Tropical Weather Discussion
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000
AXNT20 KNHC 180001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI OCT 17 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

THE CENTER OF HURRICANE GONZALO AT 17/2300 UTC IS NEAR 32.0N
65.0W OR ABOUT 22 NM SOUTH-SOUTHWEST OF BERMUDA. GONZALO IS
MOVING TOWARDS THE NORTH-NORTHEAST OR 25 DEGREES AT 14 KNOTS.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 951 MB. THE MAXIMUM
ESTIMATED WIND SPEED IS 100 KNOTS WITH HIGHER GUSTS. GONZALO IS
A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND
SCALE.  SLOW WEAKENING IS FORECAST...BUT GONZALO IS EXPECTED TO
BE A DANGEROUS HURRICANE WHEN IT MOVES NEAR OR OVER BERMUDA.
FASTER WEAKENING IS FORECAST TO BEGIN SATURDAY ONCE GONZALO
MOVES OVER COOL WATERS. NUMEROUS MODERATE CONVECTION IS FROM 30N-
36N BETWEEN 60W-67W. PUBLIC ADVISORIES FOR HURRICANE GONZALO ARE
ISSUED UNDER WMO HEADER WTNT33 KNHC AND UNDER AWIPS HEADER
MIATCPAT3. FORECAST/ADVISORIES FOR HURRICANE GONZALO ARE ISSUED
UNDER WMO HEADER WTNT23 KNHC AND UNDER AWIPS HEADER MIATCMAT3.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS EXTENDING
FROM 14N34W TO 3N34W...MOVING W AT 15 KT. THE SSMI TPW IMAGERY
SHOW A SLOT OF DRY AIR IN THE NORTHERN AND IMMEDIATE EASTERN
ENVIRONMENT OF THE WAVE AT THE MIDDLE TO LOWER LEVELS. THE DRY
AIR IN THE MIDDLE LEVELS IS ALSO CAPTURED BY THE GOES-R RGB
AIRMASS IMAGERY. AHEAD OF THE WAVE...A DEEP LAYER MOIST
ENVIRONMENT SUPPORT MIDDLE AND HIGH LEVEL CLOUDS AS WELL AS
SCATTERED MODERATE CONVECTION FROM 1N-10N BETWEEN 34W-43W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE EASTERN ATLC
WATERS NEAR 9N13W AND THEN CONTINUES ALONG 8N19W TO 7N24W...THE
ITCZ CONTINUES FROM THERE TO 7N31W. ISOLATED MODERATE CONVECTION
IS FROM 3N-13N BETWEEN 20W-32W.

...DISCUSSION...

...THE GULF OF MEXICO...

A BROAD MIDDLE-LEVEL ANTICYCLONE IS CENTERED ON THE GULF...THUS
SUPPORTING A SURFACE RIDGE ANCHORED BY A 1016 MB HIGH PRESSURE
CENTER NEAR 27N90W. SSMI TPW AND WATER VAPOR IMAGERY SHOW DEEP
LAYER DRY DOMINATING THE BASIN N OF 23N...WHICH IS FAVORING
CLEAR SKIES AND FAIR WEATHER. IN THE SW BASIN...SSMI TPW IMAGERY
SHOW HIGH MOISTURE BEING ADVECTED FROM THE E PAC WATERS AND
ASSOCIATED WITH THE RECENTLY FORMED TROPICAL DEPRESSION TWENTY.
THIS MOIST AIR IS ENHANCING ISOLATED SHOWERS IN THE BAY OF
CAMPECHE S OF 20N. LINGERING MOISTURE ASSOCIATED WITH A FORMER
DISSIPATING FRONTAL BOUNDARY CONTINUE TO ENHANCE SCATTERED HEAVY
SHOWERS AND TSTMS OVER THE NORTHERN AND EASTERN YUCATAN
PENINSULA. SURFACE RIDGING IS EXPECTED TO PREVAIL SATURDAY. A
COLD FRONT WILL BE MOVING ACROSS THE NORTHERN BASIN BY SUNDAY
MORNING.

...THE CARIBBEAN SEA...

LINGERING MOISTURE ASSOCIATED WITH A FORMER DISSIPATING
STATIONARY FRONT CONTINUES TO ENHANCE SCATTERED HEAVY SHOWERS
AND TSTMS OVER EASTERN CUBA AND ISOLATED SHOWERS OVER THE NW
CARIBBEAN WATERS W OF 82W. AN UPPER-LEVEL TROUGH OVER THE WESTERN
ATLC WATERS EXTENDS SOUTHWARD TO A BASE OVER THE SOUTHERN-
CENTRAL CARIBBEAN. THE PORTION OF THE TROUGH OVER THE BASIN
COINCIDES WITH A TONGUE OF MODERATE MOISTURE IN THE SSMI TPW
IMAGERY WHICH ENHANCES SCATTERED MODERATE CONVECTION AND TSTMS
ACROSS HISPANIOLA. IN THE SW BASIN...THE MONSOON TROUGH SUPPORT
SCATTERED MODERATE CONVECTION AND TSTMS S OF 13N BETWEEN 76W-
81W. STRONG DEEP LAYER ENVIRONMENTAL SHEAR SUPPORT FAIR WEATHER
ELSEWHERE. A RELAXED PRESSURE GRADIENT ACROSS THE REGION
CONTINUE TO SUPPORT WINDS IN THE RANGE OF 5-10 KT. NO
SIGNIFICANT CHANGES EXPECTED DURING THE WEEKEND.

...HISPANIOLA...

AN UPPER-LEVEL TROUGH OVER THE WESTERN ATLC WATERS EXTENDS
SOUTHWARD TO A BASE OVER THE SOUTHERN-CENTRAL CARIBBEAN. THE
PORTION OF THE TROUGH OVER THE BASIN COINCIDES WITH A TONGUE OF
MODERATE MOISTURE IN THE SSMI TPW IMAGERY WHICH ENHANCES
SCATTERED MODERATE CONVECTION AND TSTMS ACROSS HISPANIOLA.
CONVECTION IS EXPECTED TO CONTINUE OVER THE WEEKEND.

THE ATLANTIC OCEAN...

THE MAIN CONCERN OVER THE BASIN IS MAJOR HURRICANE GONZALO THAT
IS DISCUSSED IN THE SPECIAL FEATURES SECTION. MOST THE
CONVECTION ASSOCIATED WITH THE CYCLONE IS N OF THE AREA OF
DISCUSSION WITH A RAINBAND OF SCATTERED SHOWERS AND TSTMS
EXTENDING TO 24N BETWEEN 60W-66W. FARTHER EAST OVER THE CENTRAL
ATLC...A MIDDLE TO UPPER LEVEL CYCLONE SUPPORT A 1010 MB LOW
NEAR 20N47W FROM WHICH A SURFACE TROUGH EXTENDS SW TO 13N49W.
SCATTERED SHOWERS AND TSTMS ARE FROM 18N-25N BETWEEN 44W-50W.
OTHERWISE...A SURFACE TROUGH IS ANALYZED ALONG 30N15W TO 25N27W
TO 25N39W WHERE A SHEAR LINE CONTINUES TO 27N47W TO 26N54W.
SCATTERED MODERATE CONVECTION IS WITHIN 140 NM EITHER SIDE OF
THE SHEAR LINE BETWEEN 38W-43W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR


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