[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 162328
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 16 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 2245 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 84W S OF 18N MOVING W AROUND 15 KT. THIS
WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE
TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. VISIBLE SATELLITE
IMAGERY DEPICTS CYCLONIC CIRCULATION IN THE MOTION OF LOW LEVEL
CLOUDS NEAR THIS WAVE. THIS WAVE IS SUPPORTING SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 10N-18N BETWEEN 82W-86W
INCLUDING PORTIONS OF HONDURAS...NICARAGUA...AND COSTA RICA. THIS
CONVECTION IS ALSO BEING SUPPORTED BY UPPER LEVEL DIVERGENCE
ASSOCIATED WITH AN UPPER LEVEL HIGH CENTERED OVER THE W CARIBBEAN
NEAR 18N87W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N13W 7N23W 6N33W 2N43W TO THE
EQUATOR ALONG 52W. SCATTERED MODERATE CONVECTION IS FROM 5N-7N
BETWEEN 9W-11W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 4N-8N BETWEEN 14W-22W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS ALSO FROM 3N-8N BETWEEN 25W-35W. SCATTERED MODERATE
CONVECTION IS S OF 6N BETWEEN 37W-52W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH EXTENDS FROM THE S FLORIDA PENINSULA NEAR 25N81W TO
24N84W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THIS TROUGH
INCLUDING PORTIONS OF THE S FLORIDA PENINSULA AND THE FLORIDA KEYS.
A SECOND SURFACE TROUGH IS AFFECTING PORTIONS OF THE S GULF. THIS
SECOND SURFACE TROUGH EXTENDS FROM N OF THE YUCATAN PENINSULA NEAR
22N90W TO S GUATEMALA NEAR 15N90W. LOW LEVEL CONVERGENCE NEAR THIS
TROUGH IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS FROM
16N-22N BETWEEN 87W-92W INCLUDING PORTIONS OF THE YUCATAN
PENINSULA...BELIZE...AND GUATEMALA. THIS ACTIVITY IS BEING ENHANCED
BY UPPER LEVEL DIVERGENCE AROUND AN UPPER LEVEL HIGH CENTERED OVER
THE W CARIBBEAN NEAR 18N87W. THE SECOND SURFACE TROUGH IS FORECAST
TO MOVE WESTWARD ACROSS THE BAY OF CAMPECHE TONIGHT THROUGH
THURSDAY. ACROSS THE N AND CENTRAL GULF...DEEP LAYER DRY AIR IS
PRESENT...WITH A 1017 MB SURFACE HIGH OVER THE N GULF NEAR 28N87W.
ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS AFFECTING MUCH OF THE
GULF...WITH SE TO S WINDS OF 15 TO 20 KT OCCURRING ACROSS PORTIONS
OF THE NW GULF IN RESPONSE TO A BROAD SURFACE TROUGH OVER MEXICO AND
THE SOUTHERN PLAINS OF THE UNITED STATES.

CARIBBEAN SEA...
A SURFACE TROUGH EXTENDS FROM N OF THE YUCATAN PENINSULA NEAR 22N90W
TO S GUATEMALA NEAR 15N90W. DEEP LAYER MOISTURE ACROSS THE W
CARIBBEAN AND LOW LEVEL CONVERGENCE NEAR THE TROUGH ARE SUPPORTING
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE NW CARIBBEAN FROM
16N-22N W OF 87W INCLUDING PORTIONS OF THE YUCATAN PENINSULA...
BELIZE...AND GUATEMALA. THESE SHOWERS AND THUNDERSTORMS ARE BEING
ENHANCED BY UPPER LEVEL DIVERGENCE IN THE VICINITY OF AN UPPER LEVEL
HIGH CENTERED OVER THE W CARIBBEAN NEAR 18N87W. THIS UPPER LEVEL
DIVERGENCE IS ALSO COMBINING WITH ATMOSPHERIC INSTABILITY TO RESULT
IN SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CUBA AND THE NEARBY
COASTAL WATERS. FARTHER TO THE E...GENERALLY FAIR WEATHER IS
OCCURRING ACROSS MUCH OF THE E CARIBBEAN...WHERE DEEP LAYER MOISTURE
IS SOMEWHAT MORE LIMITED. HOWEVER...ATMOSPHERIC INSTABILITY NEAR AN
UPPER LEVEL TROUGH OVER THE NE CARIBBEAN IS SUPPORTING SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS HISPANIOLA...PUERTO RICO...AND THE
NEARBY COASTAL WATERS.

ATLANTIC OCEAN...
ACROSS THE SW NORTH ATLC...A SURFACE TROUGH EXTENDS FROM 31N81W TO
THE E FLORIDA PENINSULA NEAR 28N80W. LOW LEVEL CONVERGENCE NEAR THIS
TROUGH IS INTERACTING WITH MOISTURE IN NORTHWESTERLY FLOW ALOFT TO
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS N OF 23N W OF 77W
INCLUDING PORTIONS OF THE NW BAHAMAS AND THE E FLORIDA PENINSULA.
ALSO...UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS N OF 27N BETWEEN 67W-76W. ACROSS MUCH OF THE
CENTRAL AND E ATLC...GENERALLY FAIR WEATHER IS PRESENT WHERE
SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. HOWEVER...AN
UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLC N OF 26N BETWEEN
40W-52W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS TROUGH IS
SUPPORTING SCATTERED SHOWERS N OF 28N BETWEEN 42W-50W. ALSO...A DEEP
LAYER LOW OVER THE E ATLC IS ASSOCIATED WITH A 1012 MB SURFACE LOW N
OF THE CANARY ISLANDS NEAR 32N16W. THIS SURFACE LOW IS ASSOCIATED
WITH GALE FORCE WINDS. LOW LEVEL CONVERGENCE NEAR THE SURFACE LOW IS
SUPPORTING SCATTERED SHOWERS N OF 30N BETWEEN 14W-19W. THE SURFACE
LOW IS FORECAST TO MOVE SOUTHWESTWARD DURING THE NEXT DAY AND BE
LOCATED NEAR 29N17W AS A 1011 MB SURFACE LOW AT 17/1800 UTC. ACROSS
THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS PRESENT WITH AN
AXIS EXTENDING FROM 12N16W TO AN UPPER LEVEL HIGH NEAR 10N38W TO
7N59W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THESE FEATURES IS
SUPPORTING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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