Cold, clear and Blizzard defined

Good morning Augusta.

This morning it is partly cloudy. Fog early. High of 27F. Winds from the SSW at 5 to 10 mph.

Tonight it will be mostly cloudy with a chance of snow after midnight. Fog overnight. Low of 19F. Winds less than 5 mph. Chance of snow 50%.

The readings from my own instruments are:

The humidity is 82% with a Dew Point of 14ºF and a wind chill of 21.4ºF.

The temperature Is 21.4ºF.

We have South Southeast winds between 0.0 MPH and 0.8 MPH.

Our Barometric pressure is 30.30 HPA 1016 and falling with a weather graphic indicating snow.   

We have a UV rating of 0 out of 16, sunset will be at 4:01 PM with Moon Rise at 6:29 p.m. EST and the moon phase is a Waning Gibbous.

For the pilots out there, Raw Metar readings are:

METAR KAUG 191253Z AUTO 20005KT 8SM CLR M07/M08 A2998 RMK AO2 SLP158 T10671083

Visibility is 8.0 miles/14.9 Kilometers with clear conditions.

We have had no snow or rain here in the past 24 hours.

Since we've had few decent snowfalls in the past 10 days, you might wonder what actualy constitutes a Blizzard.

What constitutes a Blizzard: from Weather.com

Blizzards

Blizzards are characterized by low temperatures (usually below 20°F) and accompanied by winds that are at least 35 mph or greater, there must also be sufficient falling and/or blowing snow in the air that will frequently reduce visibility to 1/4 mile or less for a duration of at least 3 hours.

A severe blizzard is considered to have temperatures near or below 10°F, winds exceeding 45 mph, and visibility reduced by snow to near zero.

Blizzard conditions often develop on the northwest side of an intense storm system The difference between the lower pressure in the storm and the higher pressure to the west creates a tight pressure gradient, which in turn results in very strong winds.

These winds combine with snow and blowing snow to produce extreme conditions. Storm systems powerful enough to cause blizzards usually form when the jet stream dips far to the south, allowing cold air from the north to clash with warm air from the south.

With the colder and drier polar air comes atmospheric temperatures cold enough for the development of snow, sleet, or freezing rain.

The Dakotas and parts of Minnesota were pounded by a succession of blizzards in the winter of 1996-1997. With few trees or other obstructions to reduce wind and blowing snow, this part of the country is particularly vulnerable to blizzards.

A continuation of the broad central plains that run from the Gulf of Mexico into Canada, this area often experiences severe blizzard conditions, with wind chills of 40°F below or more and whiteout conditions.

Another scenario occurs when a cold core low over the Hudson Bay area is displaced southward over southeastern Canada, the Great Lakes, and New England. As rapidly moving short waves, or areas of upward vertical motion and energy, move around the low, they collide with warmer air coming north from the Gulf of Mexico. This produces strong surface winds, lots of cold air advection, and extensive wintry precipitation.

In the southern central Great Plains, rapidly intensifying low pressure systems moving out of the Rocky Mountains can cause heavy snows and strong winds to the north, while to the south and east are thunderstorms and rain.

When cold, moist air from the Pacific Ocean makes it over the Rockies and into the Plains and warmer, moist air moves north from the Gulf of Mexico, all that is needed is a cold closed low aloft and a strong polar jet for potential blizzard conditions that may extend from the panhandle of Texas to the Great Lakes.