[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 02 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.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION GUSTAV IS MOVING SLOWLY ACROSS NORTHWEST
LOUISIANA. AT 02/1500... ITS CENTER IS NEAR 32.4N 93.6W...OR
ABOUT 13 NM...25 KM...EAST SOUTHEAST OF SHREVEPORT LOUISIANA.
THE DEPRESSION IS MOVING TOWARD THE N-NW AT 7 KT...13 KM/HR.
THIS MOTION IS EXPECTED TO CONTINUE WITH A GRADUAL TURN TOWARDS
THE NORTH TONIGHT AND WEDNESDAY. MAXIMUM SUSTAINED WINDS ARE 22
KT...40 KM/HR...WITH HIGHER GUSTS. THE MINIMUM CENTRAL PRESSURE
IS 992 MB. STORM TOTAL RAINFALLS ARE EXPECTED TO BE FIVE TO TEN
INCHES WITH ISOLATED MAXIMUM OF FIFTEEN INCHES OVER PORTIONS OF
LOUISIANA...ARKANSAS...AND MISSISSIPPI.  FOUR TO SIX INCHES WITH
A MAXIMUM OF EIGHT INCHES IS EXPECTED OVER MISSOURI AND WEST
CENTRAL ILLINOIS.  THREE TO FIVE INCHES OF RAIN IS POSSIBLE OVER
FAR NORTHEAST TEXAS AND FAR EASTERN OKLAHOMA. RAINFALL AMOUNTS
OF 4-8 INCHES HAVE BEEN ALREADY REPORTED IN PARTS OF
ALABAMA...MISSISSIPPI AND LOUISIANA.

HURRICANE HANNA IS CENTERED NEAR 20.6N 72.9W AT 02/1800 UTC OR
JUST SOUTHEAST OF GREAT INAGUA ISLAND IN THE SOUTHEASTERN
BAHAMAS AND ABOUT 420 MILES...680 KM...SOUTHEAST OF NASSAU.
HANNA HAS BEEN DRIFTING SOUTHEASTWARD TODAY. HOWEVER...A
NORTHWESTWARD MOTION IS EXPECTED TO BEGIN TONIGHT OR TOMORROW.
HANNA WILL MOVE OVER THE SOUTHEASTERN BAHAMAS TONIGHT AND INTO
THE CENTRAL BAHAMAS TOMORROW. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 985 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO
75 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. A SLOW MOTION TOWARD THE
SOUTH-SOUTHWEST IS EXPECTED TONIGHT FOLLOWED BY A GRADUAL TURN
TOWARD THE WEST AND NORTHWEST ON TUESDAY. HANNA IS PRODUCING
HEAVY RAINS OVER THE SOUTHEASTERN BAHAMAS AND HISPANIOLA. THIS
TROPICAL CYCLONE IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO
8 INCHES...WITH ISOLATED AMOUNTS OF 12 INCHES...OVER THE
SOUTHEASTERN BAHAMAS...THE TURKS AND CAICOS ISLANDS...AND
EASTERN CUBA. RAINFALL TOTALS OF 6 TO 10 INCHES...WITH ISOLATED
MAXIMUM AMOUNTS OF UP TO 20 INCHES...ARE POSSIBLE OVER
HISPANIOLA WHERE THESE RAINS COULD CAUSE LIFE-THREATENING
MUDSLIDES AND FLASH FLOODING. THE NATIONAL HURRICANE CENTER
ISSUED ITS LAST ADVISORY ON TROPICAL DEPRESSION GUSTAV AT
02/0900 UTC.

TROPICAL STORM IKE IS CENTERED NEAR 18.9N 45.0W AT 02/1500 UTC
OR ABOUT 965 NM...1785 KM...EAST OF THE LEEWARD ISLANDS MOVING W
AT 16 KT...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE
DURING THE NEXT TWO DAYS. ESTIMATED MINIMUM CENTRAL PRESSURE IS
1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60
KT. GRADUAL STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS
AND IKE COULD BECOME A HURRICANE ON WEDNESDAY. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS. IKE IS STEERED BY A MID-LEVEL HIGH THAT WILL
MOVE WEST IN TANDEM WITH THE CYCLONE. SATELLITE IMAGERY SHOWS
THAT IKE HAS A COMPACT AND WELL-DEFINED CIRCULATION ALTHOUGH
DEEP CONVECTIVE BANDING HAS PRIMARILY BEEN LIMITED TO THE
EASTERN SEMICIRCLE.

TENTH TROPICAL DEPRESSION OF THE SEASON DEVELOPED OVER THE FAR
EASTERN ATLANTIC OCEAN EARLY THIS MORNING...AND SIX HOURS LATER
WAS UPGRADED TO TROPICAL STORM JOSEPHINE. AT 02/1500 UTC...ITS
CENTER IS NEAR 13.2N 25.3W OR ABOUT 110 NM...205 KM...
SOUTH-SOUTHWEST OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING
WEST AT 13 KT. A GENERAL W-NW MOTION AT ABOUT THE SAME FORWARD
SPEED IS FORECAST DURING THE NEXT COUPLE OF DAYS. JOSEPHINE WILL
CONTINUE TO PASS JUST SOUTH OF THE CAPE VERDE ISLANDS TODAY AND
TONIGHT...AND OVER THE OPEN WATERS OF THE EASTERN TROPICAL
ATLANTIC ON WEDNESDAY AND THURSDAY. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH
GUSTS TO 45 KT. STRENGTHENING IS FORECAST DURING THE NEXT COUPLE
OF DAYS...AND JOSEPHINE COULD BE NEAR HURRICANE STRENGTH ON
WEDNESDAY OR THURSDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.
VISIBLE IMAGERY REVEALS AN INCREASE IN THE CYCLONE'S
ORGANIZATION...WITH VERY WELL-DEFINED CONVECTIVE BANDS AND AN
EYE-LIKE FEATURE.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 60W/61W S OF 20N MOVING W 15-20 KT.
THIS SYSTEM IS PRODUCING SCATTERED MODERATE CONVECTION ACROSS
THE LESSER ANTILLES AND THE SURROUNDING COASTAL WATERS. MOISTURE
ASSOCIATED WITH THIS TROPICAL WAVE IS FORECAST BY THE COMPUTER
MODEL TO MOVE MAINLY NWD.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 13N17W 10N30W 9N40W 10N50W
9N60W. BESIDES THE CONVECTION MENTIONED IN THE SPECIAL FEATURES
SECTION REGARDING THE TROPICAL SYSTEMS...A LARGE CLUSTER OF
MODERATE TO STRONG CONVECTION IS APPROACHING THE WEST COAST OF
AFRICA...LIKELY ASSOCIATED WITH THE NEXT TROPICAL WAVE.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-10N
EAST OF 17W TO THE AFRICAN COAST.

...DISCUSSION...

GULF OF MEXICO...
A WEAK RIDGE IS BUILDING ACROSS THE GULF IN THE HEELS OF T.D
GUSTAV THAT IS INLAND OVER LOUISIANA. DOPPLER RADAR IS STILL
SHOWING THE OVERALL CIRCULATION OF GUSTAV WITH WELL DEFINED
RAINBANDS...THE STRONGEST ONES ARE TO THE EAST OF THE CENTER
AFFECTING MISSISSIPPI AND SE LOUISIANA AS WELL AS THE FAR
NORTH-CENTRAL WATERS OF THE GULF. SHOWERS WITH EMBEDDED TSTMS
ARE MOVING ACROSS THE STATE OF FLORIDA UNDER AN ELY WIND FLOW.
ALOFT...BROAD UPPER-LEVEL RIDGE ANCHORED ON AN UPPER HIGH
LOCATED OVER THE SE GULF NEAR 24N87W DOMINATES THE ENTIRE AREA.
UPPER DIFFLUENCE ASSOCIATED WITH THIS UPPER HIGH IS HELPING TO
INDUCE A SMALL AREA OF SHOWERS AND TSTMS NEAR 24N90W.

CARIBBEAN SEA...
MODERATE TO STRONG CONVECTION ASSOCIATED WITH HANNA IS SEEN OVER
HISPANIOLA AND REGIONAL COASTAL WATERS. NARROW RAINBANDS ON THE
WESTERN SIDE OF THE STORM ARE MOVING OVER EASTERN CUBA. A SECOND
CLUSTER OF MODERATE TO STRONG CONVECTION HAS DEVELOPED JUST
SOUTH OF HAITI WITH SOME SHOWER ACTIVITY ALSO OVER JAMAICA AND
THE SURROUNDING COASTAL WATERS. UPPER DIFFLUENCE BETWEEN THE
UPPER HIGH OVER THE SE PORTION OF THE GULF OF MEXICO AND AN
UPPER-LEVEL TROUGH OVER THE W ATLC IS ENHANCING ALL THIS
ACTIVITY. A TROPICAL WAVE IS GENERATING SCATTRED SHOWERS AND
TSTMS OVER THE LESSER ANTILLES. UNUSUAL WEST WINDS ARE NOTED
OVER THE CARIBBEAN SEA DUE TO THE LARGE CIRCULATION OF HANNA.

ATLANTIC OCEAN...
THREE TROPICAL STORMS ARE OVER THE FORECAST AREA...FROM EAST TO
WEST...JOSEPHINE...IKE AND HANNA. SEE SPECIAL FEATURES ABOVE FOR
DETAILS. UPPER RIDGE CENTERED IN THE SE GULF OF MEXICO EXTENDS
INTO THE W ATLC W OF 73W. BROAD UPPER LEVEL TROUGHING IS ACROSS
THE W ATLC N OF 24N BETWEEN 60W-73W. A LARGE UPPER LEVEL HIGH
CENTERED NEAR 29N40W EXTENDS A RIDGE SWD INTO THE TROPICAL ATLC
REACHING 10N. AN UPPER-LEVEL TROUGH EXTENDS SW ACROSS THE E ATLC
FROM AN UPPER-LEVEL LOW LOCATED NEAR B29N18W. UPPER-LEVEL ELY
WINDS DOMINATES MOST OF THE DEEP TROPICS. AT THE SURFACE...A
1026 MB HIGH IS SW OF THE AZORES NEAR 35N35W EXTENDING A RIDGE
OVER PARTS OF THE CENTRAL AND ERN ATLC.

$$
GR






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