000
AXPZ20 KNHC 310913
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC FRI OCT 31 2014

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 
0730 UTC.                       

...SPECIAL FEATURES...                                    
TROPICAL STORM VANCE IS THE 20TH NAMED STORM OF THE EASTERN 
NORTH PACIFIC HURRICANE SEASON. VANCE IS CENTERED NEAR 10.5N 
101.0W OR ABOUT 390 NM...725 KM S OF ACAPULCO MEXICO AT 31/0900 
UTC MOVING TOWARD THE WEST-SOUTHWEST OR 245 DEGREES AT 3 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED 
WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. NUMEROUS MODERATE TO 
STRONG CONVECTION WAS WITHIN 240 NM NE SEMICIRCLE AND ELSEWHERE 
WITHIN 90 NM NW QUADRANT OF CENTER. GRADUAL STRENGTHENING IS 
FORECAST OVER THE NEXT TWO DAYS AS VANCE MOVES TO THE W. SEE THE 
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

SCATTEROMETER DATA FROM AROUND 1600 UTC THU SHOWED 20-30 KT NLY 
WINDS ACROSS THE TEHUANTEPEC REGION. THE PRESSURE GRADIENT 
BETWEEN HIGH PRES BUILDING BEHIND A COLD FRONT IN THE GULF OF 
MEXICO AND TROPICAL STORM VANCE TO THE S IS FUNNELING NORTHERLY 
WINDS THROUGH CHIVELA PASS. THESE WINDS ARE FORECAST TO INCREASE 
TO GALE FORCE LATER THIS MORNING AS DRAINAGE FLOW REACHES A 
MAXIMUM. STRONG VERTICAL MIXING OF THE WINDS ALOFT IS EXPECTED 
AS THE COLD...DRY AIR BEHIND THE FRONT MOVES OVER THE WARM WATER 
IN PLACE IN THE GULF OF TEHUANTEPEC. WINDS WILL INCREASE TO 40 
KT AS THE COLD FRONT PASSES THROUGH SOUTHERN MEXICO THIS 
EVENING. THIS GALE FORCE WIND EVENT IS FORECAST TO PERSIST AT 
LEAST THROUGH THE END OF THE FORECAST PERIOD EARLY SUN MORNING 
AND WILL LIKELY BE THE SECOND GALE FORCE EVENT OF THE COLD 
SEASON 2014-2015. 
                    
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO 10N86W TO 09N92W 
TO 10N96W...THEN RESUMES FROM 10N105W TO 12N122W TO 08N140W. 
SCATTERED MODERATE TO STRONG CONVECTION WAS OVER WATERS WITHIN 
120 NM N AND 240 NM S OF THE AXIS E OF 89W AND FROM 12N TO 14N 
BETWEEN 88W AND 93W. 
 
...DISCUSSION...                                                
A COLD FRONT IS OVER THE NW CORNER OF THE AREA AND EXTENDS FROM 
30N131W TO 25N140W. WINDS AT OR ABOVE A STRONG BREEZE NEAR THE 
FRONT HAVE DIMINISHED THIS EVENING. NW SWELL TO 9 FT CAN BE 
FOUND OVER THE FAR NW WATERS BEHIND THE FRONT. THIS SWELL IS 
FORECAST TO CONTINUE SE ACROSS THE FORECAST AREA...WITH SEAS 
EXPECTED TO BUILD AS HIGH AS 12 FT. AS THE COLD FRONT BEGINS TO 
DISSIPATE EARLY SAT...HIGH PRES IS EXPECTED TO BUILD OVER N 
WATERS. THIS WILL INCREASE THE PRES GRADIENT BETWEEN THE 
SUBTROPICAL HIGH AND THE MONSOON TROUGH...WITH TRADEWINDS 
INCREASING TO A FRESH TO STRONG BREEZE OVER WATERS N OF THE 
MONSOON TROUGH/ITCZ TO 21N AND W OF 130W. 

NE WINDS IN THE GULF OF PAPAGAYO ARE EXPECTED TO INCREASE TO A 
FRESH TO STRONG BREEZE EARLY SUN AS THE COLD FRONT CURRENTLY IN 
THE GULF OF MEXICO MOVES ACROSS THE WESTERN CARIBBEAN SEA. 

$$ 
SCHAUER