Sep 302011
 

Tropical Storm Hilary isn’t going to make it to Arizona. But, we will get a fresh shot of monsoonal flow out of the south. I don’t think we will see large amounts over the Northland. We could see strong thunderstorms and all their elements; wind, hail, etc.

Next up is cooler temperatures and a break from the recent, highly nice, unseasonably warm temperatures. The look out for the next two weeks has turned to colder forecasts. The National Weather Service has posted a nice slide today discussing the threat of frost and the average date of frost for multiple locations in Northern Arizona. We are clearly in the zone. Here is my post on Fall Freeze Probabilities.

Also, somewhere over the horizon another storm system will brush Arizona. But, this doesn’t look like the long-term trend. Unfortunately,a mostly dry, winter weather pattern could be taking a set.

6-10 day temperature outlook - Climate Prediction Center

6-10 day temperature outlook - Climate Prediction Center

 Posted by at 8:06 am
Sep 282011
 

The out look for this weekend keeps shifting around. I feel pretty confident that Hurricane Hilary will not make it to Arizona as an organized storm. But, the storm track is dipping farther to the south, and a system may move across Northern Arizona and draw the moisture from Hilary to the north. But, the models keep shifting.

I think the best bet is to plan on temperatures to start to drop as we get closer to the weekend. Also, at some point over the weekend or early next week, rain showers and thunderstorms will show up. It’s very hard to say how much rain. I am starting to doubt that we will see significant precipitation totals. Over the horizon, it looks like there is at least one potential repeat scenario.

Interestingly, my Shark Oil Barometer is showing a hint of cloudiness today. The photo below will update through the day.

Shark Oil Barometer

Shark Oil Barometer

 

 Posted by at 6:40 am
Sep 262011
 

The storm on September 14, 2011, two days after our significant hail event in Flagstaff, brought a tornado to the Peaks. Here is an image from the National Weather Service.

Arizona Snowbowl Tornado - National Weather Service

Arizona Snowbowl Tornado - National Weather Service

The NWS in Flagstaff has done a great job in recent history with their documentation of major events like this. Very nice work!

This week we should see awesome weather! Simply beautiful. Sunny, warm days and cool comfortable nights are in store. But, a significant change is still lurking for the weekend. Hurricane Hilary is current off the coast of Mexico. The National Weather Service and AccuWeather are both forecasting Hilary to run up the Baja Coast and bring cooler temperatures and elevated chances for rain this weekend for most of the state. However, I am still not sure it will happen. this morning only the GFS model shows this track. Other models show Hilary drifting about and fading into obscurity.

Summary of computer models from Weather Underground.com

Summary of computer models from Weather Underground.com

So, this weekend could be cold and wet, or it could be like the rest of the week. One particular point, the GFS model has shown the same behavior for the last week or so. Another particular point is that the NoGAPS model has shown a similar drifting track since Hilary first came into it’s time window. Keep an eye out. I’m going to close the windows on my roof this week.

 Posted by at 6:26 am
Aug 302011
 

The last few weeks have been dry. But, the Climate Prediction Center has a roar in their outlooks. This seems possible with a potential moisture surge from a tropical system coming across Northern Mexico and Texas. Also, another chance for a big East Coast storm, Katia, is on tap for the not to distant future.

8-14 day precipitation outlook from the Climate Prediction Center

8-14 day precipitation outlook from the Climate Prediction Center

 Posted by at 7:41 am
Aug 152011
 

I recorded a whopping 1.71 inches of rain by my electronic and manual rain gauges yesterday. I think this is the first time they have matched.

We’ll see as more people post their rainfall from yesterday, but it looks like it was a wet one for most of us. The National Weather Service reported 1.08 inches, just 2 hundredths of an inch short of the 1.1o inch record. According to them, that puts us a little over half an inch above average. Which means that in a single day, we went from about half an inch below average, to half an inch above average.

This morning the models are looking wet after Wednesday. The forecasts and models for the next couple days are dryer than yesterday, but things should start back up late in the week.

 Posted by at 6:56 am
Dec 312010
 

The storm track for the last few weeks has been more to the south than I would have expected. Temperatures this morning are far below normal and tonight the temperature for the Pinecone Drop will be significantly below zero. Temperatures across the Southeastern US, much of the Caribbean and most of Europe have been chilly, too. This can be attributed to the the negative phase of the Arctic Oscillation(AO) that has been in place since the middle of November.

Arctic Oscillation - Negative phase on right. Positive Phase on left. Negative phase drives the polar jet stream and storm track farther to the south.

Arctic Oscillation - Negative phase on right. Positive Phase on left. Negative phase drives the polar jet stream and storm track farther to the south.

The key characteristics of the negative phase are high pressure at high latitudes and lower pressure to the south near 45 degrees. This brings warmer than normal conditions to some places like Greenland, and colder temperatures like we have seen in the Eastern US. It is also responsible for the shift of the Western US storm track to the south, into Arizona. The question is: “Will it last?”

As I pointed out in the fall, I thought we would be moving toward a dry and potentially warm winter. December and November both started that way and shifted along the way. Here is the GFS model outlook for the AO.

Arctic Oscillation Outlook - Climate Prediction Center

Arctic Oscillation Outlook - Climate Prediction Center

The Climate Prediction Center has been fairly consistent in their outlook for the Southwest to be warm and dry this winter, even in their 6-14 day outlooks. But, with this outlook for a mostly negative AO, they seem to be changing their tune. Here are their 6-10 and 8-14 day outlooks.

Climate Prediction Center 6-10 day Precipitation Outlook

Climate Prediction Center 6-10 day Precipitation Outlook

Climate Prediction Center 6-10 day Temperature Outlook

Climate Prediction Center 6-10 day Temperature Outlook

Climate Prediction Center 8-14 day Precipitation Outlook

Climate Prediction Center 8-14 day Precipitation Outlook

Climate Prediction Center 8-14 day Temperature Outlook

Climate Prediction Center 8-14 day Temperature Outlook

In this outlook from yesterday afternoon, they are seeing a persistent storm pattern similar to the last couple weeks. What’s odd is that this morning just about every model has significantly altered the outlook to little chance of significant snow for the next couple weeks. This is a big shift. Joe Bastardi, at AccuWeather, seems to believe that this pattern is going to come to an end and we will see a return to conditions like we had in Early December.

Yesterday, I thought we were looking at a persistent storm pattern. Today, I am not so sure. But, I think the next few model runs will tell the tale. With the cooling in the North Atlantic. We could see more of an average overall winter for Flagstaff.

 Posted by at 8:52 am
Dec 162010
 

The forecasts and models continue to be all over the place this morning. It looks like we will get fairly persistent precipitation all day, but how much will be snow and how much will be rain is up in the air. The weather service shows minimal accumulations in their text forecasts for many areas. But, they have this graphic posted on their site:

Winter Weather Advisory

Winter Weather Advisory

And most models are still showing a reasonable shot at another quarter to 3/4′s of an inches of water precipitation(some even more). But, the snow level outlook is right around 6600-6700 feet. So that will we will probably bounce back and forth between rain and snow until tonight.

Snow Level - NWS - 11am MST

Snow Level - NWS - 11am MST

Looking further out, there is an on-going chance of rain and snow through the holidays. It will all depends on the the direction of the storm pump. This current storm seems to have started with the pump directed even to the south of us.

 Posted by at 6:58 am
Dec 142010
 

Yesterday was beautiful as promised. The outlook is up in the air

RECORD EVENT REPORT...CORRECTED
NATIONAL WEATHER SERVICE FLAGSTAFF, AZ
818 PM MST MON DEC 13 2010

...RECORD HIGH TEMPERATURES FOR NORTHERN ARIZONA ON DEC 13 2010...

CITY                                NEW HIGH      PREVIOUS RECORD/YEAR
BELLEMONT                              65          57         IN  2004
COTTONWOOD-TUZIGOOT NM                 76          70         IN  1996
FLAGSTAFF                              67          66         IN  1921
FORT VALLEY                            65          64         IN  1950
GREER                                  64          59         IN  2004
HEBER                                  68          67         IN  1969
NAVAJO NM                              56          54         IN  1962
PAYSON                                 69          68         IN  1969
SELIGMAN                               73          70         IN  1950
SHOW LOW                               67          63         IN  2004
GRAND CANYON SOUTH RIM                 63          62         IN  2004
WALNUT CANYON                          60          57         IN  2004

THE HIGH TEMPERATURE AT THE SEDONA AIRPORT TODAY REACHED 70 DEGREES.
THE OFFICIAL RECORD HIGH FOR TODAY IS 70 DEGREES...WHICH WAS SET AT
THE RANGER STATION IN 2004.

...RECORD HIGH TEMPERATURES FOR NORTHERN ARIZONA ON DEC 12 2010...

CITY                                NEW HIGH       PREVIOUS RECORD/YEAR
BELLEMONT                              60          60         IN  2004
COTTONWOOD-TUZIGOOT NM                 75          70         IN  1996

THESE RECORDS ARE PRELIMINARY PENDING OFFICIAL REPORTS.

The outlook is a little uncertain. Just as the North American Mesoscale (NAM) model has firmed up on a strong storm hitting the area on Thursday, the National Weather Service has moved to a fairly light 1-2 inches of snow in their forecast. Accuweather has dropped snow from their forecast. The NOGAPs model shows only a small amount of precipitation. The GFS Model shows light amounts in Northern Arizona, with heavier amounts to the south. So, which is right? I think it mostly depends on the positions of the High and Low pressure systems off the Pacific Coast. I think the graphic below captures the situation. If the pump isn’t directed at us, we get very little. If it is directed at us we get a lot.

Check Out Ken Clark’s Blog at AccuWeather. He notes the potential pineapple connection. Very nice discussion and images.

Storm Pump

Storm Pump

 Posted by at 7:09 am
Dec 132010
 

It looks like the persistent high pressure system off the coast of California and the Baja Peninsula is going to move south as a major low pressure system stations itself in the Gulf of Alaska. The opposite rotations of the two systems is going to open up a storm door that current looks to project out through Christmas. The high and low pressure systems will become a storm pump as their flows coincide in an easterly direction.

A series of troughs will be pushed through this door. Many of these will cross Northern Arizona. Each wave will bring cool temperatures and a chance for precipitation. Currently, the first wave will pass through our area from Wednesday evening to Friday morning. It looks to have only light moisture amounts with it. Looking longer, the start of next week could see over half an inch of water for the Northland.

How can you tell a change is on the way? You have an amazingly beautiful day like today is going to be. We all know it just can last. Enjoy it while you can.

 Posted by at 6:48 am
Dec 102010
 

Sorry folks, I’ve been in Japan for the last week and out of the loop as a result. Sorry the storm didn’t materialize while I was gone. It looks like there will be a couple chances for white stuff in the near future.

The normally conservative AccuWeather forecast has snow forecasted for the week of Christmas. Not just for a single day that week, but the entire week. In fact, they see the snow starting next Thursday and continuing through December 24. To some extent, his is reinforced by the GFS model which shows a strong system on a southerly track hitting Arizona on December 23. The Flagstaff forecast from the National Weather Service has a chance of snow next Thursday.

But, the high pressure off the coast of Southern California has been quite strong and unmovable of late. I am highly skeptical. But, my T-model shows a similar possibility for Christmas Week.

 Posted by at 6:39 am
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