000
AXPZ20 KNHC 221511
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JUL 22 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 
1300 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 14N92W TO 
10N102W TO 10N112W TO 07N128W TO 09N140W. SCATTERED MODERATE 
CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 
95W AND 100W...WITHIN 90 NM N OF THE ITCZ AXIS BETWEEN 102W AND 
105W...AND WITHIN 45 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 
122W AND 125W.

...DISCUSSION...

A UPPER LEVEL ANTICYCLONE IS CENTERED NEAR THE SOUTHERN TIP OF 
BAJA CALIFORNIA AND EXTENDS A RIDGE FROM THE CENTER NEAR 23N110W 
SW TO 16N135W. A NARROW AND ELONGATED MID TO UPPER TROUGH LIES 
OVER FAR NW WATERS FROM 30N133W TO 14N140W. THE RIDGE IS 
EXPECTED TO EXPAND W OVER THE NEXT FEW DAYS AS THE NORTH PORTION 
OF THIS TROUGH BECOMES ABSORBED INTO A NEGATIVELY TILTED MID 
LATITUDE TROUGH N OF THE AREA AND THE SOUTHERN PORTION MOVES W 
OF THE AREA. DRY STABLE UPPER LEVEL CONDITIONS PREVAIL ACROSS 
MOST OF THE AREA N OF 15N W OF 115W. JUST TO THE NW OF THE 
ANTICYCLONE LIES A WEAK UPPER TROUGH CENTERED NEAR THE W COAST 
OF BAJA CALIFORNIA ALONG 114W N OF 21N. THIS TROUGH WILL QUICKLY 
BE EXPELLED NORTHEASTWARD INTO NW MEXICO AND THE SW U.S. AS THE 
RIDGE EXPANDS. UPPER LEVEL DIFFLUENCE BETWEEN THE ANTICYCLONE 
AND 25-50 KT EAST-NORTHEASTERLY WINDS E OF A LINE FROM 18N102W 
TO 00N116W HAS ENHANCED THE SCATTERED MODERATE CONVECTION FOUND 
WITHIN 75 NM OF MEXICAN COAST FROM 19N TO 23N. THE STRONG 
EASTERLY SHEAR TO THE S IS INHIBITING CONVECTION OVER SE WATERS 
AS WELL AS OVER CENTRAL AMERICA S OF HONDURAS.

A 1036 MB SURFACE HIGH PRES IS CENTERED WELL NW OF THE 
DISCUSSION AREA NEAR 44N149W WITH A RIDGE AXIS EXTENDING THROUGH 
28N139W TO 20N117W. THE RIDGE AXIS IS MARKED BY STABLE AIR AND 
STRATOCUMULUS CLOUDS ESPECIALLY N OF 17N.

GALE FORCE WINDS ALONG THE PACIFIC NW COAST OF THE U.S. CONTINUE 
TO GENERATE NORTHERLY SWELL IN THE 8 TO 10 FT OVER THE 
DISCUSSION AREA N OF 26N BETWEEN 122W AND 134W. THIS N SWELL 
WILL GRADUALLY SUBSIDE BELOW 8 FT BY FRI MORNING.

13-15 SECOND PERIOD CROSS EQUATORIAL SOUTHERLY SWELL OF 8 TO 10 
FT LIES ACROSS THE S CENTRAL PORTION OF THE FORECAST AREA 
GENERALLY S OF 10N BETWEEN 95W AND 130W. THIS SWELL WILL 
GRADUALLY DECAY THROUGH FRI JUST AS A NEW SURGE OF SE SWELL IS 
EXPECTED TO MOVE ACROSS THE EQUATOR. THE SE SWELL WILL ALSO 
BRING SEAS TO 9 FT IN SE WATERS E OF THE GALAPAGOS ISLANDS AND S 
OF 05N FRI AND SAT. IN ADDITION...SE TO S WINDS TO 20 KT ARE 
EXPECTED TO CONTINUE TODAY THROUGH SAT IN S CENTRAL WATERS WHERE 
SEAS SHOULD REMAIN IN THE 8-10 FT RANGE S OF 10N THROUGH SAT.

$$
SCHAUER