000
AXPZ20 KNHC 012225
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC FRI MAY 01 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC. 

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

THE MONSOON TROUGH EXTENDS FROM 08.5N92W TO LOW PRES 1008 MB  
NEAR 06N102.5W TO 09N111W TO 06.5N140W. SCATTERED TO LOCALLY 
NUMEROUS MODERATE TO STRONG CONVECTION NOTED FROM 02N TO 11N E 
OF 87W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 180 
NM N AND 270 NM S OF TROUGH W OF 100W. 

...DISCUSSION...    

ZONAL FLOW ALOFT CONTINUES ACROSS MOST OF THE AREA N OF 15N THIS 
AFTERNOON...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 1034 MB HIGH NEAR 40N147W...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 N GAP WIND EVENT IN THE GULF OF TEHUANTEPEC. 

ACTIVE CONVECTION CONTINUES ACROSS THE AREA E OF 90W...AND NEAR 
THE MONSOON TROUGH W OF 100W...AS DESCRIBED ABOVE. ACTIVE 
CONVECTION IS EXPECTED TO CONTINUE E OF 110W THROUGH TONIGHT AND 
THEN GRADUALLY DIMINISH OVER THE WEEKEND.

ACROSS THE GULF OF TEHUANTEPEC...STRONG NORTHERLY WINDS HAVE 
DIMINISHED TO NEAR 20 KT THIS AFTERNOON...WHILE SEAS DOWNWIND TO 
12N REMAIN AROUND 8 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 SATURDAY NIGHT...BEFORE DIMINISHING LESS THAN 20 
KT SUNDAY AFTERNOON THROUGH MON.
 
LARGE SW SOUTHERN HEMISPHERIC SWELL HAS BEGUN TO MOVE INTO THE 
DISCUSSION AREA TODAY...WITH MORNING ALTIMETER READINGS SHOWING 
SEAS AS HIGH AS 12 FT ALONG THE EQUATOR AT 112W. A FIRST 
MODERATE INITIAL PULSE OF SWELL HAS REACHED THE COASTLINES OF 
CENTRAL AMERICA AND MEXICO TODAY...WITH LARGE AND VERY LONG 
PERIOD SWELL EXPECTED TO SPREAD ACROSS MUCH OF THE AREA S OF 24N 
BY SATURDAY AFTERNOON...AND INTO S PORTIONS OF THE GULF OF 
CALIFORNIA...REACHING SOUTHERN CALIFORNIA SUNDAY. THESE LARGE 
AND POWERFUL SWELLS WILL GENERATE VERY LARGE SURF AND DANGEROUS 
CONDITIONS ALONG THE REGIONAL COASTS THROUGH THE WEEKEND.

$$
STRIPLING