000
AXNT20 KNHC 102311
TWDAT 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2230 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 43W/44W S OF 11N MOVING W 10-15 KT. THE 
LAST FRAMES OF VISIBLE SATELLITE IMAGERY FOR THE DAY INDICATE A 
FAIR AMOUNT OF LOW TO MID LEVEL CYCLONIC TURNING. THE MIMIC TPW 
ANIMATION SHOWS GOOD CONTINUITY OF THIS WAVE WITH ITS OVERALL 
MOISTURE FIELD THINNING SLIGHTLY AND BECOMING MORE ABSORBED IN 
THE ITCZ AS IT APPROACHES THE NE COAST OF SOUTH AMERICA. 
SCATTERED SHOWERS SURROUND THE AXIS FROM 3N-7N.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N11W 6N20W 4N30W 2N40W AND INLAND 
OVER NE BRAZIL NEAR THE EQUATOR AND 52W. WIDESPREAD 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N AND 260 
NM S OF THE AXIS BETWEEN 22W-30W. SCATTERED MODERATE CONVECTION 
IS WITHIN 120 NM N OF THE AXIS BETWEEN 33W-40W.

...DISCUSSION...

THE GULF OF MEXICO...
LIGHT TO MODERATE SOUTHERLY WINDS COVER THE ENTIRE GULF DUE TO 
ANTICYCLONIC FLOW AROUND THE WESTERN PERIPHERY OF A BROAD SFC 
HIGH PRES RIDGE CENTERED OVER THE ATLC. PATCHY CLOUDS DOT THE 
GULF...HOWEVER CONVECTION IS LIMITED DUE TO MODERATE SUBSIDENCE 
UNDER AN UPPER LEVEL HIGH OVER THE BAY OF CAMPECHE.  UPPER 
LEVEL MOISTURE FROM PACIFIC IS BEING ADVECTED AROUND THE UPPER 
HIGH AND TRANSPORTED ACROSS THE FAR NORTHERN GULF WATERS. EXPECT 
A COLD FRONT TO ENTER THE NW GULF BY SUNRISE TOMORROW. SOUTHERLY 
WINDS WILL SHIFT NORTH AND INCREASE TO 25 KT BEHIND THE FRONT. 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO 
ENTER THE NW GULF IN ADVANCE OF THE FRONT. 

THE CARIBBEAN SEA...
MODERATE TO STRONG EASTERLY TRADES PERSIST ACROSS THE 
CARIBBEAN. THE STRONGEST WINDS...25-30 KT...ARE ALONG THE COAST 
OF COLOMBIA. SCATTERED LOW-LEVEL CLOUDS AND ISOLATED SHOWERS ARE 
MOVING WEST WITH THESE TRADES...MAINLY N OF 14N. ISOLATED 
SHOWERS AND THUNDERSTORMS HAVE FORMED ALONG THE SOUTHERN COASTS 
OF CUBA AND HISPANIOLA DUE TO DAYTIME HEATING AND OROGRAPHIC 
LIFT. ALOFT...STRONG SUBSIDENCE ON THE EAST SIDE OF AN UPPER 
HIGH OVER THE BAY OF CAMPECHE IS INHIBITING CONVECTIVE ACTIVITY 
IN THE NW CARIBBEAN. AN UPPER TROUGH AXIS EXTENDS OVER THE 
DOMINICAN REPUBLIC AND REACHES AS FAR SOUTH AS PANAMA. UPPER 
LEVEL DIVERGENCE AT THE BASE OF THE TROUGH IS SUPPORTING AN AREA 
OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE SW GULF S OF 12N. 
A PLUME OF UPPER LEVEL MOISTURE IS BEING CARRIED ACROSS THE 
EASTERN CARIBBEAN BY AN UPPER JET ON THE LEADING EDGE OF THE 
TROUGH. 
 
THE ATLANTIC OCEAN...
A LARGE UPPER TROUGH...WITH NUMEROUS EMBEDDED SHORTWAVE 
TROUGHS...LIES OVER THE W ATLC. UPPER LEVEL DIVERGENCE AND 
INSTABILITY NEAR THE SHORTWAVE TROUGHS ARE PRODUCING AREAS OF 
SIGNIFICANT SHOWER AND THUNDERSTORM ACTIVITY. SATELLITE IMAGERY 
AND LIGHTNING DATA INDICATE A LARGE AREA OF SUCH ACTIVITY 
BETWEEN 55W-67W FROM 25N-30N. A SECOND...AND SMALLER...AREA OF 
CONVECTION IS JUST NORTH OF THE DISCUSSION AREA BETWEEN 62W-65W. 
THIS CLUSTER IS RAPIDLY MOVING ENE AROUND A LOW PRESSURE SYSTEM 
TO THE NORTH. FARTHER EAST...A LARGE SFC RIDGE EXTENDS ACROSS 
THE ATLC ANCHORED BY A 1021 MB SFC HIGH PRES NEAR 29N48W. A 
DISSIPATING COLD FRONT CUTS INTO THE RIDGE NEAR 31N31W AND 
EXTENDS TO A WEAK SFC LOW NEAR 27N36W. A DISSIPATING STATIONARY 
BOUNDARY CONTINUES FROM THE LOW CENTER TO 23N50W. A NARROW BAND 
OF LOW CLOUDS AND ISOLATED SHOWERS IS EVIDENT WITHIN 40 NM OF 
THE BOUNDARY N OF 24N. OTHERWISE...FAIR WEATHER CUMULUS CLOUDS 
STREAM AROUND THE HIGH PRES RIDGE. A 1023 MB SFC HIGH REMAINS 
STATIONARY OVER THE AZORES PROVIDING LIGHT WINDS IN THE EAST 
ATLC.

$$
WADDINGTON