Winter Storm Wednesday Arrival And Timeline

Winter Storm Wednesday Arrival And Timeline

Tuesday Evening February 19 2019

The weather map this evening is looking very impressive.  A large band of rain and snow dominate the eastern half of the nation. It’s developing Low Pressure in east Texas that will drive the snow. That will help to push a lot of tropical moisture north of the Gulf of Mexico our way. But it’s running into dry air. We have a set up for snow to be shown on radar for a few hours in the morning, but it may take a little longer to reach the ground.

The Winter Storm Warning in place will prove itself. High Pressure in Pennsylvania is currently blocking the progress, but that will move out of the way. In place will be air just cold enough for snow to begin at the beginning of the day. But it’s a little more interesting than that. If the snow takes an extra hour or two to reach you, that will be the atmosphere actually helping to generate more cold air to hang on longer.

 

Baltimore Weather Conditions at BWI 10 PM

  • Temperature = 35ºF
  • Dew Point = 9ºF
  • Relative Humidity = 33%
  • Wind: NE at 3 mph

 

The air is very dry!

That means the initial moisture on radar will dry (sublimate) before reaching the ground. That is called virga, and it shows up extensively on the radar simulation. This will also help to drop the temperatures a few degrees.

Cleaning up the noise in this display, we can see the NAM 3 Km Model break down of what should reach the ground.  That is what is shown in the sliders below. Compare that to the NWS onset graphic, and it does look to be an hour or two behind.

 

Winter Precipitation Simulation (Morning) —> slider

 

This is a good set up for evaporative cooling. Since the air is so dry, as the snow finally reaches the ground, it will cool the column of air by a few degrees.

So if you wake up and see temps barely near freezing, it should drop and then hold. That ‘hold’ will be important in the potential ice storm for the afternoon.

 

Temperatures at 7 AM

 

 

Colder At Temperatures at 11 AM

 

Winter Precipitation Simulation (Afternoon) —> slider

The colder air would allow ice to linger longer near and north of Baltimore. This is what I suggested for the past few days, as models often move the cold air out too soon. Here the NAM is jumping on that idea.

 

 

Winter Storm Warning (pink)

  • Southern PA, Cecil and Kent Co in MD have been included.
  • Winter Weather Advisory (purple): Southern Maryland and most of the Eastern Shore/Delmarva

 

Storm Notes:

  • Wednesday morning most of the area will see snow.  This includes Southern MD and Delmarva.
  • A burst of moderate to heavy snow could bring 1″/Hr at times.
  • Wednesday Afternoon: Snow will change to sleet and freezing rain from south to north. That change over will be around lunchtime between Washington and Baltimore.
  • Wednesday afternoon and evening: There will be icing across central Maryland
  • Wednesday night: The normally colder zones will have heavy icing
  • Thursday morning: It is possible that leftover ice has not fully melted or fallen off of trees in some areas even with warming and rain

 

 

 

My Call For Snowfall

  • The snowfall range really depends on the burst of snow and timing before the change over. Once the ice hits, the snow will compact anyway.
  • Sleet and freezing rain will be an additional problem to deal with through evening and possibly at night.
  • The bust potential would lean towards overachieving. I am still staying lower that possible due to the sleet.
  • Note that the initial snow intensity can reach rates over 1 inch per hour.

February 19 winter storm watch snow forecast map

Zone A:

  • 5″ to 8″ of snow. *Bust potential for less snow if the ice arrives sooner. The white circled region can get up to 12″ if they stay all snow longer.
  • The highest snow may be where it begins earlier allowing for more stickage before late morning.
  • This Zone will have the most snow and heaviest icing Wednesday night

Zone B:

  • 3″ to 6″ of snow. It will fall heavy at times in the morning. They higher end is based on heavy bursts… But if sleet moves in sooner, then the lower end will be more common.
  • Change over will be around lunchtime (between 11 AM and 3 PM).
  • I expanded this zone to include Kent, Queen Annes, and Caroline Countes.
  • Moderate icing in sleet and freeing rain
  • Should change to rain from south to north between 3 PM and 8 PM Wednesday.

Zone C

  • 1″ to 3″ of snow.
  • Faster change over to icing and then rain during the day.

 

 

ALL FITF  Apparel 

 

Please share your thoughts, best weather pics/video, or just keep in touch via social media

 

 

Keep In Touch Every Day

Just in case you don’t get all posts on your social media feed, stay up to date with the latest info…

Click here to sign up for email alerts…. Be the first to hear any new weather.

 


New Partner

Buchanan Kia of Westminster is a supporter of Just In Power Kids and Maryland Trek 6 in August 2019.


 

 

 

New Colors

We are giving 10% of each sale to Just In Power Kids: Providing FREE holistic care for pediatric oncology patients.

 

 

Related Links:

Winter Outlook

My Winter Outlook 2018-19: Multiple Nor’Easters and more snow

Interactive Snow Report

November 15 Snow Reports- Interactive Map Compared To My Forecast

Winter Snow And Top 5 Wet Years 

Snowfall Seasons at Beginning and End of Top 5 Wet Years In Baltimore

 

Related Winter Outlooks

Tropical Hints At Winter Snow

Solar Cycle: When Sun Spots Are Low We Get More Snow

El Nino Modoki May Enhance Snow Chances

Sweet Spot: Hitting 70ºF on Halloween is followed by more winter snow

Will A Wet Summer Bring A Snowy Winter?

 

Winter Weather Folklore

NOAA Winter 2018-2019 Outlook Explained: This Actually Supports Snow

Winter Outlook From Two Different Farmers Almanacs

Maryland Winters: Snowfall Maps and Baltimore Snow History

 

February 19th, 2019|Tags: , , , |