000 AXNT20 KNHC 042347 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU DEC 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 7N12W TO 5N17W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 5N30W TO 5N46W. MODERATE MOISTURE IN THE MIDDLE- TO LOWER- LEVELS ALONG WITH DIFFLUENT FLOW ALOFT SUPPORT AN AREA OF SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 5N-16N BETWEEN 20W-40W. ...DISCUSSION... GULF OF MEXICO... A BROAD RIDGE OVER THE EASTERN CONUS ANCHORED BY A 1033 MB HIGH NE OF LAKE ONTARIO EXTENDS SW INTO THE GULF. A WEAKNESS IN THE RIDGE IS ANALYZED AS A SURFACE TROUGH IN THE BAY OF CAMPECHE ALONG 26N95W TO 18N94W WITH NO CONVECTION ASSOCIATED WITH IT. SSMI TPW IMAGERY SHOW MODERATE MOISTURE ADVECTION FROM THE CARIBBEAN TO THE NW GULF WHICH IS SUPPORTING BROKEN TO OVERCAST SKIES AND FOG N OF 27N W OF 91W. NE-E WINDS IN THE RANGE OF 5-15 KT COVER THE GULF E OF 92W. NE TO SE WIND FLOW OF THE SAME MAGNITUDE IS OVER THE REMAINDER WESTERN GULF. SURFACE RIDGING WILL CONTINUE TO DOMINATE THE BASIN THROUGH SAT...THEN A STATIONARY FRONT EXTENDS ALONG THE NORTHERN BASIN SUN. CARIBBEAN SEA... EXCEPT FOR THE FAR NW AND SE CARIBBEAN...ABUNDANT MOISTURE IN THE MIDDLE- TO LOWER-LEVELS DOMINATES ACROSS THE WATERS. A MAXIMUM IN MOISTURE IS OBSERVED OVER THE SW BASIN COINCIDING WITH DIFFLUENT FLOW ALOFT AND THE BASE OF A MIDDLE-LEVEL TROUGH. THE MIDDLE-LEVEL TROUGH SUPPORTS A SURFACE TROUGH FROM 16N78W TO 10N79W WHICH IS ENHANCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION AND TSTMS S OF 16N W OF 73W. A SURFACE TROUGH OVER THE ATLC EXTENDS SW TO THE NE CARIBBEAN...THUS SUPPORTING SCATTERED SHOWERS OVER THE LEEWARD ISLANDS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALSO NOTED ACROSS PUERTO RICO...HISPANIOLA AND ADJACENT WATERS. SHOWERS IN THE SW AND NE CARIBBEAN WILL PERSIST THROUGH SATURDAY NIGHT. HISPANIOLA... LOW- TO MIDDLE-LEVEL MOISTURE CONTINUES TO MOVE ACROSS THE NORTHERN AND AND CENTRAL CARIBBEAN. THIS MOIST AIRMASS ALONG WITH A MIDDLE-LEVEL TROUGH SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE HISPANIOLA AND ADJACENT WATERS. SHOWERS OVER THE ISLAND ARE EXPECTED THROUGH FRI MORNING AND WILL REMAIN ACROSS SE ADJACENT WATERS THROUGH LATE FRI NIGHT. ATLANTIC OCEAN... A MIDDLE-LEVEL CYCLONE CENTERED NEAR 26N63W SUPPORT A SURFACE TROUGH ALONG 25N60W TO THE NE CARIBBEAN NEAR 16N63W. DIFFLUENT FLOW ALOFT COINCIDING WITH THE NORTHERN TROUGH AREA SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS FROM 23N-30N BETWEEN 50W- 64W. SCATTEROMETER DATA SHOW A SHEAR LINE EXTENDING FROM 30N42W TO 29N50W TO 29N60W. SURFACE RIDGING DOMINATES ELSEWHERE. A LOW PRESSURE CENTER IS EXPECTED TO FORM ALONG THE SURFACE TROUGH FRI MORNING DRIFTING NE AND N OF THE AREA OF DISCUSSION BY SUN MORNING. SURFACE RIDGING WILL PREVAIL E OF THE TROUGH WHILE A NEW COLD FRONT ENTERS THE SW N ATLC SUN MORNING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR