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000
AXNT20 KNHC 041745
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 04 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
07N11W TO 07N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N19W TO 06N24W TO 08N36W TO 03N48W. SCATTERED
MODERATE CONVECTION IS FROM 01N-08N BETWEEN 08W-17W. ISOLATED
MODERATE CONVECTION IS FROM 03N-09N BETWEEN 27W-38W...AND FROM
04N-08N BETWEEN 48W-53W.

...DISCUSSION...

GULF OF MEXICO...
WESTERLY TO NORTHWESTERLY UPPER LEVEL FLOW IS NOTED ON WATER
VAPOR IMAGERY OVER THE GULF THIS AFTERNOON ON THE NORTHERN
PERIPHERY OF A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER SOUTHERN MEXICO NEAR 19N92W. MOSTLY DRY AIR AND
UPPER LEVEL STABILITY IS SUPPORTING SURFACE CONDITIONS THAT
REMAIN FAIRLY STABLE AS WELL UNDER SOUTHERLY RETURN FLOW IN THE
RANGE OF 10 TO 15 KT. ONLY A FEW AREAS OF ISOLATED SHOWERS ARE
OCCURRING ACROSS THE GULF GENERALLY N OF 25N AT THIS TIME.
LOOKING AHEAD...AN AREA OF LOW PRESSURE CONTINUES TO DEVELOP
ACROSS THE INTERMOUNTAIN WEST THIS AFTERNOON. THE ASSOCIATED
COLD FRONTAL BOUNDARY CURRENTLY ANALYZED OVER OKLAHOMA AND NW
TEXAS IS FORECAST TO MOVE SOUTHEASTWARD THROUGH LATE THURSDAY
AND EMERGE OFF THE TEXAS AND LOUISIANA COASTS BY EARLY TO MID-
DAY FRIDAY INTO SATURDAY.

CARIBBEAN SEA...
NORTHWESTERLY DRY AND STABLE UPPER LEVEL FLOW IS NOTED ON WATER
VAPOR NW OF A BROAD UPPER LEVEL TROUGH AXIS EXTENDING FROM
19N70W TO 13N83W. THE STABLE CONDITIONS ALOFT ARE RESULTING IN
CLEAR SKIES AND FAIR CONDITIONS AT THE SURFACE WITH ONLY A FEW
ISOLATED SHOWERS OCCURRING IN THE ADJACENT COASTAL WATERS OF
WESTERN CUBA FROM 20N-22N BETWEEN 80W-83W. EAST OF THE UPPER
LEVEL TROUGH AXIS...WESTERLY UPPER LEVEL FLOW DOMINATES WITH AN
AREA OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE NOTED N OF 15N
E OF 70W. WITH AMPLE DYNAMICS ALOFT...A SURFACE TROUGH IS
ANALYZED FROM 15N74W NE TO WESTERN PUERTO RICO AND INTO THE SW
NORTH ATLC NEAR 23N62W. WIDELY SCATTERED SHOWERS AND ISOLATED
TSTMS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE SURFACE
TROUGH AXIS. OTHERWISE...TRADE WIND FLOW REMAINS GENERALLY
WITHIN THE 10 TO 20 KT RANGE. AS AN AREA OF HIGH PRESSURE MOVES
OFF THE MID-ATLC AND SE U.S. COAST...THE PRESSURE GRADIENT
ACROSS THE CARIBBEAN WILL STRENGTHEN WITH TRADES FORECAST TO
GRADUALLY INCREASE BETWEEN 70W-82W LATER THIS EVENING THROUGH
THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND.

...HISPANIOLA...
CURRENTLY A SURFACE TROUGH AXIS EXTENDS SOUTH AND EAST OF THE
ISLAND ANALYZED FROM 15N73W TO 23N62W. WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF
THE SURFACE TROUGH AXIS AND THIS INCLUDES THE MONA PASSAGE AND
THE EXTREME EASTERN PORTIONS OF HISPANIOLA E OF 71W. THE
BOUNDARY IS FORECAST TO REMAIN RELATIVELY STATIONARY OVER THE
NEXT 24 TO 36 HOURS AND GRADUALLY DISSIPATE...HOWEVER LOW-LEVEL
MOISTURE AND THE POSSIBILITY OF ISOLATED SHOWERS AND TSTMS WILL
PERSIST ACROSS EASTERN PORTIONS OF THE ISLAND.

ATLANTIC OCEAN...
A BROAD MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE SW NORTH ATLC WITH AXIS EXTENDING ALONG 69W TO
A BASE IN THE VICINITY OF THE MONA PASSAGE NEAR 19N69W. THE
TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION
AREA NEAR 32N54W EXTENDING SW TO 24N64W. BROADER-SCALE SURFACE
TROUGHING EXTENDS FROM THE TAIL END OF THE COLD FRONT NEAR
23N62W SW TO ACROSS PUERTO RICO AND INTO THE NORTH-CENTRAL
CARIBBEAN SEA. SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF
25N WITHIN 330 NM EAST OF THE COLD FRONT AND ISOLATED SHOWERS
AND TSTMS ARE OCCURRING FROM 18N-25N BETWEEN 58W-68W IN
ASSOCIATION WITH THE SURFACE TROUGH. OTHERWISE...THE REMAINDER
OF THE SW NORTH ATLC WEST OF THE COLD FRONT IS UNDER THE
INFLUENCE OF RELATIVELY DRY AND STABLE NORTHWESTERLY FLOW ALOFT
AND A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED OFF THE
COAST OF THE CAROLINAS NEAR 34N73W. FINALLY...A DEEP LAYERED LOW
IS CENTERED OVER THE EASTERN ATLC NEAR 32N29W WITH THE SURFACE
LOW ANALYZED AS AT 995 MB. THE OCCLUDED LOW HAS A TRIPLE POINT
IN THE VICINITY OF THE MADEIRA ISLANDS NEAR 33N18W WITH A WARM
FRONT STRETCHING SE TO THE WEST AFRICAN COAST NEAR 28N13W AND A
COLD FRONT EXTENDING SW FROM THE TRIPLE POINT TO 22N28W.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING MAINLY NEAR THE LOW
CENTER WITHIN 240 NM OF THE LOW CENTER.

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

$$
HUFFMAN