Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 170905
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU APR 17 2014

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 
0815 UTC. 

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

THE ITCZ EXTENDS FROM 11N97W TO 05N120W TO BEYOND 05N140W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM NORTH OF THE 
ITCZ AXIS BETWEEN 130W AND 140W. 

...DISCUSSION...                                               

A MID TO UPPER SHORT WAVE TROUGH REACHES FROM 35N128W TO 26N140W 
TO THE HAWAIIAN ISLANDS. THE MID TO UPPER TROUGH WILL SHIFT 
EASTWARD N OF 28N...MOVING ACROSS THE COAST OF SOUTHERN 
CALIFORNIA AND THE NORTHERN BAJA CALIFORNIA PENINSULA FRI NIGHT. 
THE SUBTROPICAL RIDGE EXTENDS FROM 1026 MB HIGH PRES CENTERED 
NEAR 33N140W TO 15N110W. THE PASSAGE OF THE MID TO UPPER SHORT 
WAVE TROUGH IS ENHANCING FRESH TO STRONG NORTHERLY FLOW ALONG 
THE COAST OF SOUTHERN CALIFORNIA ON THE EASTERN PERIPHERY OF THE 
RIDGE...RESULTING IN AN AREA OF SHORT PERIOD NORTHERLY SWELL TO 
8 FT REACHING AS FAR SOUTH AS 28N BETWEEN 118W AND 125W THAT IS 
EXPECTED TO PERSIST INTO SATURDAY. 

THE PASSAGE OF THE MID TO UPPER SHORT WAVE TROUGH WILL ALSO 
ENHANCE A SURFACE TROUGH OVER THE GULF OF CALIFORNIA...AND AID 
DEVELOPMENT OF WEAK LOW PRES OVER N CENTRAL MEXICO BY LATE 
SATURDAY. THIS IN TURN WILL ALLOW FRESH SOUTHERLY FLOW ACROSS 
THE NORTHERN GULF OF CALIFORNIA LATE FRI INTO SAT. 

SOUTH OF THE RIDGE AXIS...ASCAT SATELLITE DATA OVER THE PAST 
SEVERAL HOURS INDICATED A LARGE AREA OF MODERATE TO FRESH TRADE 
WINDS FROM 06N TO 20N WEST OF 125W. CONCURRENT ALTIMETER 
SATELLITE DATA INDICATED SEAS TO 9 FT...VERIFYING WAVEWATCH III 
MODEL INITIALIZATIONS SHOWING SEAS TO 9 FT IN A BROAD MIX OF 
SWELL IN THIS AREA. TRADE WIND CONVERGENCE IS INTERACTING WITH 
FAVORABLE WINDS ALOFT TO SUPPORT AREAS OF MODEST CONVECTION 
ALONG THE ITCZ BETWEEN 130W AND 140W. 

WEAK UPPER FORCING ON THE SOUTHEAST SIDE OF A BROAD UPPER TROUGH 
EXTENDING FROM SOUTH CENTRAL MEXICO TO 00N105W WAS ENHANCING 
SCATTERED SHOWERS AND THUNDERSTORMS WEST OF COSTA RICA BETWEEN 
07N TO 10N EAST OF 95W. WEAK SURFACE WINDS HAS ALLOWED THESE 
SHOWERS AND THUNDERSTORMS TO LARGELY DISSIPATED OVER THE PAST 
SIX HOURS. 

AN AREA OF 8 TO 9 FT PERSISTS FROM 06N TO 12N BETWEEN 98W AND 
105W IN NE SWELL...THE REMNANTS OF AN EARLIER STORM FORCE GAP 
WIND EVENT THROUGH THE GULF OF TEHUANTEPEC A FEW DAYS AGO. THIS 
IS EXPECTED TO PROPAGATE WEST SLOWLY AND BUT SUBSIDE BELOW 8 FT 
BY EARLY FRI MORNING. 

LOOKING AHEAD FOR THE GULF OF TEHUANTEPEC...ANOTHER MID TO UPPER 
LEVEL DISTURBANCE OVER THE SOUTHERN ROCKIES WILL AMPLIFY AS IT 
MOVES EASTWARD INTO THE SOUTHERN PLAINS AND LOWER MISSISSIPPI 
VALLEY THROUGH FRIDAY. AN ASSOCIATED COLD FRONT WILL THROUGH 
GULF OF MEXICO FRI INTO SAT. THIS WILL BE FOLLOWED BY STRONG 
HIGH PRES OVER THE WESTERN GULF OF MEXICO THAT IN TURN WILL 
ALLOW A BRIEF SHOT OF GALE FORCE WINDS INTO THE GULF OF 
TEHUANTEPEC BY EARLY SATURDAY MORNING. 

$$ 
CHRISTENSEN