000
AXPZ20 KNHC 030940
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON SEP 03 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 
0900 UTC.

...SPECIAL FEATURE...
TROPICAL STORM HENRIETTE AT 19N108W...OR 145 NM W-SW OF CABO 
CORRIENTES MEXICO...AT 03/0900 UTC MOVING NW 7 KT.  MAXIMUM 
SUSTAINED WIND 55 WITH GUSTS TO 65 KT.  ESTIMATED MINIMUM 
CENTRAL PRES 995 MB.  IN SPITE OF A FAVORABLE ENVIRONMENT AT 
ALL LEVELS...HENRIETTE HAS BEEN UNABLE TO STRENGTHEN.  MOST 
LIKELY DUE TO WIND FLOW DISRUPTION BY ITS PROXIMITY TO LAND 
MASS AND HIGH MOUNTAINS.  FORECAST TRACK MAINTAINS SYSTEM UNDER 
SIMILAR CONSTRAIN WITH SLIGHT IMPROVEMENT AT THE MOUTH OF THE 
GULF OF CALIFORNIA WHERE MORE WARM WATER WILL LIKELY ALLOW IT TO 
REACH HURRICANE STRENGTH ALTHOUGH WEAKER THAN PREVIOUSLY 
THOUGHT.  AN EXPECTED TURN TO THE RIGHT BRING HENRIETTE INTO 
LAND IN THE SRN BAJA CALIFORNIA PENINSULA WITH QUICK LOSS OF 
HURRICANE STRENGTH BY WED NIGHT.  SEE LATEST NHC FORECAST/ 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE 
DETAILS.

...TROPICAL WAVES...
TRPCL WAVE ALONG 86W N OF 7N HAS UNFAVORABLE ENVIRONMENT TO 
DEVELOP SIGNIFICANT TSTMS AS STRONG ELY SHEAR PREVAILS OVER 
SYSTEM.  MOST OF PRESENT CONVECTION OVER LAND AND DECREASING 
AS WAVE MOVES W AT 15 KT.  

TRPCL WAVE ALONG 97W N OF 6N MOVING W 15 KT.  WEAK LOW LEVEL 
CIRCULATION 11N97W SHOWS LITTLE ORGANIZATION WITH ISOLATED TSTMS 
ENDURING ADVERSE UPPER LEVEL NE SHEAR.  MOST OTHER CONVECTION 
REMAINS OVER LAND JUST W OF ISTHMUS OF TEHUANTEPEC.

...ITCZ...
ITCZ AXIS CENTERED ALONG 9N80W  11N101W  17N108W  15N121W 
11N140W.  SCATTERED MODERATE CONVECTION WITHIN 180 NM OF AXIS 
FROM 98W TO 106W AND WITHIN 45 NM OF AXIS FROM 135W-139W.

...DISCUSSION...
LARGE AMPLITUDE UPPER LEVEL LONGWAVE ENTERING E PAC NW CORNER 
FROM 32N138W TO WEAK CYCLONE ALOFT AT 26N140W.  VERY DRY AIR 
MASS WITHIN 210 NM EITHER SIDE OF TROUGH AXIS DUE TO STRONG 
SUBSIDENCE.  WELL ANCHORED DEEP LAYER ANTICYCLONE ALONG 120W 
BLOCKS ANY MORE SRN INTRUSION OF TROUGH DIVERTING IT NE.

A SECOND CYCLONE ALOFT NEAR 32N101W HAS UPPER LEVEL TROUGH TO 
24N110W HELPING WEAKEN WINDS OVER HENRIETTE.  A DOWNSTREAM UPPER 
RIDGE WHICH EXTENDS OVER WRN CARIBBEAN SEA MAINTAIN A STEADY 
FLOW OF STRONG ELY WIND ACROSS REMAINDER OF E PAC FEEDING LOW 
LEVEL MOISTURE TO ITCZ BUT CONSTRAINING DEEP CONVECTION WITH ITS 
SHEAR.   

AT THE SURFACE...
ASIDE FROM WIND AND SEAS ASSOCIATED WITH HENRIETTE...ONLY OTHER 
CONCERN WOULD BE THE REMNANTS OF GIL WHICH STILL RUMBLE NEAR 
21N125W OVER COLDER WATERS AND STABLE AIR MASS WITH QUICKLY 
DECREASING WINDS.

ELSEWHERE...MODERATE CROSS-EQUATORIAL SWELLS TO 9 FT S OF 9N E 
OF 130W TO DECREASE IN HEIGHT AND COVERAGE NEXT 36-48 HRS. 
  
$$
WALLY BARNES