000
AXPZ20 KNHC 111023
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT AUG 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...SPECIAL FEATURES...

TROPICAL STORM GILMA IS AT 20.0N 119.9W AT 11/0900 UTC MOVING NNW OR 
335 DEG AT 5 KT WITH MAXIMUM SUSTAINED WINDS OF 40 KT GUSTING TO 50 
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. THE STORM IS 
EXPERIENCING E WIND SHEAR WITH ONLY A SMALL CLUSTER OF SCATTERED 
MODERATE CONVECTION DISSIPATING WELL NW OF CENTER WITHIN 30 NM OF 
21.5N121W. GILMA IS EXPECTED TO WEAKEN TO A TROPICAL DEPRESSION 
LATER TODAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS.

THE MID-LEVEL REMNANT CIRCULATION OF ATLANTIC TROPICAL CYCLONE 
ERNESTO IS NOW ANALYZED AS A SURFACE LOW PRESSURE NEAR 16.5N104W AND 
IS ESTIMATED AT 1001 MB. NUMEROUS STRONG CONVECTION HAS FLARED 
WITHIN 90 NM OF 17.5N106.5W WITH SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IN BANDS NOTED ELSEWHERE N OF 12N TO THE COAST OF MEXICO 
BETWEEN 100W AND 108W. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR 
CONTINUED DEVELOPMENT OVER THE NEXT 24 TO 48 HOURS AND TROPICAL 
CYCLONE FORMATION IS EXPECTED. 

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

A MONSOON TROUGH AXIS EXTENDS E TO W ACROSS THE EXTREME SW CARIBBEAN 
AND ACROSS SOUTHERN NICARAGUA AND COASTAL EL SALVADOR TO THE E 
PACIFIC AT 13N90W...CONTINUING WNW AND INTO THE TROPICAL LOW 
PRESSURE DEVELOPING AT 16.5N104W. THE MONSOON TROUGH AXIS THEN TURNS 
SW TO 11N110W...THEN WESTWARD TO 13N121W...THEN SW AGAIN AND 
CONTINUING BEYOND 08N140W. SCATTERED STRONG CONVECTION IS CURRENTLY 
FLARING ALONG THE COAST OF COLOMBIA AND EASTERN PANAMA...ROUGHLY 
FROM O4N TO 08N TO THE E OF 79W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS OBSERVED OVER THE TROPICAL PACIFIC AND CENTRAL AMERICA 
FROM 05N TO 19N BETWEEN 86W AND 101W. SIMILAR CONVECTION IS NOTED 
WITHIN 90 NM EITHER SIDE OF A LINE FROM 11N103W TO 08N120W...AND 
ALSO WITHIN 60 NM EITHER SIDE OF A LINE FROM 12N123W TO 08N140W.

...DISCUSSION...

AN UPPER ANTICYLONE IS CENTERED NEAR 23N131W WITH ITS ENVELOPE OF 
ANTICYCLONIC FLOW ACCOMPANIED BY VERY DRY UPPER AIR DOMINATING THE 
UPPER LEVELS FROM 20N TO 32N BETWEEN 130W AND 142W. A SECOND 
ANTICYLONE IS CENTERED OVER NW OLD MEXICO AT 28N108W...WITH A RIDGE 
EXTENDING SW TO A SHARP CREST OVER TROPICAL STORM GILMA. A SHARP 
UPPER TROUGH IS OBSERVED BETWEEN THESE TWO ANTICYCLONES EXTENDING SW 
FROM 32N114W TO 21N125W. THE DEBRIS MOISTURE FROM GILMA IS ADVECTED 
NE ALONG THE W PERIPHERY OF THE RIDGE...BUT EVAPORATES NEAR 26N118W. 
BROAD ANTICYCLONIC FLOW DOMINATES THE UPPER LEVELS FROM 10N TO 22N 
BETWEEN 90W AND 114W WHILE LOW LEVEL SOUTHWESTERLY FLOW S OF THE 
PREVIOUSLY DESCRIBED MONSOON TROUGH IS SUPPORTING THE INTENSE 
CONVECTION PREVIOUSLY MENTIONED NEAR THE REDEVELOPING REMNANTS OF 
ERNESTO AT 17.5N106.5W...AND THE OTHER CONVECTION NOTED BETWEEN 90W 
AND 100W. THE DEBRIS MOISTURE IS ADVECTED SW AND WILL SOON REACH THE 
EQUATOR BETWEEN 85W AND 115W.   

NE WINDS AT 20 KT...WITH MERGING N AND NE SWELL RESULTING IN 
COMBINED SEAS TO 9 FT...IS FORECAST OVER THE AREA N OF 25N BETWEEN 
120W AND 135W THROUGH SUN...WITH WINDS DIMINISHING TO 20 KT OR LESS 
AND SEAS SUBSIDING TO LESS THAN 8 FT ON MON.

$$
NELSON