[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 11 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 ALONG 14N51W TO 3N54W IS MOVING W NEAR 15 KT.
THIS HIGH AMPLITUDE WAVE HAS GAINED CONVECTION TODAY AS IT MOVED
INTO AN UPPER DIFFLUENT ZONE. SCATTERED MODERATE CONVECTION IS
WITHIN 120 NM W AND 300 NM E OF THE AXIS.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N24W 3N34W 3N45W 4N52W.
SCATTERED MODERATE TO STRONG CONVECTION FROM 5N TO 10N BETWEEN
12W-25W. SCATTERED MODERATE CONVECTION IS FROM 2N-6N BETWEEN
27W-33W. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN
39W-41W.

...DISCUSSION...

GULF OF MEXICO...
SFC HIGH PRES IS NEARLY STATIONARY CENTERED NEAR 27N87W PROVIDING
LIGHT AND VARIABLE FLOW E OF 90W. SE WINDS INCREASE W OF
90W...STRONGEST (15-20 KT) OVER THE NW WATERS...DUE TO THE TIGHTENED
PRES GRADIENT BETWEEN THE HIGH AND BROAD TROUGHING OVER S TEXAS AND
MEXICO. FAIR WEATHER IS PRESENT ACROSS THE ENTIRE GULF SUPPORTED BY
NLY FLOW ALOFT ON THE E SIDE OF A SPRAWLING MID-UPPER HIGH OVER
CENTRAL MEXICO. LITTLE CHANGE IN THIS PATTERN IS EXPECTED OVER THE
NEXT DAY OR TWO...SO MAINLY FAIR WEATHER IS FORECAST TO PERSIST.

CARIBBEAN SEA...
VISIBLE IMAGERY AND RECENT SCATTEROMETER DATA INDICATE BROAD SFC
TROUGHING OVER THE WRN CARIBBEAN WITH A ROUGH AXIS EXTENDING FROM
JAMAICA TO CENTRAL PANAMA. SFC OBSERVATIONS SHOW FAIRLY LOW
PRESSURES...GENERALLY ABOUT 1-2 MB LOWER THAN THIS TIME YESTERDAY.
SCATTERED MODERATE CONVECTION IS LOCATED TO THE E OF THE SFC
TROUGH...WITHIN AN UPPER DIFFLUENT AREA E OF AN UPPER TROUGH AXIS
THAT EXTENDS FROM CENTRAL CUBA TO NICARAGUA. SCATTERED MODERATE
CONVECTION IS CURRENTLY LOCATED S OF 12N BETWEEN 75W-82W AND N OF
14N BETWEEN 72W AND 76W.  THE ERN CARIBBEAN IS EXPERIENCING FAIR
WEATHER...THOUGH SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER
PUERTO RICO AND THE VIRGIN ISLANDS ASSOCIATED WITH THE
AFOREMENTIONED DIFFLUENT ZONE. MOISTURE IS EXPECTED TO INCREASE OVER
THE LESSER ANTILLES LATE TOMORROW AND SAT AS A TROPICAL WAVE
APPROACHES THE AREA.

ATLANTIC OCEAN...
UPPER LEVEL DIFFLUENCE IN MOIST SOUTH-SOUTHWESTERLY FLOW ALOFT
ACROSS THE SW NORTH ATLC IS OCCURRING E OF AN UPPER LOW NE OF THE
BAHAMAS. THIS IS PROVIDING THE SUPPORT FOR SCATTERED SHOWERS AND
THUNDERSTORMS N OF 19N BETWEEN 62W-74W INCLUDING PORTIONS OF
HISPANIOLA. THIS ACTIVITY IS ALSO BEING SUPPORTED BY LOW LEVEL
CONVERGENCE NEAR A SURFACE TROUGH EXTENDING FROM 29N65W TO 29N74W.
THE ASCAT PASS AROUND 11/1400 UTC CONFIRMS A CYCLONIC WIND SHIFT
ACROSS THIS TROUGH. FARTHER TO THE W...SUBSIDENCE IN DRY NORTHERLY
FLOW ALOFT IS SUPPORTING GENERALLY FAIR WEATHER ACROSS WESTERN
PORTIONS OF THE SW NORTH ATLC. FARTHER TO THE E...GENERALLY FAIR
WEATHER IS PRESENT ACROSS MUCH OF THE CENTRAL AND E ATLC WHERE
SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. THIS SURFACE
RIDGE IS ANCHORED BY A 1025 MB SURFACE HIGH NEAR 29N36W.
HOWEVER...ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL
TROUGH WITH AN AXIS FROM 18N49W TO 27N36W TO 32N31W TO NE OF THE
DISCUSSION AREA IS SUPPORTING SCATTERED SHOWERS FROM 19N-23N BETWEEN
48W-52W AND N OF 25N BETWEEN 25W-31W. ACROSS THE TROPICAL ATLC...A
BROAD UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 12N24W. UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THIS FEATURE IS SUPPORTING CONVECTION
ASSOCIATED WITH THE ITCZ.

$$
CANGIALOSI/COHEN




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