000
AXPZ20 KNHC 220314
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU JUL 22 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 
0130 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 16N98W TO 
13N110W TO 07N123W TO 10N140W. SCATTERED MODERATE CONVECTION WAS 
NOTED WITHIN 120 NM EITHER SIDE OF AXIS E OF 129W. 

...DISCUSSION...

AN UPPER LEVEL RIDGE EXTENDED ACROSS FAR W PORTIONS OF THE 
AREA...FROM A CENTER LOCATED SE OF THE BIG ISLAND OF HAWAII NE 
TO NEAR 27N137W. A SECOND HIGH WAS CENTERED OVER THE SUB TROPICS 
NEAR 21N119W. A NARROW AND ELONGATED MID TO UPPER TROUGH 
SEPARATED THESE TWO HIGHS...EXTENDING INTO THE AREA FROM A 
FILLING UPPER LOW NEAR 30.5N126W TO A MID LEVEL LOW NEAR 
19N136W. STABLE ATMOSPHERIC CONDITIONS PREVAILED ACROSS MOST OF 
THIS AREA...EXCEPT NEAR THE SOUTHERN LOW PRESSURE ALOFT...WHERE 
SHALLOW STRATIFORM PRECIP WAS OCCURRING. TO THE NE OF THE 
EASTERNMOST HIGH WAS A SOMEWHAT ELONGATED DEEP LAYERED CYCLONE 
CENTERED JUST OFF THE W COAST OF BAJA CALIFORNIA...WITH THE 
CIRCULATION ABOUT 360 NM WIDE AND ENCOMPASSING ALL OF BAJA AND 
THE GULF OF CALIFORNIA. THE PARENT UPPER CYCLONE IS FORECAST TO 
LIFT N DURING THE NEXT 36 HOURS...AND CONSOLIDATE WITH THE N 
PORTION OF PREVIOUS ELONGATED TROUGH ACROSS SRN CALIFORNIA AND 
ARIZONA....WHILE THE SOUTHERN PORTION OF THE ELONGATED TROUGH 
WILL CONTINUE TO DRIFT W. THIS FRACTURED TROUGH IS EXPECTED TO 
BECOME INVIGORATED AS UPSTREAM ENERGY DROPS INTO THE BACKSIDE OF 
THE TROUGH AND ENHANCES IT BETWEEN 135W AND 140W. RIDGING TO THE 
E WILL EXPAND SOMEWHAT W TO E. 

E AND SE OF THESE FEATURES...UPPER LEVEL EASTERLIES PREVAIL AND 
ARE PRODUCING A SHEARED ENVIRONMENT THAT IS ENHANCING CONVECTION 
NEAR THE ITCZ AND ACROSS THE FAR TROPICAL EPAC N TO THE SW COAST 
OF MEXICO AND CENTRAL AMERICA. AS THE HIGH TO THE N EXPANDS W 
DURING THE NEXT FEW DAYS...THIS BROADENING UPPER ELY JET WILL 
SPREAD W ACROSS THE TROPICS AND REACH TO NEAR 130W BY FRI 
EVENING WITH CORE SPEEDS ALOFT FORECAST TO 55 KT. 

A 1034 MB HIGH PRES AT THE SURFACE IS CENTERED WELL NW OF THE 
DISCUSSION AREA NEAR 45N148W WITH A RIDGE AXIS EXTENDING THROUGH 
30N131W TO 18N114W. THE RIDGE AXIS IS MARKED BY STABLE AIR AND 
STRATOCUMULUS...ESPECIALLY N OF 17N. ANTICYCLONIC FLOW DOMINATED 
THE FAR EPAC S OF THE ITCZ EXTENDING W TO 125W WITH SELY WINDS 
TO 20 KT EXPECTED TO EXPAND ACROSS THIS ZONE IN THE NEXT 48 
HOURS. 

GALE FORCE WINDS ALONG THE PACIFIC NW COAST OF THE U.S. CONTINUE 
TO GENERATE NORTHERLY SWELL IN THE 8 TO 11 FT RANGE OVER
THE DISCUSSION AREA N OF 24N BETWEEN 119W AND 135W. THIS SWELL 
WILL GRADUALLY SUBSIDE TO 8 FT THU NIGHT AND BELOW 8 FT BY FRI 
MORNING.

LONG PERIOD CROSS EQUATORIAL SOUTHERLY SWELL OF 8 TO 9 FT LIES 
ACROSS THE S CENTRAL PORTION OF THE FORECAST AREA GENERALLY S OF 
10N BETWEEN 95W AND 130W. THIS SWELL WILL GRADUALLY DECAY OVER 
THE NEXT TWO DAYS...BUT A NEW SURGE OF SE SWELL IS EXPECTED TO 
MOVE ACROSS THE EQUATOR THU NIGHT. IN ADDITION...SE TO S WINDS 
ARE EXPECTED TO INCREASE TO 20 KT TONIGHT THROUGH FRI IN S 
CENTRAL WATERS. THIS WILL HELP KEEP SEAS ABOVE 8 FT IN MUCH OF 
THE REGION S OF 10N THROUGH FRI MORNING.

$$
STRIPLING