[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 19 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
2315 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N16W 3N30W 1N48W. ISOLATED
MODERATE CONVECTION IS EMBEDDED IN THE ITCZ FROM 24W-30W.
SIMILAR CONVECTION IS WITHIN 180 NM NORTH OF THE AXIS BETWEEN
40W-51W.

...DISCUSSION...

GULF OF MEXICO...
HIGH LEVEL CLOUDS ARE NOTICED FROM SATELLITE IMAGERY DUE TO SW
FLOW ALOFT BRINGING MID LEVEL MOISTURE TO THE REGION.
NEVERTHELESS...THERE IS NO LOW LEVEL SUPPORT TO INITIATE
CONVENTION DUE TO SURFACE HIGH PRESSURE OVER THE NW BASIN
CONTINUES TO BRING A DRIER AIR MASS TO THE ENTIRE BASIN.
CLEARING OF CLOUDS IS BEST SEEN OVER THE NW BASIN WHERE SURFACE
HIGH PRESSURE IS THE STRONGEST. SURFACE NORTHERLY WINDS ARE
NOTED ON SHIP AND BUOY OBSERVATIONS ACROSS THE GULF THIS EVENING
AS SURFACE HIGH PRESSURE IS FORECAST TO BUILD IN ACROSS THE
NORTHERN GULF COAST THROUGH MONDAY.

CARIBBEAN SEA...
A COLD FRONT EXTENDS FROM THE SW NORTH ATLC ACROSS EASTERN CUBA
AND INTO THE NW CARIBBEAN. THIS FRONT IS SUPPORTED ALOFT BY A
VIGOROUS UPPER LEVEL TROUGH LOCATED OFF THE NORTH CAROLINA ATLC
COAST. HOWEVER...THE SOUTHERN TIP OF THIS FRONT IS QUICKLY
WEAKENING AS IT MOVES THROUGH EASTERN CUBA AND CENTRAL JAMAICA.
ISOLATED SHOWERS ARE OCCURRING WITHIN 30 NM E OF THE FRONTAL
BOUNDARY. MIDDLE TO UPPER LEVEL MOISTURE FROM THE EASTERN
PACIFIC IS BEING ADVECTED ACROSS THE NW BASIN...PROVIDING
MOISTURE TO THE FRONTAL BOUNDARY. THE REMAINDER OF THE
CARIBBEAN...EAST OF 73W...IS UNDER THE INFLUENCE OF A BROAD
UPPER LEVEL RIDGE. THEREFORE...MAINLY DRY AIR AND STRONG
SUBSIDENCE IS NOTED IN THE UPPER LEVELS ON WATER VAPOR
IMAGERY...ONLY ISOLATED SHOWERS ARE SEEN ON THE RADAR. EASTERLY
TRADE WINDS UP TO 20 KT CONTINUE AND GENERALLY FAIR SKIES
PREVAIL IN THIS REGION.

ATLANTIC OCEAN...
A 984 MB LOW IS CENTERED AROUND 36N72W WITH A COLD FRONT
EXTENDING SOUTH INTO THE DISCUSSION AREA NEAR 30N64W. THIS COLD
FRONT CONTINUES TO EXTEND SW ALONG 26N68W TO EASTERN CUBA NEAR
21N76W. A SECONDARY WEAKER COLD FRONT IS ANALYZED 100 NM BEHIND
THE MAIN FRONT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
OCCURRING WITHIN 50 NM EAST OF THE MAIN FRONT. FARTHER EAST
ACROSS THE CENTRAL ATLC...ANOTHER COLD FRONT ENTERS THE REGION
NEAR 30N25W AND EXTENDS SW ALONG 25N30W TO 21N38W...WHERE IT
CONTINUES AS A STATIONARY FRONT TO NEAR 23N58W. SCATTERED
SHOWERS AND THUNDERSTORMS ARE OCCURRING WITHIN 150 NM EAST OF
THE FRONT NORTH OF 22N...WHILE ISOLATED SHOWERS LINGER WITHIN
100 NM EITHER SIDE OF THE COLD AND STATIONARY FRONT. THIS
FRONTAL SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH OVER THE
NORTH CENTRAL ATLC. THE EASTERN ATLC IS UNDER THE INFLUENCE OF A
1016 MB HIGH CENTERED NEAR 23N20W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE.

$$

GARCIA


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