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
855 FXUS61 KRNK 100943 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 543 AM EDT Wed Jul 10 2024 .SYNOPSIS... Low pressure tracks from the Ohio Valley into Ontario today and pushes and cold front through the region along with thunderstorms this afternoon and evening. The front becomes stationary along the Mid Atlantic and Carolina coast with ripples of low pressure tracking along the boundary Friday through Sunday. This will result in typical summer temperatures and daily chance of precipitation. && .NEAR TERM /THROUGH TONIGHT/... As of 345 AM EDT Monday... Key messages: - No change to Heat Advisory - Highest confidence of thunderstorms late this afternoon Axis of synoptic scale trough remains over the Ohio valley today and tonight. As the surface low tracks into Ontario, the cold front moves east, eventually becoming stationary to the upper flow. Models have the wind shift at the surface and 850 MB, the surface pressure rises and the sharp gradient of more stable air crossing through the region this afternoon and evening. The best lift and opportunity for thunderstorms along and ahead of the front will be from 18Z/2PM through 03Z/11PM. Pre-storm environment will have modest 0-1km and 0-3KM shear and decent CAPES. SPC HREF even has an axis of non-zero, but still low, STP extending into northeast Virginia. Agree that the primary threat will be damaging wind. As a line of storms organizes east of US-29 late this afternoon, the probability increases. Plus water-loading will likely bring down some trees. Torrential rainfall rates are expected due to abundant moisture, as precipitable water values will be in the 1.9 to 2.3 inch range. Surface dew points will remain in the mid 60s to mid 70s ahead of the front with southwest wind gusting 15 to 25 mph once mixing begins. The heat index by this afternoon will again be around 105 in the Virginia and North Carolina piedmont. No changes to the Heat Advisory are planned at this time. Behind the front tonight, dew points drop into the mid 50s to mid 60 and the wind turns to the west and northwest. This upslope flow will bank some low clouds along the west slopes of the central Appalachians late tonight. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... ... As of 440 AM EDT Wednesday... Key Messages: 1: Less rain Thursday 2: Continued above normal temperatures A frontal boundary is progged to stall out in the eastern part of VA by Thursday. This will make for a slightly drier environment on Thursday and Friday, but temperatures will remain above normal through the period. What this will accomplish is a slight reprieve in shower/storm formation to end the week. Most precipitation that forms will likely occur towards central VA and the Piedmont, closer to the area where the stalled front will be sitting. By Friday dewpoints will be creeping back into the upper 60s and 70s, so expect diurnal convection to be a bit more widespread than on Thursday. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 100 PM EDT Tuesday... Key Messages: 1) Confidence is increasing for the heat and humidity to rise again by early next week. 2) Chances of showers and thunderstorms could continue each afternoon during this forecast period. Although weak high pressure should spread across the Mid Atlantic on Saturday, the air mass will not become appreciably cooler or drier. Consequently, lingering moisture and orographical lift could spark isolated showers and thunderstorms during Saturday afternoon. This diurnal trend of scattered afternoon convection could continue for the foreseeable future as the heat and humidity starts to climb again as the flow turns toward the southwest early next week. Highs will remain well above normal, and continued moisture advection will lead to heat indices approaching 3 digits. It just doesn`t look like this heat is going anywhere, anytime soon. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... As of 400 AM EDT Monday... Axis of synoptic scale trough remains over the Ohio valley today and tonight. As the surface low tracks into Ontario, the cold front moves east, eventually becoming stationary to the upper flow. Models have the wind shift at the surface and 850 MB, the surface pressure rises and the sharp gradient of more stable air crossing through the region this afternoon and evening. The best chance of storms between 21Z/5PM and 01Z/9AM. Will leave any mention out of KLWB and KBLF as a line of storms organizes east of US-29 late this afternoon, the probability increases. The ceiling and visibility with any of the storms will be MVFR. Southwest wind gusting 15 to 25 mph once mixing begins. The heat index by this afternoon will again be around 105 in the Virginia and North Carolina piedmont. No changes to the Heat Advisory are planned at this time. Behind the front tonight, dew points drop into the mid 50s to mid 60 and the wind turns to the west and northwest. This upslope flow will bank some MVFR to IFR clouds along the west slopes of the central Appalachians late tonight. WIll have these lower ceilings in at KLWB and KBLF after 06Z. Forecast confidence is average. AVIATION OUTLOOK... Expect the pattern to stay humid with daily chance of storms mainly afternoon/evening through the week. IFR to MVFR fog at night possible. Mainly VFR outside storms and fog/low stratus mornings. Sunday is the most likely to have no flight restrictions due to showers and thunderstorms. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Heat Advisory from noon today to 8 PM EDT this evening for VAZ033-034-043>047-058-059. NC...Heat Advisory from noon today to 8 PM EDT this evening for NCZ005-006. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...VFJ LONG TERM...PW/VFJ AVIATION...AS