000
AXPZ20 KNHC 111005
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU OCT 11 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...

A LOW 1009 MB LOW IS EMBEDDED ALONG THE MONSOON TROUGH AT 12N91W.
THIS LOW IS PART OF AN ELONGATED TROUGH OF LOW PRES THAT 
STRETCHES FROM OFFSHORE OF THE COAST OF CENTRAL AMERICA AND 
SOUTHERN MEXICO FOR SEVERAL HUNDRED MILES. ATMOSPHERIC CONDITIONS
ARE CONDUCIVE FOR SOME GRADUAL DEVELOPMENT OF THIS LOW PRES AREA
OVER THE NEXT 48 HRS AS IT MOVES WESTWARD WITH A MEDIUM CHANCE 
OF INTENSIFYING INTO A TROPICAL STORM.

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

THE MONSOON TROUGH EXTENDS W FROM ACROSS SOUTHERN COSTA RICA TO 
THE PACIFIC COAST AT 09N85W AND CONTINUES NW TO 1009 MB LOW PRES 
AT 12N91W TO 1010 MB LOW PRES AT 11N103W TO 10N114W TO 1010 MB 
LOW PRES AT 10N126W TO 10N135W WHERE IT TRANSITIONS TO THE ITCZ 
AXIS TO BEYOND 08N140W. SCATTERED STRONG CONVECTION IS WITHIN 60 
NM OF THE MONSOON TROUGH BETWEEN 132W-137W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS WITHIN 120 NM S OF THE OF THE MONSOON TROUGH
BETWEEN 104W-110W...AND ALSO WITHIN 60 NM S OF THE MONSOON 
TROUGH BETWEEN 122W-130W.

...DISCUSSION...

A LARGE UPPER LEVEL LOW N OF THE DISCUSSION AREA IS NEAR 34N122W
...AND MOVING ESE TOWARDS THE SRN CALIFORNIA COAST WITH AN 
ASSOCIATED UPPER TROUGH EXTENDING SW FROM IT THROUGH 32N122W AND 
S TO 22N122W THEN SE TO NEAR 19N128W. THE ASSOCIATED SURFACE LOW
IS JUST W OF THE CALIFORNIA COAST 25N121.5W WITH A TROUGH SE TO
32N119W AND SW TO 27N125W. ISOLATED SHOWERS ARE POSSIBLE ALONG
THE TROUGH. THE UPPER LEVEL LOW IS FORECAST TO MOVE INLAND THE 
SRN CALIFORNIA COAST THIS AFTERNOON WITH THE SURFACE LOW AND 
TROUGH DISSIPATING AS A HIGHLY AMPLIFIED RIDGE OVER THE NW PORTION
OF THE AREA QUICKLY SLIDES EASTWARD WHILE DAMPENING OUT AND AS
NRN STREAM ENERGY BEHIND IT SPLITS INTO TWO BRANCHES. THE SRN BRANCH
WILL DRIVE AN UPPER LEVEL LOW SE ACROSS THE FAR NRN PORTION LATE FRI
NIGHT INTO SAT. THIS WILL PUSH A SURFACE COLD FRONT ACROSS THE 
NRN WATERS...BUT WILL BE RATHER WEAK AS THE UPPER LEVEL LOW WEAKENS
AS IT IS NUDGED BACK TO THE W BY UPPER LEVEL RIDGING TO
ITS N.

AN UPPER LEVEL ANTICYCLONE IS OVER CENTRAL MEXICO AT 19N100W 
WITH AN UPPER RIDGE EXTENDING WSW TO A CREST AT 14N122W. THE 
FLOW AROUND THE ANTICYCLONE IS ADVECTING UPPER DEBRIS MOSITURE 
FROM THE MONSOON TROUGH NWD ON THE WRN PERIPHERY OF THE 
ANTICYCLONE. BROAD SW UPPER LEVEL FLOW EXISTS BETWEEN THE RIDGE
AND THE UPPER TROUGH TO ITS N DESCRIBED ABOVE. CLOUD MOTION 
VECTORS AND UPPER LEVEL MODEL GUIDANCE INDICATE SW WINDS OF 
50-70 KT ASSOCIATED WITH A JET STREAM BRANCH THAT ROUNDS THE 
SE PERIPHERY OF THE UPPER LEVEL LOW N OF THE AREA.

AN UPPER ANTICYCLONE E OF THE PACIFIC BASIN OVER THE GULF OF 
HONDURAS HAS ITS ANTICYCLONIC ENVELOPE EXTENDING S OVER THE 
DISCUSSION AREA TO THE N OF ABOUT 10N AND E OF 102W. THE 
ASSOCIATED UPPER DIFFLUENCE IS SUPPORTING THE CONVECTION ALONG 
THE EASTERN SEGMENT OF THE MONSOON TROUGH AS PREVIOUSLY 
DESCRIBED AS WELL CONVECTION OF GUATEMALA...AND IN THE VICINITY 
GULF OF TEHUANTEPEC. DENSE DEBRIS MOISTURE FROM THIS CONVECTION
IS SPREADING WWD AROUND THE SRN PERIMETER OF THE ANTICYCLONE
AT 19N100W AND COMBINING WITH THE UPPER DEBRIS MOISTURE FOUND
ON ITS THE SW PERIPHERY. 

ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE OF 1022 MB
IS ANALYZED NEAR 28N132W WITH BROAD RIDGING COVERING THE AREA
N OF 18N AND W OF 117W. THE REMNANT LOW OF FORMER TROPICAL STORM 
OLIVIA IS ANALYZED TO BE NEAR 12N129W AND RAPIDLY WEAKENING. THE 
ASCAT PASS FROM 0630 UTC THIS MORNING AGAIN SHOWED A SWATH OF NE 
20-25 KT WINDS WITHIN 210 NM OF THE LOW IN THE NW QUADRANT. 
THESE WINDS WILL CONTINUE THROUGH TODAY...THEN DIMINISH TO 20 KT 
W OF A LINE FROM 10N123W TO 10N131W TONIGHT.

GAP WINDS...N-NE WINDS WILL PULSE AT 20-25 KT THROUGH AND 
DOWNSTREAM THE GULF OF TEHUANTEPEC REACHING NEAR 15N96W THROUGH
TODAY AS HIGHLIGHT IN THE LATEST ASCAT/OSCAT SCATTEROMETER PASSES
AS WELL AS IN PREVIOUS ONES. MODEL WIND AND STABILITY GUIDANCE 
INDICATES THAT THESE WINDS WILL PULSE THROUGH THE GULF DURING THE
NEXT 48 HRS.

THE 1009 MB LOW ALONG THE MONSOON TROUGH AS MENTIONED ABOVE 
UNDER SPECIAL FEATURE WILL BE FURTHER AIDED IN ITS POTENTIAL 
TO DEVELOP INTO A TROPICAL SYSTEM AS IT DRAWS IN VORTICITY
DOWNSTREAM SPARKED BY THE GULF OF TEHUANTEPEC GAP WINDS. ANOTHER
LOW TO ITS W AT 10N126W 1010 MB WILL ALSO MOVE WNW DURING THE NEXT
48 HRS AS DEPICTED BY THE GLOBAL MODELS.

ACCORDING TO WAVEWATCH MODEL GUIDANCES NW SWELLS WILL CONTINUE 
TO MOVE INTO THE WRN PORITON OF THE AREA FROM 10N TO 20N W OF 
127W THROUGH TGHE NEXT 24 HRS PRODUCING SEAS OF 8-11 FT WITH 
THE HIGHEST IN THE NW PART. THE NW SWELL WILL COMBINE WITH 
NE SWELLS THROUGH EALRY TONIGHT BEFORE BEING TAKING OVER BY 
THE MORE PREDOMINATE NW SWELL TRAIN. BY FRI NIGT...THE 8-10 FT
SEAS WILL BE W OF LINE FRM 20N120W TO 14N126W TO 11N140W.
 
$$
AGUIRRE