Hurricane Irene A Potential Long Range Threat To The Region

000

WTNT34 KNHC 230258
TCPAT4

BULLETIN
HURRICANE IRENE ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
1100 PM AST MON AUG 22 2011....

AT 1100 PM AST...0300 UTC...THE CENTER OF HURRICANE IRENE WAS

LOCATED BY AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT NEAR
LATITUDE 19.9 NORTH...LONGITUDE 69.2 WEST.

IRENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 12 MPH...19 KM/H...AND THIS MOTION IS EXPECTED TO CONTINUE THROUGH TUESDAY FOLLOWED BY A TURN TOWARD THE NORTHWEST TUESDAY NIGHT AND WEDNESDAY. ON THE FORECAST TRACK...THE CORE OF IRENE WILL MOVE JUST TO THE NORTH OF THE DOMINICAN REPUBLIC AND HAITI TONIGHT...NEAR OR OVER THE TURKS AND CAICOS ISLANDS AND THE SOUTHEASTERN BAHAMAS ON TUESDAY...AND NEAR THE CENTRAL BAHAMAS EARLY WEDNESDAY.

DATA FROM THE HURRICANE HUNTER AIRCRAFT INDICATE THAT MAXIMUM
SUSTAINED WINDS REMAIN NEAR 100 MPH...160 KM/H...WITH HIGHER
GUSTS. IRENE IS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON
SCALE. ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 48
HOURS...AND IRENE COULD BECOME A MAJOR HURRICANE ON TUESDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 185
MILES...295 KM.

THE MINIMUM CENTRAL PRESSURE BASED ON DATA FROM THE HURRICANE HUNTER
AIRCRAFT IS 980 MB...28.94 INCHES.

FXUS61 KCAR 230151 AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
951 PM EDT MON AUG 22 2011....

......LONG TERM /THURSDAY NIGHT THROUGH MONDAY

FRIDAY A FRONT SHOULD BE OFF TO THE EAST AND HIGH PRESSURE WILL BE
BUILDING INTO THE AREA. EXPECT MOSTLY SUNNY DAYS FOR FRIDAY AND
SATURDAY WITH HIGHS IN THE 70`S FOR BOTH. A FRONT THEN APPROACHES
ON SATURDAY NIGHT AND THAT COULD KICK OFF A FEW SHOWERS FOR
SATURDAY NIGHT INTO SUNDAY. THE MAIN FEATURE NOW ON THE TABLE FOR
THE LONG RANGE IS WHERE WILL IRENE TRACK AND WILL IT IMPACT US.
RIGHT NOW FORECAST MODELS SHOW THAT IRENE WILL TRACK UP THE EAST
COAST AND COME ACROSS MAINE. IT IS WAY TOO FAR IN ADVANCE TO NAIL
DOWN A TRACK AT THIS POINT OR MAKE HUGE CHANGES IN THE FORECAST. STUCK
MAINLY WITH GMOS FOR THE ENTIRE PERIOD UNTIL SUNDAY NIGHT. THE
TRACK OF IRENE IS STILL VERY UNCERTAIN. RIGHT NOW HAVE TAKEN A
MODEL BLEND AND ADJUSTED AS NEEDED FOR SUNDAY NIGHT THROUGH
MONDAY. THE FORECAST IN FUTURE UPDATES MIGHT HAVE MAJOR CHANGES IN
REGARDS TO THIS TIME PERIOD.

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
240 PM EDT MON AUG 22 2011
VALID 12Z THU AUG 25 2011 - 12Z MON AUG 29 2011

...HURRICANE IRENE THREATENING THE EAST COAST LATE THIS WEEK/THIS
WEEKEND...

GLOBAL GUIDANCE WITHIN THE MAIN BAND OF THE WESTERLIES IS IN GOOD
AGREEMENT...WITH A PROGRESSIVE FLOW ANTICIPATED OVER THE NORTHERN
TIER OF THE COUNTRY AND A BREAK IN THE SUBTROPICAL RIDGE NEAR THE
SOUTHEAST COAST. THE GUIDANCE MOST SIMILAR TO THE MOST RECENT
NATIONAL HURRICANE CENTER /NHC/ FORECAST FOR HURRICANE IRENE WAS
THE 00Z CANADIAN. AS IT IS THE LARGEST SYSTEM ON THE MAP
PRESSURE-WISE...THIS LED TO A COMPROMISE OF THE 00Z CANADIAN/00Z
GEFS MEAN/00Z ECMWF ENSEMBLE MEAN FOR THE MORNING PRESSURES TO
MAINTAIN CONSISTENCY WITH NHC...WITH SOME INPUT FROM THE 00Z
ECMWF/06Z GFS ACROSS THE NORTHERN PLAINS WHERE THEY WERE SLIGHTLY
BETTER SUPPORTED BY THE ENSEMBLE MEAN SOLUTIONS. IRENES PLACEMENT
ON THE PROGS ACCELERATED 12 HOURS QUICKER PER THE 17Z COORDINATION
CALL WITH NHC TO ACCOUNT FOR ACCELERATION SEEN WITHIN THE 12Z RUN
OF THE GFS.

FOR IRENE AND THE EAST COAST...THE GUIDANCE HAS SHIFTED MORE TO
THE EAST WHICH COULD LEAD TO MORE TRENDING TO THE EAST/OFFSHORE IN
NHC FORECASTS LATER TODAY. ALTHOUGH INTERACTIONS WITH A COUPLE
SHORTWAVES MOVING THROUGH THE NORTHERN TIER OF THE COUNTRY
COMPLICATE THE FORECAST LATER IN THE MEDIUM RANGE PERIOD AS IRENE
PASSES NEAR NEW ENGLAND...IRENE SHOULD ROUND THE WESTERN PERIPHERY
OF THE SUBTROPICAL RIDGE ACROSS THE WESTERN SUBTROPICAL ATLANTIC
ALONG A PARABOLIC TRACK...WITH THE OUTER BANKS OF NORTH CAROLINA
AND CAPE COD MOST AT RISK AT THIS TIME. PER THE COORDINATED TRACK
WITH NHC AT 17Z...MODERATE TO HEAVY RAINS SHOULD INITIALLY FORM
ALONG A DEVELOPING COASTAL FRONT NEAR THE SOUTHEAST COAST WHICH
BECOMES REINFORCED BY A FRONT DROPPING IN FROM THE WESTERLIES.
HEAVY RAINS SHOULD SPREAD UP THE COAST OF THE MID-ATLANTIC AND NEW
ENGLAND STATES WITH TIME. THE CYCLONE IS THEN EXPECTED TO MOVE
ALONG THE COAST OF THE CAROLINAS OFFSHORE THE NORTHEAST JUST
INSIDE THE 40N/70W BENCHMARK SUNDAY. IF THE NHC TRACK SHIFTS
FARTHER TO THE RIGHT/EAST...THE THREAT FOR HEAVY RAINS
ACROSS THESOUTHEAST/EAST COAST COULD LESSEN FURTHER. SEE THE LATEST
REASONING/TRACK FROM THE NHC REGARDING HURRICANE IRENE.

ROTH