Tuesday, March 20, 2018

Beyond Snow-Trolling and Into Gaslighting: The European Model Gone Wild -OR- Update on the Allegedly Impending Start-to-Spring Snowstorm

European 12Z 3/20/2018 snowfall map for the mid-Atlantic valid 9PM EDT March 21, 2018 from Weather.us.

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OK, now I think the ECMWF ("European") model is trolling us -- no, wait, we're beyond trolling and into the realm of gaslighting -- but today's 12Z Euro buries the Baltimore/Washington corridor in a historic snowstorm with amounts in the 16 to 24-inch range -- figures that just aren't plausible in late March in our region.

Another version of the above map produced by a different entity:

European 12Z 3/20/2018 total snowfall map through hour 54 assuming 10:1 ratio ending 18Z 3/22/2018 from (I think) AccuWeather.com.

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While noting all the usual caveats about snow-to-liquid ratios this time of year, I'd like to point out that "DMV" snowfall map isn't that different than what the Euro showed five days ago:

European 12Z 3/15/2018 total snowfall map through hour 156 assuming 10:1 ratio ending 0Z 3/22/2018 as created by AccuWeather.com.

This is from the Euro 12Z run on March 15th -- six days or 11 runs ago. The implausibility of the 19 inches of snow at KDCA aside, the Euro has been remarkably consistent.

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Here is a CWG entry (with its present title and content) (link embedded): Washington's biggest snowstorm of the winter likely Wednesday, starting before dawn.

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Forecasted Snowfall Amounts (from midday Tuesday):

Below are two additional snow forecast maps. One is from our regional (Baltimore/Washington) National Weather Service (NWS) office, a.k.a., "Sterling" since the office is in Sterling, Virginia, and abbreviated "LWX." The other is from the Capital Weather Gang's afternoon update.

Expected snowfall for the Sterling (LWX) county warning area (CWA), Noon March 20th - 2AM March 22nd, 2018.

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Capital Weather Gang (CWG) snowfall forecast map for March 21, 2018.

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Precipitation totals so far:

As for today, So far, it has been mostly rain or a mix of rain and sleet in D.C. with sleet and snow in the suburbs and accumulating snow in the higher elevation exurbs and rural areas. The good news regardless is that we received some badly needed rainfall today. Precipitation totals so far:

KDCA: 0.81 inches
KBWI: 0.44 inches
KIAD: 0.72 inches
KDMH: 0.51 inches

Nearly all of this has been as rain but with some sleet and snow at Dulles and BWI. This is round one (the first storm). The next one is progged to come through later tonight into tomorrow and mostly in the form of moderate-to-heavy, wet snow.

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Radar imagery:

Sterling (LWX) NWS radar in standard composite mode looped 2:07PM - 2:46PM EDT March 20, 2018.

Three hours later as I post this, the radar looks more or less the same as the precipitation is forming over southern Maryland and the Virginia Northern Neck region and moving due north. The main upper level energy that will help to energize tomorrow's coastal low is still back over Tennessee / Kentucky.

NWS Great Lakes sector composite radar looped 1718 - 1828 UTC March 20, 2018.

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Current and forecast weather maps ...

NWS high-resolution surface map for a portion of the eastern United States valid 15Z March 20, 2018.

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NWS/WPC/NDFD surface weather map forecast for 12Z March 21, 2018.

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NWS advisories ...

We are under a winter storm warning for much of this part of the Mid-Atlantic region including the entire Metro D.C. and Metro Baltimore areas with "heavy snow" in the forecast for tomorrow (Wednesday).

Sterling (LWX) NWS county warning area (CWA) advisories map updated 5:06PM EDT March 20, 2018.

This map includes parts of the Wakefield (AKQ) area -- and when it is in a winter storm warning all the way down to the middle Chesapeake Bay, that's impressive. That is it late March, all the more so.

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Mt. Holly / Philadelphia NWS CWA advisories map updated 5:08PM March 20, 2018.

Lots of offshore storm warnings but none of those confusing "hurricane force wind warnings."

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PHI NWS CWA advisories map updated 3:47AM EDT March 20, 2018.

I posted this one from 11 hours earlier since it looks prettier -- because the winter storm warnings had not been raised for New Jersey, thus "coloring over" the coastal flood warnings and coastal flood advisories. (The more serious weather advisory product always takes precedence).

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GFS 12Z 3/20/2018 showing animated precipitation type and intensity as well as MSLP (unlabeled) for the Mid-Atlantic region in 3-hour time steps from 2AM March 21st - 5AM March 22, 2018.

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One good thing about this event -- even if it ends up a total "Snowquester" bust -- is that Boston should MISS OUT for once and NOT have the snow jackpot.

A second good thing is that it really won't take much snow to double D.C.'s current official seasonal total of 3.7 inches as measured at National Airport.

OK, that's all for now. I might update this entry with more info later if situation warrants.

Right now, I have some more work to do on an editing assignment. I'm staying late at the office -- it's a non-gym night.

--Regulus

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