SPC Apr 10, 2023 1730 UTC Day 2 Convective Outlook

2 years 5 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1209 PM CDT Mon Apr 10 2023 Valid 111200Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible over the Florida Peninsula and Pacific Northwest as well as from the Texas Hill Country to the western Gulf Coast on Tuesday. Severe thunderstorms are not expected. ...Synopsis... A closed upper low will persist near the northwest Gulf coast vicinity on Tuesday. Surface high pressure centered over the TN Valley will generally keep deeper Gulf moisture offshore, except across the TX Coast into far southern LA where dewpoints in the 50s to near 60 F will be in place. Weak buoyancy in the presence of this modest boundary-layer moisture will support isolated thunderstorms near the northwest Gulf coast vicinity westward to the Edwards Plateau/TX Hill Country vicinity. Limited instability and weak vertical shear will preclude severe potential. Additional isolated lightning flashes are possible across south FL where 60s F dewpoints will remain in place. Modest diurnal destabilization will support isolated thunderstorms during the afternoon. Across the Pacific Northwest, a strong upper shortwave trough will move onshore and shift eastward to the northern Rockies. Cooling aloft and steep midlevel lapse rates will support isolated thunderstorms across parts of northwest OR, much of WA and into northern ID/far northwest MT. ..Leitman.. 04/10/2023 Read more

SPC Day 1 Fire Weather Outlook

2 years 5 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Mon Apr 10 2023 Valid 101700Z - 111200Z ...NO CRITICAL AREAS... The previous forecast remains valid with no changes. Fire-weather concerns are low. ..Lyons.. 04/10/2023 .PREV DISCUSSION... /ISSUED 0109 AM CDT Mon Apr 10 2023/ ...Synopsis... Surface high pressure will be the dominant feature across much of the lower 48 today as an upper-level ridge continues to shift east. A strong upper-level trough will impact the Northwest late in the period. Winds in some parts of the Plains will increase during the evening/overnight, as surface low pressure develops in the northern High Plains in response to the trough. However, only light winds are expected over areas of dry fuels, and fire weather concerns will remain minimal. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Apr 10, 2023 1630 UTC Day 1 Convective Outlook

2 years 5 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Mon Apr 10 2023 Valid 101630Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST KS THROUGH WEST-CENTRAL OK... ...SUMMARY... Scattered severe hail and isolated thunderstorm gusts are expected this afternoon from northwest Texas across central Oklahoma to southeastern Kansas. ...Northwest TX to southeast KS... Along the eastern periphery of an amplified large-scale ridge encompassing the western CONUS, a midlevel speed maximum -- embedded in northerly flow aloft -- will dive southward and gradually strengthen across the central and southern Plains into this evening. While the low-level mass response accompanying this feature will be minimal, a northeast-southwest-oriented surface trough (and accompanying wind shift) is already in place from east-central KS southwestward through west-central OK into northwest TX this morning. In response to the strengthening northerlies aloft, this feature will move slightly south-southeastward today, remaining over the central/southern Plains during the afternoon/evening hours. Along/south of the surface trough, lower/middle 50s surface dewpoints and efficient boundary-layer heating/mixing should support widely scattered to scattered thunderstorm development along the surface trough/wind shift in the 19-22Z time frame -- aided by subtle ascent accompanying the approaching speed maximum. Weak south-southeasterly low-level flow veering to deep/stronger northerly flow aloft will yield long/mostly straight north-south oriented hodographs supportive of splitting supercell structures. Given a steep low/mid-level lapse rate environment and the potential for maintained semi-discrete cells/clusters, scattered large hail and severe gusts are possible with the longer-lived storms into the evening hours. Confidence in a higher concentration of severe hail (some approaching 2 inch) is highest across portions of northern and western OK and southeast KS, and a Slight Risk has been added to account for this. In addition, given enhanced surface vorticity along the wind shift, slow-moving storms developing atop the boundary from southeast/south-central KS to north-central OK could produce a landspout or two (aided by favorable 0-3 km CAPE). ...Southern FL... As the left-exit region of an upper-level jet streak overspreads deep tropospheric moisture and modest deep-layer lapse rates this afternoon, long/straight hodographs could favor a couple loosely organized storms capable of strong winds this afternoon. However, the potential for organized/long-lived storms appears too low for severe probabilities at this time. ..Weinman/Guyer.. 04/10/2023 Read more

SPC Apr 9, 2023 2000 UTC Day 1 Convective Outlook

2 years 5 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0242 PM CDT Sun Apr 09 2023 Valid 092000Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorm gusts and large hail are possible across portions of the southern High Plains this afternoon and evening. ...20z Update - Southern Plains... The previous forecast remains on track and no changes have been made with the 20z update. Isolated thunderstorms have developed this afternoon within the Marginal risk area, with one severe-warned storm currently across southwest OK. These storms may briefly become severe, producing strong gusts and near-one inch hail. Severe potential is expected to remain sporadic/marginal. ..Leitman.. 04/09/2023 .PREV DISCUSSION... /ISSUED 1128 AM CDT Sun Apr 09 2023/ ...Southern High Plains... A low-amplitude, southern-stream shortwave trough will continue advancing slowly eastward over the central/southern High Plains today, before gradually weakening and becoming absorbed into a more-pronounced northern-stream midlevel trough this evening/overnight. As this feature continues eastward, modestly enhanced midlevel westerly flow will gradually veer to northwesterly by this evening, while a related surface lee trough remains nearly stationary over the High Plains. East of the lee trough, two weak mesoscale lows have developed in response to early-morning/ongoing convection -- one over the TX Panhandle and the other near the TX South Plains. Along the southern/eastern peripheries of the northern mesoscale low/outflow boundary, lower 50s surface dewpoints are spreading northward in conjunction with filtered diurnal heating. As MLCINH erodes, additional surface-based convection should focus along this boundary over the southern TX Panhandle into far southwest OK this afternoon. Steep midlevel lapse rates and elongated mid/upper-level hodographs should favor a couple loosely organized, splitting supercell structures capable of large hail and locally severe gusts. Similarly, diurnal destabilization/steepening low-level lapse rates along/ahead of the southern mesoscale low/outflow boundary should favor additional convective development this afternoon. Given the steep deep-layer lapse rate environment and long/generally straight hodographs (30-40 kt of effective shear), isolated large hail is expected -- especially with the early/cellular development. From the afternoon into the evening/overnight hours, convection will generally spread/expand southeastward as midlevel flow veers on the backside of the weakening shortwave trough. Continued outflow generation amid slightly stronger deep-layer shear could support localized upscale growth/convective clustering and an increasing potential for severe gusts. Eventually, convection will impinge on increasing nocturnal boundary-layer stability and a residual midlevel capping inversion with southward extent, with a corresponding decrease in severe potential during the overnight hours. Read more

SPC MD 499

2 years 5 months ago
MD 0499 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF THE TEXAS PANHANDLE INTO SOUTHWEST OKLAHOMA AND NORTHWEST TEXAS
Mesoscale Discussion 0499 NWS Storm Prediction Center Norman OK 0120 PM CDT Sun Apr 09 2023 Areas affected...parts of the Texas Panhandle into southwest Oklahoma and northwest Texas Concerning...Severe potential...Watch unlikely Valid 091820Z - 092145Z Probability of Watch Issuance...20 percent SUMMARY...Scattered storms are likely to form after 20Z, and a few storms may produce hail over 1.00" diameter and locally strong wind gusts. DISCUSSION...Visible imagery shows strong heating over the panhandles and into much of the South Plains and northwest TX, the exception being the eastern TX Panhandle into western OK in association with a batch of showers and cirrus. CU is beginning to form within the surface trough from eastern NM into the TX Panhandle, with weak wind convergence. GPS PW sensors show a plume of 0.80-0.90" PWAT from northwest TX into the eastern TX Panhandle and South Plains, where dewpoints remain in the 50s F. The cold midlevel trough is currently over the area, which when combined with heating, continues to steepen lapse rates. Scattered storms are expected to form both along the weak convergence zone and farther east into the moist plume, where differential heating near the outflow/clouds exists. The steep lapse rates and sufficient deep-layer shear will favor a few storms producing hail around 1.00-1.50" diameter, especially later in the day. Mixed storm modes are expected, with locally strong wind gusts with the outflows as well. ..Jewell/Guyer.. 04/09/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OUN...LUB...AMA... LAT...LON 35249935 34619936 33989952 33639978 33450029 33460097 33930147 34600195 35420199 35850150 36300095 36460039 36149982 35899954 35249935 Read more

SPC Day 2 Fire Weather Outlook

2 years 5 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0114 PM CDT Sun Apr 09 2023 Valid 101200Z - 111200Z ...NO CRITICAL AREAS... The previous forecast remains on track. Recent guidance continues to show low probability for elevated or critical fire weather conditions over areas with receptive fuels. See the previous discussion for additional details. ..Moore.. 04/09/2023 .PREV DISCUSSION... /ISSUED 0153 AM CDT Sun Apr 09 2023/ ...Synopsis... Upper-level ridging will continue to shift eastward on Monday. A stronger mid-level trough will impact the Pacific Northwest. At the surface, a high-pressure center in the Southeast will remain in place. In the northern Plains, a low will develop in response the approaching trough. Surface winds in the Plains will generally be light for much of day, with an increase during the evening/overnight when RH will have increased. Fire weather concerns will be minimal. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Apr 9, 2023 1730 UTC Day 2 Convective Outlook

2 years 5 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sun Apr 09 2023 Valid 101200Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated to scattered thunderstorms are possible across portions of the southern Plains as well as the Florida Peninsula. Severe thunderstorms are not currently anticipated. ...Synopsis... A weak shortwave trough will migrate east across the central/southern Plains and Mid to Lower-MS Valley on Monday. Boundary-layer moisture will remain modest as surface high pressure over the eastern U.S. and over the Rockies suppresses stronger Gulf return flow. Nevertheless, mainly 50s F (to low 60s over central/south TX) dewpoints beneath modest midlevel lapse rates and some diurnal heating will support thunderstorm development from southeast KS/southwest MO into OK/TX through the period. Deep-layer flow will remain light, but directional shear will support effective shear magnitudes around 25-35 kt. A couple of strong storms may produce small hail or gusty winds across parts of central OK into central TX. Weak large-scale ascent coupled with modest instability and modest shear will likely limit longevity of any better organized cells, and severe potential appears too low to include probabilities at this time. Moderate northeasterly low/midlevel flow is forecast across the FL Peninsula on Monday. Early day thunderstorms along the east coast will shift/develop west/southwest through the afternoon. MLCAPE to around 1500 J/kg and modest effective shear may support some stronger cells/clusters capable of gusty winds and small hail across southern and central portions of the Peninsula. Warming around 700 mb and poor lapse rates noted in forecast soundings may inhibit a low-end severe threat, precluding probabilities at this time. ..Leitman.. 04/09/2023 Read more

SPC Apr 9, 2023 1630 UTC Day 1 Convective Outlook

2 years 5 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Apr 09 2023 Valid 091630Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe thunderstorm gusts and large hail are possible across portions of the southern High Plains this afternoon and evening. ...Southern High Plains... A low-amplitude, southern-stream shortwave trough will continue advancing slowly eastward over the central/southern High Plains today, before gradually weakening and becoming absorbed into a more-pronounced northern-stream midlevel trough this evening/overnight. As this feature continues eastward, modestly enhanced midlevel westerly flow will gradually veer to northwesterly by this evening, while a related surface lee trough remains nearly stationary over the High Plains. East of the lee trough, two weak mesoscale lows have developed in response to early-morning/ongoing convection -- one over the TX Panhandle and the other near the TX South Plains. Along the southern/eastern peripheries of the northern mesoscale low/outflow boundary, lower 50s surface dewpoints are spreading northward in conjunction with filtered diurnal heating. As MLCINH erodes, additional surface-based convection should focus along this boundary over the southern TX Panhandle into far southwest OK this afternoon. Steep midlevel lapse rates and elongated mid/upper-level hodographs should favor a couple loosely organized, splitting supercell structures capable of large hail and locally severe gusts. Similarly, diurnal destabilization/steepening low-level lapse rates along/ahead of the southern mesoscale low/outflow boundary should favor additional convective development this afternoon. Given the steep deep-layer lapse rate environment and long/generally straight hodographs (30-40 kt of effective shear), isolated large hail is expected -- especially with the early/cellular development. From the afternoon into the evening/overnight hours, convection will generally spread/expand southeastward as midlevel flow veers on the backside of the weakening shortwave trough. Continued outflow generation amid slightly stronger deep-layer shear could support localized upscale growth/convective clustering and an increasing potential for severe gusts. Eventually, convection will impinge on increasing nocturnal boundary-layer stability and a residual midlevel capping inversion with southward extent, with a corresponding decrease in severe potential during the overnight hours. ..Weinman/Guyer.. 04/09/2023 Read more

SPC Apr 8, 2023 2000 UTC Day 1 Convective Outlook

2 years 5 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Sat Apr 08 2023 Valid 082000Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong thunderstorms are possible across northern Florida through early evening; however, organized severe weather appears unlikely. ...20z Update... Minor adjustments have been made to the 10 percent general thunder line across the Southeast and in parts of the southern/central High Plains vicinity based on latest observations and forecast guidance trends. Severe storms are not expected through tonight. ..Leitman.. 04/08/2023 .PREV DISCUSSION... /ISSUED 1128 AM CDT Sat Apr 08 2023/ ...FL Panhandle through northern FL... A low-amplitude midlevel shortwave trough over the TN Valley, preceded by 30-40-kt southwesterly 500-mb flow, will continue eastward across the Southeast today. In the low-levels, an east-west-oriented quasi-stationary surface boundary extends across northern FL into the FL Panhandle, with a weak frontal wave (currently near the western FL Panhandle) evolving eastward along the boundary. Immediately ahead of the frontal wave, a broken band of thunderstorms will continue eastward across the FL Big Bend this afternoon. While 30-40 kt of effective shear could promote an embedded strong storm or two with this activity, widespread cloud coverage amid poor deep-layer lapse rates (and related weak instability) should generally limit the risk of organized surface-based storms over land. As large-scale ascent accompanying the shortwave trough glances northern FL this afternoon, additional thunderstorm development should focus along the quasi-stationary surface boundary and east coast sea breeze. Despite filtered diurnal heating amid upper 60s/lower 70s dewpoints, poor mid/upper-level lapse rates and marginal buoyancy should still limit the severe threat. Nevertheless, a brief/loosely organized storm or two cannot be entirely ruled out given sufficient deep-layer shear -- especially along the intersection of the east coast sea breeze and east-west-oriented surface boundary this afternoon. Read more

SPC Day 2 Fire Weather Outlook

2 years 5 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 PM CDT Sat Apr 08 2023 Valid 091200Z - 101200Z ...NO CRITICAL AREAS... No changes are needed to the ongoing forecast. Drier solutions that have handled temperature/dewpoint trends well over the past 48 hours suggest that dry/windy conditions may emerge across portions of northeast IA into southern WI and adjacent areas of IL. However, recent fuel analyses and reports from regional offices indicate that fuels are not overly receptive to fire spread. ..Moore.. 04/08/2023 .PREV DISCUSSION... /ISSUED 0154 AM CDT Sat Apr 08 2023/ ...Synopsis... Quasi-zonal flow is expected to evolve into more amplified ridging across the West and Plains on Sunday. A weak High Plains lee trough will fill through the day as surface high pressure becomes the predominant feature across much of the U.S. This pattern will favor generally light winds across areas of dry fuels. Fire weather concerns will be minimal. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Apr 8, 2023 1730 UTC Day 2 Convective Outlook

2 years 5 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1146 AM CDT Sat Apr 08 2023 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated to widely scattered thunderstorms are possible from the Texas Permian Basin into the central Plains Sunday afternoon and evening. Isolated thunderstorms are possible across the Florida Peninsula as well. ...TX/OK/KS Vicinity... A series of weak mid/upper-level shortwave trough will migrate across the Plains on Sunday; one over the northern Plains to the upper Great Lakes, and another over the central/southern Plains vicinity. At the surface, high pressure centered over the lower Great Lakes/Northeast vicinity and encompassing much of the eastern half of the CONUS will limit Gulf return flow. Any deeper boundary-layer moisture is expected to remain over south TX despite modest southerly low-level flow across the southern/central Plains. A weak cold front/dryline is expected to be oriented from central NE into western KS and the eastern OK/TX Panhandles early in the day. The boundary will shift somewhat eastward through the day, before retreating westward during the evening/overnight. Strong heating and cooling aloft (leading to modest midlevel lapse rates) will support weak diurnal destabilization. While boundary-layer moisture will remain modest (generally low/mid 50s F), increasing midlevel moisture amid weak large-scale ascent and frontal convergence should support isolated thunderstorm development near the surface boundary from western KS into northwest OK and western TX. Deep-layer flow will remain generally weak through the period, but veering with height will result in modest effective shear. Small hail and gusty winds could accompany a stronger cell or two. However, longevity of stronger updrafts will be limited by overall lackluster thermodynamic and kinematic environment and severe potential appears too limited in aerial extent/time to include Marginal probabilities at this time. ..Leitman.. 04/08/2023 Read more

SPC Apr 8, 2023 1630 UTC Day 1 Convective Outlook

2 years 5 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sat Apr 08 2023 Valid 081630Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong thunderstorms are possible in the I-10 corridor across northern Florida through early evening; however, organized severe weather appears unlikely. ...FL Panhandle through northern FL... A low-amplitude midlevel shortwave trough over the TN Valley, preceded by 30-40-kt southwesterly 500-mb flow, will continue eastward across the Southeast today. In the low-levels, an east-west-oriented quasi-stationary surface boundary extends across northern FL into the FL Panhandle, with a weak frontal wave (currently near the western FL Panhandle) evolving eastward along the boundary. Immediately ahead of the frontal wave, a broken band of thunderstorms will continue eastward across the FL Big Bend this afternoon. While 30-40 kt of effective shear could promote an embedded strong storm or two with this activity, widespread cloud coverage amid poor deep-layer lapse rates (and related weak instability) should generally limit the risk of organized surface-based storms over land. As large-scale ascent accompanying the shortwave trough glances northern FL this afternoon, additional thunderstorm development should focus along the quasi-stationary surface boundary and east coast sea breeze. Despite filtered diurnal heating amid upper 60s/lower 70s dewpoints, poor mid/upper-level lapse rates and marginal buoyancy should still limit the severe threat. Nevertheless, a brief/loosely organized storm or two cannot be entirely ruled out given sufficient deep-layer shear -- especially along the intersection of the east coast sea breeze and east-west-oriented surface boundary this afternoon. ..Weinman/Guyer.. 04/08/2023 Read more

SPC Apr 7, 2023 2000 UTC Day 1 Convective Outlook

2 years 5 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Fri Apr 07 2023 Valid 072000Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... Isolated damaging gusts and hail remain possible across parts of the central Gulf Coast through early this evening. ...20Z Update... The western extent of the Marginal Risk has been trimmed based on current observations and short-term model trends. Weak north-northeasterly winds are occurring north of a cold front draped over the northwestern Gulf into far southeastern LA and coastal MS/AL. With just a weak surface mass response expected as a low-amplitude shortwave trough passes over the central Gulf Coast region, it appears unlikely that the front will return appreciably northward this afternoon/evening. Already limited severe potential should remain confined to where filtered daytime heating can overlap sufficient low-level moisture and deep-layer shear near the surface boundary. Overall severe threat still appears quite isolated, as the modest ascent associated with the minor mid-level perturbation should generally limit coverage of robust convection. ..Gleason.. 04/07/2023 .PREV DISCUSSION... /ISSUED 1123 AM CDT Fri Apr 07 2023/ ...Central Gulf Coast into the Southeast... Downstream of a broad, southern-stream upper trough over the southwestern CONUS, a belt of enhanced southwesterly midlevel flow extends across the central Gulf Coast into the Southeast. Morning water vapor imagery indicates an embedded, convectively augmented vorticity maximum near the upper TX coast, which will overspread the central Gulf Coast during the day today. Beneath the enhanced southwesterly flow aloft, a quasi-stationary surface boundary/warm front extends from the northwestern Gulf of Mexico east-northeastward across the Gulf Coast states, becoming a cold front into the Southeast. In response to the approaching vort max/shortwave trough, a frontal wave will evolve east-northeastward along the surface boundary this afternoon, with a modest low-level mass response expected over southern LA/MS. Within a plume of broad low-level warm-air advection and deep tropospheric moisture along/south of the surface boundary, numerous showers/thunderstorms are spreading eastward across the northwestern Gulf of Mexico and lower MS Valley this morning. While related widespread cloud coverage will limit diurnal heating/destabilization to an extent, rich boundary-layer moisture (upper 60s/lower 70s dewpoints) and at least filtered heating farther east should support surface-based thunderstorms along/south of the boundary this afternoon into the evening. Given the enhanced midlevel southwesterlies atop veering low-level flow (35-45 kt of effective shear), a few organized clusters/line segments and transient supercells will be possible. Isolated damaging gusts, sporadic large hail, and a brief tornado will all be possible. Farther east, ample diurnal heating of a moist air mass south of the cold front over central GA into far western SC will support isolated to widely scattered thunderstorms this afternoon. While low-level flow is very weak, 35-45 kt of effective shear could favor a loosely organized storm or two capable of strong gusts and/or marginal hail. However, most of this activity will likely be undercut by southward-spreading outflow and the cold front -- precluding severe probabilities. Read more

SPC Day 2 Fire Weather Outlook

2 years 5 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0203 PM CDT Fri Apr 07 2023 Valid 081200Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR THE CENTRAL PLAINS... A Critical risk area has been introduced for portions of the central Plains. Recent guidance continues to show high confidence in a swath of elevated to critical fire weather conditions from the NM/CO/OK/TX region to the mid-MO River Valley. Although hi-res ensemble guidance maintains marginal probabilities for critical conditions across the region (largely due to somewhat marginal RH), bias-corrected ensemble means suggest that RH values in the near 20% are probable. This conceptually matches well with a southerly dry return flow regime over the plains, which usually verify windier/drier than most guidance. The Critical risk area delineates where confidence in critical conditions is highest based on HRRR/RAP solutions (which handle boundary-layer mixing better in these scenarios) and the expected location of the 925-850 mb wind maximum, but localized critical conditions may emerge on the periphery of this zone. ..Moore.. 04/07/2023 .PREV DISCUSSION... /ISSUED 0141 AM CDT Fri Apr 07 2023/ ...Synopsis... Upper-level ridging will continue to shift east and flow will become more quasi-zonal. A shortwave trough will lift into the northern Plains. At the surface, high pressure will remain within the Great Lakes region. Another lee trough will develop in the central High Plains. The surface winds across western Kansas into eastern Nebraska will increase to 15-20 mph. There is again some uncertainty as to how low RH will fall, particularly with northward/eastward extent, but values around 20% are probable with some potential for values around 15%. At least elevated fire weather will be possible during the afternoon. Locally critical conditions may occur, but confidence in spatial/temporal overlap of the stronger winds with critically low RH remains low. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Apr 7, 2023 1730 UTC Day 2 Convective Outlook

2 years 5 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Fri Apr 07 2023 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated to scattered thunderstorms are possible Saturday into Saturday night across parts of the Southeast, as well as portions of the Rockies and adjacent southern/central Plains. Organized severe thunderstorms currently appear unlikely. ...Synopsis and Discussion... Appreciable low-level moisture will remain confined along/south of a front across the Southeast on Saturday. A weak mid-level perturbation embedded within modestly enhanced southwesterly flow aloft is forecast to move from the central Gulf Coast eastward into the western Atlantic through the period. A narrow corridor of weak instability may develop by Saturday afternoon over parts of north FL where filtered diurnal heating can occur. Weak low/mid-level winds and related shear should temper the overall severe threat and updraft organization. But, isolated gusty winds may still occur with any of the more robust thunderstorms that can form. Otherwise, additional elevated convection appears possible along/north of the front across a broader portion of the Southeast. Severe potential will likely remain quite low with this activity given weak MUCAPE forecast. Isolated lightning flashes may also occur across parts of the southern/central Rockies and adjacent Plains as another weak upper trough migrates eastward across these regions. ..Gleason.. 04/07/2023 Read more
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