textproduct: Morristown

KEY MESSAGES

Updated at 149 PM EDT Sat Jul 18 2026

- Daily chances of showers and storms continue this afternoon through the weekend. A few strong to marginally severe storms could produce gusty winds and localized flooding.

- Muggy conditions with near normal temperatures continue.

DISCUSSION

Issued at 144 AM EDT Sat Jul 18 2026

A broad ridge currently encompasses much of the country over states not bordering Canada. A shortwave trough is expected to sweep southeastward over Ontario and into New England today. A fairly strong surface low will develop as it crosses northern Maine, where it may near 990 mb. The strongest dynamics will be well over there, where an enhanced risk for severe weather will be today. A marginal risk is in effect for us today and tomorrow. Damaging wind gusts are the primary threat with any severe storms, but of course, the flooding risk continues with over 1.5 inch PWATs and lowered FFGs. Increased cloud cover may tamper the threat today, where the 00z HRRR indicates sub 2k J/Kg CAPE, meanwhile, instability may exceed 2k J/Kg tomorrow. Shear for the most part won't be all that strong to support organized convection. A possible weakened line of showers and thunderstorms associated with the frontal boundary, may sweep through during the overnight hours tonight and into tomorrow morning. Timing of the line may help limit any strong to severe development.

Following the exit of the front, ridging will generally remain over the Intermountain West, while troughing resets again early to mid week, where we could see another frontal passage and one we may feel the difference from for once. Towards the end of the week, highs fall below 90 and dew points possibly below 70. Leading up until that time, temperatures will generally run around normal. The next front will be one to monitor, as SPC generally highlights The Ohio Valley to the Mid-Atlantic for possible severe chances around that time.

AVIATION

(18Z TAFS) Issued at 149 PM EDT Sat Jul 18 2026

Another round with isolated to scattered afternoon showers and storms. However, confidence in direct impacts to a terminal are lower relative to yesterday due to the presence of an upper level high centered over East TN. Tonight, a cold front will move into northern KY. A few showers and storms will be possible in the mid to late morning at TRI and maybe TYS associated with outflow. Included a mention of MVFR cigs at TRI with this activity. Additional afternoon convection tomorrow afternoon.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 74 91 74 92 / 10 70 10 30 Knoxville McGhee Tyson Airport, TN 73 88 73 89 / 40 80 30 30 Oak Ridge, TN 73 88 72 89 / 30 80 20 30 Tri Cities Airport, TN 70 85 68 87 / 50 90 20 30

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...NONE. VA...NONE.