000
AXPZ20 KNHC 181546
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI JUN 18 2010

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 FEATURE....

AT 18/1500 UTC...TROPICAL STORM BLAS IS CENTERED AT 16.0N 107.4W 
MOVING W-NW OR 300 DEG AT 5 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH 
GUSTS TO 50 KT...WITH THE INTENSITY FORECAST CALLING FOR BLAS TO 
BECOME A TROPICAL DEPRESSION IN ABOUT 48 HR AND A REMNANT LOW IN 
ABOUT 96 HR AS IT MOVES OVER STEADILY DECREASING SEA SURFACE 
TEMPERATURES. THIS TROPICAL STORM HAS BECOME A LITTLE BETTER 
ORGANIZED...WITH THE LOW-LEVEL CENTER NEAR OR EMBEDDED IN THE 
NORTHERN SIDE OF THE CENTRAL CONVECTION. NUMEROUS STRONG 
CONVECTION IS NOTED WITHIN 120 NM S SEMICIRCLE WITH SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION WITHIN 60 NM N 
SEMICIRCLE. SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCPEP3/ WTPZ23 KNHC FOR MORE DETAILS. 

...TROPICAL WAVE...

A TROPICAL WAVE EXTENDS FROM 16N95W TO 8N97W WITH A 1010 MB LOW 
NEAR 13N96W. THIS SYSTEM IS MOVING W NEAR 10 KT. NUMEROUS 
MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM NE 
QUADRANT AND SCATTERED MODERATE CONVECTION IS WITHIN 90 SW 
QUADRANT. DEVELOPMENT OF THIS SYSTEM...IF ANY...IS EXPECTED TO 
BE SLOW.  

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 08N78W TO 
07N95W THEN RESUMES FROM 11N106W TO 10N102W TO 08N120W TO 
07N140W. SCATTERED MODERATE FROM 04N TO 06N BETWEEN 81W AND 91W. 
SIMILAR CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE OF AXIS W 
OF 132W. 

...DISCUSSION...

A WEAKENING UPPER LEVEL TROUGH EXTENDS FROM 29N120W TO 18N126W. 
A STRONGER UPPER-LEVEL TROUGH IS APPROACHING THE FAR NW CORNER 
OF THE FORECAST AREA AND EXTENDS SW TO THE HAWAIIAN ISLANDS. A 
SMALL MID/UPPER LEVEL ANTICYCLONE IS NEAR 16N124W WITH A RIDGE 
SW TO 8N132W. A SECOND UPPER LEVEL ANTICYCLONE IS CENTERED OVER 
SOUTH TEXAS EXTENDING A RIDGE SW TO NEAR TROPICAL STORM BLAS. 
MOST OF THE GLOBAL MODELS BUILD THIS RIDGE TO THE NORTH OF THE 
CYCLONE...A PATTERN WHICH WILL FAVOR A WEST-NORTHWEST TO WEST 
MOTION WITH A SLIGHT INCREASE IN FORWARD SPEED. ANOTHER 
ANTICYCLONE IS W OF THE AREA AT 12N148W WITH A RIDGE NE TO NEAR 
21N134W. MID TO UPPER LEVEL MOISTURE IS SPREADING INTO THE NW 
CORNER OF THE AREA ALONG THE NW PERIPHERY OF THIS RIDGE. 
OTHERWISE...THE UPPER LEVELS ARE DRY W OF A LINE FROM 26N109W TO 
10N130W WHILE ABUNDANT MID/UPPER LEVEL MOISTURE IS NOTED E OF 
THE SAME LINE...WHICH INCLUDES CONVECTION ASSOCIATED WITH T.S. 
BLAS...THE REMNANTS OF TD-3E AND A TROPICAL LOW AT 13.5N95W. 

AT THE SURFACE...HIGH PRES COVERS THE AREA N OF 17N AND W OF 
ABOUT 120W. WINDS ARE EXPECTED TO INCREASE TO 20 KT E OF THIS 
RIDGE TO ALONG THE W COAST OF THE NORTHERN BAJA PENINSULA IN 
ABOUT 24 HOURS. NE TRADES OF 20 KT S OF THE RIDGE...FROM 9N TO 
12N W OF ABOUT 134W ARE EXPECTED TO ONLY SHRINK VERY LITTLE IN 
COVERAGE THROUGH THE NEXT 48 HRS.

CROSS EQUATORIAL SOUTHERLY SWELLS ARE RESULTING IN SEAS TO 10 FT 
S OF 07N BETWEEN 80W AND 88W. SOME SLIGHT DECREASE IN SEAS ARE 
EXPECTED ACROSS THIS AREA THROUGH THE NEXT 48 HRS.
 
$$
GR