000
AXPZ20 KNHC 240333
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC SAT JAN 24 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 
0300 UTC. 

...SPECIAL FEATURES...                                          
A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC. WINDS 
IN THIS AREA WILL BEGIN TO INCREASE TONIGHT AS STRONG HIGH PRES 
BUILDS INTO SOUTHERN MEXICO BEHIND A COLD FRONT CURRENTLY MOVING 
ACROSS THE EASTERN BAY OF CAMPECHE. COLD DENSE AIR BEHIND THE 
FRONT WILL FUNNEL THROUGH THE CHIVELA PASS TO ACCELERATE ACROSS 
THE GULF OF TEHUANTEPEC. WINDS WILL QUICKLY REACH GALE FORCE BY 
EARLY SAT MORNING...WITH PEAK WINDS IN EXCESS OF 40 KT FORECAST 
TO PERSIST THROUGH SUN MORNING. EXPECT MAX SEAS TO 15-16 FT BY 
SAT AFTERNOON ASSOCIATED WITH THIS WIND EVENT. THIS IS FORECAST 
TO BE A LONG DURATION GALE FORCE GAP WIND EVENT. A RIDGE WILL 
PERSIST ALONG THE MEXICO COASTAL PLAINS TO SOUTH-CENTRAL MEXICO 
TO MAINTAIN A TIGHT PRES GRADIENT ACROSS THE ISTHMUS OF 
TEHUANTEPEC. A REINFORCING PUSH OF COLD AIR IS EXPECTED TO OCCUR 
ON MON FOLLOWED BY A STRONGER ONE ON WED. WINDS ARE FORECAST TO 
DIMINISH TO MINIMAL GALE FORCE SUN AFTERNOON AND EVENING THEN 
WILL INCREASE AGAIN TO 35-40 KT SUN NIGHT INTO MON MORNING. THIS 
PULSING OF WINDS IS EXPECTED ON TUE AND WED. THIS GAP WIND EVENT 
IS FORECAST TO CONTINUE THROUGH FRI MORNING. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH FROM 05N77W TO 06N90W TO 07N100W. ITCZ FROM 
07N100W TO 06N120W TO 07N140W. ISOLATED MODERATE CONVECTION FROM 
02N TO 04N BETWEEN 83W AND 85W. SIMILAR CONVECTION IS WITHIN 30 
NM EITHER SIDE OF ITCZ AXIS BETWEEN 116W AND 121W.

...DISCUSSION...                                                
A 1030 MB HIGH PRES CENTERED NEAR 39N128W EXTENDS A RIDGE 
SOUTHWARD TO COVER MOST OF THE DISCUSSION AREA N OF 18N. A WEAK 
SURFACE TROUGH...ASSOCIATED WITH A WELL DEFINED UPPER LOW 
CENTERED NEAR 19N127W...EXTENDS FROM 20N131W TO 14N133W 
PRODUCING ISOLATED TO SCATTERED SHOWERS. SCATTEROMETER DATA 
SHOWED AN AREA OF FRESH TO STRONG NE WINDS FROM 18N TO 22N 
BETWEEN 128W AND 135W DUE TO THE PRESSURE GRADIENT BETWEEN THE 
HIGH PRES TO THE NORTH AND THE TROUGH. MODERATE TO FRESH WINDS 
ARE NOTED ELSEWHERE ACROSS THE SOUTHERN PERIPHERY OF THE RIDGE.

AN AREA OF LARGE LONG PERIOD NW SWELL...ASSOCIATED WITH A COLD 
FRONT IN THE CENTRAL PACIFIC N OF HAWAII...IS SPREADING ACROSS 
THE NW WATERS. AN ALTIMETER PASS INDICATED SEAS TO 13 FT IN 
ASSOCIATION WITH THIS SWELL EVENT. THE COLD FRONT WILL ENTER THE 
FAR NW CORNER OF THE FORECAST REGION LATE SUN AND EXTEND FROM 
FROM 30N138W TO 26N140W BY SUN EVENING...FROM 30N135W TO 24N140W 
BY MON MORNING...THEN WEAKEN ACROSS THE NW WATERS MON NIGHT AND 
DISSIPATE INTO A TROUGH THROUGH TUE. 
 
HIGH PRES BUILDING OVER THE SOUTHWEST U.S. IN COMBINATION WITH A 
SURFACE TROUGH ACROSS NW MEXICO HAS TIGHTENED THE PRES GRADIENT 
IN THE GULF OF CALIFORNIA. WINDS ARE FRESH TO STRONG BETWEEN 25N 
AND 30N THIS EVENING. FRESH TO LOCALLY STRONG NW WINDS ARE 
EXPECTED TO PERSIST IN THE GULF OF CALIFORNIA THROUGH SAT NIGHT.

GAP WINDS...                                                
FRESH TO LOCALLY STRONG WINDS ARE EXPECTED TO INCREASE TO 25 KT 
SAT NIGHT AND SUN MORNING IN THE GULF OF PAPAGAYO AS HIGH PRES 
BUILDS ACROSS THE WESTERN CARIBBEAN. EXPECT ALSO FRESH NORTHERLY 
WINDS ACROSS THE GULF OF PANAMA SAT NIGHT INTO SUN MORNING.

$$ 
GR