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