[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 150549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU MAY 15 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 19W S OF 12N MOVING W AT 10-15 KT.
A LARGE AREA OF SHOWERS AND EMBEDDED TSTMS ARE ASSOCIATED WITH
THE WAVE...BUT MOST OF THIS ACTIVITY IS W OF THE WAVE AXIS. IN
ADDITION...THE MIMIC-TPW PRODUCT FROM CIMSS SHOWS THE PRESENCE
OF THIS SYSTEM WITH AN AREA OF MOISTURE EXTENDING NWD TO NEAR
12N.

A WEAK TROPICAL WAVE IS ALONG 63W/64W S OF 12N MOVING W AT 10
KT. THE WAVE IS VERY ILL-DEFINED AND MOSTLY INLAND OVER E
VENEZUELA WHERE IT IS GENERATING SCATTERED MODERATE CONVECTION.
THE GFS MODEL GUIDANCE INDICATES LOW-LEVEL MOISTURE WILL REMAIN
ACROSS N VENEZUELA AND ADJACENT COASTAL WATERS IN THE CARIBBEAN
SEA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N2W 4N9W 5N16W 3N22W 1N32W 7N51W
8N59W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM EQ-4N
BETWEEN THE PRIME MERIDIAN TO 3W.  SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS FROM 1N-4N BETWEEN 8W-15W.
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE
WITHIN 120-150 NM FROM A LINE 7N22W TO 4S28W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF OF MEXICO LIES BETWEEN A 1021 MB SURFACE HIGH OFFSHORE
OF THE CAROLINAS IN THE W ATLC AND LOW PRESSURE TROUGHING OVER
E TEXAS AND E MEXICO. THIS WEATHER PATTERN IS PRODUCING FAIRLY
UNIFORM 15-20 KT SOUTHERLY WINDS ACROSS THE GULF. SCATTERED
SHOWERS AND THUNDERSTORMS REMAIN ALONG THE EASTERN COASTS
OF N MEXICO AND EXTREME S TEXAS THIS EVENING. THIS ACTIVITY WILL
CONTINUE TO DISSIPATE ACROSS THE FAR W GULF OVERNIGHT. ALOFT...A
LARGE UPPER HIGH CENTERED OVER THE YUCATAN PENINSULA EXTENDS A
RIDGE ACROSS THE ENTIRE GULF WITH ITS ASSOCIATED FLOW
TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE FROM THE EPAC THROUGH
MEXICO INTO SE TEXAS AND MUCH OF THE GULF. GIVEN DIFFLUENT UPPER
LEVEL PATTERN ACROSS THE NW GULF INCREASED PRECIPITATION CHANCES
ARE EXPECTED AHEAD OF THE NEXT COLD FRONT WHICH IS FORECAST TO
ENTER THE GULF ON THURSDAY AFTERNOON.

CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT EXTENDING FROM THE CENTRAL ATLC IS
PRODUCING SOME SCATTERED SHOWER ACTIVITY N OF JAMAICA...ACROSS
HISPANIOLA AND THE WINDWARD PASSAGE. OTHERWISE...VERY TRANQUIL
WEATHER RESIDES ACROSS THE CARIBBEAN BASIN IN LARGE PART DUE TO
A LARGE MID-UPPER RIDGE CENTERED OVER THE YUCATAN PENINSULA AND
UPPER TROUGHING OVER THE E CARIBBEAN. THESE UPPER FEATURES ARE
PRODUCING MODERATE TO STRONG SUBSIDENCE ACROSS THE CARIBBEAN SEA
SUPPRESSING THE DEVELOPMENT OF ANY SIGNIFICANT CONVECTION. THE
GFS MODEL GUIDANCE KEEPS MOISTURE FROM THE TAIL END OF THE FRONT
AFFECTING HISPANIOLA THROUGH FRI.

ATLANTIC OCEAN...
A LARGE 999 MB LOW PRESSURE SYSTEM IS WELL N OF THE AREA OVER
THE W ATLC. THE ASSOCIATED COLD FRONT ENTERS THE FORECAST AREA
NEAR 32N54W THEN CONTINUES SW CROSSING JUST N OF HISPANIOLA INTO
THE WINDWARD PASSAGE AND S OF CUBA. LOW-LEVEL CONVERGENCE
ALONG THE FRONTAL BOUNDARY COUPLED WITH UPPER DIFFLUENT FLOW IS
PRODUCING A 120-150 NM WIDE BAND OF SCATTERED SHOWERS AND
THUNDERSTORMS IMMEDIATELY E OF THE FRONT. COLD AIR STRATOCUMULUS
CLOUDS ARE BEHIND THE FRONT ACROSS THE W ATLC AND IMPLY THAT A
COOL AND DRIER AIR MASS HAS TAKEN HOLD ACROSS THE BAHAMAS. THE
REST OF THE CENTRAL AND E ATLC IS DOMINATED BY A 1026 MB SURFACE
HIGH LOCATED NEAR 30N39W. IN THE UPPER LEVELS...RIDGING SUPPORTS
CENTRAL ATLC SURFACE HIGH WITH AXIS EXTENDING ALONG 40W. BROAD
TROUGHING WITH BASE S OF THE CANARY ISLANDS WILL CONTINUE TO
MOVE EASTWARD AND PROVIDE ONLY MID-UPPER LEVEL CLOUDINESS ALONG
AND NW OF COASTAL MOROCCO.

OF NOTE...TODAY MARKS THE BEGINNING OF THE EASTERN PACIFIC
HURRICANE SEASON. BASED ON LATEST AVERAGES...EVERY YEAR 15 NAMED
STORMS FORM...9 OF WHICH BECOME HURRICANES AND 4 OF THOSE
HURRICANES WOULD BE OF CATEGORY 3 OR GREATER IN STRENGTH ON THE
SAFFIR-SIMPSON SCALE. THE ATLANTIC HURRICANE SEASON BEGINS JUNE
1ST WITH BOTH ATLANTIC AND EASTERN PACIFIC TROPICAL SEASONS
ENDING NOVEMBER 30TH.

$$
HUFFMAN




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