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

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
397 FXUS64 KMRX 120816 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 316 AM EST FRI FEB 12 2016 .SHORT TERM...(TODAY AND TONIGHT)...RADAR SHOWS INCREASING RETURNS TO OUR WEST AS WEAK SHORT WAVE APPROACHES. THIS FEATURE WILL SWING ACROSS THE AREA TODAY...WITH LIGHT PRECIP EXPECTED ACROSS AT LEAST NORTHERN HALF OF THE AREA. TEMP PROFILES INDICATE MOSTLY SNOW AT THE ONSET...POSSIBLY MIXING WITH RAIN MOSTLY AROUND AND SOUTH OF I40 CORRIDOR. SNOWFALL AMOUNTS LOOK ON THE LIGHT SIDE BUT ENOUGH TO CAUSE SOME TRAVEL PROBLEMS SO WINTER WEATHER ADVISORY LOOKS REASONABLE. WILL ADD A FEW COUNTIES ON SOUTH SIDE OF THE CURRENT ADVISORIES FOR TODAY. NORTHWEST FLOW TONIGHT WITH COLD ADVECTION AND SOME ADDITIONAL SNOW SHOWERS ESPECIALLY NORTH AND MOUNTAINS. WILL ADD SMOKY MOUNTAINS TO THE ADVISORY THROUGH TONIGHT AS EXPECT SOME ADDITIONAL ACCUMULATION THERE AS WELL. WIND CHILLS MAY REACH ADVISORY CRITERIA IN SOME OF THE HIGHER TERRAIN LATE TONIGHT...BUT CURRENT NUMBERS LOOK BORDERLINE EXCEPT HIGHEST PEAKS SO WILL HOLD OFF ON ANY WIND CHILL ADVISORY FOR NOW. BUT WILL MENTION IN HWO. .LONG TERM...(SATURDAY THROUGH THURSDAY)...WINTER CONTINUES FOR THE EASTERN U.S. THROUGH MOST OF THE LONG TERM PERIOD WITH A MEAN UPPER TROUGH HANGING AROUND UNTIL THROUGH WEDNESDAY WITH SOME HOPE FOR A RIDGE ON THE WEEKEND HORIZON. MORE COLD AIR SPILLS INTO THE REGION ON PREVAILING NORTHERLY FLOW ON SATURDAY BUT AT LEAST IT SHOULD BE PRECIPITATION FREE. SUNDAY WILL BE A TRANSITION DAY WITH GENERALLY DRY CONDITIONS THROUGH MUCH OF THE DAYTIME PERIOD. HOWEVER...THE UPPER FLOW AMPLIFIES WITH A RESPECTABLE SHORT WAVE DEVELOPING OVER THE LOWER MISSISSIPPI VALLEY LATE SUNDAY NIGHT INTO MONDAY. WARM AND MOIST ADVECTION GETS GOING AHEAD OF THIS FEATURE SUNDAY NIGHT INTO EARLY MONDAY MORNING OVER THE TOP OF SUBFREEZING SURFACE AIR MASS SO HAVE TO KEEP WINTRY PRECIPITATION IN THE WORKS HERE. ON MONDAY A HEALTHY SURFACE LOW WILL BE PASSING ACROSS THE SOUTHEAST CORNER OF THE FORECAST AREA AND THE MODEL FORECASTS BRING SUFFICIENT WARMING INTO THE REGION TO CHANGE PRECIPITATION BACK TO RAIN OVER MUCH OF THE REGION. AS THE LOW HEADS EAST THROUGH THE MIDDLE ATLANTIC THE SUB-FREEZING AIR FILLS BACK IN BEHIND THE DEPARTING LOW CHANGING PRECIP BACK TO SNOW BEFORE ENDING SOMETIME TUESDAY MORNING. IT GOES WITHOUT SAYING TRYING TO PREDICT EXACTLY WHERE THE "CHANGE OF STATE" WITH RESPECT TO WATER WILL BE EXACTLY (GEOGRAPHICALLY)...AT THIS POINT IN TIME...IS CHALLENGING WITH CERTAIN MODEL ADJUSTMENTS TO THE STRENGTH AND POSITION OF THE SHORT WAVE TROUGH AND ASSOCIATED SURFACE PRESSURE PATTERN IN THE NEXT COUPLE OF DAYS. ADDITIONALLY IT IS DIFFICULT TO SAY WHAT IMPACT THE TRAILING ALBERTA CLIPPER MAY HAVE ON THE SOUTHERN APPALACHIANS BUT THE MODELS DEPICT THIS FEATURE BUILDING INTO THE AREA MAINLY TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM WOULD PRODUCE SNOW SHOWERS DUE TO THE EXTENDED PERIOD OF COLD AIR ADVECTION PRIOR TO ITS ARRIVAL. THE FEATURE MOVES AWAY WEDNESDAY NIGHT ALLOWING A DRY THURSDAY WITH THE HOPE OF WARMER AIR HEADING INTO THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 49 24 34 19 / 20 10 0 0 KNOXVILLE MCGHEE TYSON AIRPORT, TN 41 20 28 15 / 50 10 10 0 OAK RIDGE, TN 42 20 30 14 / 60 10 0 0 TRI CITIES AIRPORT, TN 36 19 24 9 / 80 20 10 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR CAMPBELL-CLAIBORNE-GRAINGER-HAMBLEN-HANCOCK-HAWKINS- JEFFERSON-MORGAN-NORTHWEST CARTER-NORTHWEST COCKE-NORTHWEST GREENE-SCOTT TN-SULLIVAN-UNION-WASHINGTON TN. WINTER WEATHER ADVISORY UNTIL 4 AM EST SATURDAY FOR BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-JOHNSON-SEVIER SMOKY MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST GREENE-UNICOI. VA...WINTER WEATHER ADVISORY UNTIL 4 AM EST SATURDAY FOR LEE-RUSSELL- SCOTT-WASHINGTON-WISE. && $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.