000
AXPZ20 KNHC 062146
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT AUG 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH FROM 10N85W TO 08N106W TO 08N114W THEN ITCZ TO 
09N118W TO 13N124W THEN BREAKS AND RESUMES FROM 13N135W TO 
12N140W. SCATTERED MODERATE WITHIN 120 NM S OF AXIS BETWEEN 92W 
AND 96W. SCATTERED MODERATE WITHIN 90 NM EITHER SIDE OF AXIS 
BETWEEN 104W AND 110W. SCATTERED MODERATE WITHIN 120 NM N OF 
AXIS BETWEEN 113W AND 117W. 

...DISCUSSION...

AN UPPER LEVEL RIDGE EXTENDS FROM THE SOUTHERN GREAT PLAINS OF 
THE CONUS WSW ACROSS EXTREME NORTHERN MEXICO...NORTHERN BAJA
CALIFORNIA PENINSULA THROUGH 26N130W THEN TURNS SWD TO A COL 
NEAR 13N138W. THE NOW REMNANT LOW OF FORMER TROPICAL STORM 
EUGENE CONTINUES TO MOVE W AROUND THE SOUTHERN PERIPHERY OF THIS 
UPPER RIDGE...SEE SURFACE FEATURES BELOW FOR ADDITIONAL DETAILS 
ON THIS FEATURE. AN UPPER LEVEL TROUGH CLIPPING THE FAR NW 
CORNER OF THE AREA EXTENDS FROM A DEVELOPING CYCLONIC 
CIRCULATION NW OF THE AREA NEAR 31N148W TO JUST NE OF THE 
HAWAIIAN ISLANDS. THIS TROUGH WILL REMAIN BLOCKED BY THE RIDGE 
DURING THE NEXT 24-48 HOURS. VERY DRY AIR UNDER MODERATE TO 
STRONG SUBSIDENCE IS NOTED BY WATER VAPOR SATELLITE IMAGERY N OF 
12N W OF 130W AND N OF 24N W OF THE BAJA CALIFORNIA PENINSULA. 
OTHERWISE...PRIMARILY EASTERLY UPPER LEVEL WINDS DOMINATE THE 
REMAINDER OF THE DISCUSSION AREA ALOFT WITH MID TO UPPER LEVEL 
TROPICAL MOISTURE BEING ADVECTED WESTWARD S OF 24N TO ALONG 
130W. 

AT THE SURFACE...1035 MB HIGH PRES IS CENTERED WELL NW OF THE 
FORECAST AREA NEAR 40N150W WITH AN ASSOCIATED RIDGE EXTENDING SE 
TO 25N118W. THE PRES GRADIENT BETWEEN THE RIDGE AND THE REMNANT 
LOW OF EUGENE IS RESULTING IN A LARGE SWATH OF NE WINDS OF 20-25 
KT IN AN AREA FROM 19N TO 26N W OF 125W. A 1754 UTC ASCAT PASS 
CAPTURED THE CIRCULATION OF THE REMNANT LOW DEPICTING AN AREA OF
25-30 KT WINDS WITHIN 150 NM OF THE CENTER IN THE N SEMICIRCLE 
WITH ISOLATED WINDS APPROACHING GALE FORCE. FOR ADDITIONAL 
INFORMATION REFER TO THE HIGH SEAS UNDER AWIPS/WMO HEADERS 
MIAHSFEP2/FZPN03 KNHC. VISIBLE AND INFRARED SATELLITE IMAGERY 
INDICATES THAT SOME LOW TOPPED CONVECTION HAS REDEVELOPED AROUND 
THE LOW LEVEL CIRCULATION CENTER. THIS CONVECTION SHOULD 
DISSIPATE AS THE REMNANT LOW CONTINUES TO MOVE WESTWARD OVER 
INCREASINGLY COLDER WATERS. 

A RATHER TIGHT PRES GRADIENT BETWEEN THE RIDGE NOTED ABOVE AND 
LOWER PRESSURES OVER BAJA CALIFORNIA IS RESULTING IN 20 KT 
NORTHERLY WINDS N OF 28N WITHIN 120 NM W OF THE COAST OF BAJA 
CALIFORNIA AS CAPTURED BY THE EDGE OF A 1752 UTC ASCAT PASS.
THESE WINDS ARE FORECAST TO DIMINISH TO LESS THAN 20 KT IN 24 
HOURS AS THE PRES GRADIENT WEAKENS.

THE WEAK AREA OF LOW PRES CENTERED NEAR 19N110W HAS DEGENERATED 
INTO A SURFACE TROUGH ALONG 120W FROM 16N TO 21N. THIS TROUGH IS 
EXPECTED TO DISSIPATE WITHIN THE NEXT 24 HOURS.

CROSS-EQUATORIAL SOUTHERLY SWELL CONTINUES TO PROPAGATE ACROSS 
THE REGIONAL WATERS MAINLY S OF 10N AND W OF 95W BUILDING SEAS 
TO 10 FT. THIS SWELL WILL GRADUALLY DECAY AND BECOME CONFINED TO 
W OF 100W IN 24 HOURS...THEN TO W OF 105W IN 48 HOURS.

$$
COBB