000
AXPZ20 KNHC 270921
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI AUG 27 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 
0800 UTC.

...SPECIAL FEATURES...

AT 27/0900 UTC...

HURRICANE FRANK IS CENTERED NEAR 18.6N 112.1W MOVING W-NW OR 285 
DEG AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB. 
MAXIMUM SUSTAINED WINDS ARE 70 KT WITH GUSTS TO 85 KT. SEE 
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/ 
WTPZ24 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO STRONG 
CONVECTION IS FROM 17N TO 19N BETWEEN 111W AND 114W.

...TROPICAL WAVES...

TROPICAL WAVE N OF 08N ALONG 87W MOVING W NEAR 10 KT. SCATTERED 
MODERATE TO STRONG CONVECTION WITHIN 120 NM ALONG THE COAST OF 
NICARAGUA AND EL SALVADOR BETWEEN THE WAVE AXIS AND 90W.    

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 08N87W 
TO 07N102W THEN RESUMES NEAR 13N113W TO 11N118W TO 12N129W TO 
09N140W. SCATTERED MODERATE CONVECTION IS N OF 07N BETWEEN 78W 
AND 81W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
FROM 12N TO 15N BETWEEN 92W AND 95W. 

...DISCUSSION...

AN UPPER ANTICYCLONE LIES NEAR 26N127W EXTENDING A RIDGE NE 
ACROSS THE N/CENTRAL GULF OF CALIFORNIA INTO THE NORTHERN SIERRA 
MADRE OCCIDENTAL AS WELL AS SW TO 20N140W. UPPER LEVEL 
DIFFLUENCE ASSOCIATED WITH FEATURE IS ENHANCING DIURNAL 
CONVECTION INLAND OVER THE NORTHERN SIERRA MADRE OCCIDENTAL. S 
OF FRANK IS A WEAK UPPER TROUGH FROM 25N108W TO 10N111W. 
SOUTHEASTERLY WINDS ALOFT ARE EXPECTED TO INCREASE OVER FRANK 
AND THIS SHEAR IS EXPECTED TO WEAKEN FRANK LATER TODAY. A LONG 
WAVE TROUGH MOVING THROUGH THE WESTERN U.S. WILL DRAW THIS UPPER 
TROUGH NORTHWARD FRI INTO SAT. THIS DEEP LAYER TROUGH 
APPROACHING FROM THE NORTH WILL ALSO CURVE FRANK ON A MORE 
NORTHERLY TRACK SAT. ELSEWHERE...WATER VAPOR IMAGERY SHOWS 
MODERATE SUBSIDENCE AND DRIER AIR ALOFT OVER A LARGE PORTION OF 
THE AREA N OF 23N AS WELL AS THE AREA W OF 130W. 

A SURFACE RIDGE LIES N OF 22N W OF 125W. THE PRES GRADIENT IS 
FORECAST TO BUILD OVER THE NW PART OF THE AREA OVER THE FORECAST 
PERIOD BETWEEN THE RIDGE AND TROUGHING ASSOCIATED WITH THE 
LONGWAVE TROUGH MOVING THROUGH THE WESTERN CONUS. NORTH WINDS OF 
20 KT ARE EXPECTED TO SLOWLY SPREAD SOUTHWARD TO 24N THROUGH 
SAT. ELSEWHERE...FRANK AND ITS ASSOCIATED WEATHER EFFECTS 
DOMINATE SYNOPTIC ENVIRONMENT FROM 10N TO 23N BETWEEN 108W AND 
117W.

OUTSIDE OF SWELLS GENERATED BY FRANK..ALTIMETRY SHOWS LONG 
PERIOD S-SW SWELLS PEAKING AT 8 TO 10 FT S OF THE HURRICANE. 
SEAS IN THIS AREA ARE EXPECTED TO GRADUALLY SUBSIDE FRI...BUT A 
NEW ROUND OF CROSS-EQUATORIAL SWELL WILL MOVE INTO THE AREA BY 
SAT MORNING AND BRING SEAS BACK TO THE 8 TO 9 FT RANGE OVER 
EASTERN AND CENTRAL WATERS S OF 10N BY SAT NIGHT.

$$
PAW