000 AXNT20 KNHC 020000 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE JUL 01 2014 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. ...SPECIAL FEATURE... TROPICAL STORM ARTHUR IS LOCATED NEAR 27.8N 79.4W AT 2100 UTC OR ABOUT 85 NM N-NW OF FREEPORT GRAND BAHAMAS ISLAND. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. NUMEROUS STRONG CONVECTION AND TSTMS ARE FROM 25N-28N BETWEEN 77W-80W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 23N-29N BETWEEN 75W-81W. THE CENTER OF THE TROPICAL CYCLONE IS EXPECTED TO REMAIN JUST OFFSHORE AND MOVE EAST OF THE EAST-CENTRAL COAST OF FLORIDA DURING THE NEXT DAY OR SO. THE SYSTEM IS FORECAST TO PASS EAST OF NORTHEASTERN FLORIDA ON WEDNESDAY AND WEDNESDAY NIGHT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS LOCATED OVER THE EASTERN ATLC WITH THE AXIS EXTENDING FROM 10N28W TO 24N26W...MOVING W AT 15-20 KT. SAHARAN DRY AIR IS IN THE WAVE ENVIRONMENT EXCEPT SE OF ITS AXIS WHERE ISOLATED SHOWERS ARE OBSERVED. TROPICAL WAVE IS NEAR 500 NM E OF THE LESSER ANTILLES WITH AXIS EXTENDING FROM 21N51W TO 7N52W. THIS WAVE CAME OFF THE AFRICAN COAST AS A VERY LOW AMPLITUDE WAVE EMBEDDED IN THE ITCZ. AS THIS WAVE MOVED WESTWARD IT AMPLIFIED AND NOW IS IT EMBEDDED IN A SAHARAN DRY AIRMASS THAT IS HINDERING THE DEVELOPMENT OF CONVECTION. TROPICAL WAVE IS LOCATED IN THE CARIBBEAN WITH AXIS EXTENDING FROM 11N72W TO 20N70W MOVING W AT 10 KT. THIS WAVE IS BEING ACCOMPANIED BY A LOW-LEVEL BULGE OF MOISTURE THAT IS SUPPORTING NUMEROUS HEAVY SHOWERS AND TSTMS ACROSS HISPANIOLA AND ADJACENT WATERS. STRONG DEEP LAYER ENVIRONMENTAL SHEAR IS INHIBITING THE DEVELOPMENT OF CONVECTION ELSEWHERE ACROSS THE CENTRAL AND EASTERN CARIBBEAN. TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 8N81W TO 19N80W MOVING W AT 15 KT. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE IN THE SOUTHERN ENVIRONMENT OF THE WAVE S OF 13N W OF 80W WHERE DEEP LAYER MOISTURE IS PRESENT. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 11N15W TO 9N23W TO 7N29W. THE ITCZ BEGINS NEAR 7N29W AND CONTINUES ALONG 4N38W TO 4N51W. SCATTERED MODERATE CONVECTION IS FROM 5N- 13N BETWEEN E OF 28W. ...DISCUSSION... ...THE GULF OF MEXICO... MID-UPPER LEVEL RIDGING COVERS PORTIONS OF THE NORTHERN AND EASTERN GULF...THUS SUPPORTING A WEAK SURFACE HIGH OF 1016 MB SE OF LOUISIANA NEAR 28N89W. A MID-UPPER CYCLONIC CIRCULATION OVER THE WESTERN GULF ALONG ENHANCES LIFTING OF WARM MOIST AIR TO SUPPORT SCATTERED SHOWERS S OF 28N W 90W WHILE AN AREA OF UPPER DIFFLUENCE SUPPORT HEAVY SHOWERS AND TSTMS OVER THE NORTHERN YUCATAN PENINSULA. THE OUTER RAINBANDS OF TROPICAL STORM ARTHUR OVER THE SW N ATLC REACH THE EASTERN GULF WATERS E OF 86W WHERE SHOWERS AND TSTMS ARE NOTED. OTHERWISE...VARIABLE WINDS OF 5-10 KT COVER THE BASIN. THE CENTER OF HIGH PRESSURE WILL DRIFT NW TOWARDS TEXAS WITHIN THE NEXT 24 HOURS. A TROPICAL WAVE IS EXPECTED TO MOVE INTO THE BAY OF CAMPECHE BY THURSDAY MORNING. ...THE CARIBBEAN SEA... TWO TROPICAL WAVES ARE MOVING ACROSS THE CARIBBEAN WATERS. THE WESTERNMOST WAVE IS SUPPORTING CONVECTION IN THE SW BASIN WHILE A SECOND WAVE OVER THE CENTRAL BASIN IS GENERATING NUMEROUS SHOWERS AND TSTMS ACROSS HISPANIOLA. SEE THE TROPICAL WAVES SECTION FOR MORE INFORMATION. RAINSHOWERS AND TSTMS ARE ACROSS CUBA ASSOCIATED WITH TROPICAL STORM ARTHUR WHICH IS LOCATED NEAR 250 NM N OF THE ISLAND. DEEP LAYER DRY AIR IS OVER THE NW CARIBBEAN WHICH IS KEEPING THIS REGION DEVOID OF CONVECTION. EXCEPT FOR THE REGIONS OF CONVECTION AFOREMENTIONED...STRONG DEEP LAYER ENVIRONMENTAL SHEAR SUPPRESS THE DEVELOPMENT OF CONVECTION ELSEWHERE. THE WESTERNMOST WAVE IS EXPECTED TO ENTER THE BAY OF CAMPECHE THU MORNING WHILE THE SECOND WAVE WILL CONTINUE TO MOVE TOWARDS NICARAGUA WITH THE POTENTIAL OF GENERATING SHOWERS ALONG THE WAY. ...HISPANIOLA... HEAVY SHOWERS AND TSTMS ARE OVER THE ISLAND BEING GENERATED BY A TROPICAL WAVE WITH AXIS CURRENTLY ALONG WESTERN DOMINICAN REPUBLIC. THE WAVE IS EXPECTED TO MOVE OUT OF THE ISLAND LATE TONIGHT. SHOWERS ASSOCIATED WITH IT ARE EXPECTED TO CONTINUE THROUGH WEDNESDAY MORNING. ...THE ATLANTIC OCEAN... TROPICAL STORM ARTHUR IS OVER THE SW N ATLC GENERATING NUMEROUS HEAVY SHOWERS AND TSTMS ACROSS THE NORTHERN BAHAMAS AND ADJACENT WATERS. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. FARTHER EAST...AN UPPER LEVEL TROUGH BETWEEN 46W-70W IS SUPPORTING A 1015 MB LOW N OF THE AREA OF DISCUSSION FROM WHICH A SURFACE TROUGH EXTENDS ALONG 34N71W TO 30N66W TO 26N65W. SCATTERED SHOWERS ARE N OF 25N BETWEEN 65W-68W. THIS TROUGH ALOFT ALSO SUPPORTS A FRONTAL SYSTEM ANALYZED AS A COLD FRONT FROM 30N54W TO A 1016 MB LOW NEAR 29N56W TO 25N60W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 200 NM AHEAD OF THE FRONT. BESIDES THE TROPICAL WAVES DISCUSSED ABOVE...A 1032 MB HIGH NEAR THE AZORES EXTENDS A RIDGE TO N OF 24N E OF 51W. THE COLD FRONT IS EXPECTED TO TRANSITION TO A STATIONARY FRONT BY WED MORNING WHILE RIDGING WILL PREDOMINATE ELSEWHERE IN THE CENTRAL AND EASTERN ATLC. THE CENTER OF TROPICAL STORM ARTHUR WILL MOVE N OF THE AREA OF DISCUSSION BY LATE WED...HOWEVER RAINSHOWER ACTIVITY IS EXPECTED THROUGH LATE THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR