[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171733
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUN 17 2008

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 35W/36W S OF 12N MOVING W NEAR 15-20
KT. WAVE EXHIBITS AN IMPRESSIVE CLOUD SIGNATURE WITH A WELL
DEFINED LOW-MID LEVEL CYCLONIC CIRCULATION ALONG THE WAVE NEAR
7N. LOW LEVEL SATELLITE DERIVED WINDS AND 850 MB VORTICITY
SUPPORT THE POSITION OF THE WAVE AXIS. SCATTERED MODERATE
CONVECTION IS MAINLY WITHIN 120 NM W OF THE WAVE AXIS FROM
7N-10N.

A TROPICAL WAVE IS ALONG 52W S OF 13N MOVING W NEAR 15-20 KT.
THIS ILL-DEFINED WEAK WAVE SHOWS LOW AMPLITUDE ON THE TOTAL
PRECIPITABLE WATER PRODUCTS WITH VERY LIMITED CONVECTION. THE
SAHARAN AIR LAYER FROM CIMSS INDICATES THAT THE WAVE IS AT THE
LEADING EDGE OF A EXTENSIVE AREA OF AFRICAN DUST.

A TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 87W S OF 21N
MOVING W AT 10-15 KT. THE WAVE IS EMBEDDED IN AN AREA OF DEEP
LAYERED MOISTURE AS DEPICTED ON THE TPW PRODUCT. THIS FEATURE IS
GENERATING ISOLATED SHOWERS AND TSTMS OVER FAR ERN COASTAL
NICARAGUA AND PORTIONS OF CENTRAL CUBA AND ADJACENT COASTAL
WATERS FROM 20N-23N BETWEEN 79W-83W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N24W 7N33W 8N38W 4N52W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 6N-11N
BETWEEN 16W-24W. SCATTERED MODERATE CONVECTION IS FROM 3N-7N
BETWEEN 39W-43W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL TROUGH EXTENDS FROM N FLORIDA TO THE SW PORTION
OF THE GULF WHILE A BROAD UPPER RIDGE REMAINS ANCHORED OVER
NORTH CENTRAL MEXICO COVERING THE NW CORNER OF THE GULF WITH
MODERATE TO STRONG SUBSIDENCE. SW UPPER LEVEL WINDS AHEAD OF THE
TROUGH ARE HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER
WRN CUBA. A WEAK SURFACE TROUGH EXTENDING FROM NE FLORIDA INTO
THE NE GULF NEAR 27N84W IS EXPECTED TO SUPPORT CONVECTION OVER
SOUTH FLORIDA THIS AFTERNOON WHERE HEAVY RAINFALL IS POSSIBLE...
PARTICULARLY ALONG THE EAST COAST METRO AREAS. ACROSS THE
CENTRAL GULF A WEAK RIDGE WITH A 1016 MB HIGH NEAR 26N92W
REMAINS IN CONTROL OF THE WEATHER PATTERN ACROSS THE GULF GIVING
THE AREA MAINLY LIGHT WINDS WITH ONLY WIDELY ISOLATED SHOWERS
AND TSTMS ACROSS THE FAR NRN GULF COAST WHERE AN UPPER DIFFLUENT
PATTERN IS PRESENT. THE RIDGE IS EXPECTED TO PERSIST DURING THE
NEXT SEVERAL DAYS WITH A WEAK COLD FRONT ENTERING THE NE PORTION
OF THE GULF LATE WED. MOSTLY FAIR WEATHER IS NOTED OVER THE
REMAINDER OF THE GULF UNDER THE INFLUENCE OF THE RIDGE.

CARIBBEAN...
A BROAD UPPER RIDGE DOMINATES THE CARIBBEAN ANCHORED ON A HIGH
LOCATED OVER NE NICARAGUA. SWLY WINDS BETWEEN THIS HIGH AND THE
UPPER TROUGH THAT LIES ACROSS THE GULF OF MEXICO ARE
TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE FROM THE EPAC THROUGH
CENTRAL AMERICA INTO THE NW CARIBBEAN...CUBA AND THE BAHAMAS.
UPPER LEVEL DIFFLUENCE AND AFOREMENTIONED TROPICAL WAVE ALONG
87W IS SUPPORTING THE DEVELOPMENT OF SCATTERED MODERATE
CONVECTION ACROSS CUBA EXTENDING SOUTH ACROSS THE CAYMAN ISLANDS
TO NEAR THE HONDURAS/NICARAGUA BORDER. BROAD UPPER RIDGE FROM
THE TROPICAL ATLC COVERS THE E CARIBBEAN WITH STRONG SUBSIDENCE
AND DRY AIR. THE COMBINATION OF A SURFACE HIGH BUILDING N OF THE
AREA IN THE W ATLC AND THE PRESENCE OF THE COLOMBIAN LOW IS
PRODUCING STRONG TRADE WINDS OF 15-25 KT ACROSS THE CENTRAL
CARIBBEAN.

ATLANTIC...
UPPER LEVEL TROUGH EXTENDING FROM N FLORIDA ACROSS THE S CENTRAL
GULF OF MEXICO AND ABUNDANT MID-LEVEL MOISTURE/INSTABILITY IS
INDUCING SCATTERED SHOWERS AND TSTMS ACROSS THE W ATLC MAINLY N
OF 24N AND W OF 65W. THIS INCLUDES MUCH OF THE NRN BAHAMAS.
NEARLY ZONAL UPPER LEVEL FLOW DOMINATES THE W AND CENTRAL ATLC E
OF 65W WITH A PAIR OF SHORT-WAVE TROUGHS ALONG 61W N OF
22N...AND ALONG 51W N OF 27N. A DEEP LAYERED TROUGH LOCATED N OF
AREA SUPPORTS A STATIONARY FRONT THAT ENTERS THE FORECAST AREA
NEAR 32N39W THEN CONTINUES AS A TROUGH TO 24N52W. SCATTERED
SHOWERS ARE WITHIN 120 NM OF THE TROUGH. AN UPPER-LEVEL LOW IS
OVER THE E ATLC NEAR 27N23W. A TROUGH EXTENDS FROM THIS LOW INTO
THE TROPICS NEAR 17N30W. BROAD UPPER E/W RIDGE DOMINATES THE
TROPICS S OF 20N AND WEST OF 25W TO OVER THE E CARIBBEAN. A
BROAD BUT WEAK SURFACE RIDGE COVERS THE ENTIRE FORECAST AREA
WITH A PAIR OF HIGH CENTERS...ONE 1022 MB HIGH IS NEAR
27N57W...AND THE SECOND A 1024 MB HIGH NEAR 30N33W. THE EASTERN
MOST HIGH PRESSURE CENTER WILL REMAIN NEARLY STATIONARY DURING
THE NEXT 24 HOURS. THE PRESSURE GRADIENT BETWEEN THIS HIGH AND
LOWER PRES OVER AFRICA WILL CONTINUE TO PRODUCE MODERATE TO
FRESH NLY WINDS MAINLY N OF 18N AND E OF 25W.

$$
HUFFMAN




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