[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 042338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT 04 SEP 2004

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

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

...SPECIAL FEATURES...
HURRICANE FRANCES AT 5PM EDT/2100 UTC...IS NEAR 26.9N 79.3W.
FRANCES IS MOVING WEST NORTHWEST AT 4 KT. THE CURRENT POSITION
IS ABOUT 50 MILES... 80 KM...EAST-NORTHEAST OF PALM BEACH
FLORIDA.  MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO
110 KT. THE LATEST MINIMUM CENTRAL PRESSURE MEASURED IS 951 MB.
EYE DIAMETER IS 60 NM...AND GETTING SMALLER...INDICATING
INTENSIFICATION.  SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT1/ WTNT31 KNHC AND THE FORECAST/ ADVISORY UNDER
HEADERS MIATCMAT1/WTNT21 KNHC FOR ADDITIONAL INFORMATION.
NUMEROUS STRONG CONVECTION IS NOTED IN SEVERAL BANDS OVER THE N
SEMICIRCLE. THE WESTERN MOST BANDS ARE ONSHORE OVER THE FLORIDA
E COAST.  SCATTERED MODERATE CONVECTION EXTENDS FROM 24N-30N
BETWEEN 75W-81W.

TROPICAL STORM IVAN IS CENTERED NEAR 9.1N 40.8W AT 04/2100 UTC
MOVING W AT 17 KT. THE MAXIMUM SUSTAINED WIND SPEED IS 50 KT
WITH GUSTS TO 60 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 994
MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.  UPPER LEVEL CONDITIONS
REMAIN FAVORABLE FOR CONTINUED STRENGTHENING OF IVAN TO
HURRICANE STATUS IN ABOUT 24 HOURS.  SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS FROM 7N-11N BETWEEN 37W-44W.

...TROPICAL WAVES...

LOW PRES...ABOUT 1013 MB...CONTINUES NEAR 26N46W...ORIGINALLY
SPAWNED ALONG THE NORTHERN EXTENSION OF A HIGH LATITUDE TROPICAL
WAVE THAT IS CURRENTLY ANALYZED AS A TROUGH EXTENDING FROM
31N45W TO 18N48W. THIS LOW LEVEL SYSTEM IS DRIFTING W UNDER A
TROPICAL UPPER TROUGH RESULTING IN SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION FROM 27N-29N BETWEEN 40W-45W. THE
CONVECTION IS SHEARED WELL TO THE NE OF THE EXPOSED LOW LEVEL
CIRCULATION CENTER. GUIDANCE MOVES THE LOW PRES N TO NEAR 30N47W
IN 24 HOURS.

TROPICAL WAVE IS ALONG 73W S OF 18N MOVING W ABOUT 12 KT. THE
WAVE AXIS IS DIFFICULT TO ACCURATELY LOCATE AS BROAD CYCLONIC
TURNING CONTINUES IN THE TRADE WIND CUMULUS MOVING W THROUGH THE
CENTRAL CARIBBEAN WATERS. ADDITIONALLY...WIDESPREAD CONVECTION
OVER VENEZUELA AND COLOMBIA IS MASKING THE WAVE AXIS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N10W 7N25W 9N40W 6N57W 10N73W
10N80W. OTHER THAN T.S. IVAN CONVECTION...ISOLATED MODERATE
CONVECTION IS FROM 4N-7N BETWEEN 28W-31W.  SCATTERED MODERATE
AND ISOLATED STRONG CONVECTION IS OBSERVED OVER S AMERICA FROM
3N-11N BETWEEN 59W-76W.

...DISCUSSION...

GULF OF MEXICO...
TWO SMALL CYCLONIC CIRCULATIONS ARE OVER S TEXAS AND THE W GULF
OF MEXICO NEAR 29N99W...AND 22N98W.  AN ANTICYCLONIC CIRCULATION
IS OVER W CUBA NEAR 21N82W PRODUCING SOME WESTERLY SHEAR ONTO
HURRICANE FRANCES.  THE MOISTURE PLUME ASSOCIATED WITH HURRICANE
FRANCES IS SPREADING W ACROSS FLORIDA E OF 83W.

CARIBBEAN SEA...
THE ANTICYCLONIC CIRCULATION OVER W CUBA IS PRODUCING
ANTICYCLONIC FLOW OVER THE WESTERN CARIBBEAN W OF 72W.  A
CYCLONIC CIRCULATION IS OVER THE E CARIBBEAN NEAR 14N63W.
CYCLONIC FLOW IS E OF 72W.

SUBTROPICAL ATLANTIC...
THE CENTRAL AND EASTERN SUBTROPICAL ATLANTIC HAS A TROUGH...
RIDGE...TROUGH PATTERN WITH EMBEDDED CIRCULATIONS.  TWO CYCLONIC
CIRCULATIONS ARE AT 27N53W...AND 20N59W.   TWO ANTICYCLONIC
CIRCULATIONS ARE AT 28N40W...AND 20N48W.  TWO  MORE CYCLONIC
CIRCULATIONS ARE AT 40N10W...AND 27N28W.

TROPICAL ATLANTIC...
A LARGE ANTICYCLONIC CIRCULATION IS OVER W AFRICA NEAR 17N8W.
ANTICYCLONIC FLOW IS FROM 7N-30N E OF 20W.  ANTICYCLONIC FLOW IS
OVER T.S. IVAN FROM 1N-20N BETWEEN 30W-50W.

$$
FORMOSA


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