000
AXPZ20 KNHC 180249
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU SEP 18 2008

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0115 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 86W N OF 09N...PASSING THROUGH 
HONDURAS...NICARAGUA...AND NE COSTA RICA...MOVING W 15 KT. 
NUMEROUS MODERATE TO STRONG CONVECTION W OF TROPICAL WAVE TO 88W 
WITHIN 60 NM OF THE COAST.

TROPICAL WAVE ALONG 96W N OF 06N TO THE SW MEXICAN COAST MOVING 
W 15 KT. ORGANIZED CONVECTION MAINLY S OF 10N ASSOCIATED WITH 
THE ITCZ.

TROPICAL WAVE ALONG 118W FROM 06N TO 16N MOVING WEST 15 KT. 
MINIMAL CONVECTION ASSOCIATED WITH THIS TROPICAL WAVE.

...ITCZ...
ITCZ AXIS FROM 10N86W TO 09N90W TO 10N98W TO 09N106W TO 11N140W. 
ISOLATED MODERATE CONVECTION WITHIN 90 NM OF AXIS FROM 117W TO 
134W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WITHIN 
300 NM S OF AXIS BETWEEN 84W AND 103W. 

...DISCUSSION...

AN UPPER TROUGH CURRENTLY N OF AREA WILL AMPLIFY ALONG 
135W...WITH THE LOW LEVEL COMPONENT SETTLING S INTO N WATERS 
OVER THE NEXT TWO DAYS AND DISSIPATING WITH LITTLE FANFARE. NW 
SWELL PENETRATING THE FAR NW WATERS MAY BRIEFLY ALLOW SEAS TO 
APPROACH THE 8 FT MARK...BUT WINDS ARE EXPECTED TO BE WELL UNDER 
20 KT.  ELSEWHERE OVER WATERS N OF 20N...AN UPPER LEVEL 
ANTICYCLONE IS STRETCHED ACROSS THE REGION AND LARGE SCALE 
SUBSIDENCE CAN BE FOUND.  BROKEN TO OVERCAST STRATOCUMULUS 
CLOUDS COVER THE AREA N OF 20N W OF 115W.

A SLOW MOVING MID TO UPPER LEVEL INVERTED TROUGH S OF 20N 
BETWEEN 115W AND 125W WILL SLOW THE W PROGRESS OF THE TROPICAL 
WAVE CURRENTLY ALONG 118W AND CARRY IT ON A MORE N TRACK OVER 
THE NEXT FEW DAYS. DEEP CONVECTION WITH THIS SYSTEM WILL BE 
LIMITED DUE TO THE INCREASED VERTICAL SHEAR.

BROAD MID LEVEL CYCLONIC CIRCULATION CAN BE FOUND OVER WATERS E 
OF 100W.  WITHIN THIS REGION...TWO TROPICAL WAVES ARE EXPECTED 
TO CONTINUE ON WESTWARD TRACKS.  THE WESTERN TROPICAL WAVE IS ON 
THE SOUTHERN EDGE OF THE LOW LEVEL TROUGHING OVER MEXICO IN 
BETWEEN THE GULF OF TEHUANTEPEC AND THE BAY OF CAMPECHE. STRONG 
N TO NE FLOW THROUGH MEXICO INTO THE GULF OF TEHUANTEPEC IS 
PRODUCING 20 TO 30 KT WINDS AND SEAS TO 10 FT N OF 12N BETWEEN 
93W AND 96W. UPPER LEVEL 40 KT EASTERLY FLOW IS EXPECTED TO PASS 
OVER THE WAVE N OF 10N...LIMITING DEEP CONVECTION HERE...WHILE 
UPPER LEVEL DIFFLUENT FLOW ON THE SOUTHERN EDGE OF THIS TROPICAL 
WAVE SHOULD MAKE THIS PORTION OF THE WAVE THE MORE FAVORABLE 
LOCATION FOR CONVECTION. THE TROPICAL WAVE CURRENTLY ALONG 86W 
IS UNDER A REGION OF MORE BROADLY DIFFLUENT FLOW AT THE 
MOMENT...BUT SHOULD ENCOUNTER SIMILAR CONDITIONS IN A DAY OR 
TWO AS IT PROGRESSES W.

$$
SCHAUER CLARK