000
AXPZ20 KNHC 020949
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN SEP 02 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0915 UTC.

...SPECIAL FEATURES...

TROPICAL STORM HENRIETTE CENTERED NEAR 18.5N 107.0W...OR 140 NM 
WSW OF MANZANILLO MEXICO...AT 02/0900 UTC MOVING WNW 8 KT. 
MAXIMUM SUSTAINED WINDS 60 KT WITH GUSTS TO 75 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 994 MB. HENRIETTE CONTINUES TO 
BECOME BETTER ORGANIZED AND SYMMETRICAL WITH CONVECTIVE BANDS 
INCREASING IN ALL QUADRANTS.  HENRIETTE IS STARTING TO GRADUALLY 
MOVE AWAY FROM THE MANZANILLO TO PUERTO VALLARTA AREA...HEAVY 
RAINFALL IS STILL POSSIBLE OVER INLAND MOUNTAINS FROM GUERRERO 
TO SINALOA. HENRIETTE IS EXPECTED TO STRENGTHEN TO A HURRICANE 
TODAY. THE CENTER OF HENRIETTE WILL MOVE TO WITHIN 170 NM SW OF 
CABO SAN LUCAS BY MON NIGHT. IT WILL THEN GRADUALLY MOVE MORE TO 
THE N INTO COOLER WATERS WHERE IT WILL BEGIN TO WEAKEN TO 
TROPICAL STORM STRENGTH...REACHING THE NRN COAST OF BAJA BY LATE 
THU. 
SEE THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

TROPICAL DEPRESSION GIL IS CENTERED NEAR 19.5N 123.2W...OR 775 
NM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA...AT 02/0900 UTC 
MOVING WNW 8 KT. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH 
GUSTS TO 35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE REMAINS 1005 
MB. CONVECTION FROM THE PREVIOUS EVENING HAS DISSIPATED OVER THE 
PAST FEW HOURS. HOWEVER...MODERATE CONVECTION WILL CONTINUE TO 
PULSE MAINLY JUST TO THE W OF THE SURFACE CENTER THROUGH TODAY. 
THE DEPRESSION IS EXPECTED TO WEAKEN TO A REMNANT LOW BY LATE 
TODAY AS IT MOVES FURTHER INTO A DRIER AND MORE STABLE 
ENVIRONMENT WHILE EXPERIENCING ELY SHEAR ALOFT. SEE LATEST NHC 
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC 
FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 91W MOVING W 10-15 KT ACROSS GUATEMALA. THE 
WAVE PROXIMITY TO HENRIETTE MAKES IT DIFFICULT TO DISCERN AS A 
DISTINCT FEATURE. QUIKSCAT IMAGERY AND SATELLITE ANALYSIS HINT 
OF WEAK CYCLONIC TURNING S OF GUATEMALA...ALTHOUGH IT IS NOT 
CLEAR.  
  
...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N85W 17N103W 10N130W 9N140W. 
SCATTERED MODERATE CONVECTION WITHIN 120 NM S OF AXIS BETWEEN 
100W AND 105W.

...DISCUSSION...

E OF 120W...
UPPER LEVEL TROUGH EXTENDS FROM THE BIG BEND AREA OF TEXAS TO W 
CENTRAL MEXICO NEAR MAZATLAN. THIS HAS PUSHED AN UPPER 
ANTICYCLONE THAT WAS OVER NW MEXICO LAST SEVERAL DAYS FURTHER W 
TO 32N122W...RESULTING IN MUCH WEAKER SHEAR OFF THE W COAST OF 
CENTRAL MEXICO THAN BEFORE. THIS IN TURN IS ALLOWING HENRIETTE 
TO STRENGTHEN. THE SWLY FLOW ALOFT ON THE E SIDE OF THE UPPER 
TROUGH IS ALSO ADDING A GOOD EXHAUST MECHANISM TO HENRIETTE'S 
UPPER OUTFLOW...AND DELIVERING DEEP LAYER MOISTURE ACROSS TEXAS 
AND THE DEEP SOUTH. NELY SHEAR ALOFT IS STILL A FACTOR TO THE S 
OF THE STORM HOWEVER...FROM SRN MEXICO THROUGH CENTRAL AMERICA. 
THIS IS HELPING TO SUPPRESS MUCH OF THE CONVECTION IN THE AREA 
OUTSIDE OF HENRIETTE...EVEN AS A PAIR OF TROPICAL WAVES ENTER 
THE ERN PACIFIC FROM THE CARIBBEAN. THE FORECAST IS OF COURSE 
DOMINATED BY THE DEVELOPMENT AND TRACK OF HENRIETTE. IT IS 
EXPECTED TO DEVELOP INTO A HURRICANE TODAY AND MOVE NW AROUND 
THE SRN TIP OF BAJA THROUGH TUE...THEN MOVE MORE N INTO CENTRAL 
BAJA BY LATE THU AS A TROPICAL STORM. FURTHER S...RESIDUAL 
MODERATE TO LARGE SWELL CONTINUES TO MOVE N ACROSS THE EQUATOR W 
OF 95W. THE WAVE WATCH MODEL SHOWS THIS SUBSIDING OVER THE NEXT 
24-48 HOURS.

W OF 120W...
THE UPPER ANTICYCLONE CENTERED NEAR 32N122W WILL CONTINUE TO 
PROVIDE ELY SHEAR AND STEERING FLOW TO T.D. GIL AS IT MOVES W 
AND WEAKENS OVER THE NEXT COUPLE OF DAYS. BOUNDARY LAYER FLOW 
HAS BEEN STEADILY OUT OF THE N-NE OVER THE LAST COUPLE OF 
DAYS...STABILIZING THE LOWER AND MID LEVELS. DEEP LAYER MOISTURE 
REMAINS ANEMIC OUTSIDE OF GIL...THUS CONVECTIVE DEVELOP OVER THE 
REST OF THE AREA IS VIRTUALLY NIL. THERE MAY BE SOME MODEST 
INCREASE IN THE N TO NE SURFACE FLOW TO THE NW OF GIL THROUGH 
TODAY. HOWEVER...DEEP TROUGHING EMERGING OUT OF THE N CENTRAL 
PACIFIC HAS WEAKENED THE SURFACE HIGH PRES TO THE NW OF THE 
AREA...THUS WINDS AND SEAS MAY NOT INCREASE APPRECIABLY AS THE 
REMNANT LOW OF GIL MOVES W.

   
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CHRISTENSEN