000 AXPZ20 KNHC 010357 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT SEP 01 2007 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0330 UTC. ...SPECIAL FEATURES... RECENTLY DOWNGRADED TROPICAL STORM GIL WAS CENTERED NEAR 18.6N 119.0W...OR ABOUT 550 NM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA...AT 01/0300 UTC MOVING W 8 KT. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. THE CENTER OF GIL IS NOW EXPOSED WITH SCATTERED MODERATE CONVECTION MOSTLY DISPLACED WITHIN 90 MM W SEMICIRCLE. ALL INDICATIONS ARE IT WILL EITHER MAINTAIN ITS CURRENT INTENSITY OR WEAKEN SLIGHTLY OVER THE NEXT 3 DAYS...WHILE CONTINUING ON A GENERAL W THEN WNW TRACK. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. TROPICAL STORM HENRIETTE CENTERED NEAR 17.1N 102.1W...OR ABOUT 170 NM SE OF MANZANILLO MEXICO. HENRIETTA IS MOVING WNW AT 10 KT...AND ON THIS TRACK THE CENTER OF THE TROPICAL STORM IS EXPECTED TO MOVE NEAR OR PARALLEL TO THE SOUTHWEST COAST OF MEXICO. HOWEVER...ANY DEVIATION TO THE NORTH OF THE TRACK WOULD BRING STRONGER WINDS TO THE COAST. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS. HENRIETTE IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 4 TO 8 INCHES ALONG THE SOUTH COAST OF MEXICO FROM GUERRERO TO JALISCO...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 15 INCHES. LIFE-THREATENING FLASH FLOODS AND MUDSLIDES ARE POSSIBLE. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO STRONG ASSOCIATED WITH HENRIETTE IS FROM 15N-21N BETWEEN 97W-107W. ...ITCZ... AXIS CENTERED ALONG 9N84W 16N100W 18N115W 12N130W 9N140W. ISOLATED MODERATE CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 82W-97W...AND S OF THE AXIS FROM 15N-18N BETWEEN 110W-115W. ...DISCUSSION... E OF 120W... THE MAIN ISSUE IS THE DEVELOPMENT AND TRACK OF TROPICAL STORM HENRIETTE ALONG THE MEXICAN COAST. GRADUAL STRENGTHENING IS EXPECTED OF HENRIETTE WITH THE SHEAR EXPECTED TO RELAX AND SSTS WARM. HEAVY RAINFALL IS A BIG CONCERN FOR A PORTION OF THE MEXICAN COAST. THE OTHER ISSUE IS TROPICAL STORM GIL. SEE SPECIAL FEATURES ABOVE FOR DETAILS. THE MODERATE TO STRONG SHEAR AFFECTING BOTH OF THESE SYSTEMS IS DUE TO NE/E FLOW ALOFT BETWEEN AN UPPER LOW OVER THE SW CARIBBEAN...AND BROAD UPPER RIDGING OVER NRN BAJA AND BUILDING OVER CENTRAL MEXICO. ASIDE FROM HIGH WINDS AND ROUGH SEAS NEAR THE STORM...MODERATE TO FRESH SWLY WINDS ARE DIRECTLY S OF GIL AS FAR AS S AS 7N AS NOTED IN AN EARLIER QUIKSCAT PASS. ELSEWHERE S OF THE ITCZ...S TO SW CROSS-EQUATORIAL FLOW REMAINS LIGHT TO MODERATE. THIS CONTINUES TO BE ACCOMPANIED BY MODERATE MIXED SE AND SW SWELLS OF UP TO 9 FT OUT OF THE SRN HEMISPHERE...MAINLY W OF 95W. W OF 120W... THE UPPER FLOW ACROSS THIS AREA IS SOMEWHAT CONFLUENT BETWEEN A WELL DEFINED UPPER RIDGE CENTERED OVER NRN BAJA AND AN UPPER LOW JUST N OF THE HAWAIIAN ISLANDS. THIS STABLE ENVIRONMENT IS SUPPRESSING ANY DEEP CLOUD FORMATION ESPECIALLY W OF 130W. EVEN THE ITCZ IS DEVOID OF DEEP CONVECTION. SOME OF THIS STABLE AIR CONTINUES TO AFFECT TROPICAL DEPRESSION GIL...LOCATED JUST E OF THIS ZONE. AS GIL MOVES DEEPER INTO THIS STABLE AIRMASS FURTHER INTENSIFICATION IS LESS LIKELY. HOWEVER...WINDS AND SEAS ARE EXPECTED TO PICK UP IN THIS AREA THROUGH TONIGHT AS GIL CROSSES 120W. MODERATE CROSS EQUATORIAL SWELL AND SLIGHTLY INCREASED SLY FLOW IS EXPECTED S OF THE ITCZ AS WELL. $$ WILLIS