If you're like most people, you like to start thinking about your next summer weekend just about the time the current weekend winds down (at least that's how we like to think!). That's the approach we took on Sunday, July 16. That evening, we gathered the temperature forecasts for the ensuing weekend (July 23-24) and plotted them on our handy Excel spreadsheet as follows (note: KARE11 does not formally forecast beyond five days, but Sven Sundgaard suggested that "90s were quite possible for the weekend"):
We thought that this forecast had a fair amount of challenge because there was a major heat wave that was about to hit high gear early in the week for a somewhat uncertain duration. The following table summarizes the forecast error for each of the weather oulets (we arbitrarily used 92 as the predicted temperature for Saturday and Sunday for KARE).
Amazingly, Weather.com (The Weather Channel) was exactly right for both days' forecasts. Based on our analysis, the rank order of all outlets was:
#8: Star Tribune
There's not all that much to take from this. It is, after all, just a one-weekend extended forecast sample. Were we do to this for every weekend over the course of a longer time -- months to a year -- the results would be a lot more meaningful. Also, and just as importantly, we didn't record the forecast as it related to sky conditions/storms, etc.
Still waiting for that below average summer I was told was coming. Can't wait for August as this July was nothing but above average. Any days at all below average high this month?ReplyDelete
Big MCS poised to come in from the Dakotas...ReplyDelete
wonder when it will get here.
I don't exactly remember the CPC forecast, but I'm betting it was something like a 40% chance of a below normal summer which is more then the 33% equal chance.ReplyDelete
Meteorological summer is only half over. We could see a record cold August and it would all even out to normal or below. In the meantime, if our meteorologists can't get a forecast right 24-48 hours out, how are they supposed to forecast an entire season?ReplyDelete
Ok Bill, time for a new thread, I know it's late but I had to see this. All of the global models including the GFS, the ECMWF and the Nam (which is not a global model, but still includes the Gulf) have initialized very poorly, none of them see the current observed 1000mb low just NW of the Yucatan Peninsula that shows where Don is. How will this system effect our weather? We could get more upper moisture in this area..any forecast that is published by are local mets need's to be taken with a large dose of salt lolReplyDelete
so my next thread would say something like this....How will Don affect our forecast????...as matter of fact that's how I would word it.
It's time our mets earn their pay instead of looking at moss guidance and spiting it outReplyDelete
With the ridge locked in place over the southern plains I would expect the remnant of Don to move NW thru texas and then come up the rocky mountains. I would expect a good chance of Don's moisture affecting at least some part of the upper midwest/northern plains.ReplyDelete
About CPC forecasts...ReplyDelete
They are climate outlooks issued as probabilities of temperatures/precipitation to *deviate from climatology* for a three month period based on terciles. Climatologically, there is a 33% chance of temperatures/precipitation being below, near, or above normal. An outlook that deviates from that will detract first from the opposite extreme (to a minimum of 3%), then the middle tercile. For example, an outlook for June-July-August of 60% probability for below normal temperatures means 60% chance of the *average temperature during June-July-August* being in the lowest tercile, 33% chance of it being in the middle tercile, and a 7% chance of it being in the upper tercile.
As for Don's moisture...
the system is rather small and by the time that moisture arrives in MN it'll be quite high in the atmosphere and not do much for rain chances. The initialization of the central pressure isn't a massive "miss" for the models as the storm as about to make landfall and will be quickly decreasing in intensity at that point.
When the guys at the National Hurricane Center can't believe what they see, you know something crazy happened.ReplyDelete
POST-TROPICAL CYCLONE DON DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042011
400 AM CDT SAT JUL 30 2011
THE DON IS DEAD. THE CYCLONE LITERALLY EVAPORATED OVER TEXAS ABOUT
AS FAST AS I HAVE EVER SEEN WITHOUT MOUNTAINS INVOLVED. DON HAS NO
CONVECTION...MEAGER RAINFALL...AND ONLY A SLIGHT SIGNATURE IN
SURFACE OBSERVATIONS AND RADAR DATA. THEREFORE...THIS IS THE LAST
ADVISORY ON THIS SYSTEM.
Another busted forecast...didn't check anyone else this morning but @morningwxguy was particularly cocky this morning before his forecast fell flat on its face.ReplyDelete
When I went to bed last night, they had isolated t-storms for today at a 30% chance. This is a 100% washout. The rain won't move out of the metro until 4-5 pm at the earliest. Cloudy all day. No way we hit 90, though for that, I'm grateful.ReplyDelete
I wish you would compare the forecasts to what really happens every weekend and post the results. I'd really like to see this.ReplyDelete
Summer forecasts seem challenging to critique in two respects:ReplyDelete
1) There are not often clear differences ... like when one forecasters says there will be storms and another says it will be dry
2) For consistent temperature regimes like we've seen, there's little to differentiate forecasters
Finally, in a situation like today's, EVERYONE had a bust as far as I know. And actually, this happens a lot as they're all going off the same information.
What exactly would you like to see compared for weekend forecasts? Specifically, using the forecast from which day?
Can anyone recall another summer with these huge rain spikes? I can't. I've been impressed with this series of storms producing torrential rainfall.ReplyDelete
Here's another stupid question. All this rain is keeping the ground wet. So when the water evaporates it unleashes more water into the air...leading to another deluge...and the cycle continues. Or am I way off base?
This has certainly been one of the most humid summers on record, hence the extremely warm low temperature average in July. It's ridiculous. I would give anything for an 80 degree day with no humidity. Anything.ReplyDelete
I checked the NWS around 7 AM and they showed a 20% chance of rain where I live (Shakopee). Then I looked at the radar and estimated a 100% chance of rain. Do they ever leave their computer models and just look at the storms that are moving around?ReplyDelete
Today was really one of the better busts for a while.
Just added a fresh post to discuss today's busted forecast.ReplyDelete