000
AXPZ20 KNHC 081005
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON OCT 08 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...SPECIAL FEATURE...

TROPICAL STORM OLIVIA CENTERED NEAR 16.4N 120.9W 999 MB AT 
08/0900 UTC MOVING N OR 360 DEGREES AT 06 KT. MAXIMUM SUSTAINED 
WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. OLIVIA IS MOVING N ON 
THE WESTERN PERIPHERY OF A MID TO UPPER LEVEL ANTICYCLONE 
LOCATED NEAR 15N115W. SATELLITE IMAGERY SHOWS SCATTERED MODERATE
TO STRONG CONVECTION WITHIN 90 NM OF THE CENTER IN THE NW QUADRANT
...AND ALSO WITHIN 45 NM IN THE NE QUADRANT. OLIVIA IS FORECAST
TO MAINTAIN STEADY STATE WITH ITS INTENSITY INTO THIS AFTERNOON
...THEN BEGIN TO WEAKEN TUE AS IT MOVES UNDER THE INFLUENCE OF 
INCREASING SOUTHWESTERLY SHEAR AND WHILE SEA SURFACE TEMPERATURES
BEGIN TO COOL. FOR FURTHER DETAILS SEE AWIPS/WMO HEADERS 
MIATCMEP5 AND WTPZ25 KNHC.  

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

THE MONSOON TROUGH EXTENDS W ACROSS THE SOUTHERN CARIBBEAN 
BETWEEN 11N-12N FROM EXTREME N COLOMBIA TO ACROSS CENTRAL COSTA 
RICA TO THE PACIFIC COAST AT 09N84W...THEN CONTINUES W TO 09N96W
TO 09N109W WHERE IT LOSES IDENTITY IN SOUTHERLY FLOW TO THE S OF 
TS OLIVIA. THE MONSOON TROUGH RESUMES SW OF OLIVIA AT 13N123W TO 
09N135W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ 
WHICH CONTINUES W TO BEYOND 08N140W.

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ALONG
AND WITHIN 120 NM S OF THE TROUGH BETWEEN 89W-92W...AND WITHIN
30 NM OF THE TROUGH BETWEEN 123W-135W.
 
SCATTERED MODERATE ISOLATED STRONG CONVECTION...ACCOMPANIED BY 
NUMEROUS LIGHTNING STRIKES...IS OBSERVED JUST OFFSHORE AND TO
WITHIN 60 NM OF THE PACIFIC COAST OF MUCH OF CENTRAL AMERICA.
 
...DISCUSSION...

A SHORTWAVE TROUGH HAS MOVED OVER THE NW PORTION OF THE 
DISCUSSION AREA...AND STRETCHES FROM 32N129W SW TO 26N130W WITH 
A BAND OF UPPER MOISTURE ROTATING THROUGH THE TROUGH AND STREAMING
NEWD TO OVER AND INLAND THE SOUTHERN CALIFORNIA COAST. A SECOND 
BAND OF UPPER MOISTURE IS MOVING E ACROSS THE NORTHERN BAJA 
CALIFORNIA PENINSULA CONTINUING E ACROSS THE SW U.S.

AN UPPER LEVEL ANTICYCLONE SE OF TROPICAL STORM OLIVIA AT NEAR 
15N115W EXTENDS RIDGES N BEYOND 32N115W...SE TO A CREST AT 
14.5N105W AND W TO A CREST AT 15N131W. THE DEBRIS MOISTURE FROM 
OLIVIA IS BEING ADVECTED N AND NE ACROSS THE UPPER RIDGE AT 
23N116W WHERE IT TURNS SE AND APPEARS TO REMAIN W OF THE MEXICAN 
COAST AS IT RETURNS BACK S OVER THE DEEP TROPICS.

AN UPPER SHORTWAVE TROUGH OVER THE CENTRAL CONUS EXTENDS SW 
ACROSS THE WESTERN GULF OF MEXICO AND OVER CENTRAL MEXICO TO 
BASE NEAR 14N101W. THE UPPER DIFFLUENCE E OF THE TROUGH IS 
ENHANCING CONVECTION OVER MEXICO TO THE E OF ABOUT 
98W...WITH THE DEBRIS MOISTURE ADVECTED NE ACROSS THE GULF 
OF MEXICO.

AN UPPER ANTICYCLONE OVER THE WESTERN CARIBBEAN AT 16N81W HAS 
ITS ANTICYCLONIC ENVELOPE EXTENDING S OVER THE DISCUSSION AREA 
TO THE N OF 06N AND E OF 98W. THE ASSOCIATED UPPER DIFFLUENCE IS 
SUPPORTING THE CONVECTION ALONG THE EASTERN SEGMENT OF THE 
MONSOON TROUGH AS PREVIOUSLY DESCRIBED. DENSE DEBRIS MOISTURE IS 
OBSERVED OVER THE AREA N OF 05W E OF 91W...AND FOR THE MOST PART 
IS ADVECTED N ACROSS CENTRAL AMERICA TO THE E OF 91W.

ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE IS NEAR 
29N128W WITH BROAD RIDGING COVERING THE DISCUSSION AREA N OF 22N 
W OF THE BAJA PENINSULA. MODEL GUIDANCE SUGGEST THAT THE HIGH
WILL MOVE ONLY LITTLE DURING THE NEXT 48 HRS.

GAP WINDS...THE HIGH RESOLUTION ASCAT PASS FROM JUST PAST 0400 UTC
LAST NIGHT REVEALED N WINDS OF 20-25 KT FUNNELING INTO THE GULF
OF TEHUANTEPEC. THE CURRENT SYNOPTIC PATTERN OVER SW GULF OF 
MEXICO TO OVER SE MEXICO IS FAVORABLE FOR THIS WINDS TO LAST
THROUGH TONIGHT THEN DIMINISH TUE AFTERNOON AS THE PRES GRADIENT
SLACKENS OVER SE MEXICO.

MODEL GUIDANCE IS CONSISTENT IN FORECASTING A SURFACE LOW 
DEVELOPING ALONG THE MONSOON TROUGH NEAR 10N88W LATE TUE WITH 
THE LOW MOVING W-NW THEREAFTER. THE GFS GUIDANCE CONTINUES TO
BE THE MOST AGGRESSIVE WITH WINDS TIED INTO THE LOW. WILL
BLEND THE LESS AGGRESSIVE ECMWF WITH THE GFS IN THE LONG TERM
PORTION OF THE GRIDS TO SHOW A WEAKER LOW FOR NOW. WILL AWAIT 
FUTURE GFS GUIDANCE TO SEE IF COMES MORE IN LINE WITH THE 
OTHER GLOBAL MODELS.
 
$$
AGUIRRE