Wednesday Afternoon Tropical Weather Discussion

AXNT20 KNHC 181731
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUN 18 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 44W S OF 17N MOVING W 15-20 KT. A BROAD
MID LEVEL CYCLONIC TURNING IS APPARENT JUST AHEAD OF THE WAVE
AXIS NEAR 13N47W WITH SIGNATURE INVERTED-V CLOUD PATTERN EVIDENT
ON VISIBLE SATELLITE IMAGERY. CLUSTERS OF SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION ARE NOTED FROM 7N-12N BETWEEN
40W-44W. THE TPW PRODUCT FROM CIMSS SHOWS A VERY GOOD SURGE OF
MOISTURE ASSOCIATED WITH THIS WAVE.

A TROPICAL WAVE IS ALONG 59W/60W S OF 9N MOVING W 15-20 KT. WAVE
HAS BECOME VERY ILL-DEFINED AND HAS MOVED INLAND ACROSS GUYANA
AND FAR E VENEZUELA WITH ANY ASSOCIATED CONVECTION LIKELY
EMBEDDED WITHIN THE ITCZ ACROSS CENTRAL GUYANA.

A TROPICAL WAVE IS OVER THE YUCATAN PENINSULA AND GUATEMALA WITH
AXIS ALONG 91W S OF 21N MOVING W NEAR 10 KT. NO ORGANIZED
CONVECTION IS ASSOCIATED WITH THE WAVE WITH ONLY SCATTERED
SHOWERS ACROSS SRN MEXICO.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 4N27W 5N35W 8N42W 9N47W
6N56W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION ARE FROM 3N-11N BETWEEN 12W-20W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL TROUGH EXTENDS ACROSS THE GULF REGION WITH ITS
AXIS STRETCHING FROM THE SE CONUS TO THE YUCATAN PENINSULA. A
DIFFLUENT PATTERN BETWEEN THE LEADING EDGE OF THE TROUGH AND AN
UPPER-LEVEL HIGH LOCATED OVER THE CARIBBEAN...JUST SOUTH OF
JAMAICA...IS HELPING TO INDUCE A WIDE AREA OF SHOWERS AND
THUNDERSTORMS ACROSS THE NW CARIBBEAN...WESTERN CUBA...SOUTH
FLORIDA AND THE NW BAHAMAS. ADDITIONAL SHOWERS AND TSTMS ARE
ACROSS THE NRN GULF WATERS ALONG A FRONTAL BOUNDARY THAT
CURRENTLY LIES MAINLY ALONG 28N...EXTENDING FROM THE W ATLC
WATERS ACROSS NRN FLORIDA TO NEAR GALVESTON TEXAS. THE REMAINDER
OF THE GULF IS RATHER TRANQUIL UNDER THE INFLUENCE OF A WEAK
1015 MB SURFACE HIGH ANCHORED IN THE CENTRAL WRN GULF NEAR
25N92W. THE WEAK PRESSURE GRADIENT AROUND THE HIGH IS PRODUCING
MAINLY LIGHT WINDS ACROSS THE BASIN. EXPECT THE COLD FRONT TO
STALL ACROSS THE NE GULF WATERS AND CENTRAL FL TONIGHT LIFTING
NE OF THE AREA THU NIGHT.

CARIBBEAN...
A BROAD UPPER-LEVEL RIDGE AROUND A HIGH NEAR 15N76W DOMINATES
THE WEATHER PATTERN IN THE CARIBBEAN WITH MODERATE TO STRONG
SUBSIDENCE S OF 18N KEEPING THE CENTRAL AND EASTERN CARIBBEAN
MOSTLY CLEAR. DIFFLUENCE ALOFT BETWEEN THIS RIDGE AND THE
AFOREMENTIONED TROUGH OVER THE GULF OF MEXICO IS GENERATING AN
AREA OF SHOWERS AND TSTMS ACROSS THE NW CARIBBEAN AND WRN CUBA
WITHIN 60 NM OF A LINE FROM CIENFUEGOS CUBA TO 17N85W.
REINFORCING HIGH PRESSURE IN THE CENTRAL ATLC IS KEEPING TRADE
WIND FLOW THROUGH THE CARIBBEAN NEAR 20-25 KT.

ATLANTIC...
AS PREVIOUSLY MENTIONED...A BROAD AREA OF SHOWERS AND TSTMS IS
ACROSS WRN CUBA TO THE NW BAHAMAS...INCLUDING PORTIONS OF SRN
FLORIDA AND THE W ATLC W OF 67W. THIS CONVECTIVE ACTIVITY IS
BEING DRIVEN BY UPPER-LEVEL DIFFLUENCE BETWEEN A SHARP TROUGH
OVER THE ERN GULF OF MEXICO AND AN AMPLIFIED RIDGE OVER THE
CARIBBEAN SEA. A COLD FRONT ENTERS THE DISCUSSION AREA NEAR
32N75W AND EXTENDS ACROSS CENTRAL FLORIDA. IT WILL PROVIDE FOCUS
FOR ADDITIONAL SHOWERS AND TSTMS AS IT CONTINUES TO DRIFT SLOWLY
OFF TO THE NE BY THU NIGHT. MOSTLY ZONAL UPPER FLOW DOMINATES
THE WEST AND CENTRAL ATLC WITH A SHORTWAVE MID-UPPER LEVEL
TROUGH NEAR 55W N OF 15N. SCATTERED SHOWERS AND ISOLATED TSTMS
ARE JUST AHEAD OF THE TROUGH AXIS FROM 24N-28N BETWEEN 49W-55W.
A 1024 MB HIGH CENTERED NEAR 29N34W REMAINS IN CONTROL AT THE
SURFACE ACROSS MUCH OF THE ERN AND CENTRAL ATLC. THE PRESSURE
GRADIENT BETWEEN THIS HIGH AND LOWER PRESSURE OVER AFRICA WILL
CONTINUE TO PRODUCE MODERATE NLY WINDS MAINLY N OF 16N AND E OF
25W. AN UPPER LEVEL LOW IS OVER THE E ATLC NEAR 28N23W WITH AN
UPPER LEVEL TROUGH EXTENDING FROM THE LOW TO THE CAPE VERDE
ISLANDS.

$$
HUFFMAN


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