[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121725
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

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

THE ITCZ BEGINS AT THE COAST OF WEST AFRICA NEAR 05N09W AND
CONTINUES WESTWARD TO 04N52W. SCATTERED MODERATE CONVECTION
EXISTS EAST OF 30W WITHIN 60 NM OF THE ITCZ AXIS.

...DISCUSSION...

GULF OF MEXICO...

A 1030 MB HIGH CENTERED OVER TENNESSEE-KENTUCKY ALONG WITH A
MODERATE N-S PRESSURE GRADIENT IS ALLOWING CONTINUED COLD AIR
ADVECTION WITH WINDS OF 5 TO 15 KT ACROSS THE EASTERN HALF OF
THE GULF OF MEXICO.  WEAK SE RETURN FLOW CONTINUES IN THE
WESTERN GULF.  NO SIGNIFICANT DEEP CONVECTION IS OCCURRING UNDER
GENERALLY DRY AND SUBSIDENT FLOW.  LITTLE CHANGE IS EXPECTED AT
THE SURFACE FOR THE NEXT COUPLE OF DAYS AS THE HIGH REMAINS
RATHER LOCKED IN PLACE OVER THE SOUTHEAST UNITED STATES.  IN THE
UPPER-LEVELS...STRONG WEST-SOUTHWESTERLIES AS PART OF THE
SUBTROPICAL JET STREAM ARE OBSERVED OVER THE GULF...ADVECTING
MOISTURE AND HIGH CLOUDS BUT NO SIGNIFICANT PRECIPITATION.

CARIBBEAN SEA...

THE COLD AIR ADVECTION OVER THE GULF CONTINUES SOUTHWARD...
COVERING THE WESTERN CARIBBEAN...THOUGH THE ORIGINATING FRONTAL
BOUNDARY HAS DISSIPATED. WINDS ARE PEAKING AT 25-30 KT IN THE
SOUTHWESTERN CARIBBEAN...AS SEEN BY THE 1504Z ASCAT
SCATTEROMETER...WITH A CONTRIBUTION FROM GRADIENT INDUCED BY THE
SEMI-PERMANENT LOW OVER PANAMA-COLOMBIA. ELSEWHERE...THE
TRADEWINDS ARE GENERALLY 10-20 KT ACROSS THE CARIBBEAN.
ADDITIONALLY...SCATTERED MODERATE CONVECTION IS OBSERVED FROM 10-
14N BETWEEN 80-84W ALONG THE EASTERN END OF THE NORTHEAST
PACIFIC MONSOON TROUGH.  ELSEWHERE...NO SIGNIFICANT DEEP
CONVECTION IS OCCURRING OVER THE CARIBBEAN UNDER TYPICALLY
SUBSIDENT AND DRY MID TO UPPER LEVEL WESTERLY FLOW. CONTINUED
COOL AIR ADVECTION SHOULD OCCUR ACROSS THE NW CARIBBEAN DURING
THE NEXT TWO DAYS...THOUGH THE PRESSURE GRADIENT WILL RELAX
SOME...ALLOWING THE WINDS IN THE SW CARIBBEAN TO DIMINISH.

HISPANIOLA...

A STATIONARY TROUGH...THE REMNANTS OF A COLD FRONT...IS LOCATED
JUST NORTH OF HISPANIOLA TODAY.  NO SIGNIFICANT DEEP CONVECTION
IS ASSOCIATED WITH IT...THOUGH ISOLATED LOW-TOPPED SHOWERS ARE
POSSIBLE DURING THE NEXT TWO DAYS.  WINDS ARE E 10-15 KT ALONG
THE SOUTHERN COAST OF HISPANIOLA WITH WEAKER WINDS ALONG THE
NORTHERN COAST.  OVER THE NEXT TWO DAYS...ISOLATED SHOWERS ARE
POSSIBLE BUT THESE SHOULD NOT BE WIDESPREAD NOR BECOME DEEP
CONVECTION. THE COASTAL WINDS SHOULD REMAIN WEAK DURING THE NEXT
COUPLE OF DAYS.

ATLANTIC OCEAN...

A DISSIPATING STATIONARY FRONT EXTENDS FROM 32N57W SOUTHWESTWARD
TO 26N63W AND BECOMES A TROUGH THAT EXTENDS TO EASTERN CUBA. NO
SIGNIFICANT DEEP CONVECTION EXISTS ALONG THE FRONT/TROUGH...
THOUGH ISOLATED SHOWERS MAY BE OCCURRING WITHIN 60 NM OF THE
FRONT/TROUGH.  THE FRONT/TROUGH SHOULD DISSIPATE WITHIN THE NEXT
DAY.  A NEW COLD FRONTAL BOUNDARY HAS REACHED OUR NORTHEASTERN
BOUNDARY EXTENDING FROM 32N70W TO 30N76W.  THIS SHOULD QUICKLY
PROGRESS SOUTHEASTWARD...BUT WITHOUT PRODUCING ANY SIGNIFICANT
WINDS IN OUR AREA. A 1015 MB SURFACE LOW IS LOCATED NEAR 23N44W.
NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THIS
LOW...THOUGH NORTHEASTERLY WINDS OF 20 KT ARE PRESENT WITHIN THE
NORTHERN SEMICIRCLE.  THIS LOW SHOULD DISSIPATE BY SATURDAY.  A
BUILDING AND SOUTHWARD MOVING AZORES HIGH SHOULD HELP INDUCE A
LARGE AREA OF 20-30 KT WINDS IN THE EASTERN ATLANTIC BY SUNDAY.

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

$$
LANDSEA

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