000 AXPZ20 KNHC 131602 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU AUG 13 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1530 UTC. ...SPECIAL FEATURES... AT 1500 UTC...TROPICAL STORM GUILLERMO WAS NEAR 17.1 121.6W...OR ABOUT 860 NM W-SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA... MOVING TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 12 KT. MAXIMUM SUSTAINED WINDS HAD INCREASED TO NEAR 55 KT WITH GUSTS TO 65 KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 994 MB. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. DEEP CONVECTION ASSOCIATED WITH GUILLERMO HAS BECOME MOST CONCENTRATED ACROSS THE S SEMICIRCLE...AND HAS DIMINISHED A BIT ACROSS THE N HALF...EXCEPT IN A SHORT OUTER BAND IN THE NW QUADRANT. ALSO ANTICYCLONIC OUTFLOW IN THE UPPER LEVELS IS NOT QUITE AS IMPRESSIVE AS THE OVERNIGHT HOURS...BUT REMAINS FAVORABLE. AN INTERMITTENT EYE IS SUGGESTED BY RECENT IMAGERY...AND WITH THE IMPROVED BANDING ON THE S SIDE OF GUILLERMO...THE SYSTEM MAY BE APPROACHING HURRICANE STRENGTH. THIS INTENSIFICATION IS FORECAST DURING THE NEXT 12 TO 24 HOURS...AS IT CONTINUES TO MOVE WEST-NORTHWESTWARD. ...TROPICAL WAVES... A TROPICAL WAVE WAS ANALYZED ALONG 79/80W MOVING W NEAR 15 KT. LONG TERM SATELLITE LOOPS...SUNY ALBANY GFS DIAGNOSTICS AND TPW ANIMATIONS SUGGEST THAT THIS WAVE MAY BE MORE POSITIVELY TILTED...WITH THE N PORTION EXTENDING NW INTO COASTAL NICARAGUA....WHERE SCATTERED MODERATE CONVECTION HAS RECENTLY FLARED. ELSEWHERE IN THE VICINITY OF THE WAVE...ISOLATED TO SCATTERED CONVECTION WAS OCCURRING S OF 10N. A TROPICAL WAVE WAS ANALYZED ALONG 91/92W MOVING W NEAR 15 KT...LIKELY BASED ON EXTRAPOLATION. HOWEVER...SUNY ALBANY GFS DIAGNOSTICS AND TPW ANIMATIONS SUGGEST THAT THIS WAVE MAY BE FARTHER WEST...CLOSER TO 99/100W. THIS ILLUSTRATES THE DIFFICULTLY IN TRACKING THESE TROPICAL WAVES AFTER THEY PASS 70W. ISOLATED DEEP CONVECTION WAS OCCURRING NEAR THE ITCZ ASSOCIATED WITH THE ANALYZED LOCATION ALONG 91/92W...WHILE WIDESPREAD DEEP CONVECTION WAS OCCURRING W OF 98W FROM THE ITCZ N TO NEAR THE MEXICAN COASTLINE ASSOCIATED WITH BROAD MOISTURE CONVERGENCE AND SYNOPTIC SCALE LIFT IN THE SE QUADRANT OF A BROAD UPPER LOW. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG THE LINE...08N81W TO 07N90W TO 08N106W TO 52N115W TO 14N124W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 60 NM OF AXIS FROM 81W TO 95W AND WITHIN 120 NM SOUTH OF AXIS FROM 115W TO 122W. SCATTERED MODERATE ISOLATED STRONG FROM 06N TO 15N FROM 98W TO 105W. ...DISCUSSION... AN UPPER LEVEL LOW IS CENTERED OVER THE MEXICAN COAST NW OF ACAPULCO NEAR 18N103W. AN ASSOCIATED TROUGH COVERS THE AREA FROM 95W TO 112W NORTH OF THE ITCZ AND EXTENDS OVER MUCH OF CENTRAL AND NORTHERN MEXICO. DIVERGENCE ALOFT ON THE SE SIDE OF THE TROUGH IS ENHANCING CONVECTION WITHIN AND NORTH OF THE ITCZ FROM 06N TO 16N BETWEEN 98W AND 105W. TPW ANIMATIONS SHOW A LARGE AND BROAD AREA OF ABUNDANT MOISTURE CONVERGING ACROSS THIS ZONE AS THE LOW LEVEL ELY FLOW ENCOUNTERS THE CIRCULATION OF THE UPPER TROUGH. AN UPPER TROUGH IS NW OF A LINE THROUGH 32N116W TO THE ITCZ NEAR 133W. THIS AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS DUE TO CONVERGENCE AND SINKING AIR...WITH OVERCAST STRATOCUMULUS IN THE LOWER LEVELS NORTH OF 20N EAST OF 135W AND SCATTERED TO BROKEN STRATOCUMULUS ELSEWHERE. BETWEEN THE TWO TROUGHS BROAD ANTICYCLONIC FLOW IS NOTED. THIS INCLUDES THE DIFFLUENT ANTICYCLONIC FLOW OVER GUILLERMO. THIS AREA IS MOIST ALOFT WITH BROKEN TO OVERCAST HIGH CLOUDS ASSOCIATED WITH GUILLERMO SOUTH OF 25N AND WEST OF 117W. WEAK SURFACE RIDGE IS NORTH OF 22N WEST OF 115W. ELSEWHERE EXCEPT FOR GUILLERMO A BROAD SURFACE TROUGH IS ANALYZED. THE REMNANTS OF TROPICAL DEPRESSION NINE-E HAVE FLARED UP CONVECTIVELY DURING THE LAST SEVERAL HOURS...WITH LARGE CLUSTERS OF DEEP CONVECTION OCCURRING IN THE S SEMICIRCLE. THIS IS OCCURRING IN MILDLY DIVERGENT ELY FLOW ALOFT. SOME MODEST REGENERATION OF THIS SYSTEM MAY BE POSSIBLE OF THIS TREND WERE TO CONTINUE. GAP WINDS... NORTHERLY WINDS OF 20 TO 30 KT WERE DEPICTED IN A MORNING QUIKSCAT PASS IN THE GULF OF TEHUANTEPEC REGION...AND WILL LIKELY CONTINUE FOR ANOTHER 24 HOURS BEFORE DIMINISHING. NE TO E WINDS OF 20 KT IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO REGION OUT TO 90W WILL CONTINUE THROUGH THE NEXT COUPLE OF DAYS. $$ STRIPLING