000
AXPZ20 KNHC 291605
TWDEP 

TROPICAL WEATHER DISCUSSION                            
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1605 UTC TUE DEC 29 2015

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1545 UTC.   

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

ITCZ AXIS EXTENDS FROM 6N91W TO 06N107W TO 06N119W TO 06N131W TO
BEYOND 05N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS WITHIN 120 NM N OF THE AXIS BETWEEN 128W-131W.

...DISCUSSION...                                              

IN GENERAL...RATHER QUIET CONDITIONS CONTINUE ACROSS THE AREA AS
HIGH PRESSURE DOMINATES. A 1026 MB HIGH PRESSURE SYSTEM IS
CENTERED N OF THE DISCUSSION AREA NEAR 37N135W WITH A RIDGE
STRETCHING SE TO 32N130W TO NEAR 20N112W. HIGH PRESSURE COVERS
THE AREA N OF 20N W OF 120W. A WEAKENING SURFACE TROUGH
ASSOCIATED WITH A LARGE UPPER TROUGH THAT IS MOVING EASTWARD
ACROSS THE WESTERN U.S. IS ANALYZED OVER THE FAR NE PORTION OF
THE AREA EXTENDING FROM A 1006 MB LOW OVER FAR WESTERN ARIZONA
SSW TO FAR NW MEXICO...AND SW TO ACROSS THE NORTHERN GULF OF
CALIFORNIA AND BAJA CALIFORNIA NORTE TO JUST OFFSHORE THE
PENINSULA NEAR 26N117W. THE TROUGH IS WITHIN AN AREA OF MODERATE
TO STRONG UPPER SUBSIDENCE WHICH IS SUPPRESSING SHOWER AND TSTM
ACTIVITY FROM DEVELOPING ALONG OR NEAR THE TROUGH. THE TROUGH IS
FORECAST TO SHIFT EASTWARD OVER NW MEXICO AND DISSIPATE THIS
AFTERNOON. A TIGHT GRADIENT BETWEEN THE TROUGH AND THE 1026 MB
HIGH IS ALLOWING FOR NW 20-25 KT WINDS TO PRESENTLY EXIST N OF
29N BETWEEN 116W-121W WITH SEAS IN THE 8-10 FT RANGE. THE WIND
CONDITIONS ARE FORECAST TO DIMINISH 15-20 KT THIS AFTERNOON AS
THE TROUGH DISSIPATES. SIMILAR WINDS OVER THE FAR NORTHERN PART
OF THE GULF OF CALIFORNIA ARE FORECAST TO DIMINISH 10-15 KT 
THIS AFTERNOON AS THE TROUGH DISSIPATES.

THE PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE CENTERED N OF
THE AREA AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ
CONTINUES TO SUPPORT AN AREA OF FRESH TO STRONG TRADE WINDS FROM
08N-21N W OF 129W... AND FROM 09N-15N BETWEEN 124W-129W WITH
SEAS IN THE 8 TO 10 FT RANGE...EXCEPT FOR HIGHER SEAS OF 10 TO
11 FT PRIMARILY IN NW SWELL FROM 14N-21NW W OF 135W. THE 1026 MB
HIGH N OF THE AREA IS FORECAST TO GRADUALLY SHIFT EASTWARD
THROUGH THU WHILE A WEAK LOW-LEVEL PERTUBATION THAT DEVELOPS
FROM A MID/UPPER TROUGH CURRENTLY BETWEEN 110W-120W TRACKS
WESTWARD WHILE BECOMING MORE NOTICEABLE AS A SURFACE TROUGH
ALONG A POSITION ROUGHLY FROM 14N122W TO 10N124W BY EARLY WED.
THE PRESSURE GRADIENT BETWEEN THIS FEATURE AND RIDGING N OF THE
ITCZ REGION WILL INDUCE NE 20-25 KT WINDS WITH SEAS IN THE RANGE
OF 9 TO 10 FT WITHIN 150-180 NM W OF THE TROUGH THROUGH 48 HOURS
AS IT REACHES TO NEAR 124W/125W BY THEN. AN EXTENSIVE AREA OF
MIXED NE AND NW SWELL WITH PRODUCED SEAS OF 8-11 FT EXISTING TO
N OF 09N BETWEEN 121W-129W...AND N OF 05N W OF 129W WILL SHRINK
IN COVERAGE WHILE SLOWLY SHIFTING SOUTHWARD THROUGH 48 HOURS AT
WHICH TIME IT WILL BE FORECAST TO BE PRESENT ELSEWHERE AWAY FROM
THOSE CONDITIONS RELATED TO THE SURFACE TROUGH WITHIN 360 NM
EITHER SIDE OF A LINE FROM 14N112W TO 12N127W TO 10N131W TO
08N140W WITH HIGHEST SEA UP TO 10 FT FROM 11N-13N BETWEEN 117W
AND 126W.

SOUTHERLY SWELL WILL BRING 8 FT SEAS TO THE EQUATOR BETWEEN 108W
AND 119W LATE TONIGHT AND N OF THE EQUATOR BY WED MORNING. THESE
8 FT SEAS WILL SHIFT W THROUGH WED NIGHT AND PERSIST THROUGH THU.

GAP WINDS...

GULF OF TEHUANTEPEC...N-NE 20-25 KT WINDS THROUGH GULF WITH SEAS
6-8 FT WILL QUICKLY DIMINISH TO 10-15 KT WITH SEAS OF 4-5 FT
THIS AFTERNOON...AND REMAIN THAT WAY INTO EARLY WED. BY LATE WED
NIGHT....ANOTHER GAP WIND PULSE IS EXPECTED TO BEGIN FOLLOWED BY
ANOTHER GALE FORCE GAP WIND EVENT FRI NIGHT AS A REINFORCING
PUSH OF COLD AIR OCCURS ACROSS THE WESTERN GULF OF MEXICO.

GULF OF PAPAGAYO...STRONG TO GALE FORCE EASTERLY TRADE WIND FLOW
ACROSS THE SW CARIBBEAN SEA IS RESULTING IN PULSES OF STRONG
EASTERLY GAP WINDS THROUGH THE GULF OF PAPAGAYO THAT WILL
DIMINISH EARLY THIS AFTERNOON. THESE WINDS WILL CONTINUE TO
PULSE DURING THE OVERNIGHT HOURS THROUGH SAT. THE CARIBBEAN
WINDS WILL ALSO SEND PULSES OF MODERATE TO FRESH NORTHERLY GAP
WINDS ACROSS THE ISTHMUS OF PANAMA INTO THE GULF OF PANAMA
DURING THE EVENING TO EARLY MORNING HOURS THROUGH SAT.

$$
AGUIRRE