000
AXPZ20 KNHC 290235
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC MON JUL 29 2013

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.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO LOW PRES NEAR 
09N97W 1010 MB TO 10N117W TO 12N130W TO 10N135W. THE ITCZ AXIS 
EXTENDS FROM 10N135W TO 09N140W. SCATTERED MODERATE CONVECTION 
IS WITHIN 180 NM S OF THE MONSOON TROUGH BETWEEN 86W AND 94W... 
BETWEEN 105W AND 116W...BETWEEN 118W AND 125W...AND BETWEEN 127W 
AND 130W. SIMILAR CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE 
MONSOON TROUGH BETWEEN 95W AND 104W.

...DISCUSSION...  

THE SUBTROPICAL RIDGE IS RE-ESTABLISHING ITSELF ACROSS THE 
WATERS N OF 15N W OF 110W...IN THE WAKE OF TROPICAL STORM 
FLOSSIE...NOW WELL W OF THE AREA. FOR MORE INFORMATION ON 
FLOSSIE PLEASE SEE BULLETINS UNDER AWIPS/WMO HEADERS 
HFOTCMCP1/WTPA21 PHFO WHICH CAN BE ACCESSED ONLINE AT 
WWW.WEATHER.GOV/CPHC. ANY ASSOCIATED WINDS AND SEAS ARE NOW 
COMPLETELY W OF 140W.

GALE FORCE WINDS ALONG THE COAST OF NORTHERN CALIFORNIA BETWEEN 
TROUGHING OVER INTERIOR CALIFORNIA AND THE SUBTROPICAL RIDGE 
CONTINUES TO GENERATE SEAS UP TO 8 FT REACHING S TO 31N/30N. 
THESE SEAS WILL SUBSIDE TO LESS THAN 8 FT DURING THE NEXT 24 
HOURS.

THE MAIN FORECAST ISSUE ACROSS THE EASTERN PACIFIC CONCERNS THE 
DEVELOPMENT AND MOVEMENT OF AN AREA OF 1010 MB SURFACE LOW PRES 
CURRENTLY NOTED NEAR 09N97W ALONG THE MONSOON TROUGH. ASSOCIATED 
CONVECTION IS DESCRIBED IN THE SECTION ABOVE. THE MAIN UPPER 
SUPPORT FOR THE LOW APPEARS TO BE THE DIVERGENCE BETWEEN AN 
UPPER LOW CENTERED JUST OFFSHORE OF SW CENTRAL MEXICO NEAR 
17N101W AND RIDGING ALONG THE SPINE OF CENTRAL AMERICA. EARLIER 
SCATTEROMETER DATA INDICATED FRESH TO STRONG WINDS AT THE 
SURFACE WITH THE LOW WHERE ASSOCIATED 8-10 FT SEAS ARE OCCURRING 
AS WELL. LOWER LEVEL SUPPORT IS LIKELY DUE TO THE REMNANTS OF A 
TROPICAL WAVE THAT MIGRATED INTO THE EASTERN PACIFIC A COUPLE OF 
DAYS AGO.

THE GFS MODEL REMAINS THE MOST AGGRESSIVE WITH DEVELOPING THE 
LOW WHILE THE MAJORITY OF OTHER GLOBAL MODELS REMAIN MORE 
CONSERVATIVE WITH DEVELOPMENT. A BLENDED SOLUTION WILL CONTINUE 
TO BE FOLLOWED FOR THE OFFICIAL FORECAST WITH FRESH TO STRONG 
WINDS CONTINUING TO ACCOMPANY THE LOW AS WELL AS SEAS OF 8-10 FT 
DURING THE NEXT 48 HOURS AS IT REACHES NEAR 12N106W BY 48 HOURS.
 
CROSS EQUATORIAL S TO SW SWELL RESULTING IN COMBINED SEAS OF 8-9 
FT CONTINUES TO PROPAGATE ACROSS THE DEEP TROPICS TO THE S OF 
03N BETWEEN 81W AND 88W...AND ROUGHLY S OF 09N BETWEEN 92W AND 
118W. THE AFFECTED AREA IS FORECAST TO SHIFT N COVERING THE 
WATERS NEAR THE MONSOON TROUGH MERGING WITH THE AREA AROUND 
SURFACE LOW PRES DESCRIBED ABOVE BY 24 HOURS...AS WELL AS 
BETWEEN THE WATERS E OF THE GALAPAGOS AND 81W TO 06N. BY 48 
HOURS THE CROSS-EQUATORIAL SWELL WILL SUBSIDE TO LESS THAN 8 FT.

$$ 
LEWITSKY