Monsoon season to start in earnest next weekend

 Climate, El Nino/La Nina, Models, Monsoon, Northern Arizona Weather, Outlooks  Comments Off on Monsoon season to start in earnest next weekend
Jul 022017
 
Dew point temperature outlook for Saturday afternoon, July 8, 2017, from the GFS model at TropicalTidbits.com.

In June, there have already been several thunderstorms and rain showers. But, a sustained monsoonal flow has been mostly absent. Dew point temperatures will rise throughout the week, with most Arizona being in the mid-40s by next weekend.

Dew point temperature outlook for Saturday afternoon, July 8, 2017, from the GFS model at TropicalTidbits.com.

Dew point temperature outlook for Saturday afternoon, July 8, 2017, from the GFS model at TropicalTidbits.com.

While isolated thunderstorms would be come more frequent this week, next saturday is the first day that seems to have pretty good areal coverage.

24-hour total rainfall forecast for next Saturday, July 8, 2017, from the GFS model at TropicalTidbits.com.

24-hour total rainfall forecast for next Saturday, July 8, 2017, from the GFS model at TropicalTidbits.com.

One last note, the start of the season should be strong. The 6-10 and 8-14 day outlooks from the Climate Prediction Center show above average precipitation. The longer range 1 and 3 month outlooks only show normal precipitation chances. I think these may change the next time they are run since the El Niño outlook has a decreased likelihood of it occurring this year.

6-10 day precipitation outlook from the Climate Prediction Center.

6-10 day precipitation outlook from the Climate Prediction Center.

 

8-14 day precipitation outlook from the Climate Predication Center.

8-14 day precipitation outlook from the Climate Predication Center.

 Posted by at 9:13 am

Another long break and a long delay to monsoonal flow to Flagstaff

 El Nino/La Nina, Lake Powell, Models, Monsoon, Northern Arizona Weather, Outlooks  Comments Off on Another long break and a long delay to monsoonal flow to Flagstaff
Jun 242017
 
The Partheonon at night, May 2017.

Yes, my last post was on May 4. Here we are several weeks, and European trips, later. Since May 4th, I have travelled to Prague, Greece, Italy, Austria and the far south of Germany. Prague was a work trip to see some stunning work presented! Greece was a week long sailing trip that came about because of the 40th birthday parties of a couple friends. Athens is truly striking! Italy was for a long weekend by the Gardasee (Lake Garda). Austria is in between, and with beautiful springtime green meadows against the rocky Alps. Ah! And now the weather!

The Partheonon at night, May 2017.

The Parthenon at night, May 2017.

Of course it’s fire season. I’m surprised by the number of fires and the intensity of the fire near Brian’s Head. It’s been a fairly wet winter and spring for most of the southwest. One of the indicators of this is the meteoric rise in Lake Powell. It is the deepest it has been on this date since 2011. It could be the second deepest summer out of the last decade. The lake hit it’s low point, just shy of 3594 feet in early spring. Currently, it is around the elevation of 3633 and still rising several inches per day. A wet year so far.

Lake Powell water level from water-data.com

Lake Powell water level from water-data.com. Notice it’s more like the last 5 years.

Now, the monsoon season. I realize there have been several faux monsoon storms. They were more driven by frontal systems passing to the north of Arizona, than a sustained moist flow from the south. The good news is that the heat has arrive to start the monsoon engine. Joe D’Aleo has written a nice summary of how the heat drives the flow. You can also take a look at my Monsoon Mechanics page.

The less good news is that the current computer forecasts point to the flow starting very much to the east of Flagstaff. It maybe after the 4th of July before the rains start in earnest. Below is a recent GFS model out look for precipitation between now and July 4. You can see only a small amount of precipitation predicted during this time frame.

Precipitation outlook between now and July 4, 2017 from the GFS model on TropicalTidbits.com

Precipitation outlook between now and July 4, 2017 from the GFS model on TropicalTidbits.com

Back to the better news, the outlook for the development of El Nino is low. El Nino conditions include the development of anomalous winds that can cut across the moisture flow, sending it elsewhere. Hopefully, when the season starts it will be a normal one.

Oh wait, what is a normal monsoon season?

 Posted by at 4:21 am

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

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

Wet end to February?

 Northern Arizona Weather, Outlooks, Winter Storms  Comments Off on Wet end to February?
Feb 052017
 
Experimental precipitation outlook for weeks 3-4 in the future. (Climate Prediction Center, 3 Feb. 2017)

With nearly 9 inches of precipitation between December and January, Things have been mostly dry since January 25. Next week, there is an occasional chance for flurries or light rain. It has been quite a change as the main storm track has been to the north. The current longer range outlooks for the second half of February are looking wetter.

Last Thursday, the Climate Prediction Center published their experimental 3 and 4 week outlook. It shows the potential for another round of wet weather.

Experimental precipitation outlook for weeks 3-4 in the future. (Climate Prediction Center, 3 Feb. 2017)

Experimental precipitation outlook for weeks 3-4 in the future. (Climate Prediction Center, 3 Feb. 2017)

This outlook is for February 18-March 3. Today, a run of the GFS model shows the potential for a significant storm around February 19. This is still a long way in the future. There are a few weaker storms in the computer model in the meantime. Stay tuned.

GFS model precipitation outlook for the morning of Sunday, February 19, 2017. (Image from Tropical Tidbits).

GFS model precipitation outlook for the morning of Sunday, February 19, 2017. (Image from Tropical Tidbits).

 

 Posted by at 10:47 am

Is snow season over?

 Northern Arizona Weather, Outlooks  Comments Off on Is snow season over?
Jan 252017
 
8-14 day precipitation outlook from the Climate Prediction Center.

With 43 inches of snow and 4.5 inches of water for the month to date, the next two weeks are looking remarkably dry. The question is how long will the dry trend last? The latest 8-14 day outlook from the Climate Prediction Center sums it up. Flagstaff ends up on the thin border between above and below normal precipitation. Will another snow storm hit after February 7?

8-14 day precipitation outlook from the Climate Prediction Center.

8-14 day precipitation outlook from the Climate Prediction Center.

 Posted by at 11:28 am

Navy says we may have a very White Christmas

 Northern Arizona Weather, Outlooks, Winter Storms  Comments Off on Navy says we may have a very White Christmas
Dec 182016
 
6-hour precipitation outlook from the U.S. Navy's NoGaps computer model for Friday evening, December 23, 2016.

I was feeling under the weather. Both because I have a cold, and the GFS computer model was not predicting any precipitation. Below is the 24 hour precipitation GFS model forecast for Friday, December 23, 2016. You’ll notice that the Arizona is covered in white, meaning no rain or snow. The rest of the intervening time has no snowfall predicted for Flagstaff.

24 hour total precipitation late Friday night, Dec. 23, 2016 forecast from the GFS computer model, via TropicalTidbits.com.

24 hour total precipitation late Friday night, Dec. 23, 2016 forecast from the GFS computer model, via TropicalTidbits.com.

So, I decided to check with the Navy to see if they thought the previously forecasted storm had vanished. They have a much different outlook for a similar time period. Their forecast below is for 6 hours, ending late Friday evening.

6-hour precipitation outlook from the U.S. Navy's NoGaps computer model for Friday evening, December 23, 2016.

6-hour precipitation outlook from the U.S. Navy’s NoGaps computer model for Friday evening, December 23, 2016.

This is a much different picture. The Navy has the precipitation starting on Friday morning and continuing through Saturday morning. If the Navy is correct, there could be significant snowfall during this time.

 Posted by at 6:29 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

Everything changes on the Monday after Thanksgiving

 Models, Northern Arizona Weather, Outlooks  Comments Off on Everything changes on the Monday after Thanksgiving
Nov 292016
 
6-10 day precipitation anomaly outlook from the Climate Prediction Center on November 28, 2016

Computer models need tweaking to adjust to what’s really going on in the world. It looks like quite a bit changed between Sunday and Monday. The real timeline is probably between last Wednesday and Monday. On weekends and holidays, the computer models more or less independently produce the 6-10 and 8-14 day outlooks at the Climate Prediction Center. On normal workdays, they are adjusted by real humans. Like every Monday after Thanksgiving, huge adjustments were required.

I saved the outlooks from Sunday, and they are below.

6-10 day precipitation anomaly outlook from the Climate Prediction Center on November 28, 2016

6-10 day precipitation anomaly outlook from the Climate Prediction Center on November 27, 2016

8-14 day precipitation anomaly outlook from the Climate Prediction Center on November 28, 2016

8-14 day precipitation anomaly outlook from the Climate Prediction Center on November 27, 2016

Wow, Flagstaff was going to pretty much get clobbered with snow according to these maps. But, then Monday comes along and adjustments are made.

6-10 day precipitation anomaly outlook from the Climate Prediction Center on November 28, 2016

6-10 day precipitation anomaly outlook from the Climate Prediction Center on November 28, 2016

8-14 day precipitation anomaly outlook from the Climate Prediction Center on November 29, 2016

8-14 day precipitation anomaly outlook from the Climate Prediction Center on November 28, 2016

Looks like the future storm track will shift well to the north, and oddly to the south. Flagstaff ends up in the dry middle for two weeks.

 Posted by at 5:40 am

Weather is always odd

 Models, Monsoon, Northern Arizona Weather, Outlooks  Comments Off on Weather is always odd
Aug 112016
 

As the most recent batch of moisture, which was left over from a tropical system, starts to leave Arizona, the outlooks have switched. We still have a dry period ahead, but then more moisture will return in about a week. At least, it looks that way today.

Yesterday, NOAA increased it’s outlook for Atlantic hurricane activity for the rest of this season. As if to point out who’s in charge, the computer models and Mother Nature removed any hint of future development in the next two weeks. Still, we are in the season and tropical activity can spin our monsoon season any which way. Hurricanes affect the weather for thousands of miles. With none in the plans, after the upcoming dry spell, thunderstorms should make a comeback.

To date in August, the Flagstaff Airport has received 2.32 inches of rain. an average or above average month is at hand. By comparison, Munich has received nearly 3 inches in August, and close to 11 inches in the last 30 days.

 Posted by at 9:35 pm
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