000
AXPZ20 KNHC 092120
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU AUG 9 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 
2100 UTC.

...SPECIAL FEATURES...

TROPICAL STORM GILMA CENTERED NEAR 17.2N 119.1W AT 09/2100 UTC 
MOVING NW AT 5 KT WITH MAXIMUM SUSTAINED WINDS 60 KT GUSTS TO 75 
KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. GILMA IS EXPECTED TO 
SLOWLY WEAKEN THE NEXT 2-3 DAYS AS IT MOVES OVER INCREASINGLY
COOLER WATERS. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 
120 NM OF THE CENTER EXCEPT 75 NM NW QUADRANT.

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

DISCONTINUOUS MONSOON TROUGH EXTENDS FROM 09N78W TO 10N88W...THEN
FROM 16N96W TO 12N99W TO 10N110W...AND FROM 13N122W TO 07N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 120 NM OF
TROUGH AXIS...INCLUDING THE AREA N OF 09N BETWEEN 88W AND 96W. 

...DISCUSSION...

HIGH PRES RIDGE EXTENDS ESE FROM SUBTROPICAL HIGH CENTERED NW OF 
THE AREA NEAR 34N150W TO BAJA CALIFORNIA. TS GILMA MOVING SLOWLY 
NW IS TIGHTENING THE PRES GRADIENT N OF CENTER AS IT INTERACTS 
WITH THE RIDGE. FRESH-STRONG N WINDS ALONG THE COAST OF NORTHERN 
CALIFORNIA IS PRODUCING N SWELL TO 9 FT THAT REACHES TO 29N 
BETWEEN 120W AND 132W BASED ON SHIP REPORTS EARLIER TODAY.

A JASON ALTIMETER PASS AT 1100 UTC WAS USED TO DESCRIBE RADII FOR
8 AND 12 FT SEAS IN NE SEMICIRCLE OF GILMA AS WELL AS BASELINE OF
WAVEWATCH MODEL GUIDANCE ACROSS LARGE PORTION OF THE BASIN ALONG 
SWATH. IT INDICATES A SMALL AREA OF 8 FT SEAS IS LOCATED WELL SSE
OF GILMA NEAR 05N112W.

MODEL GUIDANCE INCLUDING GFS/ECMWF/UKMET MODELS INDICATE TROPICAL
STORM ERNESTO MAY INITIATE A SYMPATHETIC AREA OF LOW PRES IN THE 
EASTERN PACIFIC AS IT WEAKENS OVER SOUTHERN MEXICO. EXPECT WEAK 
AREA OF LOW PRES TO DEVELOP NEAR 17N102W IN ABOUT 24 HOURS WHICH 
MOVES WNW AND INTENSIFIES THROUGH THE WEEKEND. ENHANCED WSW FLOW 
S OF THE MONSOON TROUGH WILL INCREASE SEA HEIGHTS TO AROUND 7-8 
FT FROM 10N TO 12N BETWEEN 95W AND 105W BY SAT NIGHT.

$$
MUNDELL