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MD 1959 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR MUCH OF WESTERN MONTANA AND THE CENTRAL IDAHO MOUNTAINS
Mesoscale Discussion 1959 NWS Storm Prediction Center Norman OK 0321 PM CDT Mon Aug 19 2024 Areas affected...much of western Montana and the central Idaho Mountains Concerning...Severe potential...Watch possible Valid 192021Z - 192145Z Probability of Watch Issuance...60 percent SUMMARY...High-based thunderstorms are likely this afternoon and evening with a threat for severe wind gusts. DISCUSSION...Temperatures have warmed into the mid 80s across the central Idaho mountains which has eroded inhibition and resulted in scattered thunderstorm development. RAP forecast soundings show very deep mixing (perhaps as deep as 5-6km) which will support evaporative cooling and strengthening downbursts. The downstream environment across western Montana still shows moderate inhibition (per SPC mesoanalysis) which should erode further as warming continues. As this occurs, expect strengthening of ongoing storms and additional development across western Montana. Moderate upper-level flow ahead of the Pacific Northwest upper-level trough will overspread this region late this afternoon and evening which may result in storm organization and a greater severe weather threat. A severe thunderstorm watch may be needed. ..Bentley/Hart.. 08/19/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TFX...PIH...MSO...BOI...OTX... LAT...LON 44431433 44981525 47541489 49021400 49041176 49030985 48580993 46571090 45291195 44541301 44371348 44431433 Read more

MD 1957 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR VIRGINIA AND PORTIONS OF NORTH CAROLINA
Mesoscale Discussion 1957 NWS Storm Prediction Center Norman OK 0224 PM CDT Mon Aug 19 2024 Areas affected...Virginia and portions of North Carolina Concerning...Severe potential...Watch unlikely Valid 191924Z - 192130Z Probability of Watch Issuance...20 percent SUMMARY...Scattered thunderstorm activity will have potential to produce downbursts with strong to severe gusts. DISCUSSION...Thunderstorm activity has increased in coverage across Virginia and North Carolina this afternoon as lift from a mid-level trough overspreads a cold front across the region. Breaks in morning cloud cover have allowed for sufficient daytime heating and temperatures in the mid to upper 80s, with low-level lapse rates around 8 C/km. MLCAPE around 1000-1500 J/kg is analyzed in RAP objective analysis. While deep layer shear is weak, steep lapse rates and precipitable water values above 1 inch will support potential for a few strong storms with potential for downbursts capable of strong to severe gusts. Overall, this threat will likely remain too localized for watch issuance. ..Thornton/Hart.. 08/19/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...MHX...LWX...RAH...RNK... LAT...LON 36117983 36997936 38257821 38977726 39367670 39577629 39397579 38517527 37817552 36627595 35907616 35037641 34857648 35387934 36117983 Read more

MD 1958 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR EASTERN MONTANA AND WESTERN NORTH DAKOTA.
Mesoscale Discussion 1958 NWS Storm Prediction Center Norman OK 0244 PM CDT Mon Aug 19 2024 Areas affected...Eastern Montana and western North Dakota. Concerning...Severe potential...Watch possible Valid 191944Z - 192115Z Probability of Watch Issuance...40 percent SUMMARY...Some intensification is possible as storms move northeast across eastern Montana. A watch may be needed. DISCUSSION...A slow moving cluster of storms has persisted across eastern Montana through most of the day today. Somewhat more robust convection has developed southeast of the primary cluster in the presence of greater instability (2000+ J/kg MLCAPE). SPC mesoanalysis shows inhibition has mostly eroded ahead of these storms and it should completely erode in the next 1 to 2 hours. A speed max overspread eastern Montana within the last hour (sampled 40-45 knots between 4-5km on the GGW VWP). This increase in deep layer shear may support an increase in storm intensity later this afternoon. A few thunderstorms capable of large hail and severe wind gusts are expected this evening. A severe thunderstorm watch may be needed. ..Bentley/Hart.. 08/19/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...UNR...BYZ...GGW... LAT...LON 45850479 45840523 46080584 46390631 46660628 47860617 48570558 48940453 48670312 47360266 46180324 45800421 45850479 Read more

WW 0640 Status Updates
STATUS FOR WATCH 0640 HAS NOT BEEN ISSUED YET Read more

WW 0640 Status Updates
STATUS FOR WATCH 0640 HAS NOT BEEN ISSUED YET Read more

WW 0640 Status Updates
STATUS FOR WATCH 0640 HAS NOT BEEN ISSUED YET Read more

WW 640 SEVERE TSTM ID MT 192050Z - 200400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 640 NWS Storm Prediction Center Norman OK 250 PM MDT Mon Aug 19 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Idaho Western and Central Montana * Effective this Monday afternoon and evening from 250 PM until 1000 PM MDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are forming over the mountains of northern Idaho and western Montana. These storms will intensify and organize through the afternoon and spread northeastward across the watch area. Damaging wind gusts will be possible in the strongest storms. The severe thunderstorm watch area is approximately along and 70 statute miles east and west of a line from 35 miles east southeast of Salmon ID to 35 miles northeast of Cut Bank MT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 639... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 23025. ...Hart Read more

5-Day Uncertainty Track last updated Mon, 19 Aug 2024 20:43:17 GMT


Wind Speed Probabilities last updated Mon, 19 Aug 2024 21:29:18 GMT

Issued at 200 PM PDT Mon Aug 19 2024 000 WTPZ42 KNHC 192041 TCDEP2 Tropical Storm Gilma Discussion Number 6 NWS National Hurricane Center Miami FL EP072024 200 PM PDT Mon Aug 19 2024 ASCAT data valid at 1644 UTC showed that Gilma has strengthened slightly and its wind field has grown a little. While the tropical storm is still sheared, maximum winds measured by the ASCAT were between 40 and 45 kt, which after accounting for undersampling supports an intensity around 50 kt. An average of the most recent Dvorak estimates from TAFB and SAB also yields 50 kt, so that is the intensity estimate for this advisory. The maximum extent of 34 kt winds is estimated to be around 70 n mi based on the ASCAT data, mostly to the southwest in the deep convection. Although the track forecast spread in the model guidance remains unusually high, not much change was made to the NHC forecast, except to show a slightly faster forward motion in 24-48 h. Otherwise, Gilma is still expected to slow down and turn west-northwestward within the next day as the ridge currently steering the storm is gradually eroded by a deep-layer trough off the U.S. west coast. There is still quite a bit of difference between the models in the forward speed of Gilma, so the NHC forecast closely follows the consensus throughout the forecast. Only small adjustments were made to the intensity forecast. Gilma should remain sheared for another day or so, limiting the potential for strengthening during that period. After that, the shear should decrease and Gilma should strengthen. Most models continue to indicate that Gilma will approach hurricane strength later this week. The NHC intensity forecast remains very close to the various intensity consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 15.1N 116.9W 50 KT 60 MPH 12H 20/0600Z 15.5N 118.2W 55 KT 65 MPH 24H 20/1800Z 16.2N 120.0W 55 KT 65 MPH 36H 21/0600Z 16.7N 122.0W 55 KT 65 MPH 48H 21/1800Z 17.2N 123.6W 60 KT 70 MPH 60H 22/0600Z 17.8N 124.7W 70 KT 80 MPH 72H 22/1800Z 18.3N 126.0W 75 KT 85 MPH 96H 23/1800Z 19.0N 127.5W 75 KT 85 MPH 120H 24/1800Z 20.0N 130.0W 65 KT 75 MPH $$ Forecaster D. Zelinsky

Issued at 2100 UTC MON AUG 19 2024 000 FOPZ12 KNHC 192040 PWSEP2 TROPICAL STORM GILMA WIND SPEED PROBABILITIES NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 2100 UTC MON AUG 19 2024 AT 2100Z THE CENTER OF TROPICAL STORM GILMA WAS LOCATED NEAR LATITUDE 15.1 NORTH...LONGITUDE 116.9 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 50 KTS...60 MPH...95 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 18Z MON AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 18Z MON 06Z TUE 18Z TUE 06Z WED 18Z WED 18Z THU 18Z FRI PERIODS TO TO TO TO TO TO TO 06Z TUE 18Z TUE 06Z WED 18Z WED 18Z THU 18Z FRI 18Z SAT FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 15N 120W 34 2 37(39) 2(41) 1(42) 1(43) X(43) X(43) 15N 120W 50 X 3( 3) 1( 4) X( 4) X( 4) X( 4) X( 4) 20N 120W 34 X 1( 1) 2( 3) 2( 5) 2( 7) X( 7) X( 7) 15N 125W 34 X X( X) 3( 3) 5( 8) 7(15) 3(18) X(18) 20N 125W 34 X X( X) 1( 1) 6( 7) 36(43) 9(52) 1(53) 20N 125W 50 X X( X) X( X) X( X) 9( 9) 4(13) X(13) 20N 125W 64 X X( X) X( X) X( X) 4( 4) 1( 5) X( 5) 15N 130W 34 X X( X) X( X) X( X) 2( 2) 3( 5) 1( 6) 20N 130W 34 X X( X) X( X) X( X) 5( 5) 19(24) 24(48) 20N 130W 50 X X( X) X( X) X( X) 1( 1) 4( 5) 11(16) 20N 130W 64 X X( X) X( X) X( X) X( X) 2( 2) 6( 8) 25N 130W 34 X X( X) X( X) X( X) X( X) 1( 1) 4( 5) 20N 135W 34 X X( X) X( X) X( X) X( X) X( X) 4( 4) $$ FORECASTER D. ZELINSKY

Issued at 200 PM PDT Mon Aug 19 2024 000 WTPZ32 KNHC 192040 TCPEP2 BULLETIN Tropical Storm Gilma Advisory Number 6 NWS National Hurricane Center Miami FL EP072024 200 PM PDT Mon Aug 19 2024 ...GILMA STRENGTHENS A LITTLE MORE... SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...15.1N 116.9W ABOUT 705 MI...1135 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 13 MPH...20 KM/H MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 200 PM PDT (2100 UTC), the center of Tropical Storm Gilma was located near latitude 15.1 North, longitude 116.9 West. Gilma is moving toward the west near 13 mph (20 km/h). A slower west-northwestward motion is expected to begin tonight and continue through mid-week. Maximum sustained winds are near 60 mph (95 km/h) with higher gusts. Additional slow strengthening is likely for the next day or two. Gilma is forecast to approach hurricane strength in a few days. Tropical-storm-force winds extend outward up to 80 miles (130 km) from the center. The estimated minimum central pressure is 999 mb (29.50 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 800 PM PDT. $$ Forecaster D. Zelinsky

...GILMA STRENGTHENS A LITTLE MORE... As of 2:00 PM PDT Mon Aug 19 the center of Gilma was located near 15.1, -116.9 with movement W at 13 mph. The minimum central pressure was 999 mb with maximum sustained winds of about 60 mph.

Issued at 2100 UTC MON AUG 19 2024 000 WTPZ22 KNHC 192039 TCMEP2 TROPICAL STORM GILMA FORECAST/ADVISORY NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 2100 UTC MON AUG 19 2024 TROPICAL STORM CENTER LOCATED NEAR 15.1N 116.9W AT 19/2100Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 11 KT ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT. 50 KT....... 0NE 0SE 40SW 0NW. 34 KT....... 20NE 40SE 70SW 50NW. 12 FT SEAS.. 45NE 0SE 0SW 45NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 15.1N 116.9W AT 19/2100Z AT 19/1800Z CENTER WAS LOCATED NEAR 15.0N 116.5W FORECAST VALID 20/0600Z 15.5N 118.2W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 0NE 0SE 30SW 0NW. 34 KT... 30NE 40SE 80SW 50NW. FORECAST VALID 20/1800Z 16.2N 120.0W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 30NE 30SE 30SW 0NW. 34 KT... 50NE 60SE 100SW 50NW. FORECAST VALID 21/0600Z 16.7N 122.0W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 30NE 30SE 30SW 20NW. 34 KT... 70NE 90SE 100SW 60NW. FORECAST VALID 21/1800Z 17.2N 123.6W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 30SE 30SW 30NW. 34 KT... 80NE 100SE 100SW 80NW. FORECAST VALID 22/0600Z 17.8N 124.7W MAX WIND 70 KT...GUSTS 85 KT. 50 KT... 40NE 40SE 30SW 30NW. 34 KT... 80NE 90SE 100SW 80NW. FORECAST VALID 22/1800Z 18.3N 126.0W MAX WIND 75 KT...GUSTS 90 KT. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 80NE 90SE 90SW 90NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 125 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 23/1800Z 19.0N 127.5W MAX WIND 75 KT...GUSTS 90 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT... 90NE 80SE 90SW 100NW. OUTLOOK VALID 24/1800Z 20.0N 130.0W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT...100NE 80SE 80SW 100NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.1N 116.9W NEXT ADVISORY AT 20/0300Z $$ FORECASTER D. ZELINSKY

MD 1956 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR SOUTHEAST WYOMING...PARTS OF THE NEBRASKA PANHANDLE...AND MUCH OF EASTERN COLORADO
Mesoscale Discussion 1956 NWS Storm Prediction Center Norman OK 0219 PM CDT Mon Aug 19 2024 Areas affected...southeast Wyoming...parts of the Nebraska Panhandle...and much of eastern Colorado Concerning...Severe potential...Watch likely Valid 191919Z - 192045Z Probability of Watch Issuance...80 percent SUMMARY...Scattered strong to severe thunderstorms are expected this afternoon in the central High Plains with a threat for large hail and severe wind gusts. DISCUSSION...Moderate destabilization has occurred across eastern Colorado amid moist upslope flow (mid 60s dewpoints) and temperatures in the 80s. SPC mesoanalysis has indicated inhibition is decreasing along the Front Range. At least some inhibition is expected to remain across the Plains this afternoon which will likely limit storm initiation, however, scattered thunderstorm development is expected along the higher terrain which should intensify as it moves east into the more unstable airmass across the Plains this afternoon and evening. Mid-upper level flow of 30 to 40 knots combined with easterly flow at the surface will provide ample wind shear for some storm organization including the potential for a few supercells Despite the relatively warm temperatures aloft beneath the upper-ridge axis, steep lapse rates and the moderate shear should support some hail threat, especially early in the storm lifecycle when storm mode is more discrete. Later this afternoon and especially into the evening, expect the threat to transition to severe wind gusts with one or more clusters of storms which may develop out of the afternoon/early evening convection. ..Bentley/Hart.. 08/19/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...GLD...PUB...BOU...CYS... LAT...LON 37890474 38540471 38970472 39720475 40790473 42110458 42450298 41310246 39900251 38220328 37520393 37890474 Read more

MD 1955 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NEW ENGLAND
Mesoscale Discussion 1955 NWS Storm Prediction Center Norman OK 0125 PM CDT Mon Aug 19 2024 Areas affected...portions of New England Concerning...Severe potential...Watch unlikely Valid 191825Z - 192030Z Probability of Watch Issuance...5 percent SUMMARY...Scattered thunderstorm activity may produce strong to severe gusts through the afternoon. DISCUSSION...Thunderstorm activity ongoing along and ahead of a cold front across portions of New England has shown an uptick in coverage over the last hour. Much of the region has been under mid-level cloud cover through the morning. However, a few breaks in the clouds have allowed temperatures to warm into the 80s with MLCAPE around 500-1000 J/kg. Deep layer shear for organization remains mostly offshore, with poor low to mid-level lapse rates. A few clusters of stronger storms may produce strong to severe gusts at times. Overall, the lack of support for organization of a more widespread severe threat will keep this threat localized precluding the need to for a watch. ..Thornton/Hart.. 08/19/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP... LWX... LAT...LON 39177503 39167532 39297597 39877626 40557581 43067419 43987278 43997120 43827082 43107066 42647086 41797190 39317479 39177503 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 19 2024 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS...AND OVER WESTERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are possible across portions of the northern and central High Plains, and over western Montana into tonight. Large hail and severe gusts are the primary hazards. ...20Z Update... Within the Slight Risk area over the central High Plains, 15-percent wind probabilities were added over parts of eastern CO. Here, ample diurnal heating/steepening low-level lapse rates has increased confidence in a slightly greater concentration of severe wind gusts -- especially with any clusters that evolve eastward into this evening. For more details, reference MCD #1956 and Severe Thunderstorm Watch #639. Farther north, the Slight Risk was expanded slightly eastward into western ND, where filtered diurnal heating and an eventual increase in the low-level jet should favor localized upscale growth and a continued severe-wind risk into tonight. See MCD #1958 for additional details. From portions of the Northeast into the Mid-Atlantic, scattered thunderstorms will continue tracking eastward along/ahead of a cold front through the afternoon, posing a risk of locally damaging wind gusts. The Marginal Risk was trimmed slightly behind the front in the Northeast. For details, see MCDs #1955/1957. ..Weinman.. 08/19/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Mon Aug 19 2024/ ...High Plains... Moderately strong westerly mid-level winds are present today from MT to CO, with several weak perturbations noted on water vapor imagery within the flow. Steep mid-level lapse rates and dewpoints in the 60s will lead to a narrow corridor of favorable CAPE later today for strong/severe thunderstorm development. Clusters of convection will form over the mountains and foothills of CO/WY and spread eastward into the higher instability axis. Other areas of storms are expected to develop over the Black Hills, and across parts of eastern MT. Large hail is the main concern with these storms, although the risk of isolated damaging wind will also increase during the late afternoon and evening as outflows congeal. ...Western MT... 12z model guidance continues to agree on the development of scattered thunderstorms this afternoon over the mountains of western MT. This region will be on the eastern fringe of stronger flow aloft, and where full sunshine will aid in destabilization and steepening of low-level lapse rates. As storms move off the higher terrain, merging outflows may result in strong/damaging wind gusts in the more organized storm clusters. One mitigating factor for severe in this region would be if the persistent cloud cover east of the mountains limits destabilization. ...Southeast VA/Northeast NC... Strong daytime heating is occurring today over parts of southeast VA and northeast NC, where dewpoints in the upper 60s and 70s will yield MLCAPE values around 2000 J/kg. Scattered afternoon thunderstorms are expected. Low and mid-level winds are relatively weak today, suggesting that storms will struggle to organize. However, given the extent of heating, a few cells may occasionally pose a risk of gusty winds through the early evening. ...New England... An upper trough is moving across the Northeast US today, with the associated surface cold front tracking eastward across much of New England this afternoon. Scattered thunderstorms are expected along the front. Visible satellite imagery suggest considerable cloud cover over this region, limiting daytime heating and suppressing steeper low-level lapse rates. This should lessen the overall severe threat today. Nevertheless, a few storms could produce gusty winds and/or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 19 2024 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS...AND OVER WESTERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are possible across portions of the northern and central High Plains, and over western Montana into tonight. Large hail and severe gusts are the primary hazards. ...20Z Update... Within the Slight Risk area over the central High Plains, 15-percent wind probabilities were added over parts of eastern CO. Here, ample diurnal heating/steepening low-level lapse rates has increased confidence in a slightly greater concentration of severe wind gusts -- especially with any clusters that evolve eastward into this evening. For more details, reference MCD #1956 and Severe Thunderstorm Watch #639. Farther north, the Slight Risk was expanded slightly eastward into western ND, where filtered diurnal heating and an eventual increase in the low-level jet should favor localized upscale growth and a continued severe-wind risk into tonight. See MCD #1958 for additional details. From portions of the Northeast into the Mid-Atlantic, scattered thunderstorms will continue tracking eastward along/ahead of a cold front through the afternoon, posing a risk of locally damaging wind gusts. The Marginal Risk was trimmed slightly behind the front in the Northeast. For details, see MCDs #1955/1957. ..Weinman.. 08/19/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Mon Aug 19 2024/ ...High Plains... Moderately strong westerly mid-level winds are present today from MT to CO, with several weak perturbations noted on water vapor imagery within the flow. Steep mid-level lapse rates and dewpoints in the 60s will lead to a narrow corridor of favorable CAPE later today for strong/severe thunderstorm development. Clusters of convection will form over the mountains and foothills of CO/WY and spread eastward into the higher instability axis. Other areas of storms are expected to develop over the Black Hills, and across parts of eastern MT. Large hail is the main concern with these storms, although the risk of isolated damaging wind will also increase during the late afternoon and evening as outflows congeal. ...Western MT... 12z model guidance continues to agree on the development of scattered thunderstorms this afternoon over the mountains of western MT. This region will be on the eastern fringe of stronger flow aloft, and where full sunshine will aid in destabilization and steepening of low-level lapse rates. As storms move off the higher terrain, merging outflows may result in strong/damaging wind gusts in the more organized storm clusters. One mitigating factor for severe in this region would be if the persistent cloud cover east of the mountains limits destabilization. ...Southeast VA/Northeast NC... Strong daytime heating is occurring today over parts of southeast VA and northeast NC, where dewpoints in the upper 60s and 70s will yield MLCAPE values around 2000 J/kg. Scattered afternoon thunderstorms are expected. Low and mid-level winds are relatively weak today, suggesting that storms will struggle to organize. However, given the extent of heating, a few cells may occasionally pose a risk of gusty winds through the early evening. ...New England... An upper trough is moving across the Northeast US today, with the associated surface cold front tracking eastward across much of New England this afternoon. Scattered thunderstorms are expected along the front. Visible satellite imagery suggest considerable cloud cover over this region, limiting daytime heating and suppressing steeper low-level lapse rates. This should lessen the overall severe threat today. Nevertheless, a few storms could produce gusty winds and/or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 19 2024 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS...AND OVER WESTERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are possible across portions of the northern and central High Plains, and over western Montana into tonight. Large hail and severe gusts are the primary hazards. ...20Z Update... Within the Slight Risk area over the central High Plains, 15-percent wind probabilities were added over parts of eastern CO. Here, ample diurnal heating/steepening low-level lapse rates has increased confidence in a slightly greater concentration of severe wind gusts -- especially with any clusters that evolve eastward into this evening. For more details, reference MCD #1956 and Severe Thunderstorm Watch #639. Farther north, the Slight Risk was expanded slightly eastward into western ND, where filtered diurnal heating and an eventual increase in the low-level jet should favor localized upscale growth and a continued severe-wind risk into tonight. See MCD #1958 for additional details. From portions of the Northeast into the Mid-Atlantic, scattered thunderstorms will continue tracking eastward along/ahead of a cold front through the afternoon, posing a risk of locally damaging wind gusts. The Marginal Risk was trimmed slightly behind the front in the Northeast. For details, see MCDs #1955/1957. ..Weinman.. 08/19/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Mon Aug 19 2024/ ...High Plains... Moderately strong westerly mid-level winds are present today from MT to CO, with several weak perturbations noted on water vapor imagery within the flow. Steep mid-level lapse rates and dewpoints in the 60s will lead to a narrow corridor of favorable CAPE later today for strong/severe thunderstorm development. Clusters of convection will form over the mountains and foothills of CO/WY and spread eastward into the higher instability axis. Other areas of storms are expected to develop over the Black Hills, and across parts of eastern MT. Large hail is the main concern with these storms, although the risk of isolated damaging wind will also increase during the late afternoon and evening as outflows congeal. ...Western MT... 12z model guidance continues to agree on the development of scattered thunderstorms this afternoon over the mountains of western MT. This region will be on the eastern fringe of stronger flow aloft, and where full sunshine will aid in destabilization and steepening of low-level lapse rates. As storms move off the higher terrain, merging outflows may result in strong/damaging wind gusts in the more organized storm clusters. One mitigating factor for severe in this region would be if the persistent cloud cover east of the mountains limits destabilization. ...Southeast VA/Northeast NC... Strong daytime heating is occurring today over parts of southeast VA and northeast NC, where dewpoints in the upper 60s and 70s will yield MLCAPE values around 2000 J/kg. Scattered afternoon thunderstorms are expected. Low and mid-level winds are relatively weak today, suggesting that storms will struggle to organize. However, given the extent of heating, a few cells may occasionally pose a risk of gusty winds through the early evening. ...New England... An upper trough is moving across the Northeast US today, with the associated surface cold front tracking eastward across much of New England this afternoon. Scattered thunderstorms are expected along the front. Visible satellite imagery suggest considerable cloud cover over this region, limiting daytime heating and suppressing steeper low-level lapse rates. This should lessen the overall severe threat today. Nevertheless, a few storms could produce gusty winds and/or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 19 2024 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS...AND OVER WESTERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are possible across portions of the northern and central High Plains, and over western Montana into tonight. Large hail and severe gusts are the primary hazards. ...20Z Update... Within the Slight Risk area over the central High Plains, 15-percent wind probabilities were added over parts of eastern CO. Here, ample diurnal heating/steepening low-level lapse rates has increased confidence in a slightly greater concentration of severe wind gusts -- especially with any clusters that evolve eastward into this evening. For more details, reference MCD #1956 and Severe Thunderstorm Watch #639. Farther north, the Slight Risk was expanded slightly eastward into western ND, where filtered diurnal heating and an eventual increase in the low-level jet should favor localized upscale growth and a continued severe-wind risk into tonight. See MCD #1958 for additional details. From portions of the Northeast into the Mid-Atlantic, scattered thunderstorms will continue tracking eastward along/ahead of a cold front through the afternoon, posing a risk of locally damaging wind gusts. The Marginal Risk was trimmed slightly behind the front in the Northeast. For details, see MCDs #1955/1957. ..Weinman.. 08/19/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Mon Aug 19 2024/ ...High Plains... Moderately strong westerly mid-level winds are present today from MT to CO, with several weak perturbations noted on water vapor imagery within the flow. Steep mid-level lapse rates and dewpoints in the 60s will lead to a narrow corridor of favorable CAPE later today for strong/severe thunderstorm development. Clusters of convection will form over the mountains and foothills of CO/WY and spread eastward into the higher instability axis. Other areas of storms are expected to develop over the Black Hills, and across parts of eastern MT. Large hail is the main concern with these storms, although the risk of isolated damaging wind will also increase during the late afternoon and evening as outflows congeal. ...Western MT... 12z model guidance continues to agree on the development of scattered thunderstorms this afternoon over the mountains of western MT. This region will be on the eastern fringe of stronger flow aloft, and where full sunshine will aid in destabilization and steepening of low-level lapse rates. As storms move off the higher terrain, merging outflows may result in strong/damaging wind gusts in the more organized storm clusters. One mitigating factor for severe in this region would be if the persistent cloud cover east of the mountains limits destabilization. ...Southeast VA/Northeast NC... Strong daytime heating is occurring today over parts of southeast VA and northeast NC, where dewpoints in the upper 60s and 70s will yield MLCAPE values around 2000 J/kg. Scattered afternoon thunderstorms are expected. Low and mid-level winds are relatively weak today, suggesting that storms will struggle to organize. However, given the extent of heating, a few cells may occasionally pose a risk of gusty winds through the early evening. ...New England... An upper trough is moving across the Northeast US today, with the associated surface cold front tracking eastward across much of New England this afternoon. Scattered thunderstorms are expected along the front. Visible satellite imagery suggest considerable cloud cover over this region, limiting daytime heating and suppressing steeper low-level lapse rates. This should lessen the overall severe threat today. Nevertheless, a few storms could produce gusty winds and/or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 19 2024 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS...AND OVER WESTERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are possible across portions of the northern and central High Plains, and over western Montana into tonight. Large hail and severe gusts are the primary hazards. ...20Z Update... Within the Slight Risk area over the central High Plains, 15-percent wind probabilities were added over parts of eastern CO. Here, ample diurnal heating/steepening low-level lapse rates has increased confidence in a slightly greater concentration of severe wind gusts -- especially with any clusters that evolve eastward into this evening. For more details, reference MCD #1956 and Severe Thunderstorm Watch #639. Farther north, the Slight Risk was expanded slightly eastward into western ND, where filtered diurnal heating and an eventual increase in the low-level jet should favor localized upscale growth and a continued severe-wind risk into tonight. See MCD #1958 for additional details. From portions of the Northeast into the Mid-Atlantic, scattered thunderstorms will continue tracking eastward along/ahead of a cold front through the afternoon, posing a risk of locally damaging wind gusts. The Marginal Risk was trimmed slightly behind the front in the Northeast. For details, see MCDs #1955/1957. ..Weinman.. 08/19/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Mon Aug 19 2024/ ...High Plains... Moderately strong westerly mid-level winds are present today from MT to CO, with several weak perturbations noted on water vapor imagery within the flow. Steep mid-level lapse rates and dewpoints in the 60s will lead to a narrow corridor of favorable CAPE later today for strong/severe thunderstorm development. Clusters of convection will form over the mountains and foothills of CO/WY and spread eastward into the higher instability axis. Other areas of storms are expected to develop over the Black Hills, and across parts of eastern MT. Large hail is the main concern with these storms, although the risk of isolated damaging wind will also increase during the late afternoon and evening as outflows congeal. ...Western MT... 12z model guidance continues to agree on the development of scattered thunderstorms this afternoon over the mountains of western MT. This region will be on the eastern fringe of stronger flow aloft, and where full sunshine will aid in destabilization and steepening of low-level lapse rates. As storms move off the higher terrain, merging outflows may result in strong/damaging wind gusts in the more organized storm clusters. One mitigating factor for severe in this region would be if the persistent cloud cover east of the mountains limits destabilization. ...Southeast VA/Northeast NC... Strong daytime heating is occurring today over parts of southeast VA and northeast NC, where dewpoints in the upper 60s and 70s will yield MLCAPE values around 2000 J/kg. Scattered afternoon thunderstorms are expected. Low and mid-level winds are relatively weak today, suggesting that storms will struggle to organize. However, given the extent of heating, a few cells may occasionally pose a risk of gusty winds through the early evening. ...New England... An upper trough is moving across the Northeast US today, with the associated surface cold front tracking eastward across much of New England this afternoon. Scattered thunderstorms are expected along the front. Visible satellite imagery suggest considerable cloud cover over this region, limiting daytime heating and suppressing steeper low-level lapse rates. This should lessen the overall severe threat today. Nevertheless, a few storms could produce gusty winds and/or hail. Read more