000 AXPZ20 KNHC 141550 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU AUG 14 2008 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 1515 UTC. ...SPECIAL FEATURE... TROPICAL STORM ISELLE AT 17.8N 109.4W 999 MB AT 1500 UTC MOVING NW OR 305 DEG AT 07 KT. MAXIMUM SUSTAINED WINDS 45 GUSTS TO 55 KT. NUMEROUS STRONG CONVECTION IS NOTED WITHIN 180 NM SW QUADRANT. ISELLE IS FORECAST TO REMAIN A TROPICAL STORM FOR ABOUT 3 DAYS AND THEN WEAKEN AS IT MOVES OVER COOLER WATERS. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. ...TROPICAL LOWS... LOW PRES IS ANALYZED AT 14N120W AT 1008 MB. THIS LOW HAS BEEN MOVING W NW AT 08 KT OVER THE PAST 24 HOURS AND IS EXPECTED TO SLOW ITS FORWARD SPEED AND EVENTUALLY TAKE A MORE NW TURN. NUMEROUS STRONG CONVECTION NOTED WITHIN 180 NM SW QUADRANT. SCATTERED MODERATE ISOLATED STRONG CONVECTION SURROUNDS THE CONVECTIVE BURST ELSEWHERE OUT TO 270 NM SW QUADRANT. THIS LOW HAS THE POTENTIAL TO DEVELOP INTO A TROPICAL CYCLONE OVER THE NEXT FEW DAYS. REMNANT LOW PRES OF HERNAN IS CENTERED NEAR 16N140W AND ESTIMATED AT 1011. IT HAS MOVED SW AT 10 KT OVER THE PAST 24 HOURS. ASCAT PASS AT AROUND 0700 UTC SHOWED A PERSISTENT STRONG WIND FIELD WITH THIS LOW...WITH WINDS 20 TO 30 KT WITHIN 270 NM N SEMICIRCLE. THE CONDITIONS ASSOCIATED WITH THIS REMNANT LOW ARE EXPECTED TO MOVE W OF THE AREA IN THE NEXT 36 HOURS. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 101W AT THE MOMENT AND HAS BEEN MOVING W AT ABOUT 15 KT THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM OF THE WAVE AXIS FROM 08N TO 11N. A TROPICAL WAVE IS ALONG 89W AND HAS BEEN MOVING W AT ABOUT 17 KT THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 240 NM W OF THE AXIS N OF 12N TO THE S MEXICAN/GUATEMALA. ...ITCZ... THE ITCZ AXIS IS ALONG 07N78W TO 12N90W TO 10N98W TO 12N114W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 210 NM N AND 120 NM S OF AXIS BETWEEN 107W AND 116W... WITHIN 90 NM OF AXIS BETWEEN 99W AND 103W...WITHIN 90 NM FROM 84W TO 88W...AND WITHIN 120 NM S AND 60 NM N BETWEEN 77W AND 82W. IN ADDITION...NUMEROUS MODERATE TO STRONG CONVECTION ASSOCIATED WITH THE LOW PRES SYSTEM AT 14N120W CAN BE FOUND WITHIN 180 NM N OF AXIS BETWEEN 120W AND 124W. ...DISCUSSION... THE UPPER LEVEL TROUGH OVER THE NW WATERS IS FORCING THE UPPER LEVEL LOW NEAR 27N120W N AT THIS TIME. THIS TROUGH WILL CONTINUE TO FORCE THE RIDGE AXIS TO ITS S FARTHER S...KEEPING THE REMNANT OF LOW OF HERNAN ON A S OF W TRACK INTO THE CENTRAL PACIFIC. THE TROUGH IS EXPECTED TO SHED SOME SHORTWAVE ENERGY ALONG 135W OVER THE NEXT 24 HOURS. THIS SHOULD HELP MAINTAIN THE MEAN UPPER TROUGH IN THAT REGION SEPARATING THE ANTICYCLONES NEAR 20N141W AND OVER NW MEXICO. UPPER LEVEL DIFFLUENCE ON THE SW EDGE OF THE MEXICAN ANTICYCLONE WILL HELP MAINTAIN THE CONVECTION ASSOCIATED WITH THE LOW PRESSURE SYSTEM NEAR 14N120W AS IT MOVES W OVER THE NEXT 24 HOURS. THE TROPICAL WAVES TRACKING S OF THE ANTICYCLONE OVER MEXICO WILL TRANSPORT DEEP TROPICAL MOISTURE W NW. UPPER LEVEL DIFFLUENCE WILL BE MORE PREVALENT WITH THE FARTHER W TROPICAL WAVE. IN TURN...CONVECTION IS MORE LIKELY WITH THIS SYSTEM OVER THE NEXT DAY OR TWO. STRONG E TO NE UPPER FLOW THROUGH SOUTHERN MEXICO AND MUCH OF CENTRAL AMERICA WILL KEEP HELP PUSH DEBRIS FROM AFTERNOON TSTMS OVER LAND W TOWARD THE COAST. NE FLOW ALOFT CONTINUES W OVER THE DISCUSSION AREA S OF 13N PUSHING DEBRIS MOISTURE SW TO THE EQUATOR E OF 125W. $$ SCHAUER CLARK