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AXPZ20 KNHC 201608
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN APR 20 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOONAL CIRCULATION STILL NOT YET EVIDENT ACROSS THE AREA. ITCZ EXTENDS FROM 03N77W TO 05N89W TO 06N106W TO 03N117W TO 03N130W TO BEYOND 04.5N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 60 NM N AND 210 NM S OF AXIS E OF 108W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION NOTED WITHIN 210 NM N OF AXIS W OF 123W.




...DISCUSSION... THE LATEST WEATHER OBSERVATIONS AT 1445 UTC FROM SALINA CRUZ ON THE PACIFIC SIDE OF THE ISTHMUS OF TEHUANTEPEC INDICATED N WINDS AT 10 KT GUSTING TO 19 KT...AN INDICATION THE STRONG GAP FLOW HAS BEGUN TO SUBSIDE...AS FORECAST BY GLOBAL MODELS. A 0900 UTC SHIP REPORT BY THE JPO VELA PASSING WELL DOWNWIND FROM THE GULF OF TEHUANTEPEC INDICATED WINDS AROUND 30 KT...LIKELY THE PEAK OF THE OVERNIGHT DRAINAGE FLOW. WINDS AND SEAS WILL CONTINUE TO SUBSIDE QUICKLY THROUGHOUT THE AFTERNOON AND ARE EXPECTED TO FALL BELOW 20 KT WITH SEAS LESS THAN 8 FT BY THIS EVENING...WITH WINDS THEN BECOMING VARIABLE FOR THE NEXT SEVERAL DAYS.

FRESH GAP WIND FLOW ALSO THROUGH THE GULF OF PAPAGAYO THIS MORNING IS PULSING TO AROUND 20 KT WITH GUSTS TO 25 KT OVERNIGHT...BUT HAS BEGUN TO DIMINISH THIS MORNING. THE FRESH FLOW IS EXPECTED AGAIN TONIGHT INTO EARLY MON MORNING BEFORE DIMINISHING AFTER SUNRISE.

ELSEWHERE AN UPPER TROUGH EXTENDING FROM THE SOUTHWEST UNITED STATES TO 20N120W WILL SHIFT EASTWARD ACROSS THE BAJA PENINSULA AND THE GULF OF CALIFORNIA THROUGH TONIGHT. UPPER FORCING ON THE SE SIDE OF THE TROUGH IS SUPPORTING SCATTERED CONVECTION FROM FROM 10N TO 14N BETWEEN 99W AND 109W.

1026 MB HIGH PRES IS CENTERED N OF THE AREA NEAR 35N131W...AND IS SHIFTING E AHEAD OF A LARGE AND STRONG FRONTAL SYSTEM MOVING ACROSS THE NE PACIFIC. THIS FRONT WILL REMAIN N OF THE AREA AND MOVE INTO THE PACIFIC COAST OF THE U.S. TONIGHT...WITH A STRONG PULSE OF NW SWELL MOVING THROUGH THE AREA WATERS TODAY THROUGH TUESDAY. SEAS AREA ALREADY 8-10 FT IN THIS NW SWELL NW OF LINE FROM 30N133W TO 26.5N140W AND WILL REACH CENTRAL PORTIONS OF THE AREA BY TUE MORNING.

FARTHER SOUTH...THE RIDGE IS SUPPORTING 20 TO LOCALLY 25 KT TRADE WIND FLOW FROM 09N TO 16N W OF 132W....WHERE TRADE WIND CONVERGENCE IS SUPPORTING SCATTERED MODERATE TO STRONG CONVECTION ALONG AND S OF THE ITCZ DESCRIBED ABOVE W OF 123W. A 1030 MB HIGH WILL BUILD ACROSS THE AREA FROM THE NW LATE MON THROUGH TUE AND ACT TO BROADEN THE AREA OF FRESH TRADES FROM 08.5N TO 17N W OF 135W BY TUE MORNING.

NORTHERLY WINDS OFF THE PACIFIC COAST OF THE NORTHERN BAJA PENINSULA WILL INCREASE TO AT LEAST 20 KT BY LATE TUE INTO EARLY WED AS THE RIDGE BUILDS FROM THE WEST...AND LOW PRES DEEPENS OVER THE SW UNITED STATES AND NW MEXICO. THE LARGE AREA OF NW SWELL WILL DECAY BELOW 8 FT BY THIS TIME...ALTHOUGH 8 TO 11 FT SEAS WILL PERSIST N OF 25N E OF 125W BY MIDWEEK DUE TO THE ENHANCED FLOW OFF THE COAST OF THE NORTHERN BAJA PENINSULA.

THE GFS AND ECMWF HINT OF BRIEF PULSE OF FRESH WESTERLY FLOW INTO THE GULF OF CALIFORNIA ACROSS GAPS IN THE HILLY TERRAIN OF THE BAJA PENINSULA LATE TUE THROUGH WED.

LOOKING AHEAD TO LATE IN THE WEEK...WAVE MODELS SUGGEST LONG PERIOD SW SWELL IN EXCESS OF 8 FT WILL PROPAGATE NORTHWARD ACROSS THE EQUATOR...REACHING AS FAR NORTH AS 15N AND WITHIN 200 NM OF THE CENTRAL AMERICAN AND SOUTHERN MEXICAN COASTLINES BY LATE FRI.

$$ STRIPLING

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