000
AXNT20 KNHC 220005
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAY 21 2007

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.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 3N18W 6N33W AND INTO SOUTH 
AMERICA NEAR 4N52W. MODERATE TO STRONG CONVECTION IS LOCATED 
ALONG AND NORTH OF THE ITCZ UP TO THE WEST AFRICAN COAST EAST OF 
14W.  ISOLATED MODERATE CONVECTION ALSO IS OCCURRING NORTH OF 
THE ITCZ BETWEEN 50 AND 55W.  
 
...DISCUSSION...
GULF OF MEXICO...
THE GULF IS DEVOID OF ANY SIGNIFICANT RAIN OR ANY SYNOPTIC 
FEATURES OF INTEREST.  SURFACE HIGH PRESSURE CENTERED EAST OF 
GEORGIA IS PRODUCING A MODEST PRESSURE GRADIENT AND EAST TO 
SOUTHEAST WIND 10 TO 20 KT ARE OCCURRING THROUGHOUT THE GULF.  
IN THE UPPER LEVELS...A WESTERLY JET CORE STRETCHES ACROSS THE 
CENTRAL GULF WITH PEAK WINDS OF ABOUT 90 KT.  NO SIGNIFICANT 
CHANGE TO THE SURFACE CONDITIONS IN THE NEXT DAY ARE 
LIKELY...THOUGH EASTERLIES OF UP TO 25 KT MAY OCCUR IN THE 
EASTERN GULF IN 48 HR AS HIGHER PRESSURES BUILD TO THE NORTH.

CARIBBEAN SEA...
SHIP...BUOY...AND LAND OBSERVATIONS INDICATE THAT THE TROUGH OF 
LOW PRESSURE IN THE WESTERN CARIBBEAN CONTINUES WITH LITTLE 
APPARENT MOVEMENT.  THE TROUGH EXTENDS FROM CENTRAL CUBA AT 
22N80W TO 16N82W TO 10N82W WITH HINTS THAT A LOW MAY BE PRESENT 
AT THE SOUTHERN END OF THE TROUGH.  MODERATE CONVECTION IS SEEN 
WITHIN 120 NMI OF THE TROUGH AXIS SOUTH OF 14N.  THE GFS DOES 
SUGGEST THAT A SURFACE LOW MAY FORM IN THE NEXT DAY OR TWO.  IT 
WOULD NOT BE OUT OF THE QUESTION FOR A TROPICAL CYCLONE TO TRY 
TO FORM.  THERE EXISTS QUITE LARGE AMOUNTS OF LOW-LEVEL 
CONVERGENCE WITH THE NE PACIFIC ITCZ WITH A WELL-DEVELOPED 
MONSOON TROUGH REACHING ACROSS CENTRAL AMERICA ALONG WITH LOW 
TROPOSPHERIC WIND SHEAR SOUTH OF 15N ACCORDING TO THE CIMSS 
ANALYSIS.  HOWEVER...THE CLOSE PROXIMITY TO LAND WOULD LIKELY 
ALLOW FOR SLOW DEVELOPMENT...IF ANY...IN THE NEXT DAY OR TWO.  
REGARDLESS IF THIS DEVELOPS...SUBSTANTIAL RAIN MAY OCCUR IN THE 
SOUTHWESTERN CARIBBEAN AND PARTS OF CENTRAL AMERICA IN THE NEXT 
FEW DAYS. 
 
ATLANTIC OCEAN...
A COLD FRONT EXTENDING FROM A SURFACE LOW WELL NORTH OF THE AREA 
CONNECTS TO A TROUGH NEAR 31N61W. THE TROUGH EXTENDS SW ALONG 
26N65W 24N70W AND JUST NORTH OF HAITI AT 20N72W.  SCATTERED 
SHOWERS ARE OCCURRING WEST OF THE TROUGH AXIS OVER THE CENTRAL 
BAHAMAS...PERHAPS ALSO IN CONNECTION WITH THE TROUGH OVER THE 
WESTERN CARIBBEAN...AND ALSO ALONG THE TROUGH AXIS AND EXTENDING 
180 NMI TO THE EAST OF THE TROUGH AXIS.  SOME OF THE MODEL 
GUIDANCE HAD BEEN ATTEMPTING TO CUT OFF A SURFACE TROUGH NORTH 
OF PUERTO RICO IN THE NEXT 48 HR...THOUGH THE GFS 18Z RUN IS 
LESS BULLISH.  EVEN IF THIS DOES NOT FORM A DISTINCT SURFACE 
LOW...WITH HIGH PRESSURE BUILDING IN THE NEXT TWO DAYS NORTH OF 
THE REGION THE NORTHEASTERLY FLOW EAST OF FLORIDA WILL BE 
STRENGTHENING WITH A LARGE REGION OF WINDS 20-25 KT.

$$
LANDSEA