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000
AXPZ20 KNHC 040245
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAY 04 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 08N76.5W TO 04N95W TO 09N111W TO LOW PRES 1008 MB NEAR 08N116.5W TO 08.5N122W...WHERE IT TERMINATES. ITCZ EXTENDS FROM 06N128W TO BEYOND 06.5N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED N OF 02.5N E OF 83.5W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM N AND 360 NM S OF TROUGH BETWEEN 84W AND 100W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 180 NM SE AND 330 NM NW QUADRANT OF LOW PRES NEAR 08N116.5W.


...DISCUSSION...

AN UPPER LEVEL BLOCKING PATTERN HAS DEVELOPED ACROSS THE BROAD REGION...WITH A BROAD UPPER RIDGE ACROSS THE TROPICAL NE PACIFIC S OF 30N AND CENTERED ALONG ABOUT 110-111W...WITH A BROAD UPPER TROUGH ACROSS THE GULF OF MEXICO AND INTO THE NW CARIBBEAN ALONG 83-85W...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 30N127W TO 25N131W...WHILE AN UPSTREAM SHORTWAVE TROUGH IS ALONG 144W 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. 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 ACROSS W PORTIONS...ANCHORED ON A 1026 MB HIGH NEAR 35N146W AND EXTENDS SE TO NEAR 21N110W. 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 THIS 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. SUNDAY 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 LATE MON NIGHT. SIGNIFICANT SWELL IS ALSO ENTERING THE SOUTHERN SECTIONS OF THE GULF OF CALIFORNIA...WERE SEAS ARE EXPECTED TO BUILD TO 7 TO 10 FEET OVERNIGHT.

$$ STRIPLING

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