[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED NOV 18 2015

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.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 14N54W TO 07N54W...MOVING W AT ABOUT 15 TO 20 KT
WITHIN THE LAST 24 HOURS. SSMI TPW IMAGERY DEPICTS MODERATE TO
HIGH MOISTURE IN THE ENVIRONMENT OF THE WAVE MAINLY S OF 11N.
ISOLATED MODERATE CONVECTION IS OBSERVED ALONG THE WAVE
AXIS...WITH A HIGHER CONCENTRATION AT ABOUT 180 NM E FROM THE
AXIS.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 18N69W TO 12N69W...MOVING W AT 15 TO 20 KT WITHIN
THE LAST 24 HOURS. THE WAVE IS EMBEDDED IN A MODERATE MOIST
ENVIRONMENT. A SHORTWAVE TROUGH IS CURRENTLY TO THE W OF THE
WAVE ENHANCING CONVECTION NOT ONLY IN THE WAVE ENVIRONMENT BUT
ACROSS THE CENTRAL CARIBBEAN FROM 65W-75W. THE WAVE IS FORECAST
TO WEAKEN INTO A SURFACE TROUGH AND DISSIPATE WITHIN THE NEXT
24 HOURS.

...ITCZ/MONSOON TROUGH...

THE ITCZ EXTENDS FROM 09N13W AND CONTINUES TO 04N31W TO 06N57W.
ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE AXIS
BETWEEN 25W AND 30W.

...DISCUSSION...

...THE GULF OF MEXICO...

A MID TO UPPER-LEVEL TROUGH OVER THE CENTRAL UNITED STATES
EXTENDS INTO THE WESTERN GULF OF MEXICO SUPPORTING A FRONTAL
SYSTEM ANALYZED AS A COLD FRONT FROM SW ALABAMA NEAR 30N87W TO
26N91W TO A 1009 MB LOW OVER THE BAY OF CAMPECHE NEAR 20N96W.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE ALONG
THIS FRONT AFFECTING THE GULF WATERS N OF 26N. THIS CONVECTION IS
ALSO SUPPORTED BY A DIFFLUENT FLOW ALOFT GENERATED BY THE
INTERACTION OF THE UPPER-LEVEL TROUGH PREVIOUSLY MENTIONED AND
AN UPPER-LEVEL ANTICYCLONE ANCHORED OVER THE GULF OF TEHUANTEPEC
THAT EXTENDS NE ACROSS THE BASIN. SCATTEROMETER DATA DEPICTS
MODERATE NORTHERLY FLOW ACROSS THE NORTHERN GULF N OF THE FRONT
WHILE MODERATE TO FRESH SOUTHERLY FLOW PREVAILS S OF THE FRONT.
EXPECT FOR THE FRONT TO CONTINUE MOVING SE ACROSS THE BASIN WITH
CONVECTION. WINDS ARE EXPECTED TO INCREASE BEHIND THE FRONT TO
NEAR GALE FORCE WITHIN THE NEXT 48 HOURS.

...CARIBBEAN SEA...

A TROPICAL WAVE IS IN THE EASTERN CARIBBEAN WITH AXIS ALONG 69W.
PLEASE REFER TO THE SECTION ABOVE FOR DETAILS. THE UPPER-LEVEL
ANTICYCLONE CENTERED OVER THE GULF OF TEHUANTEPEC ALSO EXTENDS
ACROSS THE W CARIBBEAN MAINLY W OF 80W. A SHORTWAVE TROUGH
EXTENDS FROM THE ATLANTIC ACROSS THE CENTRAL CARIBBEAN BETWEEN
73W-80W. AT THE SURFACE...A LOW IS CENTERED NEAR 11N82W. ALL
THESE FEATURES COMBINE TO SUPPORT SCATTERED MODERATE CONVECTION
ACROSS THE CENTRAL CARIBBEAN BETWEEN 66W-81W. SCATTEROMETER DATA
DEPICTS MODERATE TO FRESH TRADES ACROSS THE BASIN. THE LOW IS
FORECAST TO STAY NEARLY STATIONARY DURING THE NEXT 24
HOURS...ASSOCIATED CONVECTION WILL PERSIST THROUGH THIS PERIOD.
A STRONG PRESSURE GRADIENT BETWEEN A RIDGE OVER THE W ATLANTIC
EXTENDING ACROSS THE NORTHERN CARIBBEAN AND THE LOW IN THE SW
BASIN WILL SUPPORT FRESH TO STRONG WINDS FROM 13N TO 16N BETWEEN
72W AND 77W WITH SEAS UP TO 9 FT. WINDS AND SEAS ARE FORECAST TO
DIMINISH BY EARLY FRIDAY.

...HISPANIOLA...

SCATTERED MODERATE CONVECTION ARE OVER THE CENTRAL CARIBBEAN
INCLUDING HISPANIOLA SUPPORTED BY AN UPPER-LEVEL TROUGH
EXTENDING FROM THE ATLANTIC TO A BASE NE OF COSTA RICA. THIS
ACTIVITY IS EXPECTED TO DIMINISH WITHIN THE NEXT 24 HOURS AS THE
TROUGH ALOFT MOVES E.

...ATLANTIC OCEAN...

A WARM FRONT EXTENDS ACROSS THE W ATLANTIC FROM 31N80W TO
26N74W. TO THE E...AN UPPER-LEVEL TROUGH EXTENDS ACROSS THE
CENTRAL ATLANTIC SUPPORTING A FRONTAL SYSTEM ANALYZED AS A COLD
FRONT FROM 30N71W TO 31N46W. S OF THIS FRONT...A WEAKENING COLD
FRONT IS FROM 24N70W TO 31N46W. SCATTERED MODERATE CONVECTION IS
ALONG BOTH BOUNDARIES BETWEEN 41N70W. SCATTEROMETER DATA
DEPICTS FRESH TO STRONG NORTHERLY WINDS N OF THE FRONTAL
BOUNDARIES WHILE GENTLE TO MODERATE WINDS PREVAIL ELSEWHERE. A
TROPICAL WAVE IS MOVING ACROSS THE CENTRAL TROPICAL ATLANTIC.
PLEASE REFER TO THE SECTION ABOVE FOR DETAILS. OVER THE NEXT 24
HOURS...THE WARM FRONT WILL CONTINUE MOVING N AWAY OF OUR AREA.
THE COLD FRONTS OVER THE CENTRAL ATLANTIC WILL MERGE. CONVECTION
IS EXPECTED ACROSS THE AREA.

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

$$

ERA
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