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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 032221
TWDEP 

TROPICAL WEATHER DISCUSSION                                 
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC SUN MAY 03 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 
2100 UTC. 

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

THE MONSOON TROUGH EXTENDS FROM 08N76.5W TO 06.5N90W TO 07N107W 
TO 09N111W TO LOW PRES 1010 MB NEAR 07.5N116.5W...WHERE IT 
TERMINATES. ITCZ EXTENDS FROM 06N130W TO BEYOND 07N140W. 
SCATTERED TO NUMEROUS MODERATE TO STRONG CONVECTION NOTED N OF 
02N E OF 83.5W. SCATTERED MODERATE TO STRONG WITHIN 90 NM N AND 
360 NM S OF TROUGH BETWEEN 85W AND 99W. SCATTERED MODERATE TO 
STRONG WITHIN 270 NM W SEMICIRCLE OF LOW NEAR 07.5N116.5W. 

...DISCUSSION...    

AN UPPER LEVEL BLOCKING PATTERN HAS DEVELOPED ACROSS THE 
REGION...WITH A BROAD UPPER RIDGE ACROSS THE TROPICAL NE PACIFIC 
S OF 30N AND ALONG ABOUT 111W...WITH A BROAD UPPER TROUGH ACROSS 
THE GULF OF MEXICO AND INTO THE NW CARIBBEAN ALONG 83W...AND A 
DOWNSTREAM BROAD UPPER RIDGE ACROSS THE TROPICAL ATLANTIC ALONG 
50W. A MIDDLE TO UPPER LEVEL TROUGH AXIS PREVAILS ACROSS NW 
PORTIONS OF THE DISCUSSION AREA...WITH SEVERAL SMALL EMBEDDED 
CYCLONES ALONG THE AXIS...AND PASSES THROUGH 30N128W TO 
26N131W...WHILE AN UPSTREAM SHORTWAVE TROUGH IS ALONG 146W AND N 
OF 25N AND IS PROGRESSING EASTWARD. THESE TWO TROUGHS ARE 
FORECAST TO SHIFT ENE OVER THE RIDGE AND INTO THE WESTERN U.S. 
THROUGH THU...AND WILL ACT TO FLATTEN THE UPPER RIDGE BY THU. 
UPPER LEVEL CONDITIONS ASSOCIATED WITH THE RIDGE ARE EXPECTED TO 
MAINTAIN CONDITIONS FAVORABLE FOR CONTINUED ACTIVE CONVECTION 
ACROSS THE TROPICS E OF 100W...AND IN THE VICINITY OF 120W... 
THROUGH MON MORNING BEFORE CONVECTION DIMINISHES.

AT THE SURFACE...A WEAKENING HIGH PRESSURE RIDGE CONTINUES TO 
PREVAIL ACROSS W PORTIONS...ANCHORED ON A 1027 MB HIGH NEAR 
35N147W AND EXTENDS SE TO NEAR 23N120W. THE PRESSURE GRADIENT 
BETWEEN THE HIGH AND THE ITCZ TO THE S IS SUFFICIENT TO PROMOTE 
MODERATE TO FRESH NE TRADEWINDS S OF 26N AND W OF 132W. THE HIGH 
IS EXPECTED TO REMAIN GENERALLY STATIONARY AND STRENGTHEN 
SLIGHTLY THROUGH WED BEFORE SHIFTING SE AND WEAKENING AHEAD OF 
AN APPROACHING COLD FRONT. NW WINDS ACROSS THE W COASTAL WATERS 
OF BAJA CALIFORNIA ARE EXPECTED TO INCREASE TO 15-20 KT MON 
NIGHT THROUGH MID WEEK AS THE HIGH PRES BUILDS TO THE COAST. 
ELSEWHERE...WINDS REMAIN LIGHT TO MODERATE ACROSS THE REMAINDER 
OF THE AREA.

LARGE SW SOUTHERN HEMISPHERIC SWELL CONTINUES TO MOVE N AND NE 
ACROSS MUCH OF THE AREA THIS EVENING...AND HAS PEAKED IN SIZE 
TODAY. MORNING AND AFTERNOON ALTIMETER PASSES MEASURED WAVE 
HEIGHTS OF 10 TO 14 FT ACROSS THE WATERS E OF 100W...DOMINATED 
BY THIS LONG PERIOD SW SWELL. LARGE AND DANGEROUS SURF ALONG THE 
PACIFIC COASTLINES FROM PERU TO COLOMBIA TO MEXICO WILL 
GRADUALLY BEGIN TO SUBSIDE TONIGHT AND THEN MORE QUICKLY ON 
MONDAY BEFORE THIS CURRENT SWELL EVENT ENDS MON NIGHT. 
SIGNIFICANT SWELL IS ALSO ENTER THE SOUTHERN SECTIONS OF THE 
GULF OF CALIFORNIA...WERE SEAS ARE EXPECTED TO BUILD TO 7 TO 10 
FEET THIS EVENING. 

$$
STRIPLING


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Page last modified: Sunday, 03-May-2015 22:21:43 UTC