000
AXPZ20 KNHC 070921
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUL 07 2009

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 
0900 UTC.

...SPECIAL FEATURE...
TROPICAL STORM BLANCA CENTERED NEAR 18.5N 114.5W AT 0900 UTC OR 
370 MILES SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MOVING WNW 
OR 295 DEG AT 8 KT. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH 
GUSTS TO 55 KT. MINIMUM PRESSURE IS 998 MB. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ33 KNHC 
FOR MORE DETAILS. THE DEEP CONVECTION AROUND THE CENTER OF 
BLANCA HAS DECREASED SOME OVER THE PAST FEW HOURS HOWEVER THE 
BANDING STRUCTURE REMAINS WELL DEFINED. A SMALL AREA OF MODERATE 
TO STRONG CONVECTION HAS DEVELOPED NEAR THE CENTER OTHERWISE 
NUMEROUS MODERATE TO STRONG CONVECTION IS FROM 14N-20N BETWEEN 
110W-116W. BLANCA IS FORECAST TO MOVE OVER COOLER WATERS AND AS 
A RESULT THE FORECAST CALLS FOR THE STORM TO REMAIN AT 45 KT 
THROUGH TODAY THEN FOLLOWED WEAKENING THEREAFTER THROUGH THE 
REST OF THE WEEK.

...TROPICAL WAVES...
TROPICAL WAVE FROM 2N-13N ALONG 90W MOVING W 10-15 KT. ISOLATED 
CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE WAVE N OF 6N.

TROPICAL WAVE FROM 2N-13N ALONG 109W MOVING W AT 15 KT. NO 
SIGNIFICANT CONVECTION ASSOICATED WITH THE WAVE.

...ITCZ...
AXIS IS ALONG 7N78W 10N95W 8N115W 9N140W. SCATTERED STRONG 
CONVECTION N OF AXIS E OF 80W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 100 NM S OF AXIS FROM 89W-92W AND 120 
NM S OF AXIS FROM 98W-101W AND WITHIN 180W NM N OF AXIS FROM 
135W-140W.

...DISCUSSION...
A BROAD ELONGATED UPPER-LEVEL ANTICYCLONIC CIRCULATION IS 
CENTERED NEAR 28N121W WITH RIDGE EXTENDING E OVER BAJA 
CALIFORNIA AND ACROSS NORTHERN MEXICO. ANOTHER RIDGE EXTENDS W 
OF THE ANTICYCLONIC CIRCULATION TO 26N130W 20N140W. THIS FEATURE 
SHOULD STEER BLANCA ON A MOSTLY WNW COURSE DURING THE NEXT FEW 
DAYS. STRONG SUBSIDENCE WITH DRY STABLE AIR AT THE MIDDLE AND 
UPPER LEVEL OF THE ATMOSPHERE COVERS THE AREA N OF 15N W OF 120W
EXCEPT FROM AN AREA OF HIGH LEVEL MOISTURE 150 NM WIDE FROM 
23N120W TO 22N130W. S OF THE RIDGE AN UPPER LEVEL INVERTED 
TROUGH WITH AXIS FROM 25N126W TO A CYCLONIC CIRCULATION NEAR 
17N129W TO 6N140W. ANOTHER CYCLONIC CIRCULATION IS ALONG THE 
COAST OF MEXICO NEAR 16N101W. UPPER LEVEL DIFFLUENT FLOW
BETWEEN THE CYCLONIC CIRCULATION AND AN ANTICYLONIC OVER THE SW 
CARIBBEAN IS ENHANCING CONVECTIVE ACTIVITY ALON THE ITCZ E OF 
100W.

SURFACE TROUGH ANALYZED ALONG THE ITCZ OVER THE FAR W PORTION OF 
THE DISCUSSION AREA FROM 6N140W TO 13N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS WITHIN 300 NM W OF THE TROUGH.  

SURFACE RIDGE EXTENDS FROM 32N135N TO 25N110W. BROKEN TO 
OVERCAST STRATOCUMULUS CLOUDS BLANKET THE AREA N OF 15N W OF 
120W.

LARGE SWELL FROM THE SOUTHERN HEMISPHERE CONTINUES TO CROSS THE 
EQUATOR OVER THE S PORTION OF THE DISCUSSION AREA

$$
DGS