National Weather Service Text Product Display

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

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FXUS64 KMRX 201856
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
255 PM EDT MON MAY 20 2013

.SHORT TERM (TONIGHT AND TUESDAY)...THOUGH A FEW THUNDERSTORMS WILL
BE POSSIBLE TONIGHT OVER THE EAST TN MOUNTAINS...THE BULK OF THE
AREA WILL REMAIN DRY AS AN UPPER RIDGE CONTINUES TO BUILD IN.  ON
TUESDAY...WARM...MOIST AND WEAKLY UNSTABLE AIR OVER THE REGION WILL
WILL ALLOW FOR DIURNAL CONVECTION TO DEVELOP DURING THE AFTERNOON.
THIS ACTIVITY SHOULD INITIATE OVER HIGHER ELEVATIONS WITH ONLY A FEW
MOVING INTO THE VALLEY LATE IN THE DAY.

.LONG TERM (WEDNESDAY THROUGH MONDAY)...WETTEST PERIODS OF THE LONG
TERM STILL LOOK TO BE WEDNESDAY AND WEDNESDAY NIGHT AHEAD OF AN
APPROACHING COLD FRONT. NUDGED POPS UP TO LIKELY BY NOON WEDNESDAY
ACROSS ALL OF THE FORECAST AREA...AND CARRIED 40 TO 50 PERCENT POPS
FOR WEDNESDAY EVENING WITH SCATTERED WORDING.

FRONTAL PASSAGE NOT LIKELY TO OCCUR UNTIL THURSDAY AFTERNOON OR
EVENING WITH CHANCE POPS NEEDED THROUGH ABOUT 12Z FRIDAY. A SURFACE
RIDGE OF HIGH PRESSURE THEN BEGINS TO BUILD SE THROUGH THE WEEKEND
WHILE UPPER LEVEL HEIGHTS ALSO RISE. 12Z GFSX MOS POPS ARE TRENDING
A LITTLE DRIER THAN THE 00Z GUIDANCE...BUT FOR NOW I KEPT IN LOW
TOKEN POPS BOTH FRIDAY AND FRIDAY NIGHT FOR POSSIBLE SPOTTY DIURNAL
CONVECTION.

FOR EARLY NEXT WEEK...A WARM FRONT APPEARS TO BE A FOCUS FOR SOME
CONVECTIVE PRECIPITATION TO OUR NW BY MONDAY...WITH 12Z GFS MODEL
SHOWING A SHORTWAVE MOVING THROUGH THE UPPER RIDGE AND SPREADING
CONVECTION SE INTO THE OHIO VALLEY AND TO THE SRN APPALACHIANS BY
MONDAY NIGHT. SOME LOW LEVEL SOUTHERLY FLOW DOES RETURN BY MONDAY
WHICH SUPPORTS AT LEAST SLIGHT CHANCE POPS FOR SPOTTY DIURNAL
CONVECTION.

12Z GFSX MOS TEMPS HAVE TRENDED A FEW DEGREES COOLER ON BOTH MAX AND
MIN TEMPS FROM THURSDAY THRU MONDAY. I STAYED A BIT CLOSER TO THE
00Z GFSX MOS TEMPS AND ADJACENT NWS GRIDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN   66  90  67  83  63 /  10  20  20  70  40
KNOXVILLE AIRPORT, TN     64  88  67  83  64 /  10  20  20  60  40
OAK RIDGE, TN             64  88  65  83  62 /  10  20  20  70  40
TRI CITIES AIRPORT, TN    61  86  60  82  60 /  10  30  20  60  40

&&

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

&&

$$

MJB/TG

National Weather Service Weather Forecast Office