Weather gurus out there-

**matmann22** · 02-11-2009, 01:43 PM

Originally Posted by 4VR4CY

Nope. Des Moines on Friday.

Over the lunch hour ?

I would guess the worst of it will be midafternoon or evening in Des Moines. You may have an inch or so of snow by the time the lunch is over...

Going home to the North is a much better idea than going South or West afterwards.

**cstrunk** · 02-11-2009, 01:51 PM

Well, it's still two days away so there is a lot that can and will change between now and then. Based on what I've heard, 6" from Ames to southern Iowa is a good possibility. I would go with 4-8" if I had to give a forecast right now. Could see less depending on how moisture and storm track end up... could see more also with the possibility of thundersnow!

**matmann22** · 02-11-2009, 01:54 PM

Originally Posted by kingcy

It will be a big storm. They were calling for a little bit of snow earlier in the week and now they are increasing it. When they do that it means a big one is coming.

This has been a big storm since at least the early Monday model runs of the Euro model (the best long term model lately, unlike the GFS (sometimes called the Good For S***t) model.

Weather forecasters try to hedge their positions a little given how fickle computer models can be. They put some type of snow in there 4 or 5 days out as a CYA. Then as the event gets closer they get a little more specific or slowly take it out.

Another reason they hedge their bets like this is that Friday's storm is still not (or barely) in the continental US weather sensor network. This means the models are running off of slightly imperfect information from the start.

Too many distant storms would dissappear and reappear if every computer model run were put in the forecast. The 18Z GFS model is known for its particularly bizare behavior. For humor sake, go to Accuweather and look at the 15 day forecast and keep track of some of the wild changes. This forecast is the 15 day GFS model with little or no human adjustment so it will be too cold(among other things) in the long term.

A great example of forecast hedging was that big cool down for last Wednesday. The Des Moines National weather service office on Monday morning wanted to go much colder than the computer model forecast which was 15F for Wednesday. After coordinating their forecast with the surronding offices and considering the existing forecast for Wednesday, they stayed at 15F. The high that day I believe was 21F. The public learns these things by reading the online forecast discussions...

**Wesley** · 02-11-2009, 01:59 PM

3-6 in Omaha.

**Incyte** · 02-11-2009, 02:00 PM

My wife and I leave DSM friday at 4:30 for Dublin, Ireland. If our plane does not take off, I will go straight to Channel 13 headquarters and kick Ed Wilson in the pearls.

**FDWxMan** · 02-11-2009, 02:03 PM

Originally Posted by matmann22

This forecast is the 15 day GFS model with little or no human adjustment so it will be too cold(among other things) in the long term.

Model fantasy land!...as it's called inside good ol' Agronomy at ISU.

**jdoggivjc** · 02-11-2009, 02:04 PM

Originally Posted by kingcy

It will be a big storm. They were calling for a little bit of snow earlier in the week and now they are increasing it. When they do that it means a big one is coming.

Yeah, I remember in these parts where a snow forecast increased from very little to a foot plus. We didn't see a single snowflake that evening...

**jdoggivjc** · 02-11-2009, 02:04 PM

Originally Posted by kingcy

It will be a big storm. They were calling for a little bit of snow earlier in the week and now they are increasing it. When they do that it means a big one is coming.

Yeah, I remember in these parts where a snow forecast increased from very little to a foot plus overnight. We didn't see a single snowflake that evening...

**d4nim4l** · 02-11-2009, 02:23 PM

Originally Posted by matmann22

This has been a big storm since at least the early Monday model runs of the Euro model (the best long term model lately, unlike the GFS (sometimes called the Good For S***t) model.

Weather forecasters try to hedge their positions a little given how fickle computer models can be. They put some type of snow in there 4 or 5 days out as a CYA. Then as the event gets closer they get a little more specific or slowly take it out.

Another reason they hedge their bets like this is that Friday's storm is still not (or barely) in the continental US weather sensor network. This means the models are running off of slightly imperfect information from the start.

Too many distant storms would dissappear and reappear if every computer model run were put in the forecast. The 18Z GFS model is known for its particularly bizare behavior. For humor sake, go to Accuweather and look at the 15 day forecast and keep track of some of the wild changes. This forecast is the 15 day GFS model with little or no human adjustment so it will be too cold(among other things) in the long term.

A great example of forecast hedging was that big cool down for last Wednesday. The Des Moines National weather service office on Monday morning wanted to go much colder than the computer model forecast which was 15F for Wednesday. After coordinating their forecast with the surronding offices and considering the existing forecast for Wednesday, they stayed at 15F. The high that day I believe was 21F. The public learns these things by reading the online forecast discussions...

This is actually one of my favorite things to do. Especially during hurricane season.

**d4nim4l** · 02-11-2009, 02:25 PM

For those of you who wonder what he is talking about:

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
538 AM CST WED FEB 11 2009

IAZ033>039-044>050-057>062-070>075-081>086-092>097-121200-
SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-
CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-
POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-
ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-
WAYNE-APPANOOSE-DAVIS-
538 AM CST WED FEB 11 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

FLOOD WARNINGS ARE IN EFFECT FOR PARTS OF THE AREA. PLEASE REFER
TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

SNOW WILL SPREAD INTO THE AREA FRIDAY AND CONTINUE FRIDAY NIGHT.
HEAVY SNOWFALL IS POSSIBLE FOR PARTS OF THE AREA...ESPECIALLY
SOUTH OF U.S. HIGHWAY 30...WITH ACCUMULATIONS OF 6 INCHES OR MORE.
THERE IS A POSSIBILITY OF THUNDER WITH THE SNOW FRIDAY AFTERNOON
AND EVENING...WHICH COULD LEAD TO LOCAL HEAVIER SNOW ACCUMULATIONS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

$$

**FDWxMan** · 02-11-2009, 02:28 PM

Well, that's a good start for any upcoming major weather. If you want the real nuts and bolts of their actual discussion of the forecast, check this:

National Weather Service Text Product Display

This has bunch of abbreviations in it though, so good luck if you aren't familiar with the NWS jargon.

**CO4Cy** · 02-11-2009, 02:47 PM

Now on to more important things.....is gurus a word?

**d4nim4l** · 02-11-2009, 03:14 PM

Originally Posted by FDWxMan

Well, that's a good start for any upcoming major weather. If you want the real nuts and bolts of their actual discussion of the forecast, check this:

National Weather Service Text Product Display

This has bunch of abbreviations in it though, so good luck if you aren't familiar with the NWS jargon.

Even better. Thanks.

I learned some of the jargon the unpleasant way in 2005. Tracking Hurricane Rita while I was in Houston...

**FDWxMan** · 02-11-2009, 04:41 PM

Originally Posted by d4nim4l

Even better. Thanks.

I learned some of the jargon the unpleasant way in 2005. Tracking Hurricane Rita while I was in Houston...

Oh man. Not fun.

I was in Florida for Charley in 2004, though I was in Cocoa Beach, on the other of the peninsula from landfall so it wasn't terrible. Still tropical storm force winds though.