The Tools and Concepts for Forecasting Winter Precipitation

Introduction This informative forecast writing will focus on the weather forecasting tools and concepts that are used to predict winter weather events. There are various types of winter weather events that are analyzed and forecasted including mid-latitude cyclones, ice storms, lake-effect snows and sleet storms. Each of these will be discussed separately. In addition, bust … Read more

General Snow Forecasting

Historic snowstorm in North Texas on 2/12/2010. DFW recorded its greatest 24-hour snowfall of all time (12.5").

Snow is a precipitation type that results from the build-up of ice deposition upon condensation nuclei. The snowflake size is amplified as ice crystals join together as the crystals move in the wind. A common theme in ice crystal development is the 6-sized structure of the ice crystals. The chemical bonding of ice molecules produces … Read more

Snow to Liquid Equivalent and Associated Forecasting Pitfalls

The snow-to-liquid equivalent is the amount of liquid precipitation that is produced after melting snow. The temperature profile of the troposphere and the surface temperature are important factors that determine this value. The “average” snow-to-liquid ratio is 10:1. This is saying that if 10 inches of snow fell and that snow was melted it would … Read more

Dangerous Ice Storm Likely For Portions of the Plains and Midwest This Weekend

Update #4 [Sunday January 15 at 1 pm EST] – Tom Moore The multi-day ice storm continues in the nation’s heartland. So far, the greatest amount of ice, reported by the NWS from this storm (.50″-1.00″), has occurred from parts of northern Oklahoma to southern Kansas and into southwest Missouri. Dangerous conditions continue Sunday from much of … Read more

Beware of Snow Hype & Weather Hoaxes on Social Media

Beware of weather hype this winter. Know your weather source.

It’s that time of year… Winter. The season when those unrealistic snow and ice accumulation maps, for an unlikely event 10 days into the future, that often go viral on social media. So, I wanted to briefly discuss the nature of internet weather hype and how you can learn to recognize it. As the National … Read more

Atlanta’s Top 20 Snowstorms & Temperature Trends

Atlanta’s biggest snowfall events of all time are listed in the table below. The most snow ever recorded on a single day in Atlanta was on January 23, 1940 when 8.3 inches fell. The top 10 snowstorms in Atlanta have a median accumulation of 4.2 inches. View the full list We often hear the cliche: … Read more

Winter Storm Watch, Advisory, and Warning Criteria for North Texas

When it comes to winter weather, there is no shortage of advisory types.  This page is devoted to the four main winter weather products: Winter Storm Watch, Winter Storm Warning, Winter Weather Advisory, and Ice Storm Warning.  More specifically, I want to discuss the criteria used by the National Weather Service Office in Fort Worth, … Read more

What is dynamic cooling of the atmosphere?

In atmospheric dynamics, a negatively tilted upper-level trough tends to be stronger and much more dynamic, particularly if there is a closed upper low Both rising air and heavy precipitation (especially snow) work to cool the atmosphere from the top down.  This is called dynamic cooling and it is extremely efficient at turning an otherwise … Read more

Weather Myths: Too Warm for the Snow to Stick?

Before I begin this piece, I want to present a challenge.  The following chart shows the actual high and low temperatures for a full month in Atlanta, Georgia. *A condensed version of this writeup was also featured in the Douglas County Sentinel. Challenge: Can you spot the day with a historic snowstorm? During this particular … Read more

Birmingham’s Winter Storm Watch, Warning, & Advisory Criteria for Alabama

The National Weather Service has sole responsibility for issuing weather watches and warnings.  When it comes to winter weather, there are numerous advisory types ranging from Wind Chill Advisories to Ice Storm and Blizzard Warnings.  This page is devoted to the four main winter weather products:  Winter Storm Watches, Winter Storm Warnings, Winter Weather Advisories, … Read more

Atlanta’s Winter Storm Watch, Advisory, and Warning Criteria for Georgia

As a NOAA Weather-Ready Nation Ambassador, iWeatherNet strives to create educational content to help you be prepared for any type of severe weather; this includes winter weather. I wanted to take the opportunity to briefly review the various winter weather products issued by the Atlanta National Weather Service in Peachtree City. Other States Central Alabama: … Read more

Difference Between Single vs. Multiple Lake Effect Snow Bands

Radar image showing both single and multiple snow bands.

In an earlier article, we discussed the dynamics and thermodynamics of lake effect snow. In this post, we discuss the meteorological differences between single-band and multiple-band lake-effect snow events.  Keep in mind that all lake-effect snow events are fueled by moisture and latent heat flux from the relatively warm lake water; these fluxes are already … Read more

Lake-Effect Snow: The Physics of Colossal Snow

Lake effect snow formation illustration

One of the most awe-inspiring forces of nature is lake-effect snow. The amount of latent energy required to produce the lake-effect convection is astounding, and in some situations, snowfall rates can reach as high as 5 to 6 inches per hour.  In this article, we discuss the atmospheric physics, dynamics, and thermodynamics responsible for the … Read more