000
AXNT20 KNHC 132352
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 13 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
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...WEATHER OBSERVATIONS...RADAR... 
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 44W S OF 9N MOVING W 10 KT.  WAVE HAS BEEN 
MOVING SLOWLY DUE TO WEAK RIDGING TO THE N.  LOW-LEVEL CYCLONIC 
FEATURE TO THE W DOES NOT APPEAR TO BE DIRECTLY ASSOCIATED WITH 
THE WAVE.  WIDELY SCATTERED MODERATE CONVECTION IS FROM 
4.5N-8.5N BETWEEN 40W-45W.  THE GFS SUGGESTS THAT MOISTURE FROM 
THE WAVE COULD IMPACT THE WINDWARD ISLANDS LATE TUE INTO WED.  

...ITCZ...
ITCZ AXIS ALONG 7N12W 4N20W 2N30W 4N40W 4N51W.  SCATTERED 
MODERATE CONVECTION BETWEEN 8W-14W FROM 2N-7N.  WIDELY SCATTERED 
MODERATE CONVECTION N OF 2N BETWEEN 3W-8W AND S OF 3.5N BETWEEN 
14W-20W.  CLUSTERS OF MODERATE CONVECTION ARE WITHIN 90 NM OF 
3N34W.  

...DISCUSSION...
GULF OF MEXICO...
MUCH DEEPER THAN AVERAGE NEARLY STATIONARY DEEP LAYERED CYCLONIC 
VORTEX SITTING OVER THE GREAT LAKES HAS A LONGWAVE UPPER LEVEL 
TROUGH THAT DIGS SWWD ACROSS THE GULF. UPPER LEVEL CONFLUENT 
FLOW IS GENERATING STRONG SUBSIDENCE ACROSS THE AREA N OF 
24N...SINKING SEWARD. UPPER LEVEL CLOUDINESS IS THINNING S OF 
THE TROUGHW S OF 25N. AT THE SFC...A 1016 MB HIGH IS CENTERED 
150 NM S OF THE AL COAST NEAR 28N87.5W.  CONTINENTAL AIR 
CONTROLS THE REGION WITH MOSTLY CLEAR SKIES UNDER STRONG 
SUBSIDENCE. WINDS ARE FAIRLY LIGHT...GENERALLY FROM THE N E OF 
THE HIGH...TRANSITIONING TO SLY IN THE W GULF.  SMOKE IS VISIBLE 
ON LATE DAY VISIBLE SATELLITE PICTURES S OF 24N WITH PLENTY OF 
MILKY PLUMES SEEN.  WEAK SFC HIGH PRES WILL SHIFT TO THE E OF 
THE AREA LATE TOMORROW AS A COLD FRONT ENTERS THE NW GULF. THE 
LATEST GFS RUN INDICATES THAT THIS FRONT WILL BE FAIRLY STRONG 
AND MAY CLEAR THE ENTIRE AREA BY EARLY WED. A GOOD CHANCE OF 
RAIN IS LIKELY AS THE FRONT APPROACHES WHICH COULD AID 
DROUGHT-PARCHED AREAS OF THE SE USA.    

CARIBBEAN SEA...
BROAD UPPER LEVEL RIDGING COVERS THE AREA GENERATING DRY/STABLE 
AIR ALOFT S OF 17N KEEPING MUCH OF THE REGION SHOWER FREE. THE 
SOUTHEASTERN PERIPHERY OF RIDGE HAS PROMPTED SCATTERED 
SHOWERS/ISOLATED TSTMS INLAND COLOMBIA AND PANAMA.  TYPICAL 
LOW-LEVEL CYCLONIC WINDS IN THE SW CARIBBEAN HAS SHIFTED IN THE 
CENTRAL CARIBBEAN WITH TROUGHING NOTED S OF THE DOMINICAN 
REPUBLIC ALONG 70W AND RATHER RELAXED TRADES IN THE W/CENTRAL 
CARIBBEAN.  UPPER LEVEL MOISTURE IS STREAMING NEWARD ACROSS THE 
NW CARIBBEAN FROM A CONVECTIVE AREA OF LOW PRES IN THE EPAC 
EMBEDDED WITHIN THE ITCZ. SCATTERED SHOWERS/ISOLATED TSTMS ARE 
MAINLY ACROSS THE W COAST OF CENTRAL AMERICA. AT THE SFC...THE 
TAIL END OF A W ATLC COLD FRONT STRETCHES ACROSS W-CENTRAL CUBA 
BUT IS DISSIPATING IN THE CARIBBEAN.  A BROAD SFC RIDGE WILL 
BECOME BETTER ESTABLISHED NE OF THE AREA EARLY NEXT WEEK 
INCREASING THE TRADES ESPECIALLY IN THE E AND CENTRAL 
CARIBBEAN.  
 
ATLANTIC OCEAN...
A LARGE DEEP-LAYERED LOW OVER THE GREAT LAKES IS SUPPORTING A 
SFC COLD FRONT WHICH ENTERS THE AREA ALONG 31N69W 25N75W TO 
W-CENTRAL CUBA. MULTILAYERED CLOUDS AND ISOLATED SHOWERS STRETCH 
WITHIN 180 NM TO THE E OF THE FRONT N OF 25N.  ZONAL FLOW IS E 
OF THE UPPER TROUGH FROM 65W TO 50W WHERE A BROAD DEEP LAYERED 
TROUGH COVERS THE CENTRAL/EAST ATLC N OF 22N FROM 35W-50W.  
TROUGHING DIPS SOUTHWARD INTO THE DEEP TROPICS AONG 22N49W TO 
12N60W.  ASSOCIATED COLD FRONT ENTERS THE AREA ALONG 31N30W 
27N39W THEN AS A DISSIPATING STATIONARY FRONT TO 31N51W. A SFC 
TROUGH IS 150 NM TO THE E OF THE FRONT ALONG 31N27W 21N40W. 
ISOLATED SHOWERS ARE WITHIN 60 NM SE OF THE TROUGH AXIS. AT THE 
SFC...A 1019 MB HIGH IS LOCATED NEAR 25N51W AND IN THE EAST 
ATLC...A 1029 MB HIGH IS CENTERED NEAR 27N23W WITH SFC RIDGING 
STRETCHING SWWARD TO 16N36W. FAIR WEATHER EXISTS UNDER THE 
INFLUENCE OF THE SFC RIDGE WITH NEAR AVERAGE TRADES. IN THE 
TROPICAL ATLC...A BROAD UPPER LEVEL HIGH IS CENTERED NEAR 13N30W 
GENERATING STRONG SUBSIDENCE FROM 6N-15N E OF 34W. A TROPICAL 
JET ORIGINATES ON THE W PERIPHERY OF THE UPPER HIGH AND RACES TO 
THE NE ALONG 12N54W 24N35W 31N23W.  UPPER RIDGING IS MORE 
ENHANCED THAN AVERAGE IN THE TROPICAL E ATLC.. TYPICAL OF THE 
PAST COUPLE OF MONTHS.  

$$
BLAKE