity high enough to avoid more significant fire weather concerns. ..Bentley.. 08/27/2023 .PREV DISCUSSION... /ISSUED 1225 AM CDT Sun Aug 27 2023/ ...Synopsis... On Monday, post frontal northerly winds will filter in a dry continental air mass across southern Oklahoma/north-central Texas. Sustained winds around 10-15 mph will overlap relative humidity around 20-25 percent. Fuels within this region are critically dry, though there is a chance for wetting rainfall with shower and thunderstorm activity on Sunday. Widespread rainfall heavy enough to alter status of fuels is unlikely, which will keep Elevated to near Critical conditions possible. An Elevated delineation was maintained for now and will be adjusted as needed based on rainfall trends on Sunday. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Sat Aug 26 22:21:01 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0449 PM CDT Sat Aug 26 2023 Valid 281200Z - 031200Z ...D3/Mon - D5/Wed - Southern Plains... Dry and breezy post-frontal flow in the southern Plains will lead to an extended period of elevated to potentially critical fire weather conditions in a region with ongoing extreme to exceptional drought. Thunderstorms today and Sunday may improve fuel state in some localized regions, but it is not expected to be widespread enough to have a significant impact on fuel receptiveness. ...D3/Mon - D5/Wed - Northwest... A negatively tilted mid-level trough will start to proceed inland across the Pacific Northwest on Monday. As this occurs, some thunderstorms will be possible across the Cascade crests during the day and much of western Washington overnight. PWAT values are expected to be around 1 inch with storms likely more wet. However, storm speeds will be in excess of 30 mph, which could increase the threat for dry thunderstorms somewhat. As this trough advances east, some breezy conditions are expected in the higher terrain on the western slopes of the Cascades and through the Cascade gaps. The significant moisture surge with this system may keep relative humidity higher and thus keep the fire weather threat somewhat more subdued than otherwise may be expected. These dry and breezy conditions will expand into the Great Basin and Columbia Basin on Tuesday and Wednesday. At this time, no 40 percent probabilities have been added as relative humidity is forecast to stay 30%+ where fuel are critically dry. ...D4/Tue - D5/Wed - Montana... There will be some potential for critical fire weather conditions on Tuesday on Wednesday across portions of northern Montana both ahead and behind the surface front. Fuels had moistened recently in the area but are starting to dry once again. If fuels continue to dry and winds/relative humidity continue to show worsening conditions, a 40% probability may be needed in later outlooks. ..Bentley.. 08/26/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2056 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EASTERN OREGON AND SOUTH CENTRAL IDAHO
Mesoscale Discussion 2056 NWS Storm Prediction Center Norman OK 0332 PM CDT Sat Aug 26 2023 Areas affected...portions of eastern Oregon and south central Idaho Concerning...Severe potential...Watch unlikely Valid 262032Z - 262230Z Probability of Watch Issuance...20 percent SUMMARY...Isolated high-based strong to severe storms are possible this afternoon and evening. Damaging gusts and small hail are possible with the strongest storms. A WW is unlikely. DISCUSSION...Across the northern Intermountain west, broad southerly flow ahead of a mid-level trough was transporting monsoon moisture northward into portions of eastern OR and southern ID. At the nose of this surge, visible imagery showed new thunderstorm development ongoing across parts of far northern NV/UT into southern ID. Clear skies have allowed for strong diurnal heating and destabilization with MUCAPE of 1000-15000 J/kg observed via SPC mesoanalysis. As remaining inhibition is removed ahead of the northward lifting trough, thunderstorms should continue to develop and mature through the afternoon. Vertical shear of 30-35 kt should support some storm organization/longevity into organized multicells and perhaps transient supercell structures. Likely high based with LCLs near or exceeding 2500 m, the primary risk will be damaging outflow gusts from the more persistent storms. However, some small accumulating hail may also be possible given relatively steep mid-level lapse rates and the presence of a few longer-lived, and stronger updrafts. The primary uncertainty with regard to the severe threat this afternoon/evening is the coverage of severe storms. While a few stronger updrafts are likely to evolve, broader synoptic forcing for ascent is still relatively modest. This suggests a generally more isolated threat related to individual storm evolution through much of the day. Given this uncertainty, a new WW appears unlikely, but convective trends will be monitored. ..Lyons/Thompson.. 08/26/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PIH...MSO...BOI...PDT... LAT...LON 44541421 43601328 43111328 42791353 42581434 42551518 42791597 43481753 43911823 44211862 44801846 45041784 45041672 44941587 44541421 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Sat Aug 26 2023 Valid 262000Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS THE SOUTHEAST MO/NORTHEAST AR VICINITY... ...SUMMARY... Occasional damaging gusts will be possible this afternoon and evening across southeast Missouri/northeast Arkansas and vicinity, with more isolated strong winds possible into the southern Appalachians and across parts of Idaho and Oregon. ...20Z Update... Overall, no changes are needed to the previous outlook. More forecast details provided below and in the appended outlook. ...Southeast MO/northeast AR area this afternoon/evening... As mentioned in recently issued MCD #2054, thunderstorms capable of producing isolated to scattered damaging winds will become increasingly possible later this afternoon across parts of southern MO/IL, northern AR, and western KY/TN. Strong heating and large PW will support a threat of at least isolated wet microbursts as these storms sag southward through the afternoon. ...Southern Appalachians into the Central Carolinas... As discussed in MCD #2055, strong heating ahead of an eastward-progressing MCV, along with typical diurnal terrain circulations should support additional thunderstorm development through this afternoon. Moderate buoyancy (1000-2000 J/kg of MLCAPE) and fairly steep low-level lapse rates should support occasional strong updrafts. As result, isolated strong to severe storms, with the potential for a few damaging downburst gusts, will be possible this afternoon and evening across the region. ...Southern ID/Eastern OR... Thunderstorm development has already be observed across the region ahead of the approaching speed max, with additional storm development still possible this afternoon/evening. Modest vertical shear could help organize updrafts, with high cloud bases and steep low-level lapse rates contributing to the potential for isolated strong/severe outflow. ..Mosier.. 08/26/2023 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Aug 26 2023/ ...Southeast MO/northeast AR area this afternoon/evening... The persistent midlevel high continues to slowly weaken over the southern Plains, while a series of MCVs rotate around the northern and eastern periphery of the high, from KS to the southern Appalachians. The most pronounced MCV is now moving southeastward over northwest MO and will interact with the unstable warm sector this afternoon in the vicinity of southeast MO, where additional thunderstorm development is expected south of the ongoing convection near Saint Louis. Daytime heating in cloud breaks and boundary-layer dewpoints in the mid 70s will result in MLCAPE of 2500-3000 J/kg, and lapse rate profiles will also favor strong downdrafts (DCAPE of 1000-1500 J/kg). Primarily multicell clusters are expected as a result of weak vertical shear in the warm sector ahead of the MCV. Damaging outflow winds will be the main severe threat from mid-late afternoon into this evening. ...Southern ID/eastern OR this afternoon/evening... A weak mid-upper speed max is translating northward around the western periphery of the ridge from the southern Plains into the Rockies. A band of ascent and midlevel moisture, coincident with surface heating in cloud breaks, will support scattered thunderstorm development this afternoon into this evening. Typical inverted-V profiles and some modest enhancement to deep-layer vertical shear will support somewhat organized cells (and perhaps a low-end supercell) capable of producing isolated strong-severe outflow gusts. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 26 2023 Valid 271200Z - 281200Z Added an Elevated delineation for portions of central and northern Texas and southwest Oklahoma. Given the extreme to exceptional drought ongoing, northerly winds behind the cold front (15 gust 25 mph) may be sufficiently strong to support an increased fire weather threat despite only marginally dry relative humidity (30-35 percent). Elsewhere, the forecast remains on track with relatively benign fire weather conditions. ..Bentley.. 08/26/2023 .PREV DISCUSSION... /ISSUED 0148 AM CDT Sat Aug 26 2023/ ...Synopsis... On Sunday, the central/western US upper-level ridge will shift westward across the Four Corners. A cold front will sag southward across the Southern Plains bringing a shift to northerly flow, cooling temperatures, and rain and thunderstorm chances. While this looks like a better chance for more widespread wetting rainfall across Central Texas and southern Louisiana, more appreciable totals will likely remain somewhat localized. Due to the extremely critical nature of fuels, areas that receive very little rainfall will likely not see much change in fuel status and potential for new lightning starts. Humidity will increase with cooler temperatures behind the front. Relative humidity will be around 20 percent across central Texas ahead of the passing front, which may allow for some locally Elevated conditions. Overall, the threat is too centralized for inclusion of any Elevated highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Fri Aug 25 22:26:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0442 PM CDT Fri Aug 25 2023 Valid 271200Z - 021200Z ...D5/Tue-D6/Wed - Texas into Louisiana... A cold front will move through the southern Plains on Sunday. In the wake of this cold front, a dry, continental airmass will move into place across much of the Plains and into parts of the Southeast. The lowest RH is expected across the regions of severe to exceptional drought across portions of Texas and Louisiana. Initially, winds behind the front will be weak on Sunday and Monday. However, on Tuesday and Wednesday, northerly/northeasterly winds will strengthen as the pressure gradient tightens between High Pressure in the central High Plains and a developing tropical system in the Gulf of Mexico. Elevated to potentially critical conditions are likely on Tuesday and Wednesday amid these strengthening post-frontal winds. ...D5/Tue - Northwest... On Tuesday, a strong mid-level trough will move across the Northwest. This system will bring the potential for thunderstorms. Any thunderstorms in western Oregon and Washington could have some concern for new lightning starts. However, less favorable fuels east of the Cascades, combined with 1+ inch PWAT values should mitigate the threat somewhat. In addition, strong winds are expected to develop as the pressure gradient tightens across the Cascades. The strongest winds will likely be in the higher terrain of the Cascades, in the Cascade gaps and in the Columbia Basin. At this time it does not appear relative humidity will be low enough, particularly where fuels are dry, to support Critical probabilities. ...D6/Wed - Northern Rockies... On Wednesday, the strong mid-level jet will move east and affect a large portion of Montana. Dry and breezy conditions are expected with some critical conditions likely. However, fuels in this area are not that favorable for large fire spread. Some drying of fuels may occur by then, and a greater threat may materialize, but for now there is enough uncertainty about fuels to preclude any Critical probabilities. ..Bentley.. 08/25/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2048 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN KS INTO EXTREME SOUTHERN NE
Mesoscale Discussion 2048 NWS Storm Prediction Center Norman OK 0354 PM CDT Fri Aug 25 2023 Areas affected...Western KS into extreme southern NE Concerning...Severe potential...Watch unlikely Valid 252054Z - 252300Z Probability of Watch Issuance...20 percent SUMMARY...Storms capable of hail and isolated severe gusts may increase through late afternoon. DISCUSSION...Storms are gradually increasing in coverage this afternoon from southwest NE into northwest KS, near/north of a surface low near the CO/KS state line. Thus far, the strongest storms have been to the cool side of a surface boundary across extreme southwest NE, where otherwise-weak deep-layer shear is slightly stronger due to surface northeasterly winds. Occasional strong multicells in this region may pose an isolated hail and severe gusts threat through the afternoon. Additional deepening cumulus is noted within the hot/well-mixed environment south of the surface boundary into a larger portion of western KS. As storms deepen/mature within this regime, inverted-V profiles will support a threat of isolated severe downbursts through late afternoon. Outflow consolidation may eventually result in a loosely organized cluster, but the short-term threat is expected to remain disorganized and rather isolated, rendering watch issuance unlikely. ..Dean/Thompson.. 08/25/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TOP...ICT...GID...LBF...DDC...GLD... LAT...LON 37900120 39040184 39940165 40510114 40219778 39559755 39019775 38399831 38039963 37980047 37900120 Read more

MD 2047 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHERN IL/IN
Mesoscale Discussion 2047 NWS Storm Prediction Center Norman OK 0325 PM CDT Fri Aug 25 2023 Areas affected...Parts of southern IL/IN Concerning...Severe potential...Watch unlikely Valid 252025Z - 252230Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe storms are possible later this afternoon into the evening, with a threat of locally damaging wind and perhaps some hail. DISCUSSION...A strong thunderstorm has recently developed across south-central IL, with an increasing cumulus field noted farther east along a surface boundary into southeast IL and southern IN. Strong to extreme buoyancy has developed within a very hot/moist environment, with MLCAPE in the 3000-4500 J/kg range per recent mesoanalyses and also noted regionally on the 18 UTC ILN sounding. While deep-layer shear is rather weak (with effective shear generally less than 25 kt), the favorable buoyancy will support a threat of isolated hail and localized downbursts with any sustained development through the afternoon. Storm coverage through the afternoon remains somewhat uncertain, with generally limited large-scale ascent and weak convergence along the boundary. With the threat expected to remain somewhat isolated, watch issuance in the short-term is considered unlikely. ..Dean/Thompson.. 08/25/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILN...LMK...IND...PAH...ILX...LSX... LAT...LON 39808935 39378766 39558605 39338490 38848482 38178595 38078740 38458936 38918970 39128986 39808935 Read more