000
AXNT20 KNHC 271743
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON APR 27 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
1115 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 04N8W CROSSING THE EQUATOR AT 22W TO 
04S33W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 80 
NM EITHER SIDE OF AXIS FROM 8W-10W AND S OF 1N BETWEEN 35W-37W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYER TROUGHING EXTENDS FROM THE SOUTHERN U.S. PLAINS TO 
THE MEXICAN PLATEAU. STRONG TSTMS ARE NOTED OVER TEXAS AHEAD OF 
FRONT AND DRY LINE COMPLEX...BUT THIS ACTIVITY SHOULD REMAIN N 
OF THE GULF. OTHERWISE A SHARP MID/UPPER LEVEL RIDGE EXTENDS 
FROM THE FLORIDA PANHANDLE TO THE BAY OF CAMPECHE. WITH THE 
EXCEPTION OF THE NW GULF STRONG SUBSIDENCE WITH DRY STABLE AIR 
COVERS THE GULF. GENERALLY SCATTERED CLOUDS PERSIST OVER THE 
AREA...EXCEPT FOR BROKEN LOW CLOUDS NEAR THE TEXAS COAST.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE COVERS THE CARIBBEAN...WITH MOSTLY SW 
TO W UPPER LEVEL WINDS. A BAND OF BROKEN UPPER LEVEL CLOUDS  
EXTENDS FROM HONDURAS TO HISPANIOLA. MODERATE TO STRONG IS OVER 
THE E CARIBBEAN E OF 70W. FRESH TO STRONG SURFACE WIND ACROSS 
MUCH OF THE AREA WITH STRONGEST WINDS IN THE TYPICAL AREA NEAR 
THE COAST OF COLOMBIA. ENOUGH MOISTURE AVAILABLE IN THE LOWER TO 
MID LEVELS OF THE ATMOSPHERE TO SUPPORT BANDS OF SHOWERS ACROSS 
THE CARIBBEAN INDUCED BY THE TRADE WIND CONVERGENCE. AN AREA OF 
MORE CONCENTRATED SHOWERS IS ALONG THE COAST OF PANAMA AND COSTA 
RICE.

ATLANTIC OCEAN...
A LARGE 1032 MB SURFACE HIGH IS JUST  N OF THE AREA NEAR 33N72W. 
THIS HAS TIGHTENED THE PRES GRADIENT WITH 20-25 KT ELY WINDS 
FROM 20N-27N W OF 63W. A WEAKENING COLD FRONT ENTERS THE 
DISCUSSION AREA NEAR 32N48W TO 28N53W. AN UPPER LEVEL TROUGH 
EXTENDS FROM 32N68W TO THE NORTHERN BAHAMAS THEN TO THE STRAITS 
OF FLORIDA. STRONG SUBSIDENCE WITH DRY STABLE AIR IS N OF 25N W 
OF 55W. AN UPPER CYCLONIC CIRCULATION IS NEAR 25N51W. SCATTERED 
SHOWERS ARE WITHIN 60 NM E OF THE CIRCULATION. AN UPPER LEVEL 
RIDGE IS N OF 20N BETWEEN 25W-40W. ACROSS THE FAR EASTERN ATLC 
AN UPPER LEVEL TROUGH WITH AXIS ALONG THE COAST OF AFRICA N OF 
23N. IN THE DEEP TROPICS AND UPPER LEVEL ANTICYCLONIC 
CIRCULATION IS CENTERED NEAR 5N28W.

$$
DGS