000
AXPZ20 KNHC 050318
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED AUG 05 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 2100 UTC.

...SPECIAL FEATURES...

HURRICANE FELICIA NEAR 12.8N 127.2W WITH A CENTRAL PRESSURE OF 
975 MB AT 0300 UTC AUG 05 MOVING W OR 285 DEG AT 10 KT. 
MAXIMUM SUSTAINED WINDS ARE 85 KT WITH GUSTS TO 105 KT. NUMEROUS 
STRONG CONVECTION IN CLUSTERS IS WITHIN 60 NM OF THE CENTER. A 
WEAK SEEMS TO BE FORMING. UPPER LEVEL DIFFLUENT FLOW IS OBSERVED 
AROUND THE SYSTEM AND STRENGTHENING IS FORECAST AND THE SYSTEM 
IS FORECAST TO FURTHER STRENGTHEN THROUGH LATE WEDNESDAY AND 
CONTINUE TO MOVE WEST TO WEST NORTHWEST. SEE LATEST NHC  
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC 
FOR MORE DETAILS.

TROPICAL STORM ENRIQUE NEAR 15.0N 118.4W WITH A CENTRAL 
PRESSURE OF 998 MB AT 2100 UTC AUG 04 MOVING WNW OR 290 DEG AT 
14 KT. MAXIMUM SUSTAINED WINDS ARE 50 KT WITH GUSTS 60 KT. LARGE 
AREA OF NUMEROUS STRONG CONVECTION IN CLUSTERS IS WITHIN 180 NM 
OF THE POINT 13.5N118W. UPPER LEVEL DIFFLUENT FLOW IS OBSERVED 
AROUND THE SYSTEM AND STRENGTHENING IS FORECAST AND THE SYSTEM 
IS FORECAST TO BECOME A STRONG TROPICAL STORM AND CONTINUE TO 
MOVE WEST NORTHWEST. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE FROM 05N TO 17N ALONG 106W MOVING W 15 KT.  NO 
MAJOR CONVECTION IS NOTED WITH THIS FEATURE. WEAK CYCLONIC 
TURNING NOTED ON VISIBLE IMAGERY. 

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...08N78W TO 
14N114W TO 07N140W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION NOTED WITHIN 15O NM EITHER SIDE OF AXIS BETWEEN 85W 
AND 105W. 

...DISCUSSION...

DEEP LAYER TROUGH EXTENDS FROM 31N130W TO 20N140W. A MID TO 
UPPER LEVEL ANTICYCLONE IS CENTERED OVER CENTRAL MEXICO. 
DIVERGENT FLOW ALOFT BETWEEN THESE FEATURES IS ENHANCING 
CONVECTION OVER FELICIA. 

FURTHER EAST...A WEAK UPPER TROUGH IS ORIENTED NE TO SW ALONG 
17N FROM OVER YUCATAN TO ROUGHLY 13N105W. A SECOND UPPER 
ANTICYCLONE IS NOTED SOUTH OF THIS FEATURE OVER COSTA 
RICA...WITH AN UPPER RIDGE AXIS EXTENDING WEST TO 105W. 
DIVERGENCE ALOFT ASSOCIATED WITH THIS FEATURES IS AIDING 
CONVECTIVE GROWTH ALONG THE ITCZ AS DESCRIBED ABOVE...DESPITE 
ONLY MODEST 10 TO 15 KT CONVERGENCE INTO THE ITCZ IN THE LOWER 
LEVELS. 

GAP WINDS REMAIN ACTIVE THROUGH THE GULFS OF TEHUANTEPEC AND 
PAPAGAYO. THE UPPER TROUGH FROM OVER YUCATAN TO 13N105W IS 
SPONSORING A WEAK SURFACE TROUGH OVER THE EASTERN BAY OF 
CAMPECHE. THE PRESSURE GRADIENT BETWEEN THIS SURFACE TROUGH AND 
HIGH PRES OVER OVER THE NE GULF OF MEXICO IS JUST ENOUGH TO 
MAINTAIN 20 TO 25 KT FLOW THROUGH TEHUANTEPEC. 20 TO 25 KT OVER 
PAPAGAYO ARE THE RESULT OF ENHANCED TRADE WIND FLOW OVER THE 
CARIBBEAN IN ADVANCE OF A TROPICAL WAVE MOVING INTO THE WESTERN 
CARIBBEAN. LITTLE CHANGE IS EXPECTED OVER THE NEXT 48 HOURS. 
HIGHEST WINDS ARE LIKELY IN THE EARLY MORNING WHEN DRAINAGE FLOW 
IS BEST.

$$
CHRISTENSEN