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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS64 KMRX 151915
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
315 PM EDT SAT MAR 15 2014

.SHORT TERM (TONIGHT THROUGH MONDAY)...
AS A LOW PRESSURE SYSTEM DEVELOPS OVER THE SOUTHERN PLAINS AND
TRACKS EAST...ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL BE SPREADING
CLOUDS INTO SOUTHERN PORTIONS OF THE AREA THIS EVENING. STRONGER
FORCING IN THE 850 MB CONVERGENCE ZONE AND UPPER DIFFLUENCE IN THE
JET EXIT REGION WILL PROVIDE MODERATE PRECIP BEGINNING IN THE 09-12Z
WINDOW...AND SPREAD NORTHWARD THROUGH THE MORNING.

THE NAM AND GFS CONTINUE TO HAVE DIFFERENCES WITH REGARD TO THE
TIMING OF THE EXITING LIFT/MOISTURE SUNDAY EVENING...WITH THE GFS
BEING FASTER. IT PUTS US FIRMLY IN THE DRY SLOT BETWEEN 21-
00Z...LEAVING ONLY DRIZZLE OR VERY LIGHT RAIN. NAM SHOWS SOME DRYING
ALOFT OCCURRING AFTER 00Z...BUT NOT AS DRAMATICALLY AS THE GFS. WILL
LEAN TOWARD THE GFS AND TREND POPS DOWNWARD AFTER 21Z...BUT STAY IN
THE LIKELY RANGE WITH LOW QPF AMOUNTS THROUGH SUNDAY NIGHT. A TROWAL
FEATURE APPEARS IN THE NAM AND GFS SUNDAY NIGHT...WHICH MAY INCREASE
PRECIP AMOUNTS AGAIN IN THE 06Z-12Z WINDOW ACROSS NORTHERN AREAS.

ALSO DURING THIS TIME...THE NAM RAPIDLY COOLS THE 1000-850 MB LAYER
ON THE NW SIDE OF THE 850 MB LOW CENTER...SUGGESTING A PERIOD OF
SLEET/FZRA IN SW VA AND THE NORTHERN PLATEAU AREA. THE GFS IS
PROFILE WARMER INITIALLY...BUT STILL DROPS BELOW FREEZING IN THIS
LAYER BRIEFLY AROUND 12Z. WILL ADD A CHANCE OF SLEET TO THE PLATEAU
AND PARTS OF SW VA. IF THE NAM IS CORRECT...ACCUMULATIONS WILL BE
POSSIBLE...BUT WILL NOT ISSUE ANY ADVISORIES AT THIS TIME AS
CONFIDENCE IS LOW AND STILL 36+ HOURS OUT.

MOISTURE DEPTH DECREASES RAPIDLY MONDAY MORNING...AND LIFT IS WEAK
AT THIS TIME...WHICH SHOULD LOWER POPS TO JUST A LOW TO SLIGHT
CHANCE IN THE AFTERNOON.

.LONG TERM (MONDAY NIGHT THROUGH SATURDAY)... MOISTURE LINGERS
MONDAY NIGHT AS BACK EDGE OF SYSTEM SLOWLY MOVES UP THE EAST COAST.
AS TEMPERATURES COOL MONDAY NIGHT MIXTURE OF SLEET OR A LITTLE
LIGHT SNOW POSSIBLE NE TN AND SW VA AS SYSTEM DEPARTS. SNOW OR
POSSIBLY SLEET AMOUNTS EXPECTED TO BE VERY LIGHT SO DID NOT ADD ANY
TO SNOWFALL GRIDS. LOWS MONDAY NIGHT MOSTLY UPPER 30S TO NEAR 40
BUT LOWER 30S NORTHEAST SECTIONS. TUESDAY WEAK HIGH PRESSURE BUILDS
IN FROM THE WEST AND AT THE SAME TIME SURFACE LOW DEVELOPS OVER THE
CENTRAL PLAINS. CLOUDS MAYBE SLOW TO MOVE OUT BUT HIGHS WARM TO THE
LOWER 50S TO LOWER 60S. SOUTHWEST WINDS MAY INCREASE AS SURFACE LOW
DEVELOPS TO THE NW BY TUESDAY NIGHT. NORTHERN SYSTEM MOVING THROUGH
THE GREAT LAKES TUESDAY NIGHT AND WEDNESDAY WILL BRING SOME CLOUDS
INTO THE FORECAST AREA WEDNESDAY WITH MUCH WARMER
TEMPERATURES...MOSTLY 60S AND A CHANCE OF SHOWERS WEDNESDAY NIGHT.
AFTER THIS SYSTEM PULLS OUT EARLY THURSDAY ANOTHER TRANQUIL PERIOD
THROUGH FRIDAY WITH BUILDING HIGH PRESSURE. STRONGER SYSTEM MOVES
IN SATURDAY. SHOWERS AGAIN POSSIBLE...THUNDER MAY HAVE TO BE ADDED
LATER IF LATER RUNS SHOW STRENGTHENING OF THIS SYSTEM.


&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             71  51  56  46 /   0 100 100  70
KNOXVILLE MCGHEE TYSON AIRPORT, TN  67  48  55  41 /   0  70 100  70
OAK RIDGE, TN                       69  47  51  38 /   0  80 100  80
TRI CITIES AIRPORT, TN              68  40  49  37 /   0  20 100  80

&&

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

$$

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