Here’s an animation that makes the point.

 Climate, Models, Northern Arizona Weather, Outlooks  Comments Off on Here’s an animation that makes the point.
Feb 162017
 
Animation of total precipiation from 4 different computer models runs for the same storm. (From Tropical Tidbits)

The computer GFS computer model is all over the place. Here is an animation of 4 images. All 4 images report total project precipitation through next Tuesday evening. Notice, it hasn’t started to rain or snow at this time, so that the start time doesn’t matter. The precipitation amounts are widely different. It looks like Flagstaff is in the 0.5 to 3 inches range, depending on which run you like.

The current Navy model, which doesn’t automatically calculate totals from more than 6 hours, appears to forecast a couple inches of precipitation. Currently, the GFS model has predicted more snowfall than earlier this week.

Animation of total precipiation from 4 different computer models runs for the same storm. (From Tropical Tidbits)

Animation of total precipiation from 4 different computer models runs for the same storm. (From Tropical Tidbits)

 Posted by at 11:33 am

Wetter ab dem Wochenende: Die Wettermodelle sind sich überhaupt nicht einig

 Models, Northern Arizona Weather, Winter Storms  Comments Off on Wetter ab dem Wochenende: Die Wettermodelle sind sich überhaupt nicht einig
Feb 152017
 

Reader: Stu, that title is in German.

Stu: I know, but it will make sense later on.

Bis Freitag scheinen sich die Wettermodelle noch sehr einig zu sein, was am Wetterhimmel passiert. Aber schon am Wochenende sind sie sich schon nicht mehr einig, die Temperaturspanne wird breiter. Und in der nächsten Woche liegen die Prognosen derzeit sogar 20 Grad auseinander. Das Wetter weiß noch nicht, wohin die Reise geht. Winter oder Frühling? Beides ist noch möglich. (wetter.de)

The computer models have been crazy with changes lately. As I read this brief story yesterday on wetter.de, it appeared very relevant to me. The computer models for the Southwestern US have been subjects to wild swings when predicting precipitation for the rest of the month, let alone this weekend.  According to this brief article, there is a 20 degree C difference between computer model runs. That means it could be sunny and 68 degree F on Saturday, or it could be freezing. I’m hoping for warm, and we are heading to Bamberg to test drive smoked beer.

This weekend will be wet, and the rain and possible snow will continue through Tuesday. Snow levels will start high, but drop through this time. Snowbowl should get a nice recharge. Somewhere between 1 and 2 inches of precipitation will probably fall between now and the middle of next week.

If you go to Google translate, you can copy and past the German text above and get a rough translation.

 Posted by at 11:17 pm

Rest of February looks wetter than on Friday

 Models, Northern Arizona Weather, Outlooks  Comments Off on Rest of February looks wetter than on Friday
Feb 122017
 
Total precipitation forecast from the GFS model through Sunday afternoon, February 26. (from TropicalTidbits.com on Sunday February 12, 2017))

The computer GFS computer model has been changing the precipitation outlook for the rest of the month quite a bit between runs. On Friday, the rest of the month, through Sunday evening, February 26, looked fairly wet. This image is reposted below.Flagstaff was in the 1.5 to 2 inch range.

Total precipitation forecast through Sunday evening February 26, 2017 from the GFS model. (from TropicalTidbits.com on February 10, 2017)

Total precipitation forecast through Sunday evening February 26, 2017 from the GFS model. (from TropicalTidbits.com on February 10, 2017)

This Sunday morning, everything looks remarkably wetter!!! Flagstaff is in the 3-4 inch, if not more, range. The series of storms for the rest of the month, including the current one, are proving very tricky for the model. Similar effects are showing up in the navy model. Still, the snow levels are projected to remain high for a while. A little snow could fall on Wednesday, and next weekend.

Total precipitation forecast from the GFS model through Sunday afternoon, February 26. (from TropicalTidbits.com on Sunday February 12, 2017))

Total precipitation forecast from the GFS model through Sunday afternoon, February 26. (from TropicalTidbits.com on Sunday February 12, 2017))

 Posted by at 8:22 am

Chance for heavy snow on Saturday night.

 Models, Northern Arizona Weather, Winter Storms  Comments Off on Chance for heavy snow on Saturday night.
Jan 122017
 
24 hour snowfall ending Sunday morning, January 15, 2007. (from Tropical Tidbits)

The next few days will bring precipitation now and then to the area, while temperatures remain warm. But, this current version of the 24 hour snowfall computer model shows that heavy snow could fall on Saturday night. Notice the small area of pink, white and green on the image below. Some locations, particularly at higher elevations, may receive over a foot.

The following weekend is still looking very snowy.

24 hour snowfall ending Sunday morning, January 15, 2007. (from Tropical Tidbits)

24 hour snowfall ending Sunday morning, January 15, 2007. (from Tropical Tidbits)

 Posted by at 10:53 pm

Will Flagstaff escape the next round of severe cold?

 Models, Northern Arizona Weather  Comments Off on Will Flagstaff escape the next round of severe cold?
Dec 302016
 
6-10 day temperature anomaly outlook from the Climate Prediction Center.

Snow is still on the way for the weekend, but the new question is how cold will Flagstaff be with next punishing cold wave. Current forecasts don’t look too bad. Temperatures in the low 30s for highs, and single digits for lows. But look at the outlook for the rest of the country!

6-10 day temperature anomaly outlook from the Climate Prediction Center.

6-10 day temperature anomaly outlook from the Climate Prediction Center.

The deeper shades of blue are not directly linked to lower temperatures, but the likelihood of below average temperatures. Most of Arizona will be 4-10 degrees below normal a week from today. Other parts of the West will be more than 20 degrees below normal.

Temperature anomaly for Friday night, January 6, 2017, from the GFS model at Tropical Tidbits.

Temperature anomaly for Friday night, January 6, 2017, from the GFS model at Tropical Tidbits.

 Posted by at 6:14 am

Another complex forecast – New Year’s?

 Models, Northern Arizona Weather, Winter Storms  Comments Off on Another complex forecast – New Year’s?
Dec 272016
 
6-10 day precipitation anomaly outlook from the Climate Prediction Center, December 26, 2016.

The Navy NoGaps or NAVGEM model isn’t matching the GFS model again. But this time, it’s the other way around. The Navy model from this morning so a dry spell ahead with no repeat of last weekend. The GFS model shows a pair of major storms hitting Arizona again. The one-two punch of last week could still be repeated this weekend.

Rain and/or snow are in the forecast for Thursday through Monday. Travel could be difficult for the entire holiday weekend. The GFS model shows heavy snow hitting Sunday. Currently, the Climate Prediction Center outlooks call for above average precipitation for the next two weeks. The 6-10 day precipitation outlook is below.

Since Tuesday is the first day of this work week, we will see how things change by the end of the day today. December is already way above average for precipitation.

6-10 day precipitation anomaly outlook from the Climate Prediction Center, December 26, 2016.

6-10 day precipitation anomaly outlook from the Climate Prediction Center, December 26, 2016.

 Posted by at 6:33 am

More agreement on White Christmas

 Models, Northern Arizona Weather, Winter Storms  Comments Off on More agreement on White Christmas
Dec 192016
 
Snow Miser (Christmas Specials Wiki)

Monday morning forecasts are tricky. Everything seems to change as people show up to work and pay more attention to what’s going on with the weather and the computer models. Still, this morning, there is more agreement between the GFS and Navy models.

The Navy model shows precipitation starting on Friday afternoon and lasting at least into Saturday. It may even last through the entire day. Also, the Navy model shows easily over half an inch of water. The storm appears to be a cut-off low pressure system. The Navy seems to do better at forecasting these. Their temperature model show relatively high snow levels. I think the precipitation is most likely to be snow.

6 hour total precipitation ending Friday evening, December 23, 2016. (US Navy NoGaps model)

6 hour total precipitation ending Friday evening, December 23, 2016. (US Navy NoGaps model)

The GFS model from the Climate Prediction Center shows a storm arriving later and producing but producing similar precipitation amounts. It also shows warmer temperatures through the day on Saturday. This would limit snowfall.

We’ll see what happens. Everything seems to change by Monday afternoon.

48 hour total precipitation amounts Ending Christmas morning,from the GFS model. (Climate Prediction Center)

48 hour total precipitation amounts Ending Christmas morning,from the GFS model. (Climate Prediction Center)

I used the image below as the featured image. Here is a link to the page that talks about the Snow Miser. It’s worth a read, and the TV show is worth watching. I think it sums up this upcoming storm.

Snow Miser (Christmas Specials Wiki)

Snow Miser (Christmas Specials Wiki http://christmas-specials.wikia.com/wiki/Snow_Miser)

 Posted by at 4:49 am

Did anyone order a White Christmas?

 Models, Northern Arizona Weather, Winter Storms  Comments Off on Did anyone order a White Christmas?
Dec 102016
 
6-10 and 8-14 day precipitation outlooks from the Climate Prediction Center, December 9, 2016)

I’m hoping I can bring some winter with me next weekend. And, it looks very much like I can. The jet stream shift continues in the computer models. The timing of the storm is Friday morning through Saturday afternoon. Here is the 24 precipitation total ending

24 hour total precipitation ending Saturday morning, December 17, 2016. (GFS Model from TropicalTidbits.com)

24 hour total precipitation ending Saturday morning, December 17, 2016. (GFS Model from TropicalTidbits.com)

I used the precipitation total instead of snowfall because the temperatures will most likely be warm. The snow levels will be higher than recent storms. As a result, the snowfall picture isn’t as pretty or colorful. With the warm temperatures and high precipitation amounts, the snow could be wet and heavy around Flagstaff.

But wait, there’s more. Looking beyond next weekend, the pattern continues to breakdown. A strong system may move up from the southwest and across Arizona during the week before Christmas. It’s still a long way off. Both events are leading to great 6-10 and 8-14 precipitation outlooks.

6-10 and 8-14 day precipitation outlooks from the Climate Prediction Center, December 9, 2016)

6-10 and 8-14 day precipitation outlooks from the Climate Prediction Center, December 9, 2016)

 Posted by at 1:29 am

Is this the picture for this winter?

 Models, Northern Arizona Weather, Winter Storms  Comments Off on Is this the picture for this winter?
Dec 082016
 
Jet stream forecast for Saturday morning, December 17, 2016. (Tropical Tidbits)

The jet stream is pushing storms mostly to the north of Arizona. Many strong storms have recently missed Arizona, but left snow and rain from Northern California to Colorado. Currently, the jet stream seems to be stable in it’s northerly trek. Notice the reds and purples in the image below. Will this be the trend for the whole winter?

 

Jet stream forecast for this weekend. (Tropical Tidbits)

Jet stream forecast for this weekend. (Tropical Tidbits)

I hope not. A storm has been dropping in and out of the computer models around December 17. The jet stream will drop south across the state and move a low pressure system across the state. This should be good news.

Jet stream forecast for Saturday morning, December 17, 2016. (Tropical Tidbits)

Jet stream forecast for Saturday morning, December 17, 2016. (Tropical Tidbits)

While it is good news, the current precipitation forecast is not very high.

24 hour total precipitation ending Saturday morning, December 17, 2016. (Tropical Tidbits)

24 hour total precipitation ending Saturday morning, December 17, 2016. (Tropical Tidbits)

It’s at least a shot at a change to a wetter pattern. I’m skeptical.

 Posted by at 4:13 am

This winter will be difficult to forecast

 Models, Northern Arizona Weather, Outlooks  Comments Off on This winter will be difficult to forecast
Dec 022016
 
Global Tropical Sea Surface Temperature Animation from the Climate Prediction Center. (23 November 2016)

Over the last week, I’ve watched the computer models bounce around. For the most part, the precipitation part of the models has calmed down to indicate two weeks of mostly dry weather for Arizona…or so I thought. The temperature models have been worse the last few days. Devastating cold and wonderful warmth are the walls the models are bouncing off. Yesterday, I almost wrote a post about how incredibly warm it would be next week. This morning, December 8 shows up in the computer models with Flagstaff 7-10 degrees below normal. By the following weekend, temperatures are 4 or 5 degrees above normal. I’m positive it will look different again tomorrow. But, why?

So, a few years ago, in a place off the western coast of North America, an anomalous blob of warm water (aka The Blob) gathered. It was following the Ridiculously Resilient Ridge. (How can a resilient ridge of high pressure, and a blob of warm water can get Wikipedia pages, and I can’t?) Both of these features interfered with forecasting because of the alterations they made to the weather patterns.

Well, the ridge is gone. Most likely this is because it ran out of ridiculousness. The warm blob is now gone, too. Not only gone, but currently replaced by a “cold blob.” The cold blob has yet to ascertain Wikipedia status. Below is the global sea surface temperature and temperature anomaly animation from the Climate Prediction Center.

Global Tropical Sea Surface Temperature Animation from the Climate Prediction Center. (23 November 2016)

Global Tropical Sea Surface Temperature Animation from the Climate Prediction Center. (23 November 2016)

You can watch the remnants of the warm blob fade away as the cold blob migrates from Eastern Russia to the east. Also, you can see the weak La Niña grow across the Equatorial Pacific. Both of these cold water features are going to make forecasting more complex. I think that’s why the forecasts keep bouncing around.

The Navy’s NoGaps forecast model has a bit of moisture in the forecast for the middle of next week. The GFS model has none, as of this post. This will be an interesting winter.

6-hour precipitation rate for Wednesday morning, December 7, 2016. From the US Navy

6-hour precipitation rate for Wednesday morning, December 7, 2016. From the US Navy

 

 Posted by at 11:30 pm
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