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

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000
FXUS64 KMRX 170715
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
315 AM EDT FRI MAY 17 2013

.SHORT TERM...-- Changed Discussion --(TODAY AND TONIGHT)...FOR EARLY THIS
MORNING..LOCALIZED DENSE FOG BEING REPORTED OVER THE NORTHERN HALF
OF THE AREA WHERE SKY COVER IS MORE SCATTERED AND BETTER CHANCE OF
RADIATIONAL FOG. HAVE INCLUDED PATCHY FOG IN THESE AREAS THIS MORNING.

AN UPPER TROUGH WILL MOVE SLOWLY ACROSS THE WESTERN HALF OF THE
TENNESSEE AND OHIO VALLEYS. ASSOCIATED UPPER DIVERGENCE AND
BOUNDARY-LAYER CONVERGENCE WILL PRODUCE BANDS OF SHOWERS AND
THUNDERSTORMS. ALSO...INCREASING LOW- LEVEL MOISTURE WILL AID WITH
DESTABLIZING THE AIR-MASS WITH DIURNAL STORMS..ESPECIALLY OVER
TERRAIN..FOR THIS AFTERNOON AND EVENING HOURS. MAIN CONCERN FOR
THESE STORMS WILL BE LOCALIZED HEAVY DOWNPOURS/URBAN AND SMALL
STREAM FLOODING AND POSSIBLY SMALL HAIL. BEST CHANCE OF STRONG
STORMS WILL BE OVER THE NORTHEAST HALF OF THE AREA WHERE MORE
SUNSHINE IS ANTICIPATED.

FOR TONIGHT...PERIODS OF SHOWERS AND ISOLATED THUNDER ANTICIPATED
WITH THE BEST CHANCE OVER THE WESTERN HALF OF THE FORECAST WHICH
WILL BE CLOSER TO THE UPPER TROUGH AXIS.

GENERALLY FOLLOWED A MIX OF MET/MAV MOS TEMPERATURES FOR TODAY AND TONIGHT.

.LONG TERM /SATURDAY THROUGH THURSDAY/...WET PATTERN IS EXPECTED TO
CONTINUE THROUGH THE WEEKEND AS THE WEAK UPPER LOW PRESSURE CENTER
TRUDGES EASTWARD WITH TIME. BY MONDAY...IT LOOKS LIKE THE UPPER LOW
WILL BE FAR ENOUGH EAST TO ALLOW SHORT WAVE RIDGING TO BUILD OVER
THE AREA. MODEL SOUNDING SHOW SUBSIDENCE INVERSION BUILDING AS WELL
IN THE 700-800 MB LAYER OVER MOST OF THE AREA BY MONDAY. THIS
PATTERN CONTINUES THROUGH TUESDAY...BUT THEN BY WED THE NEXT TROUGH
IS APPROACHING ALONG WITH ITS ASSOCIATED LIFT. WILL GO DRY IN MOST
VALLEY LOCATIONS ON MON AND TUE. FOR THE NORTHERN PLATEAU...HAVE IT
DRY MON BUT SOME POPS ON TUE AS RIDGE IS BREAKING DOWN FASTER THAT
FAR TO THE NORTHWEST. BY THE END OF THE PERIOD...THIS SYSTEM MAKE
MAKE IT OUT OF THE AREA...BUT HAVE LEFT SOME LIGHT POPS IN.

FOR TEMPS...WENT ON THE COOL SIDE OF MAX TEMPS ON SAT/SUN
CONSIDERING EXTENSIVE CLOUD COVER...BUT ALSO RELATIVELY COOL
CONVECTIVE TEMPS...ESPECIALLY ON SATURDAY. WITH LESS CLOUD COVER ON
SUNDAY NIGHT AND MONDAY NIGHT...WENT ON THE COOL SIDE OF MIN TEMPS.

THERE SHOULD BE ENOUGH INSTABILITY AROUND FOR THE THREAT OF
THUNDERSTORMS...BUT THE AMOUNT OF INSTABILITY AND/OR WIND SHEAR IN
THE ATMOSPHERE THIS FAR EAST SHOULD NOT GET OVERLY HIGH DURING THIS
PERIOD...THEREFORE...THE SEVERE STORM THREAT WILL BE LIMITED.-- End Changed Discussion --

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --CHATTANOOGA AIRPORT, TN 81 63 77 64 81 / 50 70 60 50 50
KNOXVILLE MCGHEE TYSON AIRPORT, TN 82 62 77 63 82 / 30 60 80 50 50
OAK RIDGE, TN 82 62 75 64 80 / 40 70 70 50 50
TRI CITIES AIRPORT, TN 82 57 77 59 78 / 40 50 80 50 60-- End Changed Discussion --

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

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