Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
625 FXUS61 KRNK 140701 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 301 AM EDT Tue May 14 2024 .SYNOPSIS... A low pressure system will cross the Mid Atlantic through Wednesday to bring showers and scattered thunderstorms. Weak high pressure should provide drier air for Thursday, but another low pressure system will bring more rain for the end of this week. && .NEAR TERM /THROUGH TONIGHT/... As of 214 AM EDT Tuesday... Key Messages: 1) Showery period through tonight, some locally heavy rain possible. 2) Dense fog possible along higher ridges this morning. Models trying to zero in on patches of rain moving across the area early this morning helping to saturate the lower levels. Light rain has made it as far north as I-64 corridor. A lull in activity expected with another shot of isentropic lift pushing across the area by dawn, but models are varied on location. Seems along/east of the Blue Ridge has a better area of upper divergence so will have higher pops here. Low pressure enters central NC this afternoon, and some instability gets into the mountains of WV and into central NC but appears airmass will be fairly stable over us, so limiting thunder to mainly the WV mountains possibly reaching our NC mountains and foothills this evening. Any storm could drop some heavy rain, but overall flooding risk is marginal with best chance along/east of the Blue Ridge closer to the surface low. Severe storms are not likely given stable airmass, though the latest outlook pushes marginal into the NC mountains. Thinking is stronger instability stays along/south of I-40 in NC. Warm front lifts north into our area tonight with low pressure tracking into the VA piedmont by dawn Wednesday. Expect better chance of showers (70-100%) tonight. With light rain and clouds lowering this morning, we have some dense fog along the higher ridges from Floyd to Boone/Blowing Rock. This will likely be the case through the morning but mainly elevations above 3000 ft. Fog may also become dense at the higher ridges further north along the Blue Ridge into the Alleghanys toward dawn as well. Special Weather Statements will cover this localized areas, as not enough coverage for a dense fog advisory. Plenty of clouds and rain today will keep highs in the 60s. Temps fall little tonight with warm front lifting north with more showers with upper 50s to lower 60s expected. Forecast confidence is high that most areas will have measurable rain, but lower on amounts and thunderstorm chances, and timing today as models vary on each upper disturbance driving the rain chances. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... As of 230 AM EDT Tuesday... Key Messages: 1. Showers and possible storms on Wednesday. 2. Drier weather Thursday. 3. Shower and storm chances increase again Friday. By Wednesday morning, a low pressure system will be over most of the Mid Atlantic region, with a warm front extending west to east across VA and NC, and a cold front along the southeastern coast. Some showers may be lingering over the western slopes by the start of this forecast period, as moisture wraps around the low back into the area. Coverage of showers will increase through the day Wednesday, and some thunderstorms are possible by Wednesday afternoon as instability increases with daytime heating and the passage of the upper shortwave. Deep layer shear is forecast to be between 30 and 40 knots over the Carolinas, which would be supportive of multicell thunderstorms, and if coinciding with the peak heating, and thus greatest instability, storms could become severe. Above normal precipitable water values are forecast, so localized heavy rainfall is possible. Showers and storms decrease Wednesday night as the surface low moves offshore, and mid level ridging will build overhead by Thursday, bringing a brief reprieve from the rain. The next low pressure system approaches the Ohio Valley by Friday, and showers could begin for the western counties in the forecast area as early as Friday afternoon, although notable differences in timing are still present in the long range deterministic models. The 500mb shortwave crosses the area by late Friday, increasing chances for thunderstorms Friday afternoon. With the discrepancies in the models, there is still plenty of uncertainty in the arrival and location of the heaviest rainfall for the end of the week. Temperatures will trend warmer through this forecast period, although plenty of cloud cover will keep highs in the 60s and 70s for Wednesday, but warming a few degrees for Thursday and Friday. Lows will be mild, generally in the 50s and low 60s each night. && .LONG TERM /SATURDAY THROUGH MONDAY/... As of 230 AM EDT Tuesday... Key Messages: 1. Unsettled weather to start the weekend, drier weather to start the work week. 2. Near normal temperatures Saturday, warming to a few degrees above normal by Monday. Another upper trough and low pressure system approaches the Ohio Valley by the end of the work week, reaching the Mid Atlantic and central Appalachians by the start of the weekend. As mentioned in the short term forecast discussion, there are still discrepancies in the timing of this system and the placement of its associated fronts, so showers may be ongoing at the start of the long term forecast period, and increase in coverage by Saturday afternoon and evening. Storms are possible Saturday afternoon as instability increases with daytime heating. Most of the deterministic models show the low departing offshore by Sunday, and mid level ridging returning to the area by Monday, so at this time, thinking drier weather for the end of the weekend and beginning of the work week. Temperatures will be near normal for Saturday, warming to a few degrees above normal by Monday. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... As of 118 AM EDT Tuesday... Low pressure will approach from the southwest this morning, which will increase and lower clouds. Ceilings should lower to MVFR and fall further to IFR by early this morning with periods of rain/fog possible. Poor ceilings and at times vsbys are likely through the rest of the taf period with off and on showers expected. Heavier rainfall rates are possible for LYH and DAN as the warm front from this low pressure system lifts northeastward. Chances of thunderstorms will gradually increase by Tuesday afternoon but appears too isolated to have in tafs. Best chance would be around BLF. Extended Aviation Outlook... Poor flying conditions will continue through into Wednesday as a cold front approaches from the west. Scattered showers and thunderstorms should continue through Wednesday evening but start to fade by Wednesday night as the cold front exits. VFR conditions should return for most terminals by Thursday due to weak high pressure passing to the north. However, another low pressure system could arrive during Friday afternoon into Saturday to bring low ceilings and scattered showers and thunderstorms. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PW/WP NEAR TERM...WP SHORT TERM...AS LONG TERM...AS AVIATION...PW/RCS/WP