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MD 1836 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EASTERN MONTANA...FAR WESTERN NORTH DAKOTA
Mesoscale Discussion 1836 NWS Storm Prediction Center Norman OK 0628 PM CDT Thu Aug 22 2019 Areas affected...Portions of eastern Montana...far western North Dakota Concerning...Severe potential...Watch unlikely Valid 222328Z - 230130Z Probability of Watch Issuance...20 percent SUMMARY...Isolated to scattered thunderstorms are likely this evening with latest observational/model trends suggesting development by 7-8 PM MDT. Large hail and strong/severe wind gusts will be possible with these storms. Overall lack of storm organization will likely preclude WW issuance. DISCUSSION...Visible satellite imagery shows an increase in agitated cumulus from the northern Big Horn vicinity and points northward into eastern Montana. Convergence within the central/eastern Montana surface trough coupled with increasing mid-level ascent will lead to isolated to scattered storm development by early evening. Deep-layer shear is currently relatively weak across eastern Montana and is not expected to increase significantly this evening as the mid-level jet is expected to be displaced south/southwestward of the discussion area. Still, marginal effective shear (20-30 kts) and steep mid-level lapse rates of 7.5-8 C/km will support semi-organized storms capable of large hail. Strong/severe wind gusts will also be possible as low-level lapse rates have become very steep with strong heating/mixing this afternoon in eastern Montana. A WW is not anticipated given the overall lack of storm organization expected. ..Wendt/Grams.. 08/22/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...UNR...BYZ...GGW... LAT...LON 45390645 47230734 48740738 48970636 48900432 48660401 46390362 45430382 45110469 45130575 45390645 Read more

000
ABPZ20 KNHC 222325
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Thu Aug 22 2019

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Storm Ivo, located several hundred miles south-southwest of the
southern tip of the Baja California peninsula.

A surface trough located a little less than 1200 miles
east-southeast of the Big Island of Hawaii continues to produce
disorganized cloudiness and showers. Environmental conditions could
become conducive for some development, in a few days, in the central
Pacific basin, well to the east of Hawaii, while the system is
moving slowly northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Roberts

The Bandera County River Authority and Groundwater District issued a warning cautioning the public about recreational contact with the Medina and Sabinal rivers, due to poor water quality. As of Aug. 15, the river authority strongly advised that people avoid recreational contact, including swimming, in the Medina and Sabinal rivers and their tributaries because heat and low to no flows have allowed the proliferation of potentially harmful organisms in the water. Bandera Bulletin (Texas), Aug. 21, 2019

No watches are valid as of Thu Aug 22 22:32:03 UTC 2019.

MD 1835 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHERN/CENTRAL OKLAHOMA AND NORTHWESTERN ARKANSAS
Mesoscale Discussion 1835 NWS Storm Prediction Center Norman OK 0517 PM CDT Thu Aug 22 2019 Areas affected...Portions of southern/central Oklahoma and northwestern Arkansas Concerning...Severe potential...Watch unlikely Valid 222217Z - 230015Z Probability of Watch Issuance...5 percent SUMMARY...A few isolated strong to near severe wind gusts possible with storms along old outflow boundary. Threat should remain isolated and diminish after sunset. No WW is anticipated. DISCUSSION...An increase in convection along a residual outflow boundary across southwestern/central Oklahoma into northwestern Arkansas has been noted in last hour. With 1000-1200 J/kg DCAPE, a few isolated strong wind gusts are possible -- a 50 mph gust was recorded by the Frederick mesonet site roughly 90 minutes ago -- until convection decreases in intensity after sunset. Storms will remain relatively disorganized with only 20 to perhaps 30 kts of effective deep-layer shear along/near the boundary. Greatest threat for strong gusts will be with any clusters of storms that congeal and form a semi-organized cold pool. Isolated nature and short duration of the threat will likely preclude any watch issuance this evening. ..Wendt/Grams.. 08/22/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...TSA...OUN... LAT...LON 34969887 35449726 36089460 36189385 35879347 35349392 34669646 34529802 34599874 34789887 34969887 Read more

No Mesoscale Discussions are in effect as of Thu Aug 22 21:54:01 UTC 2019.

Mail delivery on Vermilion Lake was affected by the low lake level as some docks were inaccessible, due to shallow water. Some mailboat customers were given notices, alerting them to the interruption in service. Dozens of residences have water access mail delivery. Tower Timberjay (Minn.), Aug. 22, 2019

The low level of Lake Vermilion has caused boat damage for boaters who were unaware of how shallow the lake had become. An employee at a boat repair business noted that they were selling a propeller per day as people damage theirs in the lake. He urged boaters to be especially careful navigating the lake as new hazardous areas emerge. Tower Timberjay (Minn.), Aug. 22, 2019

5-Day Uncertainty Track last updated Thu, 22 Aug 2019 20:33:49 GMT


Wind Speed Probabilities last updated Thu, 22 Aug 2019 21:31:08 GMT

Issued at 300 PM MDT Thu Aug 22 2019 000 WTPZ45 KNHC 222032 TCDEP5 Tropical Storm Ivo Discussion Number 6 NWS National Hurricane Center Miami FL EP102019 300 PM MDT Thu Aug 22 2019 Visible satellite images show a bit of a surprise with Ivo this afternoon. The system is not as well organized as earlier microwave data displayed, with the center almost partially exposed on the northeastern side of the central dense overcast. The initial wind speed is held at 55 kt, which is in line with TAFB/SAB estimates and 50-55 kt ASCAT-C winds. With shear still forecast to increase overnight, only slight intensification of Ivo is anticipated. While Ivo could still become a hurricane, almost all of the guidance has backed off on this cycle. Weakening should begin over the weekend when the storm moves over progressive cooler waters. Convection is likely to dissipate in about 72 hours, and post-tropical status of Ivo is forecast at that time. Overall the new forecast is reduced about 5 kt from the previous one, near or slightly above the model consensus. Ivo has turned west-northwestward, or 295/8 kt. The storm should turn to the northwest tomorrow and north-northwest on Saturday due to steering from a mid-level ridge over Mexico. Model guidance is coming into better agreement on this course, with fairly small variations. Overall, the small eastward trend seen in the guidance continues, and the new NHC prediction is shifted a little eastward at long range. Still, none of the guidance still show a direct tropical cyclone threat to Mexico at this time. It is worth noting that the current size of Ivo has been greatly increased due to the ASCAT-C data. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 16.1N 114.1W 55 KT 65 MPH 12H 23/0600Z 17.0N 114.9W 60 KT 70 MPH 24H 23/1800Z 18.5N 116.0W 60 KT 70 MPH 36H 24/0600Z 20.2N 116.9W 55 KT 65 MPH 48H 24/1800Z 22.0N 117.8W 45 KT 50 MPH 72H 25/1800Z 25.9N 119.7W 35 KT 40 MPH...POST-TROPICAL 96H 26/1800Z 28.5N 121.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 27/1800Z...DISSIPATED $$ Forecaster Blake

Issued at 2100 UTC THU AUG 22 2019 000 FOPZ15 KNHC 222032 PWSEP5 TROPICAL STORM IVO WIND SPEED PROBABILITIES NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102019 2100 UTC THU AUG 22 2019 AT 2100Z THE CENTER OF TROPICAL STORM IVO WAS LOCATED NEAR LATITUDE 16.1 NORTH...LONGITUDE 114.1 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 55 KTS...65 MPH...100 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 THU 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 THU 06Z FRI 18Z FRI 06Z SAT 18Z SAT 18Z SUN 18Z MON PERIODS TO TO TO TO TO TO TO 06Z FRI 18Z FRI 06Z SAT 18Z SAT 18Z SUN 18Z MON 18Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT IS GUADALUPE 34 X X( X) X( X) X( X) 1( 1) 3( 4) X( 4) ISLA SOCORRO 34 2 2( 4) X( 4) X( 4) X( 4) X( 4) X( 4) ISLA CLARION 34 19 48(67) 1(68) X(68) X(68) X(68) X(68) ISLA CLARION 50 X 13(13) X(13) X(13) X(13) X(13) X(13) ISLA CLARION 64 X 2( 2) X( 2) X( 2) X( 2) X( 2) X( 2) 15N 115W 34 9 3(12) 1(13) X(13) X(13) X(13) X(13) 20N 115W 34 3 18(21) 15(36) 1(37) X(37) X(37) X(37) 20N 115W 50 X 1( 1) 3( 4) X( 4) X( 4) X( 4) X( 4) 25N 115W 34 X X( X) 1( 1) 1( 2) 2( 4) X( 4) X( 4) 20N 120W 34 X 3( 3) 4( 7) 2( 9) 1(10) X(10) X(10) 25N 120W 34 X X( X) X( X) 2( 2) 27(29) 2(31) X(31) 25N 120W 50 X X( X) X( X) X( X) 5( 5) 1( 6) X( 6) 30N 120W 34 X X( X) X( X) X( X) 1( 1) 2( 3) X( 3) $$ FORECASTER BLAKE

Issued at 300 PM MDT Thu Aug 22 2019 000 WTPZ35 KNHC 222032 TCPEP5 BULLETIN Tropical Storm Ivo Advisory Number 6 NWS National Hurricane Center Miami FL EP102019 300 PM MDT Thu Aug 22 2019 ...IVO TURNING WEST-NORTHWESTWARD... SUMMARY OF 300 PM MDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...16.1N 114.1W ABOUT 545 MI...875 KM SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 300 PM MDT (2100 UTC), the center of Tropical Storm Ivo was located near latitude 16.1 North, longitude 114.1 West. Ivo is moving toward the west-northwest near 9 mph (15 km/h), and Ivo is forecast to turn to the northwest on Friday and move north-northwestward over the weekend. Maximum sustained winds remain near 65 mph (100 km/h) with higher gusts. Little change in strength is forecast through Friday with weakening likely to begin on Saturday. Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center. The estimated minimum central pressure is 996 mb (29.42 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 900 PM MDT. $$ Forecaster Blake

...IVO TURNING WEST-NORTHWESTWARD... As of 3:00 PM MDT Thu Aug 22 the center of Ivo was located near 16.1, -114.1 with movement WNW at 9 mph. The minimum central pressure was 996 mb with maximum sustained winds of about 65 mph.

Issued at 2100 UTC THU AUG 22 2019 000 WTPZ25 KNHC 222031 TCMEP5 TROPICAL STORM IVO FORECAST/ADVISORY NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102019 2100 UTC THU AUG 22 2019 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. TROPICAL STORM CENTER LOCATED NEAR 16.1N 114.1W AT 22/2100Z POSITION ACCURATE WITHIN 25 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 8 KT ESTIMATED MINIMUM CENTRAL PRESSURE 996 MB MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. 50 KT....... 30NE 40SE 30SW 0NW. 34 KT....... 60NE 90SE 60SW 30NW. 12 FT SEAS..150NE 120SE 30SW 30NW. 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 16.1N 114.1W AT 22/2100Z AT 22/1800Z CENTER WAS LOCATED NEAR 15.8N 113.8W FORECAST VALID 23/0600Z 17.0N 114.9W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 40SE 30SW 0NW. 34 KT... 70NE 90SE 60SW 40NW. FORECAST VALID 23/1800Z 18.5N 116.0W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 30SE 20SW 0NW. 34 KT... 90NE 90SE 70SW 50NW. FORECAST VALID 24/0600Z 20.2N 116.9W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 30NE 30SE 0SW 0NW. 34 KT... 80NE 90SE 60SW 60NW. FORECAST VALID 24/1800Z 22.0N 117.8W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 80NE 80SE 50SW 60NW. FORECAST VALID 25/1800Z 25.9N 119.7W...POST-TROPICAL MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 50NE 40SE 30SW 40NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 150 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 26/1800Z 28.5N 121.0W...POST-TROP/REMNT LOW MAX WIND 20 KT...GUSTS 30 KT. OUTLOOK VALID 27/1800Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 16.1N 114.1W NEXT ADVISORY AT 23/0300Z $$ FORECASTER BLAKE

MD 1834 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHEAST COLORADO...SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE
Mesoscale Discussion 1834 NWS Storm Prediction Center Norman OK 0311 PM CDT Thu Aug 22 2019 Areas affected...portions of northeast Colorado...southeast Wyoming and the Nebraska Panhandle Concerning...Severe potential...Watch unlikely Valid 222011Z - 222145Z Probability of Watch Issuance...20 percent SUMMARY...Isolated strong/severe thunderstorms are anticipated this afternoon, with a risk for large hail and strong wind gusts. A watch is not currently anticipated. DISCUSSION...Regional radar and satellite imagery reveals an increase in showers/thunderstorms from the Denver Metro north into southeast WY, aided by moist southeasterly low-level flow and strong diurnal heating. Although mid-level flow is generally at or below 25 kts, the strength of the low-level flow is contributing to 25-35 kts of effective shear, and this should prove sufficient for some updraft organization as storms move east of the higher terrain through this evening. In the presence of moderate MLCAPE and steep low- and mid-level lapse rates, isolated stronger storms will be capable of severe hail and strong wind gusts. As storms merge into a small cluster this evening, some risk for strong winds may continue to exist within a more localized area. Convective trends will continue to be monitored, however a watch is not currently anticipated. ..Bunting/Guyer.. 08/22/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GLD...BOU...CYS... LAT...LON 39330315 39230457 39620509 40420542 40940543 41390521 41680502 41870467 41960394 41710326 40830262 39900247 39330315 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 22 2019 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS...AND FROM PORTIONS OF THE NORTHEAST AND MID ATLANTIC/CAROLINAS WESTWARD TO OKLAHOMA/NORTH TEXAS... ...SUMMARY... Isolated damaging winds remain possible this afternoon and evening from the southern Plains and Mid-South to the Mid-Atlantic States. Isolated severe hail and wind are also possible over the northern and central High Plains. ...Discussion... Little change appears necessary to the ongoing outlook areas and/or reasoning at this time, with convective weather largely evolving as anticipated. As such, aside from a few line tweaks, no changes are being implemented to the outlook in this update. ..Goss.. 08/22/2019 .PREV DISCUSSION... /ISSUED 1136 AM CDT Thu Aug 22 2019/ ...Mid-Atlantic States/Carolinas... A belt of cyclonically curved/moderately strong westerlies aloft will persist over the Upper Ohio Valley and Mid-Atlantic region, with a cold front gradually progressing southeastward across these regions through tonight. Thunderstorms are expected to develop/increase over the mountains and/or in association with ongoing persistent clusters. As low-level lapse rates steepen, damaging winds will be the primary risk. A few sustained/semi-organized clusters of storms may materialize this afternoon, particularly from south-central Pennsylvania southward to near/east of the Blue Ridge in Virginia/Northern Carolina. However, current thinking is that the overall severe storm coverage/risk magnitude will be a bit lower as compared to prior days across the region. ...Southeast Wyoming/Central High Plains... To the north of an eastern Colorado-centered surface low, low-level upslope flow and differential heating in vicinity of the higher terrain is likely to contribute to isolated thunderstorm development this afternoon. Storms should intensify as they move east-southeastward within a moist/increasingly unstable environment. A few instances of isolated severe hail will initially be possible. Storms may gradually cluster with localized severe-caliber wind gust potential this evening across the southern Nebraska Panhandle/northeast Colorado vicinity, and possibly southwest Nebraska/northwest Kansas. ...Southern/eastern Montana to northern High Plains... Isolated to scattered thunderstorms are expected to develop across this area during the afternoon, and into evening with eastward extent. Isolated severe gusts/hail are the main concerns. A relative concentration of convection is possible during about 00Z-06Z across portions of eastern Montana and perhaps northeastern Wyoming. During that time frame, some of the stronger low-level mass response and convergence (related to the approaching shortwave trough), and perhaps the leading fringe of mid/upper synoptic forcing, will impinge upon a narrow plume of relatively maximized buoyancy and boundary-layer moisture. Pre-convective MLCAPE of 1000-2000 J/kg is possible this evening near an axis from RAP-GGW, amidst well-mixed subcloud layers supporting strong-severe gust potential. However, weak mid/upper-level winds suggest that severe potential should remain fairly disorganized and/or short-lived. ...Southern Plains to Mid-South/Tennessee Valley... Within a moist/unstable environment, surface-based thunderstorm development later this afternoon will be focused along zones of residual outflow/differential heating. While weak westerlies will generally prevail, ample heating/buoyancy could support localized severe-caliber downdrafts late this afternoon/early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 22 2019 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS...AND FROM PORTIONS OF THE NORTHEAST AND MID ATLANTIC/CAROLINAS WESTWARD TO OKLAHOMA/NORTH TEXAS... ...SUMMARY... Isolated damaging winds remain possible this afternoon and evening from the southern Plains and Mid-South to the Mid-Atlantic States. Isolated severe hail and wind are also possible over the northern and central High Plains. ...Discussion... Little change appears necessary to the ongoing outlook areas and/or reasoning at this time, with convective weather largely evolving as anticipated. As such, aside from a few line tweaks, no changes are being implemented to the outlook in this update. ..Goss.. 08/22/2019 .PREV DISCUSSION... /ISSUED 1136 AM CDT Thu Aug 22 2019/ ...Mid-Atlantic States/Carolinas... A belt of cyclonically curved/moderately strong westerlies aloft will persist over the Upper Ohio Valley and Mid-Atlantic region, with a cold front gradually progressing southeastward across these regions through tonight. Thunderstorms are expected to develop/increase over the mountains and/or in association with ongoing persistent clusters. As low-level lapse rates steepen, damaging winds will be the primary risk. A few sustained/semi-organized clusters of storms may materialize this afternoon, particularly from south-central Pennsylvania southward to near/east of the Blue Ridge in Virginia/Northern Carolina. However, current thinking is that the overall severe storm coverage/risk magnitude will be a bit lower as compared to prior days across the region. ...Southeast Wyoming/Central High Plains... To the north of an eastern Colorado-centered surface low, low-level upslope flow and differential heating in vicinity of the higher terrain is likely to contribute to isolated thunderstorm development this afternoon. Storms should intensify as they move east-southeastward within a moist/increasingly unstable environment. A few instances of isolated severe hail will initially be possible. Storms may gradually cluster with localized severe-caliber wind gust potential this evening across the southern Nebraska Panhandle/northeast Colorado vicinity, and possibly southwest Nebraska/northwest Kansas. ...Southern/eastern Montana to northern High Plains... Isolated to scattered thunderstorms are expected to develop across this area during the afternoon, and into evening with eastward extent. Isolated severe gusts/hail are the main concerns. A relative concentration of convection is possible during about 00Z-06Z across portions of eastern Montana and perhaps northeastern Wyoming. During that time frame, some of the stronger low-level mass response and convergence (related to the approaching shortwave trough), and perhaps the leading fringe of mid/upper synoptic forcing, will impinge upon a narrow plume of relatively maximized buoyancy and boundary-layer moisture. Pre-convective MLCAPE of 1000-2000 J/kg is possible this evening near an axis from RAP-GGW, amidst well-mixed subcloud layers supporting strong-severe gust potential. However, weak mid/upper-level winds suggest that severe potential should remain fairly disorganized and/or short-lived. ...Southern Plains to Mid-South/Tennessee Valley... Within a moist/unstable environment, surface-based thunderstorm development later this afternoon will be focused along zones of residual outflow/differential heating. While weak westerlies will generally prevail, ample heating/buoyancy could support localized severe-caliber downdrafts late this afternoon/early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 22 2019 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS...AND FROM PORTIONS OF THE NORTHEAST AND MID ATLANTIC/CAROLINAS WESTWARD TO OKLAHOMA/NORTH TEXAS... ...SUMMARY... Isolated damaging winds remain possible this afternoon and evening from the southern Plains and Mid-South to the Mid-Atlantic States. Isolated severe hail and wind are also possible over the northern and central High Plains. ...Discussion... Little change appears necessary to the ongoing outlook areas and/or reasoning at this time, with convective weather largely evolving as anticipated. As such, aside from a few line tweaks, no changes are being implemented to the outlook in this update. ..Goss.. 08/22/2019 .PREV DISCUSSION... /ISSUED 1136 AM CDT Thu Aug 22 2019/ ...Mid-Atlantic States/Carolinas... A belt of cyclonically curved/moderately strong westerlies aloft will persist over the Upper Ohio Valley and Mid-Atlantic region, with a cold front gradually progressing southeastward across these regions through tonight. Thunderstorms are expected to develop/increase over the mountains and/or in association with ongoing persistent clusters. As low-level lapse rates steepen, damaging winds will be the primary risk. A few sustained/semi-organized clusters of storms may materialize this afternoon, particularly from south-central Pennsylvania southward to near/east of the Blue Ridge in Virginia/Northern Carolina. However, current thinking is that the overall severe storm coverage/risk magnitude will be a bit lower as compared to prior days across the region. ...Southeast Wyoming/Central High Plains... To the north of an eastern Colorado-centered surface low, low-level upslope flow and differential heating in vicinity of the higher terrain is likely to contribute to isolated thunderstorm development this afternoon. Storms should intensify as they move east-southeastward within a moist/increasingly unstable environment. A few instances of isolated severe hail will initially be possible. Storms may gradually cluster with localized severe-caliber wind gust potential this evening across the southern Nebraska Panhandle/northeast Colorado vicinity, and possibly southwest Nebraska/northwest Kansas. ...Southern/eastern Montana to northern High Plains... Isolated to scattered thunderstorms are expected to develop across this area during the afternoon, and into evening with eastward extent. Isolated severe gusts/hail are the main concerns. A relative concentration of convection is possible during about 00Z-06Z across portions of eastern Montana and perhaps northeastern Wyoming. During that time frame, some of the stronger low-level mass response and convergence (related to the approaching shortwave trough), and perhaps the leading fringe of mid/upper synoptic forcing, will impinge upon a narrow plume of relatively maximized buoyancy and boundary-layer moisture. Pre-convective MLCAPE of 1000-2000 J/kg is possible this evening near an axis from RAP-GGW, amidst well-mixed subcloud layers supporting strong-severe gust potential. However, weak mid/upper-level winds suggest that severe potential should remain fairly disorganized and/or short-lived. ...Southern Plains to Mid-South/Tennessee Valley... Within a moist/unstable environment, surface-based thunderstorm development later this afternoon will be focused along zones of residual outflow/differential heating. While weak westerlies will generally prevail, ample heating/buoyancy could support localized severe-caliber downdrafts late this afternoon/early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 22 2019 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS...AND FROM PORTIONS OF THE NORTHEAST AND MID ATLANTIC/CAROLINAS WESTWARD TO OKLAHOMA/NORTH TEXAS... ...SUMMARY... Isolated damaging winds remain possible this afternoon and evening from the southern Plains and Mid-South to the Mid-Atlantic States. Isolated severe hail and wind are also possible over the northern and central High Plains. ...Discussion... Little change appears necessary to the ongoing outlook areas and/or reasoning at this time, with convective weather largely evolving as anticipated. As such, aside from a few line tweaks, no changes are being implemented to the outlook in this update. ..Goss.. 08/22/2019 .PREV DISCUSSION... /ISSUED 1136 AM CDT Thu Aug 22 2019/ ...Mid-Atlantic States/Carolinas... A belt of cyclonically curved/moderately strong westerlies aloft will persist over the Upper Ohio Valley and Mid-Atlantic region, with a cold front gradually progressing southeastward across these regions through tonight. Thunderstorms are expected to develop/increase over the mountains and/or in association with ongoing persistent clusters. As low-level lapse rates steepen, damaging winds will be the primary risk. A few sustained/semi-organized clusters of storms may materialize this afternoon, particularly from south-central Pennsylvania southward to near/east of the Blue Ridge in Virginia/Northern Carolina. However, current thinking is that the overall severe storm coverage/risk magnitude will be a bit lower as compared to prior days across the region. ...Southeast Wyoming/Central High Plains... To the north of an eastern Colorado-centered surface low, low-level upslope flow and differential heating in vicinity of the higher terrain is likely to contribute to isolated thunderstorm development this afternoon. Storms should intensify as they move east-southeastward within a moist/increasingly unstable environment. A few instances of isolated severe hail will initially be possible. Storms may gradually cluster with localized severe-caliber wind gust potential this evening across the southern Nebraska Panhandle/northeast Colorado vicinity, and possibly southwest Nebraska/northwest Kansas. ...Southern/eastern Montana to northern High Plains... Isolated to scattered thunderstorms are expected to develop across this area during the afternoon, and into evening with eastward extent. Isolated severe gusts/hail are the main concerns. A relative concentration of convection is possible during about 00Z-06Z across portions of eastern Montana and perhaps northeastern Wyoming. During that time frame, some of the stronger low-level mass response and convergence (related to the approaching shortwave trough), and perhaps the leading fringe of mid/upper synoptic forcing, will impinge upon a narrow plume of relatively maximized buoyancy and boundary-layer moisture. Pre-convective MLCAPE of 1000-2000 J/kg is possible this evening near an axis from RAP-GGW, amidst well-mixed subcloud layers supporting strong-severe gust potential. However, weak mid/upper-level winds suggest that severe potential should remain fairly disorganized and/or short-lived. ...Southern Plains to Mid-South/Tennessee Valley... Within a moist/unstable environment, surface-based thunderstorm development later this afternoon will be focused along zones of residual outflow/differential heating. While weak westerlies will generally prevail, ample heating/buoyancy could support localized severe-caliber downdrafts late this afternoon/early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Thu Aug 22 2019 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS...AND FROM PORTIONS OF THE NORTHEAST AND MID ATLANTIC/CAROLINAS WESTWARD TO OKLAHOMA/NORTH TEXAS... ...SUMMARY... Isolated damaging winds remain possible this afternoon and evening from the southern Plains and Mid-South to the Mid-Atlantic States. Isolated severe hail and wind are also possible over the northern and central High Plains. ...Discussion... Little change appears necessary to the ongoing outlook areas and/or reasoning at this time, with convective weather largely evolving as anticipated. As such, aside from a few line tweaks, no changes are being implemented to the outlook in this update. ..Goss.. 08/22/2019 .PREV DISCUSSION... /ISSUED 1136 AM CDT Thu Aug 22 2019/ ...Mid-Atlantic States/Carolinas... A belt of cyclonically curved/moderately strong westerlies aloft will persist over the Upper Ohio Valley and Mid-Atlantic region, with a cold front gradually progressing southeastward across these regions through tonight. Thunderstorms are expected to develop/increase over the mountains and/or in association with ongoing persistent clusters. As low-level lapse rates steepen, damaging winds will be the primary risk. A few sustained/semi-organized clusters of storms may materialize this afternoon, particularly from south-central Pennsylvania southward to near/east of the Blue Ridge in Virginia/Northern Carolina. However, current thinking is that the overall severe storm coverage/risk magnitude will be a bit lower as compared to prior days across the region. ...Southeast Wyoming/Central High Plains... To the north of an eastern Colorado-centered surface low, low-level upslope flow and differential heating in vicinity of the higher terrain is likely to contribute to isolated thunderstorm development this afternoon. Storms should intensify as they move east-southeastward within a moist/increasingly unstable environment. A few instances of isolated severe hail will initially be possible. Storms may gradually cluster with localized severe-caliber wind gust potential this evening across the southern Nebraska Panhandle/northeast Colorado vicinity, and possibly southwest Nebraska/northwest Kansas. ...Southern/eastern Montana to northern High Plains... Isolated to scattered thunderstorms are expected to develop across this area during the afternoon, and into evening with eastward extent. Isolated severe gusts/hail are the main concerns. A relative concentration of convection is possible during about 00Z-06Z across portions of eastern Montana and perhaps northeastern Wyoming. During that time frame, some of the stronger low-level mass response and convergence (related to the approaching shortwave trough), and perhaps the leading fringe of mid/upper synoptic forcing, will impinge upon a narrow plume of relatively maximized buoyancy and boundary-layer moisture. Pre-convective MLCAPE of 1000-2000 J/kg is possible this evening near an axis from RAP-GGW, amidst well-mixed subcloud layers supporting strong-severe gust potential. However, weak mid/upper-level winds suggest that severe potential should remain fairly disorganized and/or short-lived. ...Southern Plains to Mid-South/Tennessee Valley... Within a moist/unstable environment, surface-based thunderstorm development later this afternoon will be focused along zones of residual outflow/differential heating. While weak westerlies will generally prevail, ample heating/buoyancy could support localized severe-caliber downdrafts late this afternoon/early evening. Read more