SPC Aug 8, 2022 1730 UTC Day 2 Convective Outlook

2 years 11 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Mon Aug 08 2022 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON ACROSS PARTS OF CENTRAL OREGON AND PARTS OF THE NORTHERN MID ATLANTIC INTO SOUTHERN NEW ENGLAND... ...SUMMARY... Isolated to widely scattered strong thunderstorms may impact parts of central Oregon, as well as portions of the Mid Atlantic and southern New England, Tuesday afternoon, and pose at least some risk for severe weather. ...Synopsis... In the southern mid- and subtropical latitudes, models indicate that weak lower/mid tropospheric ridging will prevail across the western Atlantic into much of the Southeast through this period. At the same time, to the west, a mid-level high is forecast to become increasingly prominent near/east of the Rockies into much of the Great Plains, downstream of amplified mid-level troughing near/offshore of the U.S. Pacific coast. While there will likely be little, if any, eastward progression of this larger-scale troughing, a fairly deep embedded mid-level low may migrate slowly north-northeastward offshore of the northern California/southern Oregon coast. Flow in the higher latitudes likely will remain more zonal and progressive. This is forecast to include one significant mid-level trough, with a couple of vigorous embedded smaller-scale perturbations, shifting east of the Canadian Prairies through the northern Ontario/Hudson Bay/western Quebec vicinity by 12Z Wednesday. A much more modest preceding perturbation is forecast to accelerate across and east of the Canadian Maritimes and New England into the northern Atlantic. This will be accompanied by the southward advancement of one surface cold front across the St. Lawrence Valley, and to the lee of the lower Great Lakes, offshore of New England into northern Mid Atlantic coast by late Tuesday night. The western flank of this front likely will stall across the lower Ohio into middle Mississippi Valleys, while a reinforcing front advances into the Upper Midwest and northern Great Plains. Moisture content will remain seasonably high along and to the south of the lead front, to the east of the Rockies, while monsoonal moisture will gradually advect around the southwestern periphery of the strengthening high, from the Southwest into the northern intermountain region, to the east of the developing low offshore of the Pacific coast. ...Northeast... Large-scale forcing for ascent along and ahead of the southward advancing front appears likely to remain generally modest to weak. However, strong heating of a moist boundary layer (temps rising into the 90s with surface dew points in the mid 60s to around 70F) may contribute to moderate CAPE (on the order of 1000-2000 J/kg) along the front and pre-frontal surface trough, inland of the northern Mid Atlantic into southern New England coast by Tuesday afternoon. It appears that this will be sufficient to support widely scattered to scattered thunderstorms. Although deep-layer shear will be weak, model forecast soundings indicate southwesterly to westerly flow around 20 kt in the 850-700 mb layer. This may be enough, coupled with the fairly steep low-level lapse rates and potential heavy precipitation loading, to support the risk for a few potentially damaging wind gusts before storms weaken by Tuesday evening. ...Central Oregon (near/east of the Cascades)... Downstream (to the northeast of the approaching mid-level low), forcing for ascent is generally forecast to contribute to considerable thunderstorm development Tuesday afternoon into Tuesday evening. Forecast soundings indicate that CAPE may remain limited to 500-1000 J/kg or less, but beneath 30-70 kt southerly flow in the 500-300 mb layer, strong deep-layer shear will be at least conditionally supportive of isolated supercells posing a risk to produce severe hail and locally strong surface gusts. ..Kerr.. 08/08/2022 Read more

SPC MD 1666

2 years 11 months ago
MD 1666 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL/EASTERN NY...NORTHWEST CT...WESTERN MA...AND SOUTHERN VT
Mesoscale Discussion 1666 NWS Storm Prediction Center Norman OK 1158 AM CDT Mon Aug 08 2022 Areas affected...Central/eastern NY...northwest CT...western MA...and southern VT Concerning...Severe potential...Watch unlikely Valid 081658Z - 081830Z Probability of Watch Issuance...20 percent SUMMARY...Isolated strong/damaging gusts with downbursts will be possible this afternoon, but the threat appears to be too marginal for a watch. DISCUSSION...To the east of a midlevel perturbation and thicker clouds over western NY, surface temperatures are warming into the upper 80s/near 90 F, with boundary-layer dewpoints holding in the lower 70s from central NY eastward. Despite poor midlevel lapse rates, MLCAPE has increased to 1000-1500 J/kg, with minimal convective inhibition. Weak ascent in advance of the subtle midlevel trough and continued surface heating/mixing will support widely scattered thunderstorm development through the afternoon. Vertical shear is weak in the warm sector, but 20-30 kt westerly flow in the 700-500 mb layer will support cells/multicell clusters that will spread eastward. Precipitation loading in the stronger updrafts, in combination with steepening low-level lapse rates and DCAPE near 1000 J/kg, will support the threat for a few strong downbursts capable of producing isolated wind damage. ..Thompson/Hart.. 08/08/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF... LAT...LON 42047527 42267571 42727588 43087590 43487566 43807536 43967460 44067354 44087299 44047285 43497242 42877250 42257271 41827315 41607383 41957463 42047527 Read more

SPC Aug 8, 2022 1630 UTC Day 1 Convective Outlook

2 years 11 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1052 AM CDT Mon Aug 08 2022 Valid 081630Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF SOUTHERN LOWER MICHIGAN AND NORTHERN INDIANA INTO WESTERN NEW ENGLAND.... ...SUMMARY... Isolated damaging thunderstorm gusts may occur today from parts of southern Lower Michigan and northern Indiana into western New England. ...MI/IN/OH... Morning water vapor loop shows a shortwave trough moving across Lake Superior into Ontario. The associated trailing cold front extends across northern Lower MI into northern IL. Considerable cloud cover is present ahead of the front, but a combination of dewpoints in the 70s and broken sunshine will yield afternoon MLCAPE values of 1500-2000 J/kg. Most 12z model solutions suggest that scattered thunderstorms will develop later today as the cold front sags into southern Lower MI and northern IN/OH. Mid level lapse rates are weak, but steep low-level lapse rates and sufficient steering flow will pose some risk of locally gusty/damaging winds in the strongest cells. ...NY/western New England... Visible satellite imagery showed mostly clear skies this morning from central NY into much of central/southern New England. This area has already begun to show a considerable cu field, and is likely to develop into isolated thunderstorms by mid-afternoon. Temperatures in the mid/upper 80s will lead to steep low-level lapse rates and MLCAPE values around 1500 J/kg. Flow aloft is rather weak, but the strongest cells in this area may produce gusty/damaging winds this afternoon and early evening. ..Hart/Thompson.. 08/08/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 11 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CDT Mon Aug 08 2022 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL TO SOUTH-CENTRAL OREGON... The previous forecast remains on track with only minor adjustments needed. Isolated showers/thunderstorms are already ongoing this morning, but will become more numerous by mid/late afternoon. An increase in mid-level moisture was sampled in regional 12 UTC soundings with dry boundary-layer conditions noted along/east of the Cascades. These observed trends and latest ensemble guidance both support the ongoing forecast. See the previous discussion below for additional details. ..Moore.. 08/08/2022 .PREV DISCUSSION... /ISSUED 0137 AM CDT Mon Aug 08 2022/ ...Synopsis... Upper ridging will dominate the Interior West as an upper low meanders off of the West Coast today. Monsoonal moisture will pivot northwestward around the periphery of the upper ridge across the Desert Southwest into the Pacific Northwest, where scattered thunderstorms are expected to develop by afternoon. Across far southern Washington into central Oregon and extreme northern California/northwestern Nevada, many of the thunderstorms are expected to be high-based. Forecast soundings in this area by afternoon peak heating suggest that a very dry boundary layer will extend up to 500 mb amid precipitable water values around 0.75 inches. As such, a mix of wet and dry thunderstorms is expected to overspread modestly to highly receptive fuels, warranting isolated dry thunderstorm highlights. Scattered dry thunderstorm highlights were also maintained across central/southern Oregon, where the latest high-resolution guidance consensus continues to depict the greatest concentration of thunderstorms. Lastly, high-resolution ensemble guidance shows relatively high potential for erratic and gusty winds (perhaps 30-45 kts) accompanying the stronger thunderstorms across the southern Cascades, which may exacerbate any new or pre-existing fire starts. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Aug 7, 2022 1730 UTC Day 2 Convective Outlook

2 years 11 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sun Aug 07 2022 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The severe thunderstorm threat is expected to be relatively low on Monday. ...Lower MI into parts of the Midwest... A midlevel shortwave trough will move quickly from the upper Great Lakes toward parts of Ontario and Quebec on Monday, as a trailing cold front moves through parts of the Midwest and eventually the lower Great Lakes. Depending on the extent of diurnal heating that can occur in the wake of morning convection, moderate buoyancy may develop by afternoon within a very moist environment. Deep-layer will be modest at best across lower MI, and even weaker farther south, but a belt of somewhat enhanced flow (25-35 kt) in the 850-700 mb layer may support storm clusters capable of isolated wind damage, if sufficient heating and steepening of low-level lapse rates can occur. Wind probabilities may eventually be needed for portions of this region, depending on how much recovery/heating can occur in the wake of morning cloudiness and convection. ...Arizona... A few strong storms will again be possible across parts of Arizona, mainly across southeast AZ and also potentially along the Mogollon Rim, as moderate buoyancy develops within a seasonably moist environment. Depending on the extent of recovery that can occur in the wake of convection on D1/Sunday, a threat of isolated severe gusts and perhaps some hail may evolve, though confidence is too low to add probabilities at this time. ..Dean.. 08/07/2022 Read more

SPC Aug 7, 2022 1630 UTC Day 1 Convective Outlook

2 years 11 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1119 AM CDT Sun Aug 07 2022 Valid 071630Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF ARIZONA...THE CENTRAL HIGH PLAINS...IOWA...AND NORTHERN MAINE.... CORRECTED FOR GRAPHICAL CREATION ERRORS ...SUMMARY... Isolated severe thunderstorm gusts are possible across parts of Arizona, the Upper Midwest and central High Plains, and northern Maine this afternoon and evening. ...CO/KS... Morning surface analysis shows a persistent boundary extending across northwest KS into southeast CO. Dewpoints are in the 60s along and north of the boundary across much of eastern CO, and it appears that considerable daytime heating will occur over parts of the area. This will result in afternoon MLCAPE values of around 1000 J/kg over much of eastern CO, with values up to 2500 J/kg over western KS. Most 12z models agree that convection will form over the foothills of central CO by mid afternoon and spread eastward through early evening. Winds aloft are sufficiently strong to help propagate the convection off the higher terrain, as well as organize a few of the updrafts. Locally damaging wind gusts will be the main threat, but a few storms in/near the foothills may produce hail. Farther east in the plains, strong CAPE values and convergence along the boundary may be sufficient for a landspout or two, along with gusty/damaging winds. ...IA... Widespread overnight convection has left an outflow boundary extending across central IA. It is unclear how much daytime heating will occur in this area due to remnant clouds. However, the potential will exist for isolated gusty/damaging wind gusts in the stronger cells this afternoon and evening if sufficient low-level lapse rates can develop. ...Northern ME... A surface cold front is sagging southward across Quebec towards northern ME. A moist and marginally unstable air mass will be present this afternoon as storms initiate along the front. Forecast soundings suggest sufficient deep-layer shear for an isolated rotating storm or two, capable of damaging wind gusts or hail. ...AZ... Strong heating is occurring today over most areas of central/southern AZ. Clusters of thunderstorms are expected to develop by mid-afternoon over the mountains of central/eastern AZ and propagate southwestward. The mesoscale details of convective coverage are unclear, but there will be potential for damaging wind gusts if storms can persist as they track into south-central AZ this evening. ..Hart/Weinman.. 08/07/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 11 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1057 AM CDT Sun Aug 07 2022 Valid 071700Z - 081200Z The forecast remains on track with only minor adjustments required based on latest hi-res convective guidance. See the previous discussion below for details. ..Moore.. 08/07/2022 .PREV DISCUSSION... /ISSUED 1229 AM CDT Sun Aug 07 2022/ ...Synopsis... A mid-level short-wave trough positioned over the northern Plains will shift east into the Great Lakes region throughout the day. Meanwhile, an upper-level ridge will build across the northern Rockies, and a closed upper-level low will approach the northern California/southern Oregon coast. At the surface, a cold front will continue a slow progression across the northern/central High Plains. ...Isolated Dry Thunderstorms: Central/Southern Oregon/far Northern California/far Northwest Nevada... The area delineating potential for isolated dry thunderstorms has been expanded slightly toward the northwest, based on 00z CAM guidance. Coverage of this activity should remain isolated, supported by forecast PWAT values still remaining near or below 0.75-0.8 inches, and fuels across the region remain highly receptive to large-fire spread. ...Wind/RH: Northern Oregon/Southern Washington... Localized elevated conditions may develop during the afternoon, as a hot/dry airmass will be present over the region. Locally enhanced offshore flow will likely occur in terrain-favored regions of the Cascades. Given the isolated nature of the threat, however, no highlights have been introduced at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Aug 6, 2022 1730 UTC Day 2 Convective Outlook

2 years 11 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Aug 06 2022 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF SOUTHERN ARIZONA... ...SUMMARY... Thunderstorms capable of isolated severe wind gusts are possible across parts of Arizona Sunday afternoon and evening. ...Arizona... Scattered thunderstorms are expected to develop Sunday afternoon across parts of Arizona, within a relatively moist and moderately unstable environment. Initial development is expected across the higher terrain, with east-northeasterly midlevel flow favoring the potential for outflow-driven clusters to move into the lower desert regions by evening, with an attendant risk of isolated severe wind gusts. ...CO Front Range into the central High Plains... Scattered to widespread thunderstorms are expected along the CO Front Range within a post frontal regime, with more isolated development possible across adjacent portions of the central High Plains. Veering wind profiles north of the front will support effective shear of 20-30 kt within a moderately unstable environment, and a couple of semi-organized storms will be possible, though a tendency for storm mergers is expected to limit the severe threat to some extent. ...Midwest into parts of the Great Lakes... Substantial convection is expected across parts of the Midwest during the D1/Saturday period into early Sunday, which casts considerable uncertainty regarding the severe potential later in the day. There is some potential for afternoon/evening redevelopment along any remnant outflow boundaries, and also along a cold front moving across parts of IA/MN. Stronger deep-layer shear is expected to remain north/west of the greater surface-based instability, but a few stronger cells/clusters will be possible across some portion of this area, and severe probabilities may eventually be needed, depending on shorter-term observational and guidance trends. ...Northern New England... Northern New England will be along the southern fringe of stronger midlevel flow on Sunday. While the environment is expected to remain relatively moist, very weak midlevel lapse rates will tend to limit buoyancy and thunderstorm coverage for much of the day. There is some chance for isolated storms to develop across the higher terrain (if sufficient heating can occur), and/or spread south of the international border by early evening. Should this occur, some locally damaging wind threat may result, though confidence remains too low for wind probabilities at this time. ..Dean.. 08/06/2022 Read more

SPC Aug 6, 2022 1630 UTC Day 1 Convective Outlook

2 years 11 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CDT Sat Aug 06 2022 Valid 061630Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE UPPER MISSISSIPPI VALLEY... ...SUMMARY... A few severe thunderstorms may develop this afternoon and evening from the upper Mississippi Valley into the central High Plains. ...IA/MN/WI... Morning satellite imagery shows a canopy of cloud cover associated with a decaying MCS over MN/WI. The southern edge of clouds extends from northwest IA into far southern MN and southwest WI. Strong heating and ample low-level moisture will be present today to the south of this axis, with MLCAPE values expected to exceed 3000 J/kg with 20-30 knots of deep-layer mean flow. Most CAM solutions show scattered thunderstorms developing in this area by late afternoon, with a few supercell and organized multicell structures possible. Mid-level temperatures are quite warm and lapse rates are weak, suggesting that the hail risk will be limited. However, high PW values and steep low-level lapse rates will promote damaging wind gusts in the stronger cells. Therefore have added a small SLGT risk area to parts of the region. ...High Plains... Scattered high-based thunderstorms are expected to develop this afternoon and evening over the plains of eastern CO/WY and drift eastward. Forecast soundings show that winds aloft are rather strong over WY, but thermodynamics will be somewhat marginal. Isolated supercells will be possible with a risk of hail and damaging wind gusts, but the forecast coverage of intense storms appears to be in line with a MRGL category at this time. This will be re-evaluated at 20z. ..Hart/Weinman.. 08/06/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 11 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Sat Aug 06 2022 Valid 061700Z - 071200Z The previous forecast remains on track with only minor adjustments made based on trends in latest guidance. Morning water-vapor imagery reveals mid-level confluence zone along the CA/OR border that will provide weak ascent today. The 12 UTC MFR sounding sampled favorable buoyancy atop a somewhat dry boundary layer that should support a wet/dry mix of thunderstorms this afternoon. ...Willamette Valley... Dry conditions are expected this afternoon through the Willamette Valley with RH values falling as low as 20%. Terrain-augmented winds may reach near 15 mph and support areas of elevated conditions. While noted, this potential remains too localized for a broader risk area. ..Moore.. 08/06/2022 .PREV DISCUSSION... /ISSUED 1230 AM CDT Sat Aug 06 2022/ ...Synopsis... A mid-level short-wave trough will move across portions of the northern CONUS, from the Pacific Northwest to the northern Plains. Meanwhile, an upper-level ridge will remain quasi-stationary over the central CONUS with weak mid- to upper-level flow prevailing in most areas. At the surface, a cold front will enter portions of the northern/central High Plains. Ahead of this front, breezy southwesterly surface winds near 20 mph should develop during the afternoon across most of western Kansas and vicinity. However, RH values should generally remain above critical/elevated thresholds amid fuels that appear generally non-receptive to large-fire spread. ...Southern Oregon... An area delineating the potential for isolated dry thunderstorms has been introduced for the region. A narrow zone of convection should develop during the late afternoon hours amid dry/receptive fuels and PWAT values remaining below 0.75 inches. The highlighted area has been confined to portions of the region that received little appreciable rainfall yesterday. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Aug 5, 2022 1730 UTC Day 2 Convective Outlook

2 years 11 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1210 PM CDT Fri Aug 05 2022 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... A few strong to severe storms may affects parts of the central Plains and upper Mississippi Valley Saturday afternoon and evening. ...Synopsis... Upper ridging is forecast to be centered over the central Plains early Saturday morning, covering much of the Southwest, central/southern Plains, and MS Valley. This ridging is expected to remain largely in place throughout the day, with some modest dampening throughout its far northern periphery as a shortwave trough moves from Pacific Northwest into the northern High Plains. This shortwave trough will follow in the wake of another shortwave moving across the Hudson Bay/Ontario. This train of shortwave troughs will help maintain broad upper troughing over the Canadian Prairie Provinces and far northern High Plains/northern Plains, with modestly enhanced flow aloft extending through the base of this troughing from WY through the Upper Midwest/Upper Great Lakes. Surface pattern is expected to feature a cold front stretching from the MN arrowhead vicinity southwestward through central NE early Saturday morning. This front is forecast to progress gradually southward/southeastward during the day, ending the period extending from central WI southwestward into western KS. Interaction between this front and the warm and moist air mass across the central Plains and Upper MS Valley will support thunderstorm development throughout the day. ...Central Plains...Upper Midwest... Showers and thunderstorms will likely be ongoing Saturday morning to the north of the cold front mentioned in the synopsis, supported by warm-air advection across the frontal zone. Steep mid-level lapse rates will likely still be in place amid modest vertical shear, resulting in the potential for few updrafts capable of hail and/or a damaging downburst. This early morning activity should diminish as it moves northeastward, with additional thunderstorm development anticipated during the afternoon, both along the front and in its wake. Thunderstorm initiation along the front appears most probable from the north-central WI southwestward into north-central NE, where daytime heating will push temperatures in the upper 90s/low 100s amid mid to upper 60s dewpoints. Strong buoyancy will support intense updrafts, but the highest storm coverage may be displaced south of the stronger deep-layer vertical shear and high LCLs. These conditions suggests a mostly outflow-dominant storm mode, with a few damaging wind gusts are possible. Only exception is across WI and southeast MN, where vertical shear is expected to be strong enough for a few supercells. Here, isolated hail is possible in addition to damaging wind gusts. ..Mosier.. 08/05/2022 Read more

SPC MD 1654

2 years 11 months ago
MD 1654 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST AND WESTERN VA...SOUTHEAST WV...NORTHEAST TN...NORTHWEST NC
Mesoscale Discussion 1654 NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 05 2022 Areas affected...southwest and western VA...southeast WV...northeast TN...northwest NC Concerning...Severe potential...Watch unlikely Valid 051711Z - 051915Z Probability of Watch Issuance...20 percent SUMMARY...Isolated gusts 45-60 mph are possible and these gusts will likely be capable of localized pockets of wind damage. DISCUSSION...Visible-satellite imagery shows thunderstorms developing over the past hour near the ridge tops of the Appalachians. Surface conditions show temperatures warming through the upper 80s in the low elevations with dewpoints in the lower 70s. Continued heating will further steepen low-level lapse rates as temperatures warm into the 90s. NAM forecast soundings indicate 2000-3000 J/kg MLCAPE is present over southwest and western VA and surrounding states. This buoyancy magnitude appears to be adequately depicted based on midday surface observations compared to the RAP-based SPC Objective Analysis (1000-1500 J/kg MLCAPE). With PW 1.75 to 2 inches, ample water-loading potential is evident. The steepening of 0-3 km lapse rates in excess of 8 deg C/km will favor strong gust potential. A weak tropospheric wind profile will favor slow-moving, pulse-like storms. Isolated to widely scattered strong gusts 45-55 mph are probable with the stronger cores (locally up to around 60 mph) with pockets of wind damage the likely result. ..Smith/Hart.. 08/05/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LWX...RNK...PBZ...RLX...GSP...MRX... LAT...LON 36938205 37788098 39397883 39407824 39127786 38637788 37007916 35788167 35838209 36188227 36938205 Read more

SPC MD 1654

2 years 11 months ago
MD 1654 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST AND WESTERN VA...SOUTHEAST WV...NORTHEAST TN...NORTHWEST NC
Mesoscale Discussion 1654 NWS Storm Prediction Center Norman OK 1211 PM CDT Fri Aug 05 2022 Areas affected...southwest and western VA...southeast WV...northeast TN...northwest NC Concerning...Severe potential...Watch unlikely Valid 051711Z - 051915Z Probability of Watch Issuance...20 percent SUMMARY...Isolated gusts 45-60 mph are possible and these gusts will likely be capable of localized pockets of wind damage. DISCUSSION...Visible-satellite imagery shows thunderstorms developing over the past hour near the ridge tops of the Appalachians. Surface conditions show temperatures warming through the upper 80s in the low elevations with dewpoints in the lower 70s. Continued heating will further steepen low-level lapse rates as temperatures warm into the 90s. NAM forecast soundings indicate 2000-3000 J/kg MLCAPE is present over southwest and western VA and surrounding states. This buoyancy magnitude appears to be adequately depicted based on midday surface observations compared to the RAP-based SPC Objective Analysis (1000-1500 J/kg MLCAPE). With PW 1.75 to 2 inches, ample water-loading potential is evident. The steepening of 0-3 km lapse rates in excess of 8 deg C/km will favor strong gust potential. A weak tropospheric wind profile will favor slow-moving, pulse-like storms. Isolated to widely scattered strong gusts 45-55 mph are probable with the stronger cores (locally up to around 60 mph) with pockets of wind damage the likely result. ..Smith/Hart.. 08/05/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LWX...RNK...PBZ...RLX...GSP...MRX... LAT...LON 36938205 37788098 39397883 39407824 39127786 38637788 37007916 35788167 35838209 36188227 36938205 Read more

SPC Aug 5, 2022 1630 UTC Day 1 Convective Outlook

2 years 11 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CDT Fri Aug 05 2022 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER PARTS OF THE EASTERN DAKOTAS AND NORTHWEST MINNESOTA.... ...SUMMARY... Severe thunderstorms capable of damaging wind gusts and hail are expected today across parts of the Dakotas into Minnesota. Other more isolated thunderstorm wind gusts will occur from the central Appalachians into the Mid Atlantic region. ...Northern Plains... Morning surface analysis shows a weak cold front extending across the western Dakotas. This boundary will move eastward today and provide the focus for afternoon thunderstorm development. Strong heating, dewpoints near 70F, and steep mid-level lapse rates will yield MLCAPE values 2000-3000 J/kg. CAM solutions suggest storms will form by late afternoon and early evening from central SD into northwest MN. Deep-layer shear is sufficient for organized/supercell storms capable of severe wind gusts and hail through the evening. ...Mid Atlantic to Central Appalachians... Visible satellite imagery shows mostly clear skies from east TN into much of VA, where dewpoints in the 70s will result in afternoon MLCAPE values around 2000 J/kg. Mid level lapse rates are weak, and forecast soundings show weak winds aloft through column. Nevertheless, pulse and occasional multicell storm clusters will pose a risk of gusty and locally damaging wind gusts for a few hours this afternoon. ..Hart/Smith.. 08/05/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 11 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1056 AM CDT Fri Aug 05 2022 Valid 051700Z - 061200Z An isolated dry thunderstorm risk area is introduced to portions of northern CA into southern OR. Latest MRMS rainfall estimates suggest ongoing convection is a mix of wet/dry thunderstorms with pockets of wetting rainfall. Thunderstorm chances will persist into the afternoon as a weak mid-level disturbance moves into the northern Great Basin. Forecast soundings show inverted-V soundings with cloud bases near 2.5-3 km and PWAT values near 0.8 to 1.0 inch. These thermodynamic conditions are supportive of a mix of wet/dry thunderstorms over a region with receptive fuels and a history of recent fire starts. See the previous discussion below for additional forecast concerns. ..Moore.. 08/05/2022 .PREV DISCUSSION... /ISSUED 0157 AM CDT Fri Aug 05 2022/ ...Synopsis... An upper-level shortwave trough evident on water vapor imagery this morning over the Pacific Northwest is forecast to move eastward across southern Canada today. An associated surface low over Manitoba will deepen with a trailing surface trough/cold front draped southward into the northern Plains. While the enhanced surface pressure gradient across the region will lead to windy pre-frontal and post-frontal conditions across portions of the northern Plains, the overlap of strong winds with critical RH values appears unlikely, limiting fire weather concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
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