Morristown/Knoxville, Tennessee

New DISCUSSION

• Chance of Light rain will increase late tonight across southeast Tennessee and the Plateau. Chances spread east on Sunday, but most areas remain dry.
• Dry and mild weather for the first couple of days next week.
• Increasing chances of rain and gusty mountain winds mid to late week.

Current regional radar imagery highlights an area of isolated to scattered showers approaching from the west. These showers are associated with a shortwave trough that will move across the Ohio & Tennessee valleys over the next 24 hours. The low level jet will begin to ramp up ahead of the approaching system overnight into Sunday. This will induce broad isentropic lift over middle TN and across the Plateau counties. There remains some uncertainty with how far east the precipitation will push on Sunday as residual dry air will limit rain due to evaporation. The highest confidence of any rainfall is west of interstate 75, but it wouldn`t surprise me if some sprinkles or brief showers make it east of the interstate. Gusty winds will be possible overnight into Sunday as a weak mountain wave event unfolds across the mountains and foothills. Wind speeds and gusts will remain below advisory criteria.

The first week of November will be a bit of a roller coaster. Monday and Tuesday feature a return to the mild and dry pattern we`ve observed over the past few weeks. The broad surface high pressure over the eastern CONUS and west Atlantic will build back into the region. Aloft, we`ll see upper level ridging return and hold steady through Tuesday. High temperatures will be in the mid to upper 70s and lows in the 50s. The signs of a pattern change are present upstream. An atmospheric river event is unfolding over the SW US and the associated upper trough will slowly work it`s way east into the Plains early week. Ensemble guidance features some spread with respect to the intensity, track, and timing of the mid-week system and frontal passage. However, there is strong consensus with this upper trough bringing the Tennessee valley meaningful rain at some point this week. Our upper level trough will cross the Rockies Sunday night into Monday. Our associated surface low forms over Colorado Sunday night and treks northeast to the Upper Mississippi valley by Tuesday night. From there guidance spread increases significantly, but the front will move very slowly from middle TN to eastern TN Wednesday afternoon into Thursday. This front will bring much needed rain to the area given how dry it has been this Fall. Ensemble probabilities are support a pretty strong signal for at least a quarter inch (0.25") or more of rain across the entire CWA. The best signal for higher amounts is over our western CWA at this time. Our system will also bring another potential mountain wave downslope wind event for the mountains and foothills.

For Friday into next weekend, our temperatures will cool down to more seasonable values with highs in the upper 60s and lows back in the 40s. Next weekend looks dry, but things could change given the uncertainty in timing with the mid week system.

Overall, quiet aviation conditions are expected at the 3 sites with off and on drizzle and light rain possible. The coverage will be best at CHA with reductions currently unlikely. There are also some increased winds aloft but not quite to the level of LLWS. Otherwise, surface winds will increase again during the day on Sunday with clouds generally at or above 5,000 feet AGL.

Chattanooga Airport, TN             63  54  74  57 /  60  30   0   0
Knoxville McGhee Tyson Airport, TN  67  53  75  50 /  20  30   0   0
Oak Ridge, TN                       65  51  73  50 /  30  30  10   0
Tri Cities Airport, TN              69  50  72  46 /  10  10  10   0

NC

NONE.

TN

NONE.

VA

NONE.