RodneyS

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA 1.4 0.6 0.4 -0.1 0.8 0.7 -0.2 0.2 0.1

The photo is gloomy, but last year's maximums were colder in Northern Virginia at this time of year. The average maximum at DCA during April 14-23, 2020 was 60.2, vs 64.7 this year. Moreover, there is a major warm-up coming this year. Last year, maximums at DCA during April 14-May 13 averaged only 63.6 -- the coldest DC average for those 30 days since 1882. Last year's DCA maximum on May 9th was 52 -- a record-tying low for that day.

Congratulations, NorthArlington10 1! By the way, I note that rhino16 nailed the DCA total. According to the Capital Weather Gang: "Out of more than 750 participants who entered our snowfall prediction contest, six were on the money, calling for 5.4 inches. Congratulations to: Keith Ernst Anne Kubelik Doug MacIntyre Heather Pierce David Sanders Margie Yeager" See https://www.washingtonpost.com/weather/2021/04/05/dc-snow-contest-winners-2021

So, with this year's 5.4 inches at DCA, we broke the 5-year minimum DC snow total by 3.6 inches, as the last five snow seasons at DCA have totaled just 34.1 inches, vs 37.7 during 1997-2002. However, we exceeded the 2-year minimum DC snow total by 0.9 inches, as the last two snow seasons at DCA have totaled 6.0 inches, vs 5.1 during 2011-2013.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA -0.5 -0.2 0.0 1.6 0.3 0.6 3.7 1.1 -1.6

My designated snow counters -- Vladimir Putin and Nicolas Maduro -- have informed me that a totally objective hand count reveals that the true amount that fell at DCA was 4.4 inches. By an amazing coincidence, that's exactly what I forecast! I have instructed Vlad and Nick to now do a similar hand count at the other three airports . . . I do note, however, that should my effort to steal win the contest fall short, NorthArlington101 has to watch his back at IAD. Should an additional 1.5 inches fall there, Cobalt would eliminate him.

I think it's now fair to say that both DCA and IAD have broken their high winter minimum temperature records set just last winter. DCA's record high winter minimum temperature is now 23 degrees, and IAD's is now 16. However, I discovered that way back in the winter of 1952-53, and more recently in the winter of 2001-02, the DCA minimum was 19. So, that 19-degree record DCA (and DC, back to 1872) high winter minimum stood until last winter, when it was broken by three degrees. This winter, that record high minimum was broken by another degree, as was also true at IAD.

I have based my 2021 forecasts on the 1981-2010 normals because otherwise I would just be engaging in informed speculation about the forthcoming 1991-2020 normals. It doesn't matter to me what the base is, as long as I know what it is. For example, you could set the base as historical average temperatures back to the 19th Century, in which case I would rarely submit a negative value. So, if I were running the contest, I would continue to use the 1981-2010 normals as the base until the 1991-2020 normals are officially established.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ____ DEN _ PHX _ SEA -0.1 -0.2 -0.1 0.8 0.0 0.2 0.9 0.6 -0.5

This does not affect the top of the leaderboard, but the 0.1 inch that DCA received on February 19th has been taken away. As far as I know, that 0.1 still stands, and so the official DCA total should be 5.4. Aside from that, the big change on the board is that Cobalt has eliminated H2O. H2O could still finish second, but he cannot pick up on Cobalt.

DCA is the champion of high minimums year-round. However, it's interesting to note that both DCA and IAD have added four degrees in the last decade to their respective high winter minimums. Coming into 2012, DCA's record high winter minimum was 18 degrees and IAD's was 11. Now, DCA's is 22 and IAD's is 15, with each quite possibly breaking those records by another degree this season.

In yesterday's Capital Weather Gang article, Ian was touting this morning as the day DCA and IAD would reach their 2020-21 seasonal winter minimums. That happened at IAD, with a morning low of 16, but failed to happen at DCA, where the seasonal minimum remains 23, which occurred on December 26th. If these minimums hold for the remainder of the winter, they would break the seasonal high minimum records established a year ago. For DCA, that is 22, and for IAD, 15.

Yes. Olaf is very much in the running. If he were to nail the three Baltimore-Washington airports with no more snow falling at RIC, his total departure would be only 1.6, which would definitely win it. Generally, if you are close to the lead with at least three (ideally four) positive departures, you're in the hunt.

RIC has received only a trace so far today, and so the current standings should be correct pending overnight updates. And Rhino16, tplbge, and I are history.

A very exciting race this year, especially compared to last season's wire-to-wire yawner. FYI, I merely need a two-part weather miracle to win (excluding any tiebreaker): (1) No more than 0.3 inches of additional snow at the three Baltimore-Washington area airports combined; and (2) In a best case (no more snow at any of those three airports), between 0. 7-1.3 inches of snow at RIC.

Okay. It appears that Clueless is now history, and Rhino16 and I are on life support.

The Capital Weather Gang is reporting that BWI has now picked up 2.6 inches in this storm. If that's the case, tplbge is the new leader with H20 second.

As my good buddy Joe Stalin liked to point out, the actual vote is not as important as who counts the vote. More seriously, I think the NWS does a good job of monitoring snow totals -- that's why adjustments are sometimes made after the fact.

A day like today in the Mid-Atlantic, where the temperature was above freezing the entirety of the snowstorm, presents a challenge for snow measurers. According to the National Weather Service: "While acknowledging there is no perfect way of measuring snowfall, the following best practice accommodates the observer while ensuring the best consistency. If the snow event ends well before the end of the 24-hour observing period make the 24-hour measurement at the end of the snow event, if possible. For example if the snow event ends at 1PM, make the snowfall measurement at that time." See https://www.weather.gov/media/coop/Snow_Measurement_Guidelines-2014.pdf However, even by the time the snow ended today, which was around 1 PM in my area, a lot had already melted. When I first observed the snow coming down hard around 9 AM, I thought I would have to shovel for about an hour after the storm ended. In reality, no shoveling at all was required.

This doesn't change the top of the leaderboard, but apparently RIC managed to get 0.1 today, to bring the seasonal total to 4.4.

I think Rhino16 is now a slight favorite, but MillvilleWx is eliminated. The latter has negative departures in three locations, and so can't pick up there. While he can pick up 1.8 on Clueless in Richmond, he trails by 3.1.

Right. The key is when someone already has a negative departure any additional snow increases that departure, whereas if someone has a positive departure any additional snow decreases that departure up to the point the departure is eliminated. So, for example, if Contestant A has a negative departure at all four locations whereas Contestant B has a positive departure of at least an inch at all four locations, a 1-inch snowfall at each location results in a loss for Contestant A of four points and a gain for Contestant B of four points -- an eight-point swing in Contestant B's favor.

You're correct about @RickinBaltimore and @biodhokie. The former trails by 2.6 and can pick up only 1.6 (if he gains the maximum at DCA), and the latter trails by 4.3 and can pick up only 2.2 (1.2 at BWI and 1.0 at DCA).

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ____ DEN _ PHX _ SEA -0.4 -0.3 -0.1 -1.9 0.8 1.6 -0.3 1.1 -0.4

Blame @PrinceFrederickWx. He asked about five-year DCA snow totals, which I had not previously tracked. By the way, the IAD 5-year minimum was set way back during the 1972-73 through 1976-77 snow seasons, at 58.6 inches. The last four years at IAD have totaled 48.6 inches, and so under 10 inches this year there will break the record.