575
FXUS64 KMRX 110200 AAA
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
1000 PM EDT SAT MAY 10 2025
..NEW UPDATE
UPDATE
ISSUED AT 936 PM EDT SAT MAY 10 2025
AN UPPER LOW OVER THE MID-MISSISSIPPI VALLEY IS PRODUCING BROAD
SOUTHEASTERLY FLOW AND UPPER DIVERGENCE ACROSS THE TENNESSEE
VALLEY. ALSO, ISENTROPIC LIFT IS NOTED AS WELL. PERIODS OF SHOWERS
IS EXPECTED MUCH OF THE NIGHT ESPECIALLY AREAS SOUTHERN OF
INTERSTATE 40 WHERE UPPER FORCING IS BEST.
CURRENT FORECAST LOWS LOOK GOOD WITH INCREASING MOISTURE SOUTH
AND DRIER AIR NORTH PRODUCING A RANGE IN TEMPERATURES.
FORECASTS LOOK GOOD AND ONLY MINOR CHANGES PLANNED.
SHORT TERM
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 238 PM EDT SAT MAY 10 2025
KEY MESSAGES:
1. LIGHT TO MODERATE RAIN EXPECTED NEAR THE SOUTHERN TN STATE LINE
BEFORE RAIN MOVES NORTHWARD THIS EVENING.
2. SUNNIER SKIES TOMORROW WITH AFTERNOON SHOWERS AND THUNDERSTORMS.
SHORT TERM
CURRENTLY RAIN CONTINUES NEAR AND SOUTH OF THE TENNESSEE/NORTH
CAROLINA STATE LINES AS A VERY SLOW MOVING LOW SPINS IT'S WAY ACROSS
THE GULF COAST STATES FOR THE NEXT FEW DAYS. THE FORCING WITH THIS
SLOW MOVING SYSTEM IS VERY WEAK AND CLOUDY DRIZZLY WEATHER IS
EXPECTED TO BE THE PRIMARY IMPACT ACROSS SOUTHEAST TN/SOUTHWEST NC
FOR THE REMAINDER OF TODAY. AS WE HEAD INTO THE EVENING AND
OVERNIGHT HOURS THE LIGHT RAIN BAND WILL FINALLY GET A SHOVE
NORTHWARD ALONG WITH THE LOW AND SHOULD BRING PRECIPITATION CHANCES
TO MUCH OF THE SOUTHERN APPALACHIANS OVERNIGHT. ACCUMULATING RAIN
AMOUNTS ARE EXPECTED TO REMAIN VERY LIGHT WITH THE WEAK FORCING AND
LIMITED TIME DURATION OF SHOWERS OVERNIGHT.
OVERCAST SKIES TONIGHT WILL HELP KEEP TEMPERATURES WARM WITH MOST
LOCATIONS STAYING IN THE MID TO UPPER 50'S. CLOUDS WILL TRY AND
BREAK UP AND MOVE OUT TOMORROW LEADING TO INCREASED SUNSHINE FOR
MUCH OF THE DAY AND IN RESPONSE WE'LL SEE TEMPS WARM UP SEVERAL
DEGREES COMPARED TO TODAY. AFTERNOON SHOWERS AND POSSIBLY
THUNDERSTORMS WILL LIKELY DEVELOP ACROSS THE SOUTHEAST TOMORROW WITH
THE WARMER ATMOSPHERE, BUT COVERAGE IS EXPECTED TO BE MORE
SCATTERED. GREATEST COVERAGE OF STORMS IS EXPECTED TO BE SOUTH OF
INTERSTATE 40, WITH MORE ISOLATED STORMS NORTH OF THE INTERSTATE.
LONG TERM
(SUNDAY NIGHT THROUGH NEXT SATURDAY)
ISSUED AT 238 PM EDT SAT MAY 10 2025
KEY MESSAGES:
1. ACTIVE, RAINY PERIOD SUNDAY NIGHT THROUGH MIDWEEK. EMBEDDED
THUNDER SEEMS LIKELY, BUT CHANCES FOR SEVERE STORMS SEEM LOW.
2. WARMING TREND THU/FRI LOOKS SIGNIFICANT. MID AND UPPER 80S FOR
CENTRAL AND SOUTHERN VALLEY LOOK PLAUSIBLE.
3. UNCERTAINTY ON HOW LONG THE WARM/DRY WEATHER LASTS. COULD GET
BACK INTO AN ACTIVE AND RAINY PATTERN BY NEXT WEEKEND. TIME WILL
TELL.
DISCUSSION:
THE LONG TERM CONTINUES TO BE DOMINATED BY THE TRACK OF A CENTRAL
GULF COAST UPPER LOW. CURRENT GUIDANCE HAS THIS FEATURE OVER
SOUTHERN LOUISIANA AT THE START OF THE PERIOD, BUT LIFTS IT NORTH TO
THE WESTERN KENTUCKY/MISSOURI BOOTHEEL REGION BY MONDAY AFTERNOON,
THEN TO THE OHIO VALLEY BY WEDNESDAY MORNING. THIS WILL PLACE OUR
FORECAST AREA ON THE EASTERN PERIPHERY OF THE UPPER LOW, WITH GOOD
MOISTURE ADVECTION AND NUMEROUS ROUNDS OF SHOWERS EXPECTED TO ROTATE
INTO THE SOUTHERN APPALACHIAN REGION BETWEEN SUN NIGHT AND THE
MIDDLE OF NEXT WEEK. BETTER RAIN CHANCES WILL BE SEEN MON AND TUE
AFTERNOONS AS DIURNAL EFFECTS CONTRIBUTE TO WIDESPREAD CONVECTION.
HOWEVER, EVEN SLIGHT CHANCE TO CHANCE POPS SEEM WARRANTED DURING THE
OVERNIGHT HOURS SUN NIGHT THROUGH TUE NIGHT FOR MOST OF THE FORECAST
AREA. AS FOR SEVERE CHANCES, NOT LOOKING LIKE MUCH TO BE HONEST, BUT
BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE SHOW SOME BROAD 500-1,000
J/KG CAPE VALUES ACROSS THE REGION ON MON AND TUE AFTERNOONS SO
EMBEDDED THUNDERSTORMS CERTAINLY SEEMS REASONABLE IF NOT EXPECTED.
CHANCES FOR SEVERE STORMS LIKELY REMAIN OVER GEORGIA AND INTO THE
CAROLINAS WHERE BETTER INSTABILITY AND SHEAR WILL BE PRESENT.
SIMILARLY, BETTER PWAT PLUMES WILL BE SITUATED TO OUR SOUTHEAST AS
WELL SO FLOODING DOESN'T SEEM LIKE A HUGE CONCERN AT THE MOMENT
EITHER.
BY WEDNESDAY, THE UPPER LOW SHOULD BE LIFTING INTO THE OHIO VALLEY
AND ALLOW UPPER HEIGHTS TO START BUILDING FROM THE WEST BY LATE IN
THE DAY. RAIN CHANCES WILL BEGIN TO RETREAT TO THE NORTH AS WELL.
SUBSEQUENTLY, WE SHOULD SEE A WARMING TREND INITIATE DURING THIS
TIME WITH HIGHS CLIMBING INTO THE LOW 80S IN THE SOUTHERN VALLEY WED
AFTERNOON. ADDITIONAL AND MORE SIGNIFICANT WARMING TAKES PLACE THU
AND FRI HOWEVER AS RIDGING MOVES OVERHEAD. CURRENT NBM GUIDANCE
SUGGESTS HIGHS 5-10 DEGREES ABOVE NORMAL FOR THU AND FRI, WITH HIGHS
GETTING NEAR 90 DEGREES FRI AFTERNOON FOR THE CENTRAL AND SOUTHERN
TN VALLEY. WE'LL SEE IF THIS HOLDS, BUT SUFFICE IT TO SAY THU/FRI
LOOK PRETTY WARM AT THIS POINT.
FRIDAY AFTERNOON THROUGH SATURDAY SEEM UNCERTAIN WITH REGARDS TO
RAIN CHANCES. AN UPPER TROUGH/CLOSED LOW MOVES INTO THE WESTERN
CONUS EARLY IN THE WEEK, THEN EJECTS INTO THE NORTHERN PLAINS AND
UPPER MIDWEST ON THU, PUSHING A FRONT THIS DIRECTION BY FRI.
HOWEVER, THERE'S SOME UNCERTAINTY ON THE TRACK OF THIS FEATURE, HOW
MUCH IT SUPPRESSES THE RIDGING OVER THE SOUTHEAST, WHERE THE FRONT
WINDS UP BY FRI AFTERNOON, AND SO ON. WE COULD STAY DRY FRI, OR WE
COULD BE GETTING BACK INTO A MORE ACTIVE PATTERN.
AVIATION
(00Z TAFS)
ISSUED AT 733 PM EDT SAT MAY 10 2025
CHA VISIBILITY REDUCED DUE TO ONGOING RAIN. AS THE BAND OF RAIN
MOVES OUT OF THE AREA LATER THIS EVENING, MVFR CONDITIONS ARE
EXPECTED THROUGH MUCH OF THE NIGHT AS THE BOUNDARY LAYER MOISTENS.
FOR TYS AND POSSIBLY TRI, VERY LIGHT RAIN OR SPRINKLES CAN BE
EXPECTED WITH THESE BANDS AS DRY AIR IN THE BOUNDARY LAYER LIMITS
RAINFALL.
FOR SUNDAY, MARGINAL MVFR/VFR CONDITIONS WILL GIVE WAY TO VFR BY
NOON. INSTABILITY INCREASES ACROSS CHA AND TYS DURING THE
AFTERNOON WITH SCATTERED SHOWERS AND THUNDERSTORMS ARE
ANTICIPATED.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 57 75 62 75 / 70 60 90 100
KNOXVILLE MCGHEE TYSON AIRPORT, TN 56 78 61 76 / 40 60 80 90
OAK RIDGE, TN 57 79 61 74 / 30 50 80 90
TRI CITIES AIRPORT, TN 52 75 59 73 / 20 30 80 90
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...DH
LONG TERM....CD
AVIATION...DH
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