WxUSAF

Huh?? 6z? Looks pretty rough to me.

Healthy looking snow squall near the m/d line. Heads up @mappy @psuhoffman @losetoa6 @HighStakes

Agreed. That’s pretty tasty as is and a tick or two away from top tier longwave pattern for mid Atlantic snowstorms.

Wife reports flurries in Columbia a little while ago

As I recall, Boxing Day storm had some warnings of a fail ahead of time. Was kind of on/off the model progs, we were always kind of on the edge, Miller B risk, etc. March 2013 was just a complete out of nowhere gut punch. I’ll never forget going to bed with this wall of snow approaching on radar, people on here in central VA seeing heavy snow and already exceeding forecast amounts. I told my wife I thought we’d get more than expected. Then I woke up the next morning and it looked like Monday morning with like 1” of slush and I just was dumbfounded.

HMs take on this discussion

@tombo82685, yeah will be interesting to see how things look in 48-72 hours. GEFS starts moving the TPV south on the 28th, and not coincidently, that's when the EPO ridge goes up. That's the mark on the wall. 6z GEFS actually accelerated things a bit relative to the last few runs previously.

Trend for strong southern stream shortwaves rolling across the country the last 2 months is clear. Have to think odds of a widespread big dog storm is higher than normal when you add in the trend of HL blocking. Still maybe less than 50-50 odds, but still above normal.

Bob, I agree that I think we'll get there eventually. Whether it's on Dec 29 like the GEFS thinks, some compromise of Jan 3rd-ish, or probably Jan 7 or after as EPS might suggest (via extrapolation), I don't know. I'd probably chicken out and lean toward a compromise of the first few days of January if I had to pick. One thing I came across in reading this morning is that there's a pretty huge snow cover deficit in Eastern Europe and western Russia. Always a bit of chicken-and-the-egg situation, but that might help bolster the Scandanavian ridging that keeps reloading the east -NAO and occasionally west -NAO and can be seen clearly on your CFS map above.

GEFS and Eps diverge significantly after D10 as has been said, but they’re very similar at D10. One subtle difference between them at D10 is the one that loads a good pattern for us on the GEFS and bad on the Eps. On the Eps at D10, the TPV is stronger and slightly more NW (poleward) relative to the GEFS. GEFS has the TPV a bit weaker and then moves it southward over Hudson Bay after D10. Eps keeps it at high latitudes and leaning toward Alaska. The tropical forcing and the wave 2 hit on the strat vortex peaking around Xmas suggest an evolution like to GEFS should happen eventually, but wouldn’t be surprised if it’s after the new year and not a few days before like the GEFS has.

Based on the forecast I’d wager we end the month +1-2F. Depends how many torch days we get. What’s indisputable is that our warm days are almost always warmer than the cold days are cold .

Yes. Think it happened early this year.

I can’t get plots for this while I’m on my phone, so it’s just memory, but I think GEFS picked up the early Novie EPO period and the secondary one in late Nov/early Dec earlier than Eps.

BWIs new asphalt tarmac certainly seems to be having an influence.

^thats certainly been true for the EPS in the last 8 weeks. GEFS has sniffed it out from range more accurately it seems. GEFS can rush it though.

Actually by the end of the GEFS run its a good pattern for snow, and it’s a step or two away from a VERY good pattern for snow

Don’t scare the weenies Bob. 12z GEFS looks pretty good towards NYE actually. Faster transition to a workable Pac than previous runs as well.

While I’m here in California, I’m facing west and huffing and puffing as often as I can to weaken the Pac puke flood. You’re welcome.

Yup, looks like 5-6 cold+dry days coming up and then a week of AN Pac puke and then probably things start reshuffling. It is nice that we are seeing the exit door from the wretched Pac open before we even walk through the entrance. But need some patience for the next 2 weeks. With the clear tendencies toward HL blocking and an active pattern this year so far, I remain pretty bullish on at least an “average” winter snowfall wise.

^thats a weak amplitude wave however. If those strat forecasts are right, we could get an EPO driven arctic shot just before New Years due to the strong wave 2 hit on the strat PV.

You mean 2 W Elkridge?? That’s me... At least sometimes, my neighbor also gets reported as 2 W Elkridge. Definitely looks like the fall line was a drop off as usual. I’m about to drive to BWI, so will be interesting to see the falloff.

BWI and IAD numbers seem paltry. They both adjusted up last week, so maybe they will again.

It would with a +PNA probably. With a -PNA battling a SE ridge, it could set up overrunning (and cutters...).

8am PWS from LWX Public Information Statement Spotter Reports National Weather Service Baltimore MD/Washington DC 804 AM EST Mon Dec 16 2019 The following are unofficial observations taken during the past 6 hours for the storm that has been affecting our region. Appreciation is extended to cooperative and CoCoRaHS observers, Skywarn spotters and media for these reports. This summary also is available on our home page at weather.gov/baltimore ********************STORM TOTAL SNOWFALL******************** LOCATION STORM TOTAL TIME/DATE COMMENTS SNOWFALL OF /INCHES/ MEASUREMENT DISTRICT OF COLUMBIA ...District of Columbia... National Zoo 1 WSW 0.2 700 AM 12/16 Trained Spotter MARYLAND ...Allegany County... Cumberland 1 SSE 1.6 730 AM 12/16 Trained Spotter Ridgeley 1 NW 1.3 445 AM 12/16 Trained Spotter ...Anne Arundel County... Severn 2 SSW 0.2 610 AM 12/16 CoCoRaHS Bwi Airport 0.1 725 AM 12/16 Airport ...Baltimore County... Glyndon 1 WSW 1.5 740 AM 12/16 Trained Spotter Reisterstown 1 SW 1.4 734 AM 12/16 Trained Spotter Bentley Springs 1 E 0.8 730 AM 12/16 Trained Spotter ...Baltimore City... Pimlico SE 0.8 708 AM 12/16 Trained Spotter ...Carroll County... Westminster 2 SE 1.8 740 AM 12/16 Trained Spotter Wagners Mill 1 ENE 1.5 650 AM 12/16 Trained Spotter Eldersburg 1 SE 1.2 645 AM 12/16 Trained Spotter Manchester 1 SSW 1.1 700 AM 12/16 Trained Spotter ...Frederick County... Adamstown 1 ESE 2.1 710 AM 12/16 Trained Spotter Bloomfield 2 WSW 2.0 655 AM 12/16 NWS Employee New Market N 1.3 530 AM 12/16 Trained Spotter New Market 2 NW 1.3 730 AM 12/16 Trained Spotter ...Harford County... Bel Air 2 W 1.2 645 AM 12/16 Trained Spotter Forest Hill 3 SW 0.8 615 AM 12/16 Trained Spotter ...Howard County... Sykesville 2 SSE 1.4 700 AM 12/16 CoCoRaHS Simpsonville 1 SSE 1.1 645 AM 12/16 Trained Spotter Elkridge 2 W 1.0 650 AM 12/16 Trained Spotter Columbia 2 N 0.6 615 AM 12/16 CoCoRaHS Elkridge 0.6 630 AM 12/16 NWS Employee Laurel 1 NNE 0.1 600 AM 12/16 CoCoRaHS ...Montgomery County... Norbeck 1 ESE 1.3 700 AM 12/16 CoCoRaHS Damascus 1 SE 1.2 700 AM 12/16 Trained Spotter Germantown 5 NNE 1.2 600 AM 12/16 CoCoRaHS Clarksburg 3 E 1.1 629 AM 12/16 Trained Spotter Aspen Hill 1 SW 1.0 720 AM 12/16 Trained Spotter Gaithersburg 3 NE 1.0 700 AM 12/16 CoCoRaHS Germantown 2 WSW 1.0 730 AM 12/16 Trained Spotter Olney 1 ENE 0.8 545 AM 12/16 CoCoRaHS ...Prince Georges County... Beltsville 1 NNW 0.6 645 AM 12/16 CoCoRaHS Oxon Hill 0.2 700 AM 12/16 Co-Op Observer Oxon Hill 1 W 0.2 700 AM 12/16 CoCoRaHS ...Washington County... Boonsboro 3 NNE 1.6 600 AM 12/16 Trained Spotter Hagerstown 1 ENE 1.6 700 AM 12/16 CoCoRaHS Williamsport 3 ENE 1.2 534 AM 12/16 CoCoRaHS VIRGINIA ...Arlington County... Reagan National Apt 0.1 655 AM 12/16 Airport ...Clarke County... Berryville 1 NNW 1.0 555 AM 12/16 Trained Spotter ...Fairfax County... Herndon 2 ENE 0.5 630 AM 12/16 Trained Spotter Herndon 1 NNE 0.5 600 AM 12/16 NWS Employee ...Frederick County... Winchester 4 ENE 1.0 546 AM 12/16 Trained Spotter Stephens City 2 E 0.6 635 AM 12/16 Trained Spotter ...Highland County... Mill Gap 1 SW 0.4 600 AM 12/16 Co-Op Observer ...Loudoun County... Leesburg 1 ESE 0.5 515 AM 12/16 NWS Employee Dulles International 0.4 700 AM 12/16 Airport Purcellville 0.4 355 AM 12/16 NWS Employee WEST VIRGINIA ...Berkeley County... Bunker Hill SE 1.9 718 AM 12/16 Trained Spotter Martinsburg 2 E 1.7 700 AM 12/16 NWS Employee Martinsburg Arpt 1 N 1.5 600 AM 12/16 Trained Spotter Inwood 1 S 1.5 513 AM 12/16 Public ...Grant County... Kline Gap 2 ESE 1.0 615 AM 12/16 Trained Spotter ...Jefferson County... Halltown 2 W 1.8 745 AM 12/16 Trained Spotter Ranson 2 NE 1.8 745 AM 12/16 CoCoRaHS Millville 1 ESE 1.5 656 AM 12/16 Trained Spotter Bloomery 3 SSE 1.2 705 AM 12/16 Trained Spotter Rippon 2 W 1.0 455 AM 12/16 NWS Employee **********************24 HOUR SNOWFALL********************** LOCATION 24 HOUR TIME/DATE COMMENTS SNOWFALL OF /INCHES/ MEASUREMENT MARYLAND ...Anne Arundel County... Severn 2 SSW 0.2 610 AM 12/16 CoCoRaHS ...Howard County... Sykesville 2 SSE 1.4 700 AM 12/16 CoCoRaHS Laurel 1 NNE 0.1 600 AM 12/16 CoCoRaHS ...Montgomery County... Norbeck 1 ESE 1.3 700 AM 12/16 CoCoRaHS Germantown 5 NNE 1.2 600 AM 12/16 CoCoRaHS Gaithersburg 3 NE 1.0 700 AM 12/16 CoCoRaHS Olney 1 ENE 0.8 545 AM 12/16 CoCoRaHS ...Prince Georges County... Beltsville 1 NNW 0.6 645 AM 12/16 CoCoRaHS Oxon Hill 0.2 700 AM 12/16 Co-Op Observer Oxon Hill 1 W 0.2 700 AM 12/16 CoCoRaHS ...Washington County... Hagerstown 1 ENE 1.6 700 AM 12/16 CoCoRaHS Williamsport 3 ENE 1.2 534 AM 12/16 CoCoRaHS VIRGINIA ...Highland County... Mill Gap 1 SW 0.1 600 AM 12/16 Co-Op Observer ***********************STORM TOTAL ICE*********************** LOCATION STORM TOTAL TIME/DATE COMMENTS ICE OF /INCHES/ MEASUREMENT MARYLAND ...Montgomery County... Aspen Hill 1 SW T 720 AM 12/16 Trained Spotter VIRGINIA ...Rockingham County... Dale Enterprise 1 ES 0.01 730 AM 12/16 Trained Spotter