000
AXPZ20 KNHC 070918
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU MAR 07 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM A 1010 MB LOW PRES NEAR 07N85W 
TO 02N90W TO 03N100W. THE ITCZ CONTINUES FROM 03N100W TO 05N120W 
TO 06N132W TO 03N140W. SCATTERED MODERATE CONVECTION IS NOTED  
FROM 09N TO 11N BETWEEN 124W AND 128W. SIMILAR CONVECTION IS 
NEAR 08N132W...AND WITHIN 30 NM EITHER SIDE OF THE AXIS W OF 
138W.

...DISCUSSION...
A WEAK 1021 MB HIGH PRES CENTERED NEAR 26N122W EXTENDS A RIDGE  
ACROSS THE NORTHERN PORTION OF FORECAST AREA INTERRUPTED BY A 
WEAKENING TROUGH THAT RUNS FROM 30N121W TO 26N127W. THE HIGH 
PRES WILL MOVE E-SE OVER THE NEXT 24 HOURS WHILE SLIGHTLY 
WEAKENING AS A LOW PRES SYSTEM DEVELOPS AND MOVES SOUTH JUST W 
OF THE COAST OF CALIFORNIA. THIS LOW PRES WILL BRING AN AREA OF 
20-25 KT W TO NW WINDS TO THE FAR NE PART OF FORECAST REGION... 
PARTICULARLY N OF 28N E OF 125W ON FRI AND SAT INCLUDING FRESH 
TO STRONG SW TO W WINDS IN THE NORTHERN GULF OF CALIFORNIA. THE 
LOW PRES WILL MOVE INLAND LATER ON FRI AND A NEW HIGH PRES WILL 
TAKE CONTROL OF MARINE CONDITIONS ACROSS THE FORECAST WATERS. AS 
HIGH PRES BUILDS IN...EXPECT AN INCREASE IN THE AERIAL EXTENT OF 
THE TRADE WINDS BY SAT. MARINE GUIDANCE SUGGESTS NE TO E WINDS 
OF 20-25 KT COVERING THE AREA FROM 06N TO 17N W OF 115W BY SAT 
AFTERNOON. 

A WEAK TROUGH REMAINS EMBEDDED IN THE ITCZ AND IS ANALYZED FROM 
09N130W TO 5N134W ON THE 0600 UTC SURFACE MAP. A FEW SHOWERS ARE 
NOTED ON EITHER SIDE OF THE TROUGH AXIS. THE TROUGH WILL 
CONTINUE TO MOVE WWD AND WEAKEN OVER THE NEXT FEW DAYS.

GAP WINDS...
THE 0404 UTC HI RESOLUTION ASCAT PASS PROVIDED OBSERVATIONS OF 
30-40 KT NLY WINDS ACROSS THE GULF OF TEHUANTEPEC WHERE A GALE 
WARNING REMAINS IN EFFECT. WINDS WILL DIMINISH BELOW GALE FORCE 
THIS AFTERNOON. EXPECT BUILDING SEAS OF 12-15 FT WITH THIS GAP 
WIND EVENT. SEAS WILL SPREAD DOWNWIND FROM THE TEHUANTEPEC AREA 
AS NE SWELL. WINDS ARE FORECAST TO DIMINISH BELOW 20 KT THIS 
EVENING THEN WILL INCREASE AGAIN TO 25 KT BY FRI MORNING. 

PULSING OF NOCTURNAL WINDS ARE EXPECTED ACROSS THE GULF OF 
PAPAGAYO REACHING 20-30 KT FROM 0600 TO 1200 UTC...WITH SEAS OF 
8-10 FT THROUGH AND DOWNWIND OF THE GULF. BASED ON MARINE 
GUIDANCE...THE FRESH TO STRONG WINDS WILL COVER THE AREA FROM 
08N TO 11N E OF 90W. 

THE REGIONAL WATERS ARE MAINLY DOMINATED BY LONG PERIOD NW SWELL 
AND NE WIND WAVES ASSOCIATED WITH THE GAP WIND EVENTS. SEAS OF 
9-11 FT CAN BE FOUND W OF LINE FROM 30N120W TO 08N130W WITH SEAS 
OF 8-9 FT ELSEWHERE N OF 05N W OF 115W. SEAS WILL GRADUALLY 
SUBSIDE ACROSS THE NW WATERS BUT WILL REMAIN IN THE 8 T0 10 FT 
RANGE WITHIN THE AREA OF INCREASING TRADE WINDS.  

$$
GR