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

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FXUS64 KMRX 240910
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
400 AM EST SAT JAN 24 2015

.SHORT TERM (TODAY AND TONIGHT)...-- Changed Discussion --UPPER TROUGH MOVING ACROSS THE
AREA WILL QUICKLY MOVE OFF TO THE EAST AND NORTHEAST. BAND OF LIGHT
PRECIP WILL EXIT THIS MORNING. PLATEAU AND HIGHER ELEVATION AREAS
IN SW VA AND EAST TENNESSEE MOUNTAINS STILL LOOK TO HAVE THE BEST
CHANCE FOR SIGNIFICANT ACCUMULATION OF SNOW...SO WILL LEAVE ADVISORY
AS IS FOR NOW. ELSEWHERE SHOULD SEE RAIN POSSIBLY MIXING WITH OR
CHANGING TO SNOW BEFORE ENDING...WITH LITTLE IN THE WAY OF
ACCUMULATION. ONLY A BRIEF SHOT OF COLD ADVECTION BEHIND THE
DEPARTING SYSTEM. LOOKS LIKE CLOUDS WILL CLEAR OUT AT LEAST SOUTH
AND CENTRAL THIS AFTERNOON...BUT MAY HAVE A HARDER TIME NORTH.
TONIGHT SHOULD BE DRY BUT STILL SOME CLOUDS EXPECTED ESPECIALLY
NORTH. MAV TEMPS GENERALLY LOOK REASONABLE SO WILL ONLY MAKE SOME
MINOR ADJUSTMENTS.

.LONG TERM (SUNDAY THROUGH FRIDAY)...MODEL FORECASTS CONTINUE TO
SHOW A MODERATELY STRONG SHORT WAVE TROUGH DROPPING SOUTHEAST OUT OF
THE WESTERN CANADIAN PROVINCES AND NORTHERN PLAINS TODAY INTO
TONIGHT WITH ARRIVAL OVER THE SOUTHERN APPALACHIANS MAINLY SUNDAY
AFTERNOON THROUGH ABOUT MID DAY MONDAY. WARM AIR ADVECTION AHEAD OF
THE FEATURE KEEPS PRECIPITATION MAINLY IN THE FORM OF RAIN DURING
THE DAY SUNDAY. BY EVENING...COLD AIR ADVECTION WILL BE EFFECTIVE
ENOUGH IN THE HIGHER TERRAIN...PRIMARILY ABOVE 3000 FEET FOR A
CHANGE OVER FROM RAIN TO SNOW OVER SOUTHWEST VIRGINIA AND THE
MOUNTAINS BORDERING WESTERN NORTH CAROLINA. HOWEVER...MODEL
FORECASTS ARE RESISTANT TO CHILLING DOWN THE LOW LEVEL AIRMASS
SUFFICIENTLY FOR MUCH OF THE GREAT VALLEY TO SEE MUCH IN THE WAY OF
SNOWFALL ACCUMULATION PRIOR TO DAYBREAK. 85H TEMPERATURES FINALLY
GET COLD ENOUGH FOR THE RAIN TO MIX WITH AND CHANGE TO SOME SNOW
ACROSS THE LOWER ELEVATIONS OF SOUTHWEST VIRGINIA AND EXTREME
NORTHEAST TENNESSEE AS WELL AS THE CUMBERLAND PLATEAU. STILL...SOME
OF THESE AREAS COULD SEE A CHANGE BACK TO A MIXTURE OF RAIN AND SNOW
BY LATE MORNING INTO THE AFTERNOON IN THESE LOWER ELEVATION LOCALES
WITH THE FREEZING LEVEL RISING BACK TO AROUND 1000 FEET WITH SOME
DIURNAL WARMING. THEREFORE...SOME LIGHT SNOW ACCUMULATION IS LIKELY
IN THE HIGHER TERRAIN WHERE AMOUNTS COULD REACH 1-2 INCHES ACROSS
PARTS OF SOUTHWEST VIRGINIA AND EXTREME NORTHEAST TENNESSEE WITH 2-4
INCH TOTALS POSSIBLE IN THE SMOKY MOUNTAINS BY LATE MONDAY AFTERNOON.

COLDER AIR SPILLS INTO THE FORECAST AREA MONDAY NIGHT INTO TUESDAY
AND THE MODELS CONTINUE TO INDICATE THE ARRIVAL OF ANOTHER...MUCH
WEAKER...IMPULSE. THIS FEATURE ALONG WITH SOME UPSLOPE FLOW SHOULD
GENERATE SOME LIGHT SNOW ACROSS THE ENTIRE FORECAST AREA.
HOWEVER...DUE TO THIS SYSTEM`S LACK OF LIFTING ABILITIES AND LIMITED
MOISTURE DEPTH...SNOWFALL AMOUNTS COULD BE RATHER LIGHT IN THE LOWER
ELEVATIONS. IN THIS NORTHWEST FLOW SCENARIO THE BETTER CHANCE OF
EFFECTIVE SNOW WOULD AGAIN BE IN THE HIGHER TERRAIN...MAINLY ACROSS
SOUTHWEST VIRGINIA AND IN THE MOUNTAINS BORDERING NORTH CAROLINA.
THE MEAN EASTERN STATES UPPER TROUGH FINALLY MOVES AWAY ON WEDNESDAY
ALLOWING A RETURN TO SOME SUNSHINE. HOWEVER...ANY NOTICEABLE WARMING
MAY NOT BE IN THE WORKS UNTIL ABOUT THURSDAY...BUT IN ORDER TO ENJOY
SLIGHTLY WARMER TEMPERATURES WE WILL HAVE TO CONTEND WITH ANOTHER
CHANCE FOR RAIN AROUND THE THURSDAY THROUGH FRIDAY TIME FRAME WTIH
THE ARRIVAL OF ANOTHER FRONTAL SYSTEM.-- End Changed Discussion --

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --CHATTANOOGA AIRPORT, TN 46 32 54 36 / 20 0 50 30
KNOXVILLE MCGHEE TYSON AIRPORT, TN 43 31 50 35 / 40 10 40 60
OAK RIDGE, TN 44 31 50 35 / 30 10 50 60
TRI CITIES AIRPORT, TN 41 27 50 34 / 70 10 50 70-- End Changed Discussion --

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR BLOUNT
SMOKY MOUNTAINS-CAMPBELL-CLAIBORNE-COCKE SMOKY MOUNTAINS-
JOHNSON-MORGAN-SCOTT TN-SEVIER SMOKY MOUNTAINS-SOUTHEAST
CARTER-SOUTHEAST GREENE-UNICOI.

VA...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR LEE-
RUSSELL-WISE.

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