Sunrise 6:37 AM   Sunset 8:28 PM Moonrise 4:04 AM   Moonset 4:53 PM

  Print   HELP   Reset   Save   Recall

FXUS64 KMRX 051033 AFDMRX

Area Forecast Discussion National Weather Service Morristown TN 633 AM EDT Sun May 5 2024

New AVIATION

SHORT TERM
(Today and tonight)
Issued at 322 AM EDT Sun May 5 2024

Key Messages:

1. Warm today with isolated diurnal convection mainly across higher terrain.

2. Increasing rain chances tonight as more potent shortwave transits eastward across the Tennessee Valley and into the Southern Appalachians.

Discussion:

Subtle shortwave this morning is resulting in some isolated to scattered convection across the area. This disturbance will move east of the region this morning with drier conditions through mid-day. Increasing chances of convection across the higher elevations is expected this afternoon once again, but overall, rain chances will be limited to slight chance/chance (<50 percent) for most areas. Shortwave ridging and southerly flow will result in warm temperatures across the area.

By tonight, a stronger shortwave and associated longwave troughing will shift eastward into the Tennessee Valley. Upper level diffluence will overspread the region as we approach Monday morning with increasing chance for widespread rain showers and some embedded thunderstorms.

LONG TERM
(Monday through Sunday)
Issued at 322 AM EDT Sun May 5 2024

Key Messages:

1. Scattered to numerous showers and storms are likely through much of the week.

2. Strong to severe storms are increasingly possible Tuesday to Thursday. Localized flooding is also possible as places receive repeated, locally heavy rainfall.

3. Temperatures will remain near to above normal through Thursday with notably cooler conditions Friday into the weekend.

Monday through Wednesday

At the start of the period, a shortwave will be moving into the area from the west with broad moisture and instability in place across most of the eastern United States. This initial setup will continue showers and thunderstorms with coverage above and beyond that of Sunday. At this point, shear will still be pretty weak with thermodynamic means (MLCAPE around 1,000 J/kg) being the continued support for the storms. With PWAT values back up above the 90th percentile (near 1.5 inches), heavy downpours are likely again within any storms. Isolated flooding will remain of concern, especially in places that see repeated storms.

By Tuesday, a more organized synoptic pattern is expected with the upper jet strengthening to over 100 kts north of the Ohio River Valley. 850mb flow will also be strengthening to >30 kts with similar moisture and potentially even better instability in place.
Current model data suggests repeated rounds of convection in our area with a potential MCS arriving in the evening hours. Winds will be veered through the profile with a broad consensus of near 40 kts of deep-layer shear. While instability and timing will be more favorable to our west, strong/severe convection is certainly possible, especially in western portions of the area.

By Wednesday, the synoptic pattern will become even more favorable with another near 100 kt jet extending through the lower Mississippi River Valley, promoting additional upper divergence. Both deep-layer shear and instability are indicated to be even higher than on Tuesday. Multiple rounds of convection are indicated again with a possibly more robust MCS arriving in the evening to overnight hours.
Uncertainty still remains, but the general pattern continues to increase confidence in the potential for strong to severe storms mid- week with damaging winds as the primary concern. This timeframe continues to bear watching for flooding, in addition to the aforementioned severe threat.

Thursday through Saturday

On Thursday, a frontal boundary will move into the area from the west, which will provide continued chances for showers and storms.
Depending on how much cloud cover is lingering from overnight activity, instability may be more limited than on Tuesday and Wednesday. Also, as the upper-level pattern becomes more zonal, winds will be more uni-directional through the column. In any case, Thursday will be a time of additional rainfall on top of the several days prior. By Friday, the front will likely have moved through the area with deepening mid/upper troughing. This will usher in cooler temperatures with additional showers and/or isolated thunderstorms, depending on how far the front and antecedent moisture progresses.
On Saturday, deep troughing will keep cooler conditions with expansion of high pressure to our west leading to a reduction in rain chances.

AVIATION
(12Z TAFS)
Issued at 632 AM EDT Sun May 5 2024

Areas of fog are impacting terminals this morning, especially CHA.
Fog will dissipate by around 14z with improving conditions. A few showers and thunderstorms will be possible this afternoon, but main impacts are expected to remain along the mountains. Rain begins to arrive by 12z Monday as another system approaches the area. Winds remain generally light.

PRELIMINARY POINT TEMPS/POPS
Chattanooga Airport, TN 86 65 83 65 / 30 50 80 40 Knoxville McGhee Tyson Airport, TN 82 63 80 63 / 40 30 70 50 Oak Ridge, TN 83 62 80 63 / 40 30 70 40 Tri Cities Airport, TN 80 60 78 61 / 50 30 70 40

MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Knoxville/Tri Cities, TN,