000
AXPZ20 KNHC 071045
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI AUG 07 2009

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...
HURRICANE FELICIA WAS NEAR 17.2N 134.0W AT 0600 UTC WITH MINIMUM 
CENTRAL PRESSURE OF 960 MB MOVING WNW OR 305 DEG AT 9 KT. 
MAXIMUM SUSTAINED WINDS WERE 100 KT WITH GUSTS TO 120 KT. DEEP 
CONVECTION HAS INCREASED ACROSS THE S SEMICIRCLE...AND TO A 
LESSER DEGREE IN THE N SEMICIRCLE...WHERE CLOUD TOPS HAVE 
RECENTLY COOLED BELOW -70 C. CONVECTION REMAINS MORE SHALLOW IN 
THE WRN SEMICIRCLE...BUT HAS IMPROVED SLIGHTLY IN THE PAST FEW 
HOURS. A WELL DEFINED EYE HAS BEEN APPARENT OVERNIGHT IN STLT 
IMAGERY...10-12 NM WIDE...BUT APPEARS SLIGHTLY MORE ELLIPTICAL 
IN THE MOST RECENT IMAGERY. STLT IMAGERY ALSO SUGGESTS THAT 
FELICIA IS SEPARATING FROM THE MODEST INFLUENCE OR CONNECTION 
THAT HAS EXISTED WITH ENRIQUE...AS FELICIA APPEARS TO HAVE BEGUN 
TO MAKE THE MORE W-NW MOTION FORECAST BY THE GLOBAL MODELS. 
FELICIA IS FORECAST TO SLOWLY WEAKEN DURING THE NEXT COUPLE OF 
DAYS AS THE HURRICANE MOVES OVER COOLER WATERS AND BEGINS TO 
ENCOUNTER UPPER WIND SHEAR. SEE THE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS.

TROPICAL DEPRESSION ENRIQUE WAS ESTIMATED NEAR 24.1N 129.6W AT 
0600 UTC WITH MINIMUM CENTRAL PRESSURE OF 1007 MB MOVING NW OR 
315 DEG AT 12 KT. MAXIMUM SUSTAINED WINDS REMAIN 30 KT WITH 
GUSTS TO 40 KT. SCATTERED MODERATE TO STRONG THUNDERSTORMS 
PERSIST WITHIN 60 NM NE AND 45 NM SE OF THE ESTIMATED CENTER OF 
ENRIQUE...WITH CLOUD TOPS HAVING RECENTLY COOLED SLIGHTLY IN THE 
PAST 2 HOURS. ENRIQUE IS EXPECTED TO WEAKEN FURTHER AND BECOME A 
REMNANT LOW LATER TODAY..THEN DISSIPATE SHORTLY THEREAFTER AS IT 
ENCOUNTERS A MORE HOSTILE ENVIRONMENT. COOLER WATERS LIE AHEAD 
OF ENRIQUE...AND SATELLITE IMAGERY SHOWS INCREASING UPPER WIND 
SHEAR ABOUT TO IMPINGE UPON THE SYSTEM. SEE THE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC 
FOR MORE DETAILS.

...TROPICAL WAVES...
A TROPICAL WAVE WAS OVER CENTRAL AMERICA N OF 06N ALONG 
85W....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 118/119W 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 TO NUMEROUS DEEP CNVTN WAS 
OCCURRING WITHIN A FEW DEGREES OF THIS WAVE...BUT WAS EVEN MORE 
WIDESPREAD FOR 10 DEGREES BEHIND THE WAVE...SUGGESTING GOOD LLVL 
CONVERGENCE BEING AIDED BY A TRAILING LLVL WIND SURGE. THIS LLVL 
WIND SURGE WAS CLEARLY DEPICTED BY SUNY ALBANY GFS ANALYSIS. 

...ITCZ...
THE AXIS IS FROM 09N85W TO 09N100W TO 10N110W TO 07N122W 12N130W 
AND FROM 12N136W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS FROM 07N TO 10N BETWEEN 81W AND 86W. SCATTERED 
MODERATE CONVECTION IS FROM 06N TO 10N BETWEEN 92W AND 
95W...FROM 10N TO 12N BETWEEN 105W AND 110W...AND FROM 07N TO 
10N BETWEEN 110W AND 116W.

...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 
CURRENTLY. 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 THIS MAJOR 
HURRICANE...WHILE THE STRONG SWLY UPPER FLOW IS INDUCING SHEAR 
OVER ENRIQUE. MODEST UPPER ELYS AND DIFFLUENT FLOW ALOFT ARE 
HELPING TO MAINTAIN AN ACTIVE ITCZ W OF 90W. 

ENRIQUE APPEARS TO HAVE BECOME CAPTURED BY A MID LEVEL EXTENSION 
OF THE WRN U.S. TROUGH...WHILE FELICIA HAS BEGUN TO MORE WITH A 
SLIGHTLY MORE WWD COMPONENT...AND THE TWO SYSTEMS ARE 
SEPARATING. A MID TO UPPER LOW ALONG 117W IS MOVING W AND 
PRODUCING VENTILATION TO ITS E...AIDING IN DEEP CNVTN FOR THE 
TROPICAL WAVE AND 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 CNVTN OFF MISSISSIPPI AND 
LOUISIANA LAST NIGHT...AND ACROSS WRN MEXICO OVERNIGHT...WHERE 
WIDESPREAD DEEP CNVTN HAS MOVED OFFSHORE AND INTO THE SRN HALF 
OF THE GULF OF CALIFORNIA.

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 TO 25 KT IN THE 
GULF OF TEHUANTEPEC. THESE WINDS ARE MAINTAINING SEAS TO 8 FT 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 HEMI 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.

$$
STRIPLING