000
AXPZ20 KNHC 061559
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON JUL 06 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...
THE SECOND TROPICAL STORM OF THE 2009 EASTERN NORTH PACIFIC 
HURRICANE SEASON...NAMED BLANCA...FORMED EARLY THIS MORNING. AT 
1500 UTC...BLANCA IS CENTERED NEAR 17.1N 111.8W OR ABOUT 420 NM 
SOUTH-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA MOVING 
W-NW AT 8 KT. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS 
TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. SEE 
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP3/WTPZ33 KNHC FOR MORE DETAILS. BLANCA IS GETTING BETTER 
ORGANIZED AS THE MORNING WEARS ON. THE FIRST FEW VISIBLE IMAGES 
INDICATE THAT THE CENTER OF THIS STORM IS EMBEDDED WITHIN WHAT 
COULD BE THE BEGINNINGS OF A CENTRAL DENSE OVERCAST. BLANCA IS 
CURRENTLY MOVING OVER 28C WATER IN A LOW SHEAR ENVIRONMENT...AND 
INTENSIFICATION IS FORECAST IN THE NEAR-TERM. HOWEVER...THE 
CYCLONE SHOULD REACH SUB-26C WATERS WITHIN 24 HOURS. AS A 
RESULT...THE FORECAST CALLS FOR INTENSIFICATION DURING THE NEXT 
24-36 HOURS...FOLLOWED BY WEAKENING.  

...TROPICAL WAVES...
TROPICAL WAVE OVER THE FAR E PORTION OF THE DISCUSSION AREA IS 
ALONG 87W N OF 2N TO THE HONDURAS/NICARAGUA BORDER MOVING W 15 
KT. A CLUSTER OF SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS NEAR 10N87W. 

TROPICAL WAVE FROM 2N-14N ALONG 103W/104W MOVING W AT 15 KT. 
ISOLATED SHOWERS ALONG THE WAVE AXIS N OF 4N.

...ITCZ...
THE ITCZ AXIS IS ALONG 08N84W TO 07N100W TO 09N120W TO 09N138W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 
04N TO 11N BETWEEN 86W AND 102W. SCATTERED MODERATE CONVECTION 
IS WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 110W AND 113W...AND 
FROM 08N TO 13N W OF 130W. 

...DISCUSSION...
A BROAD ELONGATED UPPER-LEVEL ANTICYCLONIC CIRCULATION IS 
CENTERED NEAR 28N121W WITH AN E-W RIDGE EXTENDING OVER THE NORTH 
WATERS AND NORTHERN MEXICO. THIS FEATURE SHOULD STEER BLANCA ON A
MOSTLY WEST-NORTHWESTWARD COURSE DURING THE NEXT FEW DAYS. 
ANOTHER UPPER-LEVEL HIGH ANCHORED OVER THE SW CARIBBEAN 
DOMINATES CENTRAL AMERICA AND THE FAR E PORTION OF THE 
DISCUSSION AREA...AND IS HELPING TO INDUCE SOME CONVECTION ALONG 
THE ITCZ AXIS AND NEAR THE ABOVE MENTIONED TROPICAL WAVES. 
OTHERWISE MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR AT 
THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE COVERS MOST OF THE 
AREA N OF 15N W OF 120W. FARTHER SOUTH...THERE IS AN UPPER LEVEL 
INVERTED TROUGH FROM 20N120W TO 14N126W. 

A SURFACE TROUGH IS EMBEDDED IN THE ITCZ EXTENDING FROM 13N135W 
TO 04N138W. AN INVERTED-V PATTERN IS NOTED ASSOCIATED WITH THIS 
SYSTEM ON VIS SATELLITE IMAGERY WITH SCATTERED MODERATE 
CONVECTION NEAR THE NORTHERN END OF THE TROUGH.  

A 1027 MB HIGH LOCATED NW OF AREA EXTENDS A RIDGE FROM 32N135N 
TO 20N120W. BROKEN TO OVERCAST STRATOCUMULUS CLOUDS BLANKET THE 
AREA N OF 15N W OF 120W. SCATTERED SHOWERS ARE OVER THE GULF OF 
CALIFORNIA FROM 26N TO 29N.

THE GULF OF PAPAGAYO EVENT OF NE 20 KT WINDS IS FORECAST TO 
DIMINISH IN ABOUT 18-24 HRS AS HIGH PRES OVER THE NRN CARIBBEAN 
SEA SHIFTS E.

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



$$
GR