000
AXPZ20 KNHC 301903 AAA
TWDEP 

TROPICAL WEATHER DISCUSSION...UPDATED 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1903 UTC WED DEC 30 2015

UPDATED TO INCLUDE MENTION OF WINDS BEHIND COLD FRONT FRI NIGHT
INTO SAT

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
1830 UTC.   

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

ITCZ AXIS EXTENDS FROM FROM 06N85W TO 04N98W TO 06N109W TO
06N120W TO05N131W TO BEYOND 05N140W. NO SIGNIFICANT CONVECTION
IS NOTED.

...DISCUSSION...                                              

HIGH PRESSURE DOMINATES MOST OF THE REGION WITH A 1026 MB HIGH
CENTERED N OF THE DISCUSSION AREA NEAR 36N129W. A RIDGE EXTENDS
FROM THE HIGH SE TO 32N123W TO NEAR 22N113W. 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 14N122W TO 09N124W CONTINUES TO
SUPPORT AN AREA OF FRESH TO STRONG TRADE WINDS WITHIN 180 NM W
OF THE TROUGH...AND 13N-19N BETWEEN 122W-137W WITH SEAS IN THE
9-10 FT RANGE...EXCEPT FOR A BATCH OF 10-11 FT SEAS ATTRIBUTED TO
LONG DURATION NW SWELL FROM 10N-20N BETWEEN 122W-136W. SCATTERED
MODERATE CONVECTION IS SEEN WITHIN 45 NM W OF THE TROUGH FROM 09N-11N.

A SHORTWAVE UPPER TROUGH ALONG 132W IS RAPIDLY MOVING EASTWARD.
THE TROUGH WILL MOVE OVER THE AFOREMENTIONED SURFACE TROUGH
TONIGHT AND EARLY THU. THIS WILL HELP MAINTAIN THE PRESENT
GRADIENT THAT IS PRODUCING FRESH TO STRONG NE TRADES W OF 
THE TROUGH WITH SEAS IN THE RANGE OF 9-10 FT. AS THE SHORTWAVE
TROUGH PULLS OFF TO THE NE THROUGH FRI...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. THIS FRONT WILL
WEAKEN AS IT REACHES A POSITION FROM NEAR 32N136W TO 26N140W BY
LATE THU NIGHT...THEN BECOME A DISSIPATING FRONT FROM NEAR
32N132W TO 23N140W FRI. NW SWELL WILL FOLLOW INTO THE NW CORNER
OF THE AREA WITH RESULTANT SEAS OF 8-9 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 EXPAND E TO E THROUGH THE
NEXT 24 HOURS...THEN BE CONFINED TO S OF 04N BETWEEN 111W-120W
BY EARLY FRI.

GAP WINDS...

GULF OF TEHUANTEPEC...THE NEXT PULSE OF N TO NE WINDS IN THE
GULF OF TEHUANTEPEC IS EXPECTED TO BEGIN LATE TONIGHT WITH WINDS
OF 20-25 KT WITH WINDS REACHING 30 KT EARLY ON THU. THESE WINDS
ARE EXPECTED TO REMAIN STRONG TO NEAR GALE WITH SEAS REACHING A
MAX OF AROUND 11 FT UNTIL THE NEXT GALE FORCE GAP WIND EVENT
ARRIVES LATE FRI NIGHT INTO SAT AS A REINFORCING PUSH OF COLD
AIR SPREADS ACROSS THE WESTERN GULF OF MEXICO.

GULFS OF PAPAGAYO AND PANAMA...STRONG TO GALE FORCE TRADES
ACROSS HE SW CARIBBEAN SEA IS RESULTING IN PULSES OF STRONG NE-E
GAP WINDS THROUGH THE GULF OF PAPAGAYO. THESE WINDS WILL
DIMINISH TO 15-20 KT THIS AFTERNOON...THEN RETURN AS STRONG NE
WINDS EARLY ON THU. THEY WILL DIMINISH AGAIN THU AFTERNOON...
AND MATERIALIZE THU NIGHT. THE 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.

$$
AGUIRRE