[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE AUG 04 2009

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.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 25W S OF 17N MOVING W NEAR 10 KT.
SATELLITE IMAGERY INDICATES LOW-LEVEL CYCLONIC FLOW S OF THE
CAPE VERDE ISLANDS IN THE VICINITY OF THE WAVE AXIS. ALSO THE
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 12N-15N BETWEEN 24W-27W.

A TROPICAL WAVE EXTENDS ALONG 17N53W TO 9N49W MOVING W NEAR 18
KT. SATELLITE IMAGERY AND LOW-LEVEL CLOUD DRIFT WINDS INDICATE
CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. THIS WAVE ALSO
COINCIDES WITH A LOW-AMPLITUDE DEEP LAYER MOISTURE MAXIMUM IN
THE TOTAL PRECIPITABLE WATER IMAGERY. THIS WAVE IS ON THE
LEADING EDGE OF SAHARAN DUST WHICH IS INHIBITING DEEP CONVECTION
NEAR THE WAVE.

A TROPICAL WAVE IS ALONG 73W S OF 19N MOVING W NEAR 15-20 KT.
BROAD LOW-LEVEL CYCLONIC FLOW IS OVER THE WRN CARIBBEAN...WHILE
TOTAL PRECIPITABLE WATER IMAGERY INDICATES A BROAD AREA OF
INCREASED MOISTURE OVER THE WRN CARIBBEAN AS WELL. NO DEEP
CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 12N16W 12N23W 10N32W 10N40W
12N48W 12N51W 10N62W. SCATTERED MODERATE CONVECTION IS FROM
8N-11N BETWEEN 15W-22W. SIMILAR CONVECTION IS FOCUSED W OF A
SURFACE TROUGH ANALYZED ALONG 15N30W TO 6N30W. THE SCATTERED
MODERATE CONVECTION IS FROM 6N-12N BETWEEN 30W-41W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD SURFACE RIDGE IS ACROSS THE GULF OF MEXICO ANCHORED BY A
1019 MB SURFACE HIGH NEAR 29N92W BRINGING GENERALLY FAIR WEATHER
ACROSS THE AREA. HOWEVER...A SURFACE TROUGH IS ACROSS SE GEORGIA
AND NE FLORIDA TO NEAR TALLAHASSEE. LOW-LEVEL CONVERGENCE NEAR
THE SURFACE TROUGH ALONG WITH UPPER LEVEL DIFFLUENCE BETWEEN AN
UPPER LEVEL TROUGH OVER THE SE CONUS AND AN UPPER LEVEL HIGH
CENTERED OVER THE NW BAHAMAS NEAR 27N78W ARE SUPPORTING
SCATTERED SHOWERS AND TSTMS ACROSS INTERIOR FLORIDA N OF 26N AND
ACROSS THE FLORIDA PANHANDLE AND NEARBY COASTAL WATERS N OF 30N.
ANOTHER UPPER LEVEL ANTICYCLONE IS CENTERED OVER NRN MEXICO AND
EXTENDS ACROSS THE WRN GULF TO 85W. MIDDLE TO UPPER LEVEL
DIFFLUENCE IS SUPPORTING ISOLATED SHOWERS AND TSTMS FROM 25N-29N
BETWEEN 86W-95W. ALSO AN UPPER LEVEL INVERTED TROUGH IS OVER THE
YUCATAN PENINSULA AND SE GULF BRINGING SCATTERED SHOWERS AND
ISOLATED TSTMS TO THE YUCATAN CHANNEL AND PENINSULA. EXPECT THE
SURFACE RIDGE TO PERSIST ACROSS THE NRN GULF...AND A SURFACE
TROUGH OVER CENTRAL CUBA TO MOVE ACROSS THE STRAITS OF FLORIDA
AND SE GULF OVERNIGHT.

CARIBBEAN SEA...
UPPER LEVEL CYCLONIC FLOW ASSOCIATED WITH AN INVERTED TROUGH IS
OVER THE YUCATAN CHANNEL...CUBA AND HISPANIOLA. UPPER LEVEL
DIFFLUENCE AND LOW-LEVEL INSTABILITY AND CONVERGENCE ALONG A
SURFACE TROUGH EXTENDING FROM ANDROS ISLAND IN THE BAHAMAS TO
18N80W ARE FUELING SCATTERED SHOWERS AND TSTMS ACROSS CUBA...
JAMAICA AND HISPANIOLA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
ACROSS THE SW CARIBBEAN S OF 11N BETWEEN 79W-86W ENHANCED BY
SURFACE CONVERGENCE NEAR THE PROXIMITY OF THE E PACIFIC ITCZ AND
AN UPPER LEVEL DIFFLUENT PATTERN ACROSS CENTRAL AMERICA. ACROSS
THE REMAINDER OF THE CARIBBEAN...GENERALLY FAIR WEATHER IS
PRESENT DUE TO STRONG SUBSIDENCE ALOFT W OF UPPER LEVEL
TROUGHING EXTENDING FROM THE CENTRAL ATLC TO ACROSS THE NE
CARIBBEAN.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHING ACROSS THE SE CONUS SUPPORTS A PAIR OF
SURFACE TROUGHS...ONE EXTENDING ACROSS NE FLORIDA TO TALLAHASSEE
AND THE OTHER FARTHER E EXTENDING FROM 31N78W TO NE OF THE
DISCUSSION AREA. SURFACE CONVERGENCE NEAR THE SURFACE TROUGHS
AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL
ANTICYCLONE CENTERED OVER THE NW BAHAMAS NEAR 27N78W ARE
SUPPORTING SCATTERED SHOWERS AND TSTMS N OF 27N W OF 79W...AND
SCATTERED SHOWERS OVER THE W ATLC WATERS N OF 27N BETWEEN
68W-77W. ANOTHER SURFACE TROUGH...A FRACTURED PIECE OF ENERGY
FROM THE TROPICAL WAVE ALONG 51W EXTENDS FROM 18N57W TO 22N59W.
ISOLATED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE TROUGH
AXIS. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE EXTENDS
FROM THE W AFRICA COAST TO 66W AND IS ANCHORED BY A 1028 MB
SURFACE HIGH NEAR 36N49W BRINGING GENERALLY FAIR WEATHER. IN THE
UPPER LEVELS...AN UPPER LEVEL TROUGH IS BETWEEN 55W-68W CENTERED
NEAR 28N63W. A BROAD UPPER LEVEL RIDGE DOMINATES THE ERN ATLC
WITH AXIS EXTENDING FROM W AFRICA ALONG 17N TO 55W.

$$
HUFFMAN



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