Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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000 FXUS64 KMRX 291844 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 244 PM EDT MON SEP 29 2014 .SHORT TERM /TONIGHT AND TUESDAY/... CLOUDS ARE SLOWLY BEGINNING TO BREAK UP FROM WEST TO EAST AS A WEAK UPPER-LEVEL DISTURBANCE CLEARS THE AREA. AS OF MID-AFTERNOON ALL BUT FAR NORTHEAST TENNESSEE AND THE EAST TENNESSEE MOUNTAINS AND FOOTHILLS HAVE BECOME MOSTLY TO PARTLY SUNNY. THIS HAS ALLOWED THE MERCURY TO CLIMB UP INTO THE UPPER 70S TO AROUND 80 DEGREES ALONG THE PLATEAU AND PORTIONS OF THE SOUTHERN/CENTRAL VALLEYS. THIS CLEARING WILL CONTINUE THROUGH THE LATE AFTERNOON AND EVENING...RESULTING IN A MOSTLY CLEAR SKY FOR THE FORECAST AREA LATER TONIGHT. THOUGH MOST LOCATIONS DID NOT RECEIVE MUCH IN THE WAY OF RAINFALL...A MOIST BOUNDARY LAYER COMBINED WITH THE CLEAR/CALM CONDITIONS WILL RESULT IN WIDESPREAD PATCHY FOG DEVELOPMENT /SOME PERHAPS LOCALLY DENSE AROUND DAYBREAK/. AS SUCH...HAVE MAINTAINED THIS IN THE ZONES...AND MAY NEED TO MONITOR THE POSSIBILITY OF A DENSE FOG ADVISORY LATER THIS EVENING SHOULD CONDITIONS BECOME APPARENT THAT IS IT WARRANTED. FOR TUESDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN AND PROMOTE MOSTLY SUNNY AND DRY CONDITIONS. THIS ABUNDANT SUNSHINE ALONG WITH INCREASED THICKNESS VALUES/TEMPERATURES ALOFT WILL ALLOW FOR WIDESPREAD HIGHS IN THE LOWER 80S BY THE LATE AFTERNOON ACROSS THE CENTRAL/SOUTHERN VALLEYS...WITH UPPER 70S EXPECTED OVER SOUTHWEST VIRGINIA. .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE WILL BE OVER THE SOUTHEAST CONUS TO START THE PERIOD...THEN THE HIGH WILL SHIFT EASTWARD TO THE COAST ON THURSDAY. ABOVE NORMAL TEMPS CAN BE EXPECTED BOTH DAYS UNDER MOSTLY SUNNY SKIES. A S-SW FLOW WILL ADVECT MOISTURE INTO THE AREA BEGINNING THURSDAY...WITH PRECIP DEVELOPING NRN AL/GA IN THE AFTERNOON. STRONG LIFT ASSOCIATED WITH THE UPPER JET ENTRANCE REGION AND POTENT 500 MB VORT MAX WILL BRING LIKELY POPS AND A CHANCE OF THUNDERSTORMS LATE THURSDAY NIGHT INTO FRIDAY MORNING. WHILE FORCING SHOWN BY THE GFS LOOKS STRONG...OVERNIGHT TIMING AND LACK OF INSTABILITY SHOULD PROBABLY MEAN A LOW THREAT OF SEVERE. THE ECMWF IS A BIT FASTER THAN THE GFS TO MOVE OUT PRECIP...AND THE LATEST GFS CONTINUES TO TREND FASTER FROM PREVIOUS RUNS...SO WILL TREND POPS DOWNWARD A LITTLE FASTER THAN PREVIOUSLY FORECAST...ENDING FRIDAY NIGHT. SURFACE HIGH PRESSURE AND A BROAD UPPER TROUGH WILL PROVIDE A COOL AND DRY AIR MASS FOR THE WEEKEND...WITH HIGHS IN THE 60S TO LOWER 70S AND LOWS IN THE 40S TO LOWER 50S. THE GFS BRINGS A WEAK DISTURBANCE IN THE NW FLOW NEAR OUR NORTHERN SECTIONS ON MONDAY...BUT CONFIDENCE IS LOW THAT THIS WILL ACTUALLY OCCUR...SO WILL GO DRY ON MONDAY WITH TEMPS REBOUNDING TO NEAR NORMAL. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 59 84 59 84 / 10 10 10 10 KNOXVILLE MCGHEE TYSON AIRPORT, TN 58 82 57 82 / 10 10 0 0 OAK RIDGE, TN 58 83 56 82 / 10 10 0 0 TRI CITIES AIRPORT, TN 54 80 50 81 / 10 10 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ AMP/DGS

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