000 AXPZ20 KNHC 081609 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU AUG 08 2013 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...SPECIAL FEATURES... HURRICANE HENRIETTE IS CENTERED NEAR 17.2N 138.3W AT 1500 UTC MOVING W OF 280 DEG AT 9 KT. ESTIMATED CENTRAL PRESSURE IS 980 MB. MAXIMUM SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT. DURING THE EARLIER MORNING HOURS...THE OVERALL STRUCTURE OF THE CYCLONE HAS BECOME MORE SYMMETRICAL...AND IMPRESSIVE IN THE OBSERVED DEEPENING OF THE CONVECTION AROUND WHAT NOW APPEARS TO BE AN EYE FEATURE. THE CYCLONE IS PRESENTLY UNDER FAVORABLE UPPER LEVEL WINDS. NUMEROUS STRONG CONVECTION IS NOTED WITHIN 45 NM OF CENTER. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE WITHIN 90 NM NE AND 60 NM OF SW SEMICIRCLES. HENRIETTE IS FORECAST TO BEGIN TO UNDERGO A WEAKENING TREND LATER THIS MORNING AND AFTERNOON AS IT BEGINS TO TRACK A LITTLE MORE TO THE NW OVER MARGINAL SEA SURFACE TEMPERATURES...AND WHILE W TO SW VERTICAL SHEAR ALSO SETS IN. HENRIETTE IS FORECAST BY THE LATEST NHC ADVISORY TO REACH NEAR 17.3N 139.7W BY EARLY THIS EVENING...AND TO W OF THE AREA NEAR 17.0N 141.6W AS A MINIMAL HURRICANE BY BY EARLY SAT MORNING. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR ADDITIONAL DETAILS. .LOW PRES CENTERED NEAR 11N111W WITH A PRES OF 1008 MB IS MOVING W AT 16 KT. CONVECTION ASSOCIATE THIS THIS LOW HAS DIMINISHED DURING THE PAST SEVERAL HOURS...WITH ONLY WIDELY SCATTERED SHOWERS AND TSTMS SEEN WITHIN 120 NM OF THE LOW IN THE W SEMICIRCLE. WINDS ARE CURRENTLY 20 KT OR LESS WITH THIS LOW...BUT ARE EXPECTED TO DEVELOP TO THE 20-25 KT RANGE WITHIN ABOUT 240 NM OF THE CENTER PRIMARILY TO ITS E AND SE OVER THE NEXT 24-48 HRS. THE LOW HAS A POTENTIAL TO DEVELOP IN A TROPICAL CYCLONE OVER THE NEXT 48 HRS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 07N78W TO 10N90W TO LOW PRES NEAR 11N108W 1008 MB TO 11N120W TO ANOTHER LOW NEAR 10N127W 1011 MB AND TO 11N132W. SCATTERED MODERATE TO STRONG CONVECTION IS SEEN WITHIN 180 NM S OF THE AXIS BETWEEN 128W-134W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF AXIS BETWEEN 77W-80W...AND ALSO WITHIN 150 NM-180 NM S OF THE AXIS BETWEEN 100W-116W. ...DISCUSSION... E OF 110W...WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW NEAR 12N98W AND CONTINUES TO SHIFT SLOWLY WESTWARD UNDERNEATH A BROAD UPPER RIDGE ACROSS THE GULF OF MEXICO AND SE MEXICO. LOW TO MIDDLE LEVEL NE TO E FLOW ALOFT W OF THIS LOW AND ON THE SW PERIPHERY OF THIS UPPER RIDGE CONTINUES TO INITIATE CLUSTERS OF WIDELY SCATTERED TO SCATTERED MODERATE CONVECTION N OF THE MONSOON TROUGH TO 15N BETWEEN 99W AND 110W. OTHERWISE...MONSOONAL FLOW DOMINATES THE REGION S OF THE TROUGH AND AREAS TO THE W TO SW...WITH S TO SW WINDS GENERALLY LESS THAN 20 KT. SEAS REMAIN AT LESS THAN 7 FT ACROSS THIS PORTION OF THE DISCUSSION AREA. W OF 110W...THE MAIN FEATURE IS HURRICANE HENRIETTE. PLEASE SEE THE LATEST NHC TROPICAL CYCLONE DISCUSSION ON HENRIETTE UNDER AWIPS/WMO HEADERS MIATCDEP3/WTPZ43 KNHC FOR RELATED DETAILS ABOUT THIS CYCLONE. EXPECT SWELL RELATED TO HENRIETTE OF GREATER THAN 8 FT GENERALLY FROM 14N TO 22N W OF 131W THROUGH TODAY... AND SHIFTING TO W OF ABOUT 137W FRI BEFORE SUBSIDING TO LESS THAN DURING FRI AFTERNOON. ELSEWHERE...SATELLITE WATER VAPOR IMAGERY SHOWS A RATHER LARGE AREA OF BROAD ANTICYCLONIC FLOW COVERING THIS PORTION OF THE AREA. TWO ANTICYCLONES ARE OBSERVED...ONE AT 20N132W...THE OTHER JUST W OF THE AT 18N141W. HENRIETTE IS BETWEEN BOTH OF THESE ANTICYCLONES. A WEAK UPPER TROUGH STRETCHES INTO THE AREA THROUGH 32N124W AND TO NEAR 30N140W BEFORE IT BECOMES DIFFUSE. AT THE SURFACE...BROAD HIGH PRESSURE IS CENTERED N OF THE AREA ANCHORED BY A PAIR OF 1023 MB HIGHS CENTERED NEAR 31N143W...AND WELL N OF THE AREA AT 42N147W. THE HIGHS ARE BISECTED BY A COLD FRONT SUPPORTED BY THE AFOREMENTIONED UPPER TROUGH. THE COLD FRONT IS IS FORECAST TO WEAKEN AS IT MOVES TO THE ESE JUST BRUSHING THE FAR NORTHERN WATERS OVER THE NEXT 48 HOURS. $$ AGUIRRE