Frost Advisories, Freeze Warnings Issued for Monday Night

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Freeze warnings are shown in purple, with frost advisories in blue (National Weather Service).

Cover the plants, sensitive bushes, crops, and small trees tonight if you have any! The National Weather Service has issued frost advisories and freeze warnings in place for all of our region.

These advisories and warnings take place from midnight through 10 a.m. Tuesday. Frost advisories are in effect for basically anywhere that is not particularly mountainous – areas west of I-79. Freeze warnings are in effect for counties including, but not limited to Nicholas, Webster, Pocahontas, Randolph, and Upshur counties. Preston and Tucker counties are not included in neither the frost advisory or the freeze warning because their planting seasons have already concluded.

Temperatures will drop down into the middle 30s tonight in the lowlands, thanks to a west-northwest wind flow ushering in much cooler conditions with the passing of a cold front last night. As we roll into Monday night, the skies will clear, and the winds will be very light. This will allow maximum cooling from the surface, meaning temperatures will plummet. I would not at all be surprised to see a few 20s in the mountains tonight!

Just because the air temperature says 35 degrees does not mean it will not frost. Most temperature recordings are taken above ground – usually around 6 feet high. Cold air sinks below warmer air, so colder air is at the ground than even at 6 feet. It is pretty common in our neck of the woods to see air temperature recordings of 35 degrees with a light frost on the ground.

Tuesday night is looking similar in terms of chill. Don’t be surprised to see more advisories and warnings issued for that night as well.

For a complete list of the definitions of different watches, warnings, and advisories, click here.

The Snow Season in Central West Virginia

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Despite the warm temperatures we are currently seeing in central West Virginia, the season of snow is right around the corner! In fact, as recently as 2012 have we seen a measurable snow before Halloween!

Earliest First Snows in Our Region

The top 10 earliest measurable snowfalls recorded for both Charleston and Elkins.

As far as history is concerned, the mountain counties have already seen snow this early in the year, and the lowlands are not far behind. Elkins’ earliest measurable snow has taken place on October 6th, while the earliest measurable snow for Charleston occurred on October 19th. As far as the last three years, Charleston received its first measurable snow on November 13th (2014), December 18th (2015), and November 19th (2016). For Elkins, its first measurable snow the last three years have taken place on November 18th (2014), December 3rd (2015), and November 19th (2016).

The top 5 latest first measurable snows of all-time in Charleston are February 25th (1950), January 2nd (2012), January 1st (1995), December 20th (1965), and December 18th (2015). The top 5 latest first measurable snows of all-time in Elkins are December 28th (1931), December 15th (1946), December 11th (1947), December 8th (1941), and December 4th (1990).

Snowiest Months

If you are not a fan of the snowy season, then 2017 has been a good year to you. During the entire year, Charleston has seen only five days with measurable snowfall. For Charleston, that is the second lowest number of measurable snow days in the city’s history, only to the year 1949 (4). Elkins has seen 18 measurable snow days so far in 2017, which is currently tied for the lowest number of days of measurable snowfall with the year 1932.

On the flip side, Charleston has seen as many as 18 days of measurable snow in a single month, which occurred in January of 1978. 17 days of measurable snow in a single month were observed in January 1985 and January 1979. The highest number of days with measurable snowfall in a single month in Elkins is 23 set in January 1985. Impressively, 22 days was reached in February of 1964 (Only 29 days), and 22 was also reached in January 1978. The highest number of days with measurable snowfall in a year in Charleston is 42 days, which was set in 1995, followed by 41 (1978), 40 (2010), and 38 (1985, 1979, 1977, and 1960). For Elkins, the highest number of days with measurable snowfall in a year is 65, which was set in 1981, followed by 63 (1979), 61 (1989), 58 (1970), 57 (1968), and 56 (2010).

Average Snowfall in the Mountain State

Average snowfall per year (State Climate Office of North Carolina).

On average, Charleston receives about 36″ of snowfall during a year, while Elkins averages around 83″.

The large difference between the two cities has a nearly direct correlation with elevation. During the winter months, it is very common for an upslope snow effect to take place on the mountaintops of the Appalachians. This effect takes place when moisture in the form of clouds from a source of water (usually the Great Lakes for our region) is pushed up over the mountaintops and condenses, causing snow to fall when temperatures are sufficiently cold. Upslope adds significantly to the average snow total of an affected town, and Elkins is certainly one of those affected.

Breaking it down by month, Charleston averages about 1″ of snow in November, 6″ in December, 11″ January, 10″ in February, 6″ in March, and 1″ in April. Elkins averages about 1/2″ in October, 5″ in November, 17″ in December, 24″ in January, 19″ in February, 12″ in March, and 5″ in April.

Record Snowfall in the Mountain State

According to the West Virginia Encyclopedia, Terra Alta holds the record for most snow to fall in a single month, with 104 inches falling in January 1977. The encyclopedia says that the most snow to occur during a 24-hour period is 35 inches at Flat Top, on the Mercer/Raleigh County line on January 27-28th, 1998, an average of about 1.5″/hour for 24 hours. The most snow to occur during a single storm is 57 inches, which took place during the great post-Thanksgiving snowstorm of 1950 in Pickens in Randolph County, WV.

In terms of snowfall from a single event, the most snow to fall in Charleston is 23.3″, which occurred about 20 years ago on January 8th, 1996. More recently, 18.7″ of snow fell on January 23rd, 2016, and 12.8″ of snow fell on December 20th, 2009. In Elkins, a whopping 28.2″ of snow fell on November 26th, 1950, the most snow ever to fall in the city. More recently, 22.5″ of snow fell on February 15th, 2014, and 21.6″ of snow was on the ground on December 20th, 2009.

 

Lastly, I’m going to end this post with a list of some of the most common winter weather advisories, watches, and warnings, and their meanings to refresh everyone on the differences between each. Expect a winter forecast sometime in November.

 

Different Winter-Related Watches and Warnings and their Meanings

Winter Storm Watch

A Winter Storm Watch is issued when there is the potential for significant and hazardous winter weather within 48 hours. It does not mean that significant and hazardous winter weather will occur…it only means it is possible.

Significant and hazardous winter weather is defined as a combination of:
1) 5 inches or more of snow/sleet within a 12-hour period or 7 inches or more of snow/sleet within a 24-hour period
AND/OR
2) Enough ice accumulation to cause damage to trees or powerlines.
AND/OR
3) a life threatening or damaging combination of snow and/or ice accumulation with wind.

The snow/sleet criteria for a Winter Storm Watch for the five westernmost counties (Allegany, Mineral, Grant, Pendleton, and Highland) is higher (6 inches or more within a 12-hour period; 8 inches or more within a 24-hour period).

Blizzard Warning

A Blizzard Warning means that the following conditions are occurring or expected within the next 12 to 18 hours.
1) Snow and/or blowing snow reducing visibility to 1/4 mile or less for 3 hours or longer
AND
2) Sustained winds of 35 mph or greater or frequent gusts to 35 mph or greater.
There is no temperature requirement that must be met to achieve blizzard conditions.

 

Winter Storm Warning

A Winter Storm Warning is issued when a significant combination of hazardous winter weather is occurring or imminent.

Significant and hazardous winter weather is defined as a combination of:
1) 5 inches or more of snow/sleet within a 12-hour period or 7 inches or more of snow/sleet within a 24-hour period
AND/OR
2) Enough ice accumulation to cause damage to trees or powerlines.
AND/OR
3) a life threatening or damaging combination of snow and/or ice accumulation with wind.

 

Ice Storm Warning – ¼ inch or more of ice accumulation.

 

Freezing Rain Advisory – Ice accumulations of less than 1/4 inch.

 

Winter Weather Advisory – A Winter Weather Advisory will be issued when 2 to 4 inches of snow, alone or in combination with sleet and freezing rain, is expected to cause a significant inconvenience, but not serious enough to warrant a warning.

For this particularly snow event in 2016, several winter weather advisories (blue) and winter storm warnings (pink) were issued by the NWS.

Freeze Watch – A Freeze Watch is issued when there is a potential for significant, widespread freezing temperatures within the next 24-36 hours. A Freeze Watch is issued in the spring at the start of the growing season (when it is late enough to cause damage to new plants and crops).

 

Freeze Warning – A Freeze Warning is issued when significant, widespread freezing temperatures are expected. A Freeze Warning is issued in the spring at the start of the growing season (when it is late enough to cause damage to new plants and crops).

 

Frost Advisory – A Frost Advisory is issued when the minimum temperature is forecast to be 33 to 36 degrees on clear and calm nights during the growing season. A Frost Advisory is issued in the spring at the start of the growing season (when it is late enough to cause damage to new plants and crops).

 

Wind Chill Advisory – A Wind Chill Advisory is issued when wind chills of -5F to -19F are expected east of the Blue Ridge Mountains, and when wind chills of -10 to -24F are expected along and west of the Blue Ridge Mountains and in Frederick and Carroll Counties in Maryland.

 

Wind Chill Warning – A Wind Chill Warning is issued when wind chills of -20F or lower are expected east of the Blue Ridge Mountains, and when wind chills of -25F or lower are expected along and west of the Blue Ridge Mountains and in Frederick and Carroll Counties in Maryland.