[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 07N12W TO 05N20W WHERE THE ITCZ BEGINS AND CONTINUES
ALONG 04N34W TO 01N50W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 04N-08N E OF 18W. SCATTERED MODERATE
CONVECTION IS WITHIN 160 NM EITHER SIDE OF THE ITCZ BETWEEN 20W-
35W.

...DISCUSSION...

GULF OF MEXICO...

A 1027 MB HIGH CENTERED OVER SE MISSOURI ALONG WITH A MODERATE N-
S PRESSURE GRADIENT CONTINUE TO ALLOW COLD AIR ADVECTION WITH N-
NE WINDS OF 5 TO 15 KT ACROSS THE BASIN EXCEPT FOR THE NW GULF
WHERE SE RETURN FLOW OF SIMILAR MAGNITUDE PREVAILS. NO
SIGNIFICANT DEEP CONVECTION IS OCCURRING UNDER GENERALLY DRY AND
SUBSIDENT FLOW AT THE MIDDLE TO LOWER LEVELS. 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...THE SUBTROPICAL JET STREAM CONTINUES TO
SUPPORT STRONG WESTERLIES OVER THE GULF...WHICH ADVECT MOISTURE
AND HIGH CLOUDS FROM THE EPAC WATERS...HOWEVER WITH NO
SIGNIFICANT PRECIPITATION.

CARIBBEAN SEA...

MODERATE MOISTURE IS BEING ADVECTED FROM THE SW-CENTRAL ATLC
INTO THE EASTERN AND NORTHERN-CENTRAL CARIBBEAN...THUS ENHANCING
ISOLATED SHOWERS ACROSS THE LESSER ANTILLES AND HISPANIOLA
COASTAL WATERS. ABUNDANT MOISTURE CONTINUES OVER THE SW
CARIBBEAN BASIN COINCIDING WITH A ZONE OF UPPER-LEVEL DIVERGENCE
THAT ENHANCES SCATTERED MODERATE CONVECTION S OF 13N BETWEEN 73W-
83W. COMBINATION OF HIGH PRESSURE OVER THE NW CARIBBEAN ALONG
WITH LOW PRESSURE OVER COSTA RICA...PANAMA AND COLOMBIA
CONTRIBUTE TOWARD 20-25 KT NE WINDS OVER THE SOUTHWESTERN
CARIBBEAN. ELSEWHERE...THE TRADEWINDS ARE GENERALLY 10-20 KT AND
NO DEEP CONVECTION IS OCCURRING SUPPORTED BY SUBSIDENT AND DRY
MID- TO UPPER-LEVEL WESTERLY TO SOUTHWESTERLY FLOW. COOL AIR
ADVECTION IS FORECAST TO CONTINUE ACROSS THE NW CARIBBEAN DURING
THE NEXT TWO DAYS.

HISPANIOLA...

SHALLOW MOISTURE ASSOCIATED WITH A SURFACE TROUGH N OF THE
ISLAND AND BEING ADVECTED FROM THE E CARIBBEAN CONTINUE TO
ENHANCE ISOLATED SHOWERS ON THE ISLAND COASTAL WATERS. THESE
ISOLATED SHOWERS MAY CONTINUE THROUGH SATURDAY MORNING.
HOWEVER...MODEL GUIDANCE INDICATES HIGH MOISTURE FROM THE SW
CARIBBEAN WILL MOVE ACROSS THE ISLAND SAT NIGHT THROUGH TUESDAY
MORNING...THUS RESUMING THE SHOWER ACTIVITY. NO DEEP CONVECTION
IS ANTICIPATED.

ATLANTIC OCEAN...

THE TAIL OF A DISSIPATING STATIONARY FRONT IS ANALYZED FROM
30N57W TO 26N60W WITH ISOLATED SHOWERS WITHIN 20 NM EITHER SIDE
OF THE BOUNDARY. A 1015 MB SURFACE LOW IS LOCATED NEAR 25N41W
WITH A TROUGH EXTENDING FROM 29N43W SE TO 23N40W LACKING DEEP
CONVECTION. ON THE EASTERN ATLC...A SURFACE TROUGH IS FROM
29N18W TO 25N21W ENHANCING SHOWERS ACROSS THE CANARY ISLANDS.
SURFACE RIDGING DOMINATES ELSEWHERE. IT IS ANTICIPATED THAT THE
LOW WILL DISSIPATE IN ABOUT A DAY.

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

$$
NR


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