[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 04 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 09N13W 07N22W 08N40W 05N50W. A
SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ AND ANALYZED FROM
02N-10N ALONG 51W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS WITHIN 180 NM N OF THE ITCZ AXIS BETWEEN 39W-50W.

...DISCUSSION...

GULF OF MEXICO...
CONVERGENT FLOW ALOFT OVER THE GULF IS LEADING TO WIDESPREAD
SUBSIDENCE IN SUPPORT OF A BROAD 1022 MB HIGH CENTERED NEAR
26N88W. THIS SURFACE HIGH IS PROVIDING THE ENTIRE GULF WITH FAIR
CONDITIONS AND MOSTLY CLEAR SKIES THIS AFTERNOON.  SURFACE WINDS
ACROSS THE GULF ARE ALL BELOW 20 KT. THROUGH THE WEEKEND...AS
THE HIGH SHIFTS SOUTHWESTWARD AND WEAKENS SLIGHTLY...A COLD
FRONT CURRENTLY INLAND OVER CENTRAL TEXAS WILL BEGIN TO IMPACT
THE GULF COAST AND NORTHERN GULF WATERS SUNDAY MORNING. BY LATE
SUNDAY...N TO NE WINDS BEHIND THE FRONT WILL SPREAD SOUTHWARD AS
THE FRONT REACHES THE CENTRAL GULF OF MEXICO.

CARIBBEAN SEA...
CONVERGENT UPPER LEVEL WESTERLIES AND SOUTHWESTERLIES DOMINATE
THE WESTERN AND CENTRAL CARIBBEAN...LEADING TOWARD GENERALLY
CLEAR WEATHER WITH NO ORGANIZED DEEP CONVECTION.  FARTHER
EAST...UPPER LEVEL RIDGING EXISTS ALONG 12N AND SCATTERED
MODERATE ISOLATED DEEP CONVECTION HAS BEEN OCCURRING TODAY ALONG
THE NORTHERN COAST OF VENEZUELA AND THE ABC ISLANDS.  NO OBVIOUS
SURFACE FEATURE IS CONNECTED WITH THIS CONVECTIVE ACTIVITY.  A
WEAKENING COLD FRONT EXTENDS SOUTHWESTWARD FROM THE ATLANTIC
OCEAN INTO HISPANIOLA.  FROM THERE...A SHEAR LINE CONTINUES
SOUTHWESTWARD TO JAMAICA AND ENDS JUST EAST OF HONDURAS.  NO
DEEP CONVECTION IS OCCURRING WITH THESE BOUNDARIES...THOUGH
THERE MAY BE SOME SHALLOW CLOUD RAINFALL OCCURRING ALONG THE
BOUNDARIES...ESPECIALLY IN HISPANIOLA.  SURFACE WINDS THROUGHOUT
THE CARIBBEAN ARE GENERALLY 20 KT OR LESS OUT OF THE NORTHEAST
AS THE SURFACE PRESSURE GRADIENT IS RELAXED.  THESE WEAK TO
MODERATE WINDS SHOULD CONTINUE FOR THE NEXT DAY OR SO...WITH THE
NEXT COOL FRONT IMPACTING THE NW CARIBBEAN ON MONDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS LOCATED OVER THE W ATLC WITH AXIS
EXTENDING FROM 32N63W TO 22N70W. THIS UPPER LEVEL FEATURE
SUPPORTS A PRIMARY COLD FRONT ANALYZED FROM 32N55W SW ALONG
25N60W TO OVER HISPANIOLA. ISOLATED SHOWERS ARE OCCURRING WITHIN
90 NM EITHER SIDE OF THE FRONT. BEHIND THE FRONT...WINDS IN OUR
REGION ARE W TO NW 20 TO 25 KT.  IN THE EXTREME NORTHERN PORTION
OF OUR REGION...SW WINDS AHEAD OF A SECOND FRONTAL SYSTEM SHOULD
MAY REACH GALE FORCE W OF 68W TONIGHT AND BETWEEN 63W AND 73W
TOMORROW. EAST OF THE COLD FRONT...A WEAK 1016 MB HIGH PRESSURE
IS CENTERED NEAR 23N53W IS CONTRIBUTING TOWARD RELATIVELY WEAK
SURFACE WINDS ACROSS MOST OF THE TROPICAL AND SUBTROPICAL NORTH
ATLANTIC.  IN THE FAR EAST ATLANTIC...A COOL FRONT EXTENDS
SOUTHWESTWARD FROM 32N25W TO 22N35W AND A DISSIPATING COOL FRONT
EXTENDS SOUTHWESTWARD FROM 32N19W TO 21N28W. ISOLATED SHOWERS
ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE COOL FRONT.
AFTERNOON PASSES FROM BOTH THE ASCAT AND WINDSAT SCATTEROMETERS
INDICATED GALE FORCE SW WINDS N OF 28N BETWEEN 20W AND 30W.

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

$$
LANDSEA/HUFFMAN




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