000
AXPZ20 KNHC 240925
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1005 UTC TUE DEC 24 2013

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 FEATURE...

GULF OF TEHUANTEPEC...A SCATTEROMETER PASS AT 0418 UTC SHOWED 
NORTHERLY WINDS OF 45 KT IN THE GULF WHILE A SHIP CROSSING THE 
AREA REPORTED 50 KT. STRONG HIGH PRES BUILDING S INTO SRN MEXICO 
WILL FUNNEL WINDS THROUGH CHIVELA PASS INTO GULF OF TEHUANTEPEC 
DURING THE NEXT 48 HOURS. STORM FORCE WINDS ARE EXPECTED TO 
PERSIST THROUGH LATE THIS MORNING...THEN GALE FORCE WINDS WILL 
CONTINUE TO BLOW ACROSS THIS GAP WIND REGION THROUGH WED AT 1800 
UTC WHEN WINDS ARE FORECAST TO REACH 30 KT. SEAS WILL CONTINUE 
TO BUILD AND PEAK AT 18-20 FT THIS MORNING. FRESH TO STRONG 
WINDS WILL EXTEND WESTWARD TO REACH AS FAR AS 110W WITH SEAS TO 
8 FT BY WED MORNING. THE NAM REGIONAL MODEL SUGGESTS THAT WINDS 
WILL DIMINISH BELOW GALE FORCE WED AFTERNOON AND WED EVENING BUT 
WILL INCREASE AGAIN TO GALE FORCE WED NIGHT THROUGH FRI. THE GFS 
GLOBAL MODEL INDICATES SIMILAR MARINE CONDITIONS THROUGH FRI. SO 
DECIDE TO INCREASE WINDS AGAIN TO MINIMAL GALE FORCE AT 26/0600 
UTC...THE END OF THE FORECAST PERIOD. A REINFORCING HIGH PRES 
MOVING INTO THE STATE OF TEXAS WILL ALLOW THE PRES GRADIENT TO 
TIGHT ENOUGH ACROSS THE ISTHMUS OF TEHUANTEPEC TO PRODUCE 
ANOTHER ROUND OF GALE FORCE WINDS WED NIGHT THROUGH FRI.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS FROM 07N78W TO 08N84W TO 06N100W 
WHERE LOW LEVEL WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS 
TO 06N120W TO BEYOND 09N140W. SCATTERED MODERATE CONVECTION IS 
NOTED WITHIN 90 NM N OF ITCZ AXIS W OF 133W.

...DISCUSSION... 

HIGH PRESSURE CENTERED WELL N OF THE AREA NEAR 44N130W EXTENDS A 
RIDGE SE ACROSS THE N WATERS TO NEAR 18N110W. PRES GRADIENT 
BETWEEN THE RIDGE AND LOWER PRES ASSOCIATED WITH THE ITCZ IS 
PRODUCING AN AREA OF ENHANCED TRADES W OF 120W. AN UPPER LEVEL 
TROUGH LOCATED BETWEEN 145W AND 150W WILL SHIFT EASTWARD THROUGH 
WED AND INDUCE A SURFACE TROUGH EXPECTED TO DEVELOP BETWEEN 130-
135W THIS MORNING. A SMALL AREA OF FRESH TO STRONG WINDS WILL BE 
ASSOCIATED WITH THE TROUGH FORECAST TO MOVE WESTWARD OVER THE 
NEXT COUPLE OF DAYS.  

LONG PERIOD NW SWELLS WITH WAVE PERIODS BETWEEN 18-20 SEC ALONG 
ITS LEADING EDGE WILL CONTINUE TO SPREAD SOUTHEASTWARD COVERING 
MUCH OF THE DISCUSSION AREA W OF 100W TODAY. THIS SWELL WILL MIX 
WITH NE SEAS GENERATED DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
LATER TODAY...CREATING A LARGE AREA OF 8-12 FT SEAS FROM 05N TO 
14N BETWEEN 93W AND 110W BY WED AFTERNOON.

WINDS WILL CONTINUE TO PULSE DURING THE NEXT COUPLE OF DAYS 
THROUGH THE GULF OF PAPAGAYO...PEAKING AT NEAR 25 KT DURING 
OVERNIGHT AND EARLY MORNING HOURS FROM NOCTURNAL DRAINAGE FLOW. 
SEAS WILL BUILD TO NEAR 8 FT DURING EACH PERIOD OF HIGHER WINDS. 

GULF OF CALIFORNIA...THE PRESSURE GRADIENT BETWEEN STRONG HIGH 
PRESSURE OVER THE GREAT BASIN AND TROUGHING OVER NW MEXICO IS 
SUPPORTING FRESH TO STRONG NW WINDS IN THE GULF OF CALIFORNIA N 
OF 25N. SCATTEROMETER DATA PROVIDED OBSERVATIONS OF THESE WIND 
SPEEDS. THE HIGH N OF THE AREA WILL START TO WEAKEN THIS 
MORNING...RELAXING THE PRESSURE GRADIENT OVER THE GULF OF 
CALIFORNIA WITH WINDS DIMINISHING TO 20 KT OR LESS ACROSS THE 
REGION LATER TODAY. 
 
$$
GR