000
AXPZ20 KNHC 010327
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT NOV 01 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 
0200 UTC.

...ITCZ...
THE ITCZ IS CENTERED ALONG AN AXIS FROM 09N78W TO 09N86W TO 
06N106W TO 09N119W TO 08N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION CAN BE FOUND WITHIN 90 NM OF THE AXIS E OF 86W 
AND WITHIN 90 NM N AND 60 NM S OF THE AXIS FROM 88W AND 94W.

...DISCUSSION...

THE SURFACE LOW ACCOMPANYING THE TROUGH ALONG 98W IS SUPPORTING 
SCATTERED MODERATE CONVECTION WITHIN 150 NM NW AND 120 NM NE 
QUADRANT OF THE LOW PRESSURE CENTER NEAR 07N98W.  THIS SYSTEM 
WAS LIKELY SPURRED BY THE ATMOSPHERIC VORTICITY FROM THE LOW TO 
MID LEVEL JET THROUGH THE GULF OF PAPAGAYO AND IS NOW BEING 
ENHANCED BY ADDED VORTICITY SUPPLIED BY THE JET THROUGH THE GULF 
OF TEHUANTEPEC. THE QSCAT PASS FROM 0006 UTC REVEALS THAT THE 
REGION OF 20 TO 25 KT WINDS WITH THIS LOW HAS GROWN SINCE THE 
LAST SCATTEROMETER HIT...AN ASCAT PASS AT 0320 UTC FRI.  ANY 
GENERATION OF DEEP CONVECTION WITH THE SYSTEM WILL HAVE TO 
BATTLE 25 TO 35 KT E TO NE SHEAR ALOFT.

THE STRONG PRESSURE GRADIENT THAT HAS BEEN PRESENT OVER CENTRAL 
AMERICA FOR SEVERAL DAYS IS FINALLY SHOWING SOME SIGNS OF 
RELAXATION...BUT WINDS IN THE GULF OF TEHAUNTEPEC ARE STILL 
EXPECTED TO REMAIN GALE FORCE FOR THE NEXT TWO DAYS. A QSCAT 
PASS FROM 0006 UTC SUPPORTS THE CURRENT GALE WARNING BUT DOES 
SHOW SOME SHRINKING OF THE AREA OF GALE FORCE WINDS.  SLACKENING 
WILL BE FASTER TO OCCUR TO THE SOUTH WITH WINDS EXPECTED TO FALL 
BELOW 20 KT AND SEAS BELOW 8 FT IN THE GULFS OF FONSECA AND 
PAPAGAYO BY LATE TODAY AND BY MON....RESPECTIVELY.

A BROAD MID TO UPPER LEVEL TROUGH HAS BEEN OVER THE N EASTERN 
PACIFIC FOR THE LAST SEVERAL DAYS BRINGING NW SWELL TO TO MUCH 
OF THE REGION W OF 120W.  A REINFORCING SHOT TO THIS BROAD 
TROUGH...IN THE FORM OF A COLD FRONT AT THE SURFACE...IS 
CURRENTLY APPROACHING NW WATERS AND WILL HELP TO CARRY THE BROAD 
TROUGH EASTWARD.  MEANWHILE...THE UPPER LEVEL ANTICYCLONE S OF 
THE BAJA PENINSULA NEAR 15N110W IS FORECAST TO PASS WESTWARD TO 
THE SOUTH OF THE TROUGH...LIMITING THE ENCROACHMENT OF THE 
TROUGH TO THE SOUTH.  EXPECT THE SURFACE COLD FRONT TO DISSIPATE 
BY SUN...BUT LEAVE ELEVATED SEAS GENERALLY IN THE 8 TO 12 FT 
RANGE IN NW WATERS PRIMARILY N OF 15N AND W OF 125W ON SUN.  THE 
EASTERN PROGRESS OF THE COLD FRONT OVER N WATERS WILL PUSH THE 
HIGH PRESSURE CURRENTLY CENTERED NEAR 27N119W EASTWARD AS 
WELL...INCREASING THE PRESSURE GRADIENT IN THE VICINITY OF THE 
BAJA AND THE GULF OF CALIFORNIA WHERE WINDS ARE EXPECTED TO BE 
IN THE 20 TO 25 KT RANGE OVER THE WEEKEND.

BROAD UPPER LEVEL DIFFLUENCE ON THE SOUTHWESTERN SIDE OF THE 
ANTICYCLONE S OF THE BAJA PENINSULA IS HELPING THE CAUSE FOR 
CONVECTION NEAR A SURFACE TROUGH ALONG 121W.  SCATTERED MODERATE 
CONVECTION CAN BE FOUND WITHIN 90 NM OF THE TROUGH AXIS ALONG 
121W FROM 12N TO 16N AS WELL AS JUST W OF THIS AREA FROM 11N TO 
13N BETWEEN 122W AND 125W.

$$
SCHAUER CLARK