000
AXPZ20 KNHC 100339
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN AUG 10 2008

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 
0315 UTC.

...SPECIAL FEATURE...

HURRICANE HERNAN IS CENTERED NEAR 16.7N 124.9W OR ABOUT 925 
NM...1715 KM...WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA 
CALIFORNIA AT 10/0300 UTC MOVING WNW AT 10 KT. MAXIMUM SUSTAINED 
WINDS ARE 100 KT WITH GUSTS TO 120 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 961 MB. HERNAN REMAINS A MAJOR HURRICANE WITH A WELL 
DEFINED 15 NM DIAMETER EYE WITH SCATTERED STRONG CONVECTION 
NOTED WITHIN 120 NM SE SEMICIRCLE. SCATTERED MODERATE ISOLATED 
STRONG ELSEWHERE WITHIN 90 NM NW SEMICIRCLE AND WITHIN 180 NM 
OVER THE SE SEMICIRCLE. HERNAN HAS PEAKED IN INTENSITY AS 
CONVECTION HAS WARMED OVER THE PAST FEW HOURS WITH A HINT OF DRY 
AIR BEGINNING TO ENTRAIN INTO THE N PORTION OF THE CIRCULATION. 
HERNAN IS FORECAST TO STEADILY WEAKEN AND DROP BELOW HURRICANE 
INTENSITY WITHIN 36 HOURS AS IT TRAVERSES OVER SLIGHTLY COOLER 
SEA SURFACE TEMPERATURES. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADER MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS.

...TROPICAL LOWS...

.LOW PRES IS RELOCATED TO NEAR 14N94W 1010 MB. CONVECTION HAS 
DECREASED OVERALL DURING THE LAST SEVERAL HOURS WITH MOST OF THE 
CONVECTION INDICATED WELL TO THE SOUTHEAST OF THE ILL DEFINED 
CENTER. THE LOW IS FORECAST TO POSSIBLY BECOME A TROPICAL 
CYCLONE IN THE NEXT 24 TO 48 HOURS AS IT MOVES WEST-NORTHWEST 
ABOUT 10 KT. THE TROPICAL WAVE THAT HAS BEEN ANALYZED EAST OF 
THE LOW IS NOW DETERMINED TO BE ASSOCIATED WITH THE LOW AND IS 
ANALYZED FROM 18N95W THROUGH THE LOW TO 05N95W. BOTH THE LOW AND 
THE WAVE ARE MOVING WEST ABOUT 10 KT.

...TROPICAL WAVES... 

A TROPICAL WAVE IS ALONG 109W FROM 05N TO 16N MOVING W AT 
ABOUT 10 KT THE PAST 24 HOURS. A SURFACE LOW IS ANALYZED ALONG 
THE WAVE AT AXIS AT 14N ESTIMATED AT 1008 MB. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS CURRENTLY OBSERVED WITHIN 240 NM W 
OF THE WAVE AXIS. 

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE FROM 06N77W TO 
05N90W TO 11N105W TO 15N120W TO 10N130W TO 12N140W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF 06.5N81W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 75 NM OF 
12.5N92.5W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION 
IS WITHIN 60 NM OF 14.5N107.5W AND 15N115W. SCATTERED MODERATE 
WITH ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF 13N137W.

...DISCUSSION...

A LONGWAVE DEEP LAYER TROUGH LIES OVER THE NE PACIFIC ALONG A 
LINE FROM NEAR 35N120W TO 20N140W. A REINFORCING SECONDARY 
TROUGH HAS STRENGTHENED THE NORTHERN PART OF THE TROUGH NORTH OF 
27N. AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER CENTRAL TEXAS 
NEAR 31N101W. SOUTHERLY FLOW BETWEEN THE TROUGH AXIS AND THE 
ANTICYCLONE DOMINATES THE MIDDLE AND UPPER FLOW NORTH OF 17N 
WEST OF A LINE FROM NEAR 32N113W TO 18N121W TO 15N140W. THIS 
AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. IN 
THE LOWER LAYERS OVERCAST STRATOCUMULUS IS NOTED NORTH OF 24N 
BEGINNING ABOUT 180 NM WEST OF THE COAST OF BAJA CALIFORNIA OUT 
TO NEAR 130W WHERE THE CLOUDS BECOME BROKEN TO OVERCAST WEST OF 
130W AND SOUTH OF 25N. MOST MOISTURE ASSOCIATED WITH HERNAN 
CONVECTION IS NOT BEING ADVECTED NORTHWARD BUT IS REMAINING 
SOUTH OF 17N AND SOME IS BEING ADVECTED SOUTH OF THE ITCZ.

NORTH OF THE ITCZ EAST OF ABOUT 115W THE ATMOSPHERE IS MOIST IN 
THE MIDDLE AND UPPER LEVELS WITH AREAS OF MULTI LEVEL CLOUDINESS 
AND EMBEDDED AREAS OF CONVECTION. A WEAK RIDGE ALONG 32N130W TO 
22N110W IS NORTHWEST OF HERNAN. ELSEWHERE EXCEPT FOR THE LOWS 
MENTIONED ABOVE A BROAD TROUGH IS ANALYZED.

$$
COBB