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
Dec 012010
 

It’s been a while since I can remember a record breaking, winter time low. Yesterday the Flagstaff Airport reported -4 as the temperature. This broke a record set in 1975.

With that said, the rest of this week should be warmer and nice. My personal T-Model continues to show a good chance for a storm between Monday and Wednesday next week. The GFS model shows something weaker, more to the north and sooner. NOGAPS shows a good southern track, later and stronger.

 Posted by at 6:53 am
Nov 302010
 

Well, here is my T-Model outlook for Friday to Thursday, December 5-11.

This is a very novel and proprietary model. The key to it is my confidential set of inputs.

Stu T-Model for precipitation probably, December 5-11, 2010

Stu T-Model for precipitation probably, December 5-11, 2010

Given the inputs to the T-model, and current NOGAPS and NOAA computer models, it looks like there could be a good chance for a cut-off low pressure system to form off the coast of California next week and move over Northern Arizona. This could be a significant storm. However, cut-of low pressure systems are notoriously difficult to forecast.

On another note, if you read the Forecast Discussion from the National Weather Service, you should look for the discussion provided by Peterson. Here is one from this morning:

000
FXUS65 KFGZ 301028
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
330 AM MST TUE NOV 30 2010

.SYNOPSIS...COLD AND DRY CONDITIONS WILL PERSIST TODAY BEFORE A
WARMING TREND DEVELOPS FOR THE REMAINDER OF THE WEEK.

&&

.DISCUSSION...LOW-LEVEL EASTERLY WINDS WILL PERSIST TODAY...ALTHOUGH
THEY WILL BE QUITE LIGHT. THIS WILL KEEP COLDER AIR TRAPPED OVER
MUCH OF NORTHEASTERN ARIZONA...INCLUDING THE NORTH-FACING SLOPES OF
THE MOGOLLON RIM. THIS...COMBINED WITH A VERY COLD START TO THE
DAY...WILL MAKE FOR ANOTHER AFTERNOON OF BELOW NORMAL TEMPERATURES.
BY WEDNESDAY...THROUGH FRIDAY OR SATURDAY...HIGH PRESSURE WILL
AMPLIFY OVER ARIZONA...WITH LOW-LEVEL WINDS BECOMING SOUTHWESTERLY.
THIS WILL MAKE FOR A SUBSTANTIAL WARMING TREND AND CONTINUED DRY
CONDITIONS. MODELS STILL HINTING AT THE NEXT SYSTEM BEING LATE IN
THE WEEKEND...OR EARLY NEXT WEEK. STRENGTH...TIMING...AND LOCATION
ARE ALL OVER THE PLACE...SO LOW POPS AND MODEST COOLING ARE ALL WE
CAN REALLY GO WITH FOR NOW.

&&

.AVIATION...FOR THE 12Z PACKAGE...VFR CONDITIONS WILL PREVAIL
THROUGH THE TAF PERIOD...WITH MOSTLY CLEAR SKIES...AND WINDS
GENERALLY 10KT OR LESS. A FEW HIGHER GUSTS ARE POSSIBLE THIS
AFTERNOON AT KFLG AND KGCN. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...........PETERSON
 Posted by at 6:39 am
Nov 282010
 

It’s snowing at a fairly good rate this morning. At 6:30 am, I already have about an inch of brand new white stuff. It looks like a little more moisture has made it to Northern Arizona with this storm. For Flagstaff, the National Weather Service is calling for 2-5 inches total from today into tonight.

From NOAA, one of their short-term, high resolution models shows significant potential for some areas, like the San Francisco Peaks. This model is an outlier. I think we will see a storm similar to other recent storms. 2-5 inches is probably about right.The real news will be the continued cold following the storm. Get ready for more single digit temperatures, and low snow levels. Sedona could see snow today!

NOAA's High Resolution NMM Model - Precipitation amounts for the next 48 hours. November 28, 2010

NOAA's High Resolution NMM Model - Precipitation amounts for the next 48 hours. November 28, 2010

 Posted by at 6:35 am
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