January 31 Afternoon Snow And Storm Update

Sunday January 31 at 5 PM

After what many have deemed a slow start this morning, snow has evolved and expanded this afternoon. It may have seemed light, but most areas should hit the expected snow for today (3″+) before any change over.

At 5 PM The National Weather Service Snow Report:

• Baltimore at BWI = 2.3″ (almost doubling our seasonal total)
• Washington (National) = 1.7″
• Washington (Dulles) = 2.2″

This is a long duration 2-part event.  That means it is spread out, then will come to an end on Tuesday.  There is more to go.  This evening there will be a change over to sleet moving north. Large flakes possible before the sleet and freezing rain.  Then we return with the coastal storm on Monday.

We are still under a Winter Storm Warning, but there could be a few hours or more where it seems like not much is happening.

I want to address  the analysis this afternoon, change over this evening, and Part 2 snow with the Coastal Low Monday.

At the bottom, I have an explanation for the Snowflake Sprinkles this morning,

The short story: I AM NOT CHANGING MY SNOW FORECAST.

Please recall my forecast breakdown:

• Today = Part 1: Snow 3 to 6 inches by evening.
• Tonight: Mixing and lull.
• Monday is Part 2: Snow returns mid day and afternoon. May be heavy at times with stronger winds. Additional Accumulation.
• Tuesday: Snow showers end as the storm moves away.   

THEN We measure the FINAL TOTAL

 

I will post my call for snowfall map again with the new model snow maps below.

 

 

Afternoon Set Up

Doppler Radar

Snow has appeared to fill in the bands and intensify this afternoon.   The energy has come in waves with bands of heavy snow, and lulls in between.

But the sleet and freezing rain is advancing north, as expected. At 5 PM this had reached south of Washington at the Pentagon and southern Maryland.

Note: Flakes may appear to grow larger right before the change to sleet. That is due to warmer air at cloud level partially melting the edges of flakes, and then they stick together to come down in clumps.

A ‘thump’ of snow is possible for a quick additional inch before a change in your area around the Bay.

 

Temperatures 

The Freezing Line has reached Easton and southern Maryland. Upper 20s seems to be holding tight around metro Baltimore, central Maryland, and into the mountains/southern PA.

 

Mesoscale Surface Map

The Primary Surface Low has been passing through southern Ohio.  As it gets closer and compresses up agains the Cold Dome in New England, there has been more lift in the atmosphere to enhance the snowfall.

This is also allowing the warmer air from the south to move north up the Bay.

 

 

Mesoscale Cloud Level

850mb to 700mb Map (around 3,000 Ft)

This is called Frontotgenesis, where we can see developing boundaries at cloud level.

 

 

Evening: Mixing From Snow To Sleet And Rain

NAM 3 Km 

Around 8 PM (wiggle room of 2 hours) the mixing should be spreading through Washington and Baltimore. At that time Annapolis should be rain, with snow lingering in the far northern suburbs.

By this point most of the region should have reached or be close to the Part 1 snow total of 3”+

By 11 PM we can see the snow line retreating north of Frederick to the Pennsylvania line.

 

 

Monday Morning

The tough part of this is forecasting a storm that has not formed yet. That is what tomorrow is all about.

• This will be in the ‘Lull’ as the Coastal Storm takes over.
• A light mix or even a few dry hours may appear as if the storm is over.
• We will watch for that coastal Low to intensity and pull back closer to the coast.

 

 

Afternoon and Evening Snow Returns

I expect the snow to return between 10 AM and 4 PM

Why such a large window? Because we are talking about a storm that has not formed yet, not knowing exactly where it will be.  A wobble of 50 to 100 miles can make a big difference in the arrival and intensity.

We will get snow and strong winds, but the models do differ.

European 

 

GFS Model

 

Canadian GEM Model

This model has been the outlier.  Here it brings the Low closest to the coast, but pushes the heaviest snow north of Philadelphia. At that time it keeps the warmer air and icy mix here a little longer.  Then changing over by evening.

Just because this model shows it, doesn’t mean it will happen.  I simply want to compare all the options.

 

Evening: Moderate to heavy snow reaches I-95. But mixing takes longer too return to snow on the bay. It will turn to all snow overnight before ending.

 

 

How Much Snow:

I know some of you have seen the models or other bloggers talking about the shift of the heavy snow northeast. I am not worried about that.  I have stayed with my snow forecast and it remains.  Even a pull back of snow on the models, still fits in with my consistent forecast.  Compare here:

My Forecast

Still The Same. We have mostly reached the 3″ I expected to this point.

 

European Model

This still fits with my forecast…

 

GFS Model

This still fits with my forecast…

 

 

Canadian Model

(This was always the highest and I felt too high) That bullseye shifted to The Poconos.

 

 

 

 

 

 

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