000
AXPZ20 KNHC 082218
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...SPECIAL FEATURES...                                 
HURRICANE HENRIETTE IS CENTERED NEAR 17.1N 139.4W AT 2100 UTC... 
OR ABOUT 940 NM ESE OF HILO HAWAII...MOVING W OR 265 DEG AT 9 
KT. ESTIMATED CENTRAL PRESSURE IS 976 MB. MAXIMUM SUSTAINED 
WINDS 90 KT WITH GUSTS TO 110 KT. HENRIETTE REMAINS A SMALL 
CYCLONE WITH A VERY DISTINCT EYE VISIBLE IN SATELLITE IMAGERY.  
CONVECTION ASSOCIATED WITH HENRIETTE WAS VERY UNIFORM AROUND THE 
CENTER AROUND NOON TODAY...BUT HAS SINCE BEGUN TO ERODE ACROSS 
SE PORTIONS. NUMEROUS STRONG CONVECTION WAS NOTED WITHIN 45 NM 
NW AND 20 NM SE SEMICIRCLES...WHILE SCATTERED MODERATE TO STRONG 
CONVECTION WAS ELSEWHERE WITHIN 75 NM OF CENTER. HENRIETTE IS 
FORECAST TO BEGIN TO TAKE A MORE W-SW MOTION LATER TONIGHT AND 
CONTINUE THIS MOTION...AT AN ACCELERATED SPEED...OVER THE NEXT 
FEW DAYS. OCEANIC AND ATMOSPHERIC CONDITIONS ARE EXPECTED TO BE 
UNFAVORABLE FOR STRENGTHENING BEGINNING TOMORROW...AND A GRADUAL 
WEAKENING TREND IS AGAIN FORECAST. SEE THE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC 
FOR ADDITIONAL DETAILS.

.DEVELOPING LOW PRES CENTERED NEAR 11N110W ESTIMATED AT 1010 MB 
IS SHIFTING W NEAR 10 KT THIS AFTERNOON. CONVECTION ASSOCIATE 
THIS LOW HAS BEGUN TO SHIFT TO THE OUTER PERIPHERY OF THE BROAD 
CIRCULATION...AND VERIFIES THE WEAK WIND FIELD NEAR THE CENTER 
RECENTLY SUGGESTED BY SCATTEROMETER PASSES. SCATTERED MODERATE TO 
STRONG CONVECTION CONTINUES ACROSS THE REGION WITHIN 180 NM S OF 
THE MONSOON TROUGH AXIS. MID TROPOSPHERIC FORCING TO THE W OF A 
MIDDLE TO UPPER LEVEL LOW IS SUGGESTED BY GLOBAL MODELS TO 
INDUCE BAROTROPIC GROWTH OVER THE NEXT FEW DAYS...AND COULD 
ALLOW THIS SYSTEM TO BECOME BETTER ORGANIZED...AND POTENTIALLY 
DEVELOP INTO A TROPICAL CYCLONE. THIS AREA OF LOW PRESSURE HAS A 
MEDIUM CHANCE TO DEVELOP IN A TROPICAL CYCLONE OVER THE NEXT 48 
HOURS AND IT SHIFTS W. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...        
MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 07N73W TO 10N86W 
TO 08N88W TO 11.5N105W TO DEVELOPING LOW PRES NEAR 11N110W 1010 
MB TO 12.5N120W TO 11N132W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED N OF 04N TO TROUGH E OF 85W. SCATTERED MODERATE 
TO STRONG CONVECTION NOTED WITHIN 150 NM N AND 270 NM S OF 
TROUGH BETWEEN 101W AND 118W...AND ALSO WITHIN 240 NM S OF 
TROUGH BETWEEN 125W AND 134W. 

...DISCUSSION...                                                
E OF 110W...WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW NEAR 
13N100W AND CONTINUES TO SHIFT 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 UPPER 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 103W AND 118W. 

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 7 FT OR LESS 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 THIS AFTERNOON TO  
SHIFT W OF ABOUT 137W FRI BEFORE SUBSIDING TO LESS 8 FT THAN 
DURING FRI AFTERNOON. ELSEWHERE...WATER VAPOR IMAGERY SHOWS A 
RATHER LARGE AREA OF BROAD ANTICYCLONIC FLOW COVERING THIS 
PORTION OF THE AREA W OF 120W. TWO ANTICYCLONES ARE 
OBSERVED...ONE AT 20N126W...THE OTHER JUST W OF HENRIETTE AT 
18N142W. 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 1025 MB HIGHS CENTERED NEAR 31N143W...AND THE 
SECOND WELL N OF THE AREA AT 43N145W. 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.

$$
STRIPLING