Mid Atlantic: Forecast for October 29 Storm
There hasn't been a good storm since Hurricane Irene blew through the area but we are gearing up for winter and have our first storm just a few hours away.
Quick thoughts: Axis of heaviest snowfall will be over central PA and through New York State west of New York City. Philly area will mostly have accumulations 0-1 inch, 0-2 inches in suburbs, 3-6 toward Reading, 5-10 near State College through Central PA.
Check back here for complete snow map and predicted conditions after 10PM! *Check out Full Rundown Below- Remember Focus in Philly Metro Area
Just the Basics:
What: Miller A (Nor'easter)
When: Saturday AM- Saturday Late PM
Where: From West Virginia to Maine
How: Snow and Rain
What to Expect:
Light rain in the morning, moderate to heavy rain until afternoon, change to light to heavy snow from late afternoon to late night
There is a high bust potential for this forecast. Because the temperatures are only barely supportive of snow, the higher in elevation one is, the more snow and the more chance it will stick.
Basically, I think Philadelphia and the immediate suburbs will have trouble accumulating on sidewalks and roads because the surface temps will not/barely be below freezing. 30-40 miles North and West, accumulation will be easier and thus totals are higher. Most of NJ that is east of Philadelphia will not see much accumulation if any at all. It is very difficult for snow to stick on roads in October but snow will stick on trees creating dangerous conditions. All snow no matter how much will all melt by the end of the weekend almost everywhere.
There is <1d Celsius separating the NAM and GFS but that is significant since this means the difference between freezing and not freezing.
Another key is the setup of the deformation band as the Low pulls away. That is Philadelphia's only hope for accumulating snow.
Because of the high temperatures- snow ratios will be less than 10:1 (about 5:1 or less)
Some concerns: The model trend tonight (0Z) has been more east and weaker and thus better for the Philadelphia area in terms of more snow.
Take a look at 2Z HRRR:
Deformation band clearly over Philadelphia, Resulting snowfall:
Support by RR 03Z:
Omega Numbers certainly conducive for heavy snow, possibly thundersnow.
700mb Vorticity to show deformation band setup- it has been consistent
And look at shift east and difference it makes (not forecast- relative purpose):
Thanks for Reading!
I will continue to watch short range models tomorrow morning and update 6AM-7AM if necessary.