004
FXUS64 KMRX 191730
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
130 PM EDT WED AUG 19 2026
..NEW DISCUSSION, AVIATION
KEY MESSAGES
UPDATED AT 126 PM EDT WED AUG 19 2026
- REMNANTS OF UPSTREAM STORMS MAY AFFECT THE AREA LATE TONIGHT AND
THURSDAY MORNING, IF IT HOLDS TOGETHER.
- ADDITIONAL ROUNDS OF SHOWERS/STORMS POSSIBLE THURSDAY AFTERNOON
AND THURSDAY NIGHT/FRIDAY MORNING. THERE IS A MARGINAL RISK OF
SEVERE STORMS IN SOUTHERN SECTIONS THURSDAY AFTERNOON.
- MOSTLY DRY CONDITIONS WITH NEAR NORMAL TEMPERATURES THROUGH THE
WEEKEND AND EARLY NEXT WEEKK
DISCUSSION
ISSUED AT 126 PM EDT WED AUG 19 2026
CONDITIONS APPEAR LESS FAVORABLE FOR FOG TONIGHT COMPARED TO LAST
NIGHT, MAINLY DUE TO EXPECTED HIGH CLOUD COVER THAT WILL SPREAD IN
FROM UPSTREAM CONVECTION, AS WELL AS LOWER DEWPOINTS OBSERVED THIS
AFTERNOON COMPARED TO YESTERDAY.
CONVECTION THAT IS EXPECTED TO DEVELOP ACROSS THE MID-MS VALLEY THIS
EVENING WILL TRACK E-SE THROUGH TONIGHT. LATEST CAMS ARE IN GENERAL
AGREEMENT THAT THIS ACTIVITY WILL SHOW A WEAKENING TREND AS IT
CROSSES MIDDLE TN OVERNIGHT, AS INSTABILITY WILL BE LACKING.
WHATEVER REMAINS OF THE MCS WILL LIKELY REACH OUR AREA AROUND 09Z.
AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS, THIS EARLY TIMING
WILL NOT BE FAVORABLE FOR ANY SEVERE THREAT.
IN THE AFTERNOON, FORECAST SOUNDINGS SHOW PLENTY OF CAPE ABOVE A
STABLE 850-700 MB LAYER WITH LITTLE IN THE WAY OF FORCING TO
OVERCOME IT, AS THE MCV WILL BE EAST OF THE AREA BY THEN. A FEW
CAMS HAVE SOME LATE AFTERNOON CONVECTION DEVELOPING, MAINLY IN THE
SOUTHERN SECTIONS WHERE THE CAP IS WEAKER. SPC HAS ADDED THIS
AREA TO A MARINGAL RISK OF THE DAY 2 OUTLOOK. THIS SEEMS
REASONABLE IF THE CAP CAN BE OVERCOME, AS THERE ARE GOOD LAPSE
RATES ABOVE IT AS WELL AS ~30 KT OF EFFECTIVE SHEAR. BUT GIVEN THE
DISPARITY OF CAMS SOLUTIONS RIGHT NOW, CONFIDENCE IS LOW.
FORCING WILL INCREASE ON THURSDAY NIGHT AS A SHORTWAVE TROUGH
AMPLIFIES TO OUR WEST AND PUSHES A SURFACE COLD FRONT TOWARD THE
AREA. THE EXPECTED LATE NIGHT/EARLY MORNING TIMING OF THIS ACTIVITY
AND THE ELEVATED NATURE OF ANY STORMS WILL MEAN THAT THE CHANCE OF
SEVERE STORMS IS LOW. ALSO, CAMS ARE NOT IN GOOD AGREEMENT WITH
COVERAGE OF SHOWERS/STORMS THIS PERIOD, WITH SOME KEEPING ACTIVITY
WELL TO OUR SOUTH, SO FORECAST CONFIDENCE IS LOW.
DRY CONDITIONS ARE EXPECTED ON SATURDAY AND SUNDAY DUE TO BUILDING
SURFACE HIGH PRESSURE AND THE MIDLEVEL INFLUX OF DRIER AIR FROM THE
NORTH. NEXT WEEK, THERE ARE SIGNS OF ANOTHER NORTHWEST FLOW PATTERN
REMAINING ACROSS THE AREA INTO NEXT WEEK. WHILE NBM POPS ARE LOW, WE
WILL HAVE TO KEEP AN EYE OUT FOR ANY UPSTREAM IMPULSES THAT MAY
AFFECT OUR AREA NEXT WEEK. TEMPERATURES SHOULD BE NEAR NORMAL
THROUGHOUT THIS TIME FRAME.
AVIATION
(18Z TAFS)
ISSUED AT 126 PM EDT WED AUG 19 2026
DENSE FOG WAS QUITE EXTENSIVE LAST NIGHT AT TRI AND NE TN. TONIGHT,
CONDITIONS APPEAR LESS FAVORABLE FOR FOG, MAINLY DUE TO EXPECTED
HIGH CLOUD COVER THAT WILL SPREAD IN, AS WELL AS LOWER DEWPOINTS
OBSERVED THIS AFTERNOON COMPARED TO YESTERDAY. MODEL GUIDANCE IS
ALSO NOT SHOWING FOG TONIGHT, ADDING CONFIDENCE TO A VFR FORECAST.
SHOWERS MAY BE IN THE AREA OF ALL SITES TOMORROW MORNING, BUT THE
PROBABILITY OF ONE AT THE TERMINALS IS TOO LOW AT THIS TIME TO
MENTION ANY FLIGHT CATEGORY REDUCTIONS OR TS.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 94 73 92 / 20 30 50 60
KNOXVILLE MCGHEE TYSON AIRPORT, TN 71 90 70 88 / 30 50 60 60
OAK RIDGE, TN 70 89 69 88 / 40 50 60 60
TRI CITIES AIRPORT, TN 67 85 66 84 / 10 40 50 50
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...DGS
AVIATION...DGS
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