000
AXPZ20 KNHC 020417
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC SAT MAY 02 2015

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0200 UTC. 

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

THE MONSOON TROUGH EXTENDS FROM 08.5N93W TO 08.5N116W TO 06N140W. 
SCATTERED MODERATE TO STRONG CONVECTION NOTED FROM 02N TO 11N 
BETWEEN 80W AND 93W. SCATTERED MODERATE TO STRONG CONVECTION 
NOTED WITHIN 210 NM N AND 360 NM S OF TROUGH BETWEEN 105W AND 
121W...AND WITHIN 120 NM N AND 210 NM S OF TROUGH W OF 123W.  

...DISCUSSION...    

ZONAL FLOW ALOFT CONTINUES ACROSS MOST OF THE AREA N OF 15N 
TONIGHT...WITH A GENERALLY FLAT RIDGE ACROSS THE TROPICS S OF 
15N. AN ELONGATED UPPER LEVEL TROUGH CONTINUES TO SINK SLOWLY 
SOUTHWARD ACROSS NW PORTIONS...FROM NORTHERN CALIFORNIA TO A MID 
TO UPPER LEVEL CYCLONE NEAR 28N138W...CONTINUING SW IN TUTT LIKE 
FASHION TO THE NW HAWAIIAN ISLANDS. SE OF THE CYCLONE...MID TO 
UPPER FLOW BACKS SW TO S AND INTO BAJA CALIFORNIA AND THE DESERT 
SW OF THE U.S. AND OVER A BROAD UPPER RIDGE ACROSS THE WESTERN 
U.S.  THE UPPER TROUGH AND CYCLONE ARE FORECAST TO DRAG EWD AND 
INTO SOUTHERN CALIFORNIA BY MON AND BRING STRONG JET DYNAMICS 
ACROSS NE PORTIONS OF THE AREA AND INTO NORTHERN BAJA CALIFORNIA 
BY MON MORNING. 

AT THE SURFACE...A STRONG RIDGE CONTINUES ACROSS W PORTIONS... 
CENTERED ON A 1032 MB HIGH NEAR 39N146W...EXTENDING E THE W 
COAST OF THE U.S. AND SE TO NEAR 24N120W. THE PRES GRADIENT 
BETWEEN THE HIGH AND LOWER PRES ALONG THE MONSOON TROUGH HAS 
WEAKENED MODESTLY IN THE PAST 24-36 HOURS...AND MODERATE TO 
FRESH NE TRADEWINDS PREVAIL ACROSS THE AREA W OF 130W. AFTERNOON 
SCATTEROMETER PASSES SUGGESTED WINDS GENERALLY LESS THAN 20 KT E 
OF 120W ACROSS THE AREA THIS AFTERNOON...WITH THE LONE EXCEPTION 
A NORTHERLY GAP WIND EVENT IN THE GULF OF TEHUANTEPEC. 

ACTIVE CONVECTION ACROSS THE AREA E OF 90W...AND NEAR THE 
MONSOON TROUGH W OF 105W...HAS DIMINISHED SOMEWHAT THIS 
EVENING...LIKELY AS PART OF A DIURNAL TREND. HOWEVER...ACTIVE 
CONVECTION IS EXPECTED TO CONTINUE E OF 110W THROUGH TONIGHT AND 
THEN SLOWLY DIMINISH OVER THE WEEKEND.

ACROSS THE GULF OF TEHUANTEPEC...STRONG NORTHERLY WINDS REMAIN 
NEAR 20 KT THIS EVENING...WHILE SEAS DOWNWIND TO 12N REMAIN 7 TO 
9 FT WITH BUILDING SW SWELL. A WEAK HIGH PRES RIDGE IS EXPECTED 
TO CONTINUE ACROSS THE GULF OF MEXICO OVER THE WEEKEND AND 
MAINTAIN LIGHT TO MODERATE NE WINDS FUNNELING ACROSS THE ISTHMUS 
OF TEHUANTEPEC. THIS SCENARIO IS EXPECTED TO PRODUCE NORTHERLY 
WINDS OF 15-20 KT DURING THE DAYS INCREASING TO 20-30 KT TONIGHT 
AND AGAIN SATURDAY NIGHT...BEFORE DIMINISHING LESS THAN 20 KT 
SUNDAY AFTERNOON THROUGH MON.
 
LARGE SW SOUTHERN HEMISPHERIC SWELL HAS MOVE N-NE ACROSS S 
PORTIONS OF THE AREA TODAY...AND HAS REACHED TO ALONG ABOUT 15N 
THIS EVENING. LARGE AND VERY LONG PERIOD SWELL IS EXPECTED TO 
SPREAD ACROSS MUCH OF THE AREA S OF 24N BY SATURDAY AFTERNOON... 
INTO S PORTIONS OF THE GULF OF CALIFORNIA...AND REACH SOUTHERN 
CALIFORNIA ON SUNDAY. THESE LARGE AND POWERFUL SWELLS WILL 
GENERATE VERY LARGE SURF AND DANGEROUS MARINE CONDITIONS ALONG 
THE REGIONAL COASTS AND WITHIN THE SURFZONE THROUGH THE WEEKEND.

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STRIPLING