000
AXPZ20 KNHC 222152
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI DEC 21 2007

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.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG...6N77W 7N110W 
9N140W. SCATTERED MODERATE TO STRONG WITHIN 60 NM EITHER SIDE OF 
AXIS FROM 127W TO 137W.

...DISCUSSION...

W OF 105W...1033 MB SURFACE HIGH PRES IS CENTERED NEAR 34N129W. 
SCATTEROMETER DATA SHOW A LARGE AREA OF FRESH TO STRONG TRADES 
TO THE S OF THE HIGH PRES...COVERING MUCH OF THE AREA W OF 105W. 
STRONG NW FLOW ON THE EASTERN PERIPHERY OF THE HIGH PRES IS ALSO 
EVIDENT THROUGH THE GULF OF CALIFORNIA. ALOFT...A BROAD UPPER 
TROUGH EXTENDS FROM NRN BAJA TO NEAR 11N118W...AHEAD OF AN UPPER 
RIDGE ROUGHLY ALONG 135W. THE PATTERN WILL BECOME MORE AMPLIFIED 
AS A SERIES OF SHORT WAVE TROUGH MOVE N OF THE RIDGE IN THE FAR 
NE PACIFIC...AND DIG SE INTO CALIFORNIA AND THE SW U.S. GLOBAL 
MODELS SHOW A CUTOFF LOW FORMING EARLY NEXT WEEK NEAR GENERALLY 
20N130W...SETTING UP A BRIEF REX BLOCK BY MIDWEEK. WHAT THIS 
MEANS IS THAT THE STRONG SURFACE HIGH PRES WILL REMAIN IN PLACE 
FOR A FEW DAYS...AND THE FRESH TO STRONG TRADE WINDS WILL ALSO. 
DIVERGENCE ALOFT ALONG WITH LOW LEVEL CONVERGENCE IS AIDING 
DEVELOPMENT OF MODEST CONVECTION ALONG THE ITCZ AS NOTED ABOVE. 

E OF 105W...WEAK PRES PATTERN IS MAINTAINING GENERALLY LIGHT 
WINDS OVER THE AREA CURRENTLY. THIS WILL CHANGE SUNDAY AS A 
STRONG COLD FRONT PUSHES THROUGH THE GULF OF MEXICO...PROMPTING 
GALE CONDITIONS THROUGH THE GULF OF TEHUANTEPEC BY LATE SUNDAY. 
IN ADDITION...STRONG TRADES OVER THE CARIBBEAN SUN INTO EARLY 
NEXT WEEK WILL INCREASE ELY FLOW THROUGH THE GULF OF PAPAGAYO. 
WINDS WILL DIMINISH OVER THE TEHUANTEPEC AREA THROUGH MON AS 
HIGH PRES TO THE N SHIFTS EWD. THE FRESH TO STRONG ELY FLOW OVER 
THE PAPAGAYO AREA WILL PERSIST AT LEAST THROUGH MID WEEK. 
MEANWHILE...JUST AS THE TEHUANTEPEC AND PAPAGAYO EVENTS GET 
STARTED....MODERATE SW SWELL OF UP TO 5 FT WITH 14S PERIODS WILL 
MOVE INTO THE MEXICAN CENTRAL AMERICAN COASTS SUN AND MON.

$$
CHRISTENSEN