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000
AXPZ20 KNHC 240238
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN MAY 24 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 0300 UTC.


...SPECIAL FEATURES...

BROAD CYCLONIC CIRCULATION IS ANALYZED AS A 1008 MB SURFACE LOW NEAR 11N129W. SCATTERED MODERATE CONVECTION WAS WITHIN 90 NM NE SEMICIRCLE OF THIS LOW. THE PRESSURE GRADIENT BETWEEN THIS LOW THE SUBTROPICAL RIDGE TO THE N IS MAINTAINING NE TO E 20 TO 25 KT WINDS WITHIN 240 NM NW QUADRANT OF THE LOW. AN EARLIER ALTIMETER SATELLITE PASS INDICATED SEAS TO 9 FT AS WELL. THE LOW HAS THE POTENTIAL TO BECOME A TROPICAL CYCLONE AS IT MOVES N-NW TO NEAR 12N132W SUN AND NEAR 14N135W MON.

A 1008 MB LOW IS ANALYZED AT 05N139W WITH SCATTERED MODERATE TO STRONG CONVECTION OBSERVED WITHIN 75 NM SE SEMICIRCLE WHERE WINDS ARE BELIEVED TO BE A FRESH TO OCCASIONALLY STRONG BREEZE BASED ON AN EARLIER SCATTEROMETER SATELLITE PASS. THERE IS SOME POTENTIAL FOR TROPICAL CYCLONE FORMATION AS THE LOW REACHES NEAR 06N139W SUN AND NEAR 08N140W MON. BY TUE...NUMERICAL GUIDANCE SUGGESTS THIS LOW WILL WEAKEN AS THE LOW PRESSURE SYSTEM TO ITS EAST INTENSIFIES.


...TROPICAL WAVES...

A TROPICAL WAVE WAS ANALYZED NEAR 95W FROM THE GUATEMALA COAST TO NEAR THE GALAPAGOS ISLANDS. SCATTERED MODERATE TO STRONG CONVECTION WAS OBSERVED NEAR THE AXIS FROM 04N TO 09N BETWEEN 87W AND 97W. THIS WAVE IS FORECAST TO CONTINUE W AROUND 10-15 KT OVER THE NEXT FEW DAYS.


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

THE ITCZ WAS ANALYZED FROM 06N100W TO 09N110W...AND 08N115W TO 10N125W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WAS WITHIN 210 NM N OF THE AXIS BETWEEN 110W AND 120W.


...DISCUSSION...

N OF 15N E OF 120W...1030 MB HIGH PRESSURE CENTERED WELL N OF THE AREA NEAR 44N135W EXTENDS A RIDGE AXIS THROUGH 30N135W TO THE ISLAS REVILLAGIGEDO. THIS RIDGE IS EXPECTED TO REMAIN QUASISTATIONARY TO EARLY NEXT WEEK. ON THE EASTERN SIDE OF THE RIDGE...RECENT SHIP OBSERVATIONS AND EARLIER SCATTEROMETER DATA INDICATED MODERATE TO FRESH NW WINDS ALONG THE BAJA COAST BETWEEN CABO SAN LAZARO AND PUNTA EUGENIA. THE GFS INDICATES THIS MAY PULSE TO 25 KT OVERNIGHT...REPEATING A TREND FROM LAST NIGHT. AN EARLIER ALTIMETER PASS NOTED SEAS TO 7 FT...LIKELY SUPPORTED BY SW SWELL IN ADDITION TO SHORTER PERIOD NW WIND FLOW. THESE COMBINED SEAS WILL INCREASE SLIGHTLY TONIGHT AS WINDS PULSE HIGHER ALONG THE COAST. THE PRESSURE GRADIENT WILL WEAKEN SUN AS DEEP LAYERED LOW PRESSURE OVER THE SW UNITED STATES SHIFTS EASTWARD. THIS WILL DIMINISH THE WINDS. MEANWHILE A FEW THUNDERSTORMS WERE NOTED EARLIER OVER SOUTHERN BAJA PENINSULA AND ADJACENT WATERS INCLUDING THE SOUTHERN GULF OF CALIFORNIA RELATED TO JET DYNAMICS ALOFT AHEAD OF AN APPROACHING UPPER TROUGH. 4-6 FT SEAS IN SOUTH-SOUTHWESTERLY SWELL OF 17-19 SECOND PERIOD HAS REACHED THE ENTIRE PACIFIC COAST S OF CABO LAZARO IN BAJA CALIFORNIA SUR. THESE LONG PERIOD SWELLS WILL SUBSIDE OVER THE NEXT TWO DAYS...BUT WILL STILL GENERATE LARGE AND DANGEROUS SURF CONDITIONS ALONG THE COASTLINE THROUGH THE WEEKEND.

S OF 15N E OF 110W...THE PRESSURE GRADIENT BETWEEN RIDGING OVER THE NW CARIBBEAN AND TROUGHING TO THE SW ENHANCED BY THE AFOREMENTIONED TROPICAL WAVE HAS GENERATED 20-25 KT WINDS IN THE GULF OF PAPAGAYO THIS MORNING WITH THE HELP OF NOCTURNAL DRAINAGE FLOW. SEAS HAVE BUILT TO 8 FT. ENHANCED SEAS WILL PROPAGATE W AND MIX WITH LONG PERIOD CROSS-EQUATORIAL SW SWELL ACROSS THE PACIFIC WATERS FROM 09-12N BETWEEN 90-96W THIS EVENING AND SUBSIDE TO 5-7 FT TONIGHT. ANOTHER WEAKER PULSE OF FRESH TO STRONG WINDS IS EXPECTED IN THE GULF OF PAPAGAYO SUN NIGHT DURING THE PERIOD OF PEAK NOCTURNAL DRAINAGE FLOW.

ELSEWHERE...ASIDE FROM THE TWO LOW PRESSURE SYSTEM MENTIONED ABOVE...PRIMARILY MODERATE TO FRESH TRADE WINDS LIE SW OF THE RIDGE AXIS. AN EARLIER RAPIDSCAT SATELLITE PASS INDICATED FRESH SW FLOW ON THE SW SIDE OF THE RIDGE NEAR 23N135W...BETWEEN THE RIDGE...PART OF A CONFLUENT AREA OF WINDS FLOWING INTO A WELL DEVELOPED LOW PRES AREA NEAR 33N150W. A COLD FRONT ASSOCIATED WITH THE LOW PRES WILL APPROACH THE WATERS ALONG 140W BETWEEN 20N AND 30N BY EARLY SUN BEFORE STALLING AND DISSIPATING MON AS THE SUPPORTING LOW PRES LIFTS NE OF THE AREA. THE MAIN MARINE IMPACT WILL BE CONTINUED FRESH SW FLOW WITH SEAS TO 9 FT IN THE AREA N OF 25N W OF 135W THROUGH SUNDAY.

$$ CHRISTENSEN

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