000
AXPZ20 KNHC 192154
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JUL 19 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...THE MONSOON 
TROUGH AXIS EXTENDS FROM 07N78W TO 10N90W TO A 1009 MB LOW PRES 
NEAR 08N95W TO 07N100W TO 12N115W TO ANOTHER 1009 MB LOW PRES 
NEAR 08N123W TO 06N126W. THE ITCZ AXIS IS FROM 06N126W TO 
05N133W TO 07N140W. SCATTERED MODERATE TO STRONG FROM 05N TO 08N 
E OF 80W AND FROM 05N TO 08N BETWEEN 85W AND 88W. SCATTERED 
MODERATE ISOLATED STRONG WITHIN 60 NM EITHER SIDE OF TROUGH AXIS 
BETWEEN 110W AND 113W...AND WITHIN 120 NM N OF TROUGH AXIS 
BETWEEN 118W AND 128W. 

...DISCUSSION...
A 1035 MB SUBTROPICAL HIGH CENTERED WELL NW OF THE FORECAST AREA 
HAS A RIDGE AXIS EXTENDING SE THROUGH 30N130W TO NEAR 20N115W. 
THE REMNANT LOW OF FABIO HAS FINALLY DISSIPATED AND WAS NO 
LONGER ANALYZED ON THE 1800 UTC SURFACE ANALYSIS. A SWIRL OF LOW 
CLOUDS WAS STILL APPARENT IN THE LAST VISIBLE IMAGES OF THE DAY. 

A PAIR OF 1009 MB LOW PRES SYSTEMS ARE EMBEDDED IN THE MONSOON 
TROUGH. THE EASTERNMOST LOW IS NEAR 08N95W WHILE THE WESTERNMOST 
IS LOCATED NEAR 08N123W. PRES GRADIENT BETWEEN THE BUILDING 
RIDGE TO THE N AND LOWER PRES ALONG THE MONSOON TROUGH IS 
RESULTING IN AN AREA OF NE WINDS 20 KT GENERALLY FROM 10N TO 14N 
BETWEEN 112W AND 122W. THESE WINDS WERE SAMPLED BY AN 1800 UTC 
ASCAT PASS. THE SAME SCATTEROMETER PASS PROVIDED OBSERVATIONS OF 
SE WINDS OF 20 KT S OF THE MONSOON TROUGH ROUGHLY FROM THE 
EQUATOR TO 04N BETWEEN 118W AND 122W. TROPICAL CYCLONE FORMATION 
IS NOT EXPECTED IN ASSOCIATION WITH THESE LOWS DURING THE NEXT 
48 HOURS. BEYOND THIS PERIOD...THE GLOBAL MODELS ARE IN GENERAL 
AGREEMENT IN DEVELOPING A LOW ALONG THE MONSOON TROUGH IN THE 
AREA BETWEEN 90W AND 95W LATE SUN AND MON WITH THE GFS THE MOST 
AGGRESSIVE IN DEVELOPING THIS LOW. 

ELSEWHERE...CROSS EQUATORIAL VERY LONG PERIOD SW SWELLS OF 20-22 
SECONDS WITH SEAS TO 8 FT EXTEND SW OF A LINE FROM NEAR THE 
GALAPAGOS ISLANDS NW TO 15N125W. THESE SWELLS WILL SPREAD ACROSS
THE FORECAST AREA OVERNIGHT AND BEGIN TO IMPACT THE COAST OF 
MEXICO...CENTRAL AMERICA AND BAJA CALIFORNIA ON FRI. THE 
POTENTIAL EXISTS FOR LARGE BREAKING WAVES AND DANGEROUS RIP 
CURRENTS ALONG THE COAST INTO THE WEEKEND AS THE SWELL TRAIN 
SLOWLY SUBSIDES. 

GAP WINDS OF 20 TO 25 KT ARE EXPECTED TO CONTINUE OVER THE GULF 
OF PAPAGAYO AS FRESH TO STRONG TRADE WIND FLOW IN THE SW 
CARIBBEAN FUNNELS THROUGH THE GAP. THE WINDS ARE GREATEST DURING 
THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE OF THE 
NOCTURNAL DRAINAGE FLOW. THIS WILL BUILD SEAS TO 9 FT ON FRIDAY. 

THE TROPICAL WAVE CURRENTLY MOVING ACROSS SE MEXICO WILL FORCE 
NLY WINDS OF 20-25 KT THROUGH THE GULF OF TEHUANTEPEC BEGINNING 
FRI AND CONTINUING INTO SAT.

$$
COBB