000
AXPZ20 KNHC 131544
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON AUG 13 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...SPECIAL FEATURE...

THE CENTER OF MINIMAL TROPICAL STORM HECTOR IS NEAR 18.1N 112.2W 
AT 1500 UTC. IT WAS MOVING W OR 270 DEG AT 06 KT AND HAD MAXIMUM 
SUSTAINED WINDS OF 35 KT WITH GUSTS TO 45 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE WAS 994 MB. HECTOR CONTINUES TO LIE UNDER 
STRONG EASTERLY SHEAR WITH NUMEROUS STRONG CONVECTION SKEWED 
BETWEEN 60 NM AND 300 NM W QUADRANT OF THE CENTER. THE INTENSITY 
OF HECTOR IS EXPECTED TO CHANGE LITTLE THROUGH TUE EVENING AS IT 
STEERED WESTWARD ON THE SOUTH SIDE OF THE MID-LEVEL RIDGE 
CENTERED OVER THE SW UNITED STATES. HECTOR IS EXPECTED TO WEAKEN 
TO A DEPRESSION ON WED. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS.

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

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 09N82W TO 09N90W TO 
LOW PRES NEAR 14.5N98W THEN CONTINUES FROM 14N113W TO 14N128W TO 
09N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS 
WITHIN 120 NM N SEMICIRCLE OF THE LOW PRES SYSTEM. SCATTERED 
MODERATE CONVECTION WAS WITHIN 300 NM SW OF THE AXIS BETWEEN 83W 
AND 92W. 

...DISCUSSION...

RIDGING ALOFT EXTENDS OVER MUCH OF THE AREA N OF 15N AND W OF 
120W...STEMMING FROM AN ANTICYCLONE NEAR 24N129W THAT EXTENDS A 
RIDGE ALONG 24W BETWEEN 111W AND 140W. WATER VAPOR IMAGERY 
INDICATES STRONG SUBSIDENCE UNDER THIS RIDGE N OF 10N W OF 135W 
AND N OF 25N W OF 120W. SCATTERED MODERATE CONVECTION LIES UNDER 
THE RIDGE AXIS OVER THE GULF OF CALIFORNIA FROM 22N TO 26N. 
UPPER DIFFLUENCE NEAR THE RIDGE AXIS IS ENHANCING THIS 
CONVECTION. UPPER LOW LIE BOTH N AND S OF THE RIDGE 
AXIS NEAR 31N116W AND 21N108W...RESPECTIVELY. E-NE WINDS ALOFT 
BETWEEN THE RIDGE AND THE SOUTHERN LOW ARE PASSING OVER TROPICAL 
STORM HECTOR AND FORCING THE DEEP CONVECTION W OF THE CENTER. 
PLEASE SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS ABOUT 
HECTOR.

A SECOND ANTICYCLONE ALOFT IS NEAR 18N97W AND EXTENDS A RIDGE TO 
13N103W. AN AREA OF LOW PRES EMBEDDED IN THE MONSOON TROUGH LIES 
UNDER THIS RIDGE. DEEP CONVECTION NEAR THIS LOW HAS BECOME MORE 
ORGANIZED OVER THE PAST 24 HOURS. HOWEVER...THE LOW WILL SOON 
ENCOUNTER INCREASED SHEAR AND CONFIDENCE IS LOW THAT THE SYSTEM 
WILL SHOW MORE THAN SLOW DEVELOPMENT OVER THE NEXT FEW DAYS. 
CONVECTION NEAR THIS LOW IS DESCRIBED IN THE SECTION ABOVE. 

SCATTERED MODERATE CONVECTION WAS FOUND WITHIN THE BREAK IN THE 
MONSOON TROUGH FROM 09N TO 14N BETWEEN 102W AND 122W...WHERE 
SPEED DIFFLUENCE IN THE REAR RIGHT QUADRANT OF A 40-50 KT 
EAST-NORTHEASTERLY UPPER JET ALONG THE EQUATOR W OF 110W IS 
LIFTING THE LOW LEVEL MOSITURE POOLED ALONG 11N AND ENHANCING 
CONVECTION.

THE CENTER OF THE ELONGATED 1026 MB SUBTROPICAL HIGH WAS 
ANALYZED NW OF THE FORECAST AREA NEAR 38N140W. THE HIGH IS 
FORECAST TO MIGRATE NW OVER THE NEXT FEW DAYS...PREVENTING THE 
RETURN OF TRADE WINDS STRONGER THAN A MODERATE BREEZE TO THE 
AREA.  

THE REMNANTS OF GILMA WERE ANALYZED NEAR 22N122W AT 1010 MB. THE 
0512 UTC ASCAT PASS SHOWED WINDS HAVE DIMINISHED BELOW 20 KT IN 
THE W SEMICIRCLE. THE CIRCULATION IS EXPECTED TO OPEN INTO A 
TROUGH OVER THE NEXT 24 HOURS.

THE LEADING EDGE OF CROSS-EQUATORIAL SWELL WILL PROPAGATE N OF 
THE EQUATOR LATER TODAY WITH PERIODS IN THE 19-21 SECOND RANGE. 
THIS SWELL WILL BRING SEAS IN THE 8-10 FT RANGE TO WATERS S OF 
03N E OF 110W TUE MORNING AND MOVE NORTHWARD THROUGH WED. THE 
LEADING EDGE OF THE SWELL WILL REACH THE ENTIRE COASTLINE SOUTH 
OF MANZANILLO MEXICO BY WED MORNING. 

GAP WINDS...FRESH TO STRONG NE TO E WINDS ARE EXPECTED TO 
CONTINUE TO SURGE INTO AND JUST DOWNSTREAM OF THE GULF OF 
PAPAGAYO THROUGH MIDDAY TUE BEFORE DIMINISHING.

$$
SCHAUER