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5-Day Uncertainty Track last updated Tue, 27 Aug 2024 20:35:46 GMT


Wind Speed Probabilities last updated Tue, 27 Aug 2024 21:34:44 GMT

Issued at 2100 UTC TUE AUG 27 2024 386 FOPZ13 KNHC 272035 PWSEP3 TROPICAL STORM HECTOR WIND SPEED PROBABILITIES NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082024 2100 UTC TUE AUG 27 2024 AT 2100Z THE CENTER OF TROPICAL STORM HECTOR WAS LOCATED NEAR LATITUDE 17.8 NORTH...LONGITUDE 129.8 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 18Z 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 18Z TUE 06Z WED 18Z WED 06Z THU 18Z THU 18Z FRI 18Z SAT PERIODS TO TO TO TO TO TO TO 06Z WED 18Z WED 06Z THU 18Z THU 18Z FRI 18Z SAT 18Z SUN FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 20N 135W 34 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) 20N 140W 34 X X( X) X( X) 1( 1) 3( 4) X( 4) X( 4) $$ FORECASTER LANDSEA

Issued at 1100 AM HST Tue Aug 27 2024 000 WTPZ33 KNHC 272034 TCPEP3 BULLETIN Tropical Storm Hector Advisory Number 9 NWS National Hurricane Center Miami FL EP082024 1100 AM HST Tue Aug 27 2024 ...HECTOR STRENGTHENS SLIGHTLY OVER THE OPEN PACIFIC... SUMMARY OF 1100 AM HST...2100 UTC...INFORMATION ----------------------------------------------- LOCATION...17.8N 129.8W ABOUT 1335 MI...2145 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 1100 AM HST (2100 UTC), the center of Tropical Storm Hector was located near latitude 17.8 North, longitude 129.8 West. Hector is moving toward the west-northwest near 12 mph (19 km/h). The system is expected to turn on Wednesday toward the west at a similar forward speed. Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Some weakening is forecast during the next 48 hours and it is anticipated that Hector will weaken to a tropical depression by Wednesday night. Tropical-storm-force winds extend outward up to 70 miles (110 km) from the center. The estimated minimum central pressure is 1001 mb (29.56 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 500 PM HST. $$ Forecaster Landsea

...HECTOR STRENGTHENS SLIGHTLY OVER THE OPEN PACIFIC... As of 11:00 AM HST Tue Aug 27 the center of Hector was located near 17.8, -129.8 with movement WNW at 12 mph. The minimum central pressure was 1001 mb with maximum sustained winds of about 50 mph.

Issued at 2100 UTC TUE AUG 27 2024 000 WTPZ23 KNHC 272033 TCMEP3 TROPICAL STORM HECTOR FORECAST/ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082024 2100 UTC TUE AUG 27 2024 TROPICAL STORM CENTER LOCATED NEAR 17.8N 129.8W AT 27/2100Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1001 MB MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. 34 KT....... 60NE 0SE 0SW 60NW. 12 FT SEAS..120NE 60SE 60SW 90NW. 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 17.8N 129.8W AT 27/2100Z AT 27/1800Z CENTER WAS LOCATED NEAR 17.7N 129.3W FORECAST VALID 28/0600Z 18.1N 131.5W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 60NE 0SE 0SW 30NW. FORECAST VALID 28/1800Z 18.3N 133.5W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 60NE 0SE 0SW 40NW. FORECAST VALID 29/0600Z 18.4N 135.7W MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 29/1800Z 18.4N 138.1W...POST-TROP/REMNT LOW MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 30/0600Z 18.3N 141.0W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 30/1800Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 17.8N 129.8W NEXT ADVISORY AT 28/0300Z $$ FORECASTER LANDSEA

WW 0656 Status Updates
STATUS REPORT ON WW 656 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 W BEH TO 25 NE BEH TO 20 SSW GRR TO 35 NNW LAN TO 35 WSW MBS TO 25 NW MBS TO 20 SE HTL TO 35 NNE HTL. ..JEWELL..08/27/24 ATTN...WFO...GRR...APX... STATUS REPORT FOR WS 656 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC005-011-015-025-037-045-051-057-065-067-069-075-077-117-129- 159-272140- MI . MICHIGAN COUNTIES INCLUDED ARE ALLEGAN ARENAC BARRY CALHOUN CLINTON EATON GLADWIN GRATIOT INGHAM IONIA IOSCO JACKSON KALAMAZOO MONTCALM OGEMAW VAN BUREN LHZ363-272140- CW . ADJACENT COASTAL WATERS INCLUDED ARE LAKE HURON FROM STURGEON POINT TO ALABASTER MI 5NM OFF SHORE TO US/CANADIAN BORDER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE Read more

MD 2014 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL/EASTERN KANSAS
Mesoscale Discussion 2014 NWS Storm Prediction Center Norman OK 0202 PM CDT Tue Aug 27 2024 Areas affected...Portions of central/eastern Kansas Concerning...Severe potential...Watch unlikely Valid 271902Z - 272030Z Probability of Watch Issuance...5 percent SUMMARY...Isolated strong/marginally severe winds and small hail are possible this afternoon in central/eastern Kansas. A watch is not likely. DISCUSSION...A few thunderstorms have initiated along an outflow boundary in central Kansas. Additional storms are possible farther east as heating continues this afternoon. Though deep-layer shear is weak, 1500-2000 J/kg MLCAPE will support isolated strong/marginally severe downburst winds as storms collapse. Small hail could occur as well, but warm temperatures in the profile and the mentioned weak shear should limit potential for marginally severe hail. Storms should have a tendency to move northward given the location of the upper-level ridge where continuing modification of the outflow should eventually support strong wind gusts. ..Wendt/Guyer.. 08/27/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SGF...EAX...TOP...ICT...GID...DDC... LAT...LON 37939636 38149732 38239796 38089859 38099937 38299956 39029929 39149917 39369903 39539704 39099527 38469462 37819478 37939636 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Aug 27 2024 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms capable of damaging thunderstorm winds and occasional large hail and a tornado or two are possible across the Great Lakes region and portions of the Midwest through tonight. ...20z Update... The prior forecast remains largely on track with minor changes. The Slight and Marginal risk area over parts of WI was trimmed behind extensive convection ongoing over the Lake and northern MI. Ongoing severe storms over parts of the Great Lakes are expected to gradually expand in coverage and intensity over southern lower MI, northern IL and IN through the remainder of the afternoon and into the evening/overnight. The primary risk remains damaging winds associated with organized clusters or bowing segments, but hail and a tornado or two will also remain possible. Farther south into parts of the Mississippi Valley and eastern Plains, additional storm development/intensification is probable this afternoon within a warm and unstable air mass ahead of a weak cold front. Vertical shear is somewhat weaker displaced south of the main shortwave trough, but robust boundary-layer heating should suffice for periodic intensification of multicell storms. At least some damaging wind or hail risk may develop with clusters of strong to severe storms across eastern KS and south-central IA from this afternoon through the evening. ..Lyons.. 08/27/2024 .PREV DISCUSSION... /ISSUED 1142 AM CDT Tue Aug 27 2024/ ...Great Lakes/Midwest/Central Plains... A rather complex mesoscale scenario exists particularly across the Great Lakes region, influenced by multiple MCSs/outflows since last evening. Multiple MCVs are apparent across the region including western Upper Michigan, potentially including an MCV with evolving asymmetric quasi-linear convection across east-central Wisconsin late this morning. Within a zone of pre-frontal confluence/augmented outflow, MCS persistence and further upscale/southward peripheral growth is possible into Lower Michigan/northern Illinois into a very unstable air mass, but this is far from certain. For additional short-term information, see Mesoscale Discussion 2013. Where storm clusters do develop and intensify regionally, ample buoyancy, particularly south of the aforementioned late-morning MCS, and sufficient deep-layer shear will support damaging wind and isolated large hail potential. The severe threat could reach as far as the Lake Ontario vicinity late tonight/early Wednesday. Farther southwest, nearer to the cold front and potentially augmented by residual outflow, CAPE and especially vertical shear will be weaker from southeast Iowa/western Illinois into northern Missouri and eastern Kansas/southeast Nebraska. A few organized multicells are possible atop a strongly heated boundary layer, with strong wind gusts and severe hail possible. Read more