[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 042357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM 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.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM HANNA IS CENTERED NEAR 26.0N 76.0W AT 05/0000 UTC
OR ABOUT 65 NM EAST-SOUTHEAST OF MARSH HARBOR IN THE BAHAMAS AND
ABOUT 500 NM SOUTH-SOUTHEAST OF WILMINGTON NORTH CAROLINA MOVING
NW AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB.
MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SEE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/
WTNT23 KNHC FOR MORE DETAILS. HANNA IS EXPECTED TO TRACK NW
DURING THE NEXT DAY OR SO WITH A GRADUAL INCREASE IN FORWARD
SPEED. A TURN TO THE NORTH IS EXPECTED BY LATE FRIDAY. THE
CENTER OF HANNA WILL PASS JUST EAST OF THE CENTRAL AND
NORTHWESTERN BAHAMAS TONIGHT...AND WILL BE NEAR THE SOUTHEAST
COAST OF THE UNITED STATES BY LATE FRIDAY. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS EAST OF ABACO ISLAND BAHAMAS FROM
26N-28N BETWEEN 75W-77W. WIDELY SCATTERED SHOWERS COVER THE
REMAINDER OF THE AREA FROM 25N-29N BETWEEN 75W-81W...INCLUDING
THE SERN FLORIDA PENINSULA. AN UPPER LOW CENTERED OVER WRN CUBA
IS WRAPPING DRY AIR AROUND THE SRN PERIPHERY OF HANNA...THUS
LIMITING CONVECTION S OF 25N.

HURRICANE IKE IS CENTERED NEAR 23.6N 58.2W AT 04/2100 UTC OR
ABOUT 435 NM NORTH-NORTHEAST OF THE LEEWARD ISLANDS MOVING W-NW
AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 945 MB. MAXIMUM
SUSTAINED WIND SPEED IS 115 KT WITH HIGHER GUSTS. IKE IS A
EXTREMELY DANGEROUS CATEGORY FOUR HURRICANE ON THE SAFFIR-
SIMPSON HURRICANE SCALE. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. A
GRADUAL TURN TOWARD THE WEST AND WEST-SOUTHWEST IS EXPECTED OVER
THE NEXT 48 HOURS AND IKE WILL CONTINUE TO MOVE OVER THE OPEN
WATERS OF THE W/CENTRAL ATLC DURING THE NEXT COUPLE OF DAYS. IKE
CONTINUES TO EXHIBIT AN IMPRESSIVE SATELLITE PRESENTATION WITH A
WELL-DEFINED EYE AND GOOD OUTFLOW IN ALL QUADRANTS AS IT MOVES
ALONG THE SRN PERIPHERY OF A CENTRAL ATLC UPPER LEVEL HIGH.
NUMEROUS STRONG CONVECTION IS LOCATED WITHIN 90 NM OF THE CENTER
IN THE SE QUADRANT AND 60 NM OF THE CENTER ALL OTHER QUADRANTS.
SCATTERED MODERATE CONVECTION COVERS THE REMAINDER OF THE AREA
FROM 21N-25N BETWEEN 55W-61W.

TROPICAL STORM JOSEPHINE IS CENTERED NEAR 14.6N 33.2W AT 04/2100
UTC OR ABOUT 510 NM WEST OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MOVING W-NW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002
MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. UPPER-LEVEL WINDS ARE
CURRENTLY NOT FAVORABLE FOR SIGNIFICANT STRENGTHENING AND LITTLE
CHANGE IN STRENGTH IS FORECAST DURING THE NEXT COUPLE OF DAYS.
SCATTERED MODERATE CONVECTION IS FROM 16N-18N BETWEEN 30W-33W
AND REMAINS WELL NORTH OF THE CIRCULATION CENTER.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 20W S OF 19N MOVING W NEAR 10 KT.
SATELLITE IMAGERY SHOWS MODERATE CYCLONIC CURVATURE N OF 14N
WITH SCATTERED SHOWERS COVERING THE AREA FROM 15N-20N EAST OF
21W TO THE W AFRICAN COAST. THE LEADING EDGE OF ISOLATED SHOWERS
HAVE REACHED THE EASTERNMOST CAPE VERDE ISLANDS.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 43W S OF 16N MOVING W NEAR
10-15 KT. A LARGE AREA OF CLOUDINESS WITH EMBEDDED SCATTERED
SHOWERS COVER THE AREA FROM 10N-16N BETWEEN 42W-46W.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 13N22W 13N28W 11N36W 12N43W
11N47W 8N56W 9N62W...DISRUPTED BY THE TWO TROPICAL WAVE AND T.S.
JOSEPHINE. ISOLATED MODERATE CONVECTION IS FROM 6N-9N BETWEEN
43W-52W AND FROM 11N-14N BETWEEN 46W-52W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD LONGWAVE TROUGH IS ACROSS THE CENTRAL CONUS WITH A
SURFACE COLD FRONT ENTERING THE GULF OF MEXICO NEAR VERMILION
BAY LOUISIANA EXTENDING TO EAST OF BROWNSVILLE TEXAS. A NARROW
BAND OF MOISTURE IN THE FORM OF MULTILAYERED CLOUDINESS IS
OBSERVED ON SATELLITE IMAGERY THIS EVENING. ISOLATED SHOWERS AND
TSTMS ARE E OF THE FRONT ACROSS THE CENTRAL GULF N OF 25N
BETWEEN 89W-92W. ANOTHER SURFACE TROUGH IS LOCATED OVER THE SW
GULF AND BAY OF CAMPECHE...RESULTING IN SCATTERED SHOWERS AND
TSTMS S OF 21N...BETWEEN THE YUCATAN PENINSULA AND 97W. A WEAK
SURFACE RIDGE EXTENDS FROM THE FLORIDA PANHANDLE TO NEAR 24N90W.
AN UPPER RIDGE ASSOCIATED WITH T.S. HANNA IN THE W ATLC IS
SPREADING MID-HIGH LEVEL CLOUDINESS OVER THE FLORIDA PENINSULA
THIS EVENING WITH ISOLATED SHOWERS ACROSS THE SE PORTION OF THE
PENINSULA. AN UPPER LEVEL HIGH IS OVER THE SRN BAJA PENINSULA
AND W/CENTRAL MEXICO WITH ITS ASSOCIATED RIDGE ACROSS MUCH OF
THE GULF W OF 94W. AN UPPER LEVEL LOW CENTERED OVER WRN CUBA IS
PRODUCING DRY NLY UPPER LEVEL FLOW OVER THE SE GULF.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE EXTENDS SW FROM AN UPPER LEVEL HIGH OVER
THE W/CENTRAL ATLC. THIS COMBINED WITH THE AFOREMENTIONED UPPER
LEVEL LOW OVER WRN CUBA IS RESULTING IN A LARGE AREA OF
SCATTERED MODERATE CONVECTION OVER THE CENTRAL CARIBBEAN FROM
NRN COLOMBIA TO 21N BETWEEN 68W-75W...INCLUDING HISPANIOLA...THE
MONA AND WINDWARD PASSAGES. THE SAN JUAN DOPPLER RADAR ALSO
INDICATES SCATTERED SHOWERS AND TSTMS IN THEIR VICINITY. DRY ELY
UPPER LEVEL FLOW COMBINED WITH MODERATE TO STRONG SUBSIDENCE/DRY
AIR IS ACROSS THE ERN CARIBBEAN E OF A LINE FROM THE VIRGIN
ISLANDS TO NEAR ARUBA LIMITING ANY PRECIPITATION THIS EVENING.

ATLANTIC OCEAN...
THREE TROPICAL CYCLONES ARE LOCATED IN THE DISCUSSION AREA...SEE
SPECIAL FEATURES ABOVE FOR DETAILS. AN UPPER LEVEL HIGH IS OVER
THE WEST AND CENTRAL ATLC CENTERED NEAR 30N65W AND EXTENDS A
RIDGE AXIS OVER THE ERN GREATER ANTILLES TO THE SW AND A RIDGE
AXIS OVER THE MID-ATLANTIC STATES TO THE NW. AN UPPER LEVEL LOW
IS CENTERED NEAR 19N43W. UPPER DIFFLUENCE E OF THIS UPPER LOW IS
LOCATED NORTH OF THE TROPICAL WAVE ALONG 43W AND IS GENERATING
SCATTERED SHOWERS FROM 15N-18N BETWEEN 40W-43W. THE REMAINDER OF
THE FORECAST AREA IS DOMINATED BY AN UPPER LEVEL RIDGE OVER THE
WRN COAST OF AFRICA NEAR 21N13W. AT THE SURFACE...A 1025 MB HIGH
CENTERED NORTH OF THE AREA NEAR 36N46W COVERS THE ERN AND
CENTRAL ATLC N OF 23N AND E OF 54W.

$$
HUFFMAN




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