000
AXPZ20 KNHC 132209
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI JUL 13 2007

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 
2145 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 87W N OF 3N HAS MOVED W 15 DURING THE PAST 
24 HOURS. SLIGHT CYCLONIC TURNING IS NOTED OVER LAND NEAR 
14N88W. THERE IS A SLIGHT ENHANCEMENT OF ITCZ CONVECTION ALONG 
THE WAVE AXIS AT 9N89W. 

TROPICAL WAVE IS ALONG 97W N OF 5N MOVING W AT 12 KT BASED ON 
THE PAST 48 HOURS MOTION. THE BROAD CYCLONIC TURNING NOTED 
YESTERDAY HAS DISSIPATED...BUT A CLUSTER OF CONVECTION 
ACCOMPANIES THE WAVE AT 13N97W.

LOW PRES NEAR 14N110.5W 1007 MB ACCOMPANIES THE WAVE ALONG 111W 
N OF 6N AND IS MUCH BETTER ORGANIZED TODAY...WITH TROPICAL 
CYCLONE FORMATION POSSIBLE. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 90 NM NW AND WITHIN 120 NM SE OF THE 
ESTIMATED CENTER...WITH THE HEAVIEST CONCENTRATION OF LIGHTNING 
IN THE NW QUADRANT.  

TROPICAL WAVE IS ALONG 123W WITH LOW PRES ANALYZED NEAR 12N123W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90 
NM 11N124W. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG AXIS 9N85W 7N91W 15N111W 9N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 
NM EITHER SIDE OF LINE 6N78W 12N105W AND WITHIN 150 NM EITHER 
SIDE OF LINE 14N111W 10N135W...AND WITHIN 90 NM OF 13N97W.

...DISCUSSION...

A MID TO UPPER LEVEL TROUGH HAS BEEN REINFORCED BY A SECONDARY 
SHORTWAVE OVER THE W PORTION WITH THE MEAN AXIS SHIFTED W TO 
ALONG 32N138W 18N135W...WITH AN ASSOCIATED SURFACE COLD FRONT 
ALONG 32N137W 28N143W. THE UPPER TROUGH IS EXPECTED TO LIFT NE 
STALLING AND DISSIPATING THE SURFACE FRONT OVER THE NW WATERS 
WITHIN A DAY OR SO. UPPER MOISTURE HAS SPREADING E OVER THE 
AREA OF N OF 24N W OF 128W. 

AN UPPER CYCLONE HAS FORMED NEAR 21N122W AND IS MOVING SLOWLY SW 
AND IS EXPECTED TO WEAKEN AS IT MERGES WITH THE SHORTWAVE TO ITS 
W WITH A NE TO SW UPPER TROUGH LYING ALONG 32N129W 13N137W IN 24 
HOURS. UPPER DEBRIS MOISTURE...ORIGINATING FROM ITCZ CONVECTION 
BETWEEN 100W AND 118W...IS ADVECTED N IN RESPONSE TO THE CYCLONE 
AND WRAPS W OVER THE UPPER LEVELS FROM 23N TO 32N BETWEEN 114W 
AND 123W...BUT SOME OF THE MOISTURE STILLS SPREADS N OVER 
CONUS DESERT SW. 

ELSEWHERE AT THE SURFACE...HIGH PRES IS CENTERED NEAR 29N127W 
1018 MB. 

GAP WINDS...ELY WINDS 20 TO 25 KT IN THE GULF OF PAPAGAYO 
EXPECTED TO RELAX TONIGHT. N WINDS IN THE GULF OF TEHUANTEPEC 
EXPECTED TO AT 15 TO 20 KT TONIGHT WITH AND INCREASE TO 
20...POSSIBLY 25 KT...SAT MORNING THEN DIMINISH THEREAFTER.

$$
NELSON