000 AXNT20 KNHC 181116 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST WED FEB 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... ...GALE WARNING FOR THE W ATLC... A GALE WARNING IS IN EFFECT N OF 28.5N WITHIN 90 NM SE OF A COLD FRONT OVER THE SOUTHWESTERN N ATLC. THE GALE FORCE WINDS ARE FORECAST TO SHIFT EAST AHEAD OF THE EASTWARD ADVANCING COLD FRONT UNTIL 0600 UTC THURSDAY...WHEN WINDS ARE EXPECTED TO DECREASE BELOW GALE FORCE. PLEASE SEE THE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS. ...GALE WARNING FOR THE GULF OF MEXICO... A GALE WARNING IS IN EFFECT S OF 21N W OF 95W ASSOCIATED WITH THE TIGHT PRESSURE GRADIENT BEHIND THE COLD FRONT PRESENTLY ACROSS THE GULF. THE GALE WINDS ARE FORECAST TO DIMINISH TO BELOW GALE FORCE AT 1800 UTC TODAY. PLEASE SEE THE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC NEAR 07N12W TO 03N20W WHERE THE ITCZ BEGINS AND CONTINUES TO S OF THE EQUATOR AT 26W TO THE COAST OF S AMERICA NEAR 2S45W. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM OF THE ITCZ AXIS W OF 16W. ...DISCUSSION... GULF OF MEXICO... A STRONG UPPER TROUGH IS SWINGING EASTWARD ACROSS THE NORTHERN GULF. THIS TROUGH SUPPORTS A COLD FRONT THAT EXTENDS ACROSS CENTRAL FL NEAR 28N82W AND ACROSS THE GULF TO 24N88W TO THE COAST OF MEXICO NEAR 18N93W. SCATTERED TO NUMEROUS SHOWERS ARE WITHIN 90 NM OF EITHER SIDE OF THE COLD FRONT. A PRE-FRONTAL SURFACE TROUGH EXTENDS ACROSS S FL NEAR 25N81W AND OVER THE SE GULF TO 23N85W AND THEN OVER THE YUCATAN PENINSULA. SCATTERED MODERATE CONVECTION WITH THUNDERSTORMS ARE WITHIN 70 NM OF THE TROUGH AXIS. STRONG HIGH PRESSURE BUILDING ACROSS THE NW GULF IN THE WAKE OF THE COLD FRONT IS PRODUCING GALE FORCE WINDS OVER PORTIONS OF THE SW GULF. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. NORTHERLY WINDS AROUND 20 KT ARE N OF THE FRONT ELSEWHERE ACROSS THE GULF. THE COLD FRONT WILL CONTINUE TO MOVE SE AND WILL EXIT THE GULF TONIGHT. HIGH PRESSURE WILL THEN DOMINATE THE BASIN THROUGH THURSDAY. CARIBBEAN SEA... A LARGE UPPER LEVEL RIDGE CENTERED OVER CENTRAL AMERICA EXTENDS A RIDGE AXIS OVER THE CARIBBEAN BASIN TO HISPANIOLA AND OVER THE WESTERN ATLC. SUBSIDENCE FROM THE RIDGE IS SUPPORTING MAINLY FAIR WEATHER ACROSS THE MAJORITY OF THE BASIN THIS MORNING. A PRE-FRONTAL SURFACE TROUGH JUST NW OF THE EXTREME NW CARIBBEAN IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NW OF A LINE FROM 18N88W TO 22N83W. ISOLATED TRADE WIND SHOWERS ARE OVER THE BASIN E OF 73W. TRADE WINDS OF 20 TO 25 KT COVER THE EASTERN CARIBBEAN. SE WINDS OF 10 TO 15 KT COVER THE NW CARIBBEAN. THE PRE-FRONTAL SURFACE TROUGH WILL MOVE ACROSS THE NW CARIBBEAN THIS MORNING WITH CONVECTION. THE COLD FRONT OVER THE SE GULF OF MEXICO WILL ENTER THE NW CARIBBEAN TONIGHT. ...HISPANIOLA... ISOLATED TRADE WIND SHOWERS IN THE LOW LEVEL MOISTURE ARE OVER THE ISLAND THIS MORNING. ISOLATED SHOWERS WILL CONTINUE TO BE POSSIBLE THROUGH TONIGHT WITH AN INCREASE IN SHOWER ACTIVITY ON THURSDAY AS A COLD FRONT APPROACHES THE ISLAND FROM THE NW. ATLANTIC OCEAN... UPPER LEVEL RIDGING OVER THE WESTERN ATLC IS SHIFTING EASTWARD AS A DEEP TROUGH OVER THE US SLIDES EAST. THE UPPER TROUGH SUPPORTS A 1006 MB LOW OVER THE W ATLC NEAR 34N71W. A COLD FRONT EXTENDS SW FROM THE LOW TO CENTRAL FL NEAR 28N81W. SCATTERED TO NUMEROUS SHOWERS ARE WITHIN 90 NM OF THE FRONT. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 28N77W TO FL NEAR MIAMI AS OF 1200 UTC. SCATTERED MODERATE CONVECTION IS WITHIN 70 NM SE OF THE TROUGH. SCATTERED SHOWERS AND THUNDERSTORMS ARE WITHIN 70 NM NW OF THE TROUGH AXIS. GALE FORCE WINDS ARE OCCURRING E OF THE FRONT OVER THE W ATLC. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. TO THE EAST OF THE UPPER LEVEL RIDGE...AN UPPER TROUGH ALONG 43W SUPPORTS A DISSIPATING STATIONARY FRONT FROM 31N46W TO 27N52W. SCATTERED SHOWERS ARE POSSIBLE WITHIN 75 NM NW OF THE FRONT. A LARGE AREA OF HIGH PRESSURE CENTERED OVER FRANCE EXTENDS ACROSS THE EASTERN ATLC WITH ANTICYCLONIC FLOW AND GENERALLY FAIR WEATHER. OVER THE NEXT 24 HOURS THE COLD FRONT WILL MOVE E TO NEAR 30N72W TO THE BAHAMAS WITH SHOWERS AND ISOLATED THUNDERSTORMS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO