889
FXUS64 KMRX 181200
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
800 AM EDT TUE AUG 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 741 AM EDT TUE AUG 18 2026
- REGULAR WARM TO HOT AUGUST TEMPERATURES TO CONTINUE, WITH ON AND
OFF RAIN AND THUNDERSTORM CHANCES RETURNING THURSDAY AND
CONTINUING INTO THE WEEKEND.
DISCUSSION
ISSUED AT 144 AM EDT TUE AUG 18 2026
WE WILL SEE SOME MINOR RELIEF NEXT TWO DAYS, WITH A RETURN TO
TYPICAL SUMMERTIME TEMPERATURES AND A DROP IN THE OVERALL PWAT FOR
THE ATMOSPHERE. PWATS DROP DOWN TO 1.2" OR SO, WHICH IS JUST ABOVE
THE 25TH PERCENTILE FOR AUGUST, A TIME OF YEAR IN WHICH WE'RE AT THE
CLIMATOLOGICAL MAXIMUM FOR VERTICAL WATER CONTENT. SINCE THE UPPER
HEIGHTS ARE OTHERWISE FAIRLY FLAT, WE ONLY RETURN TO NEAR OR
SLIGHTLY ABOVE TYPICAL HIGHS FOR AUGUST, SO NOT SURE HOW MUCH
JUMPING FOR JOY OUR ANTI-HUMIDITY CABAL WILL BE DOING THIS WEEK. WE
WILL ALSO LIKELY REMAIN DRY THE NEXT TWO DAYS, WITH SURFACE RIDGING
OVERHEAD AND NO OBVIOUS DISCERNIBLE SOURCE OF FORCING TO GET US
STORM DEVELOPMENT.
UNFORTUNATELY WE GET ANOTHER SHORTWAVE TO ARRIVE ON THURSDAY, WHICH
HAS THE SIDE EFFECT OF RE-INTRODUCING MORE RAIN AND STORM CHANCES TO
OUR REGION, WITH HIGHER CHANCES IN THE NORTH. 30 TO 40 KNOTS OF
SHEAR EXIST THURSDAY INTO THURSDAY NIGHT, GFS AND LONG RANGE RRFS
BOTH DEPICT A DYING STORM CLUSTER EARLY ON THURSDAY TO OUR WEST,
THEN A LULL LIKELY FROM CLOUD DEBRIS, THEN POTENTIAL FOR SCATTERED
PM AND LATE NIGHT THUNDERSTORMS. WHETHER OR NOT THAT SCENARIO COMES
TO FRUITION IS AN UNKNOWN. CAPE IS A BIT OF A QUESTION, THOUGH
DEPENDING ON HOW THE MORNING GOES WE MAY REALIZE MORE CAPE THAN THE
LOW-BIASED GFS DEPICTS. SHEAR PROFILES ARE MORE FAVORABLE FOR STRONG
WINDS. SOMETHING TO WATCH, ANYWAYS. SCATTERED RAIN AND STORMS THEN
WILL LIKELY REMAIN IN THE FORECAST INTO THE WEEKEND, AS A SERIES OF
SHORTWAVES OCCUR BEFORE A LARGE TROUGH DIGS INTO THE GREAT LAKES AND
THEN THE NORTHEASTERN US SUNDAY INTO MONDAY.
AVIATION
(12Z TAFS)
ISSUED AT 741 AM EDT TUE AUG 18 2026
LOW CIG AND BR IMPACTING THE TERMINALS THIS MORNING. MODELS DEPICT
CIG LIFTING WITH TIME THIS MORNING. ONCE WE IMPROVE TO VFR, DRY
WEATHER IS ON TAP TODAY UNDER STRENGTHENING HIGH PRESSURE.
ISOLATED ACTIVITY COULD MAINLY IMPACT NEAREST TRI, BUT CONFIDENCE
TOO LOW TO INCLUDE IN TAF. CLEARING AND CALM OVERNIGHT TONIGHT
WITH POSSIBLE CIG AND VSBY TO WATCH FOR AGAIN, BUT MOST LIKELY NOT
AS BAD AS THIS MORNING.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 93 69 96 72 / 0 0 0 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 89 68 91 69 / 10 0 0 20
OAK RIDGE, TN 89 66 91 70 / 10 0 0 20
TRI CITIES AIRPORT, TN 86 64 88 66 / 20 0 0 10
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...WELLINGTON
AVIATION...KS
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