Updraft: March 29, 2011 Archive

Big bad scary forecast models-not so scary today

Posted at 8:52 AM on March 29, 2011 by Paul Huttner
Filed under: Crow River, Flooding, Minnesota River, Mississippi River, Red River, Winter/spring 2011

It takes restraint to be a weatherman sometimes.

Last night was one of those times. Let's hope the restraint is justified in the long run...

Last night's 0Z (evening) GFS model run painted a really scary picture for a big Sunday rain storm, followed by several inches of heavy wet snow Monday. Today? We'll it would be too extreme to say "poof" it's gone, but not by much.

GFS: From 6"+ snowfall down to 1" in next 5 days.

The overnight (06Z) GFS run is brining things back to reality a bit. It still spins up a low pressure system Saturday night into Sunday, but does not create the "bomb" fantasized by the earlier model run.

More like .6" liquid instead of 2"+??

Talk about a sigh of relief. Whew...

GFS having a bad month:

I don't verify numerical weather forecast models for a living... (Believe it or not there are people at NOAA who do that!) but I do use them everyday. It seems to me that the GFS (the primary U.S. medium range forecast model) has been out to lunch lately.

Remember the "mega storm" about 2-3 weeks ago that lead to some alarming headlines of 1'+ snow totals...only to end up as 1" at MSP Airport? Thank the GFS.

To say we've been seeing a high degree of "variability" in the GFS solutions in the 3-10 day range would be putting it kindly. More like wildly inaccurate solutions...often brewing up monster storms that turn out to be highly overblown.

I can't say why this is happening for sure. But seasonal variations usually lead to model trouble. The models have trouble gauging the transitions during spring and fall.

I can tell you this, it's no fun to be a forecaster staring down the barrel of a (fictional?) 1' to 2" heavy rain followed by a 6"+ snow event in early April...and having to swallow hard and not publish it in hopes that the model was just going through some growing pains.

Let's hope today's runs confirm the idea that we will get some rain Saturday night and Sunday...but a more manageable amount under an inch in most locations...followed by a few wet, wind driven snowflakes Monday on the colder backside of the low.

Rivers dropping fast:

It's good to see river levels dropping fast west of the metro today.

The Crow is down around 1 foot in Delano since Sunday.

The Minnesota is down 1.5 feet in Mankato, and is now receding in Henderson.

Yay!

The Minnesota is cresting today in Jordan.

The Mississippi is forecast to crest tomorrow in St. Paul well below the earlier threats of a flood rivaling the 1965 fiasco.

Two crests better than one?

There's plenty of talk about a "double crest" of 2nd crest for many area rivers this spring. This may be a good thing.

Moving 80"+ of winter snow melt down the rivers in two separate (but lower) surges may be a better outcome than having one big "mega crest" that could produce a flood of record for many river locations. Most flood protection can better handle two moderately high crests then one big flood that could top dikes & levees.

The double crests expected this spring may be a godsend.

Red River trouble?

The one exception to this scenario may be the Red River of the North. The big thaw never really hit the Red, and there's still plenty of water in snow to melt when things warm up later this week into the weekend. The Red may see one big crest...and the latest forecasts still put the chances high for a record flood on the Red at Fargo and other river points.

All quiet on the Red...for now.

We'll watch as that story unfolds over the next two weeks.

Southern Minnesota river outlook better?

It still looks to this forecaster like we may be able to thread the needle on avoiding record flood levels for the next week at least, even with some hint of river rises next week due to melting and additional rainfall.

Let's hope so.

Stay tuned...

Signs of spring?

Yes, the forecast modles are hinting at more 40s & 50s the next two weeks. But this guy really caught my eye this morning. A sure sign of spring?

Big fat robin sunning outside weather lab window Tuesday morning.

There's hope!

PH