000
AXPZ20 KNHC 030957
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN JAN 03 2016

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.   

...SPECIAL FEATURES...

A COLD FRONT IS SWEEPING ACROSS THE NORTHERN PORTIONS OF THE
DISCUSSION AREA AND CURRENTLY EXTENDS FROM 30N126W TO 25N130W TO
21N140W. THE FRONT WILL MOVE E OF THE AREA AND DISSIPATE BY LATE
MON. DEEPENING LOW PRESSURE NORTH OF THE AREA IS TIGHTENING THE
PRESSURE GRADIENT OVER THE AREA ESPECIALLY N OF 27N W OF 137W.
AN EARLIER SHIP OBSERVATION JUST WEST OF THE AREA INDICATED
WINDS TO GALE FORCE. A MORE RECENT ASCAT SATELLITE PASS
INDICATED WINDS TO NEAR GALE FORCE AS WELL. THE ONGOING GALES
WILL PERSIST THROUGH THE NEXT SEVERAL HOURS THEN GRADUALLY
DIMINISH THROUGH THIS EVENING AS THE FRONT CONTINUES EAST AND
WEAKENS. THIS SYSTEM IS ALSO USHERING IN A NEW SET OF NW SWELLS
WITH COMBINED SEAS REACHING CLOSE TO 20 FT TONIGHT OVER THE FAR
NW PORTION OF THE AREA. SEAS OF 12 TO 18 FT WILL SPREAD EASTWARD
OVER THE AREA N OF 23N THROUGH LATE SUN.  

THE PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE BEHIND A
STATIONARY FRONT OVER THE GULF OF MEXICO AND LOWER PRESSURE IN
THE VICINITY OF THE EASTERN NORTH PACIFIC ITCZ IS HELPING TO
FUNNEL GALE FORCE WINDS OVER THE GULF OF TEHUANTEPEC. WINDS ARE
FORECAST TO PULSE TO  MINIMAL GALE FORCE THROUGH MON NIGHT. AS A
RESULT SEAS ARE FORECAST TO REMAIN IN THE 9 TO 13 FT RANGE.
 
SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFEP2/FZPN03 KNHC FOR MORE DETAILS ON BOTH GALE AREAS.

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

THE AXIS OF THE ITCZ EXTENDS FROM 03N94W TO 06N130W TO BEYOND
04N140W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 60 NM S
OF THE ITCZ BETWEEN 115W AND 130W. 

...DISCUSSION... 

N OF 15N E OF 120W...1018 MB HIGH PRES CENTERED NEAR 26N118W IS
SHIFTING SOUTH AND WEAKENING AHEAD OF A COLD FRONT APPROACHING
FROM THE WEST. THE NEGATIVELY TILTED UPPER TROUGH SUPPORTING THE
FRONT WILL LIFT TO THE NE THROUGH TONIGHT. THE COLD FRONT WILL
LOSE DEFINITION AS IT MOVES INTO BAJA CALIFORNIA NORTE BY
TONIGHT...WITH SW TO W WINDS OF 15 TO 20 KT PENETRATING GAPS
INTO THE NORTHERN GULF OF CALIFORNIA. THE MAIN IMPACT WILL BE
THE ACCOMPANYING SWELL...WITH SEAS 8 FT OR GREATER DUE TO NW
SWELL REACHING THE COAST OF BAJA CALIFORNIA NORTE BY LATE
MON...BAJA CALIFORNIA SUR AND THE REVILLAGIGEDO ISLANDS
TUE...AND NEAR CABO CORRIENTES AND THE ENTRANCE TO THE GULF OF
CALIFORNIA THROUGH MID WEEK. A SECOND COLD FRONT WILL REACH BAJA
CALIFORNIA NORTE TUE NIGHT...WITH A REINFORCING SHOT OF NW SWELL
WITH SEAS TO 12 FT FOLLOWING THROUGH MID WEEK. 

S OF 15N E OF 110W...STRONG TO NEAR GALE FORCE TRADE WINDS OVER
THE CARIBBEAN ARE FUNNELING THROUGH THE SAN JUAN RIVER VALLEY
BETWEEN COSTA RICA AND NICARAGUA AND EXITING AS GAP WINDS IN THE
GULF OF PAPAGAYO AND NEAR PUERTO SANDINO ON THE PACIFIC COAST OF
NICARAGUA. ENHANCED BY OVER NIGHT DRAINAGE EFFECTS...THE STRONG
GAP WINDS PLUMES ARE REACHING 240 NM DOWNSTREAM WITH SEAS TO 8
FT. THE STRONG WINDS IN THE CARIBBEAN WILL ALSO INDUCE PULSES OF
MODERATE TO FRESH NORTHERLY GAP WINDS ACROSS THE ISTHMUS OF
PANAMA INTO THE GULF OF PANAMA THROUGH THE REMAINDER OF THIS
MORNING. THESE PLUMES WILL DIMINISH ALTOGETHER LATER TODAY...BUT
A WEAKER PULSE IS EXPECTED TONIGHT. WEAKENING HIGH PRES N OF THE
AREA WINDS WILL ALLOW ONLY MARGINAL PULSES THEREAFTER THROUGH
MID WEEK. NE SWELL GENERATED FROM THE GAP WINDS WILL PROPAGATE
WESTWARD AND MERGE WITH NE SWELL GENERATED BY THE GULF OF
TEHUANTEPEC. 
 
ELSEWHERE...THE PASSAGE OF SUCCESSIVE COLD FRONTS NORTH OF 20N
HAS WEAKENED THE GRADIENT ENOUGH TO MAINTAIN GENERALLY MODERATE
TRADE WIND FLOW ACROSS THE DEEP TROPICS S OF 20N W OF 120W. A
WEAK UPPER TROUGH BETWEEN 120W AND 125W IS SUPPORTING MODEST
CONVECTION ALONG THE ITCZ BETWEEN 115W AND 130W. NW SWELL WITH
COMBINED SEA HEIGHTS 8 TO 10 FT WILL BUILD OVER THE AREA FROM
05N TO 15N W OF 125W THROUGH TUE. LOOKING AHEAD...THE HIGH PRES
WILL BUILD NORTH OF THE AREA STARTING MID WEEK...ALLOWING A
GRADUAL INCREASE IN TRADE WIND FLOW. SEAS WILL BUILD TO 12 FT
IN MIXED NW SWELL AND NE WIND WAVES.

$$
CHRISTENSEN