[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU DEC 10 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
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM 03N AND THE PRIME MERIDIAN
TO 04N09W...WHERE THE INTERTROPICAL CONVERGENCE ZONE AXIS BEGINS
AND EXTENDS TO 05N20W TO 06N30W TO 06N44W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 05N E OF 05W.
SCATTERED MODERATE CONVECTION IS FROM 02N TO 08N BETWEEN 20W AND
44W.

...DISCUSSION...

GULF OF MEXICO...

A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE FL PANHANDLE AND
SOUTHWESTWARD ACROSS THE GULF OF MEXICO TO NEAR 22N94W. THIS
TROUGH CONTINUES TO SLIDE EASTWARD...PROPAGATING WITH IT ASCENT
ON THE EASTERN SIDE OF THE TROUGH. A SURFACE TROUGH IS EVIDENT
UNDER THIS REGION OF ASCENT FROM NEAR 27N83W TO 22N83W.
SCATTERED SHOWERS AND THUNDERSTORMS ARE MAINLY SE OF A LINE FROM
25N81W TO 21N88W. ELSEWHERE...A 1019 MB HIGH CENTERED NEAR
27N87W SUPPORTS MAINLY MODERATE ANTICYCLONIC WINDS AND GENERALLY
FAIR WEATHER OVER THE GULF BASIN THIS EVENING...WITH LIGHT WINDS
WITHIN 100 NM OF THE HIGH CENTER. OVER THE NEXT 24 HOURS THE MID
TO UPPER LEVEL TROUGH WILL MOVE E OVER THE SW N ATLC. MID LEVEL
RIDGING WILL DEVELOP ACROSS THE GULF IN THE WAKE OF THE
TROUGH...WHILE THE SURFACE HIGH MOVES NE OVER THE ATLC WITH AN
AXIS CONTINUING OVER THE NE GULF. THIS PATTERN WILL BRING DRIER
CONDITIONS TO THE SE GULF BY LATE FRI MORNING...WITH ONGOING
FAIR CONDITIONS OVER THE REST OF THE GULF BASIN THROUGH FRI
NIGHT. ON SATURDAY THE PRESSURE GRADIENT WILL INCREASE OVER THE
WESTERN GULF BETWEEN THE HIGH OVER THE ATLC AND LOW PRESSURE
DEVELOPING INLAND OVER THE CENTRAL US. THE RESULT COULD BE FRESH
TO STRONG SOUTHERLY WINDS OVER THE NW GULF BY SAT AFTERNOON.

CARIBBEAN SEA...

THE MID TO UPPER LEVEL TROUGH OVER THE GULF OF MEXICO SUPPORTS A
SURFACE TROUGH FROM NEAR 27N83W TO THE NW CARIBBEAN NEAR 22N83W.
THE COMBINATION OF ASCENT FROM THESE FEATURES AND ABUNDANT LOW
LEVEL MOISTURE SUPPORTS SCATTERED MODERATE CONVECTION WITHIN 100
NM OF A LINE FROM 18N82W TO 22N75W. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE ELSEWHERE OVER THE NW CARIBBEAN N OF
20N. GENERALLY FAIR WEATHER IS OCCURRING ACROSS THE REMAINDER OF
THE CARIBBEAN BASIN THIS EVENING WITH A BROAD REGION OF DRY AIR
AND SUBSIDENCE INDICATED IN WATER VAPOR IMAGERY S OF 18N.
MODERATE TO FRESH EASTERLY TRADE WINDS COVER THE CENTRAL AND
EASTERN CARIBBEAN. LIGHT TO MODERATE NE WINDS DOMINATE THE NW
CARIBBEAN...WHILE FRESH TO MODERATE NE WINDS COVER THE SW
CARIBBEAN. THE MID TO UPPER TROUGH WILL MOVE E OVER THE NEXT 24
HOURS...SHIFTING THE FOCUS FOR CONVECTION TO THE SE OVER THE
WESTERN CARIBBEAN THROUGH FRIDAY.

...HISPANIOLA...

A WEAK UPPER LEVEL DISTURBANCE COMBINED WITH MODERATE MOISTURE
AND DAYTIME HEATING HAS SUPPORTED ISOLATED THUNDERSTORMS OVER
THE CENTRAL PORTION OF HISPANIOLA. THIS ACTIVITY SHOULD DIMINISH
LATE THIS EVENING. CONVECTION A COUPLE HUNDRED NM TO THE W OF
HISPANIOLA IS ASSOCIATED WITH FORCING DUE TO A MID TO UPPER
TROUGH OVER THE EASTERN GULF. THIS TROUGH WILL MOVE OVER THE SW
N ATLC ON FRIDAY. THE FORCING THAT SUPPORTS THE CURRENT
CONVECTION TO THE W WILL ALSO MOVE EAST IN TANDEM WITH THE
TROUGH...POSSIBLY AFFECTING HAITI WITH INCREASING CHANCES FOR
THUNDERSTORMS BY FRI EVENING.

ATLANTIC OCEAN...

A MID TO UPPER LEVEL TROUGH TO THE E OF THE US E COAST SUPPORTS
A STATIONARY FRONT THAT EXTENDS OFFSHORE THE EASTERN US TO
31N77W TO 29N80W. THIS SAME TROUGH ALSO SUPPORTS A 1010 MB
SURFACE LOW NEAR 29N66W. A COLD FRONT EXTENDS FROM THE LOW TO
28N65W TO 25N71W TO 22N80W. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE W OF 72W N OF THE COLD FRONT...INCLUDING THE
BAHAMAS AND OFFSHORE WATERS E OF THE FL PENINSULA. SCATTERED
MODERATE CONVECTION IS FROM 20N TO 23N BETWEEN 74W AND 77W...AND
WITHIN 120 NM OF A LINE FROM 24N69W TO 31N61W. A STATIONARY
FRONT EXTENDS TO THE NE OF THE LOW TO 32N60W THEN SE TO
30N54W...WHERE A COLD FRONT THEN EXTENDS NE TO A STORM SYSTEM
OVER THE N CENTRAL ATLC. NO DEEP CONVECTION IS NOTED WITH THE
COLD FRONT. FARTHER EAST...A PRE-FRONTAL TROUGH EXTENDS FROM
31N35W TO 26N42W. THIS TROUGH BISECTS A SURFACE RIDGE ANCHORED
BY A 1022 MB HIGH CENTERED NEAR 26N49W...AND A 1021 MB HIGH NEAR
27N32W. A SURFACE TROUGH IS OVER THE TROPICAL CENTRAL ATLC WITH
AN AXIS EXTENDING FROM 09N44W TO 02N47W. ISOLATED MODERATE
CONVECTION IS FROM 01N TO 04N BETWEEN 43W AND 47W. ANOTHER
SURFACE TROUGH IS JUST W OF THE N AFRICA COAST EXTENDING FROM
30N17W TO 18N17W. NO DEEP CONVECTION IS NOTED WITH THIS TROUGH.
OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE S AND E OF THE
LOW CENTERED NEAR 29N66W...AS THE LOW MOVES TO THE NE.
CONVECTION WILL ALSO CONTINUE OR INCREASE OVER THE SE BAHAMAS AS
THE REMNANTS OF THE COLD FRONT INTERACT WITH AN UPPER LEVEL
TROUGH.

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

$$
LATTO
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