Blacksburg forecast discussion

What Has Changed

Aviation discussion updated.

Rain chances were increased across the mountains during this evening, though rainfall amounts are similar to the previous forecast.

Key Messages

and a few thunderstorms, along with breezy winds through Saturday morning.

2) Confidence is high for frost and pockets of freezing temperatures to occur across the mountains on Sunday morning.

Discussion

KEY MESSAGE 1: A cold front arriving today will trigger scattered showers and a few thunderstorms, along with breezy winds through Saturday morning.

Starting the morning off with low clouds across the Piedmont, and areas of locally dense fog across portions of the New River Valley where skies are mostly clear. These conditions will improve quickly after 10 AM as wind speeds gradually increase ahead of an approaching cold front.

Today will provide the last of the summer-like temperatures for a while as warm air pools ahead of the approaching front. With highs reaching into the mid/upper 70s across the mountains, and into the 80s further east, will be testing the record high temperature of 85 for Roanoke if clouds can break up early enough. Afternoon highs will reach within a few degrees of records for several other locations as well.

The cold front will enter southeast West Virginia from the northwest during late afternoon/early evening, triggering a broken line of showers and possibly a thunderstorm or two along its leading edge. The front will pass east quickly, reaching the Highway 29 corridor between Lynchburg and Danville by around 8 PM and exiting our area to the east by 10 PM. Forecasting mainly shower activity this evening across the mountains due to limited energy, but cannot rule out a few storms developing across the Piedmont given the unusually warm temperatures there. Any potential for damaging wind gusts appears to be highly limited. Showers will persist across our area through much of the night as a supporting upper level disturbance passes across the central Appalachians, with lingering rain forecast to tapper off around sunrise Saturday.

Given the strength of this cold front, wind gusts will increase to between 15 mph and locally 25 mph from the west-southwest during mid-morning and through mid-afternoon, and will then increase into the 20 mph to locally 35 mph range from the northwest in the wake of the front's passage. Winds will remain breezy overnight, and through much of Saturday before gradually diminishing after sunset Saturday evening.

KEY MESSAGE 2: Confidence is high for frost and pockets of freezing temperatures to occur across the mountains on Sunday morning.

With wind speeds decreasing and skies clearing Saturday night, confidence is high for areas of frost to develop across the mountains and possibly even the foothills east of the Blue Ridge. There are also signals that some of the more sheltered mountain valleys will fall below freezing by sunrise Sunday, effectively ending the growing season there. Confidence is not high that the coverage of sub-freezing temperatures will extend beyond those locations however, given the possibility that winds may remain just breezy enough to mix the slightly warmer air aloft down to ground-level. Still, day shift may opt to issue a Freeze Watch for some mountain locations later today if newer data supports it.

After another chilly night on Monday night, temperatures will moderate to near normal for mid-October through the remainder of the next workweek. No hazardous weather is expected during this period.

Aviation /06Z Friday Through Tuesday/

Starting the day with widespread IFR ceilings for locations east of the Blue Ridge, and with pockets of fog in place in the river valleys of southwest Virginia and southeast West Virginia. Given the approach of a cold front today, winds speeds will increase after 14Z, allowing low clouds and reduced visibilities to improve quickly to VFR conditions by 16Z. Gusts will range from 15kt to 20kt from the west-southwest from late morning through mid-afternoon.

A cold front will pass across KBLF and KLWB in southeast West Virginia during the 20Z to 22Z timeframe, triggering a broken line of showers and possibly a thunderstorm or two, in addition to a northwesterly wind shift. The front will push quickly east, reaching KDAN and KLYH during the 17/00Z to 17/02Z timeframe, triggering showers and possibly of a few storms. Winds behind the front will gust in the 20kt to the locally 30kt range through the remainder of the TAF period. Passage of the front will also bring another round of low MVFR to IFR ceilings across the mountains.

EXTENDED AVIATION OUTLOOK... Rain showers will persist through tonight and gradually end by around sunrise on Saturday. Winds will gust between 20kt and 30kt from the north through much of the day on Saturday, with decreasing clouds through the morning and early afternoon. Speeds will decrease Saturday evening to 10kt or less around sunset. Dry weather and VFR conditions are expected Sunday through Tuesday.

Rnk Watches/Warnings/Advisories

VA...None. NC...None. WV...None.

DISCUSSION...NF AVIATION...NF