Tropical Weather Discussion
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000
AXNT20 KNHC 201117
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURE...

A 1011 MB SURFACE LOW CENTERED NEAR 28N45W IS GENERATING GALE
FORCE WINDS ACROSS THE CENTRAL ATLANTIC PARTICULARLY WITHIN 180
NM E SEMICIRCLE OF THE LOW CENTER. THIS SYSTEM IS GENERATING
SEAS UP TO 15 FT IN THE AREA OF STRONGEST WINDS. THE LOW IS
FORECAST TO MOVE JUST N OF THE AREA WITHIN THE NEXT 12 HOURS. AS
A RESULT...A GALE WARNING IS IN EFFECT THROUGH EARLY THIS
AFTERNOON.

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

THE MONSOON TROUGH CROSSES THE COAST OF AFRICA NEAR 07N12W TO
06N16W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 05N33W TO
02N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
03N-08N E OF 34W.

...DISCUSSION...

GULF OF MEXICO...

UPPER-LEVEL SW TO W FLOW CONTINUES ACROSS THE BASIN ADVECTING
MOISTURE FROM THE ITCZ IN THE EPAC TO THE GULF WATERS. A 1014 MB
SURFACE LOW IS OVER THE NW PORTION OF THE BASIN NEAR 28N93W FROM
WHICH A COLD FRONT EXTENDS SW TO NE MEXICO. A STATIONARY FRONT
EXTENDS EASTWARD FROM THE SAME LOW ALONG 29N88W TO 29N84W.
ISOLATED CONVECTION IS OBSERVED BEHIND THE FRONTS AFFECTING THE
NORTHERN GULF WATERS WITH A N MODERATE BREEZE. FAIR WEATHER AND
A SLIGHT BREEZE PREVAILS OVER THE REMAINDER OF THE BASIN AS A
BROAD SURFACE RIDGE COVERING THE EASTERN U.S. EXTENDS S TO THE
GULF. A SURFACE TROUGH OVER THE W CARIBBEAN IS ENHANCING
CONVECTION AFFECTING THE YUCATAN CHANNEL. OVER THE NEXT 24 HOURS
EXPECT FOR THE LOW TO MOVE E-NE ALONG THE NORTHERN GULF WHILE
WEAKENING...AND ITS ASSOCIATED COLD FRONT WILL EXTEND SW TO
EASTERN-CENTRAL MEXICO COASTAL WATERS.

CARIBBEAN SEA...

A SURFACE TROUGH IS OVER THE YUCATAN PENINSULA EXTENDING FROM
23N87W TO 18N88W. DEEP LAYER MOISTURE IN THE FAR WESTERN BASIN
MAINLY W OF 82W IS ENHANCING SCATTERED MODERATE CONVECTION N OF
20N W OF 83W. AN UPPER-LEVEL TROUGH EXTENDS ACROSS THE SE
CARIBBEAN SUPPORTING ISOLATED CONVECTION AFFECTING THE ADJACENT
WATERS OF THE LESSER ANTILLES AND PUERTO RICO. FAIR WEATHER
PREVAILS ELSEWHERE ACROSS THE BASIN SUPPORTED BY DRY AIR
SUBSIDENCE FROM ALOFT. A SLIGHT TO GENTLE BREEZE PREVAILS ACROSS
THE BASIN. OVER THE NEXT 24 HOURS EXPECT LINGERING MOISTURE
ASSOCIATED WITH THE SURFACE TROUGH TO CONTINUE ENHANCING
CONVECTION OVER THE NW BASIN THROUGH THE WEEKEND.

HISPANIOLA...

FAIR WEATHER IS PREVAILING ACROSS THE ISLAND AS AN UPPER-LEVEL
HIGH CONTINUES SUPPORTING SUBSIDENCE. SIMILAR CONDITIONS ARE
EXPECTED OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

A BROAD MID-LEVEL TROUGH OVER THE W ATLANTIC CONTINUES TO
SUPPORT A SURFACE PRE-FRONTAL TROUGH THAT EXTENDS FROM 31N58W TO
28N63W. TO THE E...A 1011 MB SURFACE LOW IS CENTERED NEAR
28N45W. ITS COLD FRONT EXTENDS FROM THE LOW TO 22N40W. A WARM
FRONT EXTENDS N FROM THE LOW TO THE N ATLANTIC. SCATTERED
MODERATE CONVECTION PREVAILS N OF 22N BETWEEN 37W-47W. GALE
FORCE WINDS ARE OBSERVED E OF THIS LOW CENTER. FOR MORE
INFORMATION...PLEASE REFER TO THE SPECIAL FEATURE SECTION ABOVE.
SURFACE RIDGING PREVAILS ACROSS THE EASTERN PORTION OF THE BASIN
SUPPORTING FAIR WEATHER. OVER THE NEXT 24 HOURS...EXPECT FOR THE
LOW OVER THE CENTRAL ATLANTIC TO MOVE NW N OF THE AREA OF
DISCUSSION. CONVECTION WILL CONTINUE IN THE VICINITY OF THE LOW.

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

$$
ERA



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