000
AXPZ20 KNHC 260920
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU AUG 26 2010

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 FEATURES...

AT 26/0900 UTC...HURRICANE FRANK IS CENTERED NEAR 17.5N 108.7W 
MOVING W-NW OR 285 DEG AT 12 KT...AND THIS GENERAL MOTION IS 
EXPECTED TO CONTINUE FOR THE NEXT DAY OR SO. A REDUCTION IN 
FORWARD SPEED IS LIKELY TO OCCUR ON FRIDAY. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 984 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 
KT WITH GUSTS TO 85 KT. FRANK IS A CATEGORY ONE HURRICANE ON THE 
SAFFIR-SIMPSON SCALE. SOME STRENGTHENING IS FORECAST TODAY...AND 
A GRADUAL WEAKENING TREND IS EXPECTED TO BEGIN ON FRIDAY AS THE 
TROPICAL CYCLONE MOVES OVER COOLER WATERS. NUMEROUS MODERATE TO 
STRONG WITHIN 180 NM SW AND 60 NM NE SEMICIRCLES. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/ WTPZ24 KNHC 
FOR MORE DETAILS.

...TROPICAL WAVE...

A TROPICAL WAVE ALONG 82W N OF 07N IS MOVING W AROUND 15 KT. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NEAR THE 
SOUTHERN END OF THE WAVE N OF 8N BETWEEN 82W AND 84W. 

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED ALONG 07N78W 
TO 05N90W TO 08N97W THEN RESUMES AT 13N108W TO 11N130W TO 
08N140W. SCATTERED MODERATE ISOLATED STRONG FROM 05N TO 08N E OF 
80W. SCATTERED MODERATE WITHIN 60 NM EITHER SIDE OF AXIS FROM 
118W TO 124W. 

...DISCUSSION...

ALOFT...AN ANTICYCLONIC CIRCULATION IS CENTERED NEAR 26N115W 
WITH A RIDGE EXTENDING MAINLY WWD TO BEYOND 23N140W. UPPER LEVEL 
DIFFLUENCE ASSOCIATED WITH FEATURE IS ENHANCING CONVECTION 
WITHIN 30-50 NM OF THE COAST OF MAINLAND MEXICO FROM 21N TO 26N. 
HURRICANE FRANK IS MOVING AROUND THE SOUTHERN PERIPHERY OF THIS 
RIDGE. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. 
SATELLITE WATER VAPOR IMAGERY SHOWS MOSTLY MODERATE SUBSIDENCE 
AND DRY AIR PRESENT OVER A LARGE PORTION OF THE AREA OUTSIDE THE 
ITCZ REGION N OF 16N W OF 121W. NE TO E WINDS ALOFT DOMINATE THE 
AREA E OF 110W.

AT THE SURFACE...A RIDGE IMPACTS MUCH OF THE REGION N OF 18N W 
OF 120W. TO THE S...A PAIR OF 1010 MB WEAK LOWS ARE EMBEDDED 
WITHIN THE ITCZ. THE FIRST LOW IS CENTERED NEAR 12N115W AND 
REMAINS NEARLY STATIONARY. THIS LOW IS FORECAST TO DISSIPATE 
OVER THE NEXT 24 HOURS. THE SECOND LOW IS NEAR 11N132W. THIS 
WESTERN LOW IS FORECAST TO WEAKEN TO A TROUGH AND SLOWLY MOVE W 
OVER THE NEXT DAY OR TWO. SCATTERED SHOWERS ARE ASSOCIATED WITH 
BOTH LOWS. FARTHER N...THE PRES GRADIENT IS FORECAST TO BUILD 
OVER N CENTRAL WATERS LATE FRI INTO SAT BETWEEN THE RIDGE OVER 
NW WATERS AND DEEPENING LOW PRES IN THE U.S. GREAT BASIN. EXPECT 
N WINDS OF 20 KT AND SEAS OF 8 FT N OF 28N BETWEEN 121W AND 133W.

ASIDE FROM MARINE CONDITIONS ASSOCIATED WITH HURRICANE FRANK... 
CROSS EQUATORIAL S AND SW SWELLS WITH PEAK WAVE PERIODS OF 13-15 
SECONDS CONTINUE TO BUILD SEAS TO THE 8-11 FT RANGE OVER MUCH OF 
THE AREA BETWEEN 80W AND A LINE FROM 21N115W TO 10N135W TO 
00N135W EXCEPT N OF THE GALAPAGOS ISLANDS. THIS AREA OF SEAS 
OVER 8 FT WILL GRADUALLY SHRINK OVER THE NEXT COUPLE OF DAYS AS 
PERIODS SHORTEN BELOW 13 SECONDS. 

$$
GR