000 AXNT20 KNHC 232344 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE APR 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SIERRA LEONE NEAR 9N13W INTO THE EASTERN TROPICAL ATLC ALONG 3N20W 2N33W. THE ITCZ BEGINS NEAR 2N33W AND CONTINUES ALONG EQ36W 3S42W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 3N-5N BETWEEN 11W-14W. SIMILAR ACTIVITY IS FROM 1N-5N BETWEEN 21W-25W...AND FROM EQ-4N BETWEEN 29W-33W. ...DISCUSSION... GULF OF MEXICO... MOSTLY DRY AIR ALOFT IS ACROSS THE GULF OF MEXICO AROUND AN UPPER LEVEL RIDGE WITH AXIS ALONG 90W. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH OVER SOUTH CAROLINA. THIS PATTERN IS PROVIDING EAST TO SOUTHEAST SURFACE FLOW OF 10- 15 KT. MOSTLY CLEAR SKIES ARE ALSO ACROSS THE AREA. THE SURFACE RIDGE IS EXPECTED TO SHIFT EAST OVER THE NEXT 24 HOURS AS A COLD FRONT MOVES OFF THE COAST OF TEXAS TOMORROW MORNING. THE FRONT WILL WEAKEN OVER THE SECOND HALF OF THE WEEK WITH SURFACE RIDGING REBUILDING ACROSS THE BASIN BY FRIDAY AND OVER THE WEEKEND. CARIBBEAN SEA... DRY AIR ALOFT IN MAINLY WESTERLY FLOW ALOFT IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF THE CARIBBEAN. ISOLATED SHOWERS ARE POSSIBLE ACROSS EASTERN CUBA...HISPANIOLA...AND PUERTO RICO WITH SIMILAR ACTIVITY EXTENDING FROM 12N-14N BETWEEN 61W-68W. THE ACTIVITY NEAR CUBA AND HISPANIOLA MAY BE ASSOCIATED WITH A WEAK SURFACE TROUGH NORTH OF CUBA. THE TROUGH IS EXPECTED TO SHIFT EAST OVER THE NEXT COUPLE OF DAYS BUMPING UP THE CHANCE OF PRECIPITATION OVER THE CENTRAL AND THEN EASTERN CARIBBEAN. TRADEWIND FLOW OF 10-15 KT DOMINATES THE MAJORITY OF THE CENTRAL AND EASTERN CARIBBEAN. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS BESIDES THE EASTWARD MOVEMENT OF MOISTURE ACROSS THE NORTHERN ISLANDS. ATLANTIC OCEAN... A NARROW UPPER LEVEL TROUGH COVERS THE WEST ATLC ALONG 74W. IT SUPPORTS A 1008 MB SURFACE LOW OFF THE MID- ATLC COAST NEAR 37N71W. A COLD FRONT EXTENDS FROM THE LOW CENTER ENTERING THE DISCUSSION AREA NEAR 32N72W AND CONTINUING TO 26N77W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS EXTEND UP TO 250 NM EAST OF THE FRONT. A WEAK SURFACE TROUGH EXTENDS TO THE SOUTH ALONG 26N76W TO 22N76W SUPPORTING A FEW ISOLATED SHOWERS OVER THE NORTHERN CARIBBEAN. AN UPPER LEVEL RIDGE IS TO THE EAST ALONG 60W SUPPORTING A SURFACE RIDGE ANCHORED BY A 1043 MB HIGH NEAR 46N52W. THE SURFACE RIDGE IS PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE WEST ATLC AND INTO THE CENTRAL ATLC. ANOTHER UPPER TROUGH IS ACROSS THE EASTERN ATLC NEAR 32W SUPPORTING A 1004 MB SURFACE LOW NEAR 35N33W. A COLD FRONT EXTENDS FROM THE LOW CENTER TO NEAR 29N35W 25N44W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. UPPER LEVEL RIDGING COVERS THE REMAINDER OF THE AREA ALONG 15W. BOTH FRONTAL SYSTEMS ARE EXPECTED TO MOVE EAST OF THE NEXT DAY OR SO. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON