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Winter Storm Threat: February 17-18 (Only/Final Call)

A nail-biter between warming low-to-mid level air and marginal temperatures/wet bulbs at the surface. At least the Sun won’t be fighting most people during most of this event from D.C. northeastward.

Biggest uncertainty lies with snowfall rates, especially in areas that have marginal wet bulb temperatures at or above freezing (i.e. anywhere south of the Frederick, MD to Philadelphia line, generally speaking). That wet bulb freezing line has also been creeping further north than what I had anticipated when looking at the setup over the past few days. We’ll see it the wet bulb temperature or the snow/sleet rates win.

Winter Storm Threat: February 8-9 (Final Call)

I ended up going more bullish with the southern fringe of the different snow contours east of the mountains and across south-central Pennsylvania, otherwise my thoughts are pretty similar to yesterday.


Still looking at a fair amount of uncertainty regarding snow accumulation east of the mountains due to the very warm temperatures leading into this event. A good pasting of snow is expected once temperatures cool down early Thursday morning, but a 1-2 hour shift in either direction with the introduction of colder air could add or remove some 1-4″ of snow. That being said, once the changeover to snow is made, it will be snowing quite hard, and heavy snow can overcome marginal surface temperatures.

Winter Storm Threat: February 8-9 (Initial Call)

This time it’s the 40N crew that will cash in with this upcoming snow storm. After a very mild Wednesday along the East Coast, temperatures will come crashing down overnight as a disturbance develops over Virginia and tracks just south of Long Island.


Ultimately, the strengthening and position of the surface low will have a large impact on how far north/south the 1″+ snow amounts end up. The snow will also be battling against a very warm antecedent air mass that will keep most spots as rain for at least the onset of precipitation. This means places like D.C. and Baltimore will struggle to change over to snow overnight. Heck, D.C. stands a risk of never changing over to snow at all Thursday morning if the more northern model solutions are correct.

As the initial storm system moves out Thursday morning and early afternoon, a second upper-level vort. max will slide through the Mid-Atlantic. This could trigger snow showers across more of the Mid-Atlantic Thursday afternoon and evening. Most places around/south of D.C. will still be too warm to see this light snow stick, but a little “snow TV” is better than nothing… I think?

Winter Storm Threat: February 8-10 (Only/Final Call)

This storm has a complicated setup. You have multiple surface lows within a broader upper-level trough, marginal surface temperatures, and large discrepancies in QPF placement between the models.

Temperatures along and east of I-95 are the most uncertain, which are expected to be in the low-to-mid 30s through most of the event. Areas north and west of I-95 will start above freezing, and will cool to at or below freezing depending on how strong the snowfall rates are tonight.

Snowfall rates will be one of the most important factors in determining which areas see 4-8 inches, and which areas get 1-4 inches. The best rates are likely to be along the Maryland/Pennsylvania border into southern New Jersey.


The intensity of the initial coastal low, the secondary coastal low development, the strength of the low over the Great Lakes, and the timing of the strengthening and weakening of these lows are wreaking havoc on the QPF output on the various models.

I tried my best to offer a realistic compromise between the differences in QPF, while also accounting for the surface temperature and snowfall rate issues. I could definitely see a tighter gradient between accumulation amounts than what I have on the map.

Winter Storm Threat: February 26-27 (Only/Final Call)

It’s time for the southern folks to finally cash in this season. Some spots in North Carolina and southeastern Virginia are expected to get as much snow as they typically get in a year, so this should be a fun storm for them. I battled a bit in the placement of the 1″ and 2″ contours on the north edge of things, as there is a wide range of solutions in that department still. The rain/snow line across North Carolina is another big hurdle, but it seems the warm nose will be around 850mb, which made sorting it out on the models easier.


I expect a couple of 12+” reports out of this in North Carolina and southeastern Virginia. The northern edge of the 1-2+” has equal risks of busting high/low.

Winter Storm Threat: February 21-22 (Only/Final Call)

Lots of uncertainty with this system. How much precip. falls as snow before the changeover, timing of the changeover, rates during the daytime hours, etc. The only thing that’s not really in question will be the surface temperatures at the start of the storm. Cold, cold, cold.


Models overall show a little more potential to get higher totals than lower totals east of the Appalachians.

My brain is done. k bye.

Winter Storm Threat: February 16-17 (Final Call)

Cut back on totals in central and eastern Pennsylvania a little bit, and tweaked 8-12″ contour ever so slightly. On the south end of things, I lowered the snow+sleet totals in North Carolina east of the Appalachians and into far southeastern Virginia. Still a solid 5-10″ event around the greater D.C. region.


Would have been interesting if people didn’t have Monday off… onset around D.C. is during the afternoon rush hour. At least we get to avoid that fiasco this time around. Should end near or slightly before daybreak for most. Enjoy your fresh pow pow.