National Weather Service Text Product Display

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

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

-- Highlight Changed Discussion --

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS64 KMRX 231920
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
320 PM EDT THU MAY 23 2013

.SHORT TERM (TONIGHT AND FRIDAY)...-- Changed Discussion --CURRENT SURFACE ANALYSIS SHOWS A
WEAK COLD FRONT GENERALLY ALONG THE CUMBERLAND PLATEAU...WITH RADARS
REVEALING SCATTERED CONVECTION DEVELOPING OVER EASTERN KY AND
SOUTHWEST VA. A MARGINALLY UNSTABLE AIR MASS WILL CONTINUE OVER THE
FORECAST AREA INTO THIS EVENING...AS A BROAD UPPER-LEVEL TROUGH
AMPLIFIES OVER THE EASTERN HALF OF THE NATION. MODELS INDICATE THAT
THIS UPPER TROUGH WILL CONTINUE TO PRODUCE SCATTERED SHOWERS AFTER
MIDNIGHT...WITH MUCH COOLER AND DRIER AIR MOVING INTO THE FORECAST
AREA BEHIND THE FRONTAL BOUNDARY ON FRIDAY. AS FOR TEMPS...GFS AND
NAM GUIDANCE NUMBERS ARE IN GENERAL AGREEMENT FOR TONIGHT AND
FRIDAY...BUT WILL COMPROMISE WHERE SOME SLIGHT DIFFERENCES ARE NOTED.

.LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)...HIGH PRESSURE IN NW
FLOW PATTERN TO DROP TEMPERATURES MUCH BELOW NORMAL FRIDAY NIGHT
WITH FROST POSSIBLE NE SECTIONS AND NORTHERN AND CENTRAL MOUNTAINS.
SW NORTH CAROLINA VALLEYS COULD ALSO DROP TO UPPER 30S. REFERRED TO
FROST IN HAZARDOUS WEATHER OUTLOOK AND COULD ISSUE AN ADVISORY AS
EARLY AS FRIDAY MORNING IF CONFIDENCE IS HIGH. WILL GENERALLY FOLLOW
COOLER MAV NUMBERS FRIDAY NIGHT. SATURDAYS HIGHS ONLY A FEW DEGREES
WARMER THAN FRIDAY AS SURFACE HIGH MOVES SOUTHEAST FROM THE UPPER
MIDWEST INTO THE EASTERN GREAT LAKES AND OHIO AND TENNESSEE VALLEYS.
STILL SLIGHT COLD AIR ADVECTION WITH NORTHERLY FLOW. DEW POINTS WILL
BE IN THE 30S TO LOWER 40S WHICH WILL KEEP RH VALUES LOW FOR THIS
TIME OF YEAR. UPPER RIDGE OVER THE CENTRAL STATES SATURDAY BEGINS TO
SHIFT EAST WITH MOISTURE RETURNING TO THE MID MS VALLEY AS WESTERN
PART OF COLD FRONT MOVES BACK NORTH AS WARM FRONT. WITH FLOW AROUND
THE RIDGE CLOUDS BEGIN TO INCREASE SUNDAY AND SUNDAY NIGHT SHORTWAVE
ENERGY MOVING AROUND RIDGE AND INCREASED MOISTURE WILL BRING CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE REGION MAINLY AFTERNOON AND
EVENINGS MONDAY AND TUESDAY AND TO A LESSER EXTENT WEDNESDAY AND
THURSDAY AS RIDGE STRENGTHENS OVER THE GULF COAST AND TN VALLEY.
TEMPERATURES WILL BE ON A SLOW WARMING TREND AS WARMER AIR FROM
RIDGE SETTLES OVER THE TN VALLEY. LOWS WILL RISE BACK TO THE MID 50S
TO LOWER 60S TUESDAY THROUGH THURSDAY WITH HIGHS BACK TO THE UPPER
70S TO LOWER 80S NORTH AND LOWER TO MID 80S SOUTH.-- End Changed Discussion --
&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --CHATTANOOGA AIRPORT, TN 56 74 46 78 50 / 20 0 0 0 0
KNOXVILLE AIRPORT, TN 54 70 43 75 49 / 30 0 0 0 0
OAK RIDGE, TN 54 69 42 74 48 / 30 0 0 0 0
TRI CITIES AIRPORT, TN 51 66 35 72 42 / 30 0 0 0 10-- End Changed Discussion --
&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

DMG/TD

National Weather Service National Headquarters