000 AXNT20 KNHC 160005 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAR 15 2015 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. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLANTIC NEAR 08N13W SW TO 03N18W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 01S30W TO THE COAST OF NORTHERN BRAZIL NEAR 02S42W. SCATTERED MODERATE CONVECTION IS FROM 04S-02N WEST OF 25W. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE HIGH PRESSURE DOMINATES FROM THE UPPER GREAT LAKES SW TO THE MIDDLE MISSISSIPPI VALLEY...ACROSS TEXAS WITH A RIDGE AXIS EXTENDING ACROSS EASTERN MEXICO. THIS BROAD RIDGE PROVIDES GENERALLY EASTERLY FLOW OF 5 TO 15 KT EAST OF A SURFACE TROUGH ANALYZED FROM 25N92W TO THE BAY OF CAMPECHE NEAR 18N93W. W OF THE TROUGH OR 93W WINDS ARE FROM THE N-NE AND RANGE FROM 15 TO 25 KT...HIGHEST OVER THE SW GULF. ALOFT...AN ELONGATED LOW CENTERED ON SOUTHERN BAJA CALIFORNIA ALONG WITH AN UPPER RIDGE ANCHORED OVER EASTERN NICARAGUA GENERATE A DIFFLUENT ENVIRONMENT. THIS ENVIRONMENT ALOFT ALONG WITH INFLOW OF LOW- LEVEL MOISTURE FROM THE CARIBBEAN SEA THAT FANS OUT ACROSS THE BASIN SUPPORT SCATTERED TO ISOLATED SHOWERS OVER THE NORTHERN BASIN N OF 25N AND WEST OF THE TROUGH AXIS. THE SURFACE TROUGH WILL CONTINUE TO DRIFT WESTWARD AND DISSIPATE TUESDAY MORNING WHILE RIDGING CONTINUES TO BUILD ACROSS THE BASIN. THE CARIBBEAN SEA... A LOW PRESSURE SYSTEM WITH ASSOCIATED COLD FRONT IS OVER THE WESTERN ATLC WHICH ACTED TO REDUCE THE PRESSURE GRADIENT ON THE ATLC AND THE CARIBBEAN...THIS RESULTING IN THE REDUCTION OF WINDS BELOW GALE FORCE ALONG THE COAST OF COLOMBIA. EASTERLY TO NORTHEASTERLY FLOW OF 20 TO 25 KT PREVAILS S OF 16N BETWEEN 70W AND 81W. TRADES OF 15 KT DOMINATE ELSEWHERE ACROSS THE BASIN. OTHERWISE...THE CARIBBEAN SEA HAS NO SURFACE FEATURES OF INTEREST NOR IS THERE ANY ORGANIZED DEEP CONVECTION. AN UPPER RIDGE CONTINUES TO COVER THE CARIBBEAN WHICH IS PROMOTING SUBSIDENCE OVER THE CARIBBEAN. EXCEPT FOR POSSIBLE RAINSHOWERS FOR HISPANIOLA AND PUERTO RICO ENHANCED BY A COLD FRONT OVER THE SW N ATLC AND A SURFACE TROUGH TO PASS N OF THESE ISLANDS ON TUE AND WED...LITTLE CHANGE IS EXPECTED DURING THE NEXT TWO DAYS. ...HISPANIOLA... GENERALLY FAIR SKIES ACROSS THE ISLAND AS DEEP LAYER DRY AIR CONTINUES TO DOMINATE IN THE REGION. WINDS ALONG THE COASTS WILL RANGE BETWEEN 10 TO 15 KT EAST-NORTHEAST. THESE CONDITIONS WILL PERSIST THROUGH MONDAY. A COLD FRONT AND A PRE-FRONTAL TROUGH FORECAST TO PASS CLOSE TO THE NORTHERN ISLAND TUE AND WED MAY ENHANCE SHOWERS. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW OVER THE NW ATLC SUPPORTS A BROAD LOW PRESSURE SYSTEM WITH AN ASSOCIATED COLD FRONT EXTENDING TO 30N72W SW TO 28N77W. MODERATE LOW-LEVEL MOISTURE IN THE FRONT VICINITY ALONG A DIFFLUENT ENVIRONMENT ALOFT GENERATED BY A RIDGE WITH AXIS NEAR 50W SUPPORT SCATTERED SHOWERS AND TSTMS AHEAD OF THE FRONT N OF 28N BETWEEN 69W AND 73W. AN ELONGATED UPPER TROUGH WITH AXIS NEAR 30W N OF 30N EXTENDS SW TO THE CENTRAL ATLC AND CONTINUES TO SUPPORT A SECOND COLD FRONT ALONG 30N32W TO 26N40W TO 22N48W. NO CONVECTION IS ASSOCIATED WITH THIS FEATURE. SURFACE RIDGING PREVAILS ELSEWHERE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR