Increased Snow: Winter Storm Warning Expanded In Maryland

Wednesday February 10 2021

In my last report in showed a new Snow Map where I increased my forecast in parts of north central Maryland to push the 6 inch threshold. If you have Faith in the Flakes, this is for you.

Since then, the National Weather Service has upgraded A Winter Storm Warning in this area. Their forecast put this ‘warning’ region into an expected snowfall range of 4 to 8 inches. This is just a notch above my final call.  There is a simple reason for this I’ll explain below.

Winter Storm Warning

Upgrade applies to Carroll, Frederick, Washington, and Allegany Counties in Maryland.

 

 

 

UPDATED AGAIN

Click to see: NWS EXPANDED THE WINTER STORM WARNING TO ALL OF NORTHERN MARYLAND

Plus New Higher Snow Totals

 

 

Why did they do this?

Simple answer: Temperatures being colder.

With lows in the mid 20s, the type of snowflake forming will be more ‘fluffy’ instead of our typical heavy and wet.

A ‘dry’ Dentrite Flake can have higher ratios than a standard 10:1 snow to water. It can be up to 15:1 or higher.

The same moisture can result in deeper snow depth when temps are colder than 28°F.

 

 

 

Moderate Snow Band Overnight

 

 

Arriving Early

The snow and sleet were reported around 3 PM in southern Maryland. This was ahead of schedule. No problem expected there with temps above freezing. This does support less virga and quicker onset.

 

It’s arriving fast… #FITF
Light snow and sleet already reported in southern Maryland this afternoon.
They might mix tonight.
Winter Storm Warning expanding in north central MD for more snow (after dark) pic.twitter.com/pZphYYo1Dh

— Justin Berk (@JustinWeather) February 10, 2021

European Model Full Animation: 7 PM Wed to 7 AM Fri

 

 

 

My Final Call For Snowfall (I showed in my prior post)

 

 

North of Rt 50: Increased snow just a little

• 2 to 4 inches
• Peak Snow Frederick County to York County. I have them in the 3″ to 6″, but there is model support for more.  Temps in the mid 20s will allow for flakes to ‘fluff up’ a bit more.
• The trend has been for this region to be in the bulls eye, so we might as well stick with it.

North Bay Coastal Area:

• Temps will be below freezing this time. That will allow the snow to fall and stick.  If you are south of I-95, you may end up closer to the lower end 2″

South of Rt 50

• Washington, Annapolis may start with snow, then mix, then end with snow. That cuts back the potential to 2 inches or less.

 

Southern Maryland

• May start with snow, then mix or simply have temps above freezing. Then end with snow. A coating or little more expected, especially near the water.  But more on the way in Part 2 Thursday night.

 

Compare Model Forecasts

Notice these numbers are higher than my call. I purposely stayed a little below the mark for higher confidence.

 

ECMWF Model

 

 

GFS Model

 

 

Canadian Model

 

NAM 3 Km Model

 

 

 

 

 

What’s Next?

 

Thursday Night:

I am skeptical of this hard southern push given the model bias I mentioned before. The snow should track north to Baltimore, but there will be more snow in Washington, Annapolis, and southern Maryland this Part 2.

 

Weekend Storm:

The latest plots show this as an ice storm. This will be a coastal track, but fast moving. This looks like we may be on the edge of the arctic air… I do think the developing snow pack from the next two systems may help us trend a little colder.

Timing:  Saturday ending Sunday morning.  Just a little faster and earlier than our first look.

 

Tuesday: Another Ice Storm? This will be an inland Ohio Valley Low

Depending on the snowpack established over the next few days, we could hold cold longer and have more moisture. This is the storm we don’t want.