[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT MAR 07 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 1200 UTC SURFACE ANALYSIS...AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N9W 3N12W CROSSING THE EQUATOR
NEAR 20W EXTENDING TO 2S26W AND INTO NE BRAZIL NEAR 3S40W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 2N BETWEEN
19W-25W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 5N
BETWEEN 47W-51W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE DOMINATES MUCH OF THE GULF AND THE SE CONUS
WITH MODERATE TO STRONG SUBSIDENCE IN PLACE OVER THE REGION.
SOUTHEASTERLY SURFACE FLOW OF UP TO 25 KT RESIDES ON THE WRN
PERIPHERY OF A SURFACE RIDGE THAT EXTENDS FROM A 1032 MB HIGH IN
THE W ATLC NEAR 30N71W. EASTERLY WINDS OF 15-20 KT CONTINUE
THROUGH THE STRAITS OF FLORIDA AND ACROSS THE SE PORTION OF THE
GULF S OF 24N. THE SURFACE HIGH IS FORECAST TO REMAIN NEARLY
STATIONARY AND AS A RESULT...THE OVERALL WEATHER PATTERN ACROSS
THE GULF WILL CHANGE LITTLE THROUGH MONDAY.

CARIBBEAN SEA...
FRESH TO STRONG NE-E WINDS ASSOCIATED WITH A 1032 MB SURFACE
HIGH CENTERED IN THE W ATLC NEAR 30N71W ARE TRANSPORTING PATCHES
OF SHALLOW MOISTURE ACROSS CUBA...HISPANIOLA...AND THE NW
CARIBBEAN SEA. THESE WINDS ARE RESULTING IN ADVECTING ISOLATED
SHOWERS ACROSS THE CARIBBEAN WATERS MAINLY N OF 18N. ALSO...A
GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN FROM 10N-13N
BETWEEN 75W-77W OFF THE COLOMBIAN COAST. THE INCREASED SURFACE
WINDS ARE THE RESULT OF A TIGHTENING SURFACE PRESSURE GRADIENT
BETWEEN THE AFOREMENTIONED HIGH OVER THE W ATLC AND LOWER
PRESSURE OVER NRN SOUTH AMERICA. ALOFT...STRONG SUBSIDENCE IS
RESULTING FROM CONFLUENCE IN WESTERLY UPPER LEVEL FLOW AND IS
LIMITING AND DEEP CONVECTION ACROSS THE REGION.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH REMAINS OVER THE CENTRAL ATLC WITH AN
UPPER LOW CENTERED NEAR 25N55W. THIS TROUGH SUPPORTS A COMPLEX
AREA OF LOW PRESSURE WITH A DISSIPATING 1010 MB LOW CENTERED
NEAR 30N51W. A STATIONARY FRONT MEANDERS S-SW TO A PARTIALLY
OCCLUDED 1012 MB LOW NEAR 24N55W. THE ASSOCIATED COLD FRONT
EXTENDS SW ALONG 20N54W TO 15N60W. LOW-LEVEL CONVERGENCE IS
GENERATING SCATTERED SHOWERS WITHIN 90 NM OF THE COLD FRONT. A
PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 26N49W TO 21N50W
WITH SCATTERED SHOWERS WITHIN 120 NM ON EITHER SIDE OF THE
TROUGH. SCATTERED MODERATE CONVECTION IS N OF 23N BETWEEN
44W-56W WITH THIS COMPLEX LOW PRESSURE AREA. ALL OF THIS
ACTIVITY IS BEING SUPPORTED BY UPPER LEVEL DIVERGENCE E OF THE
UPPER TROUGH. ACROSS THE W ATLC...A RELATIVELY COOLER AND DRIER
AIRMASS IS ASSOCIATED WITH A 1032 MB HIGH CENTERED NEAR 30N71W.
BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE NOTED ACROSS THE W ATLC
INTO THE BAHAMAS AND CUBA UNDER A PREVAILING NE FLOW. ACROSS THE
E ATLC...AN UPPER LOW IS LOCATED NEAR 28N22W. ATMOSPHERIC
INSTABILITY ASSOCIATED WITH THIS UPPER LOW IS SUPPORTING
SCATTERED SHOWERS FROM 25N TO BEYOND 32N BETWEEN 11W-23W.
HOWEVER...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS
INHIBITING DEEP CONVECTION ACROSS MUCH OF THE E ATLC. AN
UPPER-LEVEL RIDGE CENTERED NEAR 6N24W DOMINATES MUCH OF THE DEEP
TROPICS AND IS AIDING IN SUPPORTING CONVECTION ALONG THE ITCZ.

$$
HUFFMAN


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