000
AXPZ20 KNHC 192142
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI OCT 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

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

THE MONSOON TROUGH IS ALONG 14N90W TO 10N104W TO 12N115W TO 
11N130W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 
11N130W TO 10N140W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 09N TO 14N BETWEEN 89W AND 93W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE MONSOON 
TROUGH BETWEEN 103W AND 106W...FROM 10N TO 12N BETWEEN 130W AND 
132W...AND ALSO WITHIN 60 NM EITHER SIDE OF A LINE FROM 10N135W 
TO 07N138W.

...DISCUSSION...

THE REMNANTS OF PAUL...NOW IN THE FORM OF A TROUGH...REACHES 
FROM 31N125W TO 14N126W. THIS SURFACE FEATURE IS IN ASSOCIATION 
WITH A NEARLY STATIONARY UPPER LEVEL LOW NEAR 29N123W. NEARBY 
SCATTEROMETER PASSES INDICATED PRIMARILY LIGHT TO MODERATE 
WINDS N OF 20N E OF 130W INCLUDING IN THE VICINITY OF THE 
TROUGH. SCATTERED SHOWERS ARE STILL POSSIBLE N OF 20N BETWEEN 
118W AND 130W IN ASSOCIATION WITH THE TROUGH. THIS TROUGH IS 
FORECAST TO DISSIPATE THIS WEEKEND WHILE REMAINING NEARLY 
STATIONARY.

1025 MB SURFACE HIGH PRES 34N147W EXTENDS A RIDGE TO THE SE TO 
NEAR 24N132W. MODERATE TO LOCALLY FRESH WINDS ARE UNDER THIS 
RIDGE N OF THE ITCZ W OF 130W. WHILE WINDS ARE 20 KT OR LESS...A 
LINGERING AREA OF NW 8 TO 9 FT SWELL IS PRESENT N OF 25N W OF 
130W. MODEL GUIDANCE CONTINUES TO INDICATE A BRIEF EPISODE OF 
FRESH TO STRONG NE WINDS IN THE FAR NW CORNER OF THE DISCUSSION 
AREA COMMENCING LATER THIS EVENING THROUGH EARLY SAT AS THE PRES 
GRADIENT TIGHTENS JUST ENOUGH TO ALLOW FOR SUCH CONDITIONS. 
THESE WINDS WILL HELP TO REINFORCE THE AREA OF LINGERING SWELL 
WITH NE WIND WAVES CONTRIBUTING...ALTHOUGH THIS WILL BE SHORT 
LIVED WITH SEAS SUBSIDING TO LESS THAN 8 FT BY SAT NIGHT.

A REGION OF DEEP CONVECTION NEAR THE MONSOON TROUGH BETWEEN 89W 
AND 93W HAS A LOW-LEVEL VORTICITY MAXIMUM ASSOCIATED WITH IT. AS 
THIS AREA PROGRESSES WESTWARD...THIS SHOULD INDUCE A WEAK 
TEHUANTEPEC GAP WIND EVENT COMMENCING EARLY SAT. THE GFS IS THE 
MOST AGGRESSIVE MODEL WITH A WEAK LOW DEVELOPING SOUTH OF THE 
MEXICO-GUATEMALA BORDER BY SAT MORNING AND INDUCING N TO NE 
WINDS UP TO 25 KT. THIS IS MAINTAINED WITHIN THE HIGH SEAS 
THOUGH IF THE OTHER MODELS ARE CORRECT IN LESS DEVELOPMENT...THE 
WINDS MAY END UP BELOW OUR 25 KT CRITERION. BECAUSE OF CONTINUED 
MODERATE HIGH PRES IN THE GULF OF MEXICO AND LOW PRES IN THE 
NORTHEAST PACIFIC MONSOON TROUGH...THIS WEAK TEHUANTEPEC EVENT 
MAY CONTINUE FOR ABOUT A WEEK. IN GENERAL...THE GAP WINDS WILL 
BE MOST PROMINENT IN LATE NIGHT-EARLY MORNING AND WEAKEST DURING 
THE AFTERNOON-EARLY EVENING MINIMUM.

THE AFOREMENTIONED DISTURBANCE IS ROBUSTLY SPUN UP INTO A 
TROPICAL CYCLONE BY MON WITHIN THE 12Z GFS S OF SOUTHERN MEXICO 
BUT REMAINS SUBSTANTIALLY WEAKER WITHIN THE GFS ENSEMBLE MEAN. 
THE REMAINING GLOBAL MODEL GUIDANCE ONLY SHOWS AN E TO W 
EXTENDED MONSOON TROUGH THROUGH EARLY NEXT WEEK. THE GRIDDED 
FORECAST WILL FAVOR THE MODEL CONSENSUS OF NO DEVELOPMENT AND 
DOWNPLAY...AT THIS TIME...ANY TROPICAL DEVELOPMENT. EVEN SO...IT 
IS QUITE SHOCKING TO SEE THE GFS DEPICTING A HURRICANE BY WED 
AND THE OTHER MODELS SHOWING ALMOST NOTHING.

$$
LEWITSKY