Snow!

We had a little snow a couple of days ago and got more tonight — it actually seems to be sticking now. The upcoming forecast varies depending on what you want to believe. So, for the next few days, I’m going to track which of the various weather resources is most accurate.

To keep these forecasts comparable, I chose the my home airfield of KBFI. It’s just over 4 miles from downtown, fairly close to Puget Sound, and low elevation. Thus, no funny stuff. I will update the results the following morning and on Tuesday, we will see which one’s the most accurate.

Source	Tonight (1/1/2004)	Friday (1/2/2004)	Saturday (1/3/2004)	Sunday (1/4/2004)	Monday (1/5/2004)	Tuesday (1/6/2004)
Seattle Times	Showers 39/32	Mixed 39/32	Snow 38/31	Mostly cloudy 32/29	Partly sunny 35/19
		Revised 1/2:	Snow 35/20	Partly sunny 29/29	Partly sunny 35/19
			Revised 1/3:	Mostly sunny 29/16	Partly sunny 30/19
				Revised 1/4:	Mostly cloudy 30/25	Snow 37/26
The Weather Channel	Snow showers /25	Rain/show showers 38/32	Snow showers 38/18	Partly cloudy 29/29	Partly cloudy 35/19
		Revised 1/2:	Snow 35/20	Partly cloudy 28/15	Partly cloudy 28/19
			Revised 1/3:	Mostly sunny 29/16	Mostly cloudy 32/25
				Revised 1/4:	Mostly cloudy 31/25	Wintry mix 38/32
Seattle PI/KOMO TV 4	Rain, Cloudy and cold 40/30	Cloudy and cold 35/28	Snow 32/20	Cold with some sun 28/22	Cloudy and cold 32/22
		Revised 1/2:	Snow 30/20	Partly sunny 28/18	Chance of snow 30/26
			Revised 1/3:	Mostly sunny 26/16	Chance of snow 30/26
				Revised 1/4:	Mostly sunny 30/24	Snow and sleet 38/36
KIRO TV 7	Mixed snow/rain 38/33	Mixed snow/rain 38/32	Snow 35/30	Partly sunny 32/26	Mixed snow/rain 35/24
		Revised 1/2:	Snow 33/30	Partly sunny 29/20	Snow 33/24
			Revised 1/3:	Partly sunny 29/20	Snow 33/24
				Revised 1/4:	Snow Flurries 30/14	4-12″ Snow! 37/28
KING TV 5	Mostly cloudy 37/31	Mixed rain/snow 37/31	Snow 35/32	Sunny 35/28	Partly cloudy 36/26
		Revised 1/2:	Snow 33/30	Sunny 30/22	Snow 31/19
			Revised 1/3:	Mostly Sunny 33/27	Snow 45/20
				Revised 1/4:	Snow 32/28	Wet snow 41/28
KCPQ TV 13	Scattered rain/snow /31	Rain and snow 37/30	Morning snow 32/21	Mostly sunny 28/19	Mostly cloudy 32/23
		Revised 1/2:	Snow 29/21	Sunny 29/21	Snow late 30/22
			Revised 1/3:	Sunny 27/16	Snow late 32/28
				Revised 1/4:	Snow late 32/28	Snow then rain 42/38
AccuWeather	Snow or flurries /30	Rain or snow shower 36/29	Snow or flurries 34/19	Partly cloudy 29/20	Mostly cloudy 32/23
		Revised 1/2:	Morning snow 33/17	Partly sunny 29/15	Snow late 35/30
			Revised 1/3:	Mostly sunny 30/12	Snow, ice, rain 34/27
				Revised 1/4:	Sunny then snow late 29/23	Snow, sleet, rain 42/37
National Weather Service	Light rain or snow /31	Rain or snow showers 37/25	Partly cloudy 35/23	Mostly sunny 35/23	Partly cloudy 35/25	Gives ranges
		Revised 1/2:	Morning snow 33/17	Sunny 27/20	Snow late 33/28
			Revised 1/3:	Sunny 27/16	Snow late 30/25
				Revised 1/4:	Snow late 30/25	Snow then rain 38/43
Actual	Rain, Snow 41/33.1	Rain, Snow 39/30.9	Snow 37.9/26.6	Mostly sunny 30/19.4	Overcast 28.9/19.4
Winner	KIRO TV7	Seattle Times	Seattle Times	KIRO TV7	Seattle PI/KOMO TV4
Runner(s) up	KCPQ TV 13, NWS	Weather Channel, KIRO TV 7, KING TV 5	KIRO TV 7, KOMO TV 4	AccuWeather	KCPQ TV13, AccuWeather

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Update 1/2/2004: Congratulations to KIRO TV 7 for being the closest to the official reported conditions for last night. I’m kind of surprised, given that there wasn’t much forecasting left to do for last night’s weather, how much the forecasts for last night differed.

We had about 2″ of snow where I live, and my kids are conducting experiments with snowballs in the freezer and building snow blobs on the curb.

I forgot to mention earlier that the National Weather Service forecast is the most wishy washy, providing ranges like “Highs in the lower to mid 30s.”

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Update 1/3/2004: The Seattle Times edged out the pack, though there wasn’t that much discrepancy because of the broad forecast (“rain or snow”), thus temperature factored more than normal. Curiously, the Seattle Post-Intelligencer and KOMO TV 4 did not forecast snow for Thursday or today.

As an added dimension, I’ve recorded revised forecasts underneath the original (it’s the smaller font). The first one is from tonight (Friday) for the remaining days. I will add additional lines for Saturday and Sunday’s revisions to provide some visibility into tweaking. I think Susan Dennis said it best, “My guess is they did not buy their 8 balls at the same place.”

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Update 1/3/2004 @ 11:00 p.m.: I’ve updated the forecasts and will add the “actual” tomorrow morning as there may still be some cooling.
Update 1/4/2004 @ 8:58 a.m.: As everyone — except the initial NWS forecast — predicted, it snowed yesterday. The Seattle Times was the closest in actual temperature, thus they are our winner for Saturday. I noticed that all of the revised forecasts for Saturday were further off the actual temperature at the official site. For example, the Seattle Times was initially five degrees off the high/low ((38 – 37.9) + (31 – 26)), but revised their temperatures further down and were nine degrees off ((35 – 37.9) + (26 – 20)). For the record, I’m measuring the low during the 24 hour period ending at 23:59:59 local time.

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Update 1/4/2004 @ 8:50 p.m.: The forecasts for Tuesday are pretty interesting with one station going out on the line and calling for 4-12″ of snow and another hinting this could be as big as the ‘zard of 1996. I’ve added those to the table, but they won’t be included in the final results. (Or maybe they should, as they’re so vastly different ;-) Tonight’s winner will be updated later this evening.

Update 1/5/2004 @ 7:17 a.m.: Originally, everyone except the Seattle Times originally predicted a lot of sun. KIRO TV 7 and KING TV 5 were the closest to the actual temperatures. (KIRO edged out KING by 0.2 degrees, hence is today’s winner.) Looking at the revised forecasts, everyone except KING TV 4 got further off in temperature.
Today’s forecasts range from mostly sunny to snow. This will serve as a tie-breaker for the Seattle Times and KIRO TV 7.

Update 1/6/2004 @ 12:20 a.m.: Here’s a bizarre result… based on the original forecasts, Seattle PI/KOMO TV4 was the closest, however they revised it to mostly sunny, which is certainly wasn’t. KCPQ TV13 and AccuWeather were runners up with “mostly cloudy” and 6.7 degrees difference from actual.

KIRO TV7 is most accurate overall based on being closest two days and runner up two days. (Not weighted, but still worth noting is their original forecast for Monday was about six hours too aggressive. It will likely snow Tuesday morning, turning to rain sometime thereafter.)

Congratulations, KIRO TV7!