658
FXUS64 KMRX 131720
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
120 PM EDT SUN JUL 13 2025
..NEW SHORT TERM, LONG TERM, AVIATION
SHORT TERM
(THIS EVENING THROUGH MONDAY)
ISSUED AT 112 PM EDT SUN JUL 13 2025
KEY MESSAGE:
ANOTHER DAY OF ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON
AND EVENING. MAIN CONCERNS WITH ANY STRONG TO SEVERE STORM WILL BE
WINDS BETWEEN 40-60MPH AND ISOLATED FLOODING.
DISCUSSION:
THIS AFTERNOON & EVENING: AN UPPER-LEVEL WEATHER SYSTEM IS HANGING
OUT OVER THE GREAT LAKES, BUT IT’S NOT BRINGING MUCH SYNOPTIC
SUPPORT TO OUR REGION. WE'RE ALREADY SEEING SOME SCATTERED SHOWERS
AND STORMS EARLY THIS AFTERNOON, BUT FORECAST SOUNDINGS SUGGEST THAT
THE ENVIRONMENT IS NOT SUPPORTED OF SEVERE WEATHER. THAT SAID, SINCE
THE AIR’S PRETTY SATURATED WITH PWATS OVER 1.5" (AROUND 75% OF THE
HISTORICAL MAXIMUM FOR MID JULY) A FEW STORMS COULD DUMP A LOT OF
RAIN QUICKLY OR SEND OUT STRONG GUSTS UP TO 40 MPH.
MONDAY: THE SAME WEATHER PATTERN STICKS AROUND, WITH MORE HIT-OR-
MISS AFTERNOON STORMS. SOME OF THESE COULD PRODUCE STRONG WIND GUSTS
OR QUICK DOWNPOURS THAT COULD LEAD TO FLASH FLOODING IN SPOTS. TEMPS
WILL RISE AND HUMIDITY WILL MAKE IT FEEL EVEN HOTTER—EXPECT HEAT
INDEX VALUES NEAR 100 IN MOST OF THE SOUTHERN AND CENTRAL VALLEY.
AREAS FARTHER NORTH WILL FEEL A LITTLE COOLER BUT STILL HUMID.
LONG TERM
(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 112 PM EDT SUN JUL 13 2025
KEY MESSAGES:
1. DAILY SUMMER-TIME CONVECTION CONTINUES THROUGH THE LONG TERM.
STILL POTENTIAL FOR INCREASED COVERAGE BY LATE WEEK AS A TROUGH
RETURNS TO THE EASTERN U.S.
2. HOT CONDITIONS RETURN AS AN UPPER RIDGES STRENGTH PEAKS IN THE
MIDDLE PART OF THE WORK WEEK. HEAT INDICES IN THE MID 90S TO NEAR
100F WILL BECOME MORE COMMON ACROSS VALLEY LOCATIONS.
DISCUSSION:
TROUGH MOVES EASTWARD MONDAY WITH CONTINUED CHANCES FOR DIURNAL
CONVECTION UNDER THE HOT TEMPERATURES. FORECAST SOUNDINGS SUGGEST
THAT EFFECTIVE SHEAR REMAINS ABOUT 10 KNOTS OR LESS, WITH TYPICAL
SUMMER-TIME DIURNAL CONVECTION EXPECTED. THE STRONGEST STORMS COULD
LEAD PRODUCE WIND GUSTS UP TO 40 MPH AND ISOLATED FLASH FLOODING OF
URBAN AND LOW LYING AREAS. OUTSIDE OF STORMS EXPECT IT TO REMAIN HOT
AND MUGGY WITH WITH HEAT INDICES NEAR 100F FOR MUCH OF THE SOUTHERN
AND CENTRAL VALLEY. LOW TO MID 90S ARE MORE LIKELY FOR NORTHERN
VALLEY INTO SOUTHWEST VIRGINIA THROUGH THE FIRST HALF OF THE WEEK.
TUESDAY AND WEDNESDAY ARE CURRENTLY LOOKING TO BE THE WARMEST DAYS.
BY THURSDAY A SHORTWAVE SHOULD BE MOVING THROUGH THE NORTHERN US.
WITH WEAKENING SUBSIDENCE ALOFT, WE ARE LIKELY TO SEE INCREASED
COVERAGE OF AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY... BUT THE
TEMPERATURES WILL TREND CLOSER TO SEASONAL NORMALS. A HUMID AIR MASS
WILL KEEP INDICES IN THE 90S AND APPROACHING TRIPLE DIGITS IN
SOUTHEAST TN. UPPER RIDGE LOOKS TO BECOME DOMINANT ONCE AGAIN NEXT
WEEKEND, WITH DAILY SHOWER AND STORM CHANCES REMAINING LIKELY.
AVIATION
(18Z TAFS)
ISSUED AT 112 PM EDT SUN JUL 13 2025
ANOTHER AFTERNOON OF ISOLATED DIURNAL STORMS IS ONGOING WITH
CHANCES FOR A BRIEF LESS THAN 1 HOUR WINDOW OF STORMS IN THE
VICINITY OF AN AIRPORT. ONCE THE STORMS MOVE THROUGH EXPECT
CONDITIONS TO REBOUND QUICKLY. IF AN AIRPORT GETS HEAVY RAIN THIS
AFTERNOON IT DRAMATICALLY INCREASES THE CHANCES OF FOG IN THE
MORNING.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 95 74 96 / 10 30 10 40
KNOXVILLE MCGHEE TYSON AIRPORT, TN 72 94 73 95 / 20 40 20 50
OAK RIDGE, TN 71 93 72 94 / 20 40 10 50
TRI CITIES AIRPORT, TN 68 89 69 90 / 30 50 30 70
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...
AVIATION...
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