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

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FXUS64 KMRX 301912
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
312 PM EDT SAT MAY 30 2015

.SHORT TERM (THIS AFTERNOON THROUGH SUNDAY)...A SLIGHT DRIER AIR-
MASS ACROSS THE AREA THIS AFTERNOON WITH DEWPOINTS IN THE UPPER 50S
AND LOWER 60S. STILL EXPECT ISOLATED CONVECTION THIS EVENING WITH
BEST CHANCES ACROSS THE HIGHER ELEVATIONS AND PLATEAU. FOR
TONIGHT...AN ISOLATED STORM IS POSSIBLE...OTHERWISE PARTLY CLOUDY
SKY WITH PATCHY FOG POSSIBLE.

FOR SUNDAY...SOUTHERLY FLOW INCREASES PULLING DEEPER MOISTURE BACK
INTO THE SOUTHERN APPALACHIANS. A SURFACE TROUGH WILL APPROACH THE
AREA DURING THE AFTERNOON/EVENING HOURS. END RESULT IS A BETTER
CHANCE OF CONVECTION WITH BEST COVERAGE ACROSS THE PLATEAU DUE TO
BEING CLOSER TO SURFACE TROUGH AND HIGHER ELEVATION (OROGRAPHIC
FORCING). MARGINAL TO MODERATE INSTABILITY WITH CAPES APPROACHING
1000 J/KG WITH A WEAK WIND FIELD. MAIN CONCERNS WILL BE LOCALLY
HEAVY RAINFALL/ISOLATED FLASH FLOODING...GUSTY WINDS UP TO 45 MPH
AND FREQUENT LIGHTNING.

.LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)...MODELS STILL SHOWING
WEAK AND BROAD FRONTAL BOUNDARY DRAPED ACROSS THE REGION SUNDAY
NIGHT THROUGH MONDAY NIGHT. ALSO...WEAK UPPER LEVEL 500MB TROUGH
WILL ALSO BE IN PLACE WHICH WILL AID IN LIFT. MONDAY LOOKS TO BE THE
BEST CHANCE FOR PRECIP THROUGH THE LONG TERM WITH LIKELY POPS. BY
TUESDAY IT LOOKS LIKE THE FRONT SHOULD BE JUST EAST OF THE
APPALACHIAS BUT BECAUSE OF HOW SLOWLY THE FRONT IS MOVING IT`S HARD
TO TELL EXACTLY WHERE IT WILL BE BY THIS TIME. SO FOR SUNDAY NIGHT
THROUGH MONDAY NIGHT...EXPECT SCATTERED SHOWERS AND STORMS TO BE IN
PLACE ACROSS THE AREA. COVERAGE SHOULD DECREASE THE FURTHER WE GET
INTO SUNDAY NIGHT WITH STORMS REDEVELOPING MONDAY AFTERNOON AND
COVERAGE AGAIN DECREASING OVERNIGHT MONDAY. FOR THE FIRST FEW HOURS
OF THE SUNDAY NIGHT PERIOD AND AGAIN BY MONDAY AFTERNOON...CAPE
LOOKS SUPPORTIVE OF A FEW STRONG PULSE TYPE STORMS BUT LACKING SHEAR
WILL LIMIT THE SEVERE THREAT. PWS DURING THIS TIME WILL BE OVER THE
75TH PERCENTILE FOR THIS TIME OF YEAR BASED ON CLIMATOLOGY. THESE
HIGHER PWS COULD LEAD TO SOME BRIEF PERIODS OF HEAVY RAINFALL. WHILE
FLOODING ISN`T ANTICIPATED...STILL KEEP A WATCHFUL EYE FOR QUICK
PONDING OF WATER ACROSS LOW LYING AREAS UNDER ANY HEAVY DOWNPOURS.

AGAIN...BY TUESDAY THE FRONT SHOULD BE TO OUR EAST...BUT SPOTTY
DIURNAL CONVECTION STILL POSSIBLE. BEST CHANCE OF SHOWERS AND STORMS
LOOK TO BE ALONG THE SPINE OF THE APPLACHIANS. AFOREMENTIONED 500MB
UPPER LEVEL TROUGH IS STILL IN PLACE WEDNESDAY THROUGH FRIDAY AS IT
IS CUT OFF FROM THE MAIN FLOW AND IS SLOWLY MEANDERING EAST. OVER
THESE THREE DAYS MOISTURE IS MORE LIMITED THAN EARLIER IN THE WEEK
AS WE ARE IN POST FRONTAL AIRMASS SO ONLY SPOTTY DIURNAL CONVECTION
IS ANTICIPATED AT THIS TIME. BY SATURDAY THE TROUGH HAS FINALLY
MOVED OFFSHORE AND WEAK RIDGING IS TAKING PLACE WHICH IN TURN YIELDS
THE WARMEST DAY OF THE LONG TERM WITH TEMPS IN THE LOW TO UPPER 80S.
DIURNAL CONVECTION AGAIN POSSIBLE SATURDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             67  84  65  82 /  30  60  50  50
KNOXVILLE MCGHEE TYSON AIRPORT, TN  67  84  64  81 /  20  50  50  60
OAK RIDGE, TN                       67  85  64  81 /  20  50  50  60
TRI CITIES AIRPORT, TN              62  85  62  79 /  20  50  50  60

&&

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

$$





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