[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041111
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED JUN 03 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 42W/43W S OF 16N MOVING W 10-15 KT.
THIS WAVE IS ASSOCIATED WITH A RATHER HIGHLY AMPLIFIED MAXIMUM
IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER
PRODUCT FROM CIMSS. SATELLITE IMAGERY INDICATES THAT THE WAVE
CORRESPONDS WITH A LARGE INVERTED-V SIGNATURE IN THE LOW LEVEL
CLOUD FIELD...WITH SATELLITE DERIVED WINDS INDICATING CYCLONIC
CURVATURE IN THE LOW LEVEL FLOW NEAR THIS WAVE. SCATTERED
MODERATE CONVECTION IS FROM 5N-9N BETWEEN 38W-43W. THE DEEP
LAYER MOISTURE ASSOCIATED WITH THE WAVE APPEARS TO BE AT THE
LEADING EDGE OF DRY LOW/MID-LEVEL SAHARAN AIR...WHICH IS FURTHER
ENHANCING THIS CONVECTION AND INCREASING THE POTENTIAL FOR GUSTY
WINDS WITH THE CONVECTION.

A TROPICAL WAVE IS OVER THE ALONG 81W/82W S OF 17N MOVING W
10-15 KT. THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS
INDICATES THAT THIS WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER
MOISTURE. SATELLITE IMAGERY INDICATES THAT THE WAVE ALSO
COINCIDES WITH AN INVERTED-V SIGNATURE IN THE LOW LEVEL CLOUD
FIELD. THE CIMSS WAVETRAK PRODUCT ALSO DEPICTS LOW LEVEL
CYCLONIC CIRCULATION NEAR THE WAVE. SCATTERED MODERATE
CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE WAVE AXIS S OF
12N.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N21W 4N33W 4N41W AND INTO
NE BRAZIL ALONG THE EQUATOR NEAR 51W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-9N BETWEEN
9W-16W AND FROM 1N-7N BETWEEN 20W-24W. SCATTERED MODERATE
CONVECTION IS FROM 3N-7N BETWEEN 29W-33W AND S OF 3N BETWEEN
44W-50W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH IS PRESENT ACROSS THE GULF REGION WITH AN
AXIS EXTENDING FROM 22N89W TO 26N90W TO 30N90W TO N OF THE
DISCUSSION AREA. ATMOSPHERIC INSTABILITY NEAR THE UPPER LEVEL
TROUGH...AND UPPER LEVEL DIFFLUENCE IN MOIST SOUTHWESTERLY FLOW
ALOFT E OF THE UPPER LEVEL TROUGH AXIS...ARE SUPPORTING
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE GULF N OF 22N E
OF 90W INCLUDING ADJACENT INLAND AREAS ALONG THE GULF COAST.
ALSO...LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH ACROSS THE NW
GULF EXTENDING FROM SW LOUISIANA NEAR 30N93W TO SE TEXAS NEAR
28N97W IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF
28N W OF 90W INCLUDING ADJACENT INLAND AREAS ALONG THE GULF
COAST. ACROSS THE SW GULF...DEEP LAYER DRY AIR AND SUBSIDENCE IN
NORTHWESTERLY FLOW ALOFT ARE SUPPORTING GENERALLY FAIR WEATHER.
THIS SUBSIDENCE IS BEING ENHANCED AROUND A 1015 MB SURFACE HIGH
NEAR 27N88W. THIS SURFACE HIGH IS FORECAST TO DISSIPATE DURING
THE NEXT DAY. THE AFOREMENTIONED UPPER LEVEL TROUGH IS
ASSOCIATED WITH A SURFACE STATIONARY FRONT OVER THE SOUTHERN
PLAINS OF THE UNITED STATES. THIS FRONT IS FORECAST TO MOVE
SOUTHEASTWARD ACROSS THE GULF AS A COLD FRONT DURING THE NEXT
TWO DAYS...AND EXTEND FROM THE FLORIDA BIG BEND TO S TEXAS BY
FRIDAY NIGHT. SW TO W WINDS OF 10 TO 15 KT WILL BE PRESENT AHEAD
OF THE FRONT ACROSS PORTIONS OF THE MIDDLE AND E GULF.

CARIBBEAN SEA...
DEEP LAYER DRY AIR IN NORTHWESTERLY FLOW ALOFT IS RESULTING IN
GENERALLY FAIR WEATHER ACROSS MUCH OF THE CARIBBEAN. HOWEVER...
UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS CONTINUE TO STREAM
EAST-NORTHEASTWARD ACROSS THE NW CARIBBEAN. A SURFACE RIDGE N OF
THE CARIBBEAN COMBINED WITH BROAD LOW PRES OVER NORTHERN SOUTH
AMERICA WILL CONTINUE TO PRODUCE FRESH TO STRONG TRADE WINDS
ACROSS THE CARIBBEAN. THE STRONGEST OF THESE TRADE WINDS ARE
FOUND NEAR THE COAST OF COLOMBIA...WHERE NE WINDS OF 25 TO 30 KT
ARE OCCURRING. THE TRADE WINDS ARE ADVECTING POCKETS OF LOW
LEVEL MOISTURE AND ISOLATED SHOWERS EASTWARD ACROSS THE
CARIBBEAN...WITH THE GREATEST CONCENTRATION OF THESE SHOWERS
WITHIN 60 NM EITHER SIDE OF A SURFACE TROUGH IN THE NE CARIBBEAN
EXTENDING FROM 17N63W TO E OF PUERTO RICO NEAR 18N65W INTO THE
SW NORTH ATLC.

ATLANTIC OCEAN...
UPPER LEVEL DIVERGENCE AND DEEP LAYER MOISTURE NEAR AN UPPER
LEVEL RIDGE OVER THE SW NORTH ATLC ARE RESULTING IN SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS FROM 21N-30N W OF 76W
INCLUDING CUBA...THE NW BAHAMAS...AND ADJACENT INLAND AREAS OF
FLORIDA. ADDITIONALLY...LOW LEVEL CONVERGENCE IS RESULTING IN
SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF A SURFACE TROUGH
EXTENDING FROM E OF PUERTO RICO NEAR 18N65W TO 21N65W. ALSO...
SCATTERED SHOWERS ARE OCCURRING N OF 24N BETWEEN 58W-67W...WHERE
ATMOSPHERIC INSTABILITY IS PRESENT NEAR AN UPPER LEVEL TROUGH.
ACROSS MUCH OF THE CENTRAL AND E ATLC...A BROAD SURFACE RIDGE
ACROSS IS RESULTING IN GENERALLY FAIR WEATHER. HOWEVER...A
SURFACE TROUGH EXTENDS FROM NE OF THE DISCUSSION AREA TO 32N29W
TO 32N31W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS
WITHIN 60 NM EITHER SIDE OF THIS SURFACE TROUGH. ACROSS THE
TROPICAL ATLC...AN UPPER LEVEL RIDGE IS S OF 14N E OF 53W WITH
AN UPPER LEVEL HIGH NEAR 8N32W. UPPER LEVEL DIVERGENCE NEAR THE
UPPER LEVEL HIGH AND UPPER LEVEL RIDGE IS ENHANCING THE
CONVECTION ASSOCIATED WITH THE ITCZ AND THE TROPICAL WAVE ALONG
42W/43W S OF 16N.

$$
COHEN




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