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Hurricane Season - 2008


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Here's the latest discussion from the NHC on Hanna.

WTNT43 KNHC 031500
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
1100 AM EDT WED SEP 03 2008

THERE HAVE BEEN SOME STRUCTURAL CHANGES WITH HANNA TODAY AS IT INTERACTS WITH THE UPPER-LEVEL LOW MOVING THROUGH THE NORTHWESTERN BAHAMAS. THE WIND FIELD HAS EXPANDED IN THE NORTHERN SEMICIRCLE AND THE LOW-LEVEL CIRCULATION CENTER HAS BECOME LESS WELL DEFINED.
VISIBLE IMAGERY SUGGESTS MULTIPLE LOW-LEVEL SWIRLS COMING OUT OF THE DEEP CONVECTION TO THE NORTH OF A MEAN CENTER... AND THE SYSTEM'S CONVECTIVE BANDS ARE WELL REMOVED FROM THE CORE. THE RECONNAISSANCE MISSION THAT ENDED AROUND 12Z REPORTED SOME SFMR WINDS OF UP TO 45 KT ABOUT 70 NM FROM THE CENTER...AND THE INITIAL INTENSITY ESTIMATE REMAINS 50 KT.

BECAUSE THE CENTER IS NOT WELL DEFINED...THE INTIAL MOTION IS HARD TO GAUGE. MY BEST ESTIMATE IS 360/5...AND THIS COULD BE THE START OF THE EXPECTED NORTHWESTWARD TURN. THE STEERING FLOW SHOULD BECOME BETTER DEFINED OVER THE NEXT 24-48 HOURS AS THE UPPER LOW MOVES WEST-SOUTHWESTWARD AND MID-LEVEL RIDGING BUILDS IN BEHIND THE LARGE DEEP-LAYER LOW OFF THE UPPER U.S. EAST COAST. MODEL GUIDANCE RESPONDS TO THIS PATTERN WITH A NORTHWESTWARD ACCELERATION WITH A RECURVATURE AROUND THE MID-LEVEL RIDGE IN ABOUT THREE DAYS. THE GUIDANCE HAS BEEN TOO FAST WITH THIS SCENARIO OVER THE PAST COUPLE OF DAYS...AND GIVEN THE POOR CORE STRUCTURE OF HANNA I AM INCLINED TO THINK THAT SUBSEQUENT INTERACTION WITH THE UPPER STEERING MAY BE
A LITTLE OVERDONE...AT LEAST INITIALLY. THE OFFICIAL FORECAST IS N BEST AGREEMENT WITH THE ECMWF AND UKMET IN TERMS OF SPEED...WITH THE GFS/HWRF/GFDL SHOWING A MORE VERTICAL SYSTEM MOVING MORE RAPIDLY. THE GUIDANCE HAS ALSO BEEN TRENDING EASTWARD OVER THE PAST FEW CYCLES... AND I HAVE SHIFTED THE TRACK SLIGHTLY IN THAT DIRECTION.

WESTERLY SHEAR AND DRY AIR ASSOCIATED WITH THE UPPER LOW WILL INHIBIT DEVELOPMENT IN THE SHORT TERM BUT SHOULD DIMINISH OVER THE NEXT COUPLE OF DAYS...TO BE REPLACED WITH MODERATE SOUTHEASTERLY SHEAR. THIS PATTERN WOULD PERMIT SOME RE-INTENSIFICATION... BUT HANNA WILL NEED TO RECREATE AN INNER CORE IN ORDER TO INTENSIFY SUBSTANTIALLY. THE AVAILABLE GUIDANCE STILL BRINGS HANNA TO MINIMAL HURRICANE INTENSITY AND THE OFFICIAL FORECAST IS JUST ABOVE THIS GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INITIAL 03/1500Z 20.6N 71.8W 50 KT
12HR VT 04/0000Z 21.5N 72.0W 50 KT
24HR VT 04/1200Z 23.4N 73.3W 55 KT
36HR VT 05/0000Z 25.2N 75.2W 60 KT
48HR VT 05/1200Z 27.3N 77.1W 65 KT
72HR VT 06/1200Z 33.0N 79.0W 70 KT
96HR VT 07/1200Z 42.0N 71.0W 35 KT...INLAND EXTRATROPICAL
120HR VT 08/1200Z 47.0N 60.0W 35 KT...EXTRATROPICAL

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1100 PM AST WED SEP 03 2008

...IKE BECOMES AN EXTREMELY DANGEROUS CATEGORY FOUR HURRICANE...

AT 1100 PM AST...0300Z...THE CENTER OF HURRICANE IKE WAS LOCATED
NEAR LATITUDE 22.1 NORTH...LONGITUDE 54.1 WEST OR ABOUT 610 MILES...
980 KM...NORTHEAST OF THE LEEWARD ISLANDS.

IKE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 17 MPH...28 KM/HR...AND
THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH EARLY
THURSDAY...FOLLOWED BY A TURN TO THE WEST ON THURSDAY NIGHT AND
FRIDAY...TAKING IKE OVER THE OPEN WATERS OF THE WEST-CENTRAL
ATLANTIC DURING THE NEXT COUPLE OF DAYS. IT IS TOO EARLY TO
DETERMINE WHAT IF ANY LAND AREAS MIGHT EVENTUALLY BE AFFECTED BY
IKE.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR NEAR 135 MPH...215
KM/HR...WITH HIGHER GUSTS. IKE IS AN EXTREMELY DANGEROUS CATEGORY
FOUR HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE. SOME
FLUCTUATIONS IN INTENSITY ARE EXPECTED DURING THE NEXT DAY OR
TWO.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 160
MILES...260 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 948 MB...27.99 INCHES.

REPEATING THE 1100 PM AST POSITION...22.1 N...54.1 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 17 MPH. MAXIMUM SUSTAINED WINDS...135
MPH. MINIMUM CENTRAL PRESSURE...948 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
500 AM AST.

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Here's the latest general discussion by the NHC regarding these storms.

AXNT20 KNHC 041202
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU SEP 04 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM HANNA AT 04/1200 UTC IS NEAR 24.1N 73.1W... OR ABOUT 325 MILES/525 KM EAST-SOUTHEAST OF NASSAU IN THE BAHAMAS. HANNA IS MOVING NORTHWEST 10 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 990 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 60 KT WITH GUSTS TO 75 KT. THE DEEP CONVECTIVE PRECIPITATION OF HANNA IS BEING RIPPED UP AND CUT UP BY THE FLOW AROUND THE MIDDLE TO UPPER LEVEL TROUGH TO THE WEST OF HANNA. INDIVIDUAL CELLS OF SHOWERS
AND POSSIBLE THUNDERSTORMS ARE IN A LINE FROM 22N TO 30N BETWEEN 67W AND 71W.

THE CENTER OF HURRICANE IKE AT 04/0900 UTC IS NEAR 22.7N 55.8W MOVING WEST-NORTHWEST 15 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 935 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 125 KT
WITH GUSTS TO 155 KT. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FROM 21N TO 24N
BETWEEN 54W AND 57W.

THE CENTER OF TROPICAL STORM JOSEPHINE AT 04/0900 UTC IS NEAR 14.2N 31.3W MOVING WEST-NORTHWEST 10 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 50 KT WITH GUSTS TO 60 KT. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FROM 14N TO 17N BETWEEN 29W AND 33W.

...TROPICAL WAVES...
ONE TROPICAL WAVE IS GETTING READY TO MOVE OFF THE COAST OF AFRICA...SPARKING ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS FROM 13N TO 19N BETWEEN 16W AND 22W.

DISCUSSION...

THE GULF OF MEXICO...THE YUCATAN PENINSULA/GUATEMALA/MEXICO.. A WEAK MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM SOUTHWESTERN LOUISIANA TO THE LOWER TEXAS COAST/NORTHEASTERN MEXICO. BROAD SURFACE LOW PRESSURE AND A TROUGH COINCIDE WITH THE MIDDLE TO UPPER LEVEL TROUGH. SHOWERS ARE DEVELOPING ALONG THE SOUTH CENTRAL LOUISIANA COAST...AND REMAIN ALONG THE LOWER TEXAS COAST...AND IN THE SOUTHWESTERN CORNER OF THE AREA SOUTH OF 21N. ANOTHER WEAK MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM THE CENTRAL GULF OF MEXICO NEAR 26N89W TO THE NORTHEASTERN YUCATAN PENINSULA TO 19N86W IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA. AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS IN THE SOUTHWESTERN CORNER OF THE AREA.

FROM THE BAHAMAS ACROSS CUBA INTO THE NORTHWESTERN CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL TROUGH STARTS FROM A 23N76W CYCLONIC CIRCULATION CENTER...CROSSES EASTERN CUBA NEAR 21N77W... AND ENTERS THE NORTHWESTERN CARIBBEAN SEA NEAR 17N83W...REACHING WESTERN HONDURAS NEAR 15N88W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE SOUTHEAST OF A LINE FROM THE NICARAGUA/HONDURAS BORDER NEAR 15N83W TO THE HAITI COAST
NEAR 18N73W...TO THE PRECIPITATION WITH THE INVERTED TROUGH. THE REST OF THE CARIBBEAN SEA EAST OF THE 23N76W 15N88W TROUGH... UPPER LEVEL ANTICYCLONIC OUTFLOW FROM TROPICAL STORM HANNA
COVERS THE AREA EAST OF 67W/68W. A MIDDLE TO UPPER LEVEL INVERTED TROUGH ROLLS WESTWARD FROM THE ATLANTIC OCEAN INTO THE EXTREME EASTERN PART OF THE CARIBBEAN SEA. DRY AIR IN SUBSIDENCE IS EAST OF 67/68W. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 10N TO 14N BETWEEN 69W AND 74W FROM THE CARIBBEAN SEA TO NORTHERN COLOMBIA AND NORTHWESTERN VENEZUELA TO THE WEST OF THE INVERTED TROUGH.

THE ATLANTIC OCEAN...
THE BASE OF A MIDDLE TO UPPER LEVEL LONGWAVE TROUGH REACHES 33N70W FROM POINTS TO THE NORTH. THIS TROUGH IS COMPLETELY SEPARATED FROM THE TROUGH THAT IS JUST TO THE WEST OF TROPICAL STORM HANNA. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 20N39W IN THE MIDDLE OF TROPICAL STORM JOSEPHINE AND HURRICANE IKE. CYCLONIC FLOW GOES FROM 14N TO 28N BETWEEN 34W AND 50W.

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Here's the NHC detailed discussion of Hanna:

WTNT43 KNHC 040900
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
500 AM EDT THU SEP 04 2008

LOOKS CAN CERTAINLY BE DECEIVING. HANNA HAS NOT BEEN PRODUCING VERY MUCH DEEP CONVECTION SINCE AN EARLIER STRONG BURST DIED AFTER ABOUT 04Z...AS THE UPPER-LEVEL LOW TO ITS WEST CONTINUES TO IMPOSE STRONG SOUTHERLY SHEAR. NEVERTHELESS...HANNA HAS A LARGE AND ROBUST
CIRCULATION...AND A NOAA RECONNAISSANCE AIRCRAFT HAS RECENTLY REPORTED A MINIMUM CENTRAL PRESSURE OF 990 MB. FLIGHT-LEVEL WINDS AT 850 MB HAVE BEEN AS STRONG AS 65 KT...AND NUMEROUS SFMR VALUES OF 55-60 KT HAVE BEEN RETRIEVED. I HAVE NO GOOD REASON TO DISCOUNT THE SFMR WINDS...SO THE INITIAL INTENSITY IS INCREASED TO 60 KT. GIVEN THAT THE SOUTHERLY SHEAR IS FORECAST BY THE DYNAMICAL MODELS TO PERSIST OVER HANNA EVEN AS IT GAINS LATITUDE DURING THE NEXT
COUPLE OF DAYS...STRENGTHENING WOULD AT FIRST GLANCE SEEM UNLIKELY. CONSISTENT WITH THAT THINKING...THE GFDL AND HWRF SHOW LITTLE CHANGE IN STRENGTH OR EVEN SOME WEAKENING...EXCEPT MUCH LATER WHEN HANNA BECOMES AN EXTRATROPICAL CYCLONE. ON THE OTHER HAND...THE
SHIPS AND LGEM...DESPITE DIAGNOSING LITTLE CHANGE IN SHEAR...FORECAST A LITTLE STRENGTHENING TO HURRICANE STATUS. A CONSENSUS OF THESE VARIOUS MODELS WOULD YIELD A FLAT 60 KT
INTENSITY FORECAST UNTIL HANNA PASSES NEAR OR OVER THE CAROLINAS...BUT FOR CONTINUITY AND SINCE HANNA IS ALREADY PRODUCING WINDS JUST SHY OF HURRICANE STRENGTH....65 KT IS STILL SHOWN
EXPLICITLY IN THE FORECAST. GRADUAL WEAKENING IS THEN FORECAST AS HANNA ACCELERATES NORTHEASTWARD AND BECOMES EXTRATROPICAL.


DESPITE HAVING AIRCRAFT FIXES...THE INITIAL MOTION IS HARD TO GAGE...PROBABLY DUE TO THE SPRAWLING NATURE OF THE CIRCULATION...BUT THE INITIAL MOTION ESTIMATE IS 320/10. HANNA SHOULD ROUND THE BUILDING WESTERN ATLANTIC RIDGE AND ROUGHLY HUG THE EAST COAST OF THE UNITED STATES...BUT PASSING NEAR OR OVER THE COAST OF THE CAROLINAS ALONG THE WAY. PERHAPS DUE IN PART TO THE BENEFIT OF DATA FROM THE NOAA G-IV JET MISSION LAST NIGHT...THE LATEST MODEL TRACKS HAVE COME INTO A LITTLE TIGHTER AGREEMENT...AND IN GENERAL THEY HAVE SHIFTED SLIGHTLY TO THE LEFT. THE NEW TRACK FORECAST IS SHIFTED JUST SLIGHTLY LEFT OF THE PREVIOUS ONE...TO BE
CLOSER TO THE CONSENSUS. AS ALWAYS...ONE SHOULD NOT FOCUS ON THE EXACT FORECAST OF THE CENTER...ESPECIALLY SINCE MUCH OF THE WEATHER ASSOCIATED WITH HANNA IS WELL-REMOVED FROM THE CENTER.

FORECAST POSITIONS AND MAX WINDS

INITIAL 04/0900Z 24.0N 72.8W 60 KT
12HR VT 04/1800Z 25.3N 74.1W 60 KT
24HR VT 05/0600Z 27.5N 76.6W 60 KT
36HR VT 05/1800Z 30.3N 78.4W 65 KT
48HR VT 06/0600Z 33.5N 78.4W 65 KT
72HR VT 07/0600Z 41.0N 72.5W 50 KT...INLAND
96HR VT 08/0600Z 48.5N 59.0W 45 KT...EXTRATROPICAL
120HR VT 09/0600Z 51.5N 41.0W 45 KT...EXTRATROPICAL

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Here's the discussion for Ike:

WTNT44 KNHC 040838
TCDAT4
HURRICANE IKE DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008
500 AM EDT THU SEP 04 2008

SATELLITE IMAGES INDICATE THAT IKE HAS INTENSIFIED FURTHER... WITH THE EYE EMBEDDED IN EVEN COLDER CLOUD TOPS THAN BEFORE. THE LATEST DVORAK DATA T-NUMBERS ARE UP TO 6.5 WHICH SUPPORTS AN INTENSITY OF 125 KT...AND THIS IS USED FOR THE CURRENT ADVISORY. IN SUCH INTENSE HURRICANES...FLUCTUATIONS IN STRENGTH DUE TO INNER-CORE EVOLUTIONS SUCH AS EYEWALL REPLACEMENTS ARE NEARLY IMPOSSIBLE TO PREDICT. HOWEVER...THE SHIPS MODEL SHOWS OVER 30 KT OF VERTICAL SHEAR ON IKE WITHIN THE NEXT 24-36 HOURS DUE TO A STRENGTHENING UPPER-LEVEL HIGH TO THE NORTHWEST OF THE HURRICANE. THIS LARGE-SCALE ENVIRONMENTAL INFLUENCE SHOULD INDUCE SOME WEAKENING... AND THAT IS WHAT IS INDICATED IN THE OFFICIAL WIND SPEED FORECAST.


LATER ON IN THE FORECAST PERIOD...SOME RE-STRENGTHENING IS PROBABLE AS THE SHEAR WEAKENS AND THE THERMODYNAMIC ENVIRONMENT IS EXPECTED TO BE FAVORABLE. THE OFFICIAL FORECAST MIGHT BE CONSERVATIVE BUT IT REFLECTS OUR LACK OF SKILL IN FORECASTING TROPICAL CYCLONE INTENSITY IN 3-5 DAYS.

IKE CONTINUES TO MOVE WEST-NORTHWESTWARD OR AROUND 290/15. THERE HAS BEEN LITTLE CHANGE TO THE TRACK FORECAST OR FORECAST REASONING. A DEEP-LAYER HIGH IS DEPICTED BY THE GLOBAL MODELS TO BUILD TO THE NORTHWEST OF THE HURRICANE WITHIN THE NEXT COUPLE OF DAYS. THIS WOULD LIKELY CAUSE THE HEADING OF IKE TO BEND WESTWARD TO WEST-SOUTHWESTWARD. LATE IN THE FORECAST PERIOD IT IS EXPECTED THAT IKE WILL HAVE PASSED THE CENTER OF THE HIGH...AND TURN BACK
TOWARD THE WEST AND WEST-NORTHWEST. THE BIG QUESTIONS IS HOW THE HURRICANE RESPONDS TO THE WEAKNESS IN THE MID-TROPOSPHERIC RIDGE OVER THE SOUTHEASTERN U.S. AROUND DAY 5. LOOKING AT THE VARIOUS TRACK MODELS IN THIS TIME FRAME...WE SEE THAT THE ECMWF IS THE WESTERNMOST AND THE GFS IS THE NORTHEASTERNMOST. THE OFFICIAL TRACK FORECAST LIES BETWEEN THESE EXTREMES AND LEANS TOWARD THE ECMWF. THIS IS A LITTLE TO THE LEFT OF THE DYNAMICAL MODEL CONSENSUS AND QUITE SIMILAR TO THE PREVIOUS NHC FORECAST.

BECAUSE OF THE UNCERTAINTIES IN 4- AND 5-DAY TRACK FORECASTS...IT IS STILL TOO EARLY TO SAY WHAT LAND AREAS ARE LIKELY TO BE IMPACTED BY THIS HURRICANE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 04/0900Z 22.7N 55.8W 125 KT
12HR VT 04/1800Z 23.5N 57.7W 125 KT
24HR VT 05/0600Z 24.0N 60.2W 115 KT
36HR VT 05/1800Z 24.0N 62.6W 110 KT
48HR VT 06/0600Z 23.4N 64.9W 110 KT
72HR VT 07/0600Z 22.5N 69.5W 115 KT
96HR VT 08/0600Z 23.0N 73.5W 115 KT
120HR VT 09/0600Z 25.0N 76.5W 115 KT

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Here's Josephine's NHC discussion:

WTNT45 KNHC 040836
TCDAT5
TROPICAL STORM JOSEPHINE DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102008
500 AM EDT THU SEP 04 2008

CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY INDICATE THAT DEEP CONVECTION HAS REDEVELOPED IN THE NORTHERN SEMICIRCLE AND THAT THE LOW-LEVEL CENTER HAS MOVED FURTHER INTO THE SOUTHERN PORTION OF THE CONVECTIVE CLOUD MASS. SATELLITE INTENSITY ESTIMATES ARE T3.5/55 KT AND T3.0/45 KT FROM TAFB AND SAB... RESPECTIVELY...SO THE INITIAL INTENSITY HAS BEEN INCREASED TO 50 KT. HOWEVER... IF THE LOW-LEVEL CENTER IS FARTHER NORTH INTO THE CONVECTION...THEN JOSEPHINE WILL
BE STRONGER THAN INDICATED IN THIS ADVISORY.

THE INITIAL MOTION ESTIMATE IS 285/9...BASED MAINLY ON MICROWAVE SATELLITE POSITION ESTIMATES OVER THE PAST 9 HOURS. JOSEPHINE IS FORECAST TO MOVE IN A GENERAL WEST-NORTHWESTWARD MOTION ALONG THE SOUTHERN PERIPHERY OF LARGE SUBTROPICAL RIDGE FOR THE NEXT 48-72 HOURS. AFTER THAT...A WEAKNESS IS FORECAST TO DEVELOP IN THE RIDGE ...WHICH SHOULD ALLOW JOSEPHINE TO MAKE A POLEWARD JOG AT DAYS 3 AND 4... BEFORE THE RIDGE FILLS BACK IN FORCING THE CYCLONE ON A LITTLE
MORE WESTWARD BY 120 HOURS. THE OFFICIAL FORECAST TRACK IS TO THE RIGHT OF THE PREVIOUS TRACK...BUT REMAINS TO THE LEFT OF THE MODEL CONSENSUS AND CONTINUES ALONG THE SOUTHERN EDGE OF THE NHC MODEL GUIDANCE ENVELOPE.

ALTHOUGH JOSEPHINE IS EXPERIENCING SOUTH-SOUTHWESTERLY VERTICAL WIND SHEAR OF 20 TO 25 KT...THE CYCLONE IS LOCATED IN A REGION OF MODERATE DIFLUENCE IN SOUTHEASTERN QUADRANT OF A LARGE UPPER-LEVEL LOW THAT IS SITUATED ABOUT MIDWAY BETWEEN JOSEPHINE AND MAJOR HURRICANE IKE. THIS UPPER-AIR PATTERN IS FORECAST TO PROPAGATE WESTWARD IN TANDEM WITH JOSEPHINE AND IKE FOR THE NEXT 48 HOURS... AFTER WHICH THE UPPER-LEVEL LOW IS EXPECTED TO GRADUALLY FILL AND
LIFT OUT TO THE NORTH. THE SHIPS INTENSITY MODEL MAINTAINS SOUTHERLY SHEAR OF ABOUT 20 KT THROUGH 72 HOURS...AND THEN INDICATES THE VERTICAL SHEAR WILL DECREASE TO 10 TO 15 KT AFTER
THAT. THE OFFICIAL FORECAST FOLLOWS THE SHIPS MODEL BY HOLDING THE INTENSITY STEADY THROUGHOUT THE FORECAST PERIOD. HOWEVER... IF JOSEPHINE REMAINS NEAR OR SOUTH OF 20N LATITUDE BY DAYS 4 AND 5... THEN THE CYCLONE WILL BE BENEATH UPPER-LEVEL ANTICYCLONIC FLOW AND WEAK SHEAR...WHICH WOULD ALLOW FOR STRENGTHENING TO OCCUR. THIS SCENARIO WILL BE EVALUATED IN SUBSEQUENT FORECAST PACKAGES.


FORECAST POSITIONS AND MAX WINDS
INITIAL 04/0900Z 14.2N 31.3W 50 KT
12HR VT 04/1800Z 14.5N 32.9W 50 KT
24HR VT 05/0600Z 15.0N 35.0W 50 KT
36HR VT 05/1800Z 15.7N 37.1W 50 KT
48HR VT 06/0600Z 16.4N 39.1W 50 KT
72HR VT 07/0600Z 17.9N 42.8W 50 KT
96HR VT 08/0600Z 19.5N 47.0W 50 KT
120HR VT 09/0600Z 21.0N 51.5W 50 KT

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