000
AXPZ20 KNHC 131554
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT DEC 13 2008

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1515 UTC.

...ITCZ...
FROM 06N77W TO 07N88W TO 07N113W TO 12N127W TO 08140W. SCATTERED 
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS WITHIN A 30 NM 
RADIUS OF 09N110W...FROM 05N TO 06N BETWEEN 89W AND 90W...FROM 
11N TO 12N BETWEEN 115W AND 117W...AND FROM 10N TO 11N BETWEEN 
132W AND 133W.

...DISCUSSION...

THE GAP WINDS...
A PARTIAL ASCAT PASS AROUND 13/0330 UTC REVEALED 30 KT AT THE 
SWATH EDGE TO THE WEST OF THE EXPECTED CORE WINDS IN THE GULF
OF TEHUANTEPEC. A GALE WARNING REMAINS IN PLACE FOR THE GULF
OF TEHUANTEPEC...BASED ON THIS DATA AND SUFFICIENT NORTHERLY
FUNNELING THAT IS EVIDENT IN THE LOW-LEVEL CLOUDS.
THE WINDS SHOULD SUBSIDE QUICKLY TODAY AS SOUTHERLY RETURN FLOW
BEGINS IN THE WESTERN GULF OF MEXICO. NORTHEASTERLY WINDS ALSO
ARE BLOWING OVER THE GULFS OF PAPAGAYO AND FONSECA TONIGHT.
THE SHIP 9HJG9 REPORTED 32 KT NEAR THE GULF OF PAPAGAYO AND
THE SHIP P3GY9 REPORTED 28 KT NEAR THE GULF OF FONSECA AT 06Z.
THESE REPORTS ARE IN AGREEMENT WITH AN EARLIER ASCAT PASS.
THESE GAP WINDS SHOULD DIMINISH DURING THE NEXT COUPLE OF DAYS
AS THE FRONT IN THE WESTERN CARIBBEAN SEA DISSIPATES. 

ELSEWHERE...
A MIDDLE TO UPPER LEVEL TROUGH IS DIGGING SOUTHWARD PASSING 
THROUGH 33N127W TO 19N130W. ONE SHORTWAVE TROUGH AFTER ANOTHER
ONE IN A ROW WILL CONTINUE TO DEEPEN THE TROUGH DURING THE NEXT
FEW DAYS...SUPPORTING A COUPLE OF COLD FRONTS MOVING INTO THE
NORTHEASTERN CORNER OF THE DISCUSSION AREA. THE GFS MODEL BRINGS
NORTHERLY 20 KT WINDS RIGHT TO 30N BUT NOT SOUTH OF 30N. THE 
NOGAPS MODEL PUTS A LITTLE OF BIT OF 20 KT WINDS TO 30N WEST
OF 120W AT THE END OF 48 HOURS. THE UKMET MODEL PUTS 20 KT
WINDS ONLY NORTH OF 29N BETWEEN 116W AND 119W AT 18 HOURS AND
AT THE END OF 24 HOURS...ONLY. LONG PERIOD NORTHERLY SWELL
COMBINED WITH SHORT PERIOD WIND WAVES WILL CREATE CONFUSED AND 
QUITE ELEVATED SEAS LATE THIS WEEKEND AND EARLY NEXT WEEK OFF 
THE NORTHERN BAJA COAST.

UPPER LEVEL ANTICYCLONIC FLOW ROTATES AROUND A CENTER NEAR 
32N141W.

A SEPARATE MIDDLE TO UPPER LEVEL TROUGH IS ALONG 28N122W TO
A CYCLONIC CIRCULATION CENTER NEAR 24N136W TO 12N138W. BROAD 
UPPER LEVEL ANTICYCLONIC WIND FLOW IS NORTH OF THE EQUATOR 
BETWEEN THE 28N122W 12N138W TROUGH AND CENTRAL AMERICA.

THE SURFACE PRESSURE GRADIENT IS TIGHTEST IN THE FAR WESTERN 
SECTION...BETWEEN STRONG MID-LATITUDE HIGH PRESSURE AND
A WEAK TROUGH FROM THE ITCZ ALONG 17N124W TO A 1011 MB LOW 
PRESSURE CENTER NEAR 12N126W TO 08N127W. THIS IS LEADING TO
NORTHEASTERLY TRADEWINDS NEAR 20 KT NORTH OF 07N WEST OF 130W.
THESE WINDS ARE EXPECTED TO WEAKEN DURING THE NEXT COUPLE OF
DAYS AS THE RIDGE ERODES IN RESPONSE TO LOW PRES TO ITS WEST.

$$
MT