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000
AXPZ20 KNHC 230242
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAY 23 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 0230 UTC.


...SPECIAL FEATURES... A PAIR OF LOW PRESSURE SYSTEMS CONTINUE TO BECOME BETTER ORGANIZED THIS EVENING OVER THE DEEP TROPICS W OF 120W. THE FIRST LOW PRES AREA IS NEAR 09N125W WITH AN ESTIMATED MSLP OF 1008 MB. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS EVIDENT WITHIN 270 NM ON THE NORTHERN SEMICIRCLE OF THE LOW PRES. EARLIER SCATTEROMETER AND ALTIMETER SATELLITE DATA INDICATED 20 TO 25 KT TRADE WINDS AND SEAS TO 8 FT BETWEEN THE LOW AND A BUILDING SUBTROPICAL RIDGE TO THE NORTH...SPECIFICALLY FROM 10N TO 14N BETWEEN 120W AND 128W. THE SECOND LOW PRES IS FARTHER SOUTHWEST NEAR 05N137W WITH AN ESTIMATED MSLP OF 1008 MB. THE EASTERNMOST LOW PRES IS STARTING TO STRENGTHEN AT THE EXPENSE OF THE LOW PRES TO ITS SOUTHWEST. GLOBAL MODELS ARE IN GOOD AGREEMENT SHOWING THIS TREND...WITH THE LOW PRES NEAR 09N125W POSSIBLY DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT 48 HOURS AS IT MOVES NW. THE OTHER LOW PRES MAY ALSO FORM INTO A TROPICAL CYCLONE...BUT IT HAS A MORE LIMITED TIME FRAME TO DEVELOP...WITH INDICATIONS THAT IT WILL DISSIPATE THROUGH 48 HOURS WHILE REMAINING QUASI-STATIONARY. THE OFFICIAL FORECAST REFLECTS THESE TRENDS SHOWING A MORE DOMINANT EASTERN LOW WITH WINDS REACHING 25 TO 30 KT THROUGH 48 HOURS NEAR THE LOW CENTER AND SEAS BUILDING 12 FT.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE ITCZ AXIS WAS ANALYZED FROM 09N88W TO 07N96W TO 10N110W TO 10N120W. SCATTERED MODERATE CONVECTION WAS OBSERVED WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 88W AND 110W.


...DISCUSSION...

N OF 15N E OF 120W... A DEEP LAYER TROUGH CONTINUES TO SLOWLY MOVE EASTWARD ACROSS THE BAJA PENINSULA AND THE GULF OF CALIFORNIA...SHIFTING EAST OF THE AREA SATURDAY. RIDGING WILL BUILD WEST OF THE AREA IN THE WAKE OF THE TROUGH. THE SURFACE RIDGE WILL EXTEND FROM WEST OF THE AREA THROUGH THE REVILLAGIGEDO ISLANDS...AND WILL ALLOW FOR A SLIGHT INCREASE IN NORTHERLY FLOW ALONG THE COAST OF BAJA CALIFORNIA THROUGH SUNDAY WITH SEAS 5 TO 7 FT. FRESH WESTERLY WINDS OVER THE FAR NORTHERN GULF OF CALIFORNIA WILL DIMINISH INTO SATURDAY AS THE TROUGH SHIFTS EAST.

S OF 15N E OF 110W... AN UPPER TROUGH REMAINS ANCHORED FROM SOUTHERN MEXICO NEAR TEHUANTEPEC SOUTHWARD TO THE GALAPAGOS ISLANDS. AN EARLIER SCATTEROMETER SATELLITE PASS INDICATED FRESH GAP WINDS THROUGH THE GULF OF PAPAGAYO. A CONCURRENT ALTIMETER SATELLITE PASS INDICATED SEAS TO 7 FT IN THE GAP WIND PLUME. THIS HAS DIMINISHED BY WILL LIKELY RETURN TONIGHT...POSSIBLY WITH WINDS BRIEFLY REACHING 25 KT AND SEAS BUILDING TO 8 FT. AN UPPER RIDGE IS BUILDING WESTWARD ALONG ROUGHLY 08N-10N DISPLACING AND WEAKENING THE UPPER TROUGH. DIVERGENCE ALOFT ON THE SOUTHERN EDGE OF THE UPPER RIDGE IS ALREADY STARTING TO ENHANCE CONVECTION ALONG THE ITCZ.

LONG PERIOD SOUTH-SOUTHWESTERLY SWELL PRODUCING WAVE HEIGHTS TO 10 FT AND PERIODS OF 17-19 SECONDS WILL BEGIN TO SUBSIDE TONIGHT...WITH SEAS OVER 8 FT SLIPPING S OF THE EQUATOR BY SUN MORNING. 4 TO 6 FT OF SWELL WILL REACH THE COASTLINES OF CENTRAL AMERICA AND SOUTHERN MEXICO LATE TONIGHT AND SAT. THESE LONG PERIOD SWELLS WILL GENERATE LARGE AND DANGEROUS SURF CONDITIONS ALONG THESE COASTLINES THROUGH THE UPCOMING WEEKEND.

ELSEWHERE... A COLD FRONT APPROACHING THE HAWAIIAN ISLANDS IS EXPECTED TO TO MOVE JUST W OF THE FORECAST AREA OVER THE WEEKEND. SE WINDS WILL INCREASE AHEAD OF THE FRONT TO 20-25 KT BY SAT NIGHT WITH SEAS BUILDING TO 8-10 FT BY SUN MORNING IN THE AREA FROM 22N-29N W OF 137W. SHOWERS AND ISOLATED THUNDERSTORMS WILL ALSO MOVE IN AHEAD OF THE FRONT.

$$ CHRISTENSEN

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