000
AXPZ20 KNHC 301605
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI JUL 29 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 1008 MB LOW PRES 
NEAR 10N97W TO 11N110W TO 1008 MB LOW PRES NEAR 13N117W TO 
11N130W AND TO BEYOND THE AREA AT 0N140W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS S OF THE MONSOON TROUGH WITHIN 75 NM OF LINE
FROM 6N101W TO 7N108W. SIMILAR CONVECTION IS ALSO WITHIN 60 NM OF
THE MONSOON TROUGH BETWEEN 121W-130W AND W OF 132W.

...DISCUSSION...

AN UPPER LEVEL NEAR 28N129W IS BEING PICKED UP BY AN AMPLIFYING 
NORTHERN STREAM TROUGH. THE MEAN TROUGH OVER THE EASTERN NORTH 
PACIFIC IS EXPECTED TO SHIFT SLIGHTLY WESTWARD OVER THE NEXT FEW 
DAYS. TO THE W OF THR TROUGH...AN UPPER LEVEL ELONGATED ANTICYCLONE
IS NOTED W28N144W. THIS ANTICYCLONE WILL MOVE LITTLE AND WILL 
WEAKEN AS THE NORTHERN STREAM TROUGH APPROACHES. AT THE SURFACE
WEAK HIGH PRES IS IN PLACE WITH THE ASSCOIATED 1016 MB HIGH CENTER
AT 25N127W. A WEAK SURFACE TROUGH EXTENDS FROM 30N129W TO 
27N133W...WHICH HAS WEAKEANED THE RIDGE ALLOWING FOR NE 
TRADES TO CONTINUE IN THE GENTLE TO MODERATE BREEZE RANGE
OVER MUCH OF THE AREA. THE EXCEPTION LIES JUST W OF THE SURFACE 
TROUGH OVER NW WATERS WHERE THE PRES GRADIENT IS TIGHT ENOUGH TO 
SUPPORT FRESH NE WINDS. NE SWELL FROM A NEAR-GALE TO GALE WIND 
AREA OFF THE U.S. PACIFIC NW COAST ASSOCIATED WITH THE DEEP 
LAYER TROUGHING HAS MOVED INTO NW WATERS AND RAISED SIGNIFICANT 
WAVE HEIGHTS TO 9 FT. THESE CONDITIONS WILL LAST AT LEAST
THROUGH THE NEXT 24 HOURS...THEN SUBSIDE TO LESS THAN 20 KT
AND LESS THAN 8 FT BY 48 HOURS.

OVER THE SOUTHERNH SECTION OF THE AREA...A SECOND UPPER LEVEL
ANTICYCLONE IS IDENTIFIED TO BE NEAR 19N119W WITH A RIDGE 
EXTENDING WSW TO COL REGION AT 16N138W. A WEAK UPPER LOW NEAR 
26N115W IS BREAJKING UP THE RIDGE THAT RESUMES NEAR 17N108W AND 
EXTENDS NE TO AN ANTICYCLONE OVER N CENTRAL MEXICO NEAR 27N105W. 
SCATTERED MODERATE/ISOALTED STRONG CONVECTION EXISTS FROM 12N
TO 15N BETWEEN 95W AND 100W...AND ALSO WITHIN 75 NM OF A LINE
FROM 15N104W TO 19N107W. THIS CONVECTION IS BEING ENHANCED BY 
THE DIFFLUENCE ALOFT ASSOCIATED WITH THE RIDGE AXIS. THE DEEP 
LAYER TROUGH IS FOREAST TO SHIFT WESTWARD AND WEAKEN THROUGH
THE NEXT COUPLE OF DAYS.

SW MONSOON WINDS OF 20 KT ARE SEEN  FEEDING INTO LOW PRES OF
1008 MB CENTERED NEAR 10N97W. SEAS THERE ARE TO 9 FT EXCEPT WITHIN
150 NM SW QUADRANT OF LOW WHERE WINDS ARE 20-25 KT WITHN SEAS TO 
10 FT. THE GLOBAL MODEL GUIDANCE FORECASTS THE LOW TO TRACK 
IN A GENERAL W TO NW DIRECTION OVER THE NEXT 48 HOURS WITH POSSIBLE
SLOW INTENSIFICATION.

HE NEXT FEW DAYS AND THE LOW WILL TRACK UNDER A DIFFLUENT AREA 
BETWEEN 20 KT E-NE FLOW TO ITS N AND 20-40 KT N FLOW TO ITS S. 

   
$$
AGUIRRE