000
AXPZ20 KNHC 160915
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC TUE DEC 16 2014

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.  
      
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
           
THE MONSOON TROUGH EXTENDS FROM 09N84W TO 1009 MB LOW PRES NEAR 
06N89W TO 05N95W...WHERE IT TRANSITIONS TO AN ITCZ. THE ITCZ 
CONTINUES FROM 05N95W TO 10N125W TO 07N135W TO BEYOND 07N140W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 180 NM N OF THE 
ITCZ AXIS BETWEEN 110W AND 120W.

...DISCUSSION...

A COLD FRONT EXTENDS FROM 30N121W TO 24N130W WHERE IT BEGINS TO 
DISSIPATE TO 21N140W. RECENT SCATTEROMETER SATELLITE DATA 
INDICATED OF MODERATE TO FRESH NW WINDS BEHIND THE FRONT WITH 
LIGHT TO MODERATE SE WINDS AHEAD OF THE FRONT. SHIP 
OBSERVATIONS ALONG WITH EARLIER ALTIMETER SATELLITE PASSES 
INDICATED 10-15 FT SEAS W OF THE FRONT. LONG PERIOD NW SWELL 
DOMINATES MOST OF THE FORECAST REGION WITH ADDITIONAL PULSES 
CURRENTLY PROPAGATING ACROSS MOST OF THE WATERS W OF 110W. SEAS 
OF 8 FT OR GREATER COVER THE AREA W OF A LINE FROM THE COAST OF 
BAJA CALIFORNIA NORTE TO 02N140W. REINFORCING SWELL ACCOMPANYING 
THE FRONT WILL PROPAGATE ACROSS THE REGION MAINTAINING SEAS TO 8 
FT W OF 110W BY MID WEEK. LOOKING AHEAD...ANOTHER LONG PERIOD NW 
SWELL TRAIN WITH SEAS REACHING 12 TO 15 FT WILL MOVE INTO THE NW 
PART OF THE AREA FROM THE N CENTRAL PACIFIC BY LATE WEEK.

THE POSITION OF THE FRONT HAS TEMPORARILY DISTRIBUTED THE NORMAL 
SUBTROPICAL RIDGE POSITION OVER THE WATERS N OF 20N. THE 
RESULTING WEAK PRES GRADIENT IS MAINTAINING GENERALLY LIGHT TO 
MODERATE TRADE WINDS OVER THE DEEP TROPICS. THIS WILL CHANGE AS 
HIGH PRES BUILDS EASTWARD BEHIND THE FRONT...ALLOWING TRADE 
FRESH TO STRONG TRADE WINDS FROM 10N TO 15N W OF 130W BY WED.

AN ASCAT SATELLITE PASS FROM 05 UTC INDICATED A WEAK TROUGH 
ALONG THE ITCZ FROM 09N TO 13N ALONG 125W. DIVERGENCE ALOFT 
AHEAD OF THE MID/UPPER TROUGH SUPPORTING THE COLD FRONT TO THE 
NORTH HAD BEEN MAINTAINING AREAS OF SHOWERS AND FEW 
THUNDERSTORMS N OF THE ITCZ TO 15N BETWEEN 110W AND 125W. MODEL 
GUIDANCE INDICATES THIS PATTERN WILL PERSIST THROUGH MID WEEK.

GAP WINDS...HIGH PRES BUILDING OVER THE NORTHERN GULF OF MEXICO 
BY MID WEEK WILL DELIVER FRESH TO STRONG GAP WINDS INTO THE GULF 
OF TEHUANTEPEC AND GULF OF PAPAGAYO TONIGHT INTO EARLY WED 
MORNING...ENHANCED IN PART BY LOCAL DRAINAGE EFFECTS. THESE 
WINDS WILL DIMINISH BY LATE WED MORNING. THE LATEST RUN OF THE 
GFS MODEL SUGGESTS NORTHERLY WINDS IN THE 20-30 KT RANGE IN THE 
GULF OF TEHUANTEPEC WITH SEAS BRIEFLY REACHING 8 FT. EXPECT NE 
TO E WINDS OF 20-25 KT AND 6 TO 7 FT IN THE GULF OF PAPAGAYO BY 
LATE TONIGHT/EARLY WED MORNING BEFORE SUBSIDING.

$$
CHRISTENSEN