[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111719
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 11 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 MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 07N12W TO 07N16W WHERE THE ITCZ BEGINS AND CONTINUES
ALONG 02N51W. SCATTERED MODERATE CONVECTION 02N-06N E OF 30W.
...DISCUSSION...

GULF OF MEXICO...

A 1027 MB HIGH CENTERED OVER ARKANSAS-MISSISSIPPI ALONG WITH A
MODERATE N-S PRESSURE GRADIENT IS ALLOWING CONTINUED COLD AIR
ADVECTION WITH WINDS OF 5 TO 15 KT ACROSS THE EASTERN TWO-THIRDS
OF THE GULF OF MEXICO.  WEAK SE RETURN FLOW HAS COMMENCED IN THE
EXTREME NORTHWESTERN 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 WESTERLIES AS PART OF THE
SUBTROPICAL JET STREAM ARE OBSERVED OVER THE GULF...ADVECTING
MOISTURE AND HIGH CLOUDS BUT NO SIGNIFICANT PRECIPITATION.

CARIBBEAN SEA...

A STATIONARY FRONTAL BOUNDARY IS LOCATED FROM HAITI
SOUTHWESTWARD TO JUST OFFSHORE OF NICARAGUA.  THE COMBINATION OF
HIGH PRESSURE NORTHWEST OF THE FRONT ALONG WITH LOW PRESSURE
OVER PANAMA AND COLOMBIA ARE CONTRIBUTING TOWARD 20-25 KT NE
WINDS OVER THE SOUTHWESTERN CARIBBEAN...AS SEEN BY THE 1524Z
ASCAT SCATTEROMETER PASS.  ELSEWHERE...THE TRADEWINDS ARE
GENERALLY 10-20 KT ACROSS THE CARIBBEAN. ADDITIONALLY...
SCATTERED MODERATE CONVECTION IS OBSERVED FROM 10-12N BETWEEN 75-
80W AS A RESULT OF THE FRONTAL BOUNDARY INTERACTING WITH THE
EASTERN END OF THE PACIFIC ITCZ.  ELSEWHERE...NO SIGNIFICANT
DEEP CONVECTION IS OCCURRING OVER THE CARIBBEAN UNDER TYPICALLY
SUBSIDENT AND DRY MID TO UPPER LEVEL WESTERLY TO SOUTHWESTERLY
FLOW. WHILE THE FRONTAL BOUNDARY SHOULD DISSIPATE WITHIN A DAY
OR SO...CONTINUED COOL AIR ADVECTION SHOULD OCCUR ACROSS THE NW
CARIBBEAN DURING THE NEXT TWO DAYS.

HISPANIOLA...

A STATIONARY FRONTAL BOUNDARY IS LOCATED OVER HAITI THIS
MORNING.  NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH
IT...THOUGH ISOLATED LOW-TOPPED SHOWERS ARE POSSIBLE DURING THE
NEXT TWO DAYS.  WINDS ARE NE 10-15 KT NEAR HAITI AND THE
SOUTHERN COAST OF DOMINICAN REPUBLIC WITH WEAKER WINDS ALONG THE
NORTHERN COAST OF DOMINICAN REPUBLIC.  OVER THE NEXT TWO
DAYS...ISOLATED SHOWERS ARE POSSIBLE BUT THESE SHOULD NOT
WIDESPREAD NOR DEEP CONVECTION.  THE COASTAL WINDS SHOULD
DIMINISH SOME DURING THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...

A COLD FRONT EXTENDS FROM 32N59W SOUTHWESTWARD TO HISPANIOLA.
MODERATE CONVECTION EXISTS WITHIN 60 NM OF THE FRONT NORTH OF
29N.  THE FRONT SHOULD DISSIPATE WITHIN THE NEXT DAY OR SO.  A
NEW COLD FRONTAL BOUNDARY SHOULD REACH OUR NORTHEASTERN BOUNDARY
BY FRIDAY MORNING A QUICKLY PROGRESS SOUTHEASTWARD.  A 1014 MB
SURFACE LOW IS LOCATED NEAR 26N40W WITH A TROUGH EXTENDING
SOUTHEASTWARD A FEW HUNDRED NM.  NO SIGNIFICANT DEEP CONVECTION
IS ASSOCIATED WITH THIS LOW...THOUGH EASTERLY WINDS OF 20 KT ARE
PRESENT WITHIN THE NORTHERN SEMICIRCLE.  AN UPPER-LEVEL LOW IS
HELPING TO PRODUCT MODERATE CONVECTION FROM 25-30N BETWEEN 27-
30W.  IT IS ANTICIPATED THAT THE LOW AND UPPER-LEVEL WILL
DISSIPATE IN ABOUT A DAY.

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

$$
LANDSEA

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