000
AXPZ20 KNHC 250340
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED NOV 25 2009

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 
0300 UTC.

...ITCZ...

AXIS ANALYZED FROM 08N79W TO 08N86W TO 05N98W TO 08N110W TO 
08N140W. SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 120 
NM S OF AXIS BETWEEN 107W AND 109W.   

...DISCUSSION...

A SHORTWAVE MID TO UPPER LEVEL TROUGH EXTENDS FROM 31N117W TO 
21N126W TO 17N135W WHICH WILL SHIFT EASTWARD AND WILL CUTOFF 
JUST OFF THE BAJA COAST NEAR 26N115W BY EARLY THU AS IT 
ENCOUNTERS AN UPPER RIDGE EXTENDING FROM THE U.S. ROCKIES TO 
NORTHERN MEXICO. THIS WILL INITIALLY HAVE LITTLE IMPACT ON 
SENSIBLE WEATHER HOWEVER IT WILL RESULT IN A MORE AMPLIFIED 
PATTERN OVER THE DISCUSSION AREA AS WELL AS OVER DOWNSTREAM/ 
ADJACENT AREAS. ANOTHER MID TO UPPER LEVEL TROUGH IS LOCATED NW 
OF THE DISCUSSION AREA FROM 40N147W TO 34N166W. THIS TROUGH WILL 
PUSH A SURFACE COLD FRONT INTO THE FAR NW PORTION OF OUR AREA 
LATE THU NIGHT INTO EARLY FRI WITH N-NW WINDS INCREASING TO 20 
TO 25 KT BEHIND THE FRONT. THE SWATH OF THESE STRONGER WINDS 
WILL EXPAND ACROSS THE N PORTION OF THE WATERS AS A TIGHT PRES 
GRADIENT BECOMES ESTABLISHED BETWEEN DEEP HIGH PRES TO OUR N AND 
LOWER PRES ASSOCIATED WITH THE ITCZ. IN ADDITION...A NEW SET OF 
NW SWELL WILL ARRIVE BEHIND THE FRONT AND LONG PERIOD SEAS WILL 
BUILD UP TO 16 FT BY FRI INTO THE WEEKEND.

OTHERWISE...EARLIER ASCAT AND WINDSAT PASSES CONTINUED TO SHOW A 
LARGE SWATH OF FRESH TO STRONG TRADE WINDS OVER THE DISCUSSION 
AREA MAINLY FROM 14N TO 21N W OF 128W. THESE WINDS ARE SOUTH OF 
A 1025 MB SURFACE HIGH PRES CENTERED NEAR 35N131W AT 00 UTC. A 
2222 UTC JASON ALTIMETER PASS INDICATED SEAS OF 8 TO 11 FT IN 
THE AREA OF FRESH TO STRONG TRADES...ALTHOUGH A PORTION OF THESE 
SEAS ARE RELATED TO PERSISTENT LONG PERIOD NW SWELL. 

STRONG DIURNALLY DRIVEN CONVECTION CONTINUES ALONG AND JUST 
INLAND OF THE COASTS OF COSTA RICA AND PANAMA DUE TO AFTERNOON 
SEABREEZE INITIALIZATION AND CONVERGENCE WITH INLAND TOPOGRAPHIC 
FEATURES. THIS ACTIVITY IS NOW GRADUALLY PUSHING W AND OFFSHORE 
THIS EVENING AND WILL CONTINUE TO DO SO INTO THE OVERNIGHT HOURS 
BEFORE WEAKENING AS LAND BREEZE CIRCULATIONS BECOME MORE 
PREDOMINANT. TO THE W...A WEAK AREA OF LOW PRES IS CENTERED NEAR 
08N88W. CONVECTION THAT HAD EARLIER DEVELOPED AROUND THIS 
FEATURE HAS SINCE DISSIPATED AS MORE STABLE AND DRY AIR BECOMES 
ADVECTED INTO THE CIRCULATION AS INDICATED BY WATER VAPOR 
SATELLITE IMAGERY.

...GAP WINDS...

NE TO E WINDS IN THE 20 TO 25 KT RANGE CONTINUE IN THE GULF OF 
PAPAGAYO AND IMMEDIATE SURROUNDING WATERS MAINLY DUE TO DRAINAGE 
FLOW OFF THE CENTRAL AMERICA COAST. THESE CONDITIONS ARE 
EXPECTED TO PERSIST THROUGH THE REMAINDER OF THE WEEK.

NW TO N WINDS IN THE GULF OF CALIFORNIA N OF 28N CONTINUE TO BE 
IN THE 20 TO 30 KT RANGE DUE TO A TIGHT PRES GRADIENT IN PLACE 
BETWEEN HIGH PRES OVER THE U.S. GREAT BASIN...A TROUGH OF LOW 
PRES ALONG THE COAST OF THE E GULF OF CALIFORNIA AND A HIGH PRES 
RIDGE W OF THE BAJA PENINSULA. THIS PATTERN AND THESE STRONG 
WINDS ARE EXPECTED TO PERSIST THROUGH THE NEXT 36-42 HOURS AND 
THEN WILL DIMINISH AS THE PRES GRADIENT RELAXES.

A STRONG SURFACE COLD FRONT WILL PUSH INTO THE S GULF OF MEXICO 
LATE TONIGHT INTO EARLY WED. THIS WILL ENHANCE GAP WIND FLOW 
FROM THE S GULF OF MEXICO ACROSS THE ISTHMUS OF TEHUANTEPEC AND 
THROUGH THE GULF OF TEHUANTEPEC...WHERE STRONG NORTHERLY FLOW 
CAN BE EXPECTED BY WED EVENTUALLY REACHING GALE FORCE LEVEL BY 
WED NIGHT.

$$
LEWITSKY