000
AXPZ20 KNHC 300231
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE OCT 30 2012

CORRECTED TO INCLUDE MENTION OF ASCAT WINDS ASSOCIATED WITH 
SPECIAL FEATURE LOW UNDER DISCUSSION SECTION

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...SPECIAL FEATURE...

A 1006 MB LOW PRES LOCATED NEAR 14N115W IS EMBEDDED WITHIN THE 
MONSOON TROUGH. THE LOW REMAINS DISORGANIZED AS EVIDENT IN 
VISIBLE SATELLITE IMAGERY WHERE LOW LEVEL CLOUDS ARE SEEN RACING 
WESTWARD AWAY FROM IT. ASSOCIATED CONVECTION REMAINS DISORGANIZED
...AND IS OBSERVED AS THE SCATTERED STRONG TYPE INTENSITY WITHIN
150 NM OF THE CENTER IN THE SE QUADRANT. ALTHOUGH THE LOW 
CONTINUES TO BE JUST S OF OF AN UPPER LEVEL RIDGE...THE UPPER 
LEVEL SW-W WINDS ACROSS THE RIDGE HAVE INCREASED ENOUGH TO 
DISRUPT IT FROM ORGANIZING ANY FURTHER. THIS SYSTEM WILL 
CONTINUE TO HAVE A MEDIUM CHANCE OF INTENSIFYING INTO A TROPICAL 
CYCLONE WITHIN THE NEXT 48 HRS AS IT REACHES TO NEAR 16N117W 
1006 MB BY 24 HRS AND TO NEAR 16N120W 1007 MB IN 48 HRS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM NW COLOMBIA SW TO LOW PRES AT 06N78W 
1008 MB...AND CONTINUES NW TO ALONG THE COASTS OF NW PANAMA AND 
SE COSTA RICA TO 08N91W TO 13N101W TO LOW PRES AT 13N107W 1009 
MB TO LOW PRES AT 14N115W 1006 MB TO LOW PRES AT 11N122W 1008 MB 
TO 09N135W WHERE IT TRANSITIONS TO THE MONSOON TROUGH TO 
08N140W. SCATTERED MODERATE/ISOLATED STRONG WITHIN 120 NM N OF 
TROUGH BETWEEN 122W AND 128W. SCATTERED MODERATE CONVECTION IS
WITHIN 120 NM S OF TROUGH BETWEEN 89W AND 91W.

...DISCUSSION...

ALOFT...AN UPPER TROUGH EXTENDS FROM NORTHERN MEXICO WSW TO 
CENTRAL BAJA CALIFORNIA. W OF IT...BROAD MID/UPPER LEVEL 
ANTICYCLONIC FLOW IS PRESENT EXCEPT JUST NW OF THE REGION WHERE
A VERY SHARP SHORTWAVE TROUGH IS PRESSING EASTWARD TOWARDS
THE AREA. ELSEWHERE BROAD MID/UPPER LEVEL CONTINUES OVER THE 
MAJORITY OF THE DISCUSSION AREA ASSOCIATED WITH A MID/UPPER 
LEVEL ANTICYCLONE AT 11N119W. A DIFFLUENT PATTERN TO THE SW OF 
THE ANTICYCLONE IS HELPING TO FLARE UP THE CONVECTION ASSOCIATED 
WITH THE LOW PRES UNDER SPECIAL FEATURE AS WELL AS WITH THE 
OTHER LOWS DESCRIBED UNDER ITCZ/MONSOON TROUGH. SATELLITE WATER 
VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE WITH A RESULTANT VERY 
DRY AND STABLE AIR MASS OVER MOST OF THE NORTHERN PORTIONS OF 
THE AREA N OF ABOUT 19N. THE LAST AVAILABLE VISIBLE IMAGERY
FROM MON REVEALED BROKEN TO OVERCAST PATCHES OF STRATOCUMULUS 
CLOUDS MOVING WSW WITH POSSIBLE ISOLATED SHOWERS TO THE N OF 19N 
AND W OF 123W.

AT THE SURFACE...A 1022 MB HIGH PRES CENTER IS ANALYZED AT 
33N131 WITH A RIDGE EXTENDING SE TO NEAR 23N119W. HIGH PRES 
COVERS THE AREA N OF 21N W OF 122W. NE TRADE WINDS ARE RATHER 
LIGHT TO THE S AND SW OF THE RIDGE WITH SPEEDS OF 10-15 KT 
ACCORDING TO THE 1748 UTC ASCAT PASS FROM YESTERDAY. HOWEVER
...SEAS TO 9 FT IN NW SWELLS STILL LINGER OVER THE AREA FROM 
10N-19N W OF 126W. THE SAME ASCAT PASS REVEALED NE-E WINDS OF 
20-30 KT WITHIN 180 NM OF THE SPECIAL FEATURE LOW IN THE NE 
QUADRANT...AND 20-25 KT WINDS WITHIN 240 NM OF THE LOW IN THE
SE QUADRANT. 

DEEP CONVECTION REMAINS VERY ACTIVE FOR THIS TIME YEAR ALONG 
AND NEAR THE MONSOON TROUGH DIRECTLY AND INDIRECTLY ASSOCIATED
WITH THE LOW PRESSURE FEATURES MENTIONED EARLIER...INCLUDING
THE ONE UNDER SPECIAL FEATURE.

GAP WINDS...
THE COOLER AND DRIER AIRMASS THAT SETTLED IN OVER THE GULF OF
TEHUANTEPEC THE PAST FEW DAYS WITH FRESH TO STRONG NLY WINDS
HAS THIN OUT ENOUGH TO ALLOW FOR WINDS TO DIMINISH TO 20 KT
THROUGH THE CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC. 
THESE WINDS ARE FORECAST TO DIMINISH TO 10-15 KT BY WED.

$$
AGUIRRE