000
AXPZ20 KNHC 181542
TWDEP 

TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1605 UTC MON MAR 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N78W TO 07N85W TO 
05N95W. THE ITCZ AXIS WAS ANALYZED FROM 05N95W TO 02N120W...THEN 
CONTINUES FROM 03N130W TO 02N140W. SCATTERED MODERATE CONVECTION 
PERSISTS WITHIN 60 NM S OF AXIS E OF 95W.

...DISCUSSION...                                                 
A BROAD LONG WAVE UPPER TROUGH MOVING INTO THE CENTRAL UNITED 
STATES AND NORTH CENTRAL MEXICO HAS COME IN PHASE WITH A 
PERSISTENT UPPER TROUGH OFF THE SOUTHERN PORTION OF THE BAJA 
PENINSULA EXTENDING AS FAR S AS THE EQUATOR AT 115W. JET DYNAMICS 
ALOFT AT THE BASE OF THE TROUGH CONTINUES TO SUPPORT SCATTERED 
CONVECTION FROM 05N TO 08N BETWEEN 105W AND 108W. 

DEEP LAYER RIDGING W OF THE TROUGH ALONG 135W HAS BEEN 
SUPPORTING SURFACE HIGH PRES CENTERED NEAR 20N125W. PERSISTENT 
FRESH TO STRONG N FLOW BETWEEN THE HIGH PRES AND THE COAST OF 
CALIFORNIA HAD BEEN GENERATING NORTHERLY SWELL IN EXCESS OF 8 FT 
REACHING AS FAR S AS 28N BETWEEN 118W AND 125W. AN ALTIMETER 
PASS EARLIER THIS MORNING INDICATED SEAS TO 8 FT WERE STILL 
PRESENT IN THIS AREA. THE SUPPORTING UPPER RIDGE IS CURRENTLY 
BEING IMPINGED FROM THE WEST BY ANOTHER DEEP LAYER TROUGH MOVING 
EASTWARD TO THE NORTH OF HAWAII...THE SURFACE HIGH AS LARGELY 
DISSIPATED. THE SEAS TO 8 FT WILL SUBSIDE ACCORDINGLY THROUGH 
TODAY. 

A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH APPROACHING FROM 
THE WEST EXTENDS FROM 38N140W TO 30N140W TO 19N155W NEAR THE BIG 
ISLAND OF HAWAII. THE FRONT WILL DRIFT EASTWARD TODAY BEFORE 
STALLING AND WEAKENING FROM 35N130W TO 23N145W WED AS THE MAIN 
TROUGH LIFTS NE. FRESH SW WINDS AND SEAS TO 8 FT WILL PRECEDE 
THE FRONT COVERING THE PORTION OF THE DISCUSSION AREA N OF 28N W 
OF 135W. WEAK SURFACE HIGH PRES WILL BUILD ALONG 28N NEAR 120W 
AS THE MAIN TROUGHS LIFTS OUT...SUPPORTING MODERATE TO FRESH 
TRADE WINDS S OF 15N W OF 125W.

LOOKING AHEAD...HIGH PRES WILL CONTINUE TO BUILD IN THE NW 
PACIFIC IN THE WAKE OF THE UPPER TROUGH...AGAIN SUPPORTING FRESH 
TO STRONG NORTHERLY WINDS ALONG THE CALIFORNIA COAST...POSSIBLY 
REACHING AS FAR S AS THE NORTHERN COAST OF BAJA BY 
THU...FOLLOWED BY SEAS BUILDING TO 8 FT MAINLY N OF 28N E OF 
125W BY FRI.

$$
CHRISTENSEN