RodneyS

This year on January 13th DCA recorded a minimum of 28 and a maximum of 51 degrees, and on January 21st DCA recorded a minimum of 16 and a maximum of 24 degrees. Those temperatures continue the strong trend toward a lower average temperature on January 21st than on January 13th, and bring both the January 13th and 21st DCA average temperatures for the 12 years that I have now been tracking them (2014-2025) very close to the prior DCA 30-year averages (1984-2013) for those two calendar days. That, in turn, means that the differences at DCA in the January 13th and January 21st average temperatures for 2014-2025 and 1984-2013 are about the same during each period. Specifically, the average temperature at DCA during 2014-2025 for January 21st was 8.8 degrees lower than the average temperature for January 13th, whereas during 1984-2013 that lower difference was 8.2 degrees. That provides even stronger evidence that what I found in January 2013 was not merely an aberration from the first 112 years of daily temperature recordkeeping in DC (1872-1983) -- in which the average temperature was 3.5 degrees higher on January 21st than on January 13th -- but rather a fundamentally new, if currently unexplained, reality: Period Jan 13 Jan 21 Jan 21 minus Jan 13 1872-1983 33.3 36.8 +3.5 1984-2013 40.3 32.1 -8.2 2014-2025 41.3 32.5 -8.8 Note that@Rhino16and I have done some additional research that indicates that a similar January 13th to 21st temperature shift has occured in other Eastern locations in recent years -- see my post of February 20, 2020 and his post of February 28, 2024 above. Does anyone here have a hypothesis as to what is causing this shift or know of someone who is researching this issue?

A little more snow yesterday at BWI, DCA, and IAD, but none at RIC -- @psuhoffman is still on top, but now with negative departures at all four airports. So @87stormsis in good position to take the lead with just a tad more snow at BWI, DCA, or IAD, and plenty of contenders are lurking with positive departures at each of those airports.

Another 0.1 inch at DCA and 0.3 inches at IAD Thursday evening. No change to the top of the leaderboard, but minor changes further down, as we prepare for perhaps 1-3 inches more on Sunday.

Just as BWI was earlier upgraded to 1.8 inches for this storm and RIC was finalized at 3.0, IAD has now been upgraded to 2.6 inches, and so the 2024-25 seasonal total there is now 8.9. See below revised table, which does not change the leaderboard much:

Thanks. Perhaps the snow measuring crew at RIC is inexperienced, and is not following the guidelines set forth here, although snow measurement is as much of an art as it is a science: https://www.weather.gov/gsp/snow

Thanks. It looks a little odd for RIC to have received 3 inches of snow with only 0.20 inches of precipitation. That's a ratio of 15 to 1, whereas the previous night's listing was 1 inch of snow with 0.09 inches of precipitation -- a ratio of 11 to 1. Not that ratios can't vary that much during a storm, but the initial report today of only 2 inches of snow at RIC would translate into a ratio of 10 to 1. In any event, if the 3 inches holds, it won't change the top of the leaderboard much, with @psuhoffmanstill holding a clear lead.

Thanks -- here is a further update to reflect that change:

Thanks, I found that same storm total at https://forecast.weather.gov/product.php?site=AKQ&issuedby=AKQ&product=PNS&format=CI&version=1&glossary=1&highlight=on

I think I have found the amount for RIC, which is 3.0 inches. So, pending any further updates, it appears that @psuhoffmanhas taken the lead:

I have the following reported snowfall for the Friday-Saturday overnight storm: BWI: 0.5, DCA 0.7, IAD 1.8. Does anyone have the amount for RIC? Perhaps @RIC Airport?

I believe that 17 of our 69 entrants have now been eliminated from winning this season's contest.

Thanks. Not quite sure how the measuring gurus at RIC could have confused the revised 3.0 inches on Sunday and 0.5 inches on Monday with the originally reported 4.0 inches on Sunday and 2.0 inches on Monday, but life is full of mysteries. Here is the corrected summary table, which is excellent news for @StormyClearweather and @Mordecai, who were eliminated from contention under the originally-reported 6.0 inches at RIC, but are now the Top Two!

A larger than anticipated overnight snowfall has propelled psuhoffman into the lead. RickinBaltimore had a memorable reign, even if it lasted for only a few hours.

Big shake-up after today's numbers came in, with RickinBaltimore now the very tenuous leader -- tenuous because he has negative departures at each airport. Mordecai is in good position to take the lead if a little more snow is reported overnight, as his departures are all positive.

Thanks -- the below table further updates the current IAD total, which looks like will undergo a major update come Monday.

Today's brief squall added another 0.1 at Dulles.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH __ DEN _ PHX _ SEA -2.8 -0.9 -0.4 -0.8 -2.8 -0.2 0.9 0.6 -0.3

December 2024 at DCA averaged 41.9 degrees, 0.2 above the 1991-2020 normal and tied for the 32nd warmest December in DC history. The bigger news is that calendar year 2024 at DCA averaged 61.8 degrees, which broke the previous DC calendar year record high average of 61.6, which was set in 2012.

A Christmas Eve mini-ice storm today ruined LongRanger's bid for a perfect score, but he still maintains his lead.

You're welcome. This contest is always a lot of fun -- especially when you win, as you did five years ago.

See below summary table. We have 69 entrants this year, which is about halfway between two years ago (64 entrants) and last year (75 entrants). 52 of our 69 entrants this year played last year, and 17 either played two years or more ago or are new to the contest. The forecasts are generally lower this year. Specifically, here are this season's mean forecasts for each airport, with last year's mean forecasts in parentheses: BWI 14.1 (25.5), DCA 9.3 (18.4), IAD 16.0 (28.1), RIC 6.8 (13.5). The actual totals last year were: BWI 11.3, DCA 8.0, IAD 11.7, RIC 0.7. So this year's forecasts are in line with last year's actuals, with the exception of RIC, which presumably last year was an aberration for the second straight time.

November 2024 at DCA has for sure broken the record high average November DC temperature of 54.8 degrees, which was set in 2001. DCA finished at 55.2, which resulted in a record high January-November average of 63.6, beating the previous 11-month record of 63.1, which was set in 2012. That puts DCA on course to break the previous DC calendar year record of 61.6, also set in 2012. All that is needed is for DCA to average 39.0 degrees or higher in December -- 39.0 would be 2.7 degrees below the 1991-2020 normal. Note: Edited on December 1st because the final November 2024 DCA temperature average was 55.2, rather than 55.1

DCA _ NYC _ BOS __ ORD _ ATL _ IAH __ DEN _ PHX _ SEA -3.7 -3.2 -3.2 -2.5 -3.6 -1.5 2.9 2.6 1.1 DCA _ NYC _ BOS __ ORD _ DTW _ BuF __ DEN _ SEA _ BTV 5.8 22.0 38.5 42.5 45.0 99.0 58.0 9.5 85.0

Reminder: The deadline for this contest is fast approaching: Sunday, December 1, at 11:59 PM EST -- the contest will lock then, and no late entries will be permitted. So, if you have not entered thus far and wish to do so, follow my below example (except for using the same numbers) and do it now. BWI: 9.6" DCA: 5.8" IAD: 12.1" RIC: 6.1" Tiebreaker (SBY): 5.4"