SPC Day 1 Fire Weather Outlook

3 years 4 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0918 AM CST Thu Mar 10 2022 Valid 101700Z - 111200Z Shifted the risk area into southeast Arizona and trimmed the eastern extent of the elevated area based on morning frontal position and expected eastward movement of the front/dryline this afternoon. ..Bentley.. 03/10/2022 .PREV DISCUSSION... /ISSUED 1247 AM CST Thu Mar 10 2022/ ...Synopsis... An amplifying mid-level trough, embedded in the larger scale cyclonic upper flow regime, will impinge on the southern Rockies today, supporting surface low development across central New Mexico, and encouraging dry and windy conditions across southern New Mexico into far west Texas. Elevated highlights have been introduced where 15-25 mph sustained west-southwesterly surface winds will coincide with 10-20 percent RH through the mid to late afternoon hours. While Critical meteorological conditions will most likely develop across southwestern into central New Mexico, forecast ERCs are expected to reach the 60th-70th percentiles, suggesting that fuels may not be quite dry enough to support a widespread, robust wildfire-spread threat. Fuels are drier near the Trans Pecos, where forecast ERCs may reach the 80th-90th percentiles. However, westerly surface winds may sustain only in the 15-20 mph range, which is below Critical criteria. Nonetheless, the modest fuel receptiveness and dry/windy conditions should foster high-end Elevated conditions through the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Mar 10, 2022 1300 UTC Day 1 Convective Outlook

3 years 4 months ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0641 AM CST Thu Mar 10 2022 Valid 101300Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL AND NORTHERN FLORIDA... ...SUMMARY... Isolated damaging thunderstorm winds are possible over parts of central and northern Florida. ...Synopsis... Broadly cyclonic mid/upper-level flow, around a substantial longwave trough, will cover much of the CONUS through the period. An extensive fetch of west-southwest to southwest flow aloft will cover the Southeast -- ahead of a strengthening, positively tilted shortwave trough digging southeastward over the Great Basin, Four Corners and parts of AZ/NM. In that flow belt, a leading, low- amplitude shortwave trough -- evident in moisture-channel imagery over MS -- will weaken and eject northeastward to near the Delmarva Peninsula by 00Z, then out to the Atlantic thereafter. Surface analysis at 11Z showed a quasistationary, synoptic frontal zone over southern portions of SC/GA, southwestward across the AAF area and the north-central Gulf. This front will drift erratically on the mesoscale but exhibit no substantial motion through the period, bring beneath nearly parallel flow aloft. To its south, an outflow boundary was drawn across the FL Peninsula near a DAB-LEE- PIE line, also quasistationary. This boundary generally should move/redevelop erratically northward today and tonight, once the associated swath of convection and precip along and just to its north weakens and moves eastward to the Atlantic. A more-distant synoptic cold front was drawn from southern ON to southern portions of IL/MO, northern/western OK, through a weak frontal wave over northwest TX, to southeastern and north-central NM. This boundary will sag slowly southward through the period, reaching the lower Ohio Valley, central AR, the Edwards Plateau, and far west TX by 12Z tomorrow. ...FL... Widely scattered to scattered thunderstorms should both move eastward off the Gulf, and develop over the peninsula, during the day. This will occur as the inland boundary layer destabilizes today along and south of the outflow boundary. Organized multicells in bands and clusters, and perhaps isolated/transient supercells, are possible. Isolated damaging gusts will be the main concern, and large hail may occur in the most intense cores as well, even north of the boundary along the Gulf Coast of the eastern Panhandle to the coastal bend. Tornado potential is non-zero but very conditional on localized, mesobeta- to storm-scale processes and storm/boundary interactions, given the modest ambient low-level hodographs/shear values progged. Though the leading shortwave trough will pass well poleward of the outflow boundary over FL, subtle tightening of midtropospheric height gradients related to the shortwave trough, and associated low/middle-level mass response, should extend far enough south to influence organized convective potential today. Effective-shear magnitudes around 40-45 kt should be common (locally/briefly higher). Where sufficient diurnal surface heating can occur into the afternoon, behind morning clouds/precip, surface dew points from the upper 60s to low 70s F may support MLCAPE in the 1500-2000 J/kg range. During the evening, boundary-layer stabilization and decreasing deep-layer flow both are expected, resulting in reduced convective coverage and dwindling of severe potential over the bulk of the peninsula. A separate round of thunderstorms -- developing tonight over the north-central/northeastern Gulf and predominantly affecting the inland parts of the region on day 2 -- may reach coastal portions of the central/eastern FL Panhandle during the last few hours of the period (i.e., 09-12Z). At this time, forecast low-level thermodynamic profiles appear too stable for surface-based convection before 12Z, and unconditional severe wind and tornado potential appears too minimal to stretch those outlook lines westward toward the AAF area. ..Edwards/Mosier.. 03/10/2022 Read more

SPC Mar 9, 2022 2000 UTC Day 1 Convective Outlook

3 years 4 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Wed Mar 09 2022 Valid 092000Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH EARLY EVENING ACROSS NORTHERN FLORIDA INTO EASTERN SOUTH CAROLINA... ...SUMMARY... A few damaging wind gusts and isolated hail are possible through early evening from north Florida into eastern South Carolina. ...20z Update -- FL/GA/Carolinas... Convection has been struggling to initiate along the slowly south/southeastward sagging surface front this afternoon. This is likely due to early morning convection across parts of GA/FL, widespread cloudiness, and poor frontal convergence in the absence of stronger large-scale ascent. The Marginal and Slight risk areas have been trimmed based on latest surface observations, frontal position, and latest model guidance trends. The 5 percent tornado probability has been removed as veered low-level flow has become less favorable for rotation in any more robust cells that may develop. Nevertheless, MLCAPE around 500-1000 J/kg amid effective shear magnitudes of 35+ kt will conditionally support a few strong to severe storms, mainly capable of locally damaging gusts, over the next 2-4 hours. Additional convection is expected to redevelop across parts of the FL Panhandle into southern GA and the Carolinas overnight in a continued warm advection regime. However, this activity is expected to be elevated and pose little severe risk. Some Marginal risk for damaging gusts may persist across parts of north FL overnight into early Thursday morning closer to the effective frontal boundary. ..Leitman.. 03/09/2022 .PREV DISCUSSION... /ISSUED 1011 AM CST Wed Mar 09 2022/ ...FL/GA/SC... Two ongoing clusters of thunderstorms will likely persist through the day, posing a risk of damaging winds or a couple of tornadoes. One cluster is currently over the Big Bend region of FL, and will track across north FL this afternoon. One persistent supercell embedded within this cluster has shown occasional tornado potential. The air mass ahead of the storms is moist and moderately unstable, and convection is likely to continue eastward and offshore through the day. Low level winds will slowly weaken and veer in this area, so the extent of severe risk is uncertain. Nevertheless, given the mesoscale organization of the cluster and sufficient parameter space, will maintain the SLGT risk for this region. The second cluster of storms is over east-central GA along the primary surface boundary. These storms have weakened somewhat during the past couple of hours, but will be moving through a moist and unstable air mass over eastern SC this afternoon. Most model solutions indicate that this activity re-intensifies, with a potential for locally damaging wind gusts and perhaps a tornado or two. Thunderstorms are also expected to re-develop late tonight over parts of southern AL/GA and the FL panhandle. However, these storms should be elevated above a relatively stable surface layer. Therefore it appears the risk of severe storms is quite limited. Read more

SPC Day 2 Fire Weather Outlook

3 years 4 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0141 PM CST Wed Mar 09 2022 Valid 101200Z - 111200Z No changes. See previous discussion below. ..Bentley.. 03/09/2022 .PREV DISCUSSION... /ISSUED 0157 AM CST Wed Mar 09 2022/ ...Synopsis... Another in a series of mid-level impulses embedded in the larger scale cyclonic upper flow regime will traverse the Southwest tomorrow/Thursday, supporting surface low development across central New Mexico. Dry and windy surface conditions will result, with 15-25 mph sustained westerly surface winds overlapping 15-20 percent RH during the mid to late afternoon hours, mainly across southern New Mexico into the Trans Pecos region of southwest Texas. Elevated highlights have been introduced to address the wildfire-spread threat. Concerns for mid-level cloud cover exist over the Elevated area, and forecast ERCs are expected to be in the 60-70 percent range where the best surface wind/RH overlap will occur, precluding the introduction of Critical highlights this outlook. Critical highlights may be introduced in future outlooks if concerns with cloud cover are resolved and guidance trends upward in surface wind speeds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook

3 years 4 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Wed Mar 09 2022 Valid 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN HIGH PLAINS... No changes. See previous discussion below. ..Bentley.. 03/09/2022 .PREV DISCUSSION... /ISSUED 0127 AM CST Wed Mar 09 2022/ ...Synopsis... Broad cyclonic flow will prevail across the south-central U.S today. During the day, a mid-level impulse embedded in the broader cyclonic upper flow will impinge on the Plains states, encouraging the development and intensification of a surface low across the southern High Plains. To the west of the low, critically dry and windy conditions will develop and support wildfire-spread potential. ...Southern High Plains... By afternoon, intensifying gradient flow from the passing surface cyclone will support 20+ mph sustained west-southwesterly surface winds coinciding with 15 percent RH from roughly 20-00Z across much of central, southern, and eastern New Mexico into the Oklahoma/Texas Panhandles, and the Trans Pecos region of southwest Texas. Low-end Critical fire weather conditions are expected given that fuels remain modestly receptive to wildfire spread (i.e. forecast ERCs in the 60-80 percent range). However, guidance has trended weaker with the surface winds, and the latest guidance consensus does indicate the potential for some high-level cloud cover across central New Mexico, which may reduce boundary-layer mixing. If guidance continues to trend weaker with the winds, the Critical area may need to be removed for the 17Z Day 1 Fire Weather Outlook update. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Mar 9, 2022 1730 UTC Day 2 Convective Outlook

3 years 4 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1056 AM CST Wed Mar 09 2022 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN AND CENTRAL FLORIDA... ...SUMMARY... Thunderstorms capable of isolated damaging winds will be possible Thursday across parts of the northern Florida peninsula. ...Synopsis... A broad upper trough will envelop much of the CONUS on Thursday. A shortwave embedded within larger-scale flow will dig across the Southwest while a second shortwave traverses the northern Plains and Upper Midwest. This will maintain moderate southwesterly deep layer flow across much of the southern and eastern U.S. A surface front will extend from the western Gulf of Mexico toward the FL/GA border. The front is not expected to move much during the day across GA/FL, but convective outflows from ongoing and redeveloping diurnal convection will push the effective boundary southward across northern FL. ...Northern/Central FL... Elevated convection is expected at the beginning of the period along and to the north of the surface front. This activity will initially be maintained by a modest southwesterly low-level jet and moderate instability during the morning. Outflow from morning storms will propagate southward, acting as the effective surface front, and becoming a focus for additional thunderstorm development through the afternoon hours. While lapse rates are forecast to remain poor, moderate vertical shear (effective shear magnitudes around 35-45 kt) and MLCAPE values around 1000-1500 J/kg should maintain at least transient organized convection. Low-level shear is expected to weaken through the day, with hodographs becoming less favorable for low-level rotation, while deep-layer boundary-parallel flow will mainly support clusters/bowing segments. The main hazard with convection through late afternoon will be strong to locally damaging wind gusts. ..Leitman.. 03/09/2022 Read more

SPC Mar 9, 2022 1630 UTC Day 1 Convective Outlook

3 years 4 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1011 AM CST Wed Mar 09 2022 Valid 091630Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING FROM NORTH FLORIDA INTO EASTERN SOUTH CAROLINA... ...SUMMARY... Damaging wind gusts, a couple of tornadoes, and isolated hail are possible today from north Florida into eastern South Carolina. ...FL/GA/SC... Two ongoing clusters of thunderstorms will likely persist through the day, posing a risk of damaging winds or a couple of tornadoes. One cluster is currently over the Big Bend region of FL, and will track across north FL this afternoon. One persistent supercell embedded within this cluster has shown occasional tornado potential. The air mass ahead of the storms is moist and moderately unstable, and convection is likely to continue eastward and offshore through the day. Low level winds will slowly weaken and veer in this area, so the extent of severe risk is uncertain. Nevertheless, given the mesoscale organization of the cluster and sufficient parameter space, will maintain the SLGT risk for this region. The second cluster of storms is over east-central GA along the primary surface boundary. These storms have weakened somewhat during the past couple of hours, but will be moving through a moist and unstable air mass over eastern SC this afternoon. Most model solutions indicate that this activity re-intensifies, with a potential for locally damaging wind gusts and perhaps a tornado or two. Thunderstorms are also expected to re-develop late tonight over parts of southern AL/GA and the FL panhandle. However, these storms should be elevated above a relatively stable surface layer. Therefore it appears the risk of severe storms is quite limited. ..Hart/Lyons.. 03/09/2022 Read more

SPC Mar 8, 2022 1300 UTC Day 1 Convective Outlook

3 years 4 months ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0651 AM CST Tue Mar 08 2022 Valid 081300Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT OVER PARTS OF THE CENTRAL GULF COAST... ...SUMMARY... A marginal risk for severe thunderstorms exists tonight over parts of the central Gulf Coast. ...Synopsis... A series of mid/upper-level shortwave troughs, digging southward from western Canada, will reinforce the mean western CONUS trough, despite the ejection of an initially strong basal shortwave now over southern CO, NM and northwestern Chihuahua. The latter perturbation will deamplify somewhat, yet remain a well-defined shortwave trough, as it reaches parts of western KS, western OK, and northwest TX around 00Z. By 12Z, the trough should weaken further, with its 500-mb vorticity center reaching southern IL. A more-subtle, southern-stream perturbation -- initially apparent in moisture-channel imagery over the middle TX coast and vicinity -- should eject northeastward to the northern MS/northwestern AL region today, with some convective vorticity supplementation possible. This feature should accelerate northeastward near or offshore from the Mid-Atlantic Coast by the end of the period. At the surface, a cold front was drawn on the 11Z chart from offshore of New England southwestward across the SC coastal plain, becoming quasistationary southwestward across southwestern GA, across Choctawhatchee Bay and the mouth of the Mississippi River, and the northwestern Gulf. A weak frontal-wave low should develop over the southeastern LA/southeastern MS area this evening and ripple northeastward/inland along the front toward the GA/NC/TN border region by 12Z. Slight warm-frontal/northwestward motion should occur to its northeast, and cold-frontal advance to its southwest. A separate cold front, related to northern-stream upper-air processes, was analyzed across eastern ND, western SD, northeastern WY, and western MT. This boundary should move to parts of the upper Great Lakes, central Plains and central Rockies through the period, remaining well north of the first frontal zone. ..Central Gulf Coast... Isolated thunderstorms are possible throughout today and this evening along/ahead of the front -- with greater convective coverage in the zone of strongest large-scale lift (related to the ejecting TX Gulf Coast perturbation) behind the boundary. All this activity should remain non-severe, amidst little or no surface-based instability and moisture/buoyancy too weak for a substantial large-hail concern. However, late tonight after 06Z, a combination of strengthening warm-sector moisture and low-level lift near the low will support the potential for widely scattered thunderstorms moving northeastward over and just east of the frontal zone, offering isolated damaging gusts and a marginal tornado threat. The late-night activity also will be supported by large-scale lift in the form of strengthening low-level warm advection, collocated with a plume of moist advection and transport in a broadening LLJ. Surface dew points in the mid/upper 60s F will spread inland somewhat, with values near 70 F possible along the immediate coast and offshore. Though lapse rates in about the lowest 1/2 km and perhaps a few other layers beneath the 700 mb level near-surface lapse rates will remain weak, forecast soundings suggest MLCAPE near 1000 J/kg is possible over the Mississippi River mouth and from around MOB/PNS southward, and 500 J/kg across the rest of the outlook area. Though the LLJ core/speed max should remain north of the front, the nocturnal LLJ broadening across the boundary and into the warm sector will also result in enlarging low-level shear/hodographs, supporting effective SRH in the 150-250 J/kg range. Meanwhile, tightening of gradient flow aloft, related to the passage of both aforementioned shortwave troughs to the north, should help effective-shear magnitudes to strengthen to the 40-50-kt range. Minor eastward expansion of the outlook area is to give more room for potential movement of prefrontal convection over the western FL Panhandle by 12Z tomorrow. ..Edwards/Mosier.. 03/08/2022 Read more

SPC Mar 7, 2022 1300 UTC Day 1 Convective Outlook

3 years 4 months ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Mon Mar 07 2022 Valid 071300Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE VALLEY/APPALACHIANS TO MID-ATLANTIC STATES... ...SUMMARY... Locally damaging wind gusts may accompany isolated thunderstorms from the Tennessee Valley and Appalachians to the coastal Mid-Atlantic today into this evening. ...Tennessee Valley/Appalachians to Mid-Atlantic coast... A lead shortwave trough/related jet streak, which are embedded within phasing westerlies, will quick spread northeastward from the Midwest to the Northeast and New England by tonight, while a secondary southern-stream trough evolves the southern Rockies. This will result in neutral height tendencies/limited overall forcing for ascent, as well as some mid-level warming, where moisture is more readily available across the Southeast States/southern Appalachians ahead of a cold front. Early this morning, a nearly continuous northeast/southwest-oriented line of thunderstorms extends from central Kentucky to Middle Tennessee and northern Mississippi. There has been a general updraft/downdraft intensity decrease in the predawn hours, but the organization of the line has nonetheless been maintained in the presence of weak buoyancy and very strong low-level/deep-layer shear. On the southern end, across the Tennessee Valley and southern Appalachians vicinity, low-level convergence may tend to weaken today, and while considerable cloud cover exists ahead of the cold front/convective line, a semi-moist air mass persists (60s F surface dewpoints) and a modest intensity boost could occur into this afternoon as the boundary layer warms. This may result in the potential maintenance of a semi-broken squall line and other bands of storms. Isolated damaging winds are the primary hazard. Farther north, across the central/northern Appalachians vicinity to the coastal Mid-Atlantic, a modest intensity/organizational uptick may occur near the cold front this afternoon as the cyclone continues to deepen from the Ohio Valley toward the Northeast/New England. Surface dewpoints will be limited to the 50s F, but a plume to relatively steep mid-level lapse rates may contribute to weak near-surface-rooted buoyancy, potentially with areas of a coupled hundred J/kg SBCAPE. This may be sufficient for an increasing potential for convectively augmented wind gusts, even in the relative absence of lightning, across the Appalachians this afternoon, and east of the mountains and toward the coastal Mid-Atlantic by early evening. Localized wind damage may occur. ..Guyer/Mosier.. 03/07/2022 Read more

SPC Mar 4, 2022 1300 UTC Day 1 Convective Outlook

3 years 4 months ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0659 AM CST Fri Mar 04 2022 Valid 041300Z - 051200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible today across portions of the southwestern U.S. into Colorado. Isolated thunderstorms are also expected late tonight from Nebraska into Iowa and southern Minnesota. ...Southwest States/Four Corners... A lead shortwave trough and related speed max over southern California this morning will eject northeastward and reach the Four Corners area this evening and the central High Plains late tonight. Along and north of this jet, cooling mid-level temperatures and steep lapse rates will contribute to weak buoyancy. This likely will be adequate for isolated semi-dry, high-based convection. While convection may struggle to produce appreciable precipitation, gusty winds could accompany some of this convection, especially during the afternoon across east/southeast Utah into western Colorado. While some stronger thunderstorm-related winds could materialize, the potential for severe-caliber thunderstorm-related gusts is currently expected to remain low. ...Central Plains/Upper Midwest... Late tonight, in tandem with weak height falls, an increasingly strong south-southwesterly low-level jet will develop across the central/southern Plains toward the upper Mississippi Valley. Elevated moisture transport will contribute to thermodynamic profiles that are increasingly conducive for thunderstorms, particularly across eastern Nebraska into Iowa and southern Minnesota (mainly 10 pm CST onward). While a few stronger thunderstorm updraft cores with hail may materialize late tonight, current expectations are for hail magnitudes to remain below severe levels given modest elevated buoyancy and an expected flow weakness in the lower part (650-800mb) of the cloud-bearing layer. ..Guyer/Dean.. 03/04/2022 Read more
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