958 FXUS61 KRNK 241847 AFDRNKArea Forecast Discussion National Weather Service Blacksburg VA 247 PM EDT Wed Sep 24 2025
.SYNOPSIS... Broad area of low pressure over the central United States will move slowly east with time, resulting in a daily chance for showers and thunderstorms through the end of the week.
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.NEAR TERM /THROUGH THURSDAY/... As of 215 PM EDT Wednesday...
As per previous thoughts, the edge of the morning cloud shield along and north of the I-81 corridor has focused convective initiation due to increased baroclinity from the differential heating/solar sheltering. CAMs were in good consensus with a somewhat linear cluster of development triggering generally along the foothills and then propagating eastward into the Piedmont where there has been greater destabilization. With high PWATs in place and possible training of such cells this afternoon, will need to focus on isolated heavy rainfall and hydrometeor loading aiding downdrafts to generate gusty winds.
Thursday looks to provide additional rounds of shower activity and afternoon storm potential under the persistent SW flow aloft along the eastern upper trough. Guidance is indicating a bit stronger bulk shear close to 40 kts in the 0-6 km layer along with a potential to get close to 2000 J/kg of SBCAPE. The question will be if such instability can be attained given possible lingering cloud coverage. SPC does have the eastern majority of the CWA in a Day 2 Marginal Risk for severe storms with damaging wind as the main threat.
Min temps should be well above normal in the 60s for most areas tonight given the ample moisture and cloud cover, then generally increase to the 70s for the mountains and low to mid 80s for the Piedmont Thursday afternoon.
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.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 150 PM EDT Wednesday...
Key Messages:
1) A cold front will move through the area Thursday night into Friday.
2) Shower/storm chances continue through the weekend.
3) Temperatures fall behind the front to near to just below average on Saturday.
A cold front will be moving into the area Thursday night, with showers and storms expected to linger into the night as the front pushes through. Some isolated severe weather will still be possible early on before diurnal heating fades, especially for the eastern Piedmont in the form of damaging wind gusts. As the front pushes through by Friday morning, it stalls just to our east. An upper- level trough will continue to drive moisture northward into the area, and with the frontal boundary still around, will continue to keep showers/storms in the forecast for both Friday and Saturday. Rain chances have increased since yesterday, with scattered chances on Friday, mostly south of US-460, with deeper moisture expected for Saturday with widespread showers/storms throughout the day and through the end of the period, again with higher coverage to the south in NC. The upper trough will begin to close off and become a cutoff low that will sit over the Deep South through the weekend as the main jet stream to the north lifts back into Canada. The southeasterly flow aloft around the cutoff low will help to keep widespread cloud cover over the entire forecast area.
Rain totals have also increased for the period, with around an inch expected for the mountains. Locations along/east of the Blue Ridge will see higher moisture, and in turn, higher rainfall totals closer to the stalled front. Around 1-2" can be expected, with locally higher amounts likely in the heaviest convection. A marginal risk for excessive rainfall is across the NC mountains each day, and for east of the Blue Ridge on Saturday.
Temperatures will be near to slightly above normal, with 70s for the mountains and low to mid 80s for the Piedmont as the front clears through. On Saturday, temperatures drop due to heavy cloud cover, with highs in the 60s/70s. The increased cloud cover will also keep overnight lows mild, in the 60s until 50s return for the mountains Sunday morning.
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.LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 150 PM EDT Wednesday...
Key Messages:
1) Rain chances continue each day through the period.
2) Near normal temperatures through midweek.
3) Uncertainty with potential tropical systems and their impacts.
Beginning Sunday, the upper low that remains cutoff over the Deep South will continue to drive moisture up into our area, but drier air will also begin to wrap around the low. This will help to limit the coverage of afternoon showers/storms, but rain remains in the forecast each day through the period, though PoPs lower from around 50% down to 30% by midweek. The stalled surface frontal boundary drifts east and stays along the coast.
There is great uncertainty in the forecast for early next week, as it is looking increasingly likely that not one, but two tropical systems will form in the Western Atlantic over the weekend. These systems will be side-by-side and heading northeast towards the US initially. The eastern system will not impact the CONUS, as it is expected to turn north and then out to sea. There is less confidence in the western system and where it will go due to a complex synoptic setup. The cutoff upper low over the Southeastern US could grab the system and pull it towards the Eastern US. If this occurs, then tropical impacts for our area would become more likely. However, models currently are leaning towards the eastern tropical system becoming stronger, which will draw in the weaker western system and pull it away from land with little to no direct impacts for our area. This could change as more data is gathered about steering currents and the potential systems as they develop. Regardless of the track, tropical moisture from the Atlantic will be advected into the area early next week, enhanced by flow around the upper low over the US. While currently PoPs are kept low, this could change once details become known.
Temperatures remain on the cool side, though stay near normal. Highs each day will be in the 70s through midweek, when 60s return west of the Blue Ridge. Lows will be in the 50s/60s.
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.AVIATION /19Z WEDNESDAY THROUGH MONDAY/... As of 230 PM EDT Wednesday...
Scattered TSRA possible this afternoon for most of sites except LWB and BLF where it may just stay rain showers or light rain. Should be on and off precip through the forecast period. Most sites this afternoon should have cigs in the MVFR to low end VFR range and then lowering again tonight to MVFR/IFR (possibly LIFR). Patchy fog is also possible especially for locations that receive rainfall this evening. Could have some stronger TSRA Thursday afternoon that reduce VSBYs and have VRB gusts. Winds otherwise should be south to SW at 10 kts or less.
EXTENDED AVIATION OUTLOOK...
Chances of showers and thunderstorms will persist through the remainder of this work week as a broad upper level trough of low pressure and associated surface cold front slowly tracks eastward and across the Appalachian Mountains. MVFR ceilings and visibilities are possible in the heavier storms, and some patchy fog may occur during the overnight hours in response to the increasing moisture. Thursday appears to have the greatest coverage of showers and thunderstorms. By Saturday, the cold front should reach the East Coast but high uncertainty as to whether drier air brings more widespread VFR conditions. Some models are now trending wetter with low pressure stalling over the area and bringing unsettled weather for the weekend in addition to tropical concerns increasing near the coast.
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.RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None.
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SYNOPSIS...PM NEAR TERM...AB SHORT TERM...JCB LONG TERM...JCB AVIATION...AB/PM
NWS RNK Office Area Forecast Discussion