000
AXNT20 KNHC 180513
TWDAT 

TROPICAL WEATHER DISCUSSION...     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI APR 18 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N9W 4N19W 4N28W 1N38W CROSSING THE 
EQUATOR NEAR 47W TO 1S50W. SCATTERED/NUMEROUS STRONG CONVECTION 
IS FROM 1N TO JUST INLAND OVER IVORY COAST AFRICA BETWEEN 3W-7W. 
CLUSTERS SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 
4N TO S OF THE EQUATOR W OF 26W TO INLAND OVER SOUTH AMERICA.    

...DISCUSSION...

GULF OF MEXICO...
UPPER RIDGE ANCHORED IN THE E PACIFIC REGION COVERS THE GULF 
WITH THE AXIS EXTENDING FROM THE E BAY OF CAMPECHE TO OVER THE 
SE US AND ALONG THE APPALACHIAN MOUNTAINS PROVIDING MODERATE 
SUBSIDENCE AND RATHER DRY AIR OVER THE GULF. A SURFACE RIDGE 
COVERS THE GULF ANCHORED BY A 1023 MB HIGH OFF THE COAST IN THE 
W ATLC NEAR JACKSONVILLE. RETURN SOUTHERLY FLOW AROUND THE 
SURFACE RIDGE IS BANKING LOW LEVEL ALONG THE COAST OF NE MEXICO 
AND TEXAS AHEAD OF A COLD FRONT THAT IS ACROSS CENTRAL TEXAS. 
THIS FRONT AND THE ASSOCIATED DEEP LAYERED TROUGH WILL MOVE 
INTO THE GULF DURING THE DAY FRI DISSIPATING OVER THE E GULF SAT 
INTO SUN. OTHERWISE THE GULF REMAINS RELATIVELY CLEAR TONIGHT. 
 
CARIBBEAN SEA...
THE DEEP LAYERED TROUGH FROM THE W ATLC DIPS OVER THE N 
CARIBBEAN TO JAMAICA BETWEEN HISPANIOLA AND W CUBA TO JUST E OF 
THE CAYMAN ISLANDS. THE ASSOCIATED STATIONARY FRONT EXTENDS FROM 
THE W ATLC TO OVER HISPANIOLA. UPPER WESTERLY FLOW DOMINATES THE 
REMAINDER OF THE CARIBBEAN. STRONG NE TO E TRADE WINDS ARE 
ACROSS THE CARIBBEAN WITH THE HIGHEST WINDS ALONG THE COAST OF 
COLOMBIA. THESE TRADE WINDS COUPLED WITH THE REMNANTS OF THE 
FRONTAL BOUNDARY ARE BANKING LOW CLOUDS WITH ISOLATED SHOWERS NW 
OF A LINE FROM HISPANIOLA W ACROSS JAMAICA TO 17N80W TO NE 
HONDURAS. CONVERGENCE OF THE UPPER LEVEL WINDS AND SURFACE FLOW 
OVER THE SW CARIBBEAN IS GENERATING SCATTERED SHOWERS/ 
THUNDERSTORMS WITHIN 75 NM ALONG THE COAST OF PANAMA AND COST 
RICA S OF 11N W OF 80W. OTHERWISE THE CARIBBEAN REMAINS 
RELATIVELY CLEAR TONIGHT. 

ATLANTIC OCEAN...
BROAD DEEP LAYERED TROUGH COVERS THE W ATLC FROM 60W TO THE E 
COAST OF FLORIDA WITH THE MAIN UPPER LOW WELL N OF THE REGION. 
AT THE SURFACE...A COLD FRONT ENTERS THE REGION E OF  BERMUDA 
NEAR 32N60W TO 28N62W CONTINUING S AS A STATIONARY FRONT TO OVER 
HISPANIOLA NEAR 18N71W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
ARE WITHIN 60/75 NM OF THE FRONT N OF 20N WITH SCATTERED SHOWERS 
S OF 20N TO OVER HISPANIOLA BETWEEN THE MONA PASSAGE AND THE 
WINDWARD PASSAGE. A WEAK SURFACE TROUGH EXTENDS FROM 31N68W SW 
TO 26N75W. BROAD DEEP LAYERED RIDGE COVERS THE REMAINDER OF THE 
ATLC WITH THE UPPER RIDGE ANCHORED BY AN UPPER HIGH NEAR 26N36W 
AND THE SURFACE 1031 MB HIGH ANCHORED NEAR 32N44W. THE TYPICAL 
E/W UPPER RIDGE ACROSS THE TROPICS REMAINS SUPPRESSED TO THE S 
BY THIS STRONG UPPER RIDGE AND GENERATING A SHEAR AXIS EXTENDING 
FROM W AFRICA NEAR 21N16W ALONG 16N30W TO 15N42W. THUS GIVING 
THE ATLC E OF 60W FAIR WEATHER TONIGHT. 

$$
WALLACE