000 AXNT20 KNHC 041745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST WED DEC 04 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 07N11W TO 07N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N19W TO 06N24W TO 08N36W TO 03N48W. SCATTERED MODERATE CONVECTION IS FROM 01N-08N BETWEEN 08W-17W. ISOLATED MODERATE CONVECTION IS FROM 03N-09N BETWEEN 27W-38W...AND FROM 04N-08N BETWEEN 48W-53W. ...DISCUSSION... GULF OF MEXICO... WESTERLY TO NORTHWESTERLY UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY OVER THE GULF THIS AFTERNOON ON THE NORTHERN PERIPHERY OF A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER SOUTHERN MEXICO NEAR 19N92W. MOSTLY DRY AIR AND UPPER LEVEL STABILITY IS SUPPORTING SURFACE CONDITIONS THAT REMAIN FAIRLY STABLE AS WELL UNDER SOUTHERLY RETURN FLOW IN THE RANGE OF 10 TO 15 KT. ONLY A FEW AREAS OF ISOLATED SHOWERS ARE OCCURRING ACROSS THE GULF GENERALLY N OF 25N AT THIS TIME. LOOKING AHEAD...AN AREA OF LOW PRESSURE CONTINUES TO DEVELOP ACROSS THE INTERMOUNTAIN WEST THIS AFTERNOON. THE ASSOCIATED COLD FRONTAL BOUNDARY CURRENTLY ANALYZED OVER OKLAHOMA AND NW TEXAS IS FORECAST TO MOVE SOUTHEASTWARD THROUGH LATE THURSDAY AND EMERGE OFF THE TEXAS AND LOUISIANA COASTS BY EARLY TO MID- DAY FRIDAY INTO SATURDAY. CARIBBEAN SEA... NORTHWESTERLY DRY AND STABLE UPPER LEVEL FLOW IS NOTED ON WATER VAPOR NW OF A BROAD UPPER LEVEL TROUGH AXIS EXTENDING FROM 19N70W TO 13N83W. THE STABLE CONDITIONS ALOFT ARE RESULTING IN CLEAR SKIES AND FAIR CONDITIONS AT THE SURFACE WITH ONLY A FEW ISOLATED SHOWERS OCCURRING IN THE ADJACENT COASTAL WATERS OF WESTERN CUBA FROM 20N-22N BETWEEN 80W-83W. EAST OF THE UPPER LEVEL TROUGH AXIS...WESTERLY UPPER LEVEL FLOW DOMINATES WITH AN AREA OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE NOTED N OF 15N E OF 70W. WITH AMPLE DYNAMICS ALOFT...A SURFACE TROUGH IS ANALYZED FROM 15N74W NE TO WESTERN PUERTO RICO AND INTO THE SW NORTH ATLC NEAR 23N62W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. OTHERWISE...TRADE WIND FLOW REMAINS GENERALLY WITHIN THE 10 TO 20 KT RANGE. AS AN AREA OF HIGH PRESSURE MOVES OFF THE MID-ATLC AND SE U.S. COAST...THE PRESSURE GRADIENT ACROSS THE CARIBBEAN WILL STRENGTHEN WITH TRADES FORECAST TO GRADUALLY INCREASE BETWEEN 70W-82W LATER THIS EVENING THROUGH THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND. ...HISPANIOLA... CURRENTLY A SURFACE TROUGH AXIS EXTENDS SOUTH AND EAST OF THE ISLAND ANALYZED FROM 15N73W TO 23N62W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE SURFACE TROUGH AXIS AND THIS INCLUDES THE MONA PASSAGE AND THE EXTREME EASTERN PORTIONS OF HISPANIOLA E OF 71W. THE BOUNDARY IS FORECAST TO REMAIN RELATIVELY STATIONARY OVER THE NEXT 24 TO 36 HOURS AND GRADUALLY DISSIPATE...HOWEVER LOW-LEVEL MOISTURE AND THE POSSIBILITY OF ISOLATED SHOWERS AND TSTMS WILL PERSIST ACROSS EASTERN PORTIONS OF THE ISLAND. ATLANTIC OCEAN... A BROAD MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC WITH AXIS EXTENDING ALONG 69W TO A BASE IN THE VICINITY OF THE MONA PASSAGE NEAR 19N69W. THE TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N54W EXTENDING SW TO 24N64W. BROADER-SCALE SURFACE TROUGHING EXTENDS FROM THE TAIL END OF THE COLD FRONT NEAR 23N62W SW TO ACROSS PUERTO RICO AND INTO THE NORTH-CENTRAL CARIBBEAN SEA. SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 25N WITHIN 330 NM EAST OF THE COLD FRONT AND ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 18N-25N BETWEEN 58W-68W IN ASSOCIATION WITH THE SURFACE TROUGH. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC WEST OF THE COLD FRONT IS UNDER THE INFLUENCE OF RELATIVELY DRY AND STABLE NORTHWESTERLY FLOW ALOFT AND A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED OFF THE COAST OF THE CAROLINAS NEAR 34N73W. FINALLY...A DEEP LAYERED LOW IS CENTERED OVER THE EASTERN ATLC NEAR 32N29W WITH THE SURFACE LOW ANALYZED AS AT 995 MB. THE OCCLUDED LOW HAS A TRIPLE POINT IN THE VICINITY OF THE MADEIRA ISLANDS NEAR 33N18W WITH A WARM FRONT STRETCHING SE TO THE WEST AFRICAN COAST NEAR 28N13W AND A COLD FRONT EXTENDING SW FROM THE TRIPLE POINT TO 22N28W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING MAINLY NEAR THE LOW CENTER WITHIN 240 NM OF THE LOW CENTER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN