[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182337
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAR 18 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...
ITCZ AXIS IS CENTERED ALONG 5N9W 2N15W CROSSING THE EQUATOR NEAR
25W EXTENDING TO 1S41W INTO NE BRAZIL NEAR 2S45W. SCATTERED
MODERATE CONVECTION IS FROM 1N-3N BETWEEN 13W-16W...S OF 2N
BETWEEN 22W-28W...AND FROM 2N-5N BETWEEN 42W-46W.

...DISCUSSION...

GULF OF MEXICO...
A SFC TROUGH...WHICH LIKELY BROKE OFF FROM THE TAIL END OF A
STALLED FRONT OVER THE FLORIDA KEYS...IS DRIFTING W ALONG
87W/88W FROM 23N-28N. LOW-LEVEL CONVERGENCE IS TRIGGERING
SCATTERED SHOWERS AND TSTMS...BUT STRONG WLY FLOW ALOFT IS
CONFINING THIS ACTIVITY TO WITHIN 240 NM E OF THE AXIS N OF 25N.
SIMILAR ACTIVITY IS OCCURRING OVER FLORIDA FROM LAKE OKEECHOBEE
SOUTHWARD NEAR THE STALLED FRONT. LOCALLY HEAVY RAINS HAVE BEEN
REPORTED OVER THIS PORTION OF THE STATE TODAY. FAIR WEATHER
PREVAIL ACROSS THE WRN GULF DUE TO ZONAL FLOW AND STABLE AIR
ALOFT. WINDS AND SEAS ARE ALSO RELAXED DUE TO THE CLOSE
PROXIMITY OF A HIGH PRES RIDGE CENTERED OVER THE SE CONUS.

CARIBBEAN SEA...
TRANQUIL WEATHER CONTINUES ACROSS THE MAJORITY OF THE CARIBBEAN
INFLUENCED BY A STRONGLY SUBSIDENT ENVIRONMENT. THIS STABLE
AIRMASS IS BEING ENHANCED BY CONFLUENCE ALOFT NEAR A FLATTENING
UPPER TROUGH THAT EXTENDS ALONG 68W. ONLY EXCEPTION TO THE FAIR
WEATHER IS OVER THE ISLAND OF HISPANIOLA...WHERE SATELLITE
IMAGERY REVEALS DENSE CLOUD COVER WITH EMBEDDED LOW TOPPED
SHOWERS OVER MUCH OF THE ISLAND. THIS ACTIVITY IS LINKED TO A
WEAK TROUGH ALONG 71W. THIS FEATURE MAY BE IN PART LEAD TO THE
DEVELOPMENT OF A MORE SIGNIFICANT LOW OVER THE W ATLC LATER THIS
WEEK OR WEEKEND. TRADE WINDS HAVE SLACKENED SLIGHTLY TODAY...
WITH MAGNITUDES OF 20 KT OR HIGHER CONFINED TO NEAR THE COAST OF
COLOMBIA. THIS FLOW IS EXPECTED TO REMAIN SLIGHTLY LIGHTER THAN
NORMAL OVER THE NEXT COUPLE OF DAYS...ESPECIALLY IF LOW PRES
DOES DEVELOP OVER THE W ATLC.

ATLANTIC OCEAN...
A LARGE LOW PRES SYSTEM PRODUCING STORM FORCE WINDS JUST N OF
THE AREA NEAR 35N56W CONTAINS A COLD FRONT THAT EXTENDS FROM
32N56W TO 27N61W TO 25N70W THEN STATIONARY TO THE FLORIDA KEYS.
SIGNIFICANT MOISTURE IS CONFINED TO THE STATIONARY COMPONENT OF
THE FRONT WHERE LIFT/OVERRUNNING IS PRODUCING SCATTERED SHOWERS
AND TSTMS FROM 24N-29N W OF 76W...INCLUDING THE NW BAHAMAS AND S
FLORIDA. A WEAK SFC TROUGH ALONG 71W S OF 23N IS PRODUCING A FEW
SHOWERS WITHIN 120 NM OF THE AXIS. MORE ON THIS IN THE SECTION
ABOVE. AN ASSOCIATED WARM FRONT EXTENDS E/SE FROM THE LOW
ENTERING THE AREA NEAR 32N46W TO 26N41W THEN BECOMES COLD ALONG
28N31W 32N25W AS IT CONNECTS TO A GALE CENTER NEAR THE AZORES.
ONLY BROKEN CLOUDS AND ISOLATED SHOWERS ARE ALONG THIS FRONT.
FARTHER S...INCLUDING MOST OF THE SUBTROPICS/TROPICS...A WEAK
SFC RIDGE EXTENDING SE FROM A 1018 MB HIGH NEAR 23N42W AND
GENERALLY ZONAL FLOW/SLIGHT RIDGING ALOFT IS PROMOTING MAINLY
FAIR WEATHER AND LIGHT TO MODERATE SFC WINDS.

$$
CANGIALOSI



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