000
AXPZ20 KNHC 201551
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN JUN 20 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 FEATURES....

AT 20/1500 UTC...TROPICAL STORM BLAS IS CENTERED AT 17.6N 113.4W 
MOVING W-NW OR 285 DEG AT 10 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 1001 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH 
GUSTS TO 50 KT. SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCPEP3/WTPZ23 KNHC FOR MORE DETAILS. DEEP CONVECTION 
HAS INCREASED NEAR THE CENTER OF CELIA DURING THE LAST COUPLE OF 
HOURS. THERE ARE SOME HINTS OF A EYE BEGINNING TO FORM WITHIN 
THE CDO. THE FORECAST SHOWS A GRADUAL INTENSIFICATION TO A PEAK 
OF NEAR 100 KT IN 3 OR 4 DAYS. SOME WEAKENING IS INDICATED 
THEREAFTER.
 
AT 20/1500 UTC...TROPICAL STORM CELIA IS CENTERED AT 11.9N 
100.0W MOVING W OR 260 DEG AT 6 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 994 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH 
GUSTS TO 65 KT. SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCPEP4/WTPZ24 KNHC FOR MORE DETAILS. BLAS HAS A SMALL 
CLUSTER OF DEEP CONVECTION NEAR AND TO THE SOUTHWEST OF THE 
CENTER BUT THERE ARE NO BANDING FEATURES. ALTHOUGH THE 
NORTHEASTERLY SHEAR OVER THE SYSTEM IS EXPECTED TO DECREASE 
SOMEWHAT...THE STORM IS MOVING OVER PROGRESSIVELY COOLER WATERS 
AND INTO AN INCREASINGLY STABLE AIR MASS. THE INTENSITY FORECAST 
CALLS FOR BLAS TO WEAKEN TO A TROPICAL DEPRESSION IN ABOUT 24 
HOURS AND THEN BE REDUCED TO A POST-TROPICAL REMNANT LOW.

...TROPICAL WAVE...

A TROPICAL WAVE EXTENDS FROM 15N85W TO 7N86W MOVING W 15 KT. THE 
WAVE IS ON THE FAR EAST SIDE OF THE LARGE CYCLONIC GYRE THAT 
PREVAILS ACROSS THE EASTERN PORTION OF THE AREA. CONVECTION 
IMMEDIATELY TIED TO THE WAVE HAS DIMINISHED AND ONLY SCATTERED 
MODERATE CONVECTION IS NOTED NEAR 9N86W. 

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 08N87W TO 
05N97W THEN RESUMES AT 11N108W TO 08N116W TO 07N128W TO 07N140W. 
NUMEROUS MODERATE ISOLATED STRONG FROM 06N TO 09N BETWEEN 86W 
AND 94W. SCATTERED MODERATE WITHIN 60 NM EITHER SIDE OF AXIS 
BETWEEN 110W AND 122W.

...DISCUSSION...

AN UPPER LEVEL TROUGH IS CLIPPING THE FAR NE SECTION OF THE AREA 
WHILE AN UPPER LEVEL ANTICYCLONE IS NOTED NEAR 22N128W WITH A 
RIDGE NE TO 25N115W...AND ANOTHER SW TO 16N138W. A MOISTURE 
PLUME IS SPREADING INTO THE FAR NW CORNER OF THE AREA. PART OF 
IT IS ALREADY REACHING NORTHEASTWARD TO ACROSS FAR SOUTHERN 
CALIFORNIA AND NORTHERN BAJA. OTHERWISE...SATELLITE WATER VAPOR 
IMAGERY DEPICTS ABUNDANT MODERATE SUBSIDENCE LEADING TO STABLE 
ENVIRONMENTAL CONDITIONS OVER MUCH OF THE REGION W OF LINE 
27N110W TO 12N123W.

A MID/UPPER LEVEL ANTICYCLONE IS CENTERED OVER S TEXAS WITH A 
RIDGE ACROSS SOUTHERN BAJA CALIFORNIA PENINSULA TO JUST N OF 
TROPICAL STORM BLAS. UPPER LEVEL EASTERLY FLOW TO THE S OF THE 
RIDGE CONTINUES TO IMPACT TROPICAL STORM BLAS. CURRENTLY...15 KT 
OF EASTERLY SHEAR IS ALSO SEEN OVER CELIA. 

AT THE SURFACE...A 1033 MB HIGH LOCATED NW OF AREA EXTENDS A 
RIDGE SE COVERING ROUGHLY THE AREA N OF 15N W OF 120W. THE PRES 
GRADIENT BETWEEN THIS RIDGE AND LOWER PRES OVER THE SW CONUS IS 
RESULTING IN NW TO N WINDS OF 20 KT N OF 26N BETWEEN 118W AND 
126W. THE PRES GRADIENT WILL TIGHTEN BETWEEN BLAS AND THIS 
RIDGE OVER THE NEXT 48 HRS ALLOWING FOR WINDS TO INCREASE TO 20 
AND SEAS TO BUILD TO 9 FT IN A LARGE AREA...PARTICULARLY TO THE 
NW OF BLAS. TRADE WINDS REMAIN CONFINED FROM 10N TO 15N W OF 
134W.

CROSS EQUATORIAL SOUTHERLY SWELLS ARE RESULTING IN SEAS TO 8 FT 
OVER THE SE AND CENTRAL REGION. WINDS ARE FORECAST TO INCREASE 
TO 20 KT IN ABOUT 24 HOURS OVER THE SE BUT COULD BE SLIGHTER 
HIGHER NEAR DEEP CONVECTION IN THE VICINITY OF THE TROPICAL WAVE 
AND THE ITCZ.
 
$$
GR