A Cooling Thought

And now for something completely different: average temperature at the Amundsen–Scott South Pole Station in May was -80.7F, making this the coldest May of record there. The high temperature for May was -56F, the low -103F.

New Fire

Brand new fire just northeast of Murphy Dome down along the Chatanika River, about eight miles north of home here on Keystone Ridge. Another fire in Washington Creek beyond the Chatanika. Photo taken about 15 Mile Murphy Dome Road about 245pm. Arrgg…

Snow and Ice, or Lack Thereof

Here is a 500 meter resolution MODIS image from 255pm Sunday of northern Alaska. There is still a fair bit of snow cover close to the Beaufort Sea coast, and a lot of open water in both the Beaufort and Chukchi Seas for so early in the summer. According to the University of Illinois' Cyrosphere Today website, in both regions, areal ice cover is now 10 to 20 percent below the 1979-2008 average.

Early season Heat

Bettles set a new record high Saturday with a high of 83F. Tanana reported a high of 89F but that may be bogus: the highest hourly temp was 84F. Fairbanks had 86F, not a record.

Here on Keystone Ridge, the high of 83F is the warmest of record in 15 years of obs, and the low was only 64F, also a new record for May here.

Cooler today as the thermal trough as re-centered over the northeast Interior and a southwest breeze has developed. This has the added benefit of clearing out all the smoke, at least for the time being,

Revealing Photo

Here is the NOAA-19 Polar Orbiter visible image from 122pm ADT Saturday. Lots of interesting stuff on here. Fairbanks is near the northern edge of the smoke from the Volkmar East fire. Cumulus building over the Tanana-Yukon uplands. On the North Slope there is still some snow cover. Of more import though is the vast amount of open water now showing up off the North Slope coast.

Heat and Strong Inversions

The high of 85F on Friday at Fairbanks International easily broke the previous record of 82F set way back in 2010, and was the warmest May temperature since 1995. Most long term observation sites also set record highs, including 85F at Tanana, 82F at Bettles and 79F at Fort Greely (where some from the Volkmar East fire may have kept temps a couple degrees cooler).
Based on data since 1918, the 85F at Tanana appears to have tied the all-time May record high temperature.

Other high temperatures included 86F a Goldstream Valley Bottom, 84F at Nenana, 83F at North Pole and 79F here on Keystone Ridge.

In order to get this hot, fairly clear skies and a dry airmass are required, and these are the same ingredients needed for a decent nocturnal inversion. And lo, here are some low temperature Friday morning:

Salcha River RAWS: 30F
Goldstream Creek: 34F
Goldstream Valley Bottom: 36F
North Pole: 43F
Fairbanks IA: 49F
Keystone Ridge: 58F
Cleary Summit: 61F

So in spite of the fact the sun is up for 20 hours a day, we had an early morning inversion that would be respectable in December!

Record High at Fairbanks

83F at 5pm at Fairbanks International Airport: a new record high for May 27th.
Eielson AFB has had a high of 82F so far, tying the record for the date. More records will be set as the coop observations come in.

Here on the ridge, 79F so far.

The warmest non-RAWS temperature so far is 84 at Nenana. The upper 80s at various RAWS are sun effected due to the overly small, unaspirated radiation shield.

Sunrise at Fort Yukon

The sun peeks above the horizon at Fort Yukon. Photo from the FAA webcam at 254am ADT Friday.

Record High Temperatures Tied in the Fairbanks Area

The high temperature in Fairbanks on Thursday was 80F, tying the record set last year and several previous years. Likewise, the high of 79F at Eielson AFB tied the record high. The record high at Fairbanks and Eielson on Friday is 82F, and this is likely to be either tied or broken.
The Aurora cooperative in Fairbanks had 81F, which is the warmest official temperature so far reported.

Record High Temps on the Way

Temperatures will approach record high levels in the Interior over the next several days, but especially Friday, when some records are very likely to fall as the ridge aloft squashes convection. Saturday will likely be the warmest day, with low to mid 80s likely, but for locations that have observations going back to 1947, the 28th is generally the all-time record high for May, which is 90F, and hopefully that is out of reach!

Lightning Cranking Up

Wednesday was the most active lightning day so far this season, with just under 1300 strikes. The strikes on the Seward Peninsula are remarkably early in the season. Image from the Alaska Fire Service.

Summers are Starting Earlier in Fairbanks

Here is an update of some work I did a few years ago. The research question is: is summer, and the attendant threat of fires, starting earlier?

Since one warm day does not summer make, we need to use some threshold that integrates over a period of time. As a first crack I calculated daily 7-day running mean temperatures and then set the start of summer as the first day when this value was ≥55F. Offhand, this seems to me to be correlated with increased activity in the biotic world. By this criteria, the summer started in Fairbanks this year on Friday, May 20th.

What I've plotted here is then the 5 year running mean of this date, in order to smooth out the year to year variability. As you can see, there as been a fairly dramatic trend toward an earlier start of summer since the mid 1940s, even with the short-lived spike around 2000.

First 70 Degree Day on Keystone Ridge

Updated:
High temperature here on Keystone Ridge Tuesday was 74F, the first 70 degree day of the summer. This is almost exactly average for the past 15 years.

Rain, Whither Art Thou?

Here on Keystone Ridge, several long lasting showers moved through overnight, bringing a total of 0.20 inches of rain. I thought "Yeah, rain on the Moose Mountain Fire, and this will help moisten things up overall". Alas, we just got lucky.

Rainfall the past 24 hours are mostly 0.01 inches or less, including 0.01 at the Goldstream Creek cooperative station, less than two miles from the fire. North of Goldstream, most places received some rain, including 0.16 inches at Caribou Peak, north of Poker Flats, and 0.12 inches at the coop station at 43 Mile Steese Highway. Fairbanks Airport has received just 0.01 inches of precipitation this month; there is still more than a week left in the month, but for what it's worth, the record low precip for May is 0.01 inches set in 1915. The modern era record is 0.07 inches in 1957.

The Way Summer Comes

Green-up progressing up the south-facing slopes while snow patches cling to depressions on the north side of the ridge line.Photo Sunday afternoon from near the top of Murphy Dome, looking west-southwest.

Fire in Goldstream Valley

There is large fire burning up the north side of the ridge above Goldstream Valley, reportedly started by power lines arcing in the high winds. Photo by Julie M. looking from the IARC building looking north, about 440pm ADT

6pm Friday update: flames on the top of ridge clearly visible from IARC. This is very bad.

830pm Saturday update: 130+ people are working this fire, and it has been much less active today. Amazingly, apparently no injuries and no homes lost. However, unseasonably warm and mostly dry weather will continue for the indefinite future, which means this will be of concern for a long time to come.

Dramatic Dry Push

One of the more dramatic chinook-forced dry lines that I recall moved through Fairbanks on Friday afternoon. Note that sharp drop in dew point between 21 and 22 UTC (1 and 2pm ADT) and the spike in the winds. There was even one lightning strike just south of Livengood in the leading edge of the dry line.

Green-up in Context

With spring 2011 green-up now accomplished, here is a histogram of green-up dates at Fairbanks since 1974. Obviously, date of green-up is not normally distributed, rather, there is a sharp early peak followed by a long tail of later dates.

First 70F of the year: updated

The high Tuesday evening at the Fairbanks International Airport was 73F. So while the first 60 degree temperature, which was on Saturday, was more than two weeks later than average, the first 70 degree day was three days earlier than average.

The warm weather spurred a very dramatic green-up Tuesday afternoon all around town.
Instant summer.

FAA WebCam at Central

New FAA Webcam at Central came online last week. Here's the north-looking cam Tuesday afternoon. Nice view.

Green-up Pending

A few trees around UAF are starting to leaf-out now, and with well above normal temperatures forecast for the rest of the week, green-up should occur in the next few days. Green-up of West Chena Ridge as seen from UAF has been recorded since the mid-1970s. This year will be latest green-up since 2002.

First 60 Degree Day in Fairbanks

The high temperature Saturday in Fairbanks was 65F, the warmest day of the year so far and the first day it's been 60F or higher. This is two weeks later than the mean date for the first 60 degree temperature of the year. Since 1970, only twice has the first 60 degree temperature been later than May 14th. Here on Keystone Ridge, the high was 57F, and in the nearly cloud-free sunshine the snow patches decreased notably. The mild weather should allow for green-up to be sometime this week. Of course, in the northern Interior, spring has a ways to go. Here is a Sunday morning photo from the FAA webcam at Arctic Village.

Cool start to May

I missed some cool weather while I was gone. Here is a plot of max and min temperatures and daily departure from normal for Fairbanks thus far this month. Here on Keystone Ridge there are still plenty of patches of snow around.

Cool weekend?

I'll be back East visiting family for a week, so little or no blogging. Could be a cool weekend here.

Barrow Twilight

Continuous sunshine at Barrow is still a week away, but it's plenty light overnight. Here's looking northwest at 138am Monday, from UAF's sea ice camera.

April Weather Summary

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1113 AM AKDT SUN MAY 1 2011

...FAIRBANKS WEATHER SUMMARY FOR APRIL...

...A VERY NORMAL MONTH...

TEMPERATURES FOR APRIL IN FAIRBANKS AVERAGED ALMOST EXACTLY
NORMAL. SOMEWHAT COOLER THAN NORMAL WEATHER AT MID-MONTH WAS
BALANCED BY WARMER THAN NORMAL TEMPERATURES THE LAST 10 DAYS OF THE
MONTH. OVERALL...THE AVERAGE HIGH WAS 44 DEGREES AND THE AVERAGE
LOW WAS 20 DEGREES. THE AVERAGE TEMPERATURE OF 31.8 DEGREES FOR APRIL
WAS JUST 0.1 DEGREES ABOVE NORMAL. THE HIGH TEMPERATURE FOR THE
MONTH WAS 59 DEGREES ON THE 23RD AND 24TH. THE LOW WAS 15 BELOW ON
THE FIRST.

PRECIPITATION WAS CHARACTERISTICALLY LIGHT. AT THE AIRPORT THE
TOTAL PRECIPITATION WAS JUST 0.07 INCHES FROM 1.7 INCHES OF SNOW
ON THE 7TH AND 8TH. TOTAL PRECIPITATION WAS SOMEWHAT HIGHER IN
OTHER PARTS OF THE AREA...INCLUDING 0.16 INCHES AT THE UNIVERSITY
OF ALASKA...0.17 INCHES IN GOLDSTREAM VALLEY AND 0.28 INCHES AT
KEYSTONE RIDGE.

THE WINTER SNOW PACK SLOWLY MELTED AWAY DURING THE MONTH...AND WAS
GONE AT THE AIRPORT BY THE 27TH. THIS IS ONLY A FEW DAYS LATER
THAN THE LONG TERM AVERAGE. WITH NIGHTTIME LOWS NEAR OR BELOW
FREEZING THROUGH THE END OF THE MONTH...BREAK-UP ON AREA RIVERS
WAS ONLY SLOWLY GETTING UNDERWAY...NO SIGNIFICANT ICE JAM FLOODING
PROBLEMS THUS FAR THIS SPRING.

LOOKING AHEAD TO MAY...WARMING CONTINUES AS THE SUN GETS HIGHER IN
THE SKY EACH DAY. AVERAGE HIGH TEMPERATURES INCREASE FROM 52 ON
THE FIRST TO 65 ON THE 31ST. AVERAGE LOW TEMPERATURES INCREASE
FROM 30 ON THE FIRST TO 44 AT MONTHS END. IN THE PAST 104
YEARS...MAY TEMPERATURES HAVE RANGED FROM A HIGH OF 90 DEGREES IN
1947 TO A LOW OF 1 BELOW IN 1964.

NORMAL MAY PRECIPITATION IS 0.60 INCHES...NEARLY FOUR TIMES THE
APRIL AVERAGE. MOST OF THIS FALLS AS RAIN...AS TWO-THIRDS OF MAYS
HAVE NO MEASURABLE SNOWFALL. ON RARE OCCASIONS SIGNIFICANT SNOWFALL
CAN OCCUR IN MAY...AND ACCUMULATING SNOW EARLY IN THE MONTH IS MUCH
MORE COMMON AT HIGHER ELEVATIONS. OVER THE PAST 80 YEARS...MAY
SNOWFALL HAS EXCEED THREE INCHES JUST FOUR TIMES IN FAIRBANKS.

POSSIBLE SUNSHINE INCREASES FROM 17 HOURS ON THE FIRST TO OVER 20
HOURS BY THE END OF THE MONTH. BY MID-MONTH ENOUGH TWILIGHT
PERSIST ALL NIGHT TO ALLOW FOR MOST OUTDOOR ACTIVITIES.

$$
RT MAY 11