000
AXPZ20 KNHC 222156
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JUL 22 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 16N95W TO 
12N109W TO 12N117W TO 08N128W TO 09N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WAS NOTED WITHIN 90 NM EITHER SIDE OF 
AXIS E OF 126W. 

...DISCUSSION...

A UPPER LEVEL ANTICYCLONE IS CENTERED ALONG THE W COAST OF 
MEXICO NEAR MAZATLAN AND EXTENDS A RIDGE W-SW TO NEAR 17N134W. 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 114W. JUST TO THE NW OF THE ANTICYCLONE LIES A WEAKENING 
DEEP LAYERED TROUGH...WITH UPPER LEVEL CYCLONE CENTERED OVER THE 
N CENTRAL GULF OF CALIFORNIA SHIFTING SLOWLY NE. THIS TROUGH 
WILL QUICKLY BE EXPELLED NORTHEASTWARD INTO NW MEXICO AND THE SW 
U.S. AS THE RIDGE EXPANDS. S OF THESE FEATURES...UPPER LEVEL 
EASTERLIES DOMINATE THE EPAC S OF 18N FROM CENTRAL AMERICA TO 
133W...WITH STRONG EASTERLY SHEAR TO 40 KT FROM THE W COAST OF 
MEXICO JUST W OF THE GULF OF TEHUANTEPEC WWD TO 115W. DUE TO 
THIS PREVAILING STRONG SHEAR SIGNIFICANT CONVECTION IS GENERALLY 
LIMITED TO NEAR THE ITCZ AND CELLS EXITING THE W COASTS OF THE 
CENTRAL AMERICAN NATIONS. 

A 1033 MB SURFACE HIGH PRES WAS CENTERED WELL NW OF THE 
DISCUSSION AREA NEAR 43N145W WITH A RIDGE AXIS EXTENDING THROUGH 
28N139W TO 20N110W. THE RIDGE AXIS IS MARKED BY STABLE AIR AND 
STRATOCUMULUS CLOUDS ESPECIALLY N OF 17N. A LOW LEVEL BROAD 
CYCLONIC CIRCULATION GENERALLY DOMINATES E OF 110W...FROM THE 
ITCZ TO 20N...AND EXTENDS INTO THE SW GULF OF MEXICO WHERE A 
TROPICAL DISTURBANCE IS ATTEMPTING TO BECOME BETTER ORGANIZED. 
ANTICYCLONIC FLOW PREVAILS S OF THE ITCZ AND E OF 130W...WITH SE 
TO S WINDS OF 20-25 KT DEPICTED BY AFTERNOON SCATTEROMETER 
PASSES BETWEEN 108W AND 125W. LIGHT TO MODERATE S TO SW FLOW WAS 
PRODUCING ONSHORE WINDS ACROSS THE MAJORITY OF THE CENTRAL 
AMERICAN W COASTS.

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 27N BETWEEN 122W AND 134W. THIS N SWELL 
WILL GRADUALLY SUBSIDE BELOW 8 FT BY FRI MORNING.

13-15 SECOND PERIOD CROSS EQUATORIAL S TO SW SWELL OF 6 TO 9 FT 
LIES ACROSS THE S CENTRAL PORTION OF THE FORECAST AREA GENERALLY 
S OF 10N BETWEEN 80W AND 130W. THIS SWELL WILL GRADUALLY FADE 
THROUGH SAT...WHILE A NEW SURGE OF SE SWELL MOVES 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.

$$
STRIPLING