Tropical Weather Discussion
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000
AXPZ20 KNHC 311524
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1500 UTC.

...SPECIAL FEATURES...
TROPICAL STORM VANCE IS THE 20TH NAMED STORM OF THE EASTERN
NORTH PACIFIC HURRICANE SEASON. VANCE IS CENTERED NEAR 10.1N
100.8W OR ABOUT 475 NM S OF ACAPULCO MEXICO AT 31/1500 UTC
MOVING TOWARD THE SOUTH-SOUTHWEST OR 195 DEGREES AT 3 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED
WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. NUMEROUS MODERATE TO
STRONG FROM 09N TO 13N BETWEEN 97W AND 102W. 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.

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.

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

MONSOON TROUGH FROM 9N83W TO 10N94W...THEN RESUMES FROM 9N108W
TO 12N125W TO 12N131W. ITCZ FROM 12N131W TO 10N140W. SCATTERED
MODERATE TO STRONG CONVECTION N OF 3N BETWEEN 78-82W AND WITHIN
60 NM S OF AXIS FROM 121W-123W.

...DISCUSSION...
A COLD FRONT IS OVER THE NW CORNER OF THE AREA AND EXTENDS FROM
30N128W TO 25N140W. NW SWELL 8 TO 11 FT NW OF 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.

$$
DGS



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