000
AXPZ20 KNHC 300936
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU AUG 30 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 
0915 UTC.

...SPECIAL FEATURES...

AT 30/0600 UTC...TROPICAL STORM GIL CENTERED NEAR 19.4N 
112.4W...OR ROUGHLY 250 NM SSW OF THE SOUTHERN TIP OF BAJA 
CALIFORNIA...MOVING W AT 12 KT. MAXIMUM SUSTAINED WIND SPEED IS 
35 KT WITH GUSTS TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 
999 MB. A CLUSTER OF MODERATE TO STRONG CONVECTION IS FLARING 
NEAR THE LOW LEVEL CENTER OF GIL...MAINLY WITHIN 120 NM OF THE 
SW QUADRANT. THE STORM IS EXPERIENCING MODERATE TO STRONG NELY 
SHEAR CURRENTLY...AND THE SURFACE CENTER IS ESTIMATED TO LIE 
SLIGHTLY UPSHEAR ON THE NE PORTION OF THE CONVECTIVE CLUSTER. 
WHILE THE STORM MAY INTENSIFY SLIGHTLY THIS MORNING AS THE 
CONVECTION CONTINUES...THE SHEAR WILL LIKELY BEGIN TO WEAKEN GIL 
LATER TODAY. IN ADDITION...GIL WILL ENTER COOLER WATERS OVER THE 
NEXT 2 TO 3 DAYS...WEAKENING THE SYSTEM FURTHER. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC 
FOR MORE DETAILS.

A 1008 MB LOW CENTERED NEAR 12N97W...OR ABOUT 330 NM SSE OF 
ACAPULCO MEXICO...MOVING W AT 5 TO 10 KT. A CLUSTER OF STRONG 
CONVECTION IS DEVELOPING N OF THE CENTER JUST OFF THE COAST TO 
THE SE OF ACAPULCO...N OF 13N BETWEEN 96W AND 99W. THIS IS 
LIKELY DUE TO LOW LEVEL CONVERGENCE BETWEEN SELY FLOW ON THE E 
SIDE OF THE LOW AND DRAINAGE FLOW ALONG THE MEXICAN COAST. A 
WEAKENING BAND OF CONVECTION IS EVIDENT S OF THE LOW WITHIN 30 
NM OF A LINE FROM 9N101W TO 10N96W. THE LOW IS CURRENTLY IN AN 
AREA OF LIGHT ELY SHEAR BUT IS SLOWLY MOVING TOWARD AND AREA OF 
SLIGHTLY STRONGER SHEAR. IF THIS TREND CONTINUES...THE LOW MAY 
INTENSIFY INTO A TROPICAL CYCLONE OVER THE NEXT 48 HOURS. 

...TROPICAL WAVE...

A TROPICAL WAVE ALONG 93W N OF 9N IS MOVING W 10 TO 15 KT TOWARD 
THE GULF OF TEHUANTEPEC. WHILE THE NORTHERN HALF OF THE WAVE IS 
FAIRLY WELL DEFINED OVER THE BAY OF CAMPECHE...THE SOUTHERN HALF 
OF THE WAVE IS STARTING TO INTERACT WITH THE LOW S OF ACAPULCO 
AND IS LOSING ITS DEFINITION AS A DISTINCT ENTITY. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N86W 16N103W 10N125W 15N140W. 
ASIDE FROM THE CONVECTION NOTED ABOVE...NO SIGNIFICANT 
CONVECTION IS NOTED ALONG THE ITCZ AXIS.

...DISCUSSION...

E OF 120W...LIGHT TO MODERATE WINDS CONTINUE TO FLOW N ACROSS 
THE EQUATOR TO AROUND 11N OVER THE FAR ERN PACIFIC. THESE WINDS 
HAVE WEAKENED OVER THE LAST COUPLE OF DAYS HOWEVER...LIMITING 
THE LOW LEVEL CONVERGENCE WITH ELY FLOW TO THE NORTH. ALOFT...E 
TO NE SHEAR PERSISTS...WHICH IS ALSO NOT PARTICULAR CONDUCIVE TO 
CONVECTIVE DEVELOPMENT. AS A RESULT...CONVECTION IS FAIRLY 
LIMITED SAVE FOR AREAS ALONG THE MEXICAN AND CENTRAL AMERICAN 
COASTS...AND IN THE VICINITY OF T.S. GIL AND THE LOW S OF 
ACAPULCO. AS WITH THE PAST COUPLE OF NIGHTS...THE MOST PROMINENT 
CONVECTIVE CLUSTERS ARE ALONG THE COAST OF MEXICAN STATE OF 
SINALOA. WHILE T.S GIL IS EXPECTED TO WEAKEN OVER COOLER WATERS 
IN THE NEXT 48 HOURS...THE OTHER LOW MAY INTENSIFY AS IT MOVES 
W...DEPENDING LARGELY ON THE IMPACT OF THE ELY SHEAR. WINDS S OF 
THIS LOW WILL LIKELY INCREASE AS THE LOW DEEPENS. IN 
ADDITION...LONG PERIOD SWELL OF UP TO 7 FT OUT OF THE S PACIFIC 
WILL ARRIVE ALONG PORTIONS OF THE MEXICAN AND CENTRAL AMERICAN 
COASTS BY FRIDAY.

W OF 120W...DEEP LAYER MOISTURE REMAINS LACKING OVER ENTIRE 
REGION...WITH CONVECTION PRACTICALLY NON EXISTENT EVEN OVER 
THE ITCZ. ONLY LIGHT TO MODERATE WINDS ARE EVIDENT ON SHIP 
OBSERVATIONS AND SCATTEROMETER DATA. SOME SWELL UP TO 8 FT 
CONTINUES TO PUSH INTO THE AREA FROM THE S PACIFIC MAINLY S OF 
THE ITCZ.

$$
CHRISTENSEN