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tn discuss

Office: MEG

FXUS64 KMEG 170458

Area Forecast Discussion
National Weather Service Memphis TN
1158 PM CDT Tue Aug 16 2022

See the 06z aviation discussion.


.PREV DISCUSSION... /issued 906 PM CDT Tue Aug 16 2022/

We are currently in a break in between waves this evening. The
next wave will be moving through over the next 24 hours. Rain
should redevelop overnight and move into the Mid South overnight
and last through the morning Wednesday. Heavy rain will be the
main threat as WPC still highlights the area in a Marginal Risk of
Excessive Rainfall. The good news is that most of the rain should
be done by the afternoon, but the morning commute will be wet.
Otherwise no major changes have been made to the forecast.

PREV DISCUSSION... /issued 347 PM CDT Tue Aug 16 2022/


A relatively cool afternoon across the northern half of the Mid-
South. Temperatures range from the low to mid 70s along and north
of the Tennessee and Mississippi state line with upper 80s to
lower 90s southward. The Mid-South remains entrenched in northwest
flow aloft with heavy cloud cover along and north of I-40 at this

The majority of rainfall from this morning has moved out, as the
atmosphere has stabilized from earlier activity. Convection
remains confined to the north and south of our forecast area as
seen on latest GOES visible satellite imagery.

Another shortwave will translate through northwest flow late
tonight. This will kick off showers and thunderstorms around
midnight. This area of convection will slowly move southeast
overnight through tomorrow morning. Isolated instances of flooding
will be possible as well as typical nuisance flooding. The main
story will be cool temperatures. Highs will range from the mid 70s
to lower 80s with scattered showers and thunderstorms throughout
the day. QPF totals should remain around an inch or less.

Conditions will dry out for Thursday and Friday as high pressure
builds into the region. Expect below normal temperatures and
lower humidity through the end of the week. Humidity will be on
the increase this weekend as the stalled front lifts back north as
a warm front and dewpoints return back into the 70s.

A wet and unsettled pattern looks to setup over the region early
next week. A plume of tropical moisture will move up through the
ArkLaTex and interact with a frontal boundary over the Mid-South.
PWAT values are expected to swell above 2 inches across the entire
Mid-South. Early NBM rainfall data estimates place 3 to 5 inches
of rainfall over the region through late next week. With the rain
arriving in a slow and steady pace, some D1 and D2 drought
improvement looks likely. Nevertheless, temperatures will remain
below normal and rain chances will remain high next week.



/06z TAFs/

A band of showers, with a few embedded thunderstorms, has
developed just northeast of a JBR-MEM-TUP line. This band will
slowly sag south later tonight and throughout the day tomorrow
with the thunder potential mainly confined to the TUP terminal
after 12z. Low stratus/fog is expected to develop in the TN
Valley, possibly affecting MKL with sub 500 ft ceilings.
Elsewhere, ceilings will slowly deteriorate, mainly after 10z,
settling in the 700-1500 ft AGL range much of the day tomorrow.
We'll see some gradual improvement late afternoon and evening, but
there is a potential for fog/stratus again tonight.






Office: OHX FXUS64 KOHX 170656 AFDOHX Area Forecast Discussion National Weather Service Nashville TN 156 AM CDT Wed Aug 17 2022 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Today through Thursday) Issued at 156 AM CDT Wed Aug 17 2022 High pressure is building in from the north this morning as the moisture band that brought yesterday's light showers has slipped mostly to our south. There is enough residual moisture today to produce a few light cells south of I-40, but our rain chances are more or less at a nadir today through Thursday. There will be a little more sun today than yesterday, but still more clouds than sun, especially the farther south you go. Temperatures will remain a few degrees below normal today and again tomorrow. && .LONG TERM... (Thursday Night through next Wednesday) Issued at 156 AM CDT Wed Aug 17 2022 Look for temperatures to creep back up to seasonal normals by the weekend as rain chances start to increase owing to a shortwave passage Friday night and Saturday. A much stronger surface system will begin impacting Middle Tennessee Sunday night and Monday and this will also be accompanied by a deep upper trough. Cooler temperatures and even higher rain chances will stay with us until at least the middle of next week. QPF values from Sunday night through Tuesday look to be particularly robust, and cumulative QPF values for the next 7 days range from less than 2" across portions of the Cumberland Plateau to around 3" along the Tennessee River. Still, the risk of hazardous weather through the forecast period remains low. && .AVIATION... (06Z TAFS) Issued at 1210 AM CDT Wed Aug 17 2022 The forecast will really be a wind and cloud forecast for the TAF Period. VFR expected at BNA...MVFR with BR for CKV and MQY...and IFR/LIFR with BR and LIFR CIGs for CSV. Winds will be light and variable/calm overnight and from the north 10 kts or less during the day. && .PRELIMINARY POINT TEMPS/POPS... Nashville 85 65 86 68 / 10 0 0 10 Clarksville 83 63 85 64 / 0 0 0 0 Crossville 79 61 80 63 / 10 0 0 20 Columbia 83 64 86 66 / 20 10 0 10 Cookeville 81 63 82 66 / 0 0 0 10 Jamestown 78 61 80 63 / 10 0 0 10 Lawrenceburg 82 63 85 66 / 20 10 0 10 Murfreesboro 85 64 86 67 / 10 0 0 10 Waverly 83 63 85 65 / 10 0 0 0 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Rose LONG TERM....Rose AVIATION.....12
Office: MRX FXUS64 KMRX 170717 AFDMRX AREA FORECAST DISCUSSION National Weather Service Morristown TN 317 AM EDT Wed Aug 17 2022 .SHORT TERM...(Today and tonight)... Key Messages: 1. Scattered showers in the mountains and the northeast again today. Likely dry elsewhere. Discussion: No changes in the overall pattern from 24 hours ago so we'll likely see a near repeat of yesterday's weather. Upper low remains centered over the New England area, with WNW flow aloft locally. A shortwave within the upper low will swing southeast across the Ohio river valley this afternoon, with a +70kt jet streak ahead of it, located over the northern half of the forecast area. Gut reaction to the placement of this jet would be to think that there would be a notable increase in shower activity versus the last couple of days, but a significant drying trend is noted in forecast PWATs and model soundings predictably show very little in the way of instability over the northern areas and next to nothing in the south. Even the typically more bullish NAM has only a few hundred Joules of MUCAPE this afternoon in the north and the SPC HREF probabilities of greater than or equal to 500 J/kg of CAPE barely exceeds 40 percent. As such, believe that like the last couple of days, shower activity will largely be tied to the terrain where low level upslope flow can help push parcels to their LFCs. Doubt there will be much lightning activity, but did keep a slight chance of thunder in the forecast as NBM probability of thunder support at least a mention of it. Otherwise, not a lot to talk about in the short term. Temperatures will remain below normal today, generally in the low to mid 80s this afternoon and tonight will be in the 60s. Some patchy fog and low clouds will be present across the northern half of the CWA through mid morning and expect similar conditions again tonight. CD .LONG TERM...(Thursday through Tuesday)... Key Messages: 1. Unsettled pattern throughout much of the forecast period. Greatest coverage of showers and thunderstorms will be Friday onward, peaking on Monday. 2. Daily high temps will run below normal with lows near normal. Discussion: Deep layer troughing will dominate the pattern through the extended period bringing continued unsettled weather and near to slightly below normal temperatures. Beginning on Thursday, troughing will encompass much of the eastern two-thirds of the country with two upper low centers established north of the Great Lakes. The western most feature will dive southward into the base of the longwave trough Thursday into Friday. Weak northerly flow continues Thursday limiting moisture return. Will keep PoPs lower Thursday and Thursday night given weak upper forcing and low PW's. On Friday, a shortwave is forecast to move across the Tennessee Valley increasing SW flow across the area. Low level flow veers toward the south advecting boundary layer moisture poleward. The combination of isentropic ascent in concert with slightly better forcing aloft will contribute to more scattered showers and thunderstorms Friday and Friday afternoon. SW flow aloft continues into the weekend along with lower heights as mean troughing continues across the region. Overall forcing should be fairly weak though, as a more pronounced upper low remains to the northwest. Better moisture along with lower heights will contribute to daily convection this weekend, with the best coverage expected across the terrain. Heading into early next week, the upper low mentioned previously meanders across the Great Lakes resulting in continued southwest upper level flow. The area will be on the southern fringes of stronger mid level flow providing better ascent for more coverage of showers and thunderstorms. Will follow close to NBM PoPs Monday and Tuesday. Stronger southwest flow will contribute to more cloud cover both days, resulting in slightly cooler high temperatures. Diegan && .AVIATION... 06Z TAF DISCUSSION. Some scattered showers are once again expected over the mountains today. Doubt there will be any that affect terminals, but KTRI would stand the best chance so VCSH should be sufficient. Plenty of low level moisture in place this morning should produce some LIFR conditions again at KTRI through daybreak. Otherwise, expect a return to VFR categories at all terminals after 14z. CD && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 84 67 86 69 82 / 10 20 30 30 60 Knoxville McGhee Tyson Airport, TN 83 64 85 66 82 / 10 10 30 20 70 Oak Ridge, TN 82 64 84 66 82 / 10 10 20 20 70 Tri Cities Airport, TN 80 60 82 62 80 / 30 10 30 10 70 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$