Caribbean-On-Line's Caribbean Hurricane Blog



Hurricane Isaac

Tropical Storm Isaac Update

Published on August 26, 2012 8:20 AM | Comments

This morning Isaac is off the coast of Cuba and forecast to make landfall late in the week somewhere near the end of the Florida panhandle:

TROPICAL STORM ISAAC DISCUSSION NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
500 AM EDT SUN AUG 26 2012

WHILE THE SATELLITE PRESENTATION OF ISAAC REMAINS SOMEWHAT
UNIMPRESSIVE...WITH DEEP CONVECTION LIMITED TO A RATHER SMALL AREA
NORTH AND EAST OF THE CENTER...AIRCRAFT DATA SUGGEST THAT THE
CYCLONE HAS STRENGTHENED A LITTLE OVERNIGHT. PEAK 850-MB
FLIGHT-LEVEL WINDS OF 69 KT IN THE NORTHEAST QUADRANT ADJUST TO AN
INTENSITY OF 55 KT...WHICH IS THE VALUE FOR THIS ADVISORY. AIRCRAFT
DATA INDICATE THAT THE MINIMUM PRESSURE HAS ALSO DROPPED A LITTLE...
TO 995 MB. ISAAC STILL APPEARS TO BE BATTLING THE EFFECTS OF SOME
LOW- TO MID-LEVEL DRY AIR IN THE WESTERN SIDE OF THE CIRCULATION...
AS SEEN IN UPPER-AIR DATA FROM MIAMI AND KEY WEST. ASIDE FROM
THIS...HOWEVER...CONDITIONS APPEAR FAVORABLE FOR STEADY
INTENSIFICATION AS THE CYCLONE MOVE ACROSS THE FLORIDA STRAITS AND
INTO THE EASTERN GULF OF MEXICO. WATERS ALONG THE FORECAST TRACK ARE
VERY WARM...AND UPPER-LEVEL WINDS ARE FORECAST BY THE GLOBAL MODELS
TO BECOME CONDUCIVE FOR STRENGTHENING. THE NEW NHC FORECAST IS
SIMILAR TO THE PREVIOUS ONE...BUT SHOWS A LITTLE SLOWER RATE OF
STRENGTHENING FOR THE FIRST COUPLE OF DAYS...TRENDING TOWARD THE
LATEST CYCLE OF GUIDANCE.

THE INITIAL MOTION ESTIMATE IS 305/16...A LITTLE FASTER THAN BEFORE.
AS THE UPPER-LOW TO THE WEST OF ISAAC RETREATS WESTWARD AND THE
CLOSED LOW OVER THE MID-ATLANTIC STATES LIFTS NORTHWARD...ISAAC
WILL MOVE GENERALLY WEST-NORTHWESTWARD OR NORTHWESTWARD AROUND THE
WESTERN PERIPHERY OF THE ATLANTIC SUBTROPICAL RIDGE FOR THE NEXT 48
HOURS. BEYOND THAT TIME...THERE IS CONSIDERABLE SPREAD IN THE MODEL
GUIDANCE. MOST OF THE MODELS...WITH THE EXCEPTION OF THE UKMET...NO
LONGER SHOW ISAAC RECURVING AHEAD OF A SHORTWAVE TROUGH MOVING
EASTWARD ACROSS THE EASTERN UNITED STATES. ONE CAMP OF GUIDANCE...
INCLUDING THE GFS...HWRF...AND GFS ENSEMBLE MEAN SHOW A
NORTHWESTWARD TRACK TOWARD THE CENTRAL GULF COAST AS THE SHORTWAVE
BYPASSES ISAAC COMPLETELY. THE ECMWF AND GFDL SHOW HAVE MORE OF A
WEAKNESS IN THE RIDGE AND SHOW ISAAC TURNING NORTHWARD TOWARD THE
EASTERN GULF COAST. THE NEW NHC FORECAST IS FASTER THAN THE
PREVIOUS ONE THROUGH MUCH OF THE PERIOD...BUT IS ALONG THE PREVIOUS
TRACK THROUGH 36 HOURS. AFTER THAT TIME...A SIGNIFICANT WESTWARD
ADJUSTMENT WAS MADE...AND THE NEW NHC TRACK IS CLOSE TO THE TVCA
MULTI-MODEL CONSENSUS AND THE ECMWF...SHOWING A NORTH-NORTHWESTWARD
AND NORTHWARD TURN AT DAYS 3 THROUGH 5. GIVEN THE LARGE SPREAD IN
THE GUIDANCE...CONFIDENCE IN THE LONG-RANGE TRACK FORECAST IS QUITE
LOW...AND IT IS TOO EARLY TO DETERMINE EXACTLY WHERE AND WHEN ISAAC
WILL MAKE LANDFALL ALONG THE GULF COAST. FURTHER ADJUSTMENTS TO THE
TRACK MAY BE NECESSARY LATER TODAY.

THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT
FORECAST TRACK SINCE SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE
CENTER.

GIVEN THE NEW NHC FORECAST...A HURRICANE WATCH HAS BEEN ISSUED FOR A
PORTION OF THE NORTHERN GULF COAST.



TROPICAL STORM ISAAC DISCUSSION NUMBER 17

Published on August 25, 2012 8:55 AM | Comments

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.



Isaac Gains Strength

Published on August 25, 2012 8:49 AM | Comments



VI Port Authority Provides Flight Information and Port Status Updates

Published on August 23, 2012 1:06 PM | Comments

The Virgin Islands Port Authority's Interim Executive Director, Don Mills Esq., issued the following update on the status of flights and the VIPA's air and seaports as Tropical Storm Isaac passes the U.S. Virgin Islands:

American Airlines
-Canceled today's midday flight from St. Croix to Miami.
-Operating its Miami, Florida to St. Thomas flight AA505/AA672, arriving at 1:35pm and departing at 3:00pm.
-Operating its Miami, Florida to St. Thomas flight AA1819, arriving at 8:00pm. This is the scheduled daily over-nighter.

American Eagle:
-Operating its San Juan to St. Thomas flight AA4874/AA4833, arriving at 6:00pm and departing at 6:30pm.
-Thus far, American Eagle has not canceled its San Juan, Puerto Rico to St. Croix flight scheduled to arrive at 6:30 p.m today.

LIAT, Ltd.:
-Resuming operations at CEKA with its midday flight, LI553, scheduled arrival at 12:45pm, scheduled departure at 1:30pm.
-VIPA has not yet received a report on when this airline will resume operations at HERA

Jet Blue
-Operating as normal with no cancellations

Delta
-Operating its flight from Atlanta, Georgia to St. Thomas with scheduled arrival at 2:08pm, scheduled departure at 2:58pm.

Cape Air
- All flights remain cancelled until further notice

Seaborne Airlines
-All flights remain cancelled from the seaports and airports until Friday, Aug. 24th

Spirit
-No scheduled flights today

United and US Airways
-No scheduled flights through Saturday, Aug. 25th

Both the Cyril E. King Airport on St. Thomas and the Henry E. Rohlsen Airport are open, but all seaports throughout the territory remain closed until further notice from the U.S. Coast Guard.



Latest watches and warnings for Tropical Storm Isaac

Published on August 23, 2012 12:13 PM | Comments

Next advisory at 2 PM EST:

BULLETIN
TROPICAL STORM ISAAC ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012
1100 AM AST THU AUG 23 2012

...ISAAC CONTINUES MOVING WESTWARD TO THE SOUTH OF THE VIRGIN
ISLANDS AND PUERTO RICO...

SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.6N 65.4W
ABOUT 200 MI...320 KM SSE OF SAN JUAN PUERTO RICO
ABOUT 360 MI...575 KM ESE OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WARNING IS IN EFFECT FOR...
* SOUTH COAST OF DOMINICAN REPUBLIC FROM ISLA SAONA WESTWARD TO THE
HAITI-DOMINICAN REPUBLIC SOUTHERN BORDER
* HAITI

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* BRITISH VIRGIN ISLANDS
* PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS
* NORTH COAST OF DOMINICAN REPUBLIC FROM THE HAITI-DOMINICAN
REPUBLIC NORTHERN BORDER EASTWARD TO NORTH OF ISLA SAONA

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* SOUTHEASTERN BAHAMAS INCLUDING THE ACKLINS...CROOKED
ISLAND...LONG CAY...THE INAGUAS...MAYAGUANA...AND THE RAGGED
ISLANDS AND THE TURKS AND CAICOS ISLANDS

A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED
SOMEWHERE WITHIN THE WARNING AREA. 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 WITHIN 36 HOURS.

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.

INTERESTS IN CUBA...JAMAICA...AND ELSEWHERE IN THE BAHAMAS SHOULD
MONITOR THE PROGRESS OF ISAAC.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...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.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 AM AST...1500 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS
LOCATED NEAR LATITUDE 15.6 NORTH...LONGITUDE 65.4 WEST. ISAAC IS
MOVING TOWARD THE WEST NEAR 15 MPH...24 KM/H. A TURN TOWARD THE
WEST-NORTHWEST IS EXPECTED THIS AFTERNOON...AND A WEST-
NORTHWESTWARD MOTION IS EXPECTED TO CONTINUE THROUGH SATURDAY. ON
THE FORECAST TRACK...THE CENTER OF ISAAC SHOULD PASS SOUTH OF
PUERTO RICO TODAY...AND BE NEAR THE SOUTH COAST OF THE DOMINICAN
REPUBLIC AND HAITI ON FRIDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH HIGHER
GUSTS. STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND
ISAAC COULD BECOME A HURRICANE AS IT NEARS THE DOMINICAN REPUBLIC
AND HAITI.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140 MILES...220 KM
FROM THE CENTER. NOAA BUOY 42060 RECENTLY REPORTED 1-MINUTE MEAN
WINDS OF 40 MPH...65 KM/HR...AND A WIND GUST OF 47 MPH...76 KM/HR.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB...29.62 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE SUBSIDING OVER THE LEEWARD
ISLANDS. TROPICAL STORM CONDITIONS ARE EXPECTED OVER PORTIONS OF
PUERTO RICO AND THE U.S. AND BRITISH VIRGIN ISLANDS TODAY.
HURRICANE CONDITIONS ARE EXPECTED OVER PORTIONS OF THE DOMINICAN
REPUBLIC BY FRIDAY...AND OVER PORTIONS OF HAITI FRIDAY OR FRIDAY
NIGHT. TROPICAL STORM CONDITIONS ARE POSSIBLE OVER THE
SOUTHEASTERN BAHAMAS AND THE TURKS AND CAICOS ISLANDS BY LATE
FRIDAY.

RAINFALL...TOTAL RAINFALL ACCUMULATIONS OF 8 TO 12 INCHES...
WITH MAXIMUM AMOUNTS OF 20 INCHES...ARE POSSIBLE OVER HISPANIOLA.
THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES. TOTAL RAIN ACCUMULATIONS OF 2 TO 4 INCHES...WITH MAXIMUM
AMOUNTS OF 10 INCHES OVER HIGHER TERRAIN...ARE POSSIBLE OVER PUERTO
RICO AND THE VIRGIN ISLANDS. TOTAL RAIN ACCUMULATIONS OF 4 TO 8
INCHES ARE POSSIBLE OVER THE NORTHERN WINDWARD ISLANDS AND THE
LEEWARD ISLANDS.

STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS
3 TO 5 FEET ABOVE NORMAL TIDE LEVELS IN AREAS OF ONSHORE WINDS ALONG
THE COAST OF HISPANIOLA. A STORM SURGE WILL RAISE WATER LEVELS BY
AS MUCH AS 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS IN THE NORTHERN
LEEWARD ISLANDS...PUERTO RICO...AND THE U.S. AND BRITISH VIRGIN
ISLANDS. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY
DANGEROUS WAVES.

SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL AFFECT THE
WINDWARD ISLANDS...LEEWARD ISLANDS...VIRGIN ISLANDS...AND PUERTO
RICO DURING THE NEXT COUPLE OF DAYS. PLEASE CONSULT PRODUCTS FROM
YOUR LOCAL WEATHER OFFICE FOR MORE INFORMATION.



Tropical Storm Isaac Satellite image August 22, 2012

Published on August 23, 2012 11:44 AM | Comments

Here is a great picture of Isaac as a tropical storm before crossing in the Caribbean basin:

20120822ISAAC.jpg


UPDATE: US Coast Guard to Close Sea Ports in the US Virgin Islands at 8 PM Tonight; Ferry Operators Adjust Schedules

Published on August 22, 2012 5:16 PM | Comments

Alert / Warning
Transportation - Waterway Disruption or Delay

...This is an ACTUAL WATERWAY DISRUPTION OR DELAY ALERT...

Issued By: VITEMA
Affected Jurisdictions: St. Croix, St. John, St. Thomas, Water Island
Counties

Headline: UPDATE: US Coast Guard to Close Sea Ports in the US Virgin
Islands at 8 PM Tonight; Ferry Operators Adjust Schedules

The US Coast Guard will implement Port Condition ZULU at 8 PM tonight for
the all sea ports in the US VIrgin Islands, officially suspending operations
and closing ports to incoming and outgoing vessel traffic until otherwise
directed by the Captain of the Port.

As a result of the port closure, ferry operators have adjusted schedules:

Departing:

A) Cruz Bay, St. John, hourly with final service at 7 PM

B) Red Hook, St. Thomas hourly until 7 PM with final service at 7:30 PM

C) Charlotte Amalie, St. Thomas: No change in schedule

All intra-island ferries in the U.S. Virgin Islands must cease operations
and be secured at their designated mooring facility when Port Condition ZULU
is in place for their respective port.

Mariners, owners and operators of recreational vessels should follow small
craft advisories from the National Weather Service and take the necessary
measures to safeguard the safety of their vessels, http://www.nhc.noaa.gov
("http://www.nhc.noaa.gov") .

Pleasure craft operators are advised to seek safe harbor. Owners of larger
boats are urged to move their boats to inland marinas where they will be
less vulnerable to breaking free of their moorings or sustaining damage.
Trailerable boats should be pulled from the water and stored in a place
that is not prone to flooding.

Those who are leaving their boats in the water are reminded to secure life
rings, lifejackets and small boats. These items, if not secured properly,
can break free and require valuable search and rescue resources to be
diverted from a real emergency.



CENTER OF ISAAC ABOUT TO MOVE THROUGH THE LEEWARD ISLANDS

Published on August 22, 2012 2:15 PM | Comments

BULLETIN TROPICAL STORM ISAAC INTERMEDIATE ADVISORY NUMBER 6A
NWS NATIONAL HURRICANE CENTER MIAMI FL
AL092012 200 PM AST WED AUG 22 2012

...CENTER OF ISAAC ABOUT TO MOVE THROUGH THE LEEWARD ISLANDS...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...15.8N 60.2W ABOUT 75 MI...120 KM ENE OF DOMINICA ABOUT 95 MI...155 KM ESE OF GUADELOUPE MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...W OR 280 DEGREES AT 21 MPH...33 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR... * MARTINIQUE * DOMINICA * GUADELOUPE AND THE SURROUNDING ISLANDS...AND ST. MARTIN * ST. KITTS...NEVIS...ANTIGUA...BARBUDA...MONTSERRAT...AND ANGUILLA * SABA...ST. EUSTATIUS...AND ST. MAARTEN * BRITISH VIRGIN ISLANDS * PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS

A HURRICANE WATCH IS IN EFFECT FOR... * PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. AND BRITISH VIRGIN ISLANDS * SOUTH COAST OF DOMINICAN REPUBLIC FROM ISLA SAONA WESTWARD TO THE HAITI-DOMINICAN REPUBLIC SOUTHERN BORDER

A TROPICAL STORM WATCH IS IN EFFECT FOR... * NORTH COAST OF DOMINICAN REPUBLIC FROM THE HAITI-DOMINICAN REPUBLIC NORTHERN BORDER EASTWARD TO NORTH OF ISLA SAONA

A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA. A WATCH IS TYPICALLY ISSUED 48 HOURS BEFORE THE ANTICIPATED FIRST OCCURRENCE OF TROPICAL-STORM-FORCE WINDS...CONDITIONS THAT MAKE OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS.

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 HAITI AND CUBA SHOULD MONITOR THE PROGRESS OF ISAAC.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...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.


DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 200 PM AST...1800 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 15.8 NORTH...LONGITUDE 60.2 WEST. ISAAC IS MOVING TOWARD THE WEST NEAR 21 MPH...33 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST TRACK...THE CENTER OF ISAAC SHOULD MOVE THROUGH THE LEEWARD ISLANDS DURING THE NEXT SEVERAL HOURS...PASS NEAR OR SOUTH OF THE VIRGIN ISLANDS AND PUERTO RICO ON THURSDAY...AND APPROACH THE DOMINICAN REPUBLIC THURSDAY NIGHT AND FRIDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 45 MPH...75 KM/H...WITH HIGHER GUSTS. STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND ISAAC COULD BECOME A HURRICANE BY THURSDAY OR THURSDAY NIGHT.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB...29.71 INCHES.


HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE LEEWARD ISLANDS DURING THE NEXT SEVERAL HOURS...MAKING OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS. TROPICAL STORM CONDITIONS ARE EXPECTED OVER PUERTO RICO AND THE U.S. AND BRITISH VIRGIN ISLANDS ON THURSDAY. HURRICANE CONDITIONS ARE POSSIBLE OVER PUERTO RICO...THE U.S. VIRGIN ISLANDS ON THURSDAY...AND OVER THE DOMINICAN REPUBLIC BY LATE THURSDAY.

RAINFALL...TOTAL RAIN ACCUMULATIONS OF 4 TO 8 INCHES ARE POSSIBLE OVER THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS. TOTAL RAIN ACCUMULATIONS OF 1 TO 3 INCHES WITH MAXIMUM AMOUNTS OF 6 INCHES ARE POSSIBLE OVER PUERTO RICO AND THE VIRGIN ISLANDS. TOTAL RAINFALL ACCUMULATIONS OF 8 TO 12 INCHES...WITH MAXIMUM AMOUNTS OF 20 INCHES...ARE POSSIBLE OVER HISPANIOLA. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES.

STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS IN THE NORTHERN LEEWARD ISLANDS...PUERTO RICO...AND THE U.S. AND BRITISH VIRGIN ISLANDS. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY DANGEROUS WAVES.

SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL AFFECT THE WINDWARD AND LEEWARD ISLANDS DURING THE NEXT COUPLE OF DAYS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE FOR MORE INFORMATION.



Tropical Storm Isaac

Published on August 21, 2012 5:15 PM | Comments

Issac is not a tropical storm and forecast to become a hurricane. The Windward and Leeward islands have tropical storm warnings and watches up already. People in those areas should be making rapid preparations for this storm.

TROPICAL STORM ISAAC DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 500 PM AST TUE AUG 21 2012

AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE DEPRESSION REPORTED 44-KT FLIGHT-LEVEL WINDS AT 1000 FT TO THE NORTHEAST OF THE CENTER...AS WELL AS BIAS-CORRECTED SFMR SURFACE WINDS ESTIMATES OF 35 KT. THE MINIMUM CENTRAL PRESSURE WAS NEAR 1005 MB. BASED ON THESE DATA...THE DEPRESSION IS UPGRADED TO TROPICAL STORM ISAAC. DESPITE THE UPGRADE...THE CYCLONE REMAINS SOMEWHAT DISORGANIZED...WITH THE LOW-LEVEL CENTER PARTLY EXPOSED TO THE NORTH OF THE MAIN CONVECTIVE MASS.

THE LOW-LEVEL CENTER HAS NUDGED NORTHWARD DURING THE AFTERNOON...BUT THE LONGER TERM MOTION IS 275/15. ISAAC REMAINS SOUTH OF A DEEP-LAYER SUBTROPICAL RIDGE THAT IS FORECAST TO REMAIN INTACT FOR THE NEXT 72 HR...WHICH SHOULD KEEP THE CYCLONE MOVING GENERALLY WESTWARD AS SHOWN BY THE TIGHTLY CLUSTERED TRACK MODEL GUIDANCE. AFTER THAT...THE GLOBAL MODELS CONTINUE TO FORECAST A SHORTWAVE TROUGH TO DIG SOUTHWARD OVER THE SOUTHEASTERN U.S. AND THE GULF OF MEXICO...WHICH IS EXPECTED TO WEAKEN THE RIDGE ACROSS FLORIDA AND THE BAHAMAS. THIS SHOULD ALLOW THE CYCLONE TO TURN WEST- NORTHWESTWARD AND SLOW DOWN OVER THE NORTH-CENTRAL CARIBBEAN SEA AND THE GREATER ANTILLES. THE GUIDANCE HAS BECOME LESS CONSISTENT SINCE THE PREVIOUS ADVISORY. WHILE THE CENTER OF THE GUIDANCE ENVELOPE HAS CHANGED LITTLE...THE ECMWF HAS SHIFTED WELL TO THE LEFT OF ITS PREVIOUS FORECAST AND NOW CALLS FOR A WESTWARD MOTION AFTER ISAAC PASSES HISPANIOLA. THE GFS ENSEMBLES HAVE ALSO SHIFTED WESTWARD...ALTHOUGH THE ENSEMBLE MEAN STILL LIES NEAR THE FORECAST TRACK. THE NEW TRACK IS NUDGED A LITTLE TO THE NORTH OF THE PREVIOUS TRACK BEFORE 72 HR...AND THEN IS NUDGED A LITTLE TO THE RIGHT THEREAFTER. THE TRACK FORECAST AFTER 72 HR LIES NEAR THE LEFT EDGE OF THE GUIDANCE ENVELOPE...WITH ONLY THE ECMWF WELL TO THE LEFT OF THE CURRENT FORECAST. USERS ARE CAUTIONED THAT FIVE-DAY TRACK ERRORS AVERAGE ABOUT 225 N MI.

ISAAC CONTINUES TO EXPERIENCE SOME LIGHT NORTHEASTERLY VERTICAL WIND SHEAR...AND IT MAY NOT YET HAVE FULLY MIXED OUT THE DRY AIR THAT HAS BEEN AFFECTING IT. THE SHEAR IS FORECAST TO DIMINISH IN 12-24 HR...WHICH SHOULD ALLOW SOME STRENGTHENING. THAT BEING SAID...THE GFDL AND HWRF MODELS HAVE BACKED OFF ON THEIR FORECASTS OF INTENSIFICATION...AND THE SHIPS AND LGEM MODELS ARE ALSO LESS BULLISH. BASED ON THIS...THE NEW INTENSITY FORECAST SHOWS A LITTLE LESS STRENGTHENING THAN THE PREVIOUS ADVISORY. THE INTENSITY FORECAST AFTER 72 HR HAS AGAIN BEEN REDUCED DUE TO THE FORECAST TRACK SHOWING INCREASED LAND INTERACTION WITH HISPANIOLA AND CUBA.



Tropical Depression 9 5 Day Track

Published on August 21, 2012 10:54 AM | Comments



TD 9 forms in the Atlantic, another system close behind

Published on August 21, 2012 10:42 AM | Comments

The NHC is reporting on two potential Caribbean threatening systems, TD 9 and another system behind it:

two_atl8.21.12.gif

Theses systems need to be watched. Currently TD 9 looks like it may track into the Caribbean basin and then along the southern coast of Hispaniola as a hurricane.

From the NHC:

TROPICAL WEATHER OUTLOOK NWS NATIONAL HURRICANE CENTER MIAMI FL 800 AM EDT TUE AUG 21 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON NEWLY FORMED TROPICAL DEPRESSION NINE LOCATED ABOUT 645 MILES EAST OF GUADELOUPE IN THE LESSER ANTILLES.

1. A WELL-DEFINED LOW PRESSURE SYSTEM ASSOCIATED WITH A TROPICAL WAVE IS LOCATED ABOUT 425 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS. SHOWERS AND THUNDERSTORMS CONTINUE TO SHOW SIGNS OF ORGANIZATION... AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT DAY OR TWO. THIS SYSTEM HAS A HIGH CHANCE...60 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT ABOUT 15 MPH.

2. DISORGANIZED SHOWER ACTIVITY ASSOCIATED WITH AN ELONGATED AREA OF LOW PRESSURE...LOCATED OFFSHORE OF THE NORTHEASTERN COAST OF MEXICO...HAS CHANGED LITTLE OVERNIGHT. SOME SLOW DEVELOPMENT IS STILL POSSIBLE BEFORE THE DISTURBANCE MOVES INLAND LATE TODAY OR WEDNESDAY. THIS SYSTEM HAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT DRIFTS WESTWARD.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

PUBLIC ADVISORIES ON TROPICAL DEPRESSION NINE ARE ISSUED UNDER WMO HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4. FORECAST/ADVISORIES ON TROPICAL DEPRESSION NINE ARE ISSUED UNDER WMO HEADER WTNT24 KNHC AND UNDER AWIPS HEADER MIATCMAT4.