[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 030617
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI 03 SEP 2004

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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0345 UTC.

...SPECIAL FEATURES...

THE EYE OF CATEGORY THREE HURRICANE FRANCES AT 2 AM
EDT...0600Z...WAS LOCATED BY RECONNAISSANCE AIRCRAFT AND RADAR
NEAR LATITUDE 24.7 NORTH...LONGITUDE  75.7 WEST OR NEAR THE
NORTHERN END OF CAT ISLAND. THIS IS ALSO ABOUT 310 MILES...
495 KM...EAST-SOUTHEAST OF THE FLORIDA LOWER EAST COAST.
MAXIMUM SUSTAINED WIND SPEED HAS DECREASED JUST A BIT TO 110 KT
WITH GUSTS TO 135 KT. MINIMUM CENTRAL PRESSURE REPORTED FROM A
RECONNAISSANCE AIRPLANE IS 948 MB. SEE LATEST NHC PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE
FORECAST/ADVISORY UNDER HEADERS MIATCMAT1/WTNT21 KNHC FOR
ADDITIONAL INFORMATION. FRANCES CONTINUES MOVING ACROSS THE
EASTERN BAHAMA ISLANDS. AN AREA OF UPPER LEVEL DRY AIR IS
IMMEDIATELY TO THE WEST OF THE AREA OF THE HURRICANE. SOME UPPER
LEVEL SHEARING WINDS HAVE CUT INTO THE CIRCULATION A LITTLE BIT
ALSO. THE EYE BECAME A LITTLE RAGGED AND OBSCURED AS IT PASSED
OVER SAN SALVADOR YESTERDAY...BUT IT IS NOT CERTAIN AT THIS TIME
IF THE HURRICANE IS WEAKENING A BIT OR IT IS JUST GOING THROUGH
ANOTHER EYEWALL REPLACEMENT CYCLE. ONE ENCOURAGING NOTE...THE
AIRCRAFT RECONNAISSANCE FROM YESTERDAY AFTERNOON FOUND A HIGHER
CENTRAL PRESSURE AND SLIGHTLY WEAKER WINDS SO IT WILL BE
INTERESTING TO SEE IF THIS TREND CONTINUES. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS FROM 23.5N TO 25.5N BETWEEN 73.5 AND
76W. THE HURRICANE HAS BEEN WOBBLING A LITTLE ALONG ITS FORECAST
TRACK AND THIS IS EXPECTED AS THE HURRICANE CONTINUES TO MOVE
ACROSS THE BAHAMAS AND TOWARDS THE FLORIDA COAST. REMEMBER THAT
ANY OF THESE WOBBLES COULD BRING THE HURRICANE INLAND ANYWHERE
ALONG THE WARNING AREA. RESIDENTS IN EVACUATION ZONES AND IN
MOBILE HOMES WITHIN THE WARNING AREA ARE URGED TO FOLLOW THE
DIRECTION OF LOCAL COUNTY EMERGENCY MANAGERS.

TROPICAL DEPRESSION NINE CENTER NEAR 9.8N 29.4W AT 03/0300 UTC
MOVING WEST 14 KT. MAXIMUM SUSTAINED WIND SPEED 25 KT GUSTS
35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS
FROM 8N TO 11N BETWEEN 29W AND 33W...AND SCATTERED STRONG SHOWERS
AND THUNDERSTORMS FROM 7.5N TO 10N BETWEEN 33W AND 35W.

...TROPICAL WAVES...

TROPICAL WAVE 25N40W TO 1013 MB LOW PRESSURE CENTER NEAR
19N42W...TO 8N43W...MOVING WEST 10 TO 15 KT. SCATTERED TO
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 22N TO 25N
BETWEEN 39W AND 42W.

TROPICAL WAVE 24N61W 13N63W 7N63W...MOVING WEST 10 TO 15 KT.
SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS IN
VENEZUELA FROM 8.5N TO 10N BETWEEN 64W AND 66W MAY BE ENHANCED
BY THIS WAVE AND THE ITCZ. THE WAVE IS BECOMING INCREASINGLY
INFLUENCED BY NORTHWEST-TO-WEST SHEAR AS A LARGE UPPER LEVEL
CYCLONIC CIRCULATION CENTER ROTATES WESTWARD IN THE DIRECTION
OF THE NORTHERN LEEWARD ISLANDS. DRY AIR NEAR THIS CYCLONIC
CENTER IS LIMITING DEEP CONVECTIVE ACTIVITY...WHICH IS PRIMARILY
RESTRICTED SOUTHEAST OF BARBADOS NEAR THE ITCZ.

...ITCZ...

ITCZ 15N17W 12N26W 8N31W 10N42W 10N45W 8N60W...AND IN THE
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA FROM 8N77W IN COLOMBIA
TO 9N83W IN PANAMA. WIDELY SCATTERED TO SCATTERED MODERATE/
ISOLATED STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO 15N
BETWEEN 52W AND 58W...TO THE SOUTH OF A MIDDLE TO UPPER LEVEL
TROUGH. WIDELY SCATTERED MODERATE TO ISOLATED STRONG SHOWERS
AND THUNDERSTORMS ARE IMMEDIATELY SOUTH OF THE TROUGH...NORTH
OF THE ITCZ...FROM 16N TO 19N BETWEEN 52W AND 60W. ISOLATED
MODERATE SHOWERS AND THUNDERSTORMS FROM 5N TO 10N BETWEEN
AFRICA COAST AND 24W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE CONTINUES FROM WESTERN MEXICO NEAR
20N105W TO THE DEEP SOUTH TEXAS TO EAST CENTRAL LOUISIANA AND
BEYOND. A STRETCHED-OUT MIDDLE TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS NOW IN THE SOUTHWESTERN CORNER OF THE AREA
JUST WEST OF THE YUCATAN PENINSULA. UPPER LEVEL DRY AIR STRETCHES
FROM THE NORTH CENTRAL CUBA COAST TO 30N80W BETWEEN 78W AND
82W MAY INFLUENCE THE BEHAVIOR OF HURRICANE FRANCES IN THE NEAR
FUTURE.

CARIBBEAN...
THE UPPER LEVEL ANTICYCLONIC OUTFLOW WITH FRANCES REACHES
THE CARIBBEAN WATERS...NORTH OF 14N BETWEEN 67W AND 82W.
THIS UPPER LEVEL ANTICYCLONIC OUTFLOW IS MOVING OVER THE TOP OF
AT LEAST MIDDLE LEVEL DRY AIR FIRMLY ENTRENCHED IN THE CARIBBEAN
AREA. THE EASTERN CARIBBEAN SEA...EAST OF 70W...IS DOMINATED BY
CYCLONIC FLOW FROM THE BASE OF A MIDDLE TO UPPER LEVEL TROUGH.

REMAINDER OF SUBTROPICAL ATLANTIC...
A COUPLET OF MID/UPPER LOWS ARE CENTERED NE OF THE NRN LEEWARD
ISLANDS NEAR 20N56W AND 29N47W AND ARE COMBINING FORCES TO DRAW
DEEP MOISTURE NWD OVER THE CNTRL ATLC AND DRIER AIR SWD BETWEEN
50W-66W. IN ADDITION...THE STRONG SLY FLOW TO THE E OF THE LOWS
IS PRODUCING STRONG VERTICAL SHEAR OVER THE TROPICAL WAVE/LOW
ALONG 42W...AND THIS HAS PREVENTED THE SYSTEM FROM DEVELOPING
INTO A TROPICAL DEPRESSION. TO THE E...A WELL-DEFINED UPPER
LEVEL HIGH HAS DEVELOPED NEAR 19N34W AND DEEP-LAYERED TROUGHING
IS PLUNGING FROM THE COAST OF PORTUGAL SWD PAST THE CANARY
ISLANDS TO 24N. THIS TROF IS SUPPORTING A COLD FRONT WHICH LIES
ALONG THE COAST OF MOROCCO THEN WWD TO 31N20W.

TROPICAL ATLANTIC...
THE UPPER LOW CENTERED NE OF THE LEEWARD ISLANDS NEAR 19N56W IS
PRODUCING STRONG WLY UPPER FLOW FROM THE WINDWARD ISLANDS EWD TO
45W...WHICH WILL KEEP THIS AREA OF THE ATLC NON-CONDUCIVE FOR
TROPICAL DEVELOPMENT. HOWEVER...STRONG RIDGING AND DEEP-LAYERED
ELY FLOW OVER THE E ATLC HAS PROMPTED THE DEVELOPMENT OF
TROPICAL DEPRESSION NINE JUST SW OF THE CAPE VERDE ISLANDS. THIS
RIDGE IS EXPECTED TO EXPAND WWD ACROSS THE ATLC AND WILL MAKE
THE ENVIRONMENT NEAR THE LESSER ANTILLES CONDUCIVE FOR FURTHER
STRENGTHENING OF THE DEPRESSION. FARTHER E...A SQUALL LINE HAS
DEVELOPED OVER PARTS OF W AFRICA EXTENDING FROM SE MAURITANIA TO
THE GUINEA/IVORY COAST LINE...AND SOME OF THESE STORMS MAY
APPROACH THE ATLC WATERS LATER TONIGHT OR TOMORROW.

$$
BERG


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