Snow and Ice Map Posted for Major Winter Storm

I got my map templates back up and running. The first map is for how much snow I think will accumulate before the change over to sleet and then freezing rain.DCstorms_Snow_Accumulation_021516

The second map is how much ice accretion (trees, power lines, sidewalks, all untreated surfaces) from a pro-longed period of freezing rain. The time-frame of freezing rain is highlighted in yellow text on the map for the three zones.
DCstorms_Ice_Accumulation_021516

Bottom Line: Up to a quarter of an inch of ice could accumulate along the interstate 95 corridor before a change over to rain during the pre-dawn hours on Tuesday. The damage will have been done by the morning rush hour! What a mess!


Cold Wedge Likely to Hold Longer… Producing a Nasty Winter Storm

Sorry for the late update but my computer decided to completely die yesterday and I have spent hours recovering documents and I am slowly getting things back up and running.  For the sake of getting an update out I looked through the various models and found a snowfall map that I agree with the most (image courtesy weatherbell). 

wpc_snow_72_75_maryland

Why I think Winter Storm Warnings are needed along and west of  Interstate 95:

  • Snowfall ratios will start out high with the very cold air in place. Every flake will stick as surface temperatures are well below freezing.
  • Generally speaking I think 2 to 4 inches will fall across the Washington Metropolitan Area.  Locations along a line from Warrenton to Dulles Airport to Leesburg and Frederick Maryland could pick up to 5″ of snow before a change over to the dreaded freezing rain.
  • The probability of up to a quarter of an inch of ice on top of the snow is likely along and west of interstate 95 before the change over to rain  Tuesday morning.
  • Locations east of 95 could pick up to a tenth of an inch of ice (from freezing rain) before the change over to rain pre-dawn Tuesday.

 

Timing:

  • Snow begins between midnight and 3AM Monday (it will take some time to moisten up the very dry atmosphere in place).
  • Snow should fall through at least noon across the immediate Washington Area points north and west before a change over to freezing rain from southeast to northwest
  • Those of you in the sheltered valleys west of the Blue Ridge mountains should be prepared for significant icing with the potential for power outages as the winds pick up on Tuesday.