000
AXPZ20 KNHC 230326
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI JUL 23 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0145 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 09N84W TO 
09N92W TO 08N97W...THEN RESUMED FROM 10N98W TO 11N112W TO 
10N121W TO 07N130W TO 08N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WAS NOTED WITHIN 90 NM EITHER SIDE OF AXIS E 
OF 96W...AND WITHIN 120 NM EITHER SIDE OF AXIS BETWEEN 105W AND 
134W. 

...DISCUSSION...

A UPPER LEVEL ANTICYCLONE IS CENTERED ALONG THE W COAST OF 
MEXICO JUST E OF MAZATLAN...AND EXTENDS N IN A NARROW RIDGE 
ACROSS THE SIERRA MADRES...AND ALSO W-SW FORMING A BROADER RIDGE 
S OF 26N TO NEAR 18N136W. A NARROW AND ELONGATED MID TO UPPER 
TROUGH LIES OVER FAR NW WATERS FROM 30N134W TO 14N141W...AND IS 
SANDWICHED BETWEEN THE FORMER RIDGE AND A SECOND UPPER LEVEL 
ANTICYCLONE NE OF THE HAWAIIAN ISLANDS. THE EASTERN 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 113W. JUST TO THE NW OF THE 
ANTICYCLONE OVER MEXICO LIES A WEAKENING DEEP LAYERED 
TROUGH...WITH MID LEVEL CYCLONE CENTERED OVER THE N CENTRAL GULF 
OF CALIFORNIA SHIFTING N-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. 

A 1033 MB SURFACE HIGH PRES WAS CENTERED WELL NW OF THE 
DISCUSSION AREA NEAR 43N144W WITH A RIDGE AXIS EXTENDING THROUGH 
28N139W TO 21N118W. 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 PERSISTS. 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 NEAR 8 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 EARLY 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