Tropical Weather Discussion
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000
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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