000
AXPZ20 KNHC 270923
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JUL 27 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...SPECIAL FEATURE...
DALILA HAS BEEN DOWNGRADED TO A TROPICAL DEPRESSION. AT 27/09Z 
DALILA WAS CENTERED NEAR 22.9N 117.2W MOVING WNW AT 10 KT. 
MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC 
FOR MORE DETAILS. DALILA APPEARS TO BE FINALLY SUCCUMBING TO THE 
UNFAVORABLE OCEANIC CONDITIONS. NEARLY ALL OF THE DEEP 
CONVECTION HAS FIZZLED AND THE LOW AND MID-LEVEL CIRCULATION 
APPEAR DECOUPLED. DEGENERATION IS EXPECTED TO CONTINUE AND 
DALILA WILL LIKELY BE A REMNANT SWIRL LATER TODAY. 

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 103W/104W N OF 4N MOVING W 10-15 KT. THE 
OVERALL STRUCTURE OF THIS WAVE HAS CHANGED LITTLE OVER THE PAST 
24 HOURS. SATELLITE IMAGERY CONTINUES TO INDICATE A WEAK BROAD 
E-W CYCLONIC GYRE WITH EMBEDDED POCKETS OF SCATTERED SHOWERS AND 
ISOLATED TSTMS MAINLY WITHIN 240 NM W OF THE WAVE AXIS. AN 
EARLIER QSCAT PASS SHOWED AN AREA OF SLY WINDS TO 20 KT NEAR THE 
BASE OF THE WAVE. SOME OF THE COMPUTER MODELS THAT INITIALIZE 
THIS WAVE REALISTICALLY ...UKMET...CMC AND ECMWF...SUGGEST SOME 
IMPROVED ORGANIZATION OVER THE NEXT COUPLE OF DAYS.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N78W 12N100W 6N107W 18N111W 11N130W 
12N140W. SCATTERED MODERATE FROM 3N-5N E OF 80W AND FROM 13N-16N 
BETWEEN 89W-95W. 

...DISCUSSION...

W OF 120W...
STRONG CONFLUENT FLOW ALOFT...BETWEEN AN UPPER LOW N OF THE 
HAWAIIAN ISLANDS AND INVERTED TROUGHING ALONG 123W...IS 
PROVIDING WIDESPREAD DRY AIR IN THE MID AND UPPER LEVELS ACROSS 
THIS PART OF THE EPAC. SOME UPPER MOISTURE IS TRYING TO PUSH 
INTO THE SW CORNER OF THE DISCUSSION AREA BUT IS QUICKLY DRYING 
OUT IN THIS VERY STABLE AIRMASS. THE CONDITIONS HERE ARE SO 
TRANQUIL THAT THE ITCZ IS ABSENT OF ANY CONVECTION ATTM. IN THE 
LOWER LEVELS...SCATTERED STRATOCUMULUS DECK IS BEING PUSHED 
TOWARD THE SW BY MODERATE TO FRESH NELY TRADES. A QSCAT PASS 
AROUND 03Z SHOWED THAT STRONGEST WINDS WERE IN THE 15-20 KT 
RANGE. THESE WINDS WILL LIKELY SLACKEN TO 10-15 KT AS DELILA 
WEAKENS. 

E OF 120W...
A FAIR AMOUNT OF UPPER MOISTURE IS IN PLACE ACROSS THIS PART OF 
THE DISCUSSION AREA...DRIVEN BY ELY FLOW ON THE SRN PERIPHERY OF 
AN UPPER HIGH OVER THE BAY OF CAMPECHE. HOWEVER...WATER VAPOR 
IMAGERY INDICATES A PRONOUNCED DRY WEDGE MAKING ITS WAY FROM THE 
CARIBBEAN SEA TO HONDURAS AND NICARAGUA. THIS DRY SLOT SHOULD 
MOVE OVER THE EPAC WATERS DURING THE NEXT FEW HOURS. THESE 
OVERALL MOIST CONDITIONS ARE ALLOWING CONVECTION TO FORM NEAR 
THE TROPICAL WAVE AND FURTHER E IN THE GULF OF TEHUANTEPEC. 
BESIDES FOR THOSE AREAS...CONVECTION IS MINIMAL...EVEN NEAR THE 
TROPICAL DEPRESSION. 

$$
CANGIALOSI