000
AXPZ20 KNHC 101001
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN AUG 10 2008

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 
0945 UTC.

...SPECIAL FEATURE...

HURRICANE HERNAN IS CENTERED NEAR 17.3N 125.7W AT 0900 UTC 
MOVING NW OR 305 DEG AT 09 KT. MAXIMUM SUSTAINED WINDS ARE 85 KT 
WITH GUSTS TO 105 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 973 
MB.  HERNAN HAS AN 20 NM WIDE EYE WITH SCATTERED STRONG 
CONVECTION NOTED WITHIN 90 NM OVER THE E SEMICIRCLE. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ELSEWHERE WITHIN 
60 NM OVER THE NW SEMICIRCLE AND WITHIN 210 NM OVER THE SE 
SEMICIRCLES. HERNAN IS FORECAST TO GRADUALLY WEAKEN TO A 
TROPICAL STORM BY 24 HOURS. SEE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADER MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS.

...TROPICAL LOWS...

.LOW PRES IS ANALYZED NEAR 14N109W AND ESTIMATED AT 1008 MB. 
SCATTERED MODERATE TO STRONG CONVECTION IS NOTED W OF THE 
CENTER...WITHIN 120 NM EITHER SIDE OF LINE FROM 16N108W TO 
13N112W. THE LOW IS FORECAST TO MOVE SLIGHTLY N OF DUE W AT 
ABOUT 10 KT WITH THE POSSIBILITY OF TROPICAL CYCLONE DEVELOPMENT.

.BROAD LOW PRES IS ANALYZED AS SURFACE LOW NEAR 13N95W AND 
ESTIMATED AT 1008 MB. SCATTERED MODERATE CONVECTION IS WEAKENING 
WITHIN 120 NM OF 12.5N92.5W. THE LOW IS FORECAST TO MOVE 
SLIGHTLY N OF DUE W AT ABOUT 10 KT.

...TROPICAL WAVES... 

TROPICAL WAVES NEAR 110W AND 90W HAVE BECOME VERY DIFFICULT TO 
LOCATE ESPECIALLY WITH THE DEVELOPMENT OF THE TROPICAL LOW 
PRESSURE AREAS MENTIONED ABOVE. THIS...THE WAVES HAVE BEEN 
DROPPED FROM THE CURRENT SURFACE ANALYSIS.

...ITCZ...

THE ITCZ AXIS IS ALONG 08N78W TO 10N102W TO 16N120W TO 13N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90 
NM EITHER SIDE OF LINE FROM 05N77W TO 11N88W. SCATTERED MODERATE 
CONVECTION IS NOTED WITHIN 150 NM OF 12N132W.

...DISCUSSION...

AN UPPER LEVEL TROUGH ALONG THE WESTERN SEABOARD OF N AMERICA IS 
GRADUALLY FILLING WITH TIME...BUT STILL EXTENDS S INTO THE 
DISCUSSION AREA ALONG 32N128W TO 23N140W. AN UPPER LEVEL 
ANTICYCLONE IS CENTERED OVER NORTHERN OLD MEXICO NEAR 31N106W 
WITH A RIDGE EXTENDING SW TO A SHARP CREST AT 15N143W. 
DIFFLUENCE UNDER THE RIDGE ENHANCED CONVECTION ALONG THE W COAST 
OF OLD MEXICO...AND IN THE AREA OF THE SURFACE LOW PRES AT 
14N109W...AND OVER HURRICANE HERNAN. THE RESULTANT DEBRIS 
MOISTURE IS OBSERVED N OF 20N BETWEEN 102W AND 115W WITH SOME 
ADVECTED NE ACROSS ARIZONA AND NEW MEXICO. DEBRIS MOISTURE IS 
ALSO INDICATED S OF 18N W OF 120W WITH SOME OF MOISTURE 
SPREADING S ACROSS THE EQUATOR AT 135W. OTHERWISE...DRY UPPER 
AIR IS INDICATED W OF A LINE ALONG 32N114W TO 20N120W TO 18N140W 
WITH SOME ENTRAINING INTO THE NW QUADRANT OF HURRICANE HERNAN. 
AT THE LOW LEVELS A RIDGE EXTENDS FROM 32N135W TO 23N113W. 
LOCALLY OVERCAST STRATOCUMULUS IS NOTED N OF 18N W OF 115W.  

AN ATLC UPPER TROUGH EXTENDS W ACROSS THE CARIBBEAN AND OLD 
MEXICO ALONG 20N INTO THE E PACIFIC TO NEAR 17N107W. AN UPPER 
RIDGE EXTENDS ROUGHLY ALONG 10N70W TO 17N90W. UPPER LEVEL NE TO 
E FLOW DOMINATES THE TROPICAL PACIFIC S OF THE ITCZ ADVECTING 
MOISTURE S OF THE EQUATOR E OF 95W.

$$
NELSON