000
AXPZ20 KNHC 071554
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI AUG 07 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...SPECIAL FEATURES...
HURRICANE FELICIA WAS NEAR 17.9N 135.6W AT 07/1500 UTC WITH 
MAXIMUM SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT. FELICIA WAS 
MOVING WNW OR 295 DEG AT 11 KT WITH AN ESTIMATED MINIMUM CENTRAL 
PRESSURE OF 973 MB. RECENT INFRARED SATELLITE IMAGERY INDICATED 
THAT THE CENTRAL DENSE OVERCAST WAS SHRINKING IN OVERALL AREA
AND THE EYE HAS BECOME LESS DISTINCT AS WELL. SCATTERED TO 
NUMEROUS STRONG CONVECTION WAS NOTED WITHIN 45 NM IN THE NE AND 
60 NM IN THE SW SEMICIRCLES OF FELICIA. SATELLITE IMAGERY ALSO 
SUGGESTS THAT FELICIA CONTINUES TO SEPARATE FROM THE REMNANT LOW 
OF ENRIQUE. HOWEVER FELICIA IS FORECAST TO SLOWLY WEAKEN DURING 
THE NEXT COUPLE OF DAYS AS THE HURRICANE MOVES OVER COOLER 
WATERS AND BEGINS TO ENCOUNTER INCREASING WIND SHEAR. SEE THE 
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS.

TROPICAL DEPRESSION ENRIQUE WAS NEAR 24.4N 129.8W AT 07/1500 
UTC WITH MAXIMUM SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT. 
ENRIQUE WAS MOVING NW OR 320 DEG AT 8 KT WITH AN ESTIMATED 
MINIMUM CENTRAL PRESSURE OF 1007 MB. ENRIQUE HAS LOST MOST 
OF ITS DEEP CONVECTION...WITH A SMALL PATCH OF ISOLATED MODERATE 
THUNDERSTORMS CONFINED TO THE AREA NEAR THE CENTER. A BELT OF 
STRONG UPPER LEVEL SW WINDS ARE MOVING OVER ENRIQUE. THESE WINDS 
COMBINED WITH A FORECAST TRACK OVER COOLER WATERS ARE EXPECTED 
TO CONTRIBUTE TO THE DISSIPATION OF ENRIQUE INTO A REMNANT LOW 
LATER TODAY. 

...TROPICAL WAVES...
A TROPICAL WAVE WAS OVER CENTRAL AMERICA N OF 06N ALONG 
88W/89W....WITH AMPLE MOISTURE OCCURRING BEHIND THIS WAVE ACROSS 
THE SRN CARIBBEAN AND NRN S AMERICA. THIS WAVE HAS BEEN TILTED 
NW TO SE AND STRETCHED SIGNIFICANTLY AS IT MOVED ACROSS THE 
TROPICAL ATLC AND CARIBBEAN...AND IS NOT CURRENTLY INDUCING MUCH 
IN THE WAY OF CONVECTION. 

A TROPICAL WAVE WAS ESTIMATED ALONG 120W FROM 04N TO 15N MOVING 
W NEAR 15 KT. SATELLITE IMAGERY SHOWED A LOW TO MID LEVEL 
CYCLONIC CIRCULATION ASSOCIATED WITH THIS WAVE...AND WAS PART OF 
A BROAD ZONE OF LOW LEVEL CYCLONIC TURNING ACROSS THIS AREA. 
ABUNDANT TROPICAL MOISTURE AND SCATTERED MODERATE CONVECTION WAS 
OCCURRING WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS...BUT WAS 
MORE WIDESPREAD FOR 10 DEGREES BEHIND THE WAVE...SUGGESTING GOOD 
LLVL CONVERGENCE BEING AIDED BY A TRAILING LLVL WIND SURGE.

...ITCZ...
THE AXIS IS FROM 08N77W TO 05N89W TO 10N113W TO 08N124W TO 
12N131W TO 10N140W.  SCATTERED MODERATE ISOLATED STRONG WITHIN 
90 NM N OF AXIS E OF 91W.  ISOLATED MODERATE WITHIN 30 NM OF 
AXIS FROM 87W TO 105W AND WITHIN 210 NM OF AXIS FROM 121W TO 
131W.  SCATTERED MODERATE WITHIN 300 NM N OF AXIS FROM 111W TO 
115W.    

...DISCUSSION...
A LARGE AND DEEP LAYERED TROUGH ACROSS THE WRN U.S. EXTENDS S 
INTO SRN CALIFORNIA...WITH A S/W SWINGING THROUGH THE BASE OF 
THE TROUGH NEAR 32N130W. ELONGATED TROUGHING EXTENDS FROM THIS 
FEATURE TO A BROAD UPPER LOW N OF THE HAWAIIAN ISLANDS. S OF 
THIS ELONGATED CONNECTING TROUGH....S TO SWLY FLOW...AND AN 
ANTICYCLONE OVER FELICIA HAVE AIDED IN MAINTENANCE OF THE 
HURRICANE...WHILE THE STRONG SWLY UPPER FLOW IS INDUCING SHEAR 
OVER ENRIQUE. MODEST UPPER EASTERLIES AND DIFFLUENT FLOW ALOFT 
ARE HELPING TO MAINTAIN AN ACTIVE ITCZ THROUGHOUT THE BASIN W OF 
90W. 

WEAKENING TROPICAL DEPRESSION ENRIQUE HAS BEEN CAPTURED BY A MID 
LEVEL EXTENSION OF THE WRN U.S. TROUGH...WHILE FELICIA HAS MOVED 
WITH A MORE WWD COMPONENT WITH THE TWO SYSTEMS SEPARATING. A MID 
TO UPPER LOW NEAR 19N119W IS MOVING W AND PRODUCING VENTILATION 
TO ITS E...AIDING IN MAINTAINING DEEP CONVECTION ASSOCIATED WITH 
THE TROPICAL WAVE ALONG 120W AND THE PERTURBATION THAT FOLLOWS 
IT. A WIND MAX DIVING DOWN THE BACK SIDE OF THE ERN U.S. UPPER 
TROUGH DURING THE PAST 48 HOURS KICKED OFF DEEP CONVECTION 
ACROSS WRN MEXICO OVERNIGHT...WHERE WIDESPREAD DEEP CONVECTION 
HAS MOVED OFFSHORE JUST N OF CABO CORRIENTES. 

A PERSISTENT...BROAD...AND DEEP LAYER RIDGE OVER THE SOUTH 
CENTRAL UNITED STATES AND NORTHERN MEXICO IS ASSOCIATED WITH A 
SURFACE RIDGE OVER MEXICO THAT BECOMES MOST PRONOUNCED AT NIGHT. 
THE SURFACE PRESSURE GRADIENT TO THE S OF THIS SURFACE RIDGE... 
COMBINED WITH LOCAL VARIATIONS IN TOPOGRAPHY...CONTINUE TO  
SUPPORT A SMALL PLUME OF N TO NE WINDS OF 20 KT IN THE GULF OF 
TEHUANTEPEC.  DURING THE NEXT COUPLE DAYS...THESE WINDS WILL 
LIKELY DIMINISH...AS THE DEEP LAYER RIDGE SLIDES EASTWARD. THE 
CLIMATOLOGICAL BROAD SURFACE RIDGE ACROSS THE E CENTRAL PACIFIC 
IS COMBINING WITH A SURFACE TROUGH OVER FAR NW MEXICO AND THE 
GULF OF CALIFORNIA TO PRODUCE A MODEST PRESSURE GRADIENT OFF THE 
COAST OF BAJA CALIFORNIA...WITH NW WINDS OF 20 TO 25 KT EXPECTED 
TO CONTINUE WITHIN 120 NM W OF THE COAST OF BAJA CALIFORNIA 
DURING THE NEXT FEW DAYS. IN THE GULF OF PAPAGAYO...NE TO E 
WINDS TO 20 KT WILL OCCUR DURING THE NEXT FEW DAYS WITH FRESH TO 
STRONG TRADE WINDS PERSISTING OVER THE CENTRAL AND SW CARIBBEAN.

PULSES OF SRN HEMISPHERE SW SWELL CONTINUE TO INVADE THE 
TROPICAL EPAC AND ARE MAINTAINING SEAS TO 8 FT S OF THE 
EQUATOR...AND GENERALLY 5 TO 7 FT FROM S OF THE BAJA TO PANAMA. 
A NEW PULSE OF THIS SW SWELL IS CURRENTLY REACHING CENTRAL 
AMERICA AND WILL INCREASE ACROSS THE REGION DURING THE NEXT 48 
HOURS.

$$
COBB