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

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FXUS64 KMRX 260735
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
335 AM EDT SAT JUL 26 2014

.SHORT TERM (TODAY THROUGH SUNDAY NIGHT)...CURRENT SURFACE ANALYSIS
SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER THE CENTRAL
APPALACHIANS...WITH A QUASI-STATIONARY FRONTAL BOUNDARY OVER CENTRAL
GA AND THE EASTERN FOOTHILLS OF THE SOUTHERN APPALACHIANS. THIS
BOUNDARY IS PROGGED TO MOVE NORTHWARD AS A WARM FRONT ACROSS THE
FORECAST AREA TODAY...BUT MODEL SOUNDINGS INDICATE A CAPPED ATMOSPHERE
OVER THE FORECAST AREA WHICH SHOULD SUPPRESS ANY POSSIBLE CONVECTIVE
DEVELOPMENT ALONG THIS FRONT. A COLD FRONT OVER THE UPPER MS RIVER
VALLEY THIS MORNING WILL MOVE SOUTHEASTWARD TODAY...AND IS EXPECTED TO
TRIGGER AN MCS OVER THE MID WEST BY THIS EVENING. THIS MCS SHOULD THEN
MOVE EAST-SOUTHEASTWARD OVER THE UPPER OHIO RIVER VALLEY TONIGHT...AND
MAY AFFECT SOUTHWEST VA AND NORTHEAST TN BEFORE AND SHORTLY AFTER
SUNRISE ON SUNDAY MORNING. AS A RESULT...SOME STRONG TO SEVERE
CONVECTION MAY BE POSSIBLE OVER THESE AREAS ON SUNDAY MORNING...WITH
THE POSSIBILITY OF DAMAGING WINDS AND LOCALLY HEAVY RAINFALL.

MODELS ARE IN GOOD AGREEMENT THAT AN UNSEASONABLY STRONG UPPER-LEVEL
TROUGH WILL AMPLIFY OVER THE EASTERN HALF OF THE NATION ON SUNDAY
BEHIND THIS COLD FRONT...WHICH WILL HELP TO CREATE A MODERATELY
UNSTABLE AIR MASS AND STRONG WIND FIELD OVER THE FORECAST AREA BY
SUNDAY AFTERNOON AND EVENING. LAPSE RATES APPEAR TO BECOME FAIRLY
STEEP THROUGHOUT THE TROPOSPHERE OVER THE FORECAST AREA BY SUNDAY
AFTERNOON AND EVENING...WITH 0-3 KM HELICITY VALUES CONDUCIVE FOR
TORNADO DEVELOPMENT (AROUND 300 M2/S2). THUS...IT APPEARS THAT THERE
WILL LIKELY BE A GOOD COVERAGE OF SEVERE CONVECTION OVER THE FORECAST
AREA SUNDAY AFTERNOON AND EVENING...WITH THE POSSIBILITY OF WIDESPREAD
DAMAGING WINDS...VERY LARGE HAIL...LOCALLY HEAVY RAINFALL...AND
ISOLATED TORNADOES. AS FOR TEMPS...GFS AND NAM GUIDANCE NUMBERS ARE
IN GOOD AGREEMENT WITH MINS FOR TONIGHT AND SUNDAY NIGHT...BUT
REVEAL SOME DISCREPANCIES WITH MAXES FOR TODAY AND SUNDAY. WILL
GENERALLY TREND TOWARDS THE COOLER NAM MAXES SINCE THIS HAS BEEN
THE TREND LATELY...AND AN EXPECTED INCREASE IN MOISTURE AND CONVECTIVE
ACTIVITY SHOULD CONTINUE THIS TREND.

.LONG TERM (MONDAY THROUGH FRIDAY)...PERSISTENT TROUGHING WILL KEEP
COOLER THAN NORMAL CONDITIONS THROUGH THE NEW WORK WEEK. SHOULDN/T
SEE MUCH IN THE WAY OF ORGANIZED OR SIGNIFICANT PRECIP AFTER THE
MONDAY MORNING FRONTAL PASSAGE...BUT SOME LOW POPS WILL BE POSSIBLE
AT TIMES. BEYOND THE VALID PERIOD...MAY ACTUALLY GET A BROAD CLOSED
LOW OVER THE OHIO VALLEY NEXT WEEKEND...WHICH MAY MAKE US A LITTLE
MORE SHOWERY. STAY TUNED.
&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             91  71  92  72 /   0   0  30  50
KNOXVILLE MCGHEE TYSON AIRPORT, TN  89  70  90  71 /   0  20  30  60
OAK RIDGE, TN                       89  70  90  71 /   0  20  30  60
TRI CITIES AIRPORT, TN              88  66  89  67 /   0  30  40  60
&&

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

$$

DMG/GC



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