000
AXPZ20 KNHC 290347
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON SEP 29 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 0315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 84W N OF 3N IS MOVING W ABOUT 13 KT. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF 
9N87W. OTHERWISE...ONLY ISOLATED SHOWERS ARE WITHIN 60 NM OF THE 
AXIS.

TROPICAL WAVE N OF 5N ALONG 94W WITH AN ASSOCIATED 1007 MB LOW 
NEAR 11N. THIS WAVE IS WAS MOVING W 7 KT. SCATTERED MODERATE
TO STRONG CONVECTION IS WITHIN 60 NM NW OF THE LOW. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM E OF THE
WAVE FROM 5N-9N. LAST VISIBLE SATELLITE IMAGERY SHOWED LOW-LEVEL
CYCLONIC TURNING ALONG THE WAVE AXIS NEAR 12N. IN ADDITION 
STRONG WINDS OF 25-30 KT IN THE GULF OF TEHUANTEPEC CONTINUE TO
FUNNELING SWD AND INTO THE WESTERN SEMICIRCLE OF THE LOW. GLOBAL
MODELS CONTINUE TO SUGGEST THAT THIS FEATURE WILL HOLD TOGETHER
AS IT MOVES IN A GENERAL WESTWARD DIRECTION OVER THE NEXT FEW 
DAYS.

TROPICAL WAVE FROM 6N TO 17N ALONG 107W IS MOVING W AROUND 10 KT.
A WEAK AND SMALL LOW CENTER IS ON THE WAVE AXIS NEAR 17N. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF 
A LINE FROM 16N108W TO 18N109W. ISOLATED WEAK CONVECTION IS 
ELSEWHERE WITHIN 60 NM W OF THE WAVE AXIS.

TROPICAL WAVE FROM 05N TO 16N ALONG 121W IS MOVING W 10-15 KT. 
THE 1010 MB LOW PRES NOTED EARLIER ALONG THE WAVE NEAR 16N HAS 
DISSIPATED. CONVECTION ASSOCIATED WITH THIS TROPICAL WAVE IS 
REFERRED BELOW UNDER ITCZ.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N85W TO 12N92W TO 10N97W TO
11N107W TO 11N115W TO 10N126W TO 12N135W TO 10N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE 
AXIS BETWEEN 85W-100W...AND WITHIN 30 NM OF THE AXIS BETWEEN
120W-125W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF
THE AXIS BETWEEN 110W-120W.

...DISCUSSION...

A NEGATIVELY TILTED MID TO UPPER LEVEL TROUGH WITH NO 
SIGNIFICANT SENSIBLE WEATHER IMPACTS AT THE SURFACE EXTENDS INTO
THE AREA THROUGH 32N126W TO 25N126W TO 20N128W. A LARGER
AND STRONGER TROUGH TO THE NW OF THE AREA WHICH IS FORECAST TO 
MOVE INTO THE AREA BY LATE MON/TUE. WINDS AND SEAS ARE FCST TO 
INCREASE TO THE 20-30 KT RANGE OVER FAR NW WATERS TONIGHT AND 
MON IN ADVANCE OF A COLD FRONT WHICH IS EXPECTED TO MOVE INTO 
THE NW CORNER OF THE AREA EARLY MON EVENING. MULTI GRID WAVE 
WATCH MODELS ARE FORECASTING SEAS TO BUILD TO 12-15 FT OVER THE 
FAR NW CORNER OF THE DISCUSSION AREA. 

LOW TO MID LEVEL MONSOONAL TROUGHING FROM 18N105W TO 10N130W IS 
PROVIDING A FOCUS FOR THE AVAILABLE TROPICAL MOISTURE WITH A
BROAD AREA OF WIDELY SCATTERED MODERATE CONVECTION NOTED ON 
SATELLITE IMAGERY. WITHIN THIS REGION...A VERY WEAK 1010 MB LOW 
NEAR 15N113W IS MOVING W 5 KT WITH SW-W WINDS OF 20 KT TO ITS
S AND WITH SEAS 8-10 FT IN SW SWELL.

BROAD SW-W LOW LEVEL FLOW IS NOTED FROM 10N-15N BETWEEN 
105W-123W. THIS AREA IS ANALYZED AS A LARGE AREA OF LOW PRES ON 
THE SURFACE MAP. UPPER LEVEL DIFFLUENCE IS EXPECTED TO ENHANCE 
THE CONVECTION IN THE AREA OVER THE NEXT 24 HOURS OR SO. 

AN ENHANCED PRESSURE GRADIENT BETWEEN A SURFACE LOW AND 
ASSOCIATED TROUGHING IN THE VICINITY OF THE WESTERN YUCATAN 
PENINSULA AND RIDGING EAST OF THE SIERRA MADRE/WESTERN BAY OF 
CAMPECHE AND THROUGH THE CHIVELAS PASS IS FUNNELING MODERATE TO 
STRONG N TO NE SURFACE WINDS INTO THE GULF OF TEHUANTEPEC AS 
OBSERVED ON A QUIKSCAT PASS FROM JUST PAST 0100 UTC WHERE WINDS 
OF 25-30 KT WERE REVEALED. THESE WINDS ARE ALSO SPILLING SWD 
WEST OF THE LOW PRES NEAR 11N94W. THESE WINDS ARE EXPECTED TO 
CONTINUE FOR THE NEXT SEVERAL DAYS.

$$
AGUIRRE