000
AXPZ20 KNHC 310326
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU DEC 31 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.   

...SPECIAL FEATURE...

THE NEXT PULSE OF N TO NE WINDS IN THE GULF OF TEHUANTEPEC IS
EXPECTED TO BEGIN WITHIN THE NEXT 6 HOURS OR SO WITH WINDS OF 20
TO 25 KT AT THE ONSET...INCREASING TO 30 KT DURING THE MAXIMUM
DRAINAGE FLOW THU MORNING. THESE WINDS ARE EXPECTED TO REMAIN
STRONG TO NEAR GALE FORCE WITH SEAS REACHING A MAX OF AROUND 11
FT UNTIL FRI EVENING. THEREAFTER...THE GFS AND UKMET MODELS ARE
IN AGREEMENT THAT THE NEXT GALE FORCE GAP WIND EVENT ARRIVES FRI
EVENING AS A REINFORCING PUSH OF COLD AIR SPREADS ACROSS THE
WESTERN GULF OF MEXICO. WINDS ARE FORECAST TO REACH 35 KT BY FRI
EVENING. INDICATIONS ARE THAT WINDS MAY REMAIN AT GALE FORCE
THROUGH THE WEEKEND. 

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

ITCZ AXIS EXTENDS FROM 06N85W TO 05N100W TO 07N120W TO 08N135W
TO BEYOND 05N140W. SCATTERED MODERATE FROM 09N TO 11N BETWEEN
109W AND111W. 

...DISCUSSION...                                              

HIGH PRESSURE DOMINATES MOST OF THE REGION WITH A 1025 MB HIGH
CENTERED N OF THE DISCUSSION AREA NEAR 36N128W. A RIDGE EXTENDS
FROM THE HIGH SE TO 32N123W TO NEAR 22N115W. THE PRESSURE
GRADIENT BETWEEN THIS HIGH PRESSURE AND LOWER PRESSURE IN THE
VICINITY OF THE ITCZ...AND WITH THE ADDED FACTOR OF A SURFACE
TROUGH ALONG A POSITION FROM 14N125W TO 09N129W CONTINUES TO
SUPPORT AN AREA OF FRESH TO STRONG TRADE WINDS WITHIN 180 NM W
OF THE TROUGH...AND ELSEWHERE FROM 10N TO 17N BETWEEN 125W AND
132W WITH SEAS IN THE 9-10 FT RANGE. 

A FAST-MOVING SHORTWAVE UPPER TROUGH ALONG 127W N OF 20N IS
GENERATING A VAST AREA OF MOSTLY MID TO HIGH CLOUDS N OF 15N E
OF 120W TO BAJA CALIFORNIA AND MEXICO WITHIN AN AREA OF STRONGLY
DIFFLUENT FLOW. THE TROUGH WILL SWEEP TOWARD BAJA CALIFORNIA BY
LATE THU/THU NIGHT. AS THE SHORTWAVE TROUGH PULLS OFF TO THE
NE...EXPECT THE SURFACE TROUGH TO WEAKEN AND DISSIPATE. THE HIGH
PRESSURE N OF THE AREA IS FORECAST TO GRADUALLY SHIFT EASTWARD
THROUGH THU AS A COLD FRONT MOVES INTO THE NW CORNER OF THE
DISCUSSION AREA OVERNIGHT TONIGHT.

THIS FRONT WILL WEAKEN AS IT REACHES A POSITION FROM NEAR
32N135W TO 24N140W BY LATE THU...THEN BECOME A DISSIPATING FRONT
FROM NEAR 32N129W TO 19N140W FRI. NW SWELL WILL FOLLOW INTO THE
NW CORNER OF THE AREA WITH RESULTANT SEAS OF 8-11 FT.
THE NWP MODELS ARE SUGGESTING THAT A STRONG COLD FRONT WILL MOVE
INTO THE NW PORTION OF THE AREA FRI NIGHT INTO SAT PRECEDED BY
STRONG SW WINDS AND BUILDING SEAS...AND FOLLOWED BY POSSIBLE
GALE FORCE W TO NW WINDS AS DEPICTED IN THE LATEST RUNS OF THE
GFS...ECMWF AND UKMET.   

CROSS-EQUATORIAL SWELL WITH SEAS OF 8-9 FT ARE S OF 02N BETWEEN
108W-119W. THIS AREA OF SWELL WILL GRADUALLY SHRINK IN AREA
THROUGH EARLY FRI. 

GAP WINDS...

GULFS OF PAPAGAYO AND PANAMA...STRONG TO GALE FORCE TRADES
ACROSS THE SW CARIBBEAN SEA IS RESULTING IN PULSES OF STRONG NE-
E GAP WINDS THROUGH THE GULF OF PAPAGAYO. THE MAXIMUM AREAL
EXTENT IS EXPECTED EARLY FRI WITH 20 TO 30 KT WINDS COVERING AN
AREA FROM 09N TO 12N E OF 92W...INCLUDING THE GULF OF PAPAGAYO.
THESE WINDS WILL BUILD SEAS TO 11 FT IN THE AREA. CARIBBEAN
WINDS WILL ALSO USHER 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.

$$
COBB