The Utility of Winter Storm Forecasts

[Mike Smith]

Earlier this morning, I posted a comment in the winter weather NOW thread that we are being awfully hard on ourselves if we think a forecast of 4-6" of snow is a "bust" when 2-3" actually fell. My original comment is at http://stormtrack.org/forum/showthread.php?p=255398#post255398 .

Rather than hijack that thread, I have started a new one to elaborate on my perspective about the forecast in question.

Lets look at the elements of the forecast in question.

Cloudy was forecast. Was it cloudy? Yes.
"Measurable" snow was forecast. Did 0.01" or more of (liquid) snow fall? Yes.
Four to six inches forecast. Did 4-6" fall? No, 2-3" fell.
High winds were forecast, did they occur? Yes, peak gust 44 mph.
Extreme cold was forecast, did it occur? Yes, current wind chill in LNK -22°

This forecast hardly looks like a "bust" to me. We informed the public of a dangerous cold wave with snow that would blow and make travel difficult. The essence of the forecast came true.

Why am I pointing this out? Because it seems we in the meteorological profession often seem to be unable to articulate the considerable progress we have made in the fields of storm warnings and forecasting. Twenty years ago the snide remark, "I just shoveled six inches of 'partly cloudy' off my driveway" had more validity than we would have liked. It rarely is valid now.

Does not mean we should stop striving to improve? Of course not. But, when we have situation where the snow/water ratio is very difficult (as it is in this situation) we should be better at articulating what went right as well as what went wrong.

 

[John Vandehei]

You do raise a valid argument. From a meteorological standpoint, the forecast looked good according to the conditions and parameters you stated. However, the amount of snowfall is the standard benchmark that the majority of the public uses when gauging a winter storm event. Even though two inches of dry wind whipped snow can cause more travel problems than four inches of snow with no wind, the general public will generally consider the seriousness of the event to be proportional to the amount of snowfall. Because of this, forecasters put a lot on importance in trying to forecast snowfall amounts.

 

[Mike Kovalchick]

Part of the problem of NWS Winter Forecasts is a disconnect between what the forecastor knows and what actually goes out in the standard public forecast.

Reading an area forecast dicussion(which generally really shows what the forecaster is thinking and expects) and then comparing it to the forecast product, it is amazing how much is lost in translation.

I also agree that the public's measure of success...the actual inches of snow that fell on the sidewalk in the front of their house..it exceptionally difficult to nail down what with the variability of snowfall over a small area and all the issues related to determining how much snow will fall with a given QPF.

It is interesting to note that forecast models as a rule perform better in the Winter than the Summer but I suspect if you asked the public..they would say Winter forecast's are more prone to bust.

 

[David Goines]

I was actually wanting to have a discussion about this on here. So thanks for starting one.
Down here (around Ft. Smith, AR) the NWS and local news stations were all saying "a dusting to one inch in the Ft Smith area and 1-2 inches in NW Ark" and winter storm advisories were issued all over the area.
Well, morning comes, and there's not a single snowflake to be seen and the roads/bridges are dry as a bone.
I have never seen so many facebook statuses about how wrong the meteorologist are and how they never get anything right. I wanted to just punch them all in the face and show them how complicated winter storms are when forecasting for them. It's annoying how the general public thinks "weathermen" should be able to give pinpoint forecasts down to street level and get it right every time.
Like you said Mike, there's plenty of room for improvement with forecasting but come on, if the forecast says "60% chance of snow with accumulations less than one inch".
Don't be griping at the meteorologists if no snow falls!
Ok, off of my soap box now....

 

[Mike Smith]

I have two comments...

#1. I just learned that the westbound and eastbound Amtrak California Zephyr's are both stuck just west of Lincoln (due to the trains being so late their crews expired due to 'hours of service law'). Since Lincoln's forecast was the basis for this thread, it appears that conditions were sufficiently severe that railroad transportation was affected. This, to me, adds weight to my contention that the forecast, while not perfect, was not a "bust." Separately, Amtrak's Texas Eagle is currently stuck between St. Louis and Springfield, IL.

#2.

I have never seen so many facebook statuses about how wrong the meteorologist are and how they never get anything right. I wanted to just punch them all in the face and show them how complicated winter storms are when forecasting for them. It's annoying how the general public thinks "weathermen" should be able to give pinpoint forecasts down to street level and get it right every time.

I worry that this will come across as self-serving, but here goes... That is exactly why I have written my book. Meteorology has been more successful, during the last 50 years, at saving lives when compared to cardiology, cancer research or traffic safety -- at a tiny fraction of the cost. It is time we got some of the respect our profession deserves. If you would like to see the cover of the book or read more, it is here: http://www.amazon.com/Warnings-Stor...=sr_1_1?ie=UTF8&s=books&qid=1261771583&sr=1-1

I bring this up because within the hour I've learned that a child of a friend of mine's cancer has returned in aggressive status -- after the child was thought to be "cured." It is a tragedy for all concerned. But, doctors don't seem to get the Facebook posts and sarcasm directed toward our field. So, cross your fingers that the book is successful and please offer your prayers for my friend's child.

 

[MatthewCarman]

The NWS was right in their forecast for my area. There is over 4" of new snow on the ground and they forecasted 4-9" for my area. I do know things do not always turn out as expected. With the last big storm I was expecting alot of snow and ended up getting rain for the first day because the front/low moved east slower than expected leaving me in the warm sector while 5-10 miles west it was all snow. I don't think we can blame the NWS for that. We can't expect them to get it right every time. I know people who get annoyed when the NWS or local TV station get's the forecast wrong. I would like to see them try and do better.

 

[Robert Dewey]

I also think people tend to look at "worst case scenario" when they see a forecast. If the forecast calls for 8-12 inches, and you get 7 inches... that's only an error of one inch, but I think many would see it as "they said we were going to get 12 inches, and we only got 7!"

 

[Larry J. Kosch]

Variable Factor in Forecasting

Lately I've noticed both the NWS and the local weather forecasts have been dealing with the "Variable Factor" in forecasting winter weather.

Most of the snow forecasts have been "on the money" in terms of forecasting snow, wind and colder weather. Some forecasts have been off in terms of predicted snowfall amounts, compared to actual snowfall reports. Some reports were within +-5 degrees of forecast low/high temps.

I watch the Weather Channel all the time (not during bowl season! ) and base my planned activites for the day on the weather forecasts. Is it going to be bitterly cold? I will wear my heavy red/black parka coat. Is it going to be above freezing? Plan on some sloppy winter driving thru slushy snow. Will it snow all night or end today? I get my snowblower out when I get home from work.

While I think the weather forecasting technologies have made great strides, I think the general public needs to be better educated when it comes to dealing with weather forecasts. It should be more than "how many inches will I have on my sidewalk?"

 

[Dan Robinson]

It seems like specific snow totals are more psychological and a less relevant issue in reality. In most areas, from 2 inches to about a foot, impacts are the same - schools close, people will have to go out and shovel, call in snow removal contractors, etc. 2 inches of snow vs 6" or 12" isn't all that different in terms of societal effects. Above a foot, the impacts in that range are not all that different either, since 14"-18" or more will start making snow removal and mobility more difficult. If you get 14" you might as well get 22".

When I had a foot at my house last month, it really wasn't a big deal as far as the time it took to shovel and salt my sidewalk. At least compared to 2, 3 or even 4 inch events. A little more weight per shovel swipe, but that's it. City plows had things clear in about the same amount of time as they normally do.

In other words, if a forecast calls for 3 inches and you get 10, it doesn't change much as far as what people have to do to deal with it. It's more in people's heads as to how much the exact numbers matter.

 

[rdale]

The NWS was right in their forecast for my area. There is over 4" of new snow on the ground and they forecasted 4-9" for my area.

4 - 9 inches? Are you sure that was their forecast? If so - that's pretty useless. 4 inches is a bit of a nuisance. 9 inches is a major event.

I suppose it's safer to forecast "2 to 12 inches" if you want a perfect forecast, but does that offer value?

 

[Rob Wadsworth]

The PSYCHOLOGY behind the Winter storm...

The NWS aren't infallable - but they are most often correct.
Conservative forecasts are their bread and butter...

Here is an old chestnut below.
Maybe you have all seen this already - maybe not.
We might laugh because it is funny.
But even funny must take its roots from irony - consider this too.
Based upon what others have posted; I thought some light humor may bode well...Enjoy
----------------------------

DIARY OF A SNOW SHOVELER
December 8 - 6:00 PM
It started to snow. The first snow of the season and the wife and I took our cocktails and sat for hours by the window watching the huge soft flakes drift down from heaven. It looked like a Grandma Moses Print. So romantic we felt like newlyweds again. I love snow!
December 9
We woke to a beautiful blanket of crystal white snow covering every inch of the landscape. What a fantastic sight! Can there be a more lovely place in the whole world? Moving here was the best idea I've ever had! Shovelled for the first time in years and felt like a boy again. I did both our driveway and the sidewalks. This afternoon the snowplough came along and covered up the sidewalks and closed in the driveway, so I got to shovel again. What a perfect life!
December 12
The sun has melted all our lovely snow.. Such a disappointment! My neighbour tells me not to worry- we'll definitely have a white Christmas. No snow on Christmas would be awful! Bob says we'll have so much snow by the end of winter, that I'll never want to see snow again. I don't think that's possible. Bob is such a nice man, I'm glad he's our neighbour.
December 14
Snow, lovely snow! 8 inches last night. The temperature dropped to -20. The cold makes everything sparkle so. The wind took my breath away, but I warmed up by shovelling the driveway and sidewalks. This is the life! The snowplough came back this afternoon and buried everything again I didn't realize I would have to do quite this much shovelling, but I'll certainly get back in shape this way. I wish I wouldn't huff and puff so.
December 15
20 inches forecast. Sold my van and bought a 4x4 Blazer. Bought snow tires for the wife's car and 2 extra shovels. Stocked the freezer. The wife wants a wood stove in case the electricity goes out. I think that's silly. We aren't in Alaska , after all.
December 16
Ice storm this morning. Fell on my ass on the ice in the driveway putting down salt. Hurt like hell. The wife laughed for an hour, which I think was very cruel.
December 17
Still way below freezing. Roads are too icy to go anywhere. Electricity was off for 5 hours. I had to pile the blankets on to stay warm. Nothing to do but stare at the wife and try not to irritate her. Guess I should've bought a wood stove, but won't admit it to her. God I hate it when she's right. I can't believe I'm freezing to death in my own living room.
December 20
Electricity's back on, but had another 14 inches of the damn stuff last night More shovelling! Took all day. The dam snowplough came by twice. Tried to find a neighbour kid to shovel, but they said they're too busy playing hockey. I think they're lying. Called the only hardware store around to see about buying a snow blower and they're out. Might have another shipment in March. I think they're lying. Bob says I have to shovel or the city will have it done and bill me. I think he's lying.
December 22
Bob was right about a white Christmas because 13 more inches of the white crap fell today, and it's so cold, it probably won't melt till August. Took me 45 minutes to get all dressed up to go out to shovel and then I had to pee. By the time I got undressed, peed and dressed again, I was too tired to shovel. Tried to hire Bob who has a plough on his truck for the rest of the winter, but he says he's too busy. I think the butthole is lying.
December 23
Only 2 inches of snow today. And it warmed up to 0. The wife wanted me to decorate the front of the house this morning. What is she, nuts?!! Why didn't she tell me to do that a month ago? She says she did but I think she's lying.
December 24
6 inches - Snow packed so hard by snowplough, I broke the shovel. Thought I was having a heart attack. If I ever catch the son of a bitch who drives that snow plough, I'll drag him through the snow by his balls and beat him to death with my broken shovel. I know he hides around the corner and waits for me to finish shovelling and then he comes down the street at a 100 miles an hour and throws snow all over where I've just been! Tonight the wife wanted me to sing Christmas carols with her and open our presents, but I was too busy watching for the damn snowplough.
December 25
Merry fricking Christmas! 20 more inches of the damn slop tonight - Snowed in. The idea of shovelling makes my blood boil. God, I hate the snow! Then the snowplough driver came by asking for a donation and I hit him over the head with my shovel. The wife says I have a bad attitude. I think she's a fricking idiot. If I have to watch "It's A Wonderful Life" one more time, I'm going to stuff her into the microwave.
December 26
Still snowed in. Why the hell did I ever move here? It was all HER idea. She's really getting on my nerves.
December 27
Temperature dropped to -30 and the pipes froze; plumber came after 14 hours of waiting for him, he only charged me $1,400 to replace all my pipes.
December 28
Warmed up to above -20. Still snowed in. My WIFE is driving me crazy!!!
December 29
10 more inches. Bob says I have to shovel the roof or it could cave in. That's the silliest thing I ever heard. How dumb does he think I am?
December 30
Roof caved in. I beat up the snow plough driver, and now he is suing me for a million dollars, not only the beating I gave him, but also for trying to shove the broken snow shovel up his BUTT. The wife went home to her mother. Nine more inches predicted.
December 31
I set fire to what's left of the house. No more shovelling.
January 8
Feel so good. I just love those little white pills they keep giving me. Why am I tied to the bed?

 

[Jeff Duda]

4 - 9 inches? Are you sure that was their forecast? If so - that's pretty useless. 4 inches is a bit of a nuisance. 9 inches is a major event.

I can confirm that's what DMX was forecasting over their CWA.

 

[rdale]

Conservative forecasts are their bread and butter...

Not the offices I deal with... VERY rarely do they come in with forecasts less than what actually occurs.

I can confirm that's what DMX was forecasting over their CWA.

That's one thing - but if they forecast that for a particular point in their DMA then that's another.

 

[Greg Stumpf]

Perhaps if the winter forecast information was given as a distribution of values and their expected probability of occurrence, then we might get more insight into the forecaster's thought process, and allow users make more informed preparedness decisions. Giving a determinstic forecast (e.g., 3-4") that verifies out side that range may seem as a bust to some. But a probabilistic forecast showing the range of forecast values and associate probabilities could be much more useful (e.g., 0-1" 10%, 1-2" 20%, 2-3" 30%, 3-4" 40%, 4-5" 30%, 5-6" 20%, and so on).

As far as impacts, snow amount isn't the only factor. We just got through a blizzard that dumped what some might consider a meager 7" of snow on Norman, but combined with the wind and low temperatures, was allowed to drift (and re-drift after clearing) to 2-3' over roads in spots. That same 7" without wind probably would have been a lot more manageable from a road maintenance standpoint and a much lesser impact to local transportation. One much also consider the temperature of the road surfaces and other variables when assessing impacts.

 

[Mike Smith]

Perhaps if the winter forecast information was given as a distribution of values and their expected probability of occurrence, then we might get more insight into the forecaster's thought process, and allow users make more informed preparedness decisions. Giving a determinstic forecast (e.g., 3-4") that verifies out side that range may seem as a bust to some. But a probabilistic forecast showing the range of forecast values and associate probabilities could be much more useful (e.g., 0-1" 10%, 1-2" 20%, 2-3" 30%, 3-4" 40%, 4-5" 30%, 5-6" 20%, and so on).

Private sector meteorologists already do this for their clients.

This type of forecast is unlikely to be adopted by radio and television as it is too difficult for the general public to understand. Imagine listening to this list of numbers on the radio.