000
AXPZ20 KNHC 091605
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU AUG 09 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 
1500 UTC.

...SPECIAL FEATURES...

HURRICANE GILMA CENTERED NEAR 16.9N 118.9W AT 09/1500 UTC OR ABOUT 
715 MILES SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MOVING NW AT 6 
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 989 MB. MAXIMUM SUSTAINED 
WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/TPZ22 KNHC FOR 
MORE DETAILS. GILMA IS A CATEGORY ONE HURRICANE AND IT IS FORECAST 
TO WEAKEN TO A TROPICAL STORM AT ANY TIME TODAY OR TONIGHT WITH 
ACCELERATED WEAKENING FORECAST TO BEGIN FRIDAY. THIS WEAKENING WILL 
OCCUR WHEN GILMA BEGINS TO MOVE OVER COOLER SSTS. IN ADDITION THE 
CENTER IS SLIGHTLY TILTED TO THE SE WITH HEIGHT. SCATTERED STRONG 
CONVECTION IS WITHIN 90 NM IN THE NE AND SE QUADRANTS AND 120 NM IN 
THE E QUADRANT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 180 NM IN THE SW AND 90W IN THE NW QUADRANTS.

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

THE MONSOON TROUGH EXTENDS FROM 09N84W TO 14N95W WHERE IT ENDS. IT 
THEN RESUMES AT 13N99W TO A 1010 MB LOW NEAR 12N106W TO 11N114W 
...WHERE IT ENDS. IT BEGINS AGAIN AT 13N122W TO 09N131W WHERE IT 
TRANSITIONS TO THE ITCZ TO 08N140W. SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION IS WITHIN 120 NM S OF THE MONSOON TROUGH BETWEEN 
84W AND 91W...AND ALSO ALONG AND WITHIN 120 NM N OF THE ITCZ. IN 
ADDITION...SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 210 NM IN THE SE SEMICIRCLE OF THE LOW.

...DISCUSSION...

AN UPPER LEVEL TROUGH IS OVER THE FAR NW PORTION OF THE DISCUSSION 
WATERS BEING BLOCKED BY AN UPPER RIDGE WHICH EXTENDS FROM AN 
ANTICYCLONE CENTERED OVER CENTRAL ARIZONA...WITH THE RIDGE REACHING 
SW ACROSS THE FAR NORTHERN BAJA CALIFORNIA PENINSULA TO 24N123W TO 
13N130W. MAINLY DRY AIR EXISTS ACROSS THE WATERS N OF 14N W OF 120W. 
GILMA IS FORECAST TO MAINTAIN A SLOW NW MOTION FOR THE NEXT FEW DAYS 
AS IT MOVES INTO A WEAKNESS IN THIS RIDGE. ELSEWHERE ALOFT...MAINLY 
UPPER LEVEL EASTERLY FLOW COVERS THE REMAINDER OF THE DISCUSSION 
AREA.

1026 MB SURFACE HIGH PRES IS NW OF THE AREA NEAR 34N150W WITH A 
RIDGE EXTENDING E-SE OF THE HIGH INTO THE DISCUSSION WATERS NEAR 
32N140W WITH A TERMINUS NEAR 23N116W N OF GILMA. A TIGHT PRES 
GRADIENT EXISTS OVER THE N CENTRAL WATERS BETWEEN THIS RIDGE AND 
TROUGHING OVER INTERIOR CALIFORNIA AND THE BAJA CALIFORNIA 
PENINSULA. THIS GRADIENT IS RESULTING IN FRESH NORTHERLY WINDS N OF 
27N BETWEEN 120W AND 132W ALONG WITH SEAS TO 9 FT IN NORTHERLY 
SWELL. THESE CONDITIONS WILL PERSIST THROUGH THE NEXT 24-48 HOURS 
GRADUALLY SHIFTING TO COVER THE WATERS N OF 26N BETWEEN 124W AND 
137W BY SAT MORNING. 

AN AREA OF NUMEROUS STRONG CONVECTION EXISTS N OF 10N BETWEEN 91W 
AND 99W INCLUDING THE GULF OF TEHUANTEPEC RELATED TO TROPICAL STORM 
ERNESTO WHICH IS SCRAPING ACROSS THE FAR SW GULF OF MEXICO AND BAY 
OF CAMPECHE. A NEW AREA OF LOW PRES IS FORECAST TO DEVELOP NEAR 
15N105W BY FRI EVENING WITH PERHAPS SOME OF THE VORTICITY AND ENERGY 
ASSOCIATED WITH ERNESTO HELPING TO DEVELOP THIS NEW LOW. ONCE THE 
LOW FORMS...FRESH TO STRONG WINDS WILL OCCUR NEAR THE LOW FRI 
EVENING THROUGH SAT MORNING AS IT SLOWLY MOVES W.

$$
LEWITSKY