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It took a while - but after meandering around a bit, Ophelia is a hurricane. It is forecast to head north and away from the Caribbean - we'll see! This could be an issue for Bermuda however...
HURRICANE OPHELIA DISCUSSION NUMBER 29
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011
500 PM AST THU SEP 29 2011
SATELLITE IMAGES AND MICROWAVE DATA INDICATE THAT THE CLOUD PATTERN
HAS CONTINUED TO ACQUIRE ORGANIZATION. THERE IS A CYCLONICALLY
CURVED CONVECTIVE BAND WRAPPING AROUND THE CENTER AND THE
UPPER-LEVEL OUTFLOW HAS EXPANDED IN ALL QUADRANTS. THERE HAS BEEN
AN EYE FEATURE INTERMITTENTLY APPEARING ON VISIBLE IMAGES...BUT
THERE IS DEFINITELY A DISTINCT ONE AT THE MID-LEVELS ON EARLIER
MICROWAVE DATA. T-NUMBERS FROM TAFB AND SAB HAVE INCREASED TO 4.0
ON THE DVORAK SCALE AND ON THIS BASIS...OPHELIA HAS BEEN UPGRADED
TO HURRICANE STATUS...THE FOURTH OF THE 2011 SEASON.
OPHELIA HAS KICKED OUT THE SHEAR AND GLOBAL MODELS INSIST ON KEEPING
AN UPPER-LEVEL RIDGE OVER THE CYCLONE. THIS PATTERN SHOULD ALLOW
SOME ADDITIONAL STRENGTHENING DURING THE NEXT DAY OR SO. THE
OFFICIAL FORECAST CONTINUE TO BE VERY SIMILAR TO THE STATISTICAL
LGEM...ALTHOUGH SOME MODELS FORECAST A STRONGER HURRICANE.
BEYOND 72 HOURS THE SHEAR IS FORECAST TO INCREASE SIGNIFICANTLY...
AND THE SEA SURFACE TEMPERATURES WILL DECREASE. THIS SHOULD RESULT
IN WEAKENING...AND MOST LIKELY OPHELIA WILL BECOME POST-TROPICAL BY
96 HOURS OR SOONER.
OPHELIA HAS BEEN MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT
8 KNOTS. THERE HAS BEEN NO CHANGE IN THE STEERING TO REPORT. THE
OFFICIAL FORECAST REMAINS UNCHANGED AND CONTINUES IN THE MIDDLE OF
THE GUIDANCE ENVELOPE IN BETWEEN THE GFS AND THE ECMWF FOR THE NEXT
2 TO 3 DAYS. OPHELIA SHOULD GRADUALLY TURN TO THE NORTH BY FRIDAY
AND THEN RECURVE NEAR THE LATITUDE OF BERMUDA IN ABOUT 48 HOURS.
THE WESTERN EDGE OF THE GUIDANCE ENVELOPE BARELY REACHES BERMUDA
AT THIS TIME.
Remnants of Ophelia, Tropical Storm Philippe UPDATE
This is an update - as Ophelia looks like it may in fact become a named storm again and could produce heavy rains for the Leeward islands:
1. A LOW PRESSURE SYSTEM...THE REMNANTS OF OPHELIA...CENTERED A COUPLE
OF HUNDRED MILES EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS...
IS PRODUCING A LARGE AREA OF SHOWERS AND THUNDERSTORMS. SURFACE
AND SATELLITE OBSERVATIONS INDICATE THAT THE SYSTEM HAS A BROAD
CIRCULATION...AND UPPER-LEVEL WINDS APPEAR SOMEWHAT CONDUCIVE FOR
ADDITIONAL REDEVELOPMENT AS THE LOW MOVES SLOWLY NORTHWESTWARD
DURING THE NEXT DAY OR TWO. THIS SYSTEM HAS A HIGH CHANCE...80
PERCENT...OF REGENERATING INTO A TROPICAL CYCLONE DURING THE NEXT
48 HOURS. LOCALLY HEAVY RAINS ARE POSSIBLE OVER PORTIONS OF THE
NORTHERN LEEWARD ISLANDS THROUGH WEDNESDAY.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
The remnants of Tropical Storm Ophelia are still hanging around north of the Leeward Islands, and Tropical Storm Philippe is out in the Atlantic meandering northward. Neither system looks at this point to be a risk to the Caribbean region.
Tropical Storm Ophelia has formed in the Atlantic and looks like it will be another storm that tracks through the Leeward Islands. It is not forecast to become a hurricane any time soon, but you should keep and eye on it if you are in the region:
TROPICAL STORM OPHELIA DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011
500 AM EDT WED SEP 21 2011
CURVED CONVECTIVE BANDS OVER THE NORTHERN AND SOUTHERN PORTIONS OF
THE LARGE CIRCULATION HAVE BECOME A LITTLE BETTER DEFINED THIS
MORNING...HOWEVER THERE IS STILL A LACK OF DEEP CONVECTION NEAR
THE CENTER OF THE TROPICAL STORM. THE INITIAL INTENSITY OF THE
CYCLONE HAS BEEN INCREASED TO 40 KT...BASED ON DATA FROM A SHIP
LOCATED TO THE NORTH OF THE CENTER AND AN EARLIER ASCAT PASS.
THE UPPER-LEVEL WIND PATTERN AHEAD OF OPHELIA DOES NOT FAVOR
SIGNIFICANT STRENGTHENING. MODERATE SOUTHWESTERLY SHEAR CURRENTLY
OVER THE CYCLONE IS EXPECTED TO BECOME MORE WESTERLY AND INCREASE
IN A FEW DAYS AS AN UPPER-LEVEL LOW FORMS NORTH OF PUERTO RICO.
MOST OF THE INTENSITY GUIDANCE AGREES WITH THIS SCENARIO AND CALLS
FOR ONLY A LITTLE ADDITIONAL STRENGTHENING. THE NHC FORECAST IS IN
GOOD AGREEMENT WITH THE SHIPS/LGEM GUIDANCE AND IS VERY SIMILAR TO
THE PREVIOUS ADVISORY.
THE INITIAL MOTION ESTIMATE REMAINS RATHER UNCERTAIN...HOWEVER
IT APPEARS THAT OPHELIA IS MOVING A LITTLE FASTER THAN BEFORE. THE
TRACK FORECAST REASONING IS UNCHANGED FROM THE PREVIOUS NHC
ADVISORY. OPHELIA IS EXPECTED TO MOVE WESTWARD DURING THE NEXT
COUPLE OF DAYS TO THE SOUTH OF THE SUBTROPICAL RIDGE. AFTER 72
HOURS...THE WESTERN PORTION OF THE RIDGE IS EXPECTED TO WEAKEN AS A
LARGE MID/UPPER-LEVEL LOW DEVELOPS OVER THE EASTERN UNITED STATES.
THIS SHOULD RESULT IN THE CYCLONE TURNING TOWARD THE WEST-NORTHWEST
WITH SOME REDUCTION IN FORWARD SPEED. THE UPDATED NHC FORECAST
LIES BETWEEN THE TYPICALLY RELIABLE GFS AND ECMWF MODELS...AND IS
VERY CLOSE TO THE PREVIOUS ADVISORY.
The only good news about this storm is that it is not a hurricane - it is looking like it will track directly over the Virgin Islands, which will likely see a lot of rain and winds of about 40 to 50 MPH:
TROPICAL STORM MARIA DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011
500 AM AST FRI SEP 09 2011
THERE HAS BEEN AN INCREASE IN THE CONVECTION DURING THE PAST SEVERAL
HOURS BUT SATELLITE INTENSITY ESTIMATES HAVE NOT CHANGED. SURFACE
PRESSURES ARE FALLING...AS INDICATED BY BUOY 41101 WHICH RECENTLY
REPORTED A MINIMUM PRESSURE OF 1003.7 MB. THE INITIAL INTENSITY IS
KEPT AT 35 KNOTS AT THIS TIME...AND A RECONNAISSANCE PLANE WILL
CHECK MARIA AROUND 1200 UTC. THE UPPER-LEVEL WIND ENVIRONMENT IS
NOT AS HOSTILE AS IT WAS 12 TO 24 HOURS AGO...AND THE INTENSITY
GUIDANCE SHOWS SOME SLIGHT STRENGTHENING AS THE CYCLONE MOVES
ACROSS THE EXTREME NORTHEASTERN CARIBBEAN SEA...AND IT IS SOMEWHAT
MORE AGGRESSIVE BY THE END OF THE FORECAST PERIOD. THE NHC FORECAST
FOLLOWS SUCH GUIDANCE.
MARIA IS MOVING TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 17
KNOTS. THE LATEST TRACK GUIDANCE HAS SHIFTED TO THE RIGHT AS GLOBAL
MODELS NOW FORECAST A WEAKER SUBTROPICAL RIDGE TO THE NORTH OF THE
CYCLONE. ON THAT BASIS...THE OFFICIAL FORECAST HAS ALSO BEEN
SHIFTED TO THE NORTH BUT IT IS ON THE SOUTHERN EDGE OF THE NEW
GUIDANCE ENVELOPE IN CASE MODELS SHIFT BACK TO THE SOUTH IN THE
NEXT CYCLE. GIVEN THE TRACK AND INTENSITY FORECAST...A TROPICAL
STORM WARNING HAS BEEN ISSUED FOR A LARGE PORTION OF THE
NORTHEASTERN CARIBBEAN ISLANDS.
Tropical Storm Maria is the latest in a fast and furious September so far for named storms. Katia is now an Atlantic hurricane and not a threat to the region, and Nate is a Gulf of Mexico/Central America storm - but Maria, although not forecast to become a hurricane in the Caribbean, looks to be tracking right over the Leeward Islands. It is packing 50 mph winds and plenty of rain, so while it shouldn't be a disastrous storm as currently forecast, it can certainly ruin your vacation and trigger local flooding and heavy surf in the next several days.
TROPICAL STORM MARIA DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011
500 AM AST THU SEP 08 2011
MARIA CURRENTLY HAS A RATHER DISORGANIZED APPEARANCE ON SATELLITE
IMAGES...AND CONSISTS PRIMARILY OF A RATHER SHAPELESS CLUSTER OF
DEEP CONVECTION WITH A FEW THUNDERSTORMS TO THE WEST-SOUTHWEST OF
THE CLUSTER. THERE IS LITTLE...IF ANY...EVIDENCE OF BANDING
FEATURES. AN ASCAT PASS FROM SEVERAL HOURS AGO INDICATED THAT THE
MAXIMUM WINDS REMAIN NEAR 45 KT. HOWEVER...DATA FROM THIS PASS ALSO
CAST SOME DOUBT AS TO WHETHER THE SYSTEM HAS A CLOSED CIRCULATION
AT THIS TIME. VISIBLE IMAGERY AND AN AIRCRAFT MISSION LATER TODAY
SHOULD GIVE MORE INFORMATION ON THE STATUS OF MARIA.
NO CHANGE IS MADE TO THE INTENSITY FORECAST. AN UPPER-LEVEL LOW OR
TROUGH TO THE NORTHWEST OF THE STORM HAS BEEN IMPARTING ABOUT 20 KT
OF SOUTH-SOUTHWESTERLY SHEAR OVER THE TROPICAL CYCLONE...AND
INHIBITING STRENGTHENING. GLOBAL MODELS INDICATE THAT THIS
LOW/TROUGH WILL MOVE MORE OR LESS IN TANDEM WITH MARIA THROUGH
ABOUT 72 HOURS...AND CONTINUE TO PRODUCE SIGNIFICANT SHEAR ON THE
SYSTEM. THE OFFICIAL FORECAST SHOWS NO STRENGTHENING THROUGH 72
HOURS FOLLOWED BY SOME INCREASE IN INTENSITY AS THE IMPACT OF THE
AFOREMENTIONED UPPER-LEVEL LOW IS EXPECTED TO LESSEN. THE NHC WIND
SPEED FORECAST IS ROUGHLY BETWEEN THE LATEST LGEM GUIDANCE AND THE
INTENSITY MODEL CONSENSUS.
THE CENTER IS QUITE DIFFICULT TO FIND...BUT IT IS PRESUMED THAT
MARIA HAS BEEN MAINTAINING A MOTION OF 275/20. A CONTINUED WESTWARD
MOTION IS LIKELY FOR ANOTHER DAY OR SO AS THE STORM MOVES ON THE
SOUTHERN SIDE OF A SUBTROPICAL RIDGE. SOME DECELERATION IS
PREDICTED AS THE RIDGE WEAKENS A LITTLE WITH TIME. IN 48 TO 72
HOURS...MARIA SHOULD BE NEARING A WEAKNESS IN THE RIDGE AND TURN
WEST-NORTHWESTWARD. AS USUAL...THERE IS A FAIR AMOUNT OF
UNCERTAINTY IN THE TRACK 4 TO 5 DAYS FROM NOW. A BROAD 500 MB
TROUGH...MOVING OFF THE U.S EAST COAST...IS SHOWN BY THE GLOBAL
MODELS TO WEAKEN THE RIDGE ENOUGH TO CAUSE MARIA TO TURN
NORTHWESTWARD BY 96 HOURS. IF THE TROUGH TURNS OUT TO BE WEAKER
THAN CURRENTLY PREDICTED...IT COULD DELAY THE NORTHWESTWARD TURN.
THE OFFICIAL FORECAST IS VERY CLOSE TO THE PREVIOUS ONE AND ROUGHLY
IN THE MIDDLE OF THE TRACK GUIDANCE ENVELOPE...BRACKETED BY THE
U.K. MET OFFICE MODEL ON THE LEFT AND BY THE GFS AND HWRF MODELS ON
THE RIGHT.
The forecast remains mixed and unclear, but it should cause rough surf conditions for many Caribbean Islands:
HURRICANE KATIA DISCUSSION NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 AM AST FRI SEP 02 2011
THE CONVECTIVE DEPICTION OF KATIA HAS IMPROVED THIS MORNING AS BOTH
MICROWAVE IMAGERY FROM SSMIS AND CONVENTIONAL VISIBLE SATELLITE
IMAGERY INDICATE THAT AN EYE MAY BE FORMING. BECAUSE OF THE
IMPROVED STRUCTURE...BOTH TAFB AND SAB DVORAK CLASSIFICATIONS CAME
IN AT A 4.0...OR 65 KT...AS DID A 1053Z CIMSS AMSU INTENSITY
ESTIMATE. THUS KATIA HAS REGAINED HURRICANE STATUS.
THE HURRICANE IS MOVING TOWARD THE WEST-NORTHWEST AT ABOUT 12
KT...AS IT IS BEING ADVECTED AROUND THE SOUTHWEST PERIPHERY OF A
DEEP-LAYER RIDGE. KATIA SHOULD MOVE TOWARD THE WEST-NORTHWEST OR
NORTHWEST FOR THE NEXT FEW DAYS AT A SLIGHTLY SLOWER RATE OF SPEED.
ALL OF THE RELIABLE GUIDANCE...WITH THE EXCEPTION OF THE UKMET WHICH
HAS A MUCH MORE EQUATORWARD SOLUTION DUE TO A SHORT-WAVE TROUGH OFF
OF THE U.S. EAST COAST LIFTING OUT TO THE NORTHEAST MORE QUICKLY...
IS IN EXCELLENT AGREEMENT. THE TRACK FORECAST IS VERY SIMILAR TO
THE PREVIOUS ADVISORY AND THE CONSENSUS OF THE GLOBAL AND HURRICANE
MODELS LESS THE UKMET MODEL.
DESPITE BECOMING A HURRICANE AGAIN...KATIA FACES A RELATIVELY
HOSTILE ENVIRONMENT WITH SOUTHWEST VERTICAL SHEAR OF 15-20 KT
SUGGESTED FOR THE NEXT DAY OR TWO. BEYOND 48 HOURS...THE SHEAR
FROM THE GLOBAL MODELS IS ANTICIPATED TO DECREASE...BUT THE
THERMODYNAMICS MAY NOT BE IDEAL WITH LOW HUMIDITIES AND A MORE
STABLE ENVIRONMENT ANTICIPATED. SOME OF THE UPPER-LEVEL
TEMPERATURE INCREASES ANALYZED IN THE SHIPS/LGEM STATISTICAL
MODELS...HOWEVER...MAY BE SPURIOUS...AS THE STRONGER VORTEX FROM
THE GFS MAY BE THE CAUSE OF THESE VALUES RATHER THAN THE
ENVIRONMENT. THUS THE SHIPS/LGEM GUIDANCE MAY BE TOO LOW AT DAYS
THREE TO FIVE. THE INTENSITY PREDICTION IS SLIGHTLY LOWER THAN A
SHIPS/LGEM/HWRF BLEND BUT HIGHER THAN THE PREVIOUS ADVISORY DURING
THE NEXT TWO DAYS.
Tropical Storm Katia is out in the Atlantic. Most models have it becoming a major hurricane, but tracking to the north of the Caribbean Sea. It is very far off to tell, but it could possible be something for Bermuda and/or the Bahamas to worry about. Again, this is why we constantly push Trip Insurance on this website - if you don't have insurance before a storm is named, it won't cover you - and the season is looking active as we come up to the peak hurricane month of September. If you are traveling to the region for any reason this coming month, make sure you get your insurance NOW.
Katia looks like it could be another east coast storm - but I will be gone from NJ before it gets here!
TROPICAL STORM KATIA DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
500 AM AST TUE AUG 30 2011
THE CONVECTIVE PATTERN OF THE CYCLONE HAS IMPROVED OVERNIGHT...WITH
A LARGE AREA OF COLD CLOUD TOPS NOW SITUATED TO THE WEST AND
SOUTHWEST OF THE ESTIMATED CENTER LOCATION. THE 06Z DVORAK
INTENSITY ESTIMATES FROM TAFB AND SAB WERE BOTH 2.5/35 KT...AND ON
THIS BASIS THE CYCLONE IS UPGRADED TO A TROPICAL STORM. THE
STRUCTURE OF KATIA IS CONSISTENT WITH THE 15-20 KT OF
EAST-NORTHEASTERLY SHEAR OVER THE CYCLONE ANALYZED BY THE SHIPS
MODEL AND UW-CIMSS. THIS SHEAR SHOULD DECREASE IN THE NEXT 12 HOURS
OR SO...AND AFTER THAT TIME STEADY INTENSIFICATION SHOULD COMMENCE
AS THE CYCLONE MOVES OVER PROGRESSIVELY HIGHER OCEAN HEAT CONTENT.
MOST OF THE INTENSITY GUIDANCE HAS TRENDED UPWARD THIS CYCLE...AND
THE OFFICIAL FORECAST HAS AS WELL. KATIA IS EXPECTED TO BE NEAR
HURRICANE STRENGTH WITHIN 36 TO 48 HOURS WITH CONTINUED
STRENGTHENING TO NEAR MAJOR HURRICANE STATUS BY THE END OF THE
PERIOD. THE NHC FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS THAT
INCLUDES THE HFIP INTENSITY AIDS.
A TIMELY AMSR-E PASS FROM 0326Z WAS HELPFUL IN LOCATING THE CENTER
ON THE EASTERN EDGE OF THE DEEP CONVECTION...WHICH WAS A BIT NORTH
OF PREVIOUS ESTIMATES. THE INITIAL MOTION ESTIMATE IS 290/15...AS
KATIA CONTINUES TO BE STEERED WEST-NORTHWESTWARD BY THE SUBTROPICAL
RIDGE TO ITS NORTH. THE MODEL GUIDANCE IS IN GOOD AGREEMENT ON A
CONTINUATION OF THIS GENERAL MOTION THROUGH THE PERIOD AS THE
MID-LEVEL RIDGE BUILDS WESTWARD TO THE NORTH OF THE CYCLONE. AT
DAYS 4 AND 5...THE WESTERN EDGE OF THE RIDGE BEGINS TO WEAKEN AS A
MID-LEVEL TROUGH AMPLIFIES OVER THE WESTERN ATLANTIC...WHICH SHOULD
RESULT IN SOME DECREASE IN FORWARD SPEED. THE TRACK GUIDANCE
REMAINS TIGHTLY CLUSTERED BUT THERE ARE SOME FORWARD SPEED
DIFFERENCES...WITH THE UKMET AND GFDL MODELS ON THE FAST SIDE OF
THE GUIDANCE AND THE GFS CONTINUING TO BE A SLOW OUTLIER. FOR THIS
CYCLE THE MODELS HAVE TRENDED FASTER DURING THE FIRST 72 HOURS...
AND SO HAS THE OFFICIAL FORECAST. OTHERWISE...THE NHC FORECAST IS
VERY CLOSE TO THE PREVIOUS ONE AND LIES NEAR OR A LITTLE TO THE
RIGHT OF THE TVCA MULTI-MODEL CONSENSUS THROUGH THE PERIOD.
"NASSAU, Bahamas, Thursday August 25, 2011 - A large and dangerous Category 3 Hurricane Irene is unleashing its fury over the northwestern Bahamas this morning after causing flooding, damaging and destroying several homes, and disrupting electricity service in the islands in the southeast of the archipelago yesterday.
The National Emergency Management Agency (NEMA) has reported that in Acklins, around 90 percent of the settlement of Lovely Bay had been wiped out, and house roofs and several homes were blown away. Power lines and trees were downed and residents have flocked to shelters."
HURRICANE IRENE DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
1100 AM EDT TUE AUG 23 2011
THE LAST FEW VISIBLE SATELLITE IMAGES SHOW A HINT OF AN EYE... WHILE
RECENT MICROWAVE DATA SHOW AN EYEWALL THAT IS OPEN TO THE SOUTH.
THE LATEST SATELLITE INTENSITY ESTIMATES FROM SAB AND TAFB WERE 77
AND 90 KT...RESPECTIVELY...AND SUPPORT MAINTAINING AN INITIAL
INTENSITY OF 85 KT. THE RECONNAISSANCE AIRCRAFT SCHEDULED TO
INVESTIGATE IRENE THIS MORNING HAD ISSUES WITH THE ON-BOARD RADAR.
THIS REQUIRED A CHANGE IN AIRCRAFT AND THE NEW PLANE JUST PASSED
THROUGH THE CENTER...REPORTING A MINIMUM PRESSURE OF 980 MB...ABOUT
THE SAME AS DURING THE PREVIOUS MISSION.
A SHEAR ANALYSIS FROM UW-CIMSS SHOWS ABOUT 10-20 KT OF SOUTHWESTERLY
SHEAR OVER IRENE....AND THE SHIPS GUIDANCE DOES NOT WEAKEN THIS
SHEAR DURING THE NEXT COUPLE OF DAYS. AS A RESULT...THE SHIPS/LGEM
MODELS DO NOT SHOW MUCH STRENGTHENING DURING THAT TIME. ON THE
OTHER HAND...THE GFDL/HWRF MODELS ARE MUCH MORE AGGRESSIVE AND MAKE
IRENE A MAJOR HURRICANE WITHIN 24 HOURS. THE NEW INTENSITY FORECAST
IS HIGHER THAN THE STATISTICAL GUIDANCE...BUT NOT AS AGGRESSIVE AS
THE GFDL/HWRF. THE UPDATED FORECAST IS SLIGHTLY BELOW THE PREVIOUS
ADVISORY.
IRENE HAS BEEN MOVING WEST-NORTHWESTWARD OR 295 DEGREES AT 10 KT. A
MID/UPPER-LEVEL TROUGH MOVING OVER THE NORTHEASTERN UNITED STATES
IS EXPECTED TO WEAKEN THE WESTERN PORTION OF THE SUBTROPICAL RIDGE
DURING THE NEXT DAY OR SO. THIS SHOULD ALLOW IRENE TO TURN
NORTHWESTWARD WITHIN THE NEXT 24-36 HOURS...AND THE TRACK GUIDANCE
IS IN EXCELLENT AGREEMENT DURING THE FIRST 48 HOURS. LATER IN THE
FORECAST PERIOD IRENE IS FORECAST TO TURN NORTHWARD AS IT ROUNDS
THE WESTERN PORTION OF THE RIDGE. THE SPREAD IN THE GUIDANCE
INCREASES BY DAY THREE...RANGING FROM THE COASTAL MID-ATLANTIC
STATES TO WELL OFFSHORE...WITH THE UKMET ALONG THE LEFT SIDE AND
THE GFS/NOGAPS ALONG THE RIGHT SIDE OF THE GUIDANCE ENVELOPE. THE
UPDATED TRACK IS CLOSEST TO THE ECMWF AND IS A LITTLE LEFT OF THE
MULTI-MODEL CONSENSUS. IT IS IMPORTANT TO REMIND USERS NOT TO FOCUS
ON THE EXACT FORECAST TRACK...ESPECIALLY AT DAYS 4 AND 5...SINCE
THE MOST RECENT 5-YEAR AVERAGE ERRORS AT THOSE FORECAST TIMES ARE
200 AND 250 MILES...RESPECTIVELY.
HURRICANE IRENE DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
500 AM EDT TUE AUG 23 2011
SMOOTHING THROUGH ALL OF THE AIRCRAFT FIXES SINCE IRENE MOVED OFF
THE COAST OF PUERTO RICO MORE THAN 18 HOURS AGO YIELDS A LONG TERM
MOTION OF 295/10 KT...WHICH IS USED FOR THIS ADVISORY. THERE IS NO
SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. THE
23/00Z G-IV JET AIRCRAFT AND AIR FORCE C-130 DROPSONDE DATA APPEAR
TO HAVE SETTLED DOWN THE MODELS...AND THERE IS CONSIDERABLY LESS
DIFFERENCE AMONG THE VARIOUS MODEL SOLUTIONS NOW. THE OVERWHELMING
CONSENSUS IS THAT IRENE WILL GRADUALLY TURN NORTHWESTWARD OVER THE
NEXT 2-3 DAYS AND THEN MOVE NORTHWARD THROUGH A DEVELOPING BREAK IN
THE SUBTROPICAL RIDGE OVER THE SOUTHEASTERN UNITED STATES. THE
OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND
LIES VERY CLOSE TO CONSENSUS MODELS TVCN AND TVCA.
AN EARLIER RECON FLIGHT INDICATED THE PRESSURE HAD ONLY FALLEN BY 2
MB DOWN TO 978 MB...AND THE OVERALL APPEARANCE IN SATELLITE IMAGERY
HAS CHANGED LITTLE SINCE THE PREVIOUS ADVISORY. AS A RESULT...THE
INITIAL INTENSITY IS BEING HELD AT 85 KT...WHICH COULD BE GENEROUS.
IRENE IS FORECAST TO REMAIN IN A RELATIVELY LOW VERTICAL WIND SHEAR
ENVIRONMENT AND OVER SSTS NEAR 30C. THAT COMBINATION...ALONG WITH
EXPANDING OUTFLOW IN ALL QUADRANTS...SHOULD ALLOW FOR IRENE TO
BECOME A MAJOR HURRICANE WITHIN THE NEXT 24 HOURS ONCE THE CYCLONE
CLEARS THE EFFECTS OF HISPANIOLA...AND PROBABLY MAINTAIN MAJOR
HURRICANE STATUS THROUGHOUT THE REMAINDER OF THE 5-DAY FORECAST
PERIOD. THE INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY
AND CLOSELY FOLLOWS A BLEND OF THE HWRF AND GFDL MODEL INTENSITY
FORECASTS...AND CONVERSION OF THE SURFACE PRESSURES DEPICTED IN THE
GFS AND ECMWF MODELS.
WIND RADII WERE EXPANDED BASED ON A BLEND OF RECON FLIGHT-LEVEL
WINDS...SFMR WINDS...AND SURFACE OBSERVATIONS.
IRENE IS FORECAST TO BECOME A LARGER THAN AVERAGE HURRICANE. IT IS
IMPORTANT TO REMIND USERS NOT TO FOCUS ON THE EXACT FORECAST
TRACK...ESPECIALLY AT DAYS 4 AND 5...SINCE THE MOST RECENT 5-YEAR
AVERAGE ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES...
RESPECTIVELY.
HURRICANE IRENE DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
500 PM AST MON AUG 22 2011
DATA FROM THE LAST AIR FORCE HURRICANE HUNTER AIRCRAFT AROUND 1700
UTC INDICATE THAT THE CENTRAL PRESSURE WAS STEADY AND THE WINDS
HAVE NOT CHANGED DURING THE DAY. SINCE THEN...HIGH RESOLUTION
SATELLITE IMAGES REVEAL SOME CONVECTIVE BANDS WRAPPING AROUND A
CLUSTER OF DEEP CONVECTION NEAR THE CENTER...SUGGESTING THAT IRENE
COULD BE SLOWLY INTENSIFYING. HOWEVER...DVORAK T-NUMBERS ARE 4.0
AND 4.5 WHICH SUPPORTS KEEPING THE INITIAL INTENSITY AT 70 KNOTS.
ANOTHER PLANE WILL CHECK THE HURRICANE AROUND 0000 UTC TONIGHT.
WITH THE EXCEPTION OF THE DISRUPTION OF THE OUTER CIRCULATION BY
THE HIGH TERRAIN OF HISPANIOLA...WHICH PROBABLY WILL SLOW DOWN THE
INTENSIFICATION PROCESS DURING THE NEXT 12 TO 24 HOURS...ALL OF THE
INGREDIENTS ARE CONDUCIVE FOR IRENE TO INTENSIFY OVER THE NEXT FEW
DAYS. THE OFFICIAL FORECAST CALLS FOR IRENE TO BECOME A STRONG
CATEGORY 2 OR CATEGORY 3 HURRICANE ON THE SAFFIR-SIMPSON HURRICANE
WIND SCALE AS IRENE MOVES ACROSS THE CENTRAL AND NORTHWESTERN
BAHAMAS. IN FACT...BOTH THE GFS AND THE ECMWF GLOBAL MODELS INSIST
ON MAKING IRENE A LARGE AND STRONG HURRICANE WITH MINIMUM PRESSURES
AROUND 945 MB AND 952 MB...RESPECTIVELY.
IRENE IS MOVING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 11
KNOTS. CURRENTLY...THE MOTION OF THE HURRICANE IS BEING CONTROLLED
BY A NARROW SUBTROPICAL RIDGE TO ITS NORTH. HOWEVER...THE FUTURE
TRACK WILL DEPEND ON THE DEVELOPMENT OF A LARGE MID- TO UPPER-LEVEL
TROUGH ALONG THE EAST COAST OF THE UNITED STATES. THIS PATTERN WILL
INDUCE A GRADUAL NORTHWESTWARD AND THEN NORTHWARD TRACK THROUGH THE
FORECAST PERIOD WITH A SLIGHT DECREASE IN FORWARD SPEED. THERE IS
MORE CONFIDENCE IN THE FORECAST SINCE MOST OF THE TRACK MODELS...
WITH THE EXCEPTION OF THE GFDL...HAVE NOW FOLLOWED THE LEAD OF THE
ECMWF MODEL. THE GUIDANCE IS NOW IN BETTER AGREEMENT IN TURNING
IRENE NORTHWARD ALONG 78 OR 79 DEGREES LONGITUDE. ALTHOUGH IT IS
STILL TOO EARLY TO BE CERTAIN...THE GUIDANCE TREND CONTINUES TO
LESSENS THE THREAT TO SOUTH FLORIDA BUT INCREASES THE THREAT TO THE
CAROLINAS.
DO 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.
The Turks and Caicos and The Bahamas are low lying islands, basically sand bars and coral reefs. Category 3, 4, or 5 hurricanes can cause serious damage to these islands. This storm is looking potentially disastrous for these islands, and possibly for somewhere on the east coast of the U.S. if and when it makes landfall there (the models have brought it further and further east as the days have passed but they seem to be in agreement now).
Puerto Rico was was much harder hit than the Virgin Islands, which are not far away at all:
Irene is a hurricane and forecast to become a strong and dangerous one before she leaves the region. Puerto Rico is in the path at the moment, but then Hispaniola, the Turks and Caicos, and Bahamas are in line. Anyone on or traveling to those islands needs to be prepared immediately.
TROPICAL STORM IRENE SPECIAL DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
700 PM AST SAT AUG 20 2011
AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE
TROPICAL WAVE EAST OF THE LESSER ANTILLES FOUND A SMALL LOW-LEVEL
CIRCULATION CENTER JUST SOUTHWEST OF A LARGE CONVECTIVE BURST AND A
MINIMUM PRESSURE OF ABOUT 1006 MB. THE PLANE ALSO MEASURED A
MAXIMUM WIND OF 53 KT AT 1400 FT AND BELIEVABLE WINDS OF ABOUT
45 KT FROM THE SFMR. THUS ADVISORIES ARE BEING INITIATED ON
TROPICAL STORM IRENE WITH AN INITIAL INTENSITY OF 45 KT.
A ROUGH ESTIMATE OF INITIAL MOTION IS ABOUT 280/19. A LARGE
MID-LEVEL RIDGE OVER THE CENTRAL AND WESTERN TROPICAL ATLANTIC IS
EXPECTED TO STEER IRENE TOWARD THE WEST-NORTHWEST OVER THE NEXT TWO
OR THREE DAYS. THIS RIDGE SHOULD WEAKEN DURING THAT TIME AND CAUSE
IRENE TO GRADUALLY DECELERATE. THE GUIDANCE IS IN GOOD AGREEMENT
ON A TRACK GENERALLY IN THE DIRECTION OF HISPANIOLA TO THE SOUTH OF
PUERTO RICO. THEREAFTER...A MID-LATITUDE TROUGH MOVING OFFSHORE OF
THE EASTERN UNITED STATES IS EXPECTED TO CAUSE A WEAKNESS IN THE
RIDGE. THIS COULD ALLOW IRENE TO GAIN SOME LATITUDE...ALTHOUGH THE
MODELS BEGIN TO SPREAD OUT LATE IN THE PERIOD. THE GFS AND ECMWF
SHOW ENOUGH OF A WEAKNESS TO BRING THE STORM NORTH OF CUBA...WHILE
THE UKMET AND THE CANADIAN HAVE ENOUGH RIDGING IN PLACE TO KEEP THE
STORM IN THE CARIBBEAN SEA. THE NHC FORECAST WILL SPLIT THOSE TWO
IDEAS AND LIES JUST TO THE WEST OF THE MODEL CONSENSUS.
THE INITIAL VORTEX IS STILL IN ITS FORMATIVE STAGES AND IT WILL
PROBABLY TAKE SOME TIME TO STRENGTHEN. HOWEVER...IRENE IS MOVING
OVER RATHER WARM WATERS WITH LIGHT SHEAR EXPECTED. MOST OF THE
RELIABLE GUIDANCE BRINGS THE STORM TO A HURRICANE BEFORE REACHING
HISPANIOLA...AND THE OFFICIAL FORECAST IS IN AGREEMENT WITH THIS
SCENARIO. THE INTENSITY FORECAST IN AT DAY 3 AND BEYOND IS RATHER
CHALLENGING DUE TO THE POTENTIAL FOR LAND INTERACTION. ALTHOUGH
THE NHC FORECAST WILL SHOW ONLY A SMALL AMOUNT OF
RE-INTENSIFICATION...ENVIRONMENTAL CONDITIONS COULD BE QUITE
FAVORABLE FOR STRENGTHENING IF IRENE AVOIDS SIGNIFICANT LAND
INTERACTION.
BASED ON THE OFFICIAL FORECAST...TROPICAL STORM WARNINGS HAVE BEEN
ISSUED FOR MANY OF THE LEEWARD ISLANDS...THE VIRGIN ISLANDS AND
PUERTO RICO.
NOTE...THIS SPECIAL ADVISORY TAKES THE PLACE OF THE STANDARD 800 PM
AST/0000 UTC INTERMEDIATE PUBLIC ADVISORY. THE NEXT ADVISORY WILL
BE THE FULL ADVISORY PACKAGE ISSUED AT 1100 PM AST/0300 UTC.
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