000
AXPZ20 KNHC 290333
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED OCT 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 
0230 UTC.

...THE ITCZ...
THE ITCZ AXIS CAN BE FOUND ALONG A LINE FROM 7N77W TO 06N80W TO 
10N107W TO 10N125W TO 08N140W. SCATTERED MODERATE CONVECTION 
LIES WITHIN 180 NM S AND 45 NM N OF AXIS BETWEEN 116W AND 120W. 


...DISCUSSION...

THE MID TO UPPER LEVEL PATTERN OVER THE SUBTROPICAL PORTION OF 
THE DISCUSSION ZONE CURRENTLY SPORTS A RIDGE BOOKENDED BY A 
TROUGH MOVING INTO THE NW WATERS AND A TROUGH OVER NORTHEAST 
WATERS OFF THE BAJA PENINSULA.  SOME HIGH LEVEL CLOUDS HAVE 
INFILTRATED THE NW PART OF THE AREA AND ISOLATED SHALLOW 
CONVECTION CAN BE FOUND OFF THE SOUTHERN BAJA...BUT OVERALL 
SUBSIDENCE IS STILL DOMINANT IN MUCH OF THE SUBTROPICS. THE
PATTERN IS PROGRESSIVE...WITH A SHARP AND ELONGATED UPPER TROUGH 
N AND W OF THE ZONE PUSHING E AND DRAGGING A COLD FRONT ACROSS 
NW WATERS WED. THIS FRONT WILL WEAKEN ON FRI AS THE MAIN 
SYSTEM...CUT OFF FROM THE NORTHERN STREAM FLOW...IS LIFTED 
NORTHWARD IN RESPONSE TO A NEW SHOT OF MID LEVEL ENERGY PASSING 
INTO THE SOUTHWESTERN EDGE OF THE BROAD TROUGH OVER THE 
NORTHEASTERN PACIFIC.

IN THE TROPICS...A LOW LEVEL TROUGH EMBEDDED IN THE ITCZ ALONG 
110W IS SUPPORTING SCATTERED MODERATE WITHIN 120 NM OF TROUGH 
ALONG 110W FROM 09N TO 15N AS WELL AS SCATTERED MODERATE 
ISOLATED STRONG FROM 10N TO 13N BETWEEN 111W AND 114W AHEAD OF 
THE TROUGH.  MAIN CAUSE FOR THE INCREASED CONVECTION IS 
DUE THE UPPER DIFFLUENT PATTERN E OF AN UPPER TROUGH. THIS 
FEATURE WILL BE MOVING INTO A SLIGHTLY LESS FAVORABLE 
ENVIRONMENT SO ANY DEVELOPMENT WOULD BE SLOW TO OCCUR. 

GAP WINDS...
THE TIGHT PRESSURE GRADIENT BETWEEN A STRONG EARLY SEASON COLD 
FRONT OVER THE SW ATLC/NW CARIBBEAN AND RIDGING EXTENDING SOUTH 
OVER MEXICO FROM A 1031 MB HIGH OVER THE ARKLATEX HAS PRODUCED A 
STRONG TEHUANTEPEC EVENT.  THE SURFACE PRESSURE GRADIENT OVER 
SOUTHERN MEXICO IS AS MUCH AS 16 MB OVER A 180 NM DISTANCE. A 
HI-RES QSCAT PASS FROM AROUND 1252 UTC REVEALED 50 KT MAX WINDS. 
UNFORTUNATELY...THE NEXT EXPECTED QSCAT PASS WILL MISS THE GULF 
OF TEHUANTEPEC AND THERE HAVE BEEN NO SHIP OBSERVATIONS TO 
CONFIRM THE STORM FORCE WINDS SINCE EARLIER TUE...BUT SINCE THE 
PRESSURE GRADIENT HAS SHOW LITTLE RELAXATION...WILL CONTINUE TO 
WARN FOR STORM FORCE CONDITIONS IN THE NEAR TERM.  WINDS ARE 
EXPECTED TO FALL BELOW STORM FORCE WED MORNING AS THE HIGH 
PRESSURE WEAKENS AND SHIFTS EAST ACROSS THE SOUTHEASTERN CONUS 
AND THE COLD FRONT WEAKENS OVER THE CARIBBEAN.  HOWEVER...GALE 
FORCE WINDS ARE LIKELY FOR MUCH OF THE WEEK. 

THE QSCAT PASS FROM 2344 UTC SHOWS WINDS IN THE 20 TO 25 KT 
RANGE BLEEDING THROUGH CENTRAL AMERICA N OF 12N BETWEEN 88W AND 
91W AS WELL AS THROUGH THE GULF OF PAPAGAYO.  WHILE THE WIND 
SPEEDS HERE DO NOT WARRANT WARNINGS...THEY ARE EXPECTED TO HOVER 
OVER 20 KT FOR MUCH OF THE WEEK.

$$
SCHAUER CLARK