000
AXPZ20 KNHC 240908
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE AUG 24 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 FEATURE...

AT 24/0900 UTC...TROPICAL STORM FRANK IS CENTERED NEAR 15.3N 
100.9W MOVING WNW OR 285 DEGREES AT 8 KT. A WEST-NORTHWEST 
MOTION IS EXPECTED TO CONTINUE DURING THE NEXT COUPLE OF DAYS.  
ON THE FORECAST TRACK...FRANK IS EXPECTED TO MOVE PARALLEL TO THE
COAST OF SOUTHERN AND SOUTHWESTERN MEXICO THROUGH WEDNESDAY. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED 
WINDS ARE 45 KT WITH GUSTS TO 55 KT. LITTLE CHANGE IN STRENGTH 
IS LIKELY TODAY...BUT SOME SLIGHT STRENGTHENING IS POSSIBLE ON 
WEDNESDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. NUMEROUS 
MODERATE SCATTERED STRONG CONVECTION IS WITHIN 120 NM SW AND W 
QUADRANTS OF CENTER. 

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 07N78W TO 
11N94W THEN RESUMES AT 13N103W TO 12N121W TO 10N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS WITHIN 90 NM S OF AXIS E 
OF 80W.

...DISCUSSION...

AN UPPER ANTICYCLONE IS CENTERED NEAR 30N135W WITH THE RIDGE 
AXIS EXTENDING TO 19N142W. VERY DRY AIR UNDER MODERATE TO STRONG 
SUBSIDENCE IS NOTED ACROSS THE AREA N OF 16N AND W OF 135W. AN 
INVERTED TROUGH IS E OF THIS RIDGE STRETCHING FROM 32N125W TO 
18N126W. ABUNDANT MID TO UPPER LEVEL MOISTURE IS NOTED BETWEEN 
THE TROUGH AXIS AND 135W. ANOTHER UPPER ANTICYCLONIC CIRCULATION 
IS NEAR 29N116W WITH A RIDGE EXTENDING TO 19N115W. AN UPPER 
LEVEL LOW IS SPINNING NEAR 22N115W. EASTERLY WINDS ON THE 
SOUTHERN PERIPHERY OF A LARGE SCALE UPPER ANTICYCLONE OVER FAR 
SOUTHERN TEXAS ARE FORECAST BY THE COMPUTER MODELS TO REMAIN 
STRONG ENOUGH TO PREVENT FRANK FROM STRENGTHENING INTO A 
HURRICANE OVER THE NEXT SEVERAL DAYS. NE-E WIND FLOW COVERS THE 
MAJORITY OF THE DEEP TROPICS. 

AT THE SURFACE...A RIDGE DOMINATES THE FORECAST REGION N OF 20N 
AND W OF 120W. A 1010 MB LOW IS EMBEDDED IN THE ITCZ AXIS NEAR 
13N122W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE 
CENTER. 20 KT WINDS ARE OCCURRING WITHIN 150 NM S AND 60 NM N 
SEMICIRCLES OF CENTER. AN ASCAT PASS FROM 0502 UTC CONFIRMED 
THESE WIND SPEEDS. THE LOW IS FORECAST TO CONTINUE TO DRIFT TO 
THE E AND DISSIPATE IN ABOUT 48 HOURS. A SECOND WEAK LOW IS 
ANALYZED NEAR 13N132W. ISOLATED TO SCATTERED SHOWERS ARE NEAR 
THE LOW CENTER. A WEAK TROUGH WHICH IS THE REMNANTS OF T.D. 
EIGHT-E EXTENDS ALONG 116W FROM 18N TO 22N. NO CONVECTION IS 
NOTED WITH THIS FEATURE.

CROSS EQUATORIAL S AND SW SWELLS WITH PEAK WAVE PERIODS OF 18-20 
SECONDS CONTINUES TO AFFECT THE REGIONAL WATERS...EXCEPT JUST N 
OF THE GALAPAGOS ISLANDS...WITH COMBINED SEAS OF 8-11 FT. THIS 
SWELL TRAIN WILL CONTINUE TO PROPAGATE AND EXPAND TO THE N ALL 
THE WAY TO THE U.S. CALIFORNIA COAST DURING THE NEXT 24 HOURS 
THEN WILL GRADUALLY SUBSIDE BEGINNING BETWEEN 36-48 HOURS WHILE 
SE SWELL BECOMES MORE DOMINANT OVER THE FAR SW PORTION OF THE 
AREA.

$$
GR