8:00AM Update: Centre Of Isaac Moving Into The Windward Passage & Forecast To Head For Florida Keys As A Hurricane
Saturday, August 25, 2012 9:07 am
by Rob Lightbown of Crown Weather
My overall forecast track for Isaac that I put out yesterday remains unchanged. Isaac is expected to impact the Florida Keys and south Florida on Sunday. Hurricane force winds are expected across southwestern Florida and the Florida Keys starting Sunday afternoon and continuing into Sunday night. Across the rest of south Florida, tropical storm force winds are expected from Sunday afternoon into Sunday night.
I still strongly believe that Isaac will make landfall very close to Fort Walton Beach in the Florida Panhandle on Tuesday night as a Category 2 hurricane. This means that hurricane conditions are likely from later Tuesday afternoon through Tuesday night and into Wednesday morning across much of the Florida Panhandle, including Pensacola, Panama City and Apalachicola.
I will continue to monitor Isaac extremely closely and will continue to update throughout the weekend.
For more go to:
http://www.crownweather.com/?page_id=4557
TROPICAL STORM ISAAC DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 AM EDT SAT AUG 25 2012
THE CIRCULATION OF ISAAC HAS REMAINED RELATIVELY INTACT AFTER MOVING ACROSS THE SOUTHWESTERN PENINSULA OF HAITI OVERNIGHT. BEFORE THE CENTER MOVED INLAND…HURRICANE HUNTER AIRCRAFT DATA SUGGESTED THAT THE CYCLONE HAD PEAK WINDS OF ABOUT 55 KT. ASSUMING THE CYCLONE WEAKENED A LITTLE AFTER ENCOUNTERING THE HIGH TERRAIN…THE INITIAL INTENSITY IS LOWERED TO 50 KT FOR THIS ADVISORY.
THE INITIAL MOTION ESTIMATE IS 320/12. AS A MID-LEVEL TROUGH LIFTS OUT OF THE SOUTHEASTERN UNITED STATES…ISAAC WILL MOVE GENERALLY WEST-NORTHWESTWARD AROUND THE WEST SIDE OF THE SUBTROPICAL RIDGE FOR THE NEXT THREE DAYS OR SO…AND THEN TURN NORTHWARD LATE IN THE PERIOD AS A SHORTWAVE TROUGH AMPLIFIES OVER THE EASTERN UNITED STATES. THERE HAS BEEN LITTLE CHANGE TO THE NHC FORECAST THIS
CYCLE…AND THE NEW TRACK FORECAST IS CLOSE TO THE MIDDLE OF THE GUIDANCE ENVELOPE AND LIES CLOSE TO THE GFS AND THE TVCA MULTI-MODEL CONSENSUS THROUGH 96 HOURS. BY DAY 5 THERE IS SOME DISAGREEMENT AS TO WHETHER ISAAC WILL TURN NORTHEASTWARD AHEAD OF THE SHORTWAVE TROUGH AS SHOWN BY THE GFS…UKMET…AND THE GFDL OR BE LEFT BEHIND AS SHOWN BY THE ECMWF AND HWRF. THE NHC DAY 5 POINT IS BETWEEN THE TWO CAMPS SHOWING A SLOW NORTHWARD MOTION.
GIVEN THAT THE CYCLONE HAS FARED RATHER WELL AFTER MOVING ACROSS HAITI…AND THAT THE TRACK FORECAST HAS ONLY MINIMAL INTERACTION WITH CUBA…THE INTENSITY FORECAST AFTER 12 HOURS HAS BEEN ADJUSTED UPWARD FOLLOWING THE TREND OF THE LATEST INTENSITY GUIDANCE. ISAAC IS EXPECTED TO BECOME A HURRICANE IN ABOUT 36 HOURS…WITH ADDITIONAL INTENSIFICATION EXPECTED AS THE CYCLONE MOVES INTO THE EASTERN GULF OF MEXICO IN A FAVORABLE ENVIRONMENT. THE NEW NHC INTENSITY FORECAST IS CLOSE TO THE INTENSITY CONSENSUS AIDS THROUGH 72 HOURS AND FOLLOWS A BLEND OF THE DECAY SHIPS AND LGEM AFTERWARD.
THE NEW NHC FORECAST NECESSITATES THE ISSUANCE OF A HURRICANE WARNING FOR THE FLORIDA KEYS AND A PORTION OF THE SOUTHWEST COAST OF FLORIDA AT THIS TIME.
IT IS IMPORTANT NOT TO FOCUS ON THE EXACT TRACK OF ISAAC DUE TO THE UNCERTAINTIES IN THE FORECAST AND THE FACT THAT ISAAC HAS A LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH IT.
FORECAST POSITIONS AND MAX WINDS
INIT 25/0900Z 19.0N 73.3W 50 KT 60 MPH
12H 25/1800Z 20.4N 75.0W 50 KT 60 MPH…INLAND
24H 26/0600Z 22.2N 77.6W 55 KT 65 MPH…OVER WATER
36H 26/1800Z 23.8N 80.0W 65 KT 75 MPH
48H 27/0600Z 25.0N 81.8W 70 KT 80 MPH
72H 28/0600Z 27.7N 84.9W 80 KT 90 MPH
96H 29/0600Z 30.5N 86.0W 70 KT 80 MPH…INLAND
120H 30/0600Z 32.5N 86.0W 35 KT 40 MPH…INLAND
SUMMARY OF WATCHES AND WARNINGS IN EFFECT…
A HURRICANE WARNING IS IN EFFECT FOR…
* THE FLORIDA KEYS INCLUDING THE DRY TORTUGAS
* THE WEST COAST OF FLORIDA FROM BONITA BEACH SOUTHWARD
* FLORIDA BAY
A HURRICANE WATCH IS IN EFFECT FOR…
* HAITI
* THE FLORIDA EAST COAST FROM GOLDEN BEACH SOUTHWARD
* ANDROS ISLAND IN THE BAHAMAS
A TROPICAL STORM WARNING IS IN EFFECT FOR…
* DOMINICAN REPUBLIC
* HAITI
* CUBAN PROVINCES OF CIEGO DE AVILA…SANCTI SPIRITUS…VILLA
CLARA…CAMAGUEY…LAS TUNAS…GRANMA…HOLGUIN…SANTIAGO DE
CUBA…AND GUANTANAMO
* THE BAHAMAS
* TURKS AND CAICOS ISLANDS
* THE FLORIDA EAST COAST FROM JUPITER INLET SOUTHWARD
* LAKE OKEECHOBEE
A TROPICAL STORM WATCH IS IN EFFECT FOR…
* CUBAN PROVINCES OF MATANZAS AND CIENFUEGOS
* JAMAICA
* THE FLORIDA EAST COAST NORTH OF JUPITER INLET TO SEBASTIAN INLET
* CAYMAN ISLANDS
A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA. A WARNING IS TYPICALLY ISSUED 36 HOURS BEFORE THE ANTICIPATED FIRST OCCURRENCE OF TROPICAL STORM FORCE WINDS…CONDITIONS THAT MAKE OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS. 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 THE NEXT 24 TO 36 HOURS.
A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.
A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA…GENERALLY WITHIN 48 HOURS.
INTERESTS IN THE REMAINDER OF CUBA AND THE REMAINDER OF THE FLORIDA PENINSULA SHOULD MONITOR THE PROGRESS OF ISAAC.
FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES…INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS…PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE THE UNITED STATES…PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.VALID FOR THE MORNING OF
OFFICIAL CAYMAN ISLANDS WEATHER FORECAST FOR AUGUST 25TH 2012 THROUGH THE MORNING OF AUGUST 26TH 2012. ISSUED BY CAYMAN ISLANDS WEATHER STATION
SYNOPSIS:
The National Hurricane Center in Miami, Florida, is issuing advisories on Tropical Storm Isaac, which 4 a.m. was located near 19.0 N. 73.3 W. or about 150 miles southeast of Guantanamo, Cuba and is moving towards the northwest near 14 mph with maximum sustained winds near 60 mph.
THE GOVERNMENT OF CAYMAN ISLANDS HAS ISSUED A TROPICAL STORM WATCH FOR THE CAYMAN ISLANDS. ALL RESIDENTS ARE URGED TO MONITOR PROGRESS OF THIS STORM.
Showers and cloudiness associated with Tropical Storm Isaac is expected over the Cayman area from today.
THE FORECAST:
Today: Partly cloudy to cloudy skies with a 60% chance of showers and thunder over the Sister Islands, and a 40% chance of showers and thunder over Grand Cayman. Some showers may be locally heavy at times and may lead to flooding of low-lying area. Temperatures will rise to the mid 80’s. Winds will be northeast 10 to 15 knots with higher gusts especially in around heavy showers. Seas will be moderate to rough with wave heights of 4 to 6 feet. Small craft warning remains in effect.
Tonight: Cloudy skies with a 60% chance of showers and thunder. Some showers may be locally heavy at times and may lead to flooding of low-lying area.Temperatures will fall to the upper 70’s. Winds will be northerly 10 to 15 knots with higher gusts especially in around heavy showers. Seas will be moderate to rough with wave heights of 4 to 6 feet. Small craft warning remains in effect.
TIDES:
Today: Low 8:53 a.m. High 6:27 p.m.
Tomorrow: Low 10:01 a.m. High 6:54 p.m.
SUNSET: 6:45 p.m. Today. SUNRISE: 6:09 a.m. Tomorrow.
OUTLOOK: is for locally heavy showers to continue through Monday morning as Tropical Storm Isaac passes north of central Cuba. Heavy showers may lead to flooding of low lying area.
