001
FXUS64 KMRX 022020
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
320 PM EST FRI DEC 2 2022
..NEW SHORT TERM, LONG TERM
SHORT TERM
(THIS EVENING THROUGH SATURDAY)
ISSUED AT 315 PM EST FRI DEC 2 2022
KEY MESSAGES:
1. CHANCES OF RAIN INCREASE TONIGHT THROUGH TOMORROW MORNING AS A
COLD FRONT APPROACHES AND MOVES THROUGH THE AREA.
2. STRONG SOUTHWESTERLY FLOW AT 850MB TONIGHT INTO TOMORROW MORNING
WILL PRODUCE GUSTY WINDS FOR THE HIGHER ELEVATIONS OF THE EAST TN
MOUNTAINS, SOUTHWEST VA, AND THE NORTHERN CUMBERLAND PLATEAU.
DISCUSSION:
TONIGHT AND TOMORROW
RAIN:
DEWPOINTS ARE STILL ON THE LOW SIDE THIS AFTERNOON AS REFLECTED IN
BOTH AREA OBSERVATIONS AND SOUNDINGS. THIS DRY AIR IN THE LOW TO MID
LEVELS WILL MOISTEN THROUGH TIME AS SOUTHWEST FLOW INCREASES AHEAD OF
THE COLD FRONT. THE HRRR AND RAP BOTH SHOW MEASURABLE PRECIP NOT
MOVING IN UNTIL AFTER MIDNIGHT, THOUGH A FEW SPRINKLES ARE CERTAINLY
POSSIBLE BEFORE THEN. FROM MIDNIGHT ONWARD, PRECIP CHANCES RAMP UP
FROM SLIGHT CHANCE TO CATEGORICAL POPS BY SATURDAY MORNING. WE BEGIN
TO DRY OUT SATURDAY AFTERNOON AS THE FRONT PASSES THROUGH BUT PRECIP
CHANCES WILL LINGER ACROSS THE FAR EASTERN TN MOUNTAINS THROUGH THE
REMAINDER OF THE DAY. TOTAL PRECIP WILL AVERAGE AROUND 0.25 INCHES
FOR MOST PLACES. LASTLY, SOUNDINGS STILL SHOWING VERY LITTLE
INSTABILITY SO WHILE MAINLY RAIN IS EXPECTED DON'T BE SURPRISED IF
THERE IS A RUMBLE OF THUNDER OR TWO.
WIND:
850MB FLOW INCREASES THIS EVENING AHEAD OF THE COLD FRONT AND PEAKS
AT 40 TO 50 KTS BETWEEN 06Z AND 12Z. THE CURRENT WIND ADVISORY
ACROSS THE EAST TN MOUNTAINS GOES INTO EFFECT TONIGHT AT 7 PM EST
AND EXPIRES AT 7 AM SATURDAY MORNING. HOWEVER, BASED ON LATEST MODEL
GUIDANCE, WILL EXTEND THE ADVISORY UNTIL 15Z. WIND GUSTS FROM 40 TO
50 MPH ARE EXPECTED WITHIN THE ADVISORY AREA. OTHER AREAS SUCH AS
THE MOUNTAINS OF SOUTHWEST VA AND THE NORTHERN CUMBERLAND
PLATEAU CAN EXPECT TO SEE GUSTS FROM 30 TO 40 MPH.
LONG TERM
(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 315 PM EST FRI DEC 2 2022
KEY MESSAGES:
1. DRY WEATHER TO START THE PERIOD WITH NEAR NORMAL TEMPERATURES.
2. WET PATTERN SETS UP MONDAY AND CONTINUES THROUGH THURSDAY.
POSSIBILITY OF FLOODING IF A LOCATION GETS SEVERAL DAYS OF MODERATE
TO HEAVY RAINFALL.
DISCUSSION:
BEHIND THE FRONT COOLER AND DRIER WEATHER IS EXPECTED FOR SUNDAY AND
INTO THE FIRST PART OF THE WORK WEEK, AS SURFACE HIGH PRESSURE SETS
UP ALONG WITH QUASI-ZONAL FLOW THROUGH THE MID LEVELS OF THE
ATMOSPHERE. TEMPERATURES ON SUNDAY WILL BE ABOUT 10 DEGREES COLDER
THAN SATURDAY, BUT THEY WON'T REMAIN THAT COLD FOR VERY LONG AS A
QUICK WARMUP IS EXPECTED EARLY NEXT WEEK.
ALONG WITH THE WARMER TEMPERATURES, WE MOVE INTO WHAT SHOULD BE A
MUCH WETTER PATTERN THROUGH MOST OF THE UPCOMING WORK WEEK, AS
MULTIPLE SYNOPTIC SYSTEMS LOOK TO IMPACT THE REGION. FIRST SYSTEM
LOOKS TO BE A SHORTWAVE MOVING THROUGH THE SOUTHERN STREAM ACROSS
THE TENNESSEE VALLEY AHEAD OF AN APPROACHING FRONT. MODELS ARE
COMING INTO BETTER AGREEMENT ON THE ONSET TIMING OF THIS SYSTEM,
WHICH SHOULD MOVE INTO EASTERN TENNESSEE MONDAY EVENING. THE PEAK
INTENSITY OF THIS RAIN IS EXPECTED TO BE MONDAY NIGHT INTO TUESDAY
MORNING, ALONG WITH THE STRONGEST SURGE OF GULF MOISTURE. FORECAST
SOUNDINGS CONTINUE TO SHOW OVER 1" OF PWAT IN THE ATMOSPHERE SOUTH
OF INTERSTATE 40, WITH LOWER AMOUNTS TO THE NORTH. THIS IS ABOVE THE
90TH PERCENTILE BASED ON CLIMATOLOGICAL SOUNDING DATA. SO THERE
COULD BE PERIODS OF MODERATE TO HEAVY RAINFALL OVERNIGHT, AND IF A
URBAN OR POOR DRAINAGE LOCATIONS SEE'S MULTIPLE ROUNDS OF MODERATE
TO HEAVY RAIN, THERE COULD BE SOME LOCALIZED FLOODING.
HOWEVER THERE WILL LIKELY BE A HIGHER FLOODING THREAT DURING THE
MIDDLE AND SECOND HALF OF THE WEEK, AS MORE RAIN CONTINUES TO FALL
ACROSS THE OHIO AND TENNESSEE VALLEYS. THE FRONTAL BOUNDARY BEHIND
THIS INITIAL ROUND OF RAIN IS FORECASTED TO STALL OUT SOMEWHERE
ACROSS THE OHIO OR TENNESSEE VALLEY. THE LOCATION OF THIS BOUNDARY
WILL BE THE KEY FACTOR IN DETERMINING WHAT LOCATIONS GET THE
HEAVIEST, AND REPEATED, ROUNDS OF RAIN... UNFORTUNATELY AT THIS TIME
THERE IS STILL DISAGREEMENT IN THE LONG RANGE MODELS OF WHERE THIS
BOUNDARY WILL SET UP. IF IT SETS UP ACROSS THE TENNESSEE VALLEY,
THEN OUR AREA WOULD LIKELY SEE REPEATED ROUNDS OF RAIN TUESDAY
THROUGH THE END OF THE WEEK. IF THE BOUNDARY STALLS OUT FURTHER TO
THE NORTH AND WEST (ACROSS THE OHIO VALLEY) THEN WE'D LIKELY STILL
SEE RAIN, BUT MORE DRY PERIODS IN-BETWEEN. LONG STORY SHORT, IT
LOOKS LIKE THERE WILL DEFINITELY BE MODERATE TO HEAVY RAIN MOVING
ACROSS THE OHIO OR TENNESSEE VALLEYS THROUGH MUCH OF NEXT WEEK, BUT
THERE IS STILL UNCERTAINTY ON EXACTLY WHERE THIS HEAVY RAIN WILL
OCCUR. CURRENT QPF AMOUNTS ARE SHOWING THE POSSIBILITY OF 3+ INCHES
IN SOME PARTS OF THE EASTERN TENNESSEE VALLEY FOR THE ENTIRE WORK
WEEK... HOWEVER THESE AMOUNTS CAN (AND LIKELY WILL) CHANGE AS THE
MODELS WRESTLE WITH WHERE THE FRONTAL BOUNDARY WILL STALL OUT AND
SLOWLY MEANDER AROUND. WILL CONTINUE TO HIGHLIGHT THE THREAT OF
ISOLATED FLOODING IN THE HWO. TEMPERATURES NEXT WEEK SHOULD BE BACK
ABOVE NORMAL, AND WITH THE CLOUDY SKIES, OVERNIGHT LOWS ALSO STAY
ABOVE NORMAL... WARM ENOUGH THAT ANY PRECIPITATION NEXT WEEK SHOULD
BE ALL LIQUID ACROSS THE ENTIRE REGION.
AVIATION
(18Z TAFS)
ISSUED AT 1227 PM EST FRI DEC 2 2022
VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD AS WE AWAIT
AN INCOMING WEATHER SYSTEM. CIGS LOWER TO MVFR EARLY TOMORROW
MORNING AS RAIN MOVES INTO THE AREA. LLWS EXPECTED ACROSS PORTIONS
OF THE AREA AND IS IN THE TAF AT CHA. IFR CIGS POSSIBLE LATE
TOMORROW MORNING THROUGH THE END OF THE PERIOD AT TYS AND TRI.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 50 64 37 52 / 70 80 0 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 50 62 35 50 / 70 80 0 10
OAK RIDGE, TN 49 61 33 50 / 80 80 0 10
TRI CITIES AIRPORT, TN 45 58 32 49 / 70 80 10 0
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR
BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-JOHNSON-SEVIER
SMOKY MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST GREENE-SOUTHEAST
MONROE-UNICOI.
VA...NONE.
SHORT TERM...SR
LONG TERM....ABM
AVIATION...SR
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