000 AXNT20 KNHC 171052 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST TUE 17 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 CARIBBEAN... A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN FROM 11N-13N BETWEEN 74W-76W AND IS ASSOCIATED WITH THE TIGHT PRESSURE GRADIENT BETWEEN A SURFACE RIDGE OVER THE W ATLC AND LOWER PRESSURE OVER THE CARIBBEAN. THE WINDS WILL DROP BELOW GALE FORCE LATER THIS AFTERNOON. PLEASE SEE THE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...GALE WARNING FOR THE W ATLC... A GALE WARNING IS IN EFFECT FOR THE AREA N OF 30N W OF 77W AHEAD OF A COLD FRONT THAT IS CURRENTLY MOVING ACROSS THE GULF OF MEXICO. THIS GALE WARNING WILL SLIDE E ACROSS THE W ATLC AS THE FRONT MOVES E OVER THE W ATLC THROUGH WEDNESDAY MORNING. 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 WILL GO INTO EFFECT OVER THE SW GULF OF MEXICO FROM 19N-21N W OF 95W WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON ASSOCIATED WITH THE STRONG FRONT AND SURFACE RIDGE THAT WILL BUILD IN THE WAKE OF THE FRONT CURRENTLY MOVING ACROSS THE NW GULF OF MEXICO. 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 8N12W AND EXTENDS TO 1N18W WHERE THE ITCZ BEGINS AND CONTINUES S OF THE EQUATOR TO 2S30W AND INTO SOUTH AMERICA NEAR 39W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 4S-8N BETWEEN 15W-31W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGING COVERS THE GULF AS AN UPPER TROUGH MOVES E ACROSS TEXAS. THE UPPER TROUGH SUPPORTS LOW PRESSURE OVER GEORGIA WITH A COLD FRONT EXTENDING SW FROM THE LOW AND OVER THE GULF NEAR 30N86W TO THE MEXICO COAST NEAR 23N98W. NUMEROUS SHOWERS ARE WITHIN 160 NM NW OF THE COLD FRONT. THE COLD FRONT WILL MOVE QUICKLY SE AND WILL REACH CENTRAL FL AND THE SW GULF THIS EVENING. BY WEDNESDAY MORNING THE FRONT IS EXPECTED TO REACH THE FL STRAITS AND EXTEND TO THE YUCATAN WITH SHOWERS ONGOING ALONG AND NW OF THE FRONT. STRONG HIGH PRESSURE WILL BUILD ACROSS THE GULF BEHIND THE FRONT. THE TIGHT PRESSURE GRADIENT PRODUCED BETWEEN THE HIGH AND DEPARTING COLD FRONT WILL BRING GALE FORCE WINDS TO THE SW GULF WEDNESDAY MORNING. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. CARIBBEAN SEA... AN UPPER RIDGE DOMINATES THE CARIBBEAN WITH AN AXIS THAT EXTENDS N ACROSS CENTRAL CUBA TO OVER THE FLORIDA PENINSULA COVERING THE GULF OF MEXICO AND THE W ATLC. A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE W ATLC AND LOW PRESSURE OVER COLOMBIA IS PRODUCING GALE FORCE WINDS OVER PORTIONS OF THE SW CARIBBEAN. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. LOW LEVEL MOISTURE IN THE EASTERLY TRADE WINDS ARE SUPPORTING SCATTERED SHOWERS ACROSS THE LEEWARD ISLANDS...PUERTO RICO...AND OVER THE CENTRAL CARIBBEAN FROM 15N-19N BETWEEN 68W-81W. A COLD FRONT WILL ENTER THE NW CARIBBEAN WITHIN 36 HOURS AND WILL EXTEND FROM CENTRAL CUBA TO BELIZE BY WEDNESDAY EVENING. ...HISPANIOLA... LOW LEVEL MOISTURE IN TRADE WIND FLOW IS GENERATING SCATTERED SHOWERS ACROSS THE ISLAND. THIS MOISTURE WILL REMAIN ACROSS THE ISLAND THROUGH THE DAY TODAY. A COLD FRONT WILL BRING ADDITIONAL SHOWERS TO THE ISLAND ON THURSDAY. ATLANTIC OCEAN... SURFACE HIGH PRESSURE OF 1023 MB IS CENTERED NEAR 30N66W. AN UPPER TROUGH ALONG 51W SUPPORTS A COLD FRONT THAT EXTENDS THROUGH 32N45W TO 24N60W TO 23N65W WHERE IT TRANSITIONS TO A DISSIPATING STATIONARY FRONT TO 24N74W. SCATTERED SHOWERS ARE POSSIBLE WITHIN 50 NM OF THE FRONT. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 31N45W TO 24N54W TO THE VIRGIN ISLANDS NEAR 18N65W. SCATTERED MODERATE CONVECTION IS WITHIN 100 NM E OF THE TROUGH N OF 25N. S OF 25N...SCATTERED SHOWERS ARE WITHIN 50 NM SE OF THE TROUGH...AND WITHIN 120 NM NW OF THE TROUGH. RIDGING DOMINATES THE EASTERN ATLANTIC. GALE FORCE WINDS ARE OCCURRING OVER THE W ATLC AHEAD OF THE COLD FRONT CURRENTLY OVER THE GULF. THE FRONT WILL MOVE EAST OVER THE WESTERN ATLANTIC TUESDAY AFTERNOON AS GALE FORCE WINDS CONTINUE E OF THE FRONT. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO