000
AXPZ20 KNHC 070336
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU AUG 07 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...

NEWLY UPGRADED TROPICAL STORM HERNAN CENTERED NEAR 13.8N 112.5W 
OR ABOUT 565 NM...1050 KM SOUTH-SOUTHWEST OF THE SOUTHERN TIP 
OF BAJA CALIFORNIA AT 07/0300 UTC MOVING WNW AT 12 KT. MAXIMUM 
SUSTAINED WINDS HAVE INCREASED TO 35 KT WITH GUSTS TO 45 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMEP4/WTPZ24 KNHC 
FOR MORE DETAILS. OVERALL CONVECTION CONTINUES TO BECOME BETTER 
ORGANIZED DESPITE MODERATE EASTERLY SHEAR AND THUS THE SYSTEM 
HAS BEEN UPGRADED TO THE EIGHT NAMED STORM OF THE YEAR...HERNAN. 
HERNAN IS FORECAST TO GRADUALLY STRENGTHEN OVER THE NEXT 48 
HOURS...POSSIBLY BECOMING A HURRICANE. CURRENTLY...SCATTERED TO 
NUMEROUS STRONG WITHIN 120 NM SW SEMICIRCLE. SCATTERED MODERATE 
ISOLATED STRONG ELSEWHERE WITHIN 240 NM W AND 60 NM E 
SEMICIRCLES.

...TROPICAL WAVES... 

A TROPICAL WAVE IS LOCATED ALONG 97W N OF 06N EXTENDING 
NORTHWARD INTO MEXICO. THE WAVE IS MOVING W ABOUT 10 KT. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN
240 NM W OF THE WAVE AXIS...GENERALLY FROM 8N TO 14N. DESPITE 
THE PRESENCE OF THE CONVECTION...THE WAVE REMAINS WEAK AND 
DISORGANIZED.

A TROPICAL WAVE IS LOCATED ALONG 130W FROM 05N TO 17N AND IS 
MOVING W ABOUT 10 KT. THE WAVE IS WEAK WITH MINIMAL CONVECTION 
ASSOCIATED WITH IT. 

...ITCZ...

ITCZ AXIS ALONG 09N84W TO 08N90W TO 14N108N TO 09N122W TO 
10N140W. SCATTERED MODERATE TO STRONG WITHIN 60 NM OF 5.5N92.5W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 180-240 NM OF THE AXIS 
BETWEEN 97W AND 106W...WITHIN 120 NM N OF THE AXIS BETWEEN 133W 
AND 136W. 

...DISCUSSION...

W OF 105W...
A MIDDLE/UPPER LEVEL TROUGH WITH AXIS ALONG 130W N OF 25N IS 
MOVING E ABOUT 10-15 KT. CYCLONIC FLOW IS INDICATED UP TO 10 
DEGREES EITHER SIDE OF THE WAVE AXIS AND GENERALLY COVERS THE 
FAR NW PORTION OF THE AREA. FURTHER S AND E AN ELONGATED 
MIDDLE/UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 
22N114W. THIS FEATURE IS NEARLY STATIONARY. MODERATE TO STRONG
EASTERLY WINDS ALOFT ARE LOCATED SOUTH OF THE ANTICYCLONE/RIDGE 
AXIS BETWEEN 100W AND 130W. TROPICAL STORM HERNAN IS EMBEDDED 
WITHIN THIS FLOW AND AS A CONSEQUENCE IS EXPERIENCING EASTERLY 
SHEAR. CIMSS SHEAR ANALYSES INDICATE EASTERLY SHEAR OF UP TO
20 KT OVER THE CYCLONE. AT THE SURFACE HIGH PRESSURE DOMINATES 
THE AREA N OF 15N W OF 115W WITH THE RIDGE AXIS LOCATED THROUGH 
30N132W TO 20N114W.

E OF 105W...
THE FLOW ALOFT OVER THE E PART OF THE DISCUSSION AREA IS MOSTLY 
EASTERLY. AT THE SURFACE FROM 10N TO 12N E OF 90W...INCLUDING 
THE GULF OF PAPAGAYO...E WINDS ARE IN THE 20 TO 25 KT RANGE.

$$
COBB