618
FXUS64 KMRX 231159 AAB
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
659 AM EST TUE DEC 23 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 652 AM EST TUE DEC 23 2025
- LOW RAIN CHANCES TODAY THROUGH WEDNESDAY. MAIN MESSAGE IS THE
UNSEASONABLY WARM TEMPERATURES.
- UNSEASONABLE WARM WEATHER FOR CHRISTMAS DAY AND FRIDAY WITH HIGHS
SOME 15 TO 20 DEGREES ABOVE NORMAL. AN INCREASING CHANCE OF
MEASURABLE RAINFALL MAINLY ALONG AND NORTH OF INTERSTATE 40.
- UNSEASONABLY WARM TEMPERATURES FOR SATURDAY AHEAD OF AN APPROACHING
COLD FRONT FOR SATURDAY NIGHT/SUNDAY MORNING. GREATEST COVERAGE
OF SHOWERS EXPECTED WITH FRONTAL PASSAGE.
- MUCH COLDER AIRMASS MOVES INTO THE TENNESSEE VALLEY AND SOUTHERN
APPALACHIANS FOR LATE SUNDAY AND ESPECIALLY EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 1229 AM EST TUE DEC 23 2025
MAIN WEATHER STORY FOR MUCH OF THE WEEK WILL BE A RIDGE OF HIGH
PRESSURE BUILDING ACROSS THE SOUTHERN HALF OF THE UNITED STATES
WHICH WILL PRODUCE UNSEASONABLY WARM CONDITIONS. TEMPERATURES FOR
MUCH OF THE WEEK WILL BE 10 TO 20 DEGREES ABOVE NORMAL.
CURRENTLY, RADAR SHOWS LIGHT SHOWERS MOVING ACROSS THE REGION. THE
BOUNDARY LAYER AIRMASS REMAINS QUITE SO MUCH OF RETURNS ARE NOT
REACHING THE GROUND (VIRGA). HREF AND DETERMINISTIC MODELS SHOW
ISENTROPIC LIFT CONTINUING THROUGH THE NEXT 24-36 HOURS HELPING
TO MOISTEN THE AIRMASS AND PRODUCE LIGHT SHOWERS/SPRINKLES.
CHANCES OF MEASURABLE RAINFALL IS LOW.
CHRISTMAS DAY:
FORECAST HIGH NORMAL HIGH RECORD HIGH
CHATTANOOGA: 73 52 75
KNOXVILLE AIRPORT: 69 49 76
TRI-CITIES: 63 48 74
MODELS SHOW A SYSTEM MOVING QUICKLY IN STRONG WESTERLY FLOW ALOFT
ACROSS THE OHIO VALLEY INTO THE CENTRAL APPALACHIANS. STRONGER
ISENTROPIC LIFT AND POSSIBLE FRONTAL BOUNDARY MOVING INTO SOUTHWEST
VIRGINIA WILL INCREASE CHANCES OF RAIN SHOWERS FOR CHRISTMAS DAY AND
MUCH OF FRIDAY. RAIN CHANCES WILL BE MAINLY ALONG AND NORTH OF
INTERSTATE 40.
ENSEMBLE CLUSTER ANALYSIS AND DETERMINISTIC MODELS SHOW A MAJOR
UPPER LEVEL PATTERN CHANGE FOR LATE NEXT WEEKEND AND EARLY NEXT WEEK.
A UPPER TROUGH DIGS INTO THE EASTERN UNITED STATES WITH A STRONG
FRONTAL BOUNDARY MOVING ACROSS THE TENNESSEE VALLEY AND SOUTHERN
APPALACHIANS. THIS FRONT WILL BRING THE BEST CHANCE FOR RAIN LATE
SATURDAY NIGHT AND SUNDAY. DUE TO LIMITED GULF MOISTURE RETURN QPF
AMOUNTS WILL REMAIN LIGHT. MUCH COLDER AIR RETURNS TO THE REGION FOR
EARLY NEXT WEEK.
AVIATION
(12Z TAFS)
ISSUED AT 652 AM EST TUE DEC 23 2025
REGIONAL RADAR SHOWS SOME SCATTERED SHRA MOVING EAST ACROSS
MIDDLE AND EASTERN TN EARLY THIS MORNING. EXPECT THIS TO CONTINUE
THORUGH MIDDAY OR SO, MAINLY INVOF KTYS AND KTRI SO I HAVE SOME
VCSH MENTIONED TO ACCOUNT FOR THIS. OTHERWISE, VFR CIGS RIGHT NOW
SHOULD GRADUALLY LOWER TO MVFR TERRITORY ACROSS EAST TN BY
MIDDAY, AND POSSIBLY TO IFR LEVELS FOR THE TWO NORTHERN SITES
OVERNIGHT.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 65 54 71 55 / 10 10 10 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 62 56 67 55 / 20 30 20 20
OAK RIDGE, TN 60 53 65 55 / 20 40 10 30
TRI CITIES AIRPORT, TN 56 50 62 50 / 30 40 10 40
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...DH
AVIATION...CD
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