Tag Archives: HWISI

Hurricane Sam Peaks Just Shy of Cat. 5

Hurricane Sam peaked just shy of Category 5 on the Saffir-Simpson Scale on Sunday. At 11:00 p.m. EDT on Sunday the center of Hurricane Sam was located at latitude 14.7°N and longitude 50.8°W which put it about 850 miles (1365 km) east-southeast of the Northern Leeward Islands. Sam moving toward the northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 170 m.p.h. (280 km/h). The minimum surface pressure was 943 mb.

The National Hurricane Center indicated that the maximum sustained wind speed in Hurricane Sam may have peaked at 155 m.p.h. (250 km/h) on Sunday afternoon before an Eyewall Replacement Cycle halted intensification. The inner end of a rainband wrapped around the existing small eye and eyewall at the center of Hurricane Sam. There were two concentric eyewalls for a period of time and then the inner eyewall began to dissipate. Low level convergence became primarily concentrated on the outer eyewall. The outer eyewall had a diameter of 16 miles (26 km). The western side of the outer eyewall was weaker and the rainbands on the western side of Hurricane Sam were also weaker.

The size of the circulation around Hurricane Sam only increased slightly as a result of the Eyewall Replaement Cycle. Winds to hurricane force extended out 30 miles (50 km) from the center of Sam. Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation. The Hurricane Intensity Index (HII) was 29.9. The Hurricane Size Index (HSI) was 9.8 and the Hurricane Wind Intensity Size Index (HWISI) was 39.7.

Hurricane Sam will move through an environment capable of sustaining a major hurricane during the next 48 hours. Sam will move over water where the Sea Surface Temperatures are near 28˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. The current Eyewall Replacement Cycle will cause Hurricane Sam to weaken until the outer eyewall becomes full developed. Additional Eyewall Replacement Cycles could occur which would cause fluctuations in the intensity of Hurricane Sam.

Hurricane Sam will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high will steer Sam toward the northwest during the next 48 hours. On its anticipated track Hurricane Sam could be east of the Northern Leeward Islands by Wednesday.

Hurricane Sam Rapidly Intensifies to Cat. 4

Hurricane Sam rapidly intensified to Category 4 on the Saffir-Simpson Scale on Saturday night. At 11:00 p.m. EDT on Saturday the center of Hurricane Sam was located at latitude 13.5°N and longitude 49.0°W which put it about 990 miles (1595 km) east-southeast of the Northern Leeward Islands. Sam moving toward the west-northwest at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (280 km/h). The minimum surface pressure was 943 mb.

A NOAA plane conducting a research mission in Hurricane Sam fund that Sam had rapidly intensified to Category 4 on the Saffir-Simpson Scale. A circular eye with a diameter of 12 miles (19 km) was present at the center of Hurricane Sam. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Sam. Storms near the core generated strong upper level divergence that pumped mass away from the hurricane in all directions.

The circulation around Hurricane Sam was relatively small. Winds to hurricane force extended out 30 miles (50 km) from the center of Sam. Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation. The Hurricane Intensity Index (HII) for Hurricane Sam was 30.0. The Hurricane Size Index (HSI) was 9.2 and the Hurricane Wind Intensity Size Index (HWISI) was 39.2.

Hurricane Sam will move through an environment capable of sustaining a major hurricane during the next 48 hours. Sam will move over water where the Sea Surface Temperatures are near 28˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. The NOAA aircraft did report that there was some drier air in the middle troposphere in the environment around Hurricane Sam. The drier air could weaken Sam if it gets pulled into the core of the circulation. In addition, if the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. An eyewall replacement cycle would cause Hurricane Sam to weaken.

Hurricane Sam will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high will steer Sam toward the west-northwest during the next few days. On its anticipated track Hurricane Sam could be east of the Northern Leeward Islands by the middle of next week.

Typhoon Mindulle Rapidly Intensifies to Equivalent of Cat. 5 Hurricane

Typhoon Mindulle rapidly intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Saturday night. At 11:00 p.m. EDT on Saturday the center of Typhoon Mindulle was located at latitude 18.7°N and longitude 136.8°E which put it about 510 miles (825 km) southwest of Iwo To. Mindulle moving toward the northwest at 4 m.p.h. (6 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h). The minimum surface pressure was 915 mb.

Typhoon Mindulle continued to intensify rapidly over the Western North Pacific Ocean on Saturday night. A circular eye with a diameter of 18 miles (29 km) was present at the center of Mindulle. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Mindulle. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the typhoon. The removal of large amounts of mass allowed the surface pressure to decrease rapidly.

The circulation around Typhoon Mindulle was more than twice as large as the circulation of Hurricane Sam which was over the Atlantic Ocean. Winds to typhoon force extended out 50 miles (80 km) from the center of Mindulle. Winds to tropical storm force extended out 210 miles (340 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Mindulle was 35.0. The Hurricane Size Index (HSI) was 19.4 and the Hurricane Wind Intensity Size Index (HWISI) was 54.4.

Typhoon Mindulle will move through an environment capable of sustaining a powerful typhoon during the next 36 hours. Mindulle will move over water where the Sea Surface Temperatures are near 30˚C. It will move into a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Mindulle may be near its peak intensity. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. That structure would start an eyewall replacement cycle that could cause Typhoon Mindulle to weaken. Typhoon Mindulle will move slowly. The strong winds in Mindulle could mix cooler water to the surface. That would also cause Mindulle to weaken.

Typhoon Mindulle will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next several days. The high will steer Mindulle slowly toward the northwest during the next several days. On its anticipated track Typhoon Mindulle could be west of Iwo To in three days.

Typhoon Mindulle Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Mindulle rapidly intensified to the equivalent of a major hurricane on Saturday. At 11:00 a.m. EDT on Saturday the center of Typhoon Mindulle was located at latitude 18.3°N and longitude 137.3°E which put it about 525 miles (850 km) south-southwest of Iwo To. Mindulle moving toward the north-northwest at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h). The minimum surface pressure was 942 mb.

Typhoon Mindulle rapidly intensified to the equivalent of a major hurricane over the Western North Pacific Ocean on Saturday. A circular eye was present at the center of Mindulle. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Mindulle. Storms near the core generated upper level divergence that pumped large quantities of mass away from the typhoon. The removal of large amounts of mass allowed the surface pressure to decrease rapidly.

The circulation around Typhoon Mindulle was about twice as large as the circulation of Hurricane Sam which was over the Atlantic Ocean. Winds to typhoon force extended out 45 miles (75 km) from the center of Mindulle. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Mindulle was 25.1. The Hurricane Size Index (HSI) was 16.0 and the Hurricane Wind Intensity Size Index (HWISI) was 41.1.

Typhoon Mindulle will move through an environment favorable for intensification during the next 24 hours. Mindulle will move over water where the Sea Surface Temperatures are near 30˚C. It will move into a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Mindulle will continue to intensify during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. That structure would start an eyewall replacement cycle that could cause Typhoon Mindulle to weaken.

Typhoon Mindulle will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next several days. The high will steer Mindulle slowly toward the northwest during the next several days. On its anticipated track Typhoon Mindulle could be west of Iwo To in three or four days.

Sam Intensifies to a Major Hurricane

Hurricane Sam intensified to a major hurricane on Saturday morning. At 11:00 a.m. EDT on Saturday the center of Hurricane Sam was located at latitude 12.9°N and longitude 47.6°W which put it about 1095 miles (1760 km) east-southeast of the Northern Leeward Islands. Sam moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (225 km/h). The minimum surface pressure was 960 mb.

Hurricane Sam intensified to a major hurricane over the tropical Atlantic Ocean on Saturday morning. A well formed circular eye was present at the center of Hurricane Sam. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Sam. Storms near the core generated strong upper level divergence that pumped mass away from the hurricane in all directions.

The circulation around Hurricane Sam was relatively small. Winds to hurricane force extended out 25 miles (40 km) from the center of Sam. Winds to tropical storm force extended out 80 miles (130 km) from the center of circulation. The Hurricane Intensity Index (HII) for Hurricane Sam was 22.1. The Hurricane Size Index (HSI) was 7.4 and the Hurricane Wind Intensity Size Index (HWISI) was 29.5.

Hurricane Sam will move through an environment favorable for intensification during the next 24 hours. Sam will move over water where the Sea Surface Temperatures are near 28˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Sam will continue to intensify during the next 24 hours. Sam could strengthen to Category 5 on the Saffir-Simpson Scale.

Hurricane Sam will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high will steer Sam toward the west-northwest during the next few days. On its anticipated track Hurricane Sam could be east of the Northern Leeward Islands by the middle of next week.

Elsewhere over the Atlantic Ocean, former Subtropical Storm Teresa weakened north of Bermuda. At 11:00 a.m. EDT on Saturday the center of Subtropical Depression Teresa was located at latitude 34.3°N and longitude 65.0°W which put it about 140 miles (225 km) north of Bermuda. Teresa was stationary. The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1009 mb.

Typhoon Chanthu Moves Away from Taiwan

Typhoon Chanthu moved away from Taiwan on Sunday. At 11:00 a.m. EDT on Sunday the center of Typhoon Chanthu was located at latitude 26.8°N and longitude 122.7°E which put it about 105 miles (165 km) northeast of Taipei, Taiwan. Chanthu was moving toward the north-northeast at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h). The minimum surface pressure was 965 mb.

Typhoon Chanthu moved away from Taiwan on Sunday and the weather conditions were improving there. The core of Chanthu passed east of Taiwan and so it remained intact. A small circular eye was present at the center of Typhoon Chanthu. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Multiple bands of showers and thunderstorms were revolving around the core of Chanthu. Storms near the core generated upper level divergence that pumped mass away to the north of the typhoon.

The overall circulation of Typhoon Chanthu was larger after it moved past Taiwan. Winds to typhoon force extended out 25 miles (40 km) from the center of Chanthu. Winds to tropical storm force extended out 190 miles (305 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Chanthu was 19.2. The Hurricane Size Index (HSI) was 10.7 and the Hurricane Wind Intensity Size Index (HWISI) was 29.9. Typhoon Chanthu was capable of causing regional serious damage.

Typhoon Chanthu will move through an environment that will be mostly unfavorable for intensification during the next 36 hours. Chanthu will move over water where the Sea Surface Temperature is near 29˚C. An upper level trough over eastern China will produce southwesterly winds that will blow toward the top of Chanthu’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will likely be strong enough to cause Typhoon Chanthu to weaken gradually.

Typhoon Chanthu will move around the western side of a subtropical high pressure system over the Western North Pacific Ocean. The high will steer Chanthu toward the north during the next 24 hours. On its anticipated track Typhoon Chantu will continue to move away from Taiwan. Chanthu could approach the coast of Chine south of Shanghai in 24 hours. Typhoon Chanthu will bring gusty winds and locally heavy rain to the parts of east coast of China on Monday.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Conson weakened near the coast of Vietnam. At 11:00 a.m. EDT on Sunday the center of Tropical Depression Conson was located at latitude 15.4°N and longitude 109.1°E which put it about 70 miles (110 km) southeast of Da Nang, Vietnam. Conson was stationary. The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1003 mb.

Typhoon Chanthu Brings Wind and Rain to Taiwan

Typhoon Chanthu brought wind and rain to Taiwan on Saturday morning. At 11:00 a.m. EDT on Saturday the center of Typhoon Chanthu was located at latitude 22.2°N and longitude 121.8°E which put it about 100 miles (160 km) south-southeast of Hualien, Taiwan. Chanthu was moving toward the north-northeast at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (270 km/h). The minimum surface pressure was 938 mb.

Bands in the northwestern part of Typhoon Chanthu brought wind and rain to eastern Taiwan on Saturday morning. Typhoon Chanthu appeared to be in the middle of another eyewall replacement cycle. A small eye was present at the center of Chanthu. The eye was surrounded by concentric eyewalls. The strongest winds were occurring in the innermost eyewall. Bands of showers and thunderstorms were revolving around the core of Typhoon Chanthu. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The current eyewall replacement cycle increased the overall size of the circulation around Typhoon Chanthu. Winds to typhoon force extended out 35 miles (55 km) from the center of Chanthu. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Chanthu was 28.3. The Hurricane Size Index (HSI) was 12.5 and the Hurricane Wind Intensity Size Index (HWISI) was 40.8. Typhoon Chanthu was capable of causing regional severe damage.

Typhoon Chanthu will move over water capable of supporting an intense typhoon during the next 24 hours. Chanthu will move over water where the Sea Surface Temperature is near 30˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. The current eyewall replacement cycle could cause Typhoon Chanthu to weaken if the innermost eyewall dissipates.

Typhoon Chanthu will move around the western end of a high pressure system over the Western North Pacific. The high pressure system will steer Chanthu toward the north during the next 36 hours. On its anticipated track the center of Typhoon Chanthu will be near northeastern Taiwan in 18 hours. Typhoon Chanthu will drop very heavy rain over eastern Taiwan. The risk of flash floods is very high. Even though the core of Chanthu may pass just east of Taiwan, strong winds are likely to cause damage along the east coast of Taiwan.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Conson was approaching toward central Vietnam. At 11:00 a.m. EDT on Saturday the center of Tropical Storm Conson was located at latitude 15.4°N and longitude 109.0°E which put it about 65 miles (105 km) southeast of Da Nang, Vietnam. Conson was moving toward the west-southwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 997 mb.

Hurricane Larry Races Toward Newfoundland

Hurricane Larry raced toward Newfoundland on Friday morning. At 11:00 p.m. EDT on Friday the center of Hurricane Larry was located at latitude 40.0°N and longitude 60.5°W which put it about 595 miles (955 km) southwest of Cape Race, Newfoundland. Larry was moving toward the north-northeast at 29 m.p.h. (46 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (150 km/h). The minimum surface pressure was 971 mb.

A Hurricane Warning was in effect for the portion of the coast from Arnold’s Cove to Jones Harbour, Newfoundland. The Hurricane Warning included St. John’s. Tropical Storm Warnings were in effect for the portions of the coast from Francios to Arnold’s Cove and from Jones Harbour to Fogo Island, Newfoundland.

The structure of Hurricane Larry changed as it raced toward the north-northeast. A rainband wrapped around the existing eye and eyewall and it appeared that concentric eyewalls may have formed. Microwave satellite imagery showed indications of a smaller inner eye inside a much larger outer eye. Drier air was being pulled into the circulation around Hurricane Larry. Zones of drier air with fewer clouds were beginning to appear between the rainbands.

The circulation around Hurricane Larry was large. Winds to hurricane force extended out 80 miles (130 km) from the center of Larry. Winds to tropical storm force extended out 240 miles (390 km) from the center of circulation. The Hurricane Intensity Index (HII) for Larry was 11.5. The Hurricane Size Index (HSI) was 27.9 and the Hurricane Wind Intensity Size Index (HWISI) was 39.4. Hurricane Larry was about 60% of the size of Hurricane Sandy (2012).

Hurricane Larry will move through an environment that will allow Larry to maintain its intensity until it reaches Newfoundland. Larry will move over cooler water when it moves north of the Gulf Stream. An upper level trough over the eastern U.S. will produce southwesterly winds that will blow toward the top of Larry’s circulation. Those winds will cause moderate vertical wind shear. However, the southwesterly winds will also contribute to upper level divergence to the northeast of Hurricane Larry. Enhanced upper level divergence will allow the pressure at the surface to remain low. In addition, Hurricane Larry will begin to make a transformation to an extratropical cyclone when it nears Newfoundland.

The upper trough over the eastern U.S. will steer Hurricane Larry rapidly toward the northeast during the next 24 hours. On its anticipated track Hurricane Larry will reach Newfoundland on Friday night. Larry will bring strong winds and locally heavy rain to southeast Newfoundland. Widespread power outages could occur. Heavy rain could cause flash floods in some locations.

Typhoon Chanthu Brings Wind and Rain to Northeast Luzon

Typhoon Chanthu brought wind and rain to northeastern Luzon on Friday. At 5:00 a.m. EDT on Friday the center of Typhoon Chanthu was located at latitude 18.3°N and longitude 123.1°E which put it about 100 miles (160 km) east of Aparri, Philippines. Chanthu was moving toward the northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 165 m.p.h. (265 km/h) and there were wind gusts to 200 m.p.h. (320 km/h). The minimum surface pressure was 915 mb.

Even though the center of Typhoon Chanthu was passing northeast of northeastern Luzon, bands on the western side of Chanthu brought gusty wind and heavy rain to northeastern Luzon. Typhoon Chanthu strengthened back to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale after it completed an eyewall replacement cycle on Thursday. A circular eye was present at the center of Chanthu. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Storms near the core of Chanthu generated strong upper level divergence that pumped mass away from the typhoon in all directions.

The circulation around Typhoon Chanthu was relatively small. Winds to typhoon force extended out 45 miles (75 km) from the center of Chanthu. Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Chanthu was 36.8. The Hurricane Size Index (HSI) was 14.1 and the Hurricane Wind Intensity Size Index (HWISI) was 50.9. Typhoon Chanthu was capable of causing regional catastrophic damage.

Typhoon Chanthu will move over water capable of supporting an intense typhoon during the next 24 hours. Chanthu will move over water where the Sea Surface Temperature is near 30˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. If the inner end of a rainband wraps around the existing eye and eyewall, another eyewall replacement cycle could start. If another eyewall replacement cycle occurs, Typhoon Chanthu would weaken, but the size of the circulation would increase.

Typhoon Chanthu will move around the western end of a high pressure system during the next few days. The high pressure system will steer Chanthu toward the northwest during the next 24 hours. On its anticipated track Typhoon Chanthu will gradually move away from northeastern Luzon. Chantu will approach southern Taiwan in 24 hours. Typhoon Chanthu will bring very strong winds and heavy rain to Taiwan. Widespread flash floods could occur.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Conson moved toward central Vietnam. At 5:00 a.m. EDT on Friday the center of Tropical Storm Conson was located at latitude 15.6°N and longitude 111.7°E which put it about 250 miles (400 km) east of Da Nang, Vietnam. Conson was moving toward the west at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 997 mb.

Hurricane Olaf Makes Landfall on Southern Tip of Baja California

Hurricane Olaf made landfall on southern tip of Baja California on Thursday night. At 11:00 p.m. EDT on Thursday the center of Hurricane Olaf was located at latitude 23.0°N and longitude 109.6°W which put it about 20 miles (30 km) east-northeast of Cabo San Lucas, Mexico. Olaf was moving toward the northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h). The minimum surface pressure was 974 mb.

A Hurricane Warning Was in effect for the portion of the coast from Los Barriles to Cabo San Lazaro, Mexico. The Hurricane Warning included Cabo San Lucas. Tropical Storm Warnings were in effect for the portions of the coast from Cabo San Lazaro to Puerto San Andresito, Mexico and from Los Barriles to Loreto, Mexico.

The eye of Hurricane Olaf made landfall on the southern tip of Baja California near San Jose del Cabo on Thursday night. Olaf continued to intensify right up until the center moved ashore. Hurricane Olaf strengthened to Category 2 on the Saffir-Simpson Scale prior to landfall. Winds to hurricane force extended out 35 miles (55 km) from the center of Olaf. Winds to tropical storm force extended out 105 miles (165 km) from the center of circulation. The Hurricane Intensity Index (HII) for Hurricane Olaf was 16.5. The Hurricane Size Index (HSI) was 10.5 and the Hurricane Wind Intensity Size Index (HWISI) was 27.0

Hurricane Olaf was capable of causing regional serious damage. Olaf will produce strong winds over the southern part of Baja California. Wind damage could cause widespread power outages. Hurricane Olaf will also drop heavy rain over the region and flash floods are likely to occur. Hurricane Olaf will move northwest over Baja California during the next 24 hours. Mountains will begin to disrupt the circulation and Olaf will weaken. The area of heavy rain will move northward, as will the risk for flash floods.