[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU DEC 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE WEST
AFRICAN COAST AT 07N12W TO 06N34W TO ALONG 04N13W TO 04N24W TO
06N34W TO THE EQUATOR NEAR 49W. WHILE NO SIGNIFICANT CONVECTION
IS NOTED ALONG THE ITCZ AXIS...A SURFACE THE EQUATOR AT 49W AT
THE COAST OF BRAZIL.  NO SIGNIFICANT DEEP CONVECTION IS
ASSOCIATED WITH THE ITCZ AT THIS TIME.  IN THE SOUTHWESTERN
CARIBBEAN...THE MONSOON TROUGH EXTENDS ACROSS PANAMA TO 09N76W
AT THE COAST OF COLOMBIA.  NO SIGNIFICANT DEEP CONVECTION IS
ASSOCIATED WITH THE MONSOON TROUGH AT THIS TIME.

...DISCUSSION...

GULF OF MEXICO...
1027 MB SURFACE HIGH IS CENTERED NORTHEAST OF THE GULF NEAR
33N82W ALONG THE BORDER OF GEORGIA AND SOUTH CAROLINA.  SURFACE
WINDS ARE GENERALLY SOUTHEASTERLY TO SOUTHERLY OVER THE GULF AT
15 TO 20 KT. NO DEEP CONVECTION IS OCCURRING OVER THE GULF OF
MEXICO AT THIS TIME AND ONLY WIDELY SCATTERED SHOWERS ARE
APPARENT ON RADAR ALONG THE UPPER TEXAS COAST.  IN THE UPPER-
LEVELS...A WEAK TROUGH IN THE WESTERLIES IS SEEN ALONG THE EAST
MEXICAN COAST...THOUGH IT IS NOT ASSOCIATED WITH ANY COHERENT
SURFACE FEATURE.  ALSO A WEAK FAST-MOVING TROUGH IN THE UPPER
LEVELS IS MOVING ALONG THE FLORIDA PANHANDLE.  THIS SYSTEM MAY
BE ENHANCING SOME UPPER-LEVEL CLOUDINESS...BUT NOT CONTRIBUTING
TOWARD ANY SHOWER ACTIVITY AT THIS TIME.  DURING THE NEXT
DAY...THE SURFACE CIRCULATION SHOULD REMAIN ABOUT THE SAME...BUT
THERE WILL BE ADDITIONAL MOISTURE ADVECTION IN THE
SOUTHEASTERLIES IN THE WESTERN HALF OF THE GULF.  THIS ENHANCE
THE CHANCE FOR SOME SHOWER ACTIVITY ON FRIDAY IN THE REGION.

CARIBBEAN SEA...
A MODERATE PRESSURE GRADIENT EXISTS OVER THE CARIBBEAN SEA
BETWEEN THE SEMI-PERMANENT LOW OVER SOUTH AMERICA AND A 1027 MB
BERMUDA HIGH. THIS IS PRODUCING EAST TO NORTHEASTERLY TRADEWINDS
OF GENERALLY 15 TO 25 KT WITH THE TYPICAL ENHANCEMENT OF THE
WINDS ALONG THE COAST OF COLOMBIA TO 30 KT.  TOTAL PRECIPITABLE
WATER IMAGERY INDICATES THREE LOCAL MAXIMA OF MOIST CONDITIONS
IN THE LOW-LEVELS...85W...75W...AND 65W.  DESPITE THESE MOISTURE
MAXIMA...NO SIGNIFICANT DEEP CONVECTION IS OCCURRING OVER THE
CARIBBEAN TODAY INCLUDING THE GREATER ANTILLES AND CENTRAL
AMERICA.  IN THE UPPER LEVELS...A SUBSIDENT HIGH IS CENTERED
OVER COLOMBIA AND ANTICYCLONICALLY TURNING FLOW DOMINATES OVER
THE CARIBBEAN.  SOME UPPER-LEVEL MOISTURE AND CLOUDINESS IS
BEING ADVECTED NORTHEASTWARD OVER THE WESTERN CARIBBEAN FROM
SOME EARLIER DEEP CONVECTION OVER CENTRAL AMERICA AND THE
NORTHEAST PACIFIC.  DURING THE NEXT DAY...NO SIGNIFICANT CHANGE
IN THE SURFACE WINDS IS ANTICIPATED THOUGH THE MOISTURE MAXIMA
OVER 75W MAY ENHANCE CHANCES FOR SHOWERS OVER CENTRAL AMERICA.

...HISPANIOLA...
AS WITH THE REST OF THE CARIBBEAN...NO SIGNIFICANT DEEP
CONVECTION HAS BEEN OCCURRING OVER HISPANIOLA TODAY.  EASTERLY
TRADEWINDS MAY PRODUCE SOME SCATTERED SHOWERS IN THE DOMINICAN
REPUBLIC AND ALONG THE SOUTHERN COAST OF HAITI ON FRIDAY DUE TO
THE COMBINATION OF UPSLOPE FLOW AND AFTERNOON HEATING.
HOWEVER...NO LARGE AMOUNTS OF PRECIPITATION ARE EXPECTED.

ATLANTIC OCEAN...
A COLD FRONT EXTENDS FROM 32N54W WEST-SOUTHWESTWARD TO 27N73W.
NO SHOWER ACTIVITY IS ASSOCIATED WITH THE FRONT AT THIS TIME.
AHEAD OF THE FRONT IS A TROUGH...AN EX-FRONTAL BOUNDARY...
EXTENDING FROM 30N56W WEST-SOUTHWESTWARD TO 24N76W IN THE
CENTRAL BAHAMAS.  SCATTERED SHOWERS EXIST WITHIN 60 NM OF THE
TROUGH AXIS.  NEITHER THE FRONT NOR THE TROUGH ARE ASSOCIATED
WITH MORE THAN 20 KT OF WIND.   THE ASSOCIATED SHORT-WAVE TROUGH
IN THE UPPER LEVELS HAS ALREADY MOVED TO 60W AT 30N...SO LITTLE
DYNAMICAL SUPPORT FOR THE FRONT OR SURFACE TROUGH IS EXPECTED.
THE TROUGH AND FRONT WILL LIKELY MERGE WITHIN THE NEXT DAY...BUT
ONLY SCATTERED SHOWERS SHOULD PERSIST IN ASSOCIATION WITH THESE
FEATURES.  WELL TO THE EAST...ANOTHER TROUGH AXIS EXISTS FROM
06N35W TO 15N33W WITH NE WINDS 20 TO 30 KT EAST OF THE TROUGH
AXIS.  THE SURFACE TROUGH IS ASSOCIATED WITH A VIGOROUS UPPER-
LEVEL LOW CENTERED NEAR 21N34W...WHICH IS RETROGRADING WESTWARD.
 LITTLE DEEP CONVECTION IS ASSOCIATED WITH THE SURFACE
TROUGH/UPPER LOW...BUT WIDESPREAD SHOWERS AND MID-TO UPPER-LEVEL
CLOUDINESS EXTENDS FROM 10N TO 25N AND 20W TO 33W.  THIS TROUGH
IS LIKELY TO WEAKEN SOME...BUT THE SHOWERS WILL PERSIST FOR THE
NEXT DAY OR SO.

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

$$
LANDSEA

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