Irene strengthens over Puerto Rico... becoming the first hurricane of the 2011 Atlantic season
Posted by
Chris in Tampa on 8/22/2011, 5:02 am
HURRICANE IRENE ADVISORY NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
500 AM AST MON AUG 22 2011
...IRENE STRENGTHENS OVER PUERTO RICO...BECOMING THE FIRST HURRICANE
OF THE 2011 ATLANTIC SEASON...
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...18.4N 66.4W
ABOUT 25 MI...40 KM W OF SAN JUAN PUERTO RICO
ABOUT 125 MI...200 KM E OF PUNTA CANA DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...
A HURRICANE WATCH HAS BEEN ISSUED FOR THE NORTH COAST OF HAITI
FROM LE MOLE ST. NICHOLAS EASTWARD TO THE DOMINICAN REPUBLIC BORDER.
THE HURRICANE WATCH HAS BEEN DISCONTINUED FOR THE U.S. VIRGIN
ISLANDS.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT...
A HURRICANE WARNING IS IN EFFECT FOR...
* PUERTO RICO...VIEQUES...AND CULEBRA
* NORTH COAST OF THE DOMINICAN REPUBLIC FROM THE HAITI BORDER
EASTWARD TO CABO ENGANO
A HURRICANE WATCH IS IN EFFECT FOR...
* NORTH COAST OF HAITI FROM LE MOLE ST. NICHOLAS EASTWARD TO THE
DOMINICAN REPUBLIC BORDER
* CENTRAL BAHAMAS
A TROPICAL STORM WARNING IS IN EFFECT FOR...
* U.S. VIRGIN ISLANDS
* BRITISH VIRGIN ISLANDS
* SOUTH COAST OF THE DOMINICAN REPUBLIC FROM SOUTH OF CABO ENGANO
WESTWARD TO THE HAITI BORDER
* ALL OF HAITI
* SOUTHEASTERN BAHAMAS AND THE TURKS AND CAICOS ISLANDS
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.
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 500 AM AST...0900 UTC...DATA FROM THE SAN JUAN FAA DOPPLER
WEATHER RADAR INDICATE THAT THE CENTER OF HURRICANE IRENE WAS
LOCATED ALONG THE NORTH COAST OF PUERTO RICO NEAR LATITUDE 18.4
NORTH...LONGITUDE 66.4 WEST. IRENE IS MOVING TOWARD THE
WEST-NORTHWEST NEAR 12 MPH...19 KM/H. THIS GENERAL MOTION IS
EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST
TRACK THE CENTER OF IRENE WILL MOVE OFF THE NORTH COAST OF PUERTO
RICO THIS MORNING...AND MOVE NEAR OR OVER THE NORTHERN COASTAL
REGIONS OF THE DOMINICAN REPUBLIC THIS AFTERNOON AND TONIGHT.
MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 75 MPH...120
KM/H...WITH HIGHER GUSTS. IRENE IS A CATEGORY ONE HURRICANE ON
THE SAFFIR-SIMPSON HURRICANE WIND SCALE. SOME STRENGTHENING IS
FORECAST DURING THE NEXT 48 HOURS.
HURRICANE-FORCE WINDS EXTEND OUTWARD UP TO 15 MILES...30 KM...FROM
THE CENTER...AND TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO
150 MILES...240 KM...MAINLY NORTHWEST AND NORTHEAST OF THE CENTER.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB...29.15 INCHES.
HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE OCCURRING IN THE VIRGIN
ISLANDS...EASTERN PUERTO RICO...CULEBRA AND VIEQUES...AND WILL
CONTINUE TO SPREAD ACROSS PUERTO RICO THIS MORNING. TROPICAL STORM
CONDITIONS WILL REACH THE DOMINICAN REPUBLIC BY THIS AFTERNOON.
HURRICANE CONDITIONS ARE EXPECTED OVER PUERTO RICO...VIEQUES...AND
CULEBRA THIS MORNING...AND OVER THE NORTHERN PORTIONS OF THE
DOMINICAN REPUBLIC MONDAY AFTERNOON AND EVENING. THE HIGHEST WINDS
ARE LIKELY TO OCCUR OVER AREAS OF ELEVATED TERRAIN. TROPICAL STORM
CONDITIONS ARE EXPECTED TO REACH THE SOUTHEASTERN BAHAMAS AND THE
TURKS AND CAICOS ISLANDS TUESDAY...AND ARE POSSIBLE IN THE CENTRAL
BAHAMAS BY LATE TUESDAY. HURRICANE CONDITIONS ARE POSSIBLE IN THE
CENTRAL BAHAMAS BY TUESDAY NIGHT.
RAINFALL...IRENE IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS
OF 5 TO 10 INCHES ACROSS PUERTO RICO...THE VIRGIN ISLANDS...THE
DOMINICAN REPUBLIC...HAITI...THE SOUTHEASTERN BAHAMAS AND THE TURKS
AND CAICOS ISLANDS. ISOLATED MAXIMUM AMOUNTS OF UP TO 20 INCHES
ARE POSSIBLE. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH
FLOODS AND MUD SLIDES IN AREAS OF STEEP TERRAIN.
STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 2
TO 4 FEET ABOVE NORMAL TIDE LEVELS ALONG THE ENTIRE COAST OF THE
DOMINICAN REPUBLIC. A STORM SURGE OF 1 TO 3 FEET ABOVE NORMAL TIDE
LEVELS IS EXPECTED ALONG THE COAST OF PUERTO RICO...AS WELL AS IN
THE REMAINDER OF THE TROPICAL STORM WARNING AREA. NEAR THE COAST...
THE SURGE WILL BE ACCOMPANIED BY LARGE AND DANGEROUS WAVES.
NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORIES...700 AM AST AND 900 AM AST.
NEXT COMPLETE ADVISORY...1100 AM AST.
$$
FORECASTER STEWART
--------------------------------------------------
HURRICANE IRENE DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
500 AM AST MON AUG 22 2011
IRENE HAS BECOME MUCH BETTER ORGANIZED DURING THE PAST 6 HOURS
DESPITE ITS INTERACTION WITH THE MOUNTAINOUS TERRAIN OF PUERTO
RICO...AND A RAGGED EYE HAS BECOME APPARENT IN IMAGERY FROM THE FAA
TERMINAL DOPPLER WEATHER RADAR. ALSO...LARGE PATCHES OF DOPPLER
VELOCITY VALUES AS HIGH AS 75-82 KT AT 1000-1500 FT AND 85-91 KT
AT 2000-3000 FT HAVE BEEN INDICATED NORTHWEST AND NORTHEAST OF THE
CENTER OVER WATER FOR THE PAST 2 HOURS...WHICH EQUATES TO AT LEAST
65-KT SURFACE WINDS. SOME DOPPLER VELOCITIES AS HIGH AS 72 KT HAVE
ALSO BEEN DETECTED AT 500-600 FT OVER WATER. AS A RESULT OF THESE
DATA...IRENE HAS BEEN UPGRADED TO THE FIRST HURRICANE OF THE 2011
ATLANTIC HURRICANE SEASON.
TRENDING THROUGH ALL OF THE WOBBLES IN THE TRACK OVER THE PAST 6
HOURS YIELDS AN AVERAGE MOTION OF ABOUT 290/10 KT. UPPER-AIR DATA
AT 00Z INDICATE 500 MB HEIGHTS HAVE NOT CHANGED AT BERMUDA IN THE
PAST 24 HOURS...WHICH SUGGESTS THAT THE SUBTROPICAL RIDGE TO THE
NORTH OF IRENE REMAINS QUITE STRONG. THE RIDGE IS EXPECTED TO
CHANGE LITTLE FOR THE NEXT 48 HOURS OR SO...WHICH WOULD ACT TO KEEP
IRENE MOVING IN A GENERAL WEST-NORTHWESTWARD DIRECTION OFF THE
NORTH COAST OF PUERTO RICO THIS MORNING AND JUST SKIRTING THE
NORTHERN COAST OF HISPANIOLA LATER TODAY AND ON TUESDAY. AFTER
THAT...THE GLOBAL MODELS DIVERGE ON THE SPECIFICS OF HOW LARGE A
BREAK OR WEAKNESS IN THE SUBTROPICAL RIDGE DEVELOPS OVER FLORIDA
AND THE SOUTHEASTERN U.S. AT 72 HOUR AND BEYOND...WHICH WILL ALLOW
IRENE TO MOVE NORTHWESTWARD. THE ECMWF...NOGAPS...AND GFDN MODELS
ARE THE RIGHTMOST OF THE NHC MODEL GUIDANCE SUITE AND KEEP IRENE
WELL EAST OF FLORIDA...WHEREAS THE UKMET AND THE GFDL MODELS ARE
THE LEFTMOST OF THE MODELS AND TAKE IRENE NEAR THE WEST COAST OF
FLORIDA. THE GFS AND THE REST OF THE NHC MODEL GUIDANCE IS TIGHTLY
PACKED BETWEEN THESE TWO EXTREMES AND TAKE IRENE THROUGH THE
BAHAMAS AND JUST OFF THE FLORIDA EAST COAST. WHAT IS NOTEWORTHY IS
THAT ALL OF THE GLOBAL AND REGIONAL MODELS AGREE THAT THE OUTFLOW
OF IRENE WILL CONVERGE WITH WESTERLY TO NORTHWESTERLY UPPER-LEVEL
MID-LATITUDE FLOW OVER THE MID-ATLANTIC STATES BY 96 HOURS AND
BEYOND. THIS UPPER-LEVEL MASS CONFLUENCE COULD MAINTAIN THE MID- TO
LOW-LEVEL RIDGE A LITTLE BIT STRONGER AND LONGER THAN WHAT NOGAPS
AND THE ECMWF ARE FORECASTING...WHICH WOULD IN TURN KEEP IRENE A
LITTLE CLOSER TO THE FLORIDA EAST COAST. AS A RESULT...THE OFFICIAL
FORECAST TRACK WAS ONLY SHIFTED SLIGHTLY TO THE EAST OF THE
PREVIOUS TRACK AND IS NEAR THE CONSENSUS MODELS TVCN AND TVCA.
IT NOW APPEARS THAT IRENE WILL NOT INTERACT WITH HISPANIOLA AS MUCH
OR AS LONG AS PREVIOUSLY EXPECTED. THIS WILL ALSO RESULT IN MORE
STRENGTHENING THAN PREVIOUSLY EXPECTED. IRENE IS FORECAST BY ALL OF
THE MODELS TO HAVE A VERY IMPRESSIVE OUTFLOW PATTERN THROUGHOUT THE
FORECAST PERIOD...INCLUDING A LARGE UPPER-LEVEL TROUGH/LOW ABOUT
1200 NMI EAST OF THE CYCLONE ACTING AS A MASS SINK. WITH IRENE ALSO
EXPECTED TO BE OVER SSTS NEAR 30C AFTER 48 HOURS...SIGNIFICANT
STRENGTHENING COULD OCCUR. HOWEVER...THE OFFICIAL INTENSITY WILL
REMAIN ON THE CONSERVATIVE SIDE DUE TO THE UNCERTAINTY IN HOW MUCH
IRENE WILL INTERACT WITH THE MOUNTAINOUS TERRAIN OF HISPANIOLA FOR
THE NEXT 24-36 HOURS. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF
THE SHIPS/LGEM MODELS AND THE HWRF/GFDL MODELS. HOWEVER...GIVEN THE
IMPRESSIVE UPPER-LEVEL FLOW PATTERN EXPECTED ACROSS IRENE...IT
WOULD NOT SURPRISE ME IF THIS CYCLONE BECAME A MAJOR HURRICANE AT
SOME TIME DURING ITS LIFETIME LIKE THE GFDL AND HWRF MODELS ARE
FORECASTING.
IT IS IMPORTANT NOT TO FOCUS ON THE EXACT FORECAST TRACK...
ESPECIALLY AT DAYS 4 TO 5...SINCE THE MOST RECENT 5-YEAR AVERAGE
ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES...
RESPECTIVELY.
FORECAST POSITIONS AND MAX WINDS
INIT 22/0900Z 18.4N 66.4W 65 KT 75 MPH
12H 22/1800Z 18.9N 68.2W 70 KT 80 MPH
24H 23/0600Z 19.7N 70.5W 70 KT 80 MPH...INLAND
36H 23/1800Z 20.4N 72.4W 70 KT 80 MPH...OVER WATER
48H 24/0600Z 21.3N 74.1W 75 KT 85 MPH
72H 25/0600Z 24.0N 77.1W 80 KT 90 MPH
96H 26/0600Z 27.0N 79.5W 85 KT 100 MPH
120H 27/0600Z 30.9N 81.5W 95 KT 110 MPH
$$
FORECASTER STEWART
|
275
In this thread:
Irene strengthens over Puerto Rico... becoming the first hurricane of the 2011 Atlantic season - Chris in Tampa, 8/22/2011, 5:02 am Post A Reply
This thread has been archived and can no longer receive replies.