000
AXPZ20 KNHC 270248
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI AUG 27 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0130 UTC.

...SPECIAL FEATURES...

AT 27/0300 UTC...HURRICANE FRANK IS CENTERED NEAR 18.2N 111.2W 
MOVING W NW OR 285 DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 980 MB. MAXIMUM SUSTAINED WINDS ARE 75 KT WITH GUSTS 
TO 90 KT. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 NM 
FROM THE CENTER. MAX SEAS ARE ESTIMATED AT 28 FT...WITH 12 FT 
SEAS UP TO 270 NM SE OF THE CENTER. NUMEROUS MODERATE TO STRONG 
CONVECTION LIES WITHIN 30 NM E AND 90 NM W SEMICIRCLE AND 
SCATTERED MODERATE CONVECTION IS ELSEWHERE WITHIN 150 NM EXCEPT 
NE QUADRANT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP4/ WTPZ24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE N OF 07N ALONG 86W MOVING W AROUND 12 KT. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS OVER THE 
GULF OF FONSECA WITHIN 90 NM W OF THE WAVE FROM 12N TO 13N AND 
WITHIN 120 NM E OF THE WAVE N OF 09N OVER SOUTHERN NICARAGUA AND 
NORTHERN COSTA RICA. FARTHER S...SCATTERED MODERATE CONVECTION 
IS WITHIN 120 NM EITHER SIDE OF THE WAVE FROM 06N TO 08N.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 07N87W 
TO 07N103W TO 15N110W TO 12N124W TO 09N140W. SCATTERED MODERATE 
CONVECTION LIES WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 
111W AND 117W.

...DISCUSSION...

AN ANTICYCLONE LIES NEAR 26N117W AND EXTENDS A RIDGE NE ACROSS 
THE CENTRAL GULF OF CALIFORNIA INTO THE NORTHERN SIERRA MADRE 
OCCIDENTAL AS WELL AS SW THROUGH 23N136W TO 20N140W. UPPER LEVEL 
DIFFLUENCE ASSOCIATED WITH FEATURE IS ENHANCING DIURNAL 
CONVECTION INLAND OVER THE NORTHERN SIERRA MADRE OCCIDENTAL. S 
OF THIS RIDGE...A WEAK UPPER TROUGH LIES FROM 23N108W TO 
10N119W. HURRICANE FRANK LIES UNDER THIS WEAK TROUGH AXIS. 
SOUTHEASTERLY WINDS ALOFT ARE EXPECTED TO INCREASE SHORTLY OVER 
FRANK ON THE EASTERN SIDE OF THIS TROUGH. THIS SHEAR IS EXPECTED 
TO WEAKEN FRANK FRI. A LONG WAVE TROUGH MOVING THROUGH THE 
WESTERN U.S. WILL DRAW THIS UPPER TROUGH NORTHWARD FRI AND 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 24N AS WELL AS THE AREA W OF 
125W. SATELLITE PRECIPITABLE WATER IMAGERY ALSO SHOWS DRIER LOW 
TO MID LEVELS ALONG THE ITCZ W OF 125W COMPARED TO E OF THAT 
MARK.

A SURFACE RIDGE LIES FROM 30N133W TO NEAR 25N115W. THE PRES 
GRADIENT IS FORECAST TO BUILD OVER THE N PART OF THE AREA OVER 
THE FORECAST PERIOD BETWEEN THE RIDGE AND TROUGHING ASSOCIATED 
WITH THE LONGWAVE TROUGH MOVING THROUGH THE WESTERN CONUS. SHIP 
DEIP JUST N OF AREA NEAR 31N122W REPORTED 10 FT SEAS AND SHIP 
WDC3786 REPORTED 20 KT WINDS AT 0000 UTC. 20 KT N WINDS ARE 
EXPECTED TO SLOWLY SPREAD SOUTHWARD TO 24N THROUGH SAT. 
ELSEWHERE...FRANK AND ITS ASSOCIATED WEATHER EFFECTS DOMINATE 
SYNOPTIC ENVIRONMENT FROM 13N TO 21N BETWEEN 107W AND 116W.

OUTSIDE OF SWELLS GENERATED BY FRANK..ALTIMETRY SHOWS LONG 
PERIOD S-SW SWELLS PEAKING AT 8-10 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 8-9 FT RANGE OVER EASTERN AND 
CENTRAL WATERS S OF 10N BY SAT NIGHT.

$$
SCHAUER