textproduct: Morristown

KEY MESSAGES

Updated at 749 AM EDT Wed May 20 2026

- Above normal temperatures continue today with highs roughly 10 degrees above normal.

- Scattered to numerous showers and storms expected today and into the weekend. A few strong storms are possible today, and perhaps Friday as well.

DISCUSSION

Issued at 151 AM EDT Wed May 20 2026

Coverage of showers and storms will be greater today due to an increase in forcing thanks to a weak shortwave and frontal boundary moving into the area. HREF mean CAPE values are around 500 to 800 J/kg for most of the area. SPC Day 1 Outlook has a marginal risk in place for northeast TN and our southwest VA counties. This appears warranted as there will be some low-end 0-6km bulk shear across these areas; HREF means generally yield around 20 kts. For this reason, a few strong to severe storms are possible during the late afternoon/evening hours. The main threats will be small hail and isolated damaging wind gusts.

Models still showing an increase in PW values, around 1.6 to 1.8 inches, on Thursday. Widespread to numerous showers and storms are expected areawide through the day. Due to the moisture increase, some locally to moderate to heavy downpours are expected. The severe threat is lower than Wednesday though due to an absence of shear.

A warm, moist southerly flow will continue on Friday. In addition, an area of low pressure will be moving northeast from the lower Mississippi River Valley and into Missouri. This will allow for showers and storms across the region. LREF means show low/moderate instability and low-end 0-6km bulk shear across much of the area. If this occurs, a few strong to severe storms will be possible areawide.

Shower and storm chances continue over the weekend and into early next week as we remain in a southwest flow pattern. With an upper trough to our northwest, and high pressure to our southeast, several disturbances will move thorugh the southwest flow and across our region. The environment will continue to be moist and unstable and will support continued chances for showers and storms each day. The primary impacts during this timeframe lightning and locally heavy rainfall.

QPF through the next 7 days will widely vary across our area. Some areas will receive several inches of rain and other areas much less. Areas that see repeated showers and storms over numerous days will see the most rainfall.

AVIATION

(12Z TAFS) Issued at 749 AM EDT Wed May 20 2026

VFR to continue until rain or TS worsens conditions. Convection today will be scattered mostly, with mountains and Plateau focal areas, lesser confidence in the valley. Late in the period, low confidence in CIG, with at least low (10 to 20%) potential for MVFR CIGs, along with re-development of light rain showers by the end of the period. Winds generally light outside of any TS.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 89 66 84 66 / 70 50 80 80 Knoxville McGhee Tyson Airport, TN 89 66 83 65 / 50 50 90 70 Oak Ridge, TN 88 64 82 63 / 60 40 90 70 Tri Cities Airport, TN 88 63 81 62 / 30 60 80 60

MRX WATCHES/WARNINGS/ADVISORIES

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