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

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FXUS64 KMRX 030755
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
355 AM EDT TUE MAY 3 2016

.SHORT TERM (TODAY AND TONIGHT)...FRONTAL BOUNDARY IS MOVING SLOWLY
EAST ACROSS THE REGION EARLY THIS MORNING AND WILL BE OVER WESTERN
NORTH CAROLINA BY THIS AFTERNOON. PLENTY OF WRAP-AROUND MOISTURE
AND INSTABILITY FOR RE-DEVELOPMENT OF SHOWERS AND ISOLATED THUNDER
EAST OF INTERSTATE 75 THIS AFTERNOON.

FOR TONIGHT...PLENTY OF BOUNDARY LAYER MOISTURE REMAINS...
ESPECIALLY NORTHEAST SECTIONS. SHOWERS WILL DIMINISH...BUT WILL
REMAIN POSSIBLE NEAR OROGRAPHIC LIFT AREAS. OVERALL...WILL TREND
TOWARD A SLOWER EROSION OF LOW-CLOUDS THROUGH THE FORECAST.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)...MODELS CONTINUE TO BE IN
DECENT AGREEMENT OVER THE LONG TERM. THE GENERAL THEME IS BELOW
AVERAGE TEMPS DUE TO A DEEP TROUGH SWINGING DOWN INTO THE FORECAST
AREA.

WEDNESDAY WE START THE PERIOD WITH THE UPPER TROUGH JUST STARTING
DIG INTO THE AREA WITH THE CENTER OF LOW PRESSURE UP ACROSS THE
GREAT LAKES REGION. BY WEDNESDAY AFTERNOON POP CHANCES INCREASE AS
300 MB JET SWINGS IN WITH ADVANCING TROUGH PROVIDING GOOD DIVERGENCE
ACROSS THE REGION. DIVERGENCE...INCREASE IN MOISTURE...COLD
FRONT...AND STRONG VORTICITY ASSOCIATED WITH UPPER LEVEL LOW ARE ALL
FACTORS THAT WILL LEAD TO THE INCREASE IN POP CHANCES. WE ARE
SLIGHTLY UNSTABLE DURING THE AFTERNOON HOURS WITH A FEW HUNDRED
JOULES OF CAPE SO WILL HAVE THUNDER IN FORECAST. CENTER OF THE LOW
SINKS SOUTH WEDNESDAY NIGHT AS TROUGH REALLY DIGS IN WHICH WILL
BRING UNSEASONABLE COLD AIR INTO THE REGION. LOWS WEDNESDAY NIGHT
WILL BE 5 TO 10 DEGREES BELOW NORMAL. WITH THIS SURGE OF COLD AIR
THE HIGHEST ELEVATIONS COULD SEE SOME LIGHT SNOW SHOWERS
OVERNIGHT...WITH LITTLE TO NO ACCUMULATION EXPECTED.

THURSDAY WE WILL BE IN A POST FRONTAL AIR MASS BUT WRAP AROUND
MOISTURE WILL BEGIN TO RE-ENTER OUR NORTHERN AREAS AS THE CENTER OF
THE LOW IS LOCATED ACROSS THE VIRGINIAS. WRAP AROUND
MOISTURE...STRONG VORTICITY FIELD...AND GOOD UPPER LEVEL DIVERGENCE
WILL LEAD TO ANOTHER ROUND OF SHOWERS THROUGHOUT THE DAY. HAVE A
PRETTY TIGHT GRADIENT FOR POP CHANCES AS THE BEST MOISTURE EXISTS
ACROSS NETN AND SWVA. LIKELY POPS EXIST IN THESE AREAS WITH NO
CHANCE OF POPS ACROSS THE FAR SOUTHERN VALLEY. THURSDAY WILL BE OUR
COLDEST DAY OF THE LONG TERM WITH HIGHS STRUGGLING TO HIT 50 ACROSS
SWVA...MID 50S NETN....NEAR 60 CENTRAL VALLEY...MID 60S SOUTHERN
VALLEY. FOR MOST PLACES HIGHS WILL BE AROUND 15 DEGREES BELOW NORMAL
BUT AS MUCH AS 20 DEGREES ACROSS NETN AND SWVA. POP CHANCES HOLD IN
PLACE ACROSS NETN AND SWVA OVERNIGHT THURSDAY AS THE LOW CONTINUES
TO PULL IN MOISTURE ON THE BACK SIDE. ANOTHER CHANCE OF A LIGHT SNOW
SHOWER AGAIN POSSIBLE ACROSS THE HIGHEST PEAKS OVERNIGHT...WITH
LITTLE TO NO ACCUMULATION.

TEMPS WARM BY ABOUT 10 DEGREES ON FRIDAY AS THE LOW BEGINS TO MOVE
OFF TO OUR NE. MOSTLY PRECIP FREE FRIDAY AS MOISTURE EXITS WITH THE
LOW. HIGH PRESSURE BUILDS IN BRIEFLY ON SATURDAY AND TEMPS WILL BE A
FEW DEGREES ABOVE NORMAL. ANOTHER UPPER LEVEL TROUGH AND ASSOCIATED
COLD FRONT APPROACHES ON SUNDAY BUT JUST BRUSHES OUR REGION. THE GFS
AND ECMWF KEEP THE FRONT JUST TO OUR NORTH...SO WILL ONLY INCLUDE
SLIGHT CHANCE POPS ACROSS OUR NORTHERN MOST AREAS. FRONT REMAINS
STALLED TO OUR NORTH MONDAY WITH HIGH PRESSURE TRYING TO BUILD BACK
IN.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             73  51  71  48 /  20  10  40  40
KNOXVILLE MCGHEE TYSON AIRPORT, TN  69  50  67  46 /  30  10  60  50
OAK RIDGE, TN                       70  51  68  46 /  20  10  60  50
TRI CITIES AIRPORT, TN              71  49  65  44 /  50  30  60  60

&&

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

$$





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