Objective Comments and Analysis - All Science, No Politics
Primary Author Richard James
2010-2013 Author Rick Thoman
Saturday, December 31, 2011
No Solar Heating
Here's the plot of low level temperatures over the past week from a weather station located off the trail behind the IARC Building on UAF West Ridge (there are temperatures from four different heights above the ground). The vertical grid lines are at midnight. This clearly illustrates the lack of solar heating; changes in temperature are being driven entirely by variations in cloud cover.
Low Temperatures Saturday Morning
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
949 AM AKST SAT DEC 31 2011
COLD MORNING IN INTERIOR ALASKA...
A COLD AIRMASS COVERS INTERIOR ALASKA THIS MORNING. THE LOWEST
TEMPERATURES THUS FAR HAVE BEEN IN THE WESTERN INTERIOR...WHERE
SKIES HAVE BEEN GENERALLY CLEAR FOR A DAY OR MORE. IN THE CENTRAL
AND EASTERN INTERIOR...CLOUD COVER IS MORE WIDESPREAD...AND THIS
IS HELPING TO KEEP VALLEY TEMPERATURES FROM FALLING ESPECIALLY
LOW. HOWEVER...TEMPERATURES IN THE HILLS ARE QUITE COLD.
OVERNIGHT LOW TEMPERATURES THROUGH 9AM SATURDAY INCLUDE...
HUSLIA...............54 BELOW
RUBY 14 NE...........51 BELOW
BETTLES..............49 BELOW
KALTAG...............48 BELOW
GALENA...............47 BELOW
MCGRATH..............46 BELOW
RUSSIAN MISSION......45 BELOW
IN THE FAIRBANKS AREA....
FAIRBANKS AIRPORT....36 BELOW
GOLDSTREAM CREEK.....36 BELOW
UAF WEST RIDGE.......32 BELOW
EIELSON AFB..........32 BELOW
KEYSTONE RIDGE.......29 BELOW
CLEARY SUMMIT........23 BELOW
$$
RT DEC 11
NATIONAL WEATHER SERVICE FAIRBANKS AK
949 AM AKST SAT DEC 31 2011
COLD MORNING IN INTERIOR ALASKA...
A COLD AIRMASS COVERS INTERIOR ALASKA THIS MORNING. THE LOWEST
TEMPERATURES THUS FAR HAVE BEEN IN THE WESTERN INTERIOR...WHERE
SKIES HAVE BEEN GENERALLY CLEAR FOR A DAY OR MORE. IN THE CENTRAL
AND EASTERN INTERIOR...CLOUD COVER IS MORE WIDESPREAD...AND THIS
IS HELPING TO KEEP VALLEY TEMPERATURES FROM FALLING ESPECIALLY
LOW. HOWEVER...TEMPERATURES IN THE HILLS ARE QUITE COLD.
OVERNIGHT LOW TEMPERATURES THROUGH 9AM SATURDAY INCLUDE...
HUSLIA...............54 BELOW
RUBY 14 NE...........51 BELOW
BETTLES..............49 BELOW
KALTAG...............48 BELOW
GALENA...............47 BELOW
MCGRATH..............46 BELOW
RUSSIAN MISSION......45 BELOW
IN THE FAIRBANKS AREA....
FAIRBANKS AIRPORT....36 BELOW
GOLDSTREAM CREEK.....36 BELOW
UAF WEST RIDGE.......32 BELOW
EIELSON AFB..........32 BELOW
KEYSTONE RIDGE.......29 BELOW
CLEARY SUMMIT........23 BELOW
$$
RT DEC 11
Still Cold
The Environment Canada 500mb analysis valid 3am Saturday Dec 31 2011 shows the cold closed low just west of Nome, with a weaker center near McGrath. East of 150W there are more clouds than clear. so in spite of a cold airmass, valley temperatures are not excessively cold. To the west, more clear than clouds, and it is consequently colder. 8AM Saturday temperatures include 53 below at Huslia, 48 below at Kaltag and 36 below at Fairbanks Airport.
Friday, December 30, 2011
It's a Cold One
A cold airmass covers mainland Alaska today, with temperatures mostly 20 below or lower. Through noon Friday the lowest temperatures have been 51 below at both Tanana and Huslia. In Fairbanks-land, the Airport has been to 36 below and Eielson 39 below, but even in the hills most places haven well into the 20s below, including 25 below at Keystone Ridge and 23 below at the Parks Highway RWIS at the FNSB border. Cloud cover will periodically moderate temperatures somewhat east of 150W the next few days but only a slight, short lived warming of the airmass is now expected New Years Day.
50 Years Ago Today
It was 50 year ago today, Sergeant Pepper taught the band to play...
Opps, wrong event.
It was 50 year ago today though that one of the greatest Interior Alaska cold snaps of record was ending. At the left is the front page of the News-Miner.
The temperature was 40 below or lower at the Fairbanks Airport from 11am AST Dec 20th until 4am Dec 30th, 232 consecutive hours, and -55F or lower from 10pm AST Dec 27th until 1am Dec 30th, 50 consecutive hours.
Low temperatures for the event included:
Fairbanks Airport: -62F , all-time record for December
College Observatory -66F, all time record
Eielson AFB: -61F all-time record for December
Nenana: -69F
Thursday, December 29, 2011
Arctic Air
The afternoon sounding from Fairbanks shows reasonably deep cold air, with the entire sounding colder than minus 20C. I've plotted this one up to 2000 meters, as it shows that the warmest temperature in the RAOB is up near 1800 meters. This highly elevated warmest tropospheric temperature is a good marker of true "arctic air"
Cold at Last
The airmass has finally cooled in earnest in Fairbanks-land, and the effects are showing as skies clear (technical: 12Z 850mb temp -26.7C, 1000-500mb thickness 499dm). Here is the NOAA-19 Polar Orbiter infrared image from just after 5am AST Thursday, as skies were starting to clear just west of Fairbanks.
In the middle Yukon River valley, where it has been cleared for more than a day, valley temperatures were down near 40 below.
By 10am, temperatures in the Fairbanks area were down to 28 below at the Fairbanks Airport, 26 below at Goldstream Creek, 23 below at Keystone Ridge and 19 below on Cleary Summit. The North Pole and Eielson took longer to clear but will soon catch up.
In the middle Yukon River valley, where it has been cleared for more than a day, valley temperatures were down near 40 below.
By 10am, temperatures in the Fairbanks area were down to 28 below at the Fairbanks Airport, 26 below at Goldstream Creek, 23 below at Keystone Ridge and 19 below on Cleary Summit. The North Pole and Eielson took longer to clear but will soon catch up.
Monday, December 26, 2011
Inversion
Interesting inversion on the Monday afternoon sounding from Fairbanks, with four distinct layers evident in the lowest 1000 meters. The inversion right off the surface is not particularly steep (by Fairbanks standard), followed by a nearly isothermal layer between 200 and 400 meters AGL and a shallower isothermal layer between 400 and 550 meters AGL and finally a warming layer above that. Some of this stratification is wind driven, with winds here at Keystone Ridge gradually increasing during the day.
A Clear Boxing Day
Skies cleared in the Fairbanks early Monday morning, allowing for strong valley cooling. Here is the NOAA-19 polar orbiter infrared image taken about 4am AST Monday, courtesy of the NWS Alaska Region, showing the clear skies and cold valleys in the middle Tanana valley. Temperatures cooled 20+ degrees in the valleys, while in the hills temperatures fell only a few degrees. At 10am Monday, Fairbanks area temperatures vary from the mid 20s below in the cooler valley spots to 0 to 5 above at higher elevations. Here on Keystone Ridge (1600' MSL), the top of the inversion is close by, with temperatures mid-morning swinging between -4F and +3F in a matter of minutes.
My post from last Wednesday, Winter to Return, demonstrates the difficulties the numerical models have been having recently. On Wednesday both the GFS and the ECMWF, two major mid-range models were both forecasting deep cold by Monday (today). As it turned out, the observed 1000-500 mb thickness this morning at Fairbanks was 5038 gpm, an error of nearly 120 meters. That is a very large error and the result is temperatures zero to 20 below instead of 20 to 40 below.
Sunday, December 25, 2011
It's a White Christmas
To no one's surprise, it's another white Christmas in Fairbanks: snow depth at 3am Sunday was 12 inches (photo of Pioneer Park in winter from Bootsnall.com)
But there was once a Christmas that was not white. The autumn of 1934 was unusually dry and mild, and the few inch snow cover was sublimated/melted away in the super chinook of early December, when the temperature reached 50+ five straight days. After the chinook ended it remained dry. There was just over an inch of snow December 9-12th, but by the 15th there was only a trace of snow on the ground. There then was no precipitation at all until the day after Christmas. Ironically, the late winter of 1934-35 turned out to bring much above normal snowfall, and April 1935 was quite cool. As a result, the winter snowpack, after being reestablished on December 26th, did not melt out until May 8th, one of the latest dates for the spring snow melt of record.
Although snow depth data is sketchy prior to 1929, what data there is strongly suggests that this is the only "brown" Christmas since the founding of Fairbanks in 1901.
Saturday, December 24, 2011
Temperature Pops
Here's the WeatherUnderground Plot of temperature (and dew point) at the Two Rivers PWS near 24 Mile Chena Hot Springs Road. The temperature jump between 8 and 9pm is the result of an east wind picking up. Only a few mph, but enough to break the inversion. This is common in the middle Chena River valley.
The Return of Normal
Skies cleared Friday evening, and with the cooler airmass in place temperatures have returned to something like normal.
Low temperatures Saturday morning through 9AM AST include:
Eielson AFB: -29F
Woodsmoke PWS: -28F (near North Poke)
Fairbanks Airport: -25F
Goldstream Creek: -22F
Chena Hot Springs PWS: -21F
UAF West Ridge: -16F
Two Rivers PWS: -15F
Keystone Ridge: -9F
Goldstream Toboggan PWS -9F (east of Ballaine Road intersection)
Cleary Summit -6F
As an added bonus, there was a lovely aurora shining in the sky around midnight.
Low temperatures Saturday morning through 9AM AST include:
Eielson AFB: -29F
Woodsmoke PWS: -28F (near North Poke)
Fairbanks Airport: -25F
Goldstream Creek: -22F
Chena Hot Springs PWS: -21F
UAF West Ridge: -16F
Two Rivers PWS: -15F
Keystone Ridge: -9F
Goldstream Toboggan PWS -9F (east of Ballaine Road intersection)
Cleary Summit -6F
As an added bonus, there was a lovely aurora shining in the sky around midnight.
Thursday, December 22, 2011
Hot December so Far
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
124 AM AKST THU DEC 22 2011
THE AVERAGE TEMPERATURE AT THE FAIRBANKS INTERNATIONAL AIRPORT
FOR THE FIRST THREE WEEKS OF DECEMBER WAS 13.5 DEGREES...A STUNNING
16.8 DEGREES ABOVE NORMAL. THIS IS THE SECOND WARMEST FIRST THREE
WEEKS OF DECEMBER IN MORE THAN A CENTURY OF WEATHER OBSERVATIONS
IN FAIRBANKS. THE ONLY WARMER START TO DECEMBER WAS IN 1986...WHEN
THE AVERAGE TEMPERATURE THROUGH THE 21ST WAS 13.8 DEGREES.
$$
RT DEC 11
NATIONAL WEATHER SERVICE FAIRBANKS AK
124 AM AKST THU DEC 22 2011
THE AVERAGE TEMPERATURE AT THE FAIRBANKS INTERNATIONAL AIRPORT
FOR THE FIRST THREE WEEKS OF DECEMBER WAS 13.5 DEGREES...A STUNNING
16.8 DEGREES ABOVE NORMAL. THIS IS THE SECOND WARMEST FIRST THREE
WEEKS OF DECEMBER IN MORE THAN A CENTURY OF WEATHER OBSERVATIONS
IN FAIRBANKS. THE ONLY WARMER START TO DECEMBER WAS IN 1986...WHEN
THE AVERAGE TEMPERATURE THROUGH THE 21ST WAS 13.8 DEGREES.
$$
RT DEC 11
Wednesday, December 21, 2011
Winter to Return
The warm pattern that has been in place since November 30th is coming to an end, to replaced by chilly, though not super cold temperatures. Here is the forecast for 3am Monday December 26th from the GFS. The dashed lines are 1000-500mb thickness, a measurable of the mean air temperature in the lowest half of the atmosphere. The 492 thickness contour right near Fairbanks (=4920 geopotential meters) is pretty cold and will easily support valley temps in the -40s and -50s IF and WHERE skies are clear. Regardless, this should be good for teens and 20s below at elevation.
Monday, December 19, 2011
More on Normalized Departures
2011 Temperatures, Reprise
Sunday, December 18, 2011
Soundings from Fairbanks Sunday show the extreme warmth:
High temperatures Sunday include:
Woodsmoke PWS: 40F (near North Pole)
Eielson AFB: 39F
Fairbanks Airport: 37F
UAF West Ridge: 37F
Keystone Ridge: 33F
Cleary Summit: 33F
High temperatures Sunday include:
Woodsmoke PWS: 40F (near North Pole)
Eielson AFB: 39F
Fairbanks Airport: 37F
UAF West Ridge: 37F
Keystone Ridge: 33F
Cleary Summit: 33F
Another Hot Sunday in Fairbanks
A deep storm west of Kodiak Island has brought another Sunday Chinook to Interior Alaska. Here's the 3AM AST Sunday surface analysis from NWS Anchorage:
Temperatures in the valleys rose sharply after midnight, erasing the strong inversion from yesterday and are now near or above freezing at most low elevation sites.
The 340am AST Sunday NOAA-19 Polar Orbiter infrared image shows a classic cyclone structure:
High temperatures through 10am AST include:
Eielson AFB: 39F
Woodsmoke PWS: 38F (near North Pole)
Two River PWS: 38F
UAF West Ridge: 35F
Fairbanks Airport: 34F
Keystone Ridge: 32F
Goldstream Creek: 28F
Temperatures in the valleys rose sharply after midnight, erasing the strong inversion from yesterday and are now near or above freezing at most low elevation sites.
The 340am AST Sunday NOAA-19 Polar Orbiter infrared image shows a classic cyclone structure:
High temperatures through 10am AST include:
Eielson AFB: 39F
Woodsmoke PWS: 38F (near North Pole)
Two River PWS: 38F
UAF West Ridge: 35F
Fairbanks Airport: 34F
Keystone Ridge: 32F
Goldstream Creek: 28F
Saturday, December 17, 2011
Inverion Holds
Barrow near the Solstice
Winter solstice this year is at 830pm AST Wednesday. Here's a photo at Barrow from the Sea Ice webcam at 1235pm Saturday. This is about 40 minutes before solar noon.
Strong Inversion
Mostly clear skies the past day or so have allowed a typically strong inversion to develop in Fairbanks. Here's the temperature in the lowest kilometer of the atmosphere from the 3am AST Saturday sounding.
Low temperatures on the ground through 10am Saturday morning reflect this:
Fairbanks Airport: -10F
Chena Hot Springs: -10F
Woodsmoke PWS: -9F (near North Pole)
Goldstream Creek: -9F
College Road: -7 (NRCS SNOTEL near Fairgrounds)
UAF West Ridge: +2F
Two River PWS: 7F
Keystone Ridge: 18F
Cleary Summit: 22F
Friday, December 16, 2011
Second Warmest first half of December at Fairbanks
from my colleague Corey:
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1251 AM AKST FRI DEC 16 2011
...2ND WARMEST FIRST HALF OF DECEMBER ON RECORD AT FAIRBANKS...
THROUGH YESTERDAY THE 15TH THE AVERAGE TEMPERATURE AT THE
FAIRBANKS INTERNATIONAL AIRPORT WAS 14.1 DEGREES...WHICH WAS
17.9 DEGREES ABOVE AVERAGE. IT WAS THE 2ND WARMEST FIRST HALF OF
DECEMBER ON RECORD AT FAIRBANKS. ONLY 1934 WAS ANY WARMER...AND THIS
WAS DUE TO AN INCREDIBLE CHINOOK EARLY IN THE MONTH THAT SENT
TEMPERATURES INTO THE 50S ON 5 CONSECUTIVE DAYS...AND LED TO THE
ONLY CHRISTMAS ON RECORD WITH NO MEASURABLE SNOW ON THE GROUND AT
FAIRBANKS. IN 1934...TEMPERATURES TURNED SHARPLY COLDER THE
SECOND HALF OF THE MONTH...AND BY THE END OF MONTH IT DID NOT EVEN
END UP AS ONE OF THE TOP TEN COLDEST DECEMBERS ON RECORD. THE
WARMEST DECEMBER ON RECORD OCCURRED IN 1914 WITH AN AVERAGE
MONTHLY TEMPERATURE OF 10.2 DEGREES. TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE NORMAL FOR NEXT WEEK...INCREASING THE CHANCES THAT
THIS DECEMBER WILL GO DOWN IN THE RECORD BOOKS AS ONE OF THE
WARMEST ON RECORD.
$$
CB DEC 11
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1251 AM AKST FRI DEC 16 2011
...2ND WARMEST FIRST HALF OF DECEMBER ON RECORD AT FAIRBANKS...
THROUGH YESTERDAY THE 15TH THE AVERAGE TEMPERATURE AT THE
FAIRBANKS INTERNATIONAL AIRPORT WAS 14.1 DEGREES...WHICH WAS
17.9 DEGREES ABOVE AVERAGE. IT WAS THE 2ND WARMEST FIRST HALF OF
DECEMBER ON RECORD AT FAIRBANKS. ONLY 1934 WAS ANY WARMER...AND THIS
WAS DUE TO AN INCREDIBLE CHINOOK EARLY IN THE MONTH THAT SENT
TEMPERATURES INTO THE 50S ON 5 CONSECUTIVE DAYS...AND LED TO THE
ONLY CHRISTMAS ON RECORD WITH NO MEASURABLE SNOW ON THE GROUND AT
FAIRBANKS. IN 1934...TEMPERATURES TURNED SHARPLY COLDER THE
SECOND HALF OF THE MONTH...AND BY THE END OF MONTH IT DID NOT EVEN
END UP AS ONE OF THE TOP TEN COLDEST DECEMBERS ON RECORD. THE
WARMEST DECEMBER ON RECORD OCCURRED IN 1914 WITH AN AVERAGE
MONTHLY TEMPERATURE OF 10.2 DEGREES. TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE NORMAL FOR NEXT WEEK...INCREASING THE CHANCES THAT
THIS DECEMBER WILL GO DOWN IN THE RECORD BOOKS AS ONE OF THE
WARMEST ON RECORD.
$$
CB DEC 11
Thursday, December 15, 2011
Deep Storm
Here's the 3am AST Thursday GOES-15 image showing an intense cyclone over the eastern Aleutians. The minimum Sea Level Pressure at Dutch Harbor was 945.8mb at 2AM AST. Dutch had a peak wind from this storm of 76KT late Monday afternoon.
Wednesday, December 14, 2011
Solar Noon at Prudhoe Bay
Here's a photo, looking south from Prudhoe Bay (thanks to the FAA webcam) from just after solar noon on Wednesday.
Tuesday, December 13, 2011
Let it Snow
Snowfall during mid-winter in Interior Alaska often does not show much of valley to ridge difference. After all, precipitation is almost always snow, and the elevations where people live vary by perhaps 2000 feet (say, Nenana to Ester Dome), trivial compared to, say the vertical change over similar distances in the Rockies.
That has most definitely not been the case so far month. Here is a chart of the daily snowfall thus far this month at Fairbanks International Airport and Keystone Ridge.
There was similar, though less extreme difference last month, when the Airport measured 9.2 inches of snow and Keystone Ridge 20.7 inches.
Below is a plot the difference in total December snowfall since 1996 between the Airport and Keystone Ridge. Monthly differences have not exceeded six inches, and the difference has not been more than 50% of the total at Fairbanks: thus far this month, the difference of 14.0 inches is a stunning 241% of the Fairbanks total.
Of course, with more than two weeks left in December this difference will likely narrow, but given the usual minimal differences is unlikely to dramatically change.
That has most definitely not been the case so far month. Here is a chart of the daily snowfall thus far this month at Fairbanks International Airport and Keystone Ridge.
There was similar, though less extreme difference last month, when the Airport measured 9.2 inches of snow and Keystone Ridge 20.7 inches.
Below is a plot the difference in total December snowfall since 1996 between the Airport and Keystone Ridge. Monthly differences have not exceeded six inches, and the difference has not been more than 50% of the total at Fairbanks: thus far this month, the difference of 14.0 inches is a stunning 241% of the Fairbanks total.
Of course, with more than two weeks left in December this difference will likely narrow, but given the usual minimal differences is unlikely to dramatically change.
Monday, December 12, 2011
Messy Image
This 430pm AST Monday GOES-15 image shows lots of (disorganized) clouds across eastern mainland Alaska, while a tight cyclone is impacting the central Aleutians.
The Anchorage area received 6-12 inches of snow in town and up to two feet of new snow on the upper hillside. Amounts in Fairbanks-land have been mostly an inch or two, but with enough southwest wind to blow the snow around in town, always a notable event. However, it remains very mild, with temperatures so far stuck in the teens and 20s.
The Sea Level Pressure at Adak at 5pm AST Monday was 959mb with the low center just to their east.
Updated: The minimum pressure in this storm at Adak was 951.2mb at 1016pm AST Monday.
Saturday, December 10, 2011
Another Seward Pen Blizzard
Here's the FAA webcam shot from Nome at 1pm AST Saturday. Nome's been reporting blizzard conditions since before 10am, with winds gusting to nearly 50 mph. Similar at Golovin.
The 9am AST Saturday surface analysis from NWS Anchorage shows a complex low in the western Bering Sea.
The 9am AST Saturday surface analysis from NWS Anchorage shows a complex low in the western Bering Sea.
Snowfall Friday
Nice little snowfall in Fairbanks-land Friday.
Some totals include:
Fairbanks Airport: 2.9 inches (most any day so far this winter)
Fairbanks Mid-town: 2.5"
UAF West Ridge: 2.4"
Goldstream Creek: 2.1"
Keystone Ridge: 5.4"
The much higher amount here on the ridge was probably an elevation effect: low level west winds lifted a 1000' up from the Minto Flats, with the atmosphere unstable enough for that lift to enhance snow crystal production. Just a guess of course. However, on my home from work late Friday evening the snow amounts did not look to increase much until I started up the hill.
Some totals include:
Fairbanks Airport: 2.9 inches (most any day so far this winter)
Fairbanks Mid-town: 2.5"
UAF West Ridge: 2.4"
Goldstream Creek: 2.1"
Keystone Ridge: 5.4"
The much higher amount here on the ridge was probably an elevation effect: low level west winds lifted a 1000' up from the Minto Flats, with the atmosphere unstable enough for that lift to enhance snow crystal production. Just a guess of course. However, on my home from work late Friday evening the snow amounts did not look to increase much until I started up the hill.
Friday, December 9, 2011
Clocks Don't Matter
Classic December Day: High temperature at 1am, low temperature in the middle of the afternoon…
CDAK49 PAFG 090937
CLIFAI
CLIMATE REPORT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1237 AM AKST FRI DEC 9 2011
...................................
...THE FAIRBANKS AK CLIMATE SUMMARY FOR DECEMBER 8 2011...
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1904 TO 2011
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST
VALUE (LST) VALUE VALUE FROM YEAR
NORMAL
..................................................................
TEMPERATURE (F)
YESTERDAY
MAXIMUM 22 1258 AM 55 1934 6 16 -16
MINIMUM 0 340 PM -53 1935 -10 10 -28
AVERAGE 11 -3 14 -22
CDAK49 PAFG 090937
CLIFAI
CLIMATE REPORT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1237 AM AKST FRI DEC 9 2011
...................................
...THE FAIRBANKS AK CLIMATE SUMMARY FOR DECEMBER 8 2011...
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1904 TO 2011
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST
VALUE (LST) VALUE VALUE FROM YEAR
NORMAL
..................................................................
TEMPERATURE (F)
YESTERDAY
MAXIMUM 22 1258 AM 55 1934 6 16 -16
MINIMUM 0 340 PM -53 1935 -10 10 -28
AVERAGE 11 -3 14 -22
Monday, December 5, 2011
Winds
Fairbanks Airport reported a peak wind of 51 mph at 1021AM Monday. Gust data is only available at Fairbanks since the mid-1980s, but since then this is the highest gust of record for December. The previous record was just 38 mph on Christmas Eve 1985.
Here is a plot of winds from the NRCS SNOTEL up on Eagle Summit at Mile 107 Steese Highway (elevation 3750' MSL). Winds between an ASOS/AWOS and SNOTEL are not directly comparable, but you get the idea. The anemometer often ices up on Eagle Summit, but evidently not today.
It's been a really windy day up there! The highest gust has been 55 mph, and a quick look shows nothing that high in the past couple winters (50 mph was the highest reported in the storms last February)
Here is a plot of winds from the NRCS SNOTEL up on Eagle Summit at Mile 107 Steese Highway (elevation 3750' MSL). Winds between an ASOS/AWOS and SNOTEL are not directly comparable, but you get the idea. The anemometer often ices up on Eagle Summit, but evidently not today.
It's been a really windy day up there! The highest gust has been 55 mph, and a quick look shows nothing that high in the past couple winters (50 mph was the highest reported in the storms last February)
Storm Aftermath
Here's the 3am Monday Surface Analysis from Environment Canada. The 975mb low near Banks Island is responsible for the re-surge of winds across the area this morning.
Impacts:
Fairbanks North Star Borough Schools and State Offices are closed today (Monday) due to poor road conditions. FNSB Borough Offices and UAF are open. Fort Wainwright has "late arrival" policy in place.
Weather:
Record High Temps for December set Sunday:
North Pole: 49F (old record 47F on Dec 29 1982)
Eielson AFB: 48F (old record 47F on Dec 24 1985)
UAF West Ridge: 45F (old record 44F Dec 24 1985)
The high of 47F at Fairbanks International is the highest temperature of record in December except for Dec 4-8, 1934, when every day had a high in the 50s.
There were some big snow amounts:
Bettles: 14.3 inches Sunday
Ruby 14NE: 13.5 inches (cooperative station upriver from Ruby)
Galena: 8.0 inches
Sunday, December 4, 2011
Rain
Rain in Fairbanks Sunday afternoon evidently did not amount to much (trace to a couple hundredths), though this time of year any is a problem for roads, walkways, etc. Much higher amounts though occurred near Denali National Park, with 0.20" reported from Park Headquarters this morning and 0.30" at Healy. Nenana also received almost a tenth of an inch of rain Sunday afternoon before it changed over to snow.
Big Chinook
It appears that the temperature spiked to 47F at 1119am at the Fairbanks Airport right as the front came through, mixing out the weak inversion that was present. If this is correct, this is the highest temperature of record in December EXCEPT for the five days from December 4-8 1934, when the temperature got to 50F or higher each day. More on this to follow.
Here's the plot of temperatures from the 3am and 3pm RAOBs from Fairbanks.
That's a lot of cooling!
Here's the plot of temperatures from the 3am and 3pm RAOBs from Fairbanks.
That's a lot of cooling!
Record High Temperatures
Here's the METAR plot from 10am Sunday observations: a wind shift just came through Fairbanks: the surgace front is probably lagging a bit behind.
For climate sites that do not have records going back to the great December 1934 Chinook appear to have set or tied new December high temperatures. The following are all preliminary and subject to revision:
Eielson AFB: 48F (47F on Dec 24 1985)
UAF West Ridge: 45F (44F on Dec 24 1985)
North Pole current record for December is 47F
other daily records:
Fort Greely/Big Delta: 51F
Other high temperatures:
Rex Brige RWIS: 49F (Mile 276 Parks Hwy)
Mile 42 Steese Hwy: 47F
Nenana Hills RWIS 44F (at FNSB Borough Boundary on Parks Hwy)
Also of note:
Antler Creek RWIS (south of Healy) peak wind 81 mph at 505pm Saturday Dec 03
For climate sites that do not have records going back to the great December 1934 Chinook appear to have set or tied new December high temperatures. The following are all preliminary and subject to revision:
Eielson AFB: 48F (47F on Dec 24 1985)
UAF West Ridge: 45F (44F on Dec 24 1985)
North Pole current record for December is 47F
other daily records:
Fort Greely/Big Delta: 51F
Other high temperatures:
Rex Brige RWIS: 49F (Mile 276 Parks Hwy)
Mile 42 Steese Hwy: 47F
Nenana Hills RWIS 44F (at FNSB Borough Boundary on Parks Hwy)
Also of note:
Antler Creek RWIS (south of Healy) peak wind 81 mph at 505pm Saturday Dec 03
Extreme Heat in the Central Interior
3AM Sunday surface analysis from NWS Anchorage:
7-8am Sunday Temperatures around the central Interior
Kantishna SNOTEL: 51F
Chena Hot Springs: 50F
Nenana: 50F
Woodsmoke PWS: 49F
Eielsion AFB: 48F
Birch Lake RWIS: 48F
Denali Park AWOS: 45F
Cleary Summit: 41F
Keystone Ridge: 40F
Fairbanks Airport: 36F
Eagle Summit SNOTEL: 36F
Much more to come after I've had some coffee…
7-8am Sunday Temperatures around the central Interior
Kantishna SNOTEL: 51F
Chena Hot Springs: 50F
Nenana: 50F
Woodsmoke PWS: 49F
Eielsion AFB: 48F
Birch Lake RWIS: 48F
Denali Park AWOS: 45F
Cleary Summit: 41F
Keystone Ridge: 40F
Fairbanks Airport: 36F
Eagle Summit SNOTEL: 36F
Much more to come after I've had some coffee…
Saturday, December 3, 2011
Surface Analysis
Here's the 3pm AST Saturday surface analysis from NOAA's Ocean Prediction Center. The deep southerly flow, at least a breeze and thick cloud cover has boasted temperatures across area, resulting in frosty roads.
6pm Saturday…
Two Rivers PWS: 30F
Keystone Ridge: 30F
Clearly Summit: 29F
Fairbanks Airport 28F
Woodsmoke PWS: 28F
Eielson AFB: 25F
Goldstream Creek: 22F
Warming Up
Here's the 3pm Saturday RAOB from Fairbanks. I've plotted temperatures on the left and wind speed of the right for the lowest 1500 meters of the atmosphere. Temperatures vary between -1 and -5C and winds speeds are on the way. Free air wind speeds are nearly always higher than that reported from surface stations at similar elevation (excepting ridge top locations, e.g. like Mt Washington, New Hampshire).
Thermometer Yoyo
Early December Storm
Here's the 850mb temperature forecast for Fairbanks from the 12Z Saturday GFS. It is quite similar to yesterday's run; warm in the morning (no chance of record though as this is the anniversary of the great 1934 chinook); the cold front is a smidge faster, coming through during the afternoon followed, by about 12 hours of snow and 24 hours of gusty west to southwest winds. It's not out of the realm of reasonablity that there could be a little freezing rain right at the start, but it would not last more than minutes before changing to snow.
Friday, December 2, 2011
No Rest for the Weary
Another big storm is on the way for northern Alaska. Here are forecasts from the GFS for 3am and 3pm AST Sunday. What does this mean for Fairbanks-land?
First, Saturday night into Sunday morning, big chinook. It is very likely that it will get significantly above freezing throughout the area. Then, about as strong a cold front as ever is seen in Interior Alaska comes blasting through late Sunday afternoon or evening. Here's the forecast for the 850mb temperatures (about 4500' MSL, a decent guide to the temperature of the low level airmass).
Yes, that's plotted correctly: the model is forecasting an almost 9C fall between 3pm and 6pm Sunday. There will be snow and lots of southwest wind as the cold air returns. Above tree-line on the highways north of Fairbanks it's really going to howl. The southwest winds will break through in town too; I would not be surprised to see Fairbanks Airport report blowing snow at some point Sunday night/Monday morning.
First, Saturday night into Sunday morning, big chinook. It is very likely that it will get significantly above freezing throughout the area. Then, about as strong a cold front as ever is seen in Interior Alaska comes blasting through late Sunday afternoon or evening. Here's the forecast for the 850mb temperatures (about 4500' MSL, a decent guide to the temperature of the low level airmass).
Yes, that's plotted correctly: the model is forecasting an almost 9C fall between 3pm and 6pm Sunday. There will be snow and lots of southwest wind as the cold air returns. Above tree-line on the highways north of Fairbanks it's really going to howl. The southwest winds will break through in town too; I would not be surprised to see Fairbanks Airport report blowing snow at some point Sunday night/Monday morning.
Thursday, December 1, 2011
November Weather Summary
November Summary for Fairbanks...
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1155 AM AKST THU DEC 1 2011
...MONTHLY WEATHER SUMMARY FOR FAIRBANKS ALASKA...
...OUTSTANDING COLD SNAP MID-MONTH...
NOVEMBER 2011 WILL LONG BE REMEMBERED FOR THE MID-WINTER-LIKE COLD
SNAP WHICH SETTLED IN THE WEEK BEFORE THANKSGIVING. THE WEEK OF
NOVEMBER 15TH TO 21ST...WITH AN AVERAGE TEMPERATURE OF
30.1 BELOW...IS THE COLDEST WEEK EVER RECORDED IN FAIRBANKS BEFORE
THANKSGIVING DAY. SIX DAILY RECORD LOWS WERE SET DURING THIS
TIME...WHICH IS TRULY OUTSTANDING FOR A LOCATION WITH MORE THAN A
CENTURY OF UNBROKEN WEATHER OBSERVATIONS.
THE FIRST HALF OF NOVEMBER...WITH AN AVERAGE TEMPERATURE OF 3.0
DEGREES ABOVE ZERO WAS ONLY A BIT COOLER THAN NORMAL.
HOWEVER...THE SECOND HALF OF THE MONTH...WITH AN AVERAGE
TEMPERATURE OF MINUS 19.2 DEGREES WAS THE COLDEST SECOND HALF OF
NOVEMBER SINCE 1963.
FOR THE MONTH AS A WHOLE...AT THE AIRPORT THE AVERAGE HIGH
TEMPERATURE WAS ZERO AND THE AVERAGE LOW 17 BELOW. THE AVERAGE
TEMPERATURE LAST MONTH OF 8.2 BELOW MADE THIS THE SIXTH COLDEST
NOVEMBER OF RECORD. DURING THE PAST 50 YEARS...THE ONLY COLDER
NOVEMBER WAS IN 2006...WHEN THE AVERAGE TEMPERATURE WAS 9.9 BELOW.
THE COLDEST NOVEMBER OF RECORD WAS IN 1927...WHEN THE AVERAGE
TEMPERATURE WAS MINUS 11.2 DEGREES.
THE HIGH FOR THE MONTH WAS 25 DEGREES ON THE 4TH. THE LOWEST
TEMPERATURE AT THE AIRPORT WAS 41 BELOW ON THE 17TH...AND IS THE
FIRST TIME THE TEMPERATURE HAS FALLEN PAST 40 BELOW IN NOVEMBER
SINCE 1994. SEVEN DAYS HAD LOW TEMPERATURES OF 30 BELOW OR
LOWER...THE MOST IN A NOVEMBER SINCE 1963. SOMEWHAT LOWER
TEMPERATURES WERE RECORDED IN THE NORMALLY COLDER SPOTS...INCLUDING
49 BELOW IN NORTH POLE ON THE 17TH.
SNOWFALL WAS GENERALLY A BIT BELOW NORMAL IN THE IMMEDIATE FAIRBANKS
AREA...AND NEARLY ALL OF IT FELL DURING THE FIRST TWO WEEKS OF THE
MONTH. THE TOTAL AT THE AIRPORT OF 9.2 INCHES WAS ABOUT 4 INCHES
BELOW NORMAL. THIS MELTED DOWN TO 0.46 INCHES OF WATER...WHICH IS
ABOUT TWO-THIRDS OF NORMAL. SNOW DEPTHS INCREASED FROM 3 INCHES ON
THE FIRST TO A STEADY 7 INCHES THE LAST TWO WEEKS OF THE MONTH.
HIGHER SNOWFALL AMOUNTS WERE OBSERVED NORTH OF TOWN. FOR NOVEMBER
12.0 INCHES OF SNOW WAS MEASURED AT MILE 42 STEESE HIGHWAY. THE
KEYSTONE RIDGE COOPERATIVE STATION...NEAR MURPHY DOME...REPORTED
20.7 INCHES OF SNOW FOR THE MONTH.
WINDS WERE CHARACTERISTICALLY LIGHT IN NOVEMBER...ESPECIALLY
DURING THE COLDEST WEATHER. AVERAGE DAILY WIND SPEEDS WERE LESS
THAN TWO MPH EVERY DAY AFTER THE 13TH. ICE FOG DURING THE COLDEST
WEATHER WAS NOT ESPECIALLY DENSE.
LOOKING AHEAD TO DECEMBER...NORMAL TEMPERATURES SLOWLY DECLINE...
FROM 2 BELOW ON THE FIRST TO 7 BELOW ON NEW YEARS EVE. OVER THE
PAST 106 YEARS...DECEMBER TEMPERATURES HAVE RANGED FROM A HIGH OF
58 DEGREES IN 1934 TO 62 BELOW IN 1961. ON AVERAGE A FOOT OF NEW
SNOW FALLS DURING THE MONTH...BUT HAS RANGED FROM 50.7 INCHES IN
1984 TO JUST A TRACE IN 1969. POSSIBLE SUNSHINE DECREASES FROM 4
HOUR 42 MINUTES ON THE FIRST TO 3 HOURS 42 MINUTES FOR A FEW DAYS
AROUND THE WINTER SOLSTICE...AND THEN INCREASES THEREAFTER.
$$
RT DEC 11
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1155 AM AKST THU DEC 1 2011
...MONTHLY WEATHER SUMMARY FOR FAIRBANKS ALASKA...
...OUTSTANDING COLD SNAP MID-MONTH...
NOVEMBER 2011 WILL LONG BE REMEMBERED FOR THE MID-WINTER-LIKE COLD
SNAP WHICH SETTLED IN THE WEEK BEFORE THANKSGIVING. THE WEEK OF
NOVEMBER 15TH TO 21ST...WITH AN AVERAGE TEMPERATURE OF
30.1 BELOW...IS THE COLDEST WEEK EVER RECORDED IN FAIRBANKS BEFORE
THANKSGIVING DAY. SIX DAILY RECORD LOWS WERE SET DURING THIS
TIME...WHICH IS TRULY OUTSTANDING FOR A LOCATION WITH MORE THAN A
CENTURY OF UNBROKEN WEATHER OBSERVATIONS.
THE FIRST HALF OF NOVEMBER...WITH AN AVERAGE TEMPERATURE OF 3.0
DEGREES ABOVE ZERO WAS ONLY A BIT COOLER THAN NORMAL.
HOWEVER...THE SECOND HALF OF THE MONTH...WITH AN AVERAGE
TEMPERATURE OF MINUS 19.2 DEGREES WAS THE COLDEST SECOND HALF OF
NOVEMBER SINCE 1963.
FOR THE MONTH AS A WHOLE...AT THE AIRPORT THE AVERAGE HIGH
TEMPERATURE WAS ZERO AND THE AVERAGE LOW 17 BELOW. THE AVERAGE
TEMPERATURE LAST MONTH OF 8.2 BELOW MADE THIS THE SIXTH COLDEST
NOVEMBER OF RECORD. DURING THE PAST 50 YEARS...THE ONLY COLDER
NOVEMBER WAS IN 2006...WHEN THE AVERAGE TEMPERATURE WAS 9.9 BELOW.
THE COLDEST NOVEMBER OF RECORD WAS IN 1927...WHEN THE AVERAGE
TEMPERATURE WAS MINUS 11.2 DEGREES.
THE HIGH FOR THE MONTH WAS 25 DEGREES ON THE 4TH. THE LOWEST
TEMPERATURE AT THE AIRPORT WAS 41 BELOW ON THE 17TH...AND IS THE
FIRST TIME THE TEMPERATURE HAS FALLEN PAST 40 BELOW IN NOVEMBER
SINCE 1994. SEVEN DAYS HAD LOW TEMPERATURES OF 30 BELOW OR
LOWER...THE MOST IN A NOVEMBER SINCE 1963. SOMEWHAT LOWER
TEMPERATURES WERE RECORDED IN THE NORMALLY COLDER SPOTS...INCLUDING
49 BELOW IN NORTH POLE ON THE 17TH.
SNOWFALL WAS GENERALLY A BIT BELOW NORMAL IN THE IMMEDIATE FAIRBANKS
AREA...AND NEARLY ALL OF IT FELL DURING THE FIRST TWO WEEKS OF THE
MONTH. THE TOTAL AT THE AIRPORT OF 9.2 INCHES WAS ABOUT 4 INCHES
BELOW NORMAL. THIS MELTED DOWN TO 0.46 INCHES OF WATER...WHICH IS
ABOUT TWO-THIRDS OF NORMAL. SNOW DEPTHS INCREASED FROM 3 INCHES ON
THE FIRST TO A STEADY 7 INCHES THE LAST TWO WEEKS OF THE MONTH.
HIGHER SNOWFALL AMOUNTS WERE OBSERVED NORTH OF TOWN. FOR NOVEMBER
12.0 INCHES OF SNOW WAS MEASURED AT MILE 42 STEESE HIGHWAY. THE
KEYSTONE RIDGE COOPERATIVE STATION...NEAR MURPHY DOME...REPORTED
20.7 INCHES OF SNOW FOR THE MONTH.
WINDS WERE CHARACTERISTICALLY LIGHT IN NOVEMBER...ESPECIALLY
DURING THE COLDEST WEATHER. AVERAGE DAILY WIND SPEEDS WERE LESS
THAN TWO MPH EVERY DAY AFTER THE 13TH. ICE FOG DURING THE COLDEST
WEATHER WAS NOT ESPECIALLY DENSE.
LOOKING AHEAD TO DECEMBER...NORMAL TEMPERATURES SLOWLY DECLINE...
FROM 2 BELOW ON THE FIRST TO 7 BELOW ON NEW YEARS EVE. OVER THE
PAST 106 YEARS...DECEMBER TEMPERATURES HAVE RANGED FROM A HIGH OF
58 DEGREES IN 1934 TO 62 BELOW IN 1961. ON AVERAGE A FOOT OF NEW
SNOW FALLS DURING THE MONTH...BUT HAS RANGED FROM 50.7 INCHES IN
1984 TO JUST A TRACE IN 1969. POSSIBLE SUNSHINE DECREASES FROM 4
HOUR 42 MINUTES ON THE FIRST TO 3 HOURS 42 MINUTES FOR A FEW DAYS
AROUND THE WINTER SOLSTICE...AND THEN INCREASES THEREAFTER.
$$
RT DEC 11
Wednesday, November 30, 2011
Dramatic Temperature Swings
Interesting temperature variation the past day in Fairbanks-land. Here is a plot of hourly temperatures from a number of locations.
The max temperatures early in the morning make a useful case study: Eielson reach their max temperature when the southeast winds broke through ahead of the trough, so are hour or so earlier than the other valley locations (in spite of Eielson being the eastern-most of these stations), where the max temp occurred with a short pulse of weak southwest wind following the trough. At elevation (Keystone Ridge), there was no spike in temperature at all, where most of the wind occurred Tuesday evening.
High temps (not just hourly) occurred 5-7am:
Eielson AFB: 26F
Keystone Ridge: 21F
Fairbanks Airport: 16F
Woodsmoke PWS: 11F (near North Pole)
Goldstream Creek: 7F
Tuesday, November 29, 2011
Solar Heating or Lack Thereof
Here's a plot of the daily duration of solar heating at 65N (latitude of Fairbanks), defined as the duration the sun is 5° or more above the horizon. Note the plot extends for 15 months so to show the winter minimum. We are a week into the two months with no significant solar heating. Changes in surfaces temperatures during this time are modulated by horizontal movement of air (advection), vertical mixing (mostly wind) and presence of absence of clouds significant to reduce the continuous cooling of the top of the snow pack (long wave radiation).
Sunday, November 27, 2011
Big warm-up on the Way
Trung asked about the big warm-up in the current forecast in a couple days. Here's why:
Big pattern change is underway for Alaska and will bring much milder weather to the Interior by midweek. First, here is the 500mb heights and 850mb temperatures for this past Saturday morning (from the ECMWF). This shows a closed low west of Anchorage and a fairly chilly airmass over most of mainland Alaska; the blue colors are 850mb (~4500 MSL) temperatures of -16C or lower.
Now, here is the forecast from the 12Z Sunday ECMWF valid at 3am AST Wednesday Nov 30th. Deep southwest flow from the north Pacific covers most of the state, with the chilly air having retreated the Brooks Range. This could wind up being a fairly snowy pattern for Fairbanks-land, but as always in these situations, if the winds aloft are just a little bit too southerly, then we will "chinook out". At this point though it looks to me like the best forecast is for some snow the middle and end of this week.
Big pattern change is underway for Alaska and will bring much milder weather to the Interior by midweek. First, here is the 500mb heights and 850mb temperatures for this past Saturday morning (from the ECMWF). This shows a closed low west of Anchorage and a fairly chilly airmass over most of mainland Alaska; the blue colors are 850mb (~4500 MSL) temperatures of -16C or lower.
Now, here is the forecast from the 12Z Sunday ECMWF valid at 3am AST Wednesday Nov 30th. Deep southwest flow from the north Pacific covers most of the state, with the chilly air having retreated the Brooks Range. This could wind up being a fairly snowy pattern for Fairbanks-land, but as always in these situations, if the winds aloft are just a little bit too southerly, then we will "chinook out". At this point though it looks to me like the best forecast is for some snow the middle and end of this week.
Inversion
Big Inversion
A pretty decent inversion has developed overnight, with valley temperatures pushing 30 below and higher elevations near zero.
10AM Sunday temperatures include:
Woodsmoke PWS: -33F (near North Pole)
Eielson AFB: -29F
Fairbanks Airport: -27F
Goldstream Creek: -27F
Cleary Summit: +2F
Little Chena Ridge +1F (south of the Steese Highway)
Gilmore Trail PWS: -1F (1440' MSL)
Keystone Ridge: -2F
10AM Sunday temperatures include:
Woodsmoke PWS: -33F (near North Pole)
Eielson AFB: -29F
Fairbanks Airport: -27F
Goldstream Creek: -27F
Cleary Summit: +2F
Little Chena Ridge +1F (south of the Steese Highway)
Gilmore Trail PWS: -1F (1440' MSL)
Keystone Ridge: -2F
Saturday, November 26, 2011
Cold in Context
Here's another view of the recent cold weather: the daily mean temperature plotted against the 1981-2010 normals; grey shading of plus/minus one standard deviation.
Here are standardized daily departures for 2011. Looked at this way, the recent cold snap was about as far from normal as the hot weather in late May. The coldest day, the 17th, with an average temperature of -35F, was 2.7 standard deviations below normal, almost the same as warmest day in, when the 28th was 2.9 standard deviations above normal. The height of cold snap was a couple days longer than the hot spell in May, but the total "excessive" (the area under the curve) will likely be somewhat greater in May than in the cold snap.
Here are standardized daily departures for 2011. Looked at this way, the recent cold snap was about as far from normal as the hot weather in late May. The coldest day, the 17th, with an average temperature of -35F, was 2.7 standard deviations below normal, almost the same as warmest day in, when the 28th was 2.9 standard deviations above normal. The height of cold snap was a couple days longer than the hot spell in May, but the total "excessive" (the area under the curve) will likely be somewhat greater in May than in the cold snap.
Friday, November 25, 2011
Thursday, November 24, 2011
Cold Persists near the Alaska Range
Unlike the Fairbanks area, clear skies have prevailed near the Alaska Range for past 36 hour. Here's the 1pm photo from Denali National Park right near the train station. The lack of clouds have allowed the cold temperatures to persist. At the Denali Park AWOS (partially visible in the photo just beyond the brown building), the high today was 20 below and low 36 below. At the DVCA2 RAWS, which is near the Wilderness Access Center and at a slightly lower in elevation than the AWOS, the high was -27F and the low -38F.
Recap of the November Cold Snap
The record setting cold snap of November 2011 is history. So, without the media hoopla, here’s what happened. It's important to emphasize that the "news" here is the early occurrence of the cold snap, rather than the absolute values of the temperatures. The exact same temperatures anytime between Thanksgiving and Valentines Day would be unexceptional.
The mean 500mb heights (30dm contours) for November 15-21 (courtesy of ESRL and NCEP/NCAR Reanalysis) show a classic pattern for cold weather in Interior Alaska, with a high over Chukotka and fairly low height northerly flow across most of mainland Alaska (I’ve added centers and arrows to indicate wind direction.
In the Fairbanks area, this was easily the coldest pre-Thanksgiving week of record. At the Airport, the lowest 7-day average temperature was -30.1F for November 15-21. The previous record was -26.5F was set November 7-13, 1989. For November as a whole, this was the third coldest event; November 24-30, 1909 and the same week in 1927 were colder.
Record lows were set at the Airport on six days (November 16th did not have a new record) and record low maximum temperatures were set November 16-19. The high temperature of -30F on the 17th is the second earliest high of -30F or lower in the winter (November 9, 1989 is the earliest). The low temperature of -41F on the 17th is the fifth earliest occurrence of -40F in the winter. Here's the plot of November record lows:
Elsewhere around the area, temperatures varied pretty much as is typical for this time of year. The average temperature for November 15-21 at the North Pole cooperative station was -37.7F, with six days with lows in the -40s and an absolute low of -49F on the 17th. At the other extreme, Keystone Ridge cooperative station, at 1600’ MSL, had an average temperature of -13.4F the same week and an absolute low of -28F on the 21st.
Most places with a long period of observations set six or seven daily records. Lowest temperatures for the cold snap include:
University Experiment Station: -41F
Eielson AFB: -41F
UAF West Ridge: -40F
As more cooperative info becomes available I'll update the extremes.
The mean 500mb heights (30dm contours) for November 15-21 (courtesy of ESRL and NCEP/NCAR Reanalysis) show a classic pattern for cold weather in Interior Alaska, with a high over Chukotka and fairly low height northerly flow across most of mainland Alaska (I’ve added centers and arrows to indicate wind direction.
In the Fairbanks area, this was easily the coldest pre-Thanksgiving week of record. At the Airport, the lowest 7-day average temperature was -30.1F for November 15-21. The previous record was -26.5F was set November 7-13, 1989. For November as a whole, this was the third coldest event; November 24-30, 1909 and the same week in 1927 were colder.
Record lows were set at the Airport on six days (November 16th did not have a new record) and record low maximum temperatures were set November 16-19. The high temperature of -30F on the 17th is the second earliest high of -30F or lower in the winter (November 9, 1989 is the earliest). The low temperature of -41F on the 17th is the fifth earliest occurrence of -40F in the winter. Here's the plot of November record lows:
Elsewhere around the area, temperatures varied pretty much as is typical for this time of year. The average temperature for November 15-21 at the North Pole cooperative station was -37.7F, with six days with lows in the -40s and an absolute low of -49F on the 17th. At the other extreme, Keystone Ridge cooperative station, at 1600’ MSL, had an average temperature of -13.4F the same week and an absolute low of -28F on the 21st.
Most places with a long period of observations set six or seven daily records. Lowest temperatures for the cold snap include:
University Experiment Station: -41F
Eielson AFB: -41F
UAF West Ridge: -40F
As more cooperative info becomes available I'll update the extremes.
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