Browse Tag

sleet

Snowfall Verification for Jan 21

This was an interesting one to watch unfold…

 
Cold air damming allowed for more snow at the onset of the storm than what I was expecting, which resulted in broader 1-2 inch coverage east of the mountains in central VA, MD, DC and southern NJ. This also allowed the freezing rain and sleet to work a bit further south. The back end of the system also had a surprise up its sleeve, bringing up to seven inches of snow to the Pittsburgh area. The snow underperformed a bit along the southern edge in the mountains where warmer temperatures led to more mixing and plain old rain.

The higher snow totals were captured pretty well for the most part, especially along the southern edges of the 2-4 inch and 4-8 inch contours. The pink indicates areas that received 0.1-0.25+ inches of sleet and/or freezing rain (which was a bit trickier to contour due to the nature of the reports).

I knew the snow was a bit of a risk in the CAD region, but I didn’t pull the trigger on it and ended up paying for it. I’m going to give this forecast a grade of B-… the northern areas were quite good, but the southern areas suffered a bit.

—–

I have a new map design that I will roll out during the next snow event. On top of being a larger image, it also has county lines and interstates for easier interpretation.

Winter Storm Threat: Jan 31 – Feb 2 UPDATE

I made some changes in the Wednesday forecast to account for warmer surface temperatures… not too much of a shift, but it could change the plans for a significant amount of Maryland workers.

 
We’re still looking at 0.1-0.2″ of freezing rain along the northern parts of the rain area before it switches over around the morning rush hour in areas. Hopefully there will be enough normal rain to keep the big freezing rain from causing too much fuss in the major metro and commuter areas.

Winter Storm Threat: Jan 31 – Feb 2

The strength of the cold air damming will be a big player in determining where the different areas set up. Based on recent guidance and trends, I’ve come up with the following maps depicting the first event (with light precip. totals over most of the region) and for the second event (which will have QPF in the 0.4-0.8″ range for the most part in MD/North VA and 1″+ QPF possible in PA):

 
Please note the word MOSTLY in the mixed precipitation and rain categories. This indicates that these areas will fluctuate a bit during the events. Some mixed precipitation is also possible in the snow areas (in the 1-2″ contour and maybe even in the southern parts of the 2-4″ contour).