Winter Storm Warning Expanded To All Of Northern Maryland Until Thursday February 11

Wednesday February 10 2021

Rapid updates based on new information has led to even further expansion of the Winter Storm Warning. I also played catch up and bumped my call for snowfall map (below).

In my prior update, the National Weather Service had upgraded A Winter Storm Warning from Carroll County, westward. Their forecast put that ‘warning’ region into an expected snowfall range of 4 to 8 inches. Just a notch above my final call.

They have since added northern Baltimore, Harford, and Cecil Counties to complete the northern border of Maryland. This new region is for a 3 to 6 inch snowfall.

While southern PA is not included, I still see ‘over 4’ inches for Carroll Valley around Ski Liberty through York and Lancaster Counties.

The important thing here is that it will be cold enough for stickage on the roads, and accumulation has been trending up.

This will be mostly overnight and ending between 10 AM and noon Thursday.

THURSDAY MORNING UPDATE

Click to see: Weather Round Up Conditions, Next Snow Stays South, Weekend Ice Storm

Winter Storm Warning

Now for ALL OF NORTHERN MARYLAND

Why did they do this?

Two reasons:

First: 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.

As of 6 PM, some steady snow bands are expanding.

Road issues begin soon in the colder areas. The heaviest snow will arrive after 9 or 10 PM.

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 Northern Maryland to York and Lancaster County in PA.

I bumped this up to the 4 to 6 inch range, with some higher elevations possibly a little more. Ski Liberty in Carroll Valley through York and Lancaster.
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″ or 3″

South of Rt 50

Washington, Annapolis may start with snow, then mix, then end with snow. With marginal temperatures here, less snow will stick and accumulate. 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. More will be farther inland. 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.