[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 242354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUN 24 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 53W/54W S OF 12N MOVING W NEAR 15 KT.
THIS WAVE IS ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE
BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS.
SATELLITE IMAGERY INDICATES THE WAVE COINCIDES WITH AN
INVERTED-V CLOUD PATTERN IN THE LOW-LEVEL CLOUDS. SCATTERED
MODERATE CONVECTION IS FROM 7N-12N BETWEEN 48W-57W.

A TROPICAL WAVE EXTENDS ALONG 20N68W 15N70W 9N71W MOVING W NEAR
15 KT. THIS WAVE IS ASSOCIATED WITH A WELL-DEFINED MAXIMUM IN
DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER
PRODUCT FROM CIMSS WITH CYCLONIC CURVATURE NOTED IN THE LOW
LEVEL CLOUD FIELD ACROSS THE CENTRAL CARIBBEAN. THIS WAVE IS
BEING AMPLIFIED NWD AS IT ENCOUNTERS SELY FLOW ACROSS THE NE
CARIBBEAN DRIVEN BY A SURFACE TROUGH LOCATED IN THE SW NORTH
ATLC. STABLE ATMOSPHERIC CONDITIONS ARE LOCATED IN THE VICINITY
OF THE WAVE BENEATH A BROAD UPPER LEVEL RIDGE OVER THE CARIBBEAN
BASIN WHICH IS INHIBITING ANY DEEP CONVECTION NEAR THIS WAVE.
HOWEVER...SCATTERED SHOWERS ARE OCCURRING WITHIN 30 NM OF A LINE
FROM 19N68W TO 16N72W...INCLUDING PORTIONS OF FAR ERN HISPANIOLA.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 10N20W 6N33W 7N50W 8N55W
AND INTO GUYANA NEAR 7N59W. SCATTERED MODERATE TO STRONG
CONVECTION IS LOCATED INLAND ACROSS W AFRICA AND NEARBY COASTAL
WATERS FROM 4N-13N BETWEEN 6W-14W. SCATTERED MODERATE CONVECTION
IS WITHIN 60 NM OF A LINE FROM 12N19W TO 6N32W.

...DISCUSSION...

GULF OF MEXICO...
LOW LEVEL CONVERGENCE ASSOCIATED WITH A 1009 MB SURFACE LOW OVER
THE FAR W GULF NEAR 24N98W IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS OVER INTERIOR AND COASTAL NE MEXICO FROM
22N-26N W OF 97W. THIS ACTIVITY IS ALSO BEING SUPPORTED BY
ATMOSPHERIC INSTABILITY ASSOCIATED WITH UPPER LEVEL TROUGHING
OVER NRN MEXICO. ALSO...A SURFACE TROUGH ASSOCIATED WITH A DEEP
LAYER TROUGH OVER THE W ATLC...FLORIDA PENINSULA AND SE GULF IS
AFFECTING PORTIONS OF THE E GULF. THE SURFACE TROUGH EXTENDS
ACROSS FLORIDA FROM WEST PALM BEACH TO PORT CHARLOTTE AND INTO
THE NE GULF ALONG 28N85W TO A 1009 MB SURFACE LOW CENTERED NEAR
BILOXI MISSISSIPPI. LOW LEVEL CONFLUENCE NEAR THE SURFACE
TROUGH...ALONG WITH UPPER LEVEL DIFFLUENCE IN NLY FLOW ALOFT...
ARE SUPPORTING NUMEROUS SHOWERS AND ISOLATED TSTMS FROM 23N-28N
BETWEEN 80W-90W. ANOTHER AREA OF SCATTERED SHOWERS AND TSTMS ARE
ACROSS SRN LOUISIANA AND REMAIN N OF 29N IN THE N/CENTRAL GULF
WATERS. BETWEEN THE TWO AFOREMENTIONED AREAS OF SHOWERS AND
TSTMS...SUBSIDENCE AND DEEP LAYER DRY AIR IS OBSERVED ON WATER
VAPOR IMAGERY ACROSS PORTIONS OF THE WRN AND FAR NERN GULF...
RESULTING IN GENERALLY FAIR WEATHER. THIS SUBSIDENCE IS
SUPPORTING A 1013 MB SURFACE HIGH CENTERED NEAR 24N88W.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE IS AFFECTING MUCH OF THE CARIBBEAN.
UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS RIDGE IS COMBINING
WITH DEEP LAYER MOISTURE OVER THE SW CARIBBEAN TO RESULT IN
SCATTERED SHOWERS AND TSTMS S OF A LINE FROM 12N73W TO 15N84W...
INCLUDING PORTIONS OF NICARAGUA...COSTA RICA AND PANAMA. ACROSS
THE NW CARIBBEAN...SUBSIDENCE IN NLY FLOW ALOFT AND OVERALL DEEP
LAYER DRY AIR ARE RESULTING IN GENERALLY FAIR WEATHER. AS THE
TROPICAL WAVE MOVES ACROSS THE CENTRAL AND WRN CARIBBEAN...
EXPECT INCREASED SHOWER AND TSTM ACTIVITY W OF 70W AND AN
INCREASE IN ELY TRADE WINDS BEHIND THE WAVE AXIS THROUGH EARLY
FRIDAY.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH OVER THE W ATLC...FLORIDA PENINSULA AND ERN
GULF OF MEXICO IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING
ALONG 31N68W 27N74W ACROSS THE NW BAHAMAS TO THE SE FLORIDA
PENINSULA NEAR WEST PALM BEACH. LOW LEVEL CONVERGENCE NEAR THE
SURFACE TROUGH...AS WELL AS ATMOSPHERIC INSTABILITY...UPPER
LEVEL DIFFLUENCE...AND ABUNDANT DEEP LAYER MOISTURE...ARE
SUPPORTING SCATTERED SHOWERS AND TSTMS N OF 24N BETWEEN 60W-75W
AND FROM 21N-27N BETWEEN 75W-81W INCLUDING PORTIONS OF THE NRN
COAST OF CUBA...THE BAHAMAS AND THE TURKS AND CAICOS ISLANDS.
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 ANCHORED BY A 1028 MB SURFACE HIGH NEAR
35N49W. ACROSS THE TROPICAL ATLC...UPPER LEVEL RIDGING EXTENDS
ALONG 13N16W 7N34W TO 9N44W AND IS RESULTING IN THE CONVECTION
ASSOCIATED WITH THE ITCZ.

$$
HUFFMAN




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