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

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FXUS64 KMRX 300721
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
321 AM EDT TUE JUN 30 2015

.SHORT TERM (TODAY THROUGH THURSDAY NIGHT)...
AN ACTIVE WEATHER PATTERN WILL KEEP HIGH CHANCE TO LIKELY POPS
ACROSS THE AREA THROUGH THE SHORT TERM. ONGOING CONVECTION THIS
MORNING WILL LIKELY LEAVE NUMEROUS BOUNDARIES THAT WILL BE THE
MESOSCALE TRIGGERS FOR ADDTIONAL AFTERNOON CONVECTION. SYNOPTIC LIFT
IS ENAHNCED THIS AFTERNOON BY A JET STREAK LOCATED OVER WV AND
FALLING HEIGHTS AS THE UPPER TROUGH APPROACHES. THE NAM SHOWS GOOD
INSTABILITY AS WELL WITH MLCAPE VALUES OF 1500-2000
J/KG...SUPPORTING SOME STRONG TO SEVERE STORMS WITH WIND/HAIL
THREATS. IT IS DIFFICULT TO PINPOINT ONE PART OF THE AREA THAT IS
FAVORED FOR STORMS TODAY AND TONIGHT...SO WILL BLANKET LIKELY POPS
EVERYWHERE THIS AFTERNOON AND EVENING.

BEHIND THE UPPER TROUGH AXIS...WE WILL HAVE A NW FLOW THAT WILL
BRING UPSTREAM DISTURBANCES INTO THE AREA. THE NAM AND GFS BOTH SHOW
UPSTREAM CONVECTION AND ASSOCIATED MCV MOVING TO THE THE AREA...BUT
WITH DIFFERING TIMING AND VERY DIFFERENT QPF AMOUNTS. THE NAM IS THE
FASTER OF THE TWO AND WITH MUCH MORE QPF...AND WILL LEAN THE
FORECAST IN THIS DIRECTION. WILL HAVE LIKELY POPS STARTING WEDNESDAY
AFTERNOON THROUGH THURSDAY NIGHT AS THE 850 MB LOW TRACKS FROM
WESTERN KY TO VA. STRONG TO SEVERE STORMS WILL BE POSSIBLE THROUGH
THIS PERIOD...BUT HEAVY RAINFALL MAY BE A BIGGER CONCERN WITH
UNIDIRECTIONAL FLOW FROM 850-500 MB CAUSING TRAINING CELLS AND PW
VALUES AROUND 1.75 INCHES. WILL MENTION LOCALLY HEAVY RAINFALL FOR
NOW...AND A FLOOD WATCH MAY BE NEEDED WITH LATER FORECASTS. TOTAL
AREA-WIDE QPF THROUGH THE SHORT TERM PERIOD WILL BE 2-3
INCHES...WITH LOCALLY HIGHER AMOUNTS.

.LONG TERM (FRIDAY THROUGH MONDAY NIGHT)...
SOME UNCERTAINTY AS USUAL FOR THE LONGER TERM PERIOD OF THE
FORECAST WITH MODELS ATTEMPTING TO PREDICT CONVECTIVE EPISODES. THE
PERIOD STILL LOOKS A BIT ON THE ACTIVE SIDE...MAINLY EARLY IN THE
PERIOD...WITH THE LONG WAVE TROUGH HOLDING ITS POSITION BUT
WEAKENING TO SOME DEGREE OVER THE WEEKEND. FRIDAY MAY CONTINUE TO
BE MORE ACTIVE IN TERMS OF MORE WIDESPREAD CONVECTION WITH MODELS
INDICATING SOME SHORT WAVE LIFT IN A STILL MOIST AND UNSTABLE MID
SOUTH ATMOSPHERE. DEVELOPMENT OF SHOWERS AND THUNDERSTORMS MAY
BECOME A LITTLE MORE DIURNAL IN NATURE ON INDEPENDENCE DAY WITH A
GRADUAL DECREASE IN PROBABILITY OF PRECIP INTO MONDAY. IT IS BEST
TO ALSO GRADUALLY CRANK UP THE HEAT BACK TO WHAT IS MORE TYPICAL
FOR EARLY JULY IN THE SOUTHERN APPALACHIANS IN THIS SCENARIO OF
INCREASING INSOLATION AND DECREASING POPS.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             85  69  84  70 /  60  60  60  70
KNOXVILLE MCGHEE TYSON AIRPORT, TN  83  67  81  68 /  60  60  60  70
OAK RIDGE, TN                       83  66  80  67 /  60  60  60  70
TRI CITIES AIRPORT, TN              81  64  79  64 /  60  60  60  70

&&

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

$$
24/99



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