000
AXPZ20 KNHC 291605
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...

MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 1008 MB LOWS AT
10N93W AND 9N100W. IT THEN CONTINUES NW TO 11N110W TO A 1009 MB
LOW AT 12N116W AND TO 11N128W...WHERE LOW LEVEL WINDS INDICATE
THAT IT TRANSITIONS TO THE ITCZ AXIS TO BEYOND THE AREA AT
9N140W. SCATTERED STRONG CONVECTION IS WITHIN 180 NM S OF THE
MONSOON TROUGH BETWEEN 85W-88W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 60 NM OF THE MONSOON TROUGH BETWEEN 
121W-124W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S 
OF THE MONSOON TROUGH BETWEEN 95W-104W.

...DISCUSSION...

AN UPPER LEVEL RIDGE EXTENDS FROM THE CENTRAL U.S. SW TO ACROSS
NORTHERN BAJA CALIFORNIA. AN ELONGATED UPPER LEVEL LOW MOVING ENE
IS W OF THE RIDGE NEAR 26N130W. THIS LOW HAS CUT OFF FROM AN UPPER
LEVEL TROUGH JUST N OF THE AREA ALONG 126W. THE LOW IS FORECAST
TO BE PICKED UP BY AN AMPLIFYING NORTHERN STREAM THIS EVENING 
ALLOWING FOR THE UPPER FLOW JUST N OF THE AREA TO BEGIN TO ACQUIRE
MORE OF ZONAL PATTERN OVER THE NEXT COUPLE OF DAYS. TO THE W OF 
THE LOW...THE UPPER FLOW BECOMES BROADLY ANTICLONIC WITH THE
ASSCOIATED NEARLY STATIONARY UPPER ANTICYCLONE W OF THE AREA AT 
30N144W. WATER VAPOR IMAGERY SHOWS EXTENSIVE MODERATE SUBSIDENCE
...AND ASSOCIATED DRY AIR ALOFT COVERING THE AREA N OF 18N 
KEEPING STABLE ATMOSPHERIC CONDITIONS AT THE SURFACE WHICH NOTED 
AS MOSTLY OVERCAST STRATOCUMLUS CLOUDS N OF 16N AND W OF 115W.
 
OVER THE TROPICAL SECTION OF THE DISCUSSION AREA...AN UPPER ANTICYCLONE
IS LOCATED NEAR 18N120W WITH A RIDGE SW TO 15N135W...AND ANOTHER RIDGE
ESE TO NEAR 17N110W. TO THE NE OF THE RIDGE...A SMALL UPPER 
LEVEL LOW IS NEAR 22N112W. THE LOW IS ACTING TO SEPARATE THE 
THE RIDGE PREVIOUSLY MENTIONED ABOVE ALLOWING FOR THE THE OTHER
PORTION OF THE RIDGE TO EXTEND NE TO SW FROM NORTHEASTERN MEXICO
TO WESTERN MEXICO AT 19N105W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION MOVING WESTWARD ARE ALONG AND OFFSHORE THE 
MEXICAN COAST N OF 15N BETWEEN 102W-104W. THIS ACTIVUTY IS BEING 
ENHANCED BY THE DIFFLUENCE ALOFT ASSOCIATED WITH THE RIDGE AXIS. 
THE LOW NEAR 22N112W IS FORECAST TO MOVE WNW THROUGH THE NEXT 48 HOURS
AS THE UPPER FLOW N OF THE AREA BECOMES MORE ZONAL WITH TIME. AT 
THE SAME TIME...THE RIDGE WILL THEN STRENGTHEN. 

NE SWELLS FROM A GALE AREA OFF THE U.S. PACIFIC NW COAST 
ASSOCIATED WITH THE PRES GRADINET INDUCED BY THE UPPER TROUGH N 
OF THE AREA WILL BEGIN TO MOVE INTO THE FAR NORTHERN WATERS
N OF 29N AND W OF 130W THIS AFTERNOON WITH SEAS TO 9 FT WITH
NE WINDS OF 20 KT...AND DIMINISHING TO LESS 20 KT IN 48 HOURS
WITH LINGERING SEAS UP TO 9 FT IN A NE SWELL.

MONSON SW FLOW OF 20 KT IS NOTED FROM 5N-9N BETWEEN 82W-85W
WITH SEAS TO 9 FT. A COUPLE OF WEAK 1008 MB LOWS AR ALONG THE
TROUGH NEAR 10N93W AND 10N100W. GLOBAL MODELS STILL LIKE TO HANG
ON TO THESE LOWS FOR THE MOST PART OVER THE NEXT 48 HOURS...
BUT ARE NOT TOO DEFINITIVE ON WHICH LOW MAY EVENTUALLY DEVELOP
FURTHER. A 1009 MB LOW IS NEAR 12N116W WITH SCATTERED STRONG CONVECTION
AND WINDS OF 20 KT WITHIN 150 NM IN THE NW QUADRANT. IT SHOULD SLOWLY
WEAKEN OVER THE NEXT 48 HOURS.
  
$$
AGUIRRE