000
AXPZ20 KNHC 200321
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED FEB 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

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

THE MONSOON TROUGH IS ALONG 03N78W TO 01N84W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 01N84W TO 05N110W TO 06N125W 
TO 06N140W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 12N 
BETWEEN 127W AND 133W.

...DISCUSSION...

1034 MB SURFACE HIGH PRES IS NW OF THE DISCUSSION WATERS NEAR 
36N149W WITH A RIDGE EXTENDING SE THROUGH 32N140W TO 18N106W. A 
TIGHT PRES GRADIENT IS SW OF THE RIDGE AXIS SUPPORTING FRESH TO 
STRONG WINDS FROM ROUGHLY 07N TO 23N W OF 130W...AND FROM 15N TO 
22N BETWEEN 125W AND 130W. SEAS OF 8-11 FT IN MIXED NE WIND 
WAVES AND LONG PERIOD NW SWELL. THE AREA OF FRESH TO STRONG 
TRADES AND ASSOCIATED SEAS WILL NOT CHANGE MUCH IN COVERAGE OR 
STRENGTH DURING THE NEXT 24-48 HOURS AS THE RIDGE QUICKLY 
REBUILDS IN ACROSS THE NW WATERS IN THE WAKE OF A DISSIPATING 
COLD FRONT.

THAT COLD FRONT IS FORECAST TO DROP S OF 30N LATE TONIGHT INTO 
EARLY WED WITH FRESH TO NEAR GALE FORCE WINDS BEHIND IT S OF 30N 
AND NW SWELL UP TO 16 FT BY WED AFTERNOON/EVENING. THE FRONT 
WILL QUICKLY LOSE ITS DEFINITION OVER THE NORTHERN WATERS BY WED 
NIGHT AS IT PROGRESSES SOUTHWARD. THE LARGE NW SWELL WILL 
GRADUALLY SUBSIDE TO 8-12 FT OVER THE NORTHERN PORTION BY THU 
EVENING. 

THIS FRONT WILL ALSO AID FRESH TO STRONG SW-W WINDS IN THE FAR 
NORTHERN GULF OF CALIFORNIA THROUGH EARLY WED NIGHT. THESE WINDS 
WILL DIMINISH THEREAFTER AS THE GRADIENT WEAKENS AND THE FRONT 
DISSIPATES.

GAP WINDS...
FRESH TO STRONG WINDS WILL CONTINUE TO PULSE IN THE GULF OF 
PAPAGAYO...WITH THE STRONGEST WINDS OCCURRING DURING THE 
OVERNIGHT AND EARLY MORNING HOURS WITH ENHANCEMENT BY NOCTURNAL 
DRAINAGE FLOW. ASSOCIATED SIGNIFICANT WAVE HEIGHTS WILL PEAK 
AROUND 9 FT. A LONG PLUME OF MODERATE TO FRESH EASTERLY WINDS 
ALONG WITH SEAS OF UP TO 8 FT IN MIXED NE AND NW SWELL WILL 
PERSIST WELL DOWNWIND OF PAPAGAYO FROM 05N TO 11N BETWEEN 97W 
AND 115W THROUGH EARLY WED.

HIGH PRES OVER EASTERN MEXICO AND LOWERING PRES S OF THE GULF OF 
TEHUANTEPEC WILL PRODUCE ENOUGH OF A PRES GRADIENT ACROSS THE 
ISTHMUS OF TEHUANTEPEC TO SUPPORT A BRIEF PULSE OF 20 TO 30 KT 
GAP WINDS THROUGH WED MORNING.

$$
LEWITSKY