textproduct: Blacksburg

SYNOPSIS

A strong cold front moves across the region tonight, ushering in gusty winds and much colder air for Thanksgiving Day. Cooler and dry conditions remain in place through Saturday. Rain chances, and even some snow return again by Sunday as another low pressure system approaches the region.

NEAR TERM /THROUGH THURSDAY/

As of 1210 PM EST Wednesday...

Key Messages:

1) Strong winds this evening into Thanksgiving morning.

2) Cold air settles in tonight, with lows below freezing for most.

A shot of cold air on strong low level winds arrives this eveninginto the overnight. Latest round of models suggest a 45-50kt jet at 8h moving across this evening. Given the holiday travel, have expanded the wind advisory to include the rest of the Blue Ridge into the Alleghanys including the I-81 corridor from Pulaski to Lexington, VA. Gusts of 35 to 45 mph will be common, with an occasional gust over 45 mph, especially higher ridges and between mountain passes. Though clouds will increase, airmass should be very dry, though would not be surprised to have some flurries across the mountains of WV tonight.

Winds will start to weaken during the day Thanksgiving but it will stay brisk. After lows in the 20s to lower 30s tonight, readings will only manage to rise 10 degrees in the mountains to the 30s, with mid 40s to near 50 east due to some downsloping aiding in warming.

Confidence is moderate to high in the near term forecast.

SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/

As of 100 PM EST Wednesday...

Key Messages:

1. Cold and windy Friday, only a few degrees warmer Saturday. Single digit wind chills possible Friday morning in the mountains.

2. Dry and mostly clear through the period.

A deep 500mb trough will pulling away from the area by Friday, and surface high pressure building into the area from the west, though the incoming airmass originates in southern Canada. This airmass will cause temperatures to drop significantly Thursday night into Friday morning, with most of the area seeing some of the coldest temperatures and wind chills since last winter. A tightening pressure gradient between the departing surface low and incoming high, with the combination of strong cold air advection and an 850mb jet between 40 and 45 knots, will result in gusty winds late Thursday night into Friday. HREF probabilities for wind gusts exceeding 40 mph Thursday night into Friday are around 60% for most of the mountains, and over 70% probabilities for gusts greater than 50 mph for the highest elevations in northwest NC.

As mentioned, temperatures will plummet by the end of the work week, in the wake of a cold front. Friday and Saturday will see temperatures in only the first percentile, relative to the 30 year climatology. Highs on Friday will barely escape the low 30s along and west of the Blue Ridge, with some places stuck in the 20s, though low 40s are expected in the east. Strong winds and cold temperatures will result in wind chills in the single digits in the mountains, possibly near/below zero at the highest peaks, like Mount Rogers VA, Friday morning.

Slightly warmer on Saturday, with highs in the upper 30s to mid 40s. Lows will be coldest Saturday morning, in the teens and 20s, as the surface high moves more overhead Friday night.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

As of 100 PM EST Wednesday...

Key Messages:

1. Wintry mix possible Sunday morning.

2. More precipitation chances Tuesday, with potential for more wintry precipitation.

A low pressure system will move from the southern Plains towards the Midwest and Great Lakes by early Sunday and push another cold front towards the area, bringing in enough moisture from the Gulf for widespread chances of precipitation. With cold enough air in place at the onset of the precipitation, will initially see a mix of snow, freezing rain, and rain, mainly for the higher elevations along and west of the Blue Ridge, before changing over to all rain. At this time, NBM probabilities of greater than 0.25" of 24 hour liquid precipitation accumulations through Monday morning are between 30% and 40% west of a line from Lynchburg VA to Danville VA. Western Greenbrier County WV has a 30% chance of a tenth of an inch of snowfall through Monday morning.

This system moves out of the area by Monday, though another low pressure system follows closely behind, after organizing in the Gulf Coast states and then tracking northeastward across the Carolinas and into the Atlantic Tuesday. The exact track of the low will influence the dominate precipitation type expected for the region, as that will impact where and for how long the cold air and moisture can mingle at the onset of the event. There is a large spread in temperatures for Tuesday morning, ranging from 25 degrees to 34 degrees at Blacksburg, VA, as one example to highlight the uncertainty in precipitation type this far out. Once this low moves away from the area, another surface high will move into the region, with another cold airmass, though not nearly as cold as late Thanksgiving week. High temperatures will range from the upper 30s to low 40s in the west, and upper 40s to low 50s in the east through the period, and lows in the 20s and 30s.

Extended Aviation Outlook

Strong northwesterly winds linger into Friday before finally relaxing for the weekend. High pressure will keep dry weather and VFR conditions in place through Saturday night. By Sunday, the next system arrives, which could bring sub-VFR conditions back to the area.

RNK WATCHES/WARNINGS/ADVISORIES

VA...Wind Advisory from 7 PM this evening to 11 AM EST Thursday for VAZ011-013>020-022>024-034-035. NC...Wind Advisory from 7 PM this evening to 11 AM EST Thursday for NCZ001-002-018. WV...Wind Advisory from 7 PM this evening to 11 AM EST Thursday for WVZ044-507-508.