990
FXUS64 KMRX 050105 AAA
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
905 PM EDT SUN MAY 4 2025
..NEW UPDATE
UPDATE
ISSUED AT 901 PM EDT SUN MAY 4 2025
NO CHANGES TO THE FORECAST THIS EVENING AS AN UPPER LOW CONTINUES
TO SIT OVER KY AND SOUTHERN IN, WITH VORT LOBES ROTATING AROUND IT
THAT BRING SOME SHOWERS TO OUR AREA. THIS PATTERN WILL HOLD
THROUGH TOMORROW. EXPECT TO SEE A WAVE OF SHOWERS WITH A VORT MAX
IN THE LATE OVERNIGHT AND EARLY MORNING HOURS, THEN SCATTERED
SHOWERS AND AN ISOLATED THUNDERSTORM TOMORROW AFTERNOON AS WE GET
SOME INSTABILITY UNDERNEATH THE COLD TEMPERATURES ALOFT, SIMILAR
TO WHAT WE SAW THIS PAST AFTERNOON. TEMPERATURES WILL BE
ABNORMALLY COOL TONIGHT, WITH LOWS IN THE 40S.
SHORT TERM
(THIS EVENING THROUGH MONDAY)
ISSUED AT 152 PM EDT SUN MAY 4 2025
KEY MESSAGES:
1. ISOLATED STRONG STORMS ACROSS SOUTHWEST VIRGINIA/NORTHEAST
TENNESSEE THIS AFTERNOON PRODUCING SMALL HAIL.
2. UNSEASONABLY COOL CONDITIONS TONIGHT AND AGAIN MONDAY WITH
TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL.
3. AN AREA OF SHOWERS WILL MOVE ACROSS THE AREA ALONG AND NORTH OF
INTERSTATE 40 FOR MONDAY.
DISCUSSION:
CURRENTLY, ISOLATED CONVECTION ACROSS SOUTHWEST VIRGINIA AND
NORTHEAST TENNESSEE HAVE PRODUCED SMALL HAIL UP TO PEA SIZE. MAIN
CULPRIT ARE THE LOW FREEZING LEVEL AND GOOD MID-LEVEL LAPSE RATES.
HOWEVER, THE BEST MID-LEVEL LAPSE RATES AND MLCAPE PIVOTS NORTH
INTO THE OHIO VALLEY TODAY.
FOR TONIGHT, UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST ACROSS
THE KENTUCKY WITH PLENTY OF LOW LEVEL CLOUDS OVER THE AREA. AN
UNSEASONABLY COOL NIGHT WITH TEMPERATURES DROPPING INTO THE 40S
MOST LOCATIONS. EVEN MID TO UPPER 30S OVER THE HIGHER ELEVATIONS
OF THE SMOKY MOUNTAINS.
FOR MONDAY, HREF AND DETERMINISTIC MODELS SHOW INCREASING SHOWERS
OVER THE NORTHERN HALF OF TENNESSEE INTO SOUTHWEST VIRGINIA. MAIN
FORCING IS DUE TO INCREASING QG-FORCING WRAPPING AROUND THE UPPER
LOW. THE GREATEST COVERAGE WILL BE DURING THE MORNING HOURS.
PLENTY OF SHOWERS (NORTH) AND CLOUD COVER WILL KEEP TEMPERATURES
ABOUT 10 DEGREES BELOW NORMAL. INSTABILITY IS LIMITED AT BEST SO
MAINLY SHOWERS.
LONG TERM
(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 152 PM EDT SUN MAY 4 2025
KEY MESSAGES:
1. NEAR NORMAL TO BELOW NORMAL HIGH TEMPERATURES THROUGH THE LONG
TERM.
2. UNSETTLED PATTERN WITH DAILY SHOWER AND THUNDERSTORM CHANCES
WEDNESDAY THROUGH FRIDAY, BUT A LOW CONFIDENCE FORECAST.
3. POSSIBLE DRYING TREND BY THE WEEKEND.
DISCUSSION:
WE GET A BREAK FROM THE RAIN AND CLOUDS ON TUESDAY AS HIGH PRESSURE
MAKES A BRIEF RETURN ACROSS THE AREA. HOWEVER, SOME LOW-END
PROBABILITIES FOR SHOWERS WILL REMAIN IN PLACE ACROSS EXTREME
NORTHEAST TN AND SOUTHWEST VA. THIS IS DUE TO THE VICINITY OF THE
UPPER LOW AS IT CONTINUES TO MOVE NORTHEAST AND OUT OF OUR AREA.
THEN, THE REST OF THE PERIOD BECOMES UNSETTLED. THIS IS DUE TO AN
OMEGA BLOCKING PATTERN THAT SETS UP ACROSS THE COUNTRY ALONG WITH A
CLOSED LOW TO OUR WEST ACROSS THE CENTRAL PLAINS/MISSOURI RIVER
VALLEY. THIS MEANS THAT DAILY CHANCES FOR SHOWERS AND A FEW STORMS
WILL BE IN PLACE FROM WEDNESDAY THROUGH FRIDAY. THIS IS A VERY LOW
CONFIDENCE FORECAST THOUGH DUE TO THE MESSY PATTERN THAT WILL BE IN
PLACE. IF THE CLOSED LOW STAYS FAR ENOUGH TO OUR WEST, THE ACTUAL
WEATHER MAY END UP BEING QUITE A BIT DRIER THAN THE CURRENT FORECAST
WOULD SUGGEST. SO DON'T CANCEL THOSE OUTDOOR PLANS JUST YET.
MODELS STILL TRENDING TOWARD DRYING CONDITIONS BY THE WEEKEND AS AN
AREA OF STRONG HIGH PRESSURE BUILDS IN ACROSS THE CENTRAL U.S. THIS
PLACEMENT OF THE HIGH WOULD KEEP THE REMNANT CLOSED LOW SUPPRESSED
TO OUR SOUTH, KEEPING US MOSTLY DRY.
AVIATION
(00Z TAFS)
ISSUED AT 703 PM EDT SUN MAY 4 2025
A FEW SHOWERS ARE APPROACHING CHA AND WILL MENTION A TEMPO THERE
FOR MVFR CONDITIONS WITH LIGHT RAIN. MOST OF THE NIGHT WILL BE VFR
AT ALL SITES, BUT ADDITIONAL SHOWERS ARE EXPECTED TO SPREAD INTO
THE AREA TOWARD THE EARLY MORNING HOURS. WITH THE EXPECTED CLOUD
COVER, DENSE FOG APPEARS UNLIKELY, BUT SOME GUIDANCE IS HINTING AT
HEAVY FOG AT TRI, SO CONFIDENCE IS LOW. TOMORROW, MAINLY VFR
CONDITIONS ARE EXPECTED BUT SCATTERED TO NUMEROUS SHOWERS WILL
DEVELOP IN THE AFTERNOON AND MAY AFFECT TRI.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 48 68 49 76 / 10 10 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 47 65 48 73 / 30 60 10 10
OAK RIDGE, TN 45 65 47 73 / 40 50 10 10
TRI CITIES AIRPORT, TN 46 65 46 69 / 10 70 20 20
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...DGS
AVIATION...DGS
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