000
AXPZ20 KNHC 252213
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT AUG 25 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 IS ALONG 82W N OF 3N MOVING W AT 15 KT. SCATTERED
MODERATE CONVECTION PERSISTS DOWNSHEAR OF THE WAVE FROM 8N TO 
10N BETWEEN 85W AND 87W. THIS WAVE IS EMBEDDED IN THE TYPICAL
BROAD SW MONSOONAL FLOW THAT COVERS THE E PACIFIC. A WEAK 
MID-LEVEL CYCLONIC ROTATION IS NOTED ON VISIBLE SATELLITE NEAR 
8N87W.

TROPICAL WAVE IS ALONG 96W N OF 5N MOVING W NEAR 5-10 KT. THIS 
WAVE IS DIFFICULT TO SPOT ON SATELLITE IMAGERY AS IT IS 
INTERTWINED WITH THE ITCZ AND SW TO W ENVIRONMENTAL FLOW THAT 
PREVAILS THROUGHOUT THE THIS PART OF THE PACIFIC. A 1009 MB 
SURFACE LOW IS ANALYZED ON THE WAVE AXIS 14N96W.

...ITCZ...

ITCZ AXIS IS ALONG 9N84W 14N96W 14N110W 13N120W 7N140W. SCATTERED
ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN
96W-102W...WITHIN 120 NM S OF THE AXIS BETWEEN 78W-81W AND 60 NM 
S OF THE AXIS BETWEEN 86W-88W. SCATTERED MODERATE CONVECTION IS
WITHIN 180 NM S OF THE AXIS BETWEEN 102W-116W...AND WITHIN 60 NM
S OF THE AXIS BETWEEN 86W-88W. SCATTERED MODERATE CONVECTION IS
WITHIN 180 NM S OF THE AXIS BETWEEN 102W-116W...AND WITHIN 60 NM
OF THE AXIS BETWEEN 120W-133W.

...DISCUSSION...

E OF 125W...WEAK UPPER LOW HAS MOVED OFF THE MEXICAN COAST IS
NEAR 21N107W MOVING W ABOUT 15 KT. IT IS LOCATED BETWEEN A BROAD 
UPPER ANTICYCLONE OVER NW MEXICO AND A WEAKER UPPER ANTICYCLONE 
OVER SOUTHERN MEXICO. ELY SHEAR DOMINATES THE MID AND UPPER 
LEVELS PRIMARILY S OF 25N TO THE SE OF THE UPPER LEVEL 
ANTICYCLONE OVER NW MEXICO. AMPLE TROPICAL MOISTURE AT ALL 
LEVELS IS EVIDENT S OF 20N. AT THE SURFACE...THE AREA REMAINS 
UNDER BROAD LOW PRES WITH RATHER QUICK S-SW MONSOON FLOW 
THROUGHOUT. SOME OF THE GLOBAL MODEL GUIDANCE SUGGESTS LOW PRES 
GENESIS OFF THE COASTS OF MEXICAN AND COSTA RICA OVER THE NEXT 
FEW DAYS...PERHAPS ATTRIBUTED TO THE WAVES DESCRIBED ABOVE AIDED 
BY PERSISTENT MONSOON FLOW. MODEL MAY BE SOMEWHAT PREMATURE ON 
THIS AS MID AND UPPER LEVEL ELY SHEAR WOULD HAVE TO DECREASE TO 
ALLOW FOR ANY FORMATION OF PERSISTENT LOW PRES TO TRANSPIRE
...ALTHOUGH CANNOT RULE OUT THE POSSIBILITY OF THE CURRENT LOW 
NEAR 14N96W TO CONTINUE INTO THE AT LEAST THE NEXT 36-48 HRS AS 
ITS ASSOCIATED WAVE TRACKS WESTWARD.

W OF 125W...MID AND UPPER LEVELS REMAIN DRY N OF THE ITCZ UNDER
MODERATE SUBSIDENCE ASSOCIATED WITH A BROAD UPPER ANTICYCLONE 
CENTERED NEAR 27N128W. THIS IS SUPPRESSING ANY SIGNIFICANT 
CONVECTIVE DEVELOPMENT EVEN ALONG THE ITCZ. VISIBLE SATELLITE 
IMAGERY SHOWS STRATOCUMULUS CLOUDS MOVING SW NW OF LINE 15N140W 
20N125W AS WELL AS S OF THE ITCZ ASSOCIATED WITH MODERATE TO 
FRESH CROSS EQUATORIAL FLOW. A WEAK SURFACE TROUGH EXTENDS FROM 
21N127W TO LOW PRES NEAR 18N132W 1010 MB AND CONTINUES SW TO 
14N138.5W. DRY AIR AROUND THIS FEATURES IS KEEPING CONVECTION
NON-EXISTENT HERE AS LOW AND TROUGH CONTINUES TO BECOME DIFFUSE.
SURFACE WINDS HERE ARE IN THE LIGHT RANGE WITH RELATIVELY LOW 
SEAS. THE EXCEPTION IS N OF 29N W OF 132W WHERE NE WINDS ARE 
20 KT WITH SEAS TO 8 FT. THESE WINDS AND SEAS ARE FORECAST TO 
LAST THROUGH THE NEXT 24-36 HOURS WITH THE AFFECTED BEING 
RECONFIGURED TO N OF 27N W OF 132W IN 48 HOURS WITH SEAS 
BUILDING TO 8-10 IN PRIMARILY A NE SWELL.

$$
AGUIRRE