000
AXPZ20 KNHC 290306
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON OCT 29 2012

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 
0230 UTC.

...SPECIAL FEATURE...

A 1006 MB LOW PRES LOCATED NEAR 13N112W IS EMBEDDED WITHIN THE 
MONSOON TROUGH. EARLIER DEEP CONVECTION HAS RECENTLY WEAKENED
...HOWEVER LATEST SATELLITE IMAGERY SHOWS RATHER DISORGANIZED 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 150 NM SE
QUADRANT...AND SCATTERED MODERATE CONVECTION WITHIN 30 NM OF
13N113W. LAST FEW VISIBLE SATELLITE IMAGERY SHOWS LOW CLOUDS 
TURNING CYCLONICALLY INTO THE LOW FROM THE NE AND NW QUADRANTS. 
THE OBSERVED CONVECTION IS OVER THE SE AND S QUADRANTS. THE LOW
W REMAINS UNDER AN UPPER LEVEL ANTICYCLONE...WHICH FAVORS SOME 
SLOW DEVELOPMENT THROUGH THE NEXT 48 HRS WITH A MEDIUM CHANCE OF 
IT INTENSIFYING INTO A TROPICAL CYCLONE WITHIN THE NEXT 48 HRS.

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

MONSOON TROUGH EXTENDS FROM 07N79W NW ALONG THE PACIFIC COAST OF 
COSTA RICA AND PANAMA TO 11N91W TO LOW PRES NEAR 11N102W 1007 
MB TO LOW PRES NEAR 13N112W 1006 MB TO LOW PRES NEAR 11N122W 
1007 MB TO 07N140W. SCATTERED STRONG CONVECTION IS WITHIN 120 NM 
S OF THE TROUGH BETWEEN 116W-119W AND WITHIN 120 NM N OF TROUGH 
BETWEEN 119W-122W. SCATTERED MODERATE TO STRONG CONVECTION EXISTS
FROM 10N-15N BETWEEN 101W-107W. SCATTERED MODERATE ISOLATED 
STRONG ALONG AND WITHIN 120 NM N OF TROUGH BETWEEN 97W-101W
AND 60 NM OF TROUGH W OF 137W. SCATTERED MODERATE WITHIN 45 NM 
OF 11N93W.

...DISCUSSION...

ALOFT...AN UPPER TROUGH EXTENDS FROM FAR NW MEXICO AND NORTHERN
BAJA CALIFORNIA SW TO NEAR 26N122W. W OF IT...BROAD MID/UPPER 
LEVEL ANTICYCLONIC FLOW IS PRESENT EXCEPT W OF 138W WHERE A VERY
SHARP SHORTWAVE TROUGH IS NOTED. ELSEWHERE BROAD MID/UPPER LEVEL
CONTINUES OVER THE MAJORITY OF THE DISCUSSION AREA ASSOCIATED
WITH A MID/UPPER LEVEL ANTICYCLONE AT 11N108W. A VERY PRONOUNCED
DIFFLUENT PATTERN ALOFT TO SW OF THE ANTICYCLONE IS HELPING FIRE
UP THE CONVECTION ASSOCIATED WITH THE LOW PRES NEAR 13N111W AND 
THE 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 
VISIBLE IMAGERY REVEALS BROKEN TO OVERCAST PATCHES OF 
STRATOCUMULUS CLOUDS MOVING SSW WITH POSSIBLE ISOLATED SHOWERS 
TO THE N OF 17N AND W OF 124W.

AT THE SURFACE...A 1020 MB HIGH PRES CENTER IS ANALYZED AT 
32N133W WITH A RIDGE EXTENDING SE TO NEAR 23N121W. 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 ASCAT PASS FROM YESTERDAY AFTERNOON. 
HOWEVER...SEAS OF 8 FT IN MIXED NE AND NW SWELL STILL LINGER 
OVER THE AREA N OF 10N W OF 134W. N TO NE WINDS OF 20-25 KT N OF 
28N BETWEEN 124W-128W ARE DIMINISHING TO 15-20 KT AS THE HIGH 
CENTER OF 1022 MB SHIFTS NE. LINGERING NE AND NW SWELLS ARE 
PRODUCING SEAS OF UP TO 8 FT N OF 28N BETWEEN 124W-128W...BUT 
ARE EXPECTED TO SUBSIDE TO LESS THAN 8 FT DURING MON. NW SWELLS 
WILL MIX WITH NE SWELLS FROM 20N-26N W OF 130W AND W OF A LINE 
FROM 20N130W TO 10N140W IN 24 HRS WITH SEAS OF 8 FT. THESE 
CONDITIONS THEN SUBSIDE TO LESS THAN 8 FT IN 48 HRS AS THE 
SWELLS DIMINISH.

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...
A COLD FRONT OVER THE FAR SE PART OF THE SW GULF OF MEXICO IS 
FOLLOWED BY A COOLER AND DRIER AIRMASS. THIS DENSER AIR HAS
MIXED DOWNWARD BRINGING N-NE WINDS OF 20-30 KT THROUGH THE GULF 
OF TEHUANTEPEC WITH SEAS OF 8-11 FT. THE ASCAT PASS FROM NEAR
1630 UTC THIS AFTERNOON CONFIRMED THESE WINDS. WITH THE TIGHT
PRES GRADIENT IN PLACE OVER SE MEXICO...THESE WIND CONDITIONS 
ARE FORECAST TO GRADUALLY DIMINISH TO 20-25 KT BY TUE MORNING
...AND TO 20 KT OR LESS BY EARLY TUE EVENING WITH SEAS OF 8 FT.

$$
AGUIRRE