000
AXPZ20 KNHC 282129
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN SEP 28 2008

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 2115 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 84W N OF 4N MOVING W 10 KT. SCATTERED 
MODERATE CONVECTION NOTED WITHIN 180 NM EITHER SIDE OF THE WAVE 
AXIS TO THE COAST OF PANAMA...AND OVER THE N END OF THE WAVE 
OVER EASTERN HONDURAS AND NICARAGUA.

TROPICAL WAVE N OF 5N ALONG 94W WITH A 1008 MB LOW NEAR 12N. 
WAVE WAS MOVING W 10 KT. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION ASSOCIATED WITH THIS WAVE COVERS THE AREA FROM 6N TO 
14N BETWEEN 90W AND 104W. VISIBLE SATELLITE IMAGERY INDICATED 
LOW LEVEL CYCLONIC TURNING ALONG THE WAVE AXIS NEAR 12N. IN 
ADDITION STRONG WINDS OF 25-30 KT IN THE GULF OF TEHUANTEPEC ARE 
FUNNELING SWD W OF THE AREA OF CYCLONIC TURNING/LOW PRES.

TROPICAL WAVE FROM 07N TO 18N ALONG 108W MOVING W 10 KT. 
SCATTERED WEAK CONVECTION IS NOTED WITHIN 120 NM E OF WAVE AXIS 
FROM 16N TO 18N.

TROPICAL WAVE FROM 06N TO 15N ALONG 120W 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
CONFINED TO WITHIN 90-120 NM OF THE ITCZ.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N85W TO 12N92W TO 10N97W TO 
11N107W TO 11N115W TO 11N125W TO 12N132W TO 11N140W. SCATTERED 
MODERATE ISOLATED STRONG WITHIN 180 NM S OF THE AXIS BETWEEN 91W 
AND 100W. SCATTERED MODERATE WITHIN 180 NM S OF THE AXIS BETWEEN 
91W AND 107W...AND WITHIN 60 NM N OF THE AXIS BETWEEN 115W AND 
124W.

...DISCUSSION...

A NEGATIVELY TILTED MID TO UPPER LEVEL TROUGH WITH NO 
SIGNIFICANT SENSIBLE WEATHER IMPACTS AT THE SURFACE EXTENDS FROM
A CYCLONIC CIRCULATION NEAR 32N120W THROUGH 30N128W 25N126W TO
20N128W APPEARS TO BE SHEARING OUT TO THE NORTH OF THE 
STATIONARY UPPER LEVEL ANTICYCLONE CENTERED NEAR 22N111W. AN 
ADDITIONAL KICKER FOR THIS TROUGH IS A LARGER STRONGER TROUGH TO 
THE NW OF THE AREA WHICH IS SLATED TO MOVE INTO THE AREA BY LATE 
MON/TUE. WINDS AND SEAS ARE FCST TO INCREASE TO THE 20 TO 30 KT 
RANGE OVER FAR NW WATERS TONIGHT AND MON IN ADVANCE OF A COLD 
FRONT WHICH IS EXPECTED TO MOVE INTO THE AREA MON NIGHT. MULTI 
GRID WAVE WATCH MODELS ARE FCSTG SEAS FCST 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 TROPICAL WAVE LIES 
ALONG 120W AND RATHER DIFFICULT TO TRACK IN THE FACE OF THE AREA 
OF SW TO W LOW LEVEL FLOW. 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 WITH A 
1232 UTC HIGH RESOLUTION QUIKSCAT PASS INDICATING WINDS OF 25-30 
KT IN THE AREA. A SUBSEQUENT 1538 UTC ASCAT PASS INDICATED 25 KT
WINDS IN THE AREA. THESE WINDS ARE ALSO SPILLING SWD WEST OF THE 
LOW PRES NEAR 12N94W. THESE WINDS ARE EXPECTED TO CONTINUE FOR 
THE NEXT 48 HOURS.  

$$
COBB