000
AXPZ20 KNHC 090335
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...SPECIAL FEATURES...
AT 09/0000 UTC...GILMA HAS INTENSIFIED TO HURRICANE STRENGTH NEAR 
16.0N 118.1W MOVING W-NW OR 280 DEGREES AT 7 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 987 MB. MAXIMUM SUSTAINED WINDS ARE 65 KT WITH 
GUSTS TO 80 KT. THE LATEST VISIBLE AND IR SATELLITE IMAGERY SHOWS 
STRONG CONVECTION BUILDING IN THE CENTER OF GILMA...WITH NUMEROUS 
MODERATE TO STRONG CONVECTION EXTENDING TO WITHIN 90 NM OF THE 
CENTER. GILMA IS EXPECTED TO INTENSIFY SLIGHTLY THROUGH 09/1200 
UTC...THEN GRADUALLY DIMINISH THROUGH THE NEXT SEVERAL DAYS AS IT 
CONTINUES TO MOVE TO THE NW. PLEASE SEE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS.

A 1008 MB LOW PRES EMBEDDED IN THE MONSOON TROUGH IS LOCATED 
NEAR 10N103W. SCATTERED MODERATE TO STRONG CONVECTION WAS 
INDICATED WITHIN 120 NM IN THE W SEMICIRCLE OF THE LOW PRESSURE. A 
1605 UTC ASCAT PASS INDICATED ONLY A SMALL AREA OF 20 KT WINDS IN 
ASSOCIATION WITH THE LOW. HOWEVER THIS SYSTEM HAS A MEDIUM CHANCE OF 
BECOMING A TROPICAL CYCLONE AS IT DRIFTS GENERALLY WESTWARD DURING 
THE NEXT 48 HOURS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N78W TO 09N86W TO 12N93W TO A 1008 MB 
LOW NEAR 10N103W TO 10N108W. THEN CONTINUES SW OF HURRICANE GILMA 
FROM 12N123W TO 09N130W TO 09N140W. SCATTERED MODERATE CONVECTION 
FROM 04N TO 09N BETWEEN 77W AND 87W. SCATTERED MODERATE TO STRONG 
CONVECTION FROM 09N TO 12N BETWEEN 103W AND 105W. SCATTERED MODERATE 
CONVECTION FROM 07N TO 10N BETWEEN 125W AND 140W. 

...DISCUSSION...
SHARP ANTICYCLONIC FLOW ALOFT EXTENDING FROM THE SW UNITED STATES TO 
NEAR 20N120W IS PROVIDING WEAK STEERING FLOW TO GILMA AS WELL AS 
UPPER DIVERGENCE TO SUSTAINED CONVECTION ASSOCIATED WITH GILMA. 
WATER VAPOR AND PRECIPITABLE WATER IMAGERY SHOW FAIRLY DRY IN THE 
AREA GILMA IS APPROACHING...GENERALLY ACROSS W OF 120W N OF THE 
ITCZ. AN UPPER SHORT WAVE TROUGH ALONG 135W N OF 30N WILL LIFT OUT 
TO THE NE...ALLOWING THE SURFACE RIDGE N OF THE AREA TO BUILD 
SLIGHTLY. WHILE THIS WILL ALLOW A MODEST INCREASE IN TRADE WIND 
FLOW...IT WILL ALSO PROMOTE NORTHERLY SWELL TO 8 FT REACHING AS FAR 
SOUTH AS 26N BY LATE FRI. FURTHER SOUTH...BUOY AND SCATTEROMETER 
DATA SHOW SOUTHERLY WINDS OF 15 TO 20 KT S OF THE ITCZ W OF 
120W...SUPPORTING WEAK CONVECTION ALONG THE ITCZ W OF 125W. 

AN UPPER LOW IS CENTERED OVER THE CENTRAL COAST OF MEXICO NEAR 
22N103W...SUPPORTING CONVECTION NEAR THE DEVELOPING LOW PRES NEAR 
10N103W. 15 TO 20 KT SW FLOW INTO THE MONSOON TROUGH IS SUPPORTING 
CLUSTERS OF CONVECTION E OF 95W.

CROSS EQUATORIAL LONG PERIOD SW SWELLS OF 16 SECONDS CONTINUE TO 
IMPACT THE WATERS S OF 05N BETWEEN 95W AND 120W. HOWEVER AN 
ALTIMETER PASS FROM AROUND 0000 UTC CONFIRMED MWW3 OUTPUT SHOWING 
SEAS WERE GENERALLY 7 FT OR LESS AND WILL CONTINUE TO SUBSIDE.

$$
CHRISTENSEN