Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1220 AM CDT Thu Sep 26 2024 Valid 261200Z - 271200Z ...Synopsis... The pattern across the US on Thursday will be characterized by Hurricane Helene moving inland and becoming absorbed into the upper-level flow across the eastern US as a ridge of high pressure continues to be in place across the western US. Across the northern Rockies, a shortwave trough will traverse the northern periphery of the ridge with a dry cold front sagging southward into the northern Plains through the period. Ahead of the front, relative humidity around 15-20 percent will be possible across portions of eastern Wyoming into South Dakota. The frontal passage will bring an increase in surface winds, with sustained winds around 20-25 mph. There is some question as to what the duration of overlap will be between the lower relative humidity and stronger wind speeds. HREF probabilities of Elevated to Critical conditions remain generally around 30-40 percent. Fuels across much of eastern Wyoming into South Dakota are critically dry. Taking into account the possibility of briefly Elevated to locally Critical conditions, an Elevated area was included with this outlook given the uncertainty. ..Thornton.. 09/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

Issued at 900 PM CST Wed Sep 25 2024 000 WTPZ45 KNHC 260335 CCA TCDEP5 Tropical Storm John Discussion Number 13...Corrected NWS National Hurricane Center Miami FL EP102024 900 PM CST Wed Sep 25 2024 Corrected Hurricane to Tropical Storm John An Air Force Reserve Hurricane Hunter Aircraft just finished its investigation of Tropical Storm John and found that the central pressure has dropped to 984 mb. Dropsonde data and SFMR data support an intensity of 55 kt, which is also the average of the latest TAFB and SAB intensity estimates. Satellite imagery shows a very large area of very cold cloud tops. Based on the available data, the initial intensity is increased to 55 kt. Based on fixes from the Air Force plane, the initial motion is estimated to be northwestward, or 325/4 kt. The model guidance has made a big shift to the west on this cycle, which makes sense since John has been moving significantly to the west of the previous NHC forecast track. The new NHC track forecast has been shifted well to the west, and currently lies slightly to the east of the latest track consensus aids. The westward shift to the track has necessitated the Hurricane Warnings to be shifted farther west along the coast of Mexico. The new forecast shows landfall occurring about 40 to 50 miles farther to the west compared to the previous official forecast, with the forecast landfall now well to the west of Lazaro Cardenas later Thursday night. It should be noted that there is still quite a bit of uncertainty in the track forecast. Tropical Storm John is currently located over 31C sea-surface temperatures, which is extremely warm. The tropical storm is also in a moist environment and appears to also have a favorable upper-level wind environment. Both the GFS-SHIPS and the ECMWF-SHIPS Rapid-Intensity-Index shows a very high chance of rapid intensification over the next 24 hours. The new NHC intensity forecast has been increased significantly from the previous official forecast, and lies near the high end of the latest intensity guidance suite. Given the extremely favorable environmental conditions, it wouldn't be surprising if further increases to the intensity forecast are needed on subsequent forecasts. Although this forecast shows dissipation by hour 60, there is a chance that John could survive a bit longer, moving west-northwestward near the coast of Mexico. It cannot be emphasized enough that catastrophic life-threatening flash flooding and mudslides are expected to continue through the end of the week for portions of the Mexican States of Guerrero, Oaxaca and Michoacan. KEY MESSAGES: 1. Tropical Storm John will bring additional very heavy rainfall to coastal portions of southwest Mexico through Friday. The additional rainfall totals will be falling across areas that have received very heavy rainfall amounts over the past few days. This heavy rainfall will likely cause significant and catastrophic life-threatening flash flooding and mudslides to the Mexican States of Guerrero, Oaxaca and Michoacan. 2. John is forecast to strengthen to a hurricane before landfall, and the Hurricane Warning has been extended westward along the coastline of southwestern Mexico, where tropical storm conditions could begin within the next few hours. Tropical Storm Warnings are also in effect for portions of the area. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 17.0N 102.1W 55 KT 65 MPH 12H 26/1200Z 17.3N 102.3W 65 KT 75 MPH 24H 27/0000Z 17.7N 102.5W 80 KT 90 MPH 36H 27/1200Z 18.1N 102.7W 70 KT 80 MPH...INLAND 48H 28/0000Z 18.4N 103.2W 30 KT 35 MPH...INLAND 60H 28/1200Z...DISSIPATED $$ Forecaster Hagen

5-Day Uncertainty Track last updated Thu, 26 Sep 2024 02:36:06 GMT


Wind Speed Probabilities last updated Thu, 26 Sep 2024 03:35:02 GMT

Issued at 900 PM CST Wed Sep 25 2024 000 WTPZ45 KNHC 260235 TCDEP5 Tropical Storm John Discussion Number 13 NWS National Hurricane Center Miami FL EP102024 900 PM CST Wed Sep 25 2024 An Air Force Reserve Hurricane Hunter Aircraft just finished its investigation of Hurricane John and found that the central pressure has dropped to 984 mb. Dropsonde data and SFMR data support an intensity of 55 kt, which is also the average of the latest TAFB and SAB intensity estimates. Satellite imagery shows a very large area of very cold cloud tops. Based on the available data, the initial intensity is increased to 55 kt. Based on fixes from the Air Force plane, the initial motion is estimated to be northwestward, or 325/4 kt. The model guidance has made a big shift to the west on this cycle, which makes sense since John has been moving significantly to the west of the previous NHC forecast track. The new NHC track forecast has been shifted well to the west, and currently lies slightly to the east of the latest track consensus aids. The westward shift to the track has necessitated the Hurricane Warnings to be shifted farther west along the coast of Mexico. The new forecast shows landfall occurring about 40 to 50 miles farther to the west compared to the previous official forecast, with the forecast landfall now well to the west of Lazaro Cardenas later Thursday night. It should be noted that there is still quite a bit of uncertainty in the track forecast. Hurricane John is currently located over 31C sea-surface temperatures, which is extremely warm. The hurricane is also in a moist environment and appears to also have a favorable upper-level wind environment. Both the GFS-SHIPS and the ECMWF-SHIPS Rapid-Intensity-Index shows a very high chance of rapid intensification over the next 24 hours. The new NHC intensity forecast has been increased significantly from the previous official forecast, and lies near the high end of the latest intensity guidance suite. Given the extremely favorable environmental conditions, it wouldn't be surprising if further increases to the intensity forecast are needed on subsequent forecasts. Although this forecast shows dissipation by hour 60, there is a chance that John could survive a bit longer, moving west-northwestward near the coast of Mexico. It cannot be emphasized enough that catastrophic life-threatening flash flooding and mudslides are expected to continue through the end of the week for portions of the Mexican States of Guerrero, Oaxaca and Michoacan. KEY MESSAGES: 1. Tropical Storm John will bring additional very heavy rainfall to coastal portions of southwest Mexico through Friday. The additional rainfall totals will be falling across areas that have received very heavy rainfall amounts over the past few days. This heavy rainfall will likely cause significant and catastrophic life-threatening flash flooding and mudslides to the Mexican States of Guerrero, Oaxaca and Michoacan. 2. John is forecast to strengthen to a hurricane before landfall, and the Hurricane Warning has been extended westward along the coastline of southwestern Mexico, where tropical storm conditions could begin within the next few hours. Tropical Storm Warnings are also in effect for portions of the area. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 17.0N 102.1W 55 KT 65 MPH 12H 26/1200Z 17.3N 102.3W 65 KT 75 MPH 24H 27/0000Z 17.7N 102.5W 80 KT 90 MPH 36H 27/1200Z 18.1N 102.7W 70 KT 80 MPH...INLAND 48H 28/0000Z 18.4N 103.2W 30 KT 35 MPH...INLAND 60H 28/1200Z...DISSIPATED $$ Forecaster Hagen

Issued at 0300 UTC THU SEP 26 2024 000 FOPZ15 KNHC 260234 PWSEP5 TROPICAL STORM JOHN WIND SPEED PROBABILITIES NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102024 0300 UTC THU SEP 26 2024 AT 0300Z THE CENTER OF TROPICAL STORM JOHN WAS LOCATED NEAR LATITUDE 17.0 NORTH...LONGITUDE 102.1 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 00Z 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 00Z THU 12Z THU 00Z FRI 12Z FRI 00Z SAT 00Z SUN 00Z MON PERIODS TO TO TO TO TO TO TO 12Z THU 00Z FRI 12Z FRI 00Z SAT 00Z SUN 00Z MON 00Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 15N 105W 34 2 2( 4) 2( 6) X( 6) X( 6) X( 6) X( 6) BARRA NAVIDAD 34 X 1( 1) 1( 2) 3( 5) X( 5) X( 5) X( 5) MANZANILLO 34 2 8(10) 6(16) 9(25) X(25) X(25) X(25) MANZANILLO 50 X X( X) 1( 1) 3( 4) X( 4) X( 4) X( 4) MANZANILLO 64 X X( X) X( X) 1( 1) X( 1) X( 1) X( 1) L CARDENAS 34 79 15(94) 2(96) X(96) X(96) X(96) X(96) L CARDENAS 50 9 31(40) 6(46) 1(47) X(47) X(47) X(47) L CARDENAS 64 2 12(14) 4(18) 1(19) X(19) X(19) X(19) ZIHUATANEJO 34 76 15(91) 1(92) 1(93) X(93) X(93) X(93) ZIHUATANEJO 50 3 10(13) 1(14) 1(15) X(15) X(15) X(15) ZIHUATANEJO 64 1 2( 3) 1( 4) X( 4) X( 4) X( 4) X( 4) 15N 100W 34 2 4( 6) 1( 7) X( 7) X( 7) X( 7) X( 7) ACAPULCO 34 4 7(11) 2(13) X(13) X(13) X(13) X(13) P MALDONADO 34 2 2( 4) X( 4) X( 4) X( 4) X( 4) X( 4) $$ FORECASTER HAGEN

Issued at 0300 UTC THU SEP 26 2024 000 WTPZ25 KNHC 260234 TCMEP5 TROPICAL STORM JOHN FORECAST/ADVISORY NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102024 0300 UTC THU SEP 26 2024 TROPICAL STORM CENTER LOCATED NEAR 17.0N 102.1W AT 26/0300Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 325 DEGREES AT 4 KT ESTIMATED MINIMUM CENTRAL PRESSURE 984 MB MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. 50 KT....... 0NE 15SE 15SW 20NW. 34 KT....... 40NE 130SE 110SW 50NW. 12 FT SEAS.. 0NE 300SE 240SW 0NW. 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 17.0N 102.1W AT 26/0300Z AT 26/0000Z CENTER WAS LOCATED NEAR 16.9N 102.0W FORECAST VALID 26/1200Z 17.3N 102.3W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 10NE 10SE 10SW 10NW. 50 KT... 20NE 30SE 20SW 20NW. 34 KT... 50NE 150SE 130SW 60NW. FORECAST VALID 27/0000Z 17.7N 102.5W MAX WIND 80 KT...GUSTS 100 KT. 64 KT... 10NE 15SE 10SW 10NW. 50 KT... 20NE 30SE 30SW 20NW. 34 KT... 60NE 150SE 120SW 60NW. FORECAST VALID 27/1200Z 18.1N 102.7W...INLAND MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 0NE 10SE 10SW 0NW. 50 KT... 10NE 20SE 20SW 10NW. 34 KT... 30NE 90SE 60SW 30NW. FORECAST VALID 28/0000Z 18.4N 103.2W...INLAND MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 28/1200Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 17.0N 102.1W INTERMEDIATE PUBLIC ADVISORY...WTNT35 KNHC/MIATCPEP5...AT 26/0600Z NEXT ADVISORY AT 26/0900Z $$ FORECASTER HAGEN

Issued at 900 PM CST Wed Sep 25 2024 000 WTPZ35 KNHC 260234 TCPEP5 BULLETIN Tropical Storm John Advisory Number 13 NWS National Hurricane Center Miami FL EP102024 900 PM CST Wed Sep 25 2024 ...HURRICANE WARNING EXTENDED WESTWARD... ...THREAT OF CATASTROPHIC LIFE-THREATENING FLASH FLOODING AND MUDSLIDES CONTINUES OVER PORTIONS OF SOUTHERN MEXICO... SUMMARY OF 900 PM CST...0300 UTC...INFORMATION ---------------------------------------------- LOCATION...17.0N 102.1W ABOUT 70 MI...110 KM S OF LAZARO CARDENAS MEXICO ABOUT 60 MI...95 KM SW OF ZIHUATANEJO MEXICO MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...NW OR 325 DEGREES AT 5 MPH...7 KM/H MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of Mexico has issued a Hurricane Warning from Lazaro Cardenas to Punta San Telmo. The government of Mexico has canceled the Hurricane Watch from Acapulco to Tecpan de Galeana. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Tecpan de Galeana to Punta San Telmo A Tropical Storm Warning is in effect for... * Punta Maldonado to Tecpan de Galeana A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area, in this case within 24 to 36 hours. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 900 PM CST (0300 UTC), the center of Tropical Storm John was located near latitude 17.0 North, longitude 102.1 West. John is moving toward the northwest near 5 mph (7 km/h) and this motion is expected to continue for the next day or two, followed by a gradual turn to the west-northwest on Friday. On the forecast track, the center of John is forecast to approach the southwestern coast of Mexico on Thursday and be inland on Friday. Maximum sustained winds are near 65 mph (100 km/h) with higher gusts. John is forecast to strengthen to a hurricane by early Thursday, with additional strengthening expected until the center moves inland. Tropical-storm-force winds extend outward up to 150 miles (240 km) from the center. The estimated minimum central pressure is 984 mb (29.06 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Through Friday, Tropical Storm John is expected to produce additional rainfall amounts of 10 to 20 inches with isolated totals around 30 inches across portions of the Mexican States of Guerrero, Oaxaca and Michoacan. For a complete depiction of forecast rainfall associated with John, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep5.shtml?rainqpf STORM SURGE: A dangerous storm surge is expected to produce coastal flooding near and to the east of where the center makes landfall. Near the coast, the surge will be accompanied by large and destructive waves. WIND: Hurricane conditions are expected along the coast within the hurricane warning area by late Thursday or Thursday night. Winds are expected to first reach tropical storm strength within the next few hours, making outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. Tropical storm conditions are currently occurring over portions of the coast within the tropical storm warning area, and should continue into Thursday. SURF: Swells associated with John are forecast to continue to affect the coast of southern and southwestern Mexico through the week, with the potential for dangerous surf and rip currents. Please see local statements for more information. NEXT ADVISORY ------------- Next intermediate advisory at 1200 AM CST. Next complete advisory at 300 AM CST. $$ Forecaster Hagen

...HURRICANE WARNING EXTENDED WESTWARD... ...THREAT OF CATASTROPHIC LIFE-THREATENING FLASH FLOODING AND MUDSLIDES CONTINUES OVER PORTIONS OF SOUTHERN MEXICO... As of 9:00 PM CST Wed Sep 25 the center of John was located near 17.0, -102.1 with movement NW at 5 mph. The minimum central pressure was 984 mb with maximum sustained winds of about 65 mph.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Sep 25 2024 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN APPALACHIANS INTO PARTS OF THE SOUTHEAST AND FLORIDA... ...SUMMARY... Isolated strong to severe storms are possible this evening from the southern Appalachians into parts of the Southeast. Some tornado threat may develop later tonight over Florida, in association with Hurricane Helene. ...Florida... Hurricane Helene is forecast to intensify and move north to north-northeastward across the southeast Gulf of Mexico tonight; see NHC forecasts/advisories for more information. Helene's large wind field will continue to overspread the Florida Peninsula and Keys tonight, with low-level shear/SRH becoming increasingly favorable for low-topped supercells with a potential tornado threat. Low-topped supercell potential prior to 12Z Thursday morning remains uncertain, with inland instability expected to remain relatively limited. Outer rain bands could begin to affect the western Peninsula later tonight, while convection may persist near a convergence zone near the east coast. ...Southern Appalachians vicinity into parts of the Southeast... Widespread precipitation is ongoing this evening within a corridor from the FL Panhandle into western NC/VA, but weak to locally moderate buoyancy persists east of this band, with regional VWPs and the 00Z RNK sounding depicting vertically veering wind profiles favorable for organized convection. Generally weak low/midlevel lapse rates will tend to limit storm intensity, but marginal supercell potential may persist through the evening, with a threat of isolated damaging gusts and possibly a tornado. ...Northern ID/northeast WA/northwest MT... While low-level moisture is limited, steep lapse rates and ascent attendant to an approaching mid/upper-level shortwave trough are supporting a high-based storm cluster currently moving across the ID Panhandle. This cluster has a history of 60-65 mph gusts, and will move across northwest MT early this evening, with a continued threat of strong to locally severe gusts. ..Dean.. 09/26/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Sep 25 2024 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN APPALACHIANS INTO PARTS OF THE SOUTHEAST AND FLORIDA... ...SUMMARY... Isolated strong to severe storms are possible this evening from the southern Appalachians into parts of the Southeast. Some tornado threat may develop later tonight over Florida, in association with Hurricane Helene. ...Florida... Hurricane Helene is forecast to intensify and move north to north-northeastward across the southeast Gulf of Mexico tonight; see NHC forecasts/advisories for more information. Helene's large wind field will continue to overspread the Florida Peninsula and Keys tonight, with low-level shear/SRH becoming increasingly favorable for low-topped supercells with a potential tornado threat. Low-topped supercell potential prior to 12Z Thursday morning remains uncertain, with inland instability expected to remain relatively limited. Outer rain bands could begin to affect the western Peninsula later tonight, while convection may persist near a convergence zone near the east coast. ...Southern Appalachians vicinity into parts of the Southeast... Widespread precipitation is ongoing this evening within a corridor from the FL Panhandle into western NC/VA, but weak to locally moderate buoyancy persists east of this band, with regional VWPs and the 00Z RNK sounding depicting vertically veering wind profiles favorable for organized convection. Generally weak low/midlevel lapse rates will tend to limit storm intensity, but marginal supercell potential may persist through the evening, with a threat of isolated damaging gusts and possibly a tornado. ...Northern ID/northeast WA/northwest MT... While low-level moisture is limited, steep lapse rates and ascent attendant to an approaching mid/upper-level shortwave trough are supporting a high-based storm cluster currently moving across the ID Panhandle. This cluster has a history of 60-65 mph gusts, and will move across northwest MT early this evening, with a continued threat of strong to locally severe gusts. ..Dean.. 09/26/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Sep 25 2024 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN APPALACHIANS INTO PARTS OF THE SOUTHEAST AND FLORIDA... ...SUMMARY... Isolated strong to severe storms are possible this evening from the southern Appalachians into parts of the Southeast. Some tornado threat may develop later tonight over Florida, in association with Hurricane Helene. ...Florida... Hurricane Helene is forecast to intensify and move north to north-northeastward across the southeast Gulf of Mexico tonight; see NHC forecasts/advisories for more information. Helene's large wind field will continue to overspread the Florida Peninsula and Keys tonight, with low-level shear/SRH becoming increasingly favorable for low-topped supercells with a potential tornado threat. Low-topped supercell potential prior to 12Z Thursday morning remains uncertain, with inland instability expected to remain relatively limited. Outer rain bands could begin to affect the western Peninsula later tonight, while convection may persist near a convergence zone near the east coast. ...Southern Appalachians vicinity into parts of the Southeast... Widespread precipitation is ongoing this evening within a corridor from the FL Panhandle into western NC/VA, but weak to locally moderate buoyancy persists east of this band, with regional VWPs and the 00Z RNK sounding depicting vertically veering wind profiles favorable for organized convection. Generally weak low/midlevel lapse rates will tend to limit storm intensity, but marginal supercell potential may persist through the evening, with a threat of isolated damaging gusts and possibly a tornado. ...Northern ID/northeast WA/northwest MT... While low-level moisture is limited, steep lapse rates and ascent attendant to an approaching mid/upper-level shortwave trough are supporting a high-based storm cluster currently moving across the ID Panhandle. This cluster has a history of 60-65 mph gusts, and will move across northwest MT early this evening, with a continued threat of strong to locally severe gusts. ..Dean.. 09/26/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Sep 25 2024 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN APPALACHIANS INTO PARTS OF THE SOUTHEAST AND FLORIDA... ...SUMMARY... Isolated strong to severe storms are possible this evening from the southern Appalachians into parts of the Southeast. Some tornado threat may develop later tonight over Florida, in association with Hurricane Helene. ...Florida... Hurricane Helene is forecast to intensify and move north to north-northeastward across the southeast Gulf of Mexico tonight; see NHC forecasts/advisories for more information. Helene's large wind field will continue to overspread the Florida Peninsula and Keys tonight, with low-level shear/SRH becoming increasingly favorable for low-topped supercells with a potential tornado threat. Low-topped supercell potential prior to 12Z Thursday morning remains uncertain, with inland instability expected to remain relatively limited. Outer rain bands could begin to affect the western Peninsula later tonight, while convection may persist near a convergence zone near the east coast. ...Southern Appalachians vicinity into parts of the Southeast... Widespread precipitation is ongoing this evening within a corridor from the FL Panhandle into western NC/VA, but weak to locally moderate buoyancy persists east of this band, with regional VWPs and the 00Z RNK sounding depicting vertically veering wind profiles favorable for organized convection. Generally weak low/midlevel lapse rates will tend to limit storm intensity, but marginal supercell potential may persist through the evening, with a threat of isolated damaging gusts and possibly a tornado. ...Northern ID/northeast WA/northwest MT... While low-level moisture is limited, steep lapse rates and ascent attendant to an approaching mid/upper-level shortwave trough are supporting a high-based storm cluster currently moving across the ID Panhandle. This cluster has a history of 60-65 mph gusts, and will move across northwest MT early this evening, with a continued threat of strong to locally severe gusts. ..Dean.. 09/26/2024 Read more

5-Day Uncertainty Track last updated Wed, 25 Sep 2024 23:36:40 GMT


Wind Speed Probabilities last updated Wed, 25 Sep 2024 21:29:01 GMT

Issued at 600 PM CST Wed Sep 25 2024 408 WTPZ35 KNHC 252336 TCPEP5 BULLETIN Tropical Storm John Intermediate Advisory Number 12A NWS National Hurricane Center Miami FL EP102024 600 PM CST Wed Sep 25 2024 ...JOHN CONTINUES TO STRENGTHEN... ...THREAT OF CATASTROPHIC LIFE-THREATENING FLASH FLOODING AND MUDSLIDES CONTINUES OVER PORTIONS OF SOUTHERN MEXICO... SUMMARY OF 600 PM CST...0000 UTC...INFORMATION ---------------------------------------------- LOCATION...16.9N 101.8W ABOUT 125 MI...200 KM W OF ACAPULCO MEXICO ABOUT 55 MI...90 KM SSW OF ZIHUATANEJO MEXICO MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...NNW OR 340 DEGREES AT 5 MPH...7 KM/H MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Tecpan de Galeana to Lazaro Cardenas A Hurricane Watch is in effect for... * Acapulco to Tecpan de Galeana * Lazaro Cardenas to Punta San Telmo A Tropical Storm Warning is in effect for... * Punta Maldonado to Acapulco * Lazaro Cardenas to Punta San Telmo A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area, this is case within 12 to 24 hours. Preparations to protect life and property should be rushed to completion. A Hurricane Watch means that hurricane conditions are possible within the watch area, in this case within 12 hours. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 600 PM CST (0000 UTC), the center of Tropical Storm John was located near latitude 16.9 North, longitude 101.8 West. John is moving toward the north-northwest near 5 mph (7 km/h). This motion should continue for the next day or so, followed by a gradual turn to the west-northwest on Friday. On the forecast track, the center of John is forecast to approach the southwestern coast of Mexico early on Thursday and be inland on Friday. Recent data from aircraft reconnaissance indicate that the maximum sustained winds have increased to near 60 mph (95 km/h) with higher gusts. John is forecast to strengthen into a hurricane as it approaches the coast of southern Mexico on Thursday. Tropical-storm-force winds extend outward up to 150 miles (240 km) from the center. The estimated minimum central pressure based on recent dropsonde data is 984 mb (29.06 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Through Friday, Tropical Storm John is expected to produce additional rainfall amounts of 10 to 20 inches with isolated totals around 30 inches across portions of the Mexican States of Guerrero, Oaxaca and Michoacan. For a complete depiction of forecast rainfall associated with John, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep5.shtml?rainqpf STORM SURGE: A dangerous storm surge is expected to produce coastal flooding near and to the east of where the center makes landfall. Near the coast, the surge will be accompanied by large and destructive waves. WIND: Hurricane conditions are expected along the coast within the hurricane warning area Thursday. Winds are expected to first reach tropical storm strength as early as tonight, making outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. Tropical storm conditions are expected to first reach the coast within the tropical storm warning area as early as tonight. SURF: Swells associated with John are forecast to continue to affect the coast of southern Mexico through the week, with the potential for dangerous surf and rip currents. Please see local statements for more information. NEXT ADVISORY ------------- Next complete advisory at 900 PM CST. $$ Forecaster Hagen

...JOHN CONTINUES TO STRENGTHEN... ...THREAT OF CATASTROPHIC LIFE-THREATENING FLASH FLOODING AND MUDSLIDES CONTINUES OVER PORTIONS OF SOUTHERN MEXICO... As of 6:00 PM CST Wed Sep 25 the center of John was located near 16.9, -101.8 with movement NNW at 5 mph. The minimum central pressure was 984 mb with maximum sustained winds of about 60 mph.

000
ABPZ20 KNHC 252332
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Wed Sep 25 2024

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

Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Storm John, located just south of southwestern Mexico.

Tropical cyclone formation is not expected during the next 7 days.

&&
Public Advisories on Tropical Storm John are issued under WMO
header WTPZ35 KNHC and under AWIPS header MIATCPEP5.
Forecast/Advisories on Tropical Storm John are issued under
WMO header WTPZ25 KNHC and under AWIPS header MIATCMEP5.

$$
Forecaster Hagen

No watches are valid as of Wed Sep 25 22:27:02 UTC 2024.

No Mesoscale Discussions are in effect as of Wed Sep 25 22:27:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0442 PM CDT Wed Sep 25 2024 Valid 271200Z - 031200Z Hurricane Helene will pull tropical moisture northward and absorb into a cutoff upper low in the Tennessee Valley region on Friday. This cutoff low will remain through at least Saturday before the pattern becomes more progressive. The combination of cool and moist conditions associated with this upper pattern will alleviate most fire weather concerns across the eastern CONUS through the extended period. Ridging will result in warm and dry conditions across much of the western CONUS during the period. While critically dry fuels are mostly sparse across the western CONUS presently, this extended warm/dry period may result in larger regions of critically dry fuels (particularly fine fuels) by the end of the weekend when the next trough crosses the western CONUS. At this time the forecast winds/relative humidity are not strong/dry enough to warrant any Critical probabilities, especially given the questionable/sparse dry fuels presently. ..Bentley.. 09/25/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more