000 AXPZ20 KNHC 082201 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED AUG 08 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 2145 UTC. ...SPECIAL FEATURES... TROPICAL STORM GILMA IS AT THE THRESHOLD OF HURRICANE STRENGTH. AT 08/2100 UTC...GILMA WAS CENTERED NEAR 16.1N 117.8W MOVING W-NW OR 285 DEGREES AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 989 MB. MAXIMUM SUSTAINED WINDS REMAIN 60 KT WITH GUSTS TO 75 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. THE LATEST VISIBLE SATELLITE IMAGERY SHOWS A GRADUAL INCREASE IN THE ORGANIZATION OF THE CYCLONE WITH INCREASED BANDING AROUND THE CYCLONE CENTER. CURRENTLY NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED WITHIN 45-60 NM OF THE CENTER WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION ELSEWHERE WITHIN 120 NM IN THE SW SEMICIRCLE. GILMA IS EXPECTED TO BECOME A HURRICANE TONIGHT AS IT CONTINUES TO BECOME BETTER ORGANIZED OVER WARM WATERS AND IN A LOW SHEAR ENVIRONMENT. A 1008 MB LOW PRES EMBEDDED IN THE MONSOON TROUGH IS LOCATED NEAR 11N104W. SCATTERED MODERATE TO STRONG CONVECTION WAS INDICATED WITHIN 60-75 NM IN THE W SEMICIRCLE OF THE LOW PRESSURE. A 1605 UTC ASCAT PASS INDICATED 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 9N83W TO 12N96W TO 1008 MB LOW NEAR 11N104W TO 13N109W. THEN CONTINUES SW OF T.S. GILMA FROM 12N120W TO 09N130W. ITCZ AXIS EXTENDS FROM 09N130W TO BEYOND 09N140W. SCATTERED MODERATE FROM 05N TO 10N BETWEEN 77W AND 90W... FROM 09N TO 13N BETWEEN 103W AND 106W...AND FROM 11N TO 15N BETWEEN 113W AND 117W. ...DISCUSSION... ALOFT...A BROAD ANTICYCLONE OVER ARIZONA AND THE FOUR CORNERS OF THE SW CONUS EXTENDS A RIDGE SOUTHWESTWARD ACROSS BAJA CALIFORNIA THROUGH 27N130W TO 24N140W...GENERALLY TO THE NORTH OF T.S. GILMA. UPPER DIFFLUENCE BETWEEN THE RIDGE AND A SMALL UPPER LEVEL LOW ABOUT 360 NM W OF T.S. GILMA NEAR 22N130W IS HELPING TO SUSTAIN THE DEEP CONVECTION ASSOCIATED WITH GILMA AND PROVIDING EXCELLENT OUTFLOW OVER THE CYCLONE. STRONG W TO SW FLOW AHEAD OF A LONG WAVE TROUGH IS AFFECTING THE NW CORNER OF THE AREA. THESE WINDS ARE TRANSPORTING ABUNDANT MID/UPPER LEVEL MOSITURE. NE WINDS ALOFT ARE MAINLY S OF 12N AND E OF 110W. THESE WINDS ARE ENHANCING THE CONVECTION NEAR THE MONSOON TROUGH. AT THE SURFACE...COMPLEX HIGH PRES LOCATED NEAR 35N143W EXTENDS A RIDGE OVER THE NORTHERN WATERS TO NEAR 24N115W. THE HIGH PRESSURE IS FORECAST TO MOVE NE AND SLIGHTLY INTENSIFY. PRESSURE GRADIENT BETWEEN THE HIGH AND THE ITCZ HAS RESULTED IN AN AREA OF 20 KT TRADE WINDS FROM 11N TO 15N W OF 135W PER A 1426 UTC ASCAT PASS. AS THE HIGH PRES MOVES NE...EXPECT THE AREA OF TRADES TO GRADUALLY MOVE W OF THE DISCUSSION AREA BY THU. AT THE SAME TIME...THE PRESSURE GRADIENT WILL TIGHTEN NEAR THE COAST OF CALIFORNIA AND JUST N OF THE FORECAST REGION RESULTING IN NLY WINDS OF 20 KT OVER THE N WATERS MAINLY N OF 27N AND W OF 120W. SEAS OF AROUND 8 FT GENERATED BY THESE WINDS WILL REACH 30N THU NIGHT. CROSS EQUATORIAL LONG PERIOD SW SWELLS OF 17-18 SECONDS ARE NOW IMPACTING THE SOUTH-CENTRAL WATERS RAISING SEAS TO 8 FT MAINLY S OF 06N BETWEEN 115W AND 126W. THIS SWELL EVENT WILL CONTINUE TO PROPAGATE NWD OVER THE NEXT COUPLE OF DAYS...BUT SEAS WILL SUBSIDE TO LESS THAN 8 FT IN ABOUT 24 HOURS. GAP WINDS...WINDS IN THE OUTER CIRCULATION OF T.S ERNESTO... CURRENTLY OVER THE SOUTHERN YUCATAN PENINSULA HAVE VEERED TO THE WEST AND NORTHWEST IN THE VICINITY OF THE CHIVELA PASS AND HAVE THEREFORE CUT OFF THE GAP WIND FLOW INTO THE GULF OF TEHUANTEPEC. $$ COBB