Wednesday, January 20, 2016

WINTER 2016: "BLIZZARD OF '16" FORECAST

*Edited for brevity and clarity - no change to forecast thinking. I will point out the obvious - the further north you are, the snowier side of the scale applies, the further south one is, the opposite...

Stay safe and enjoy the weather. It'll melt before too long anyways (h/t snow-haters). 

TPB 


This has been a disappointing winter in terms of snow and cold so far - unless you are someone who would prefer to take up residence in Bermuda. If this includes you, read no further and go sit by the fire because what follows is my first (might be tweaked) and likely final forecast for the snowstorm beginning Friday AM and ending Saturday.

NEED TO KNOW / FORECAST FORMULATION:
  • THE FURTHER NORTH AND WEST YOU LIVE IN THE PIEDMONT = MORE SNOW, LESS ICE AND FREEZING RAIN. 
  • NO "PLAIN" RAIN EXPECTED 
  • EVERYONE WILL SEE SOME SNOW 
  • NOT EXPECTING POWER OUTAGES TO BE A MAJOR  ISSUE WITH THE EXCEPTION OF EXTREME S/SE ROWAN. IN OTHER WORDS CABARRUS AND POINTS SOUTH (CLT METRO) COULD BE DEALING WITH SEVERE ICING OF .50"+
Easy way to break down this storm for total accumulations is to look at total precip that I think will fall (APPROX 2") and then the expected thermal fields (air at different levels off the ground) and divvy that up by precip type. 

Only 3 possible categories for precipitation: freezing rain (ice), sleet, and snow. No rain expected.
  • Freezing Rain and sleet are the same in terms of liquid equivalence, i.e. .25" of sleet/freezing rain is .25" of water.  
  • Snow is trickier. Depending on the depth and temp of cold air (and a host of other factors) each snowstorm has a generally definable snow to liquid ratio. I expect about 8:1
    • Standard” is 10:1 (1 inch of snow = .1 inch liquid)
    • So .1" of liquid = .8" of snow OR 1 inch of rain = 8" of snow
Generally about 1.8" - 2.0” of liquid (precipitation) expected across the N.C. Piedmont, locally higher in spots if banding occurs, especially on Saturday if snow wraps-around.

Without Further Adieu or Map For Now,

Penn’s Storm Total Forecast
JANUARY 24TH – 25TH, 2016

DAVIE/ YADKIN / FORSYTH COUNTIES
12" - 14" SNOW
.25" SLEET
.10” (Glaze) of Freezing Rain

ROWAN CO.  (SALISBURY) & DAVIDSON 
 6" - 9" SNOW
.3” - .5” SLEET
                  .25” - .35” FREEZING RAIN       

That's all I got. Might make map later, might not, depending on my wife's tolerance of my weather obsession (very high so far, but also the first storm of the year...)