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5-Day Uncertainty Track last updated Tue, 20 Aug 2024 08:42:39 GMT


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Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0338 AM CDT Tue Aug 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... Heights within the persistent central U.S. upper-level ridge are forecast to rise from Friday to Sunday, as a mid-level trough moves through the western U.S. An axis of maximized low-level moisture and instability is forecast to remain over the central and northern Plains extending south-southeastward into the mid Missouri Valley. Thunderstorm development, with a potential severe threat, will be possible across parts of this unstable airmass each afternoon and evening. Subsidence associated with the upper-level ridge will be a negative factor, which is expected to keep the severe threat isolated and marginal through the weekend. ...Monday/Day 7 and Tuesday/Day 8... The medium-range models are finally in agreement concerning the timing of an upper-level trough, which is forecast to move through the northern Plains on Monday. Ahead of this trough, a moist and unstable airmass is forecast from the mid Missouri Valley northeastward into the western Great Lakes. Thunderstorms are expected to develop ahead of the trough over parts of the Minnesota and Wisconsin, with more isolated convection southward into Iowa. Strong instability and moderate deep-layer shear should be favorable for a severe threat, with the most likely area in the upper Mississippi Valley Monday afternoon and evening. However, there is still uncertainty concerning the timing of the trough, and location of the instability axis on Monday. In addition, part of the airmass could remain capped. At this point, will not outlook a threat area. The potential severe threat is forecast to shift eastward into the central Great Lakes region on Tuesday, but could be isolated due to the presence of a northeastern U.S. upper-level ridge. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0338 AM CDT Tue Aug 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... Heights within the persistent central U.S. upper-level ridge are forecast to rise from Friday to Sunday, as a mid-level trough moves through the western U.S. An axis of maximized low-level moisture and instability is forecast to remain over the central and northern Plains extending south-southeastward into the mid Missouri Valley. Thunderstorm development, with a potential severe threat, will be possible across parts of this unstable airmass each afternoon and evening. Subsidence associated with the upper-level ridge will be a negative factor, which is expected to keep the severe threat isolated and marginal through the weekend. ...Monday/Day 7 and Tuesday/Day 8... The medium-range models are finally in agreement concerning the timing of an upper-level trough, which is forecast to move through the northern Plains on Monday. Ahead of this trough, a moist and unstable airmass is forecast from the mid Missouri Valley northeastward into the western Great Lakes. Thunderstorms are expected to develop ahead of the trough over parts of the Minnesota and Wisconsin, with more isolated convection southward into Iowa. Strong instability and moderate deep-layer shear should be favorable for a severe threat, with the most likely area in the upper Mississippi Valley Monday afternoon and evening. However, there is still uncertainty concerning the timing of the trough, and location of the instability axis on Monday. In addition, part of the airmass could remain capped. At this point, will not outlook a threat area. The potential severe threat is forecast to shift eastward into the central Great Lakes region on Tuesday, but could be isolated due to the presence of a northeastern U.S. upper-level ridge. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0338 AM CDT Tue Aug 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... Heights within the persistent central U.S. upper-level ridge are forecast to rise from Friday to Sunday, as a mid-level trough moves through the western U.S. An axis of maximized low-level moisture and instability is forecast to remain over the central and northern Plains extending south-southeastward into the mid Missouri Valley. Thunderstorm development, with a potential severe threat, will be possible across parts of this unstable airmass each afternoon and evening. Subsidence associated with the upper-level ridge will be a negative factor, which is expected to keep the severe threat isolated and marginal through the weekend. ...Monday/Day 7 and Tuesday/Day 8... The medium-range models are finally in agreement concerning the timing of an upper-level trough, which is forecast to move through the northern Plains on Monday. Ahead of this trough, a moist and unstable airmass is forecast from the mid Missouri Valley northeastward into the western Great Lakes. Thunderstorms are expected to develop ahead of the trough over parts of the Minnesota and Wisconsin, with more isolated convection southward into Iowa. Strong instability and moderate deep-layer shear should be favorable for a severe threat, with the most likely area in the upper Mississippi Valley Monday afternoon and evening. However, there is still uncertainty concerning the timing of the trough, and location of the instability axis on Monday. In addition, part of the airmass could remain capped. At this point, will not outlook a threat area. The potential severe threat is forecast to shift eastward into the central Great Lakes region on Tuesday, but could be isolated due to the presence of a northeastern U.S. upper-level ridge. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0338 AM CDT Tue Aug 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... Heights within the persistent central U.S. upper-level ridge are forecast to rise from Friday to Sunday, as a mid-level trough moves through the western U.S. An axis of maximized low-level moisture and instability is forecast to remain over the central and northern Plains extending south-southeastward into the mid Missouri Valley. Thunderstorm development, with a potential severe threat, will be possible across parts of this unstable airmass each afternoon and evening. Subsidence associated with the upper-level ridge will be a negative factor, which is expected to keep the severe threat isolated and marginal through the weekend. ...Monday/Day 7 and Tuesday/Day 8... The medium-range models are finally in agreement concerning the timing of an upper-level trough, which is forecast to move through the northern Plains on Monday. Ahead of this trough, a moist and unstable airmass is forecast from the mid Missouri Valley northeastward into the western Great Lakes. Thunderstorms are expected to develop ahead of the trough over parts of the Minnesota and Wisconsin, with more isolated convection southward into Iowa. Strong instability and moderate deep-layer shear should be favorable for a severe threat, with the most likely area in the upper Mississippi Valley Monday afternoon and evening. However, there is still uncertainty concerning the timing of the trough, and location of the instability axis on Monday. In addition, part of the airmass could remain capped. At this point, will not outlook a threat area. The potential severe threat is forecast to shift eastward into the central Great Lakes region on Tuesday, but could be isolated due to the presence of a northeastern U.S. upper-level ridge. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0338 AM CDT Tue Aug 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... Heights within the persistent central U.S. upper-level ridge are forecast to rise from Friday to Sunday, as a mid-level trough moves through the western U.S. An axis of maximized low-level moisture and instability is forecast to remain over the central and northern Plains extending south-southeastward into the mid Missouri Valley. Thunderstorm development, with a potential severe threat, will be possible across parts of this unstable airmass each afternoon and evening. Subsidence associated with the upper-level ridge will be a negative factor, which is expected to keep the severe threat isolated and marginal through the weekend. ...Monday/Day 7 and Tuesday/Day 8... The medium-range models are finally in agreement concerning the timing of an upper-level trough, which is forecast to move through the northern Plains on Monday. Ahead of this trough, a moist and unstable airmass is forecast from the mid Missouri Valley northeastward into the western Great Lakes. Thunderstorms are expected to develop ahead of the trough over parts of the Minnesota and Wisconsin, with more isolated convection southward into Iowa. Strong instability and moderate deep-layer shear should be favorable for a severe threat, with the most likely area in the upper Mississippi Valley Monday afternoon and evening. However, there is still uncertainty concerning the timing of the trough, and location of the instability axis on Monday. In addition, part of the airmass could remain capped. At this point, will not outlook a threat area. The potential severe threat is forecast to shift eastward into the central Great Lakes region on Tuesday, but could be isolated due to the presence of a northeastern U.S. upper-level ridge. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0338 AM CDT Tue Aug 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... Heights within the persistent central U.S. upper-level ridge are forecast to rise from Friday to Sunday, as a mid-level trough moves through the western U.S. An axis of maximized low-level moisture and instability is forecast to remain over the central and northern Plains extending south-southeastward into the mid Missouri Valley. Thunderstorm development, with a potential severe threat, will be possible across parts of this unstable airmass each afternoon and evening. Subsidence associated with the upper-level ridge will be a negative factor, which is expected to keep the severe threat isolated and marginal through the weekend. ...Monday/Day 7 and Tuesday/Day 8... The medium-range models are finally in agreement concerning the timing of an upper-level trough, which is forecast to move through the northern Plains on Monday. Ahead of this trough, a moist and unstable airmass is forecast from the mid Missouri Valley northeastward into the western Great Lakes. Thunderstorms are expected to develop ahead of the trough over parts of the Minnesota and Wisconsin, with more isolated convection southward into Iowa. Strong instability and moderate deep-layer shear should be favorable for a severe threat, with the most likely area in the upper Mississippi Valley Monday afternoon and evening. However, there is still uncertainty concerning the timing of the trough, and location of the instability axis on Monday. In addition, part of the airmass could remain capped. At this point, will not outlook a threat area. The potential severe threat is forecast to shift eastward into the central Great Lakes region on Tuesday, but could be isolated due to the presence of a northeastern U.S. upper-level ridge. Read more

Issued at 200 AM PDT Tue Aug 20 2024 000 WTPZ42 KNHC 200840 TCDEP2 Tropical Storm Gilma Discussion Number 8 NWS National Hurricane Center Miami FL EP072024 200 AM PDT Tue Aug 20 2024 Gilma continues to struggle with moderate to strong northeasterly vertical wind shear. The center is exposed more than 30 n mi to the northeast of the main convective overcast area. A 20/0129 UTC SSMIS pass and a pair of more recent ASCAT passes were helpful in placing the center well outside of the convective area. The highest reliable ASCAT vectors were only about 40 kt. UW-CIMSS objective intensity estimates range from 34-42 kt. Subjective current intensity estimates from TAFB and SAB were T-3.5/55 kt and T-3.0/45 kt from SAB. Based on the degraded structure on satellite imagery, the ASCAT data and the objective intensity estimates from UW-CIMSS, the initial intensity is set to 45 kt for this advisory. The aforementioned microwave and ASCAT data indicate that the center of the cyclone is a bit farther north than previously estimated. It appears that Gilma has slowed down, and the motion is estimated to be west-northwestward, or 295/7 kt. A mid-level ridge to the north of Gilma should steer the cyclone generally west-northwestward at a similar forward speed through the forecast period. Although the track guidance is gradually coming into better agreement, there is still more spread than normal among the various track aids. The official track forecast is quite similar to the previous NHC track prediction. The NHC forecast track is closer to the ECMWF model than the GFS model through 72 h, and is close to an average of those two models beyond 72 h. Moderate to strong northeasterly vertical wind shear will continue to affect Gilma for another 12 h or so. The SHIPS guidance indicates that the cyclone will reach a much lower wind shear regime by 24 h. Therefore, little change in strength is expected during the next 12-24 h, following by steady intensification. The official intensity forecast was lowered in the short term due to the weaker initial intensity. However, the guidance has become more aggressive after the cyclone reaches the weaker shear, and the NHC forecast follows suit, now showing a peak of 85 kt in 60-72 hr. The new NHC intensity forecast is near the middle of the guidance envelope, in between the weaker statistical guidance and the stronger regional hurricane model dynamical guidance. SSTs along Gilma's path should decrease to about 26C in 72 h, and remain at that value through 96 h before dropping to below 26C. Weakening is forecast during that time period. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 15.7N 118.3W 45 KT 50 MPH 12H 20/1800Z 16.0N 119.8W 45 KT 50 MPH 24H 21/0600Z 16.4N 121.5W 50 KT 60 MPH 36H 21/1800Z 16.8N 123.0W 60 KT 70 MPH 48H 22/0600Z 17.3N 124.2W 70 KT 80 MPH 60H 22/1800Z 17.7N 125.3W 85 KT 100 MPH 72H 23/0600Z 18.2N 126.4W 85 KT 100 MPH 96H 24/0600Z 19.0N 128.6W 75 KT 85 MPH 120H 25/0600Z 20.0N 131.2W 60 KT 70 MPH $$ Forecaster Hagen/Pasch

Issued at 0900 UTC TUE AUG 20 2024 000 FOPZ12 KNHC 200838 PWSEP2 TROPICAL STORM GILMA WIND SPEED PROBABILITIES NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 0900 UTC TUE AUG 20 2024 AT 0900Z THE CENTER OF TROPICAL STORM GILMA WAS LOCATED NEAR LATITUDE 15.7 NORTH...LONGITUDE 118.3 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 45 KTS...50 MPH...85 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 06Z TUE 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 06Z TUE 18Z TUE 06Z WED 18Z WED 06Z THU 06Z FRI 06Z SAT PERIODS TO TO TO TO TO TO TO 18Z TUE 06Z WED 18Z WED 06Z THU 06Z FRI 06Z SAT 06Z SUN FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 15N 120W 34 64 3(67) 1(68) 1(69) X(69) X(69) X(69) 20N 120W 34 X 2( 2) 2( 4) 2( 6) 1( 7) X( 7) X( 7) 15N 125W 34 X 2( 2) 8(10) 10(20) 8(28) 2(30) X(30) 20N 125W 34 X 1( 1) 3( 4) 11(15) 30(45) 5(50) 1(51) 20N 125W 50 X X( X) X( X) 1( 1) 9(10) 2(12) X(12) 20N 125W 64 X X( X) X( X) X( X) 3( 3) 1( 4) X( 4) 15N 130W 34 X X( X) X( X) X( X) 3( 3) 4( 7) 2( 9) 20N 130W 34 X X( X) X( X) X( X) 9( 9) 33(42) 17(59) 20N 130W 50 X X( X) X( X) X( X) 1( 1) 11(12) 13(25) 20N 130W 64 X X( X) X( X) X( X) X( X) 6( 6) 5(11) 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) 1( 1) 7( 8) $$ FORECASTER HAGEN/PASCH

Issued at 200 AM PDT Tue Aug 20 2024 000 WTPZ32 KNHC 200838 TCPEP2 BULLETIN Tropical Storm Gilma Advisory Number 8 NWS National Hurricane Center Miami FL EP072024 200 AM PDT Tue Aug 20 2024 ...GILMA CONTINUES TO BATTLE STRONG WIND SHEAR... SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...15.7N 118.3W ABOUT 740 MI...1190 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 8 MPH...13 KM/H MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 200 AM PDT (0900 UTC), the center of Tropical Storm Gilma was located near latitude 15.7 North, longitude 118.3 West. Gilma is moving toward the west-northwest near 8 mph (13 km/h) and this general motion is expected to continue during the next few days. Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Little change in strength is expected today. Steady strengthening is expected to resume tonight, and Gilma is forecast to become a hurricane by Thursday. Tropical-storm-force winds extend outward up to 115 miles (185 km) from the center. The estimated minimum central pressure is 1000 mb (29.53 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 800 AM PDT. $$ Forecaster Hagen/Pasch

...GILMA CONTINUES TO BATTLE STRONG WIND SHEAR... As of 2:00 AM PDT Tue Aug 20 the center of Gilma was located near 15.7, -118.3 with movement WNW at 8 mph. The minimum central pressure was 1000 mb with maximum sustained winds of about 50 mph.

Issued at 0900 UTC TUE AUG 20 2024 940 WTPZ22 KNHC 200838 TCMEP2 TROPICAL STORM GILMA FORECAST/ADVISORY NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 0900 UTC TUE AUG 20 2024 TROPICAL STORM CENTER LOCATED NEAR 15.7N 118.3W AT 20/0900Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 7 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1000 MB MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. 34 KT....... 40NE 90SE 100SW 60NW. 12 FT SEAS.. 60NE 60SE 60SW 60NW. 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 15.7N 118.3W AT 20/0900Z AT 20/0600Z CENTER WAS LOCATED NEAR 15.6N 117.8W FORECAST VALID 20/1800Z 16.0N 119.8W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 50NE 100SE 100SW 70NW. FORECAST VALID 21/0600Z 16.4N 121.5W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 30NE 30SE 30SW 0NW. 34 KT... 60NE 110SE 110SW 70NW. FORECAST VALID 21/1800Z 16.8N 123.0W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 40SE 40SW 30NW. 34 KT... 70NE 110SE 110SW 70NW. FORECAST VALID 22/0600Z 17.3N 124.2W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 20NE 20SE 0SW 20NW. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 80NE 100SE 100SW 80NW. FORECAST VALID 22/1800Z 17.7N 125.3W MAX WIND 85 KT...GUSTS 105 KT. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 90NE 90SE 80SW 90NW. FORECAST VALID 23/0600Z 18.2N 126.4W MAX WIND 85 KT...GUSTS 105 KT. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 90NE 80SE 80SW 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 24/0600Z 19.0N 128.6W MAX WIND 75 KT...GUSTS 90 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT... 90NE 80SE 80SW 100NW. OUTLOOK VALID 25/0600Z 20.0N 131.2W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 50NE 40SE 30SW 40NW. 34 KT...100NE 80SE 70SW 100NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.7N 118.3W NEXT ADVISORY AT 20/1500Z $$ FORECASTER HAGEN/PASCH

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Tue Aug 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Thunderstorms with hail and a few marginally severe gusts will be possible on Thursday across parts of the central and northern Plains. ...Central and Northern Plains... An upper-level ridge is forecast to move eastward across the central and northern Plains on Thursday. To the west of the ridge, an axis of instability is forecast to be in place from western Kansas northward into east-central North Dakota. Near this axis, surface dewpoints in the mid to upper 60s F will contribute to the development of moderate instability by afternoon. In addition to the instability, 0-6 km shear is forecast to be in the 25 to 35 knot range along much of this corridor, which should be sufficient for an isolated severe threat. As surface temperatures warm during the day, any cell that can initiate near the instability axis could have potential for hail and severe gusts. There is some uncertainty concerning Thursday's forecast. First, the models vary considerably on the distribution and magnitude of instability. Second, the models differ significantly on convective coverage. The current thinking is that storm coverage will remain relatively isolated due to subsidence in the wake of the ridge, and that convection may tend to develop further to the east away from the instability axis. For this reason, a marginal risk should be sufficient for this forecast. ..Broyles.. 08/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Tue Aug 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Thunderstorms with hail and a few marginally severe gusts will be possible on Thursday across parts of the central and northern Plains. ...Central and Northern Plains... An upper-level ridge is forecast to move eastward across the central and northern Plains on Thursday. To the west of the ridge, an axis of instability is forecast to be in place from western Kansas northward into east-central North Dakota. Near this axis, surface dewpoints in the mid to upper 60s F will contribute to the development of moderate instability by afternoon. In addition to the instability, 0-6 km shear is forecast to be in the 25 to 35 knot range along much of this corridor, which should be sufficient for an isolated severe threat. As surface temperatures warm during the day, any cell that can initiate near the instability axis could have potential for hail and severe gusts. There is some uncertainty concerning Thursday's forecast. First, the models vary considerably on the distribution and magnitude of instability. Second, the models differ significantly on convective coverage. The current thinking is that storm coverage will remain relatively isolated due to subsidence in the wake of the ridge, and that convection may tend to develop further to the east away from the instability axis. For this reason, a marginal risk should be sufficient for this forecast. ..Broyles.. 08/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Tue Aug 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Thunderstorms with hail and a few marginally severe gusts will be possible on Thursday across parts of the central and northern Plains. ...Central and Northern Plains... An upper-level ridge is forecast to move eastward across the central and northern Plains on Thursday. To the west of the ridge, an axis of instability is forecast to be in place from western Kansas northward into east-central North Dakota. Near this axis, surface dewpoints in the mid to upper 60s F will contribute to the development of moderate instability by afternoon. In addition to the instability, 0-6 km shear is forecast to be in the 25 to 35 knot range along much of this corridor, which should be sufficient for an isolated severe threat. As surface temperatures warm during the day, any cell that can initiate near the instability axis could have potential for hail and severe gusts. There is some uncertainty concerning Thursday's forecast. First, the models vary considerably on the distribution and magnitude of instability. Second, the models differ significantly on convective coverage. The current thinking is that storm coverage will remain relatively isolated due to subsidence in the wake of the ridge, and that convection may tend to develop further to the east away from the instability axis. For this reason, a marginal risk should be sufficient for this forecast. ..Broyles.. 08/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Tue Aug 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Thunderstorms with hail and a few marginally severe gusts will be possible on Thursday across parts of the central and northern Plains. ...Central and Northern Plains... An upper-level ridge is forecast to move eastward across the central and northern Plains on Thursday. To the west of the ridge, an axis of instability is forecast to be in place from western Kansas northward into east-central North Dakota. Near this axis, surface dewpoints in the mid to upper 60s F will contribute to the development of moderate instability by afternoon. In addition to the instability, 0-6 km shear is forecast to be in the 25 to 35 knot range along much of this corridor, which should be sufficient for an isolated severe threat. As surface temperatures warm during the day, any cell that can initiate near the instability axis could have potential for hail and severe gusts. There is some uncertainty concerning Thursday's forecast. First, the models vary considerably on the distribution and magnitude of instability. Second, the models differ significantly on convective coverage. The current thinking is that storm coverage will remain relatively isolated due to subsidence in the wake of the ridge, and that convection may tend to develop further to the east away from the instability axis. For this reason, a marginal risk should be sufficient for this forecast. ..Broyles.. 08/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Tue Aug 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Thunderstorms with hail and a few marginally severe gusts will be possible on Thursday across parts of the central and northern Plains. ...Central and Northern Plains... An upper-level ridge is forecast to move eastward across the central and northern Plains on Thursday. To the west of the ridge, an axis of instability is forecast to be in place from western Kansas northward into east-central North Dakota. Near this axis, surface dewpoints in the mid to upper 60s F will contribute to the development of moderate instability by afternoon. In addition to the instability, 0-6 km shear is forecast to be in the 25 to 35 knot range along much of this corridor, which should be sufficient for an isolated severe threat. As surface temperatures warm during the day, any cell that can initiate near the instability axis could have potential for hail and severe gusts. There is some uncertainty concerning Thursday's forecast. First, the models vary considerably on the distribution and magnitude of instability. Second, the models differ significantly on convective coverage. The current thinking is that storm coverage will remain relatively isolated due to subsidence in the wake of the ridge, and that convection may tend to develop further to the east away from the instability axis. For this reason, a marginal risk should be sufficient for this forecast. ..Broyles.. 08/20/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0143 AM CDT Tue Aug 20 2024 Valid 211200Z - 221200Z ...Synopsis... Broad southwesterly mid-level flow, and a progressive shortwave trough moving through the northern Great Basin/Northwest U.S., will bring sustained dry/windy conditions to portions of Nevada, Utah, and Idaho on Wednesday. ...Dry/Windy... Deep boundary-layer mixing beneath broad southwesterly mid-level flow, and a progressive shortwave trough moving from northern Nevada/southern Oregon into Idaho and Montana, will be responsible for elevated fire-weather conditions across the Great Basin on Wednesday. High-resolution ensemble guidance suggests there may be a narrow corridor of critical fire-weather conditions across Nevada, where relative humidity values will drop into the single digits and winds could get as high as 20-25 MPH. This area currently overlaps with fuels that are not expected to be receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles. However, with dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and critical highlights could be needed in subsequent updates. ...Dry Thunderstorms... A mix of wet and dry thunderstorms will be possible across southwestern Montana, with additional dry thunderstorm development likely across southern Colorado and northern New Mexico. However, current fuels guidance suggests that both of these regions are unlikely to be receptive to new ignitions and wildfire spread, with ERC values below the 60th annual percentile for both regions. ..Halbert/Squitieri.. 08/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0143 AM CDT Tue Aug 20 2024 Valid 211200Z - 221200Z ...Synopsis... Broad southwesterly mid-level flow, and a progressive shortwave trough moving through the northern Great Basin/Northwest U.S., will bring sustained dry/windy conditions to portions of Nevada, Utah, and Idaho on Wednesday. ...Dry/Windy... Deep boundary-layer mixing beneath broad southwesterly mid-level flow, and a progressive shortwave trough moving from northern Nevada/southern Oregon into Idaho and Montana, will be responsible for elevated fire-weather conditions across the Great Basin on Wednesday. High-resolution ensemble guidance suggests there may be a narrow corridor of critical fire-weather conditions across Nevada, where relative humidity values will drop into the single digits and winds could get as high as 20-25 MPH. This area currently overlaps with fuels that are not expected to be receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles. However, with dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and critical highlights could be needed in subsequent updates. ...Dry Thunderstorms... A mix of wet and dry thunderstorms will be possible across southwestern Montana, with additional dry thunderstorm development likely across southern Colorado and northern New Mexico. However, current fuels guidance suggests that both of these regions are unlikely to be receptive to new ignitions and wildfire spread, with ERC values below the 60th annual percentile for both regions. ..Halbert/Squitieri.. 08/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0143 AM CDT Tue Aug 20 2024 Valid 211200Z - 221200Z ...Synopsis... Broad southwesterly mid-level flow, and a progressive shortwave trough moving through the northern Great Basin/Northwest U.S., will bring sustained dry/windy conditions to portions of Nevada, Utah, and Idaho on Wednesday. ...Dry/Windy... Deep boundary-layer mixing beneath broad southwesterly mid-level flow, and a progressive shortwave trough moving from northern Nevada/southern Oregon into Idaho and Montana, will be responsible for elevated fire-weather conditions across the Great Basin on Wednesday. High-resolution ensemble guidance suggests there may be a narrow corridor of critical fire-weather conditions across Nevada, where relative humidity values will drop into the single digits and winds could get as high as 20-25 MPH. This area currently overlaps with fuels that are not expected to be receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles. However, with dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and critical highlights could be needed in subsequent updates. ...Dry Thunderstorms... A mix of wet and dry thunderstorms will be possible across southwestern Montana, with additional dry thunderstorm development likely across southern Colorado and northern New Mexico. However, current fuels guidance suggests that both of these regions are unlikely to be receptive to new ignitions and wildfire spread, with ERC values below the 60th annual percentile for both regions. ..Halbert/Squitieri.. 08/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more