000
AXNT20 KNHC 151745
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAR 15 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 6N8W 2N15W CROSSING THE EQUATOR 
NEAR 21W EXTENDING TO 2S30W AND INTO NE BRAZIL NEAR 3S40W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 1S-4N 
BETWEEN 4W-15W. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM N 
OF THE AXIS BETWEEN 31W-40W.

...DISCUSSION...

GULF OF MEXICO...
A SLOWLY PROGRESSING COLD FRONT EXTENDS INTO THE N/CENTRAL GULF 
FROM A 1014 MB LOW CENTERED OVER SRN ALABAMA TO NEAR 28N90W. THE 
FRONT CONTINUES AS A STATIONARY FRONT ALONG 28N90W 25N94W TO THE 
MEXICO COAST NEAR 19N95W. IT CONTINUES INLAND ALONG THE ERN 
SLOPE OF THE SIERRA MADRE ORIENTAL MOUNTAINS. THE FRONT IS 
LOCATED AT THE LEADING EDGE OF A WIDE BAND OF CLOUDINESS WITH 
EMBEDDED SHOWERS AND ISOLATED TSTMS N OF THE FRONT AND ALONG THE 
NE GULF COAST BETWEEN MOBILE BAY AND THE WRN FLORIDA PANHANDLE. 
LOW LEVEL CONVERGENCE AND DEEP LAYERED ATMOSPHERIC LIFT ARE 
SUPPORTING THIS CONVECTIVE ACTIVITY. NLY SURFACE WINDS OF UP TO 
20 KT ARE OBSERVED BEHIND THE FRONT. TO THE SE OF THE FRONT... 
MODERATE SUBSIDENCE IS RESULTING IN GENERALLY FAIR WEATHER 
CONDITIONS ACROSS MUCH OF THE S-CENTRAL AND ERN GULF...INCLUDING 
THE FLORIDA PENINSULA. MODERATE SE WINDS ARE BLOWING AHEAD OF 
THE FRONT. ALOFT...A RIDGE WITH AXIS EXTENDING FROM THE YUCATAN 
PENINSULA ACROSS THE FLORIDA PENINSULA INTO THE W ATLC COVERS 
MUCH OF THE GULF WATERS WHILE A CUT-OFF UPPER LOW IS OVER THE 
FOUR CORNERS REGION IN THE SW U.S. SWLY UPPER FLOW BETWEEN THESE 
TWO FEATURES ARE TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE 
ACROSS THE NRN GULF REGION.

CARIBBEAN SEA...
THE COMBINATION OF STRONG HIGH PRESSURE OVER THE W ATLC AND 
LOWER SURFACE PRESSURE OVER NRN SOUTH AMERICA IS PRODUCING FRESH 
TO STRONG WINDS ACROSS MUCH OF THE BASIN. THESE WEATHER 
CONDITIONS ARE EXPECTED TO PERSIST THROUGH EARLY TUESDAY WHEN 
THE PRESSURE GRADIENT GENERATED FROM THE W ATLC HIGH GRADUALLY 
WEAKENS. IN THE MEANTIME...GENERALLY FAIR WEATHER CONDITIONS ARE 
OBSERVED AND EXPECTED TO CONTINUE OVER THE NEXT 24 HOURS ACROSS 
THE CARIBBEAN REGION AS DEEP LAYERED DRY AIR IS PRESENT ON WATER 
VAPOR IMAGERY. HOWEVER...SHALLOW MOISTURE EMBEDDED IN THE TRADE 
WIND FLOW IS MOVING ACROSS THE REGION PRODUCING ISOLATED PASSING 
SHOWERS. THESE PATCHES OF LOW LEVEL MOISTURE ARE MOST IMPACTING 
THE NE CARIBBEAN N OF 15N E OF 77W.

ATLANTIC OCEAN...
A STATIONARY FRONT CLIPS THE FAR NW PORTION OF THE FORECAST AREA 
IN THE FAR W ATLC. MOST OF THE SHOWER ACTIVITY ASSOCIATED WITH 
THIS FRONT REMAINS N OF THE 32N AND OVER THE SE CONUS. A 1027 MB 
SURFACE HIGH IS LOCATED SE OF BERMUDA NEAR 30N60W WITH A RIDGE 
ENVELOPING MUCH OF THE WEST AND CENTRAL ATLC...INCLUDING THE 
BAHAMAS AND GREATER ANTILLES. ALOFT...A RIDGE ALSO DOMINATES 
MUCH OF THE AREA WITH MODERATE TO STRONG SUBSIDENCE AND OVERALL 
FAIR WEATHER CONDITIONS RESULTING AT THE SURFACE. FARTHER TO THE 
E...AN UPPER LEVEL LOW LOCATED NEAR 32N30W SUPPORTS A 1008 MB 
SURFACE LOW LOCATED NEAR 31N31W. A SURFACE TROUGH EXTENDS FROM 
THE LOW ALONG 30N30W 26N29W 22N30W 18N37W. UPPER LEVEL 
DIFFLUENCE AND LOW LEVEL CONVERGENCE IN THE VICINITY OF THE 
SURFACE LOW AND TROUGH ARE GENERATING AN AREA OF SCATTERED 
SHOWERS N OF 26N BETWEEN 24W-31W. THE REMAINDER OF THE E ATLC IS 
UNDER THE INFLUENCE OF A NARROW SURFACE RIDGE ANCHORED ON A 1017 
MB HIGH NEAR 18N28W AND PRODUCING MOSTLY FAIR WEATHER. ACROSS 
THE DEEP TROPICS...A BROAD UPPER LEVEL RIDGE WITH AXIS ORIENTED 
E-W ALONG 6N BETWEEN 13W-60W IS ENHANCING CONVECTION ASSOCIATED 
WITH THE ITCZ.

$$
HUFFMAN