textproduct: Blacksburg

SYNOPSIS

An Arctic airmass with the coldest air so far this season was centered over the region. This airmass will move east of the area Wednesday with temperatures moderating for the second half of the week. Mountain snow showers this morning will come to an end with mainly dry weather prevailing for the remainder of the week. It will remain windy, with strong gusty west or northwest winds persisting until about Thursday before diminishing. Biggest concern the next several days will be the wind and potential for it to contribute to elevated fire danger.

NEAR TERM /THROUGH TONIGHT/

As of 700 AM EST Tuesday...

Key Messages:

1) Headlines: Winter weather related warnings and advisories have expired. Lingering effects expected until temperatures warm later this morning.

2) Precipitation: Mountain snow showers will come to an end this morning with dry weather areawide this afternoon and tonight.

3) Temperatures: Coldest airmass so far this season will maintain well below normal temperatures.

4) Winds and Wind Chill: This will be the most impactful element of the day. Blustery northwesterly winds will persist with sustained speeds of 10 to 20 mph and gusts of 25 to 35 mph. These winds combined with the cold temperatures to produce wind chills in the single digits and teens this morning, and teens to lower 20s tonight.

A highly amplified upper level trough over the eastern CONUS will continue to direct cold continental polar air into the Mid-Atlantic today. Observed 85H temps were -11 deg C in the regional upper air soundings and this should be about as cold as it gets before we begin to moderate aloft later this afternoon and tonight. Still getting some mountain snow showers and flurries due to upslope lift of moisture from a Lake Michigan, a feeder band that should break down this morning as winds turn westerly across the Ohio Valley.

Surface high pressure is poised to build in from the south and west later today and will become the dominant weather feature for mid-week. An upper level disturbance will cross the Ohio Valley and northern Mid-Atlantic tonight, bringing a period of cloudiness, but no precip this far south latitude. Biggest influence from this feature will be to tighten the pressure gradient over the area resulting in persistent windy conditions... especially across the ridgetops.

See fire weather discussion below, but the combination of the wind and very low dewpoints will result in good drying conditions. In spite of recent precipitation, watch for leaf litter to become crunchy and receptive to fire. Only exceptions will be areas that actually got some snow cover from this winter interlude...but for most of the CWA this was not the case.

Confidence is moderate to high in the near term forecast.

SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/

As of 300 AM EST Tuesday...

Key Messages:

1) Quiet and dry weather through the period.

2) Near seasonal temperatures expected.

A large high pressure system centered over Florida will build into the area on Wednesday, keeping dry conditions in place. A low pressure system and upper-level shortwave trough over the Great Lakes will be off to our north. While the moisture and vorticity stay north of the area, keeping our area dry, the pressure gradient between the high to our south and the low to our north will cause westerly winds to increase. Winds of 15-20 mph, and gusts of 30-40 mph will occur west of the Blue Ridge throughout much of the day and into Wednesday night. A dry cold front moves through Wednesday evening, turning winds more northwesterly. Combined with very low dewpoints, the strong northwesterly winds will cause an increased fire danger for the area with MinRH values around 30%. By late Thursday, the trough pushes east, and the gradient weakens, allowing winds to reduce. High pressure both at the surface and aloft build further into the area, with dry weather and quiet conditions continuing through the end of the period.

Seasonal temperatures return on Wednesday thanks to the initial southwesterly flow, with highs in the 50s/60s through the end of the week, with the highest elevations staying in the upper 40s Wednesday/Thursday. Lows each morning will remain chilly, in the 20s/30s.

LONG TERM /SATURDAY THROUGH MONDAY/

As of 300 AM EST Tuesday...

Key Messages:

1) Dry weather continues until late Sunday into Monday.

2) Temperatures climb to above normal for the weekend.

The high pressure system over the Mid-Atlantic weakens slightly Friday night as a warm front approaches from the west. This may allow a few showers to form on the western facing slopes due to the additional lift through Saturday. Any rain would be light, with PoPs under 20% Saturday afternoon as moisture will be limited. Upper- level ridging will continue to keep dry and quiet weather in place across the rest of the region through at least early Sunday as the next front arrives. The cold front is in association with a low pressure system in Canada north of the Great Lakes that will mostly pass by to our north. However, enough moisture and lift will move through to allow for some showers to form Sunday/Sunday night, though PoPs remain around 30-40%. The front quickly passes through, with a brief break from rainfall before yet another system over the southern Plains moves east. Confidence is low in the strength and location of the system, but some rain may move into our area late Monday. Models are currently indicating this system may mostly stay to our south, which is why PoPs are kept around 20-30% for now.

Temperatures will return to above normal this weekend, with highs in the 50s/60s each day, with even some low 70s for the Piedmont on Sunday ahead of the front. Overnight lows will be mainly in the 40s each night, with higher elevations staying in the 30s.

EXTENDED AVIATION OUTLOOK

Wind gusts will persist through Wednesday and reach up to 25-35 kts at times, otherwise VFR. By Thursday, high pressure moves overhead promoting clear skies and lighter wind speeds. Should be VFR into Saturday.

FIRE WEATHER

As of 400 AM EST Tuesday...

Key Message:

1) Elevated fire weather conditions expected next several days.

The combination of wind and low humidity will result in good drying conditions. In spite of recent precipitation, leaf litter will dry quickly, becoming crunchy and receptive to fire. The only exception will be areas that actually have some snow cover.

After today, temperatures will trend warmer. This warming will combine with the windy conditions and low humidity contributing to an increase in fire danger across the region. Wind gusts of 20 to 25 mph will be common with gusts up to 40 mph across the ridgetops Wednesday, and a very dry airmass will be in place Thursday. Both days are a concern with the peak potential being Thursday when temperatures return to normal contributing to higher vapor pressure deficits associated with the dry airmass.

Winds are forecast to diminish by Friday, lessening the effects of fire spread. However, Friday is expected to be the warmest day of the week with highs in the 60s, and still favoring good burning conditions.

RNK WATCHES/WARNINGS/ADVISORIES

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