Tropical Weather Discussion
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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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