Thunder at Barrow

Image Courtesy of the FAA

A line of thunderstorms popped up just east of Barrow late Sunday afternoon.At the National Weather Service Office in Barrow, a few rumbles of thunder were heard, though there was no rain at Barrow from these cells. The Alaska Fire Service's lightning detection network recorded a couple of strikes just southeast Dease Inlet. This image from the FAA at 516pm AST (with a very dirty lens) shows something of the cells.

Cool July

Here's an update on temperature variation thus far in 2012, this time using Keystone Ridge data. Since late June temperatures have been consistently, though not exclusively, below normal. This is somewhat unusual because it also as been dry. Sustained cool weather in mid-summer typically occurs with stratiform rain. However, since June 1st rainfall here on the ridge is only at 55% of normal.

Frost on the Pumpkin

Ester Dome webcam courtesy of the FAA

Clear skies and a cool airmass allowed temperatures to drop to unusually low levels this morning, which a freeze in some of the lowest valley spots. To the right was the 4am view from Ester Dome.

Updated:
Low temperatures included:

Goldstream Creek: 30F
Chena Hot Springs: 32F
Woodsmoke: 32F
Chatanika: 34F
Eielson AFB: 37F
Nenana: 37F
North Pole: 39F
UAF West Ridge: 40F
Keystone Ridge: 41F
Aurora: 41F
Fort Wainwright: 42F
Fairbanks Airport: 44F

Alaska Sea Ice

MODIS-Terra image courtesy of the University of Alaska

I've been waiting for a good clear sky MODIS image to see the extent of sea ice off the North Slope, and here it is. This image is from 2pm ADT Thursday, and practically all that blue-white area north of the coast is sea ice. The ice edge is still south of 71N in the Chukchi Sea, but notice the large holes in the ice northwest of Barrow, north of 72N. Look for a rapid retreat of the ice edge over the next couple weeks as these holes grow and coalesce.

Courtesy UAF Sea Ice group

Left is the view Thursday afternoon (almost exactly the same time as the MODIS image) from Barrow, looking north-northwest. A real chamber of commerce day. 

Cool Morning

Temperatures dropped in the 30s and 40s overnight in Fairbanks-land as the airmass dried out a bit. Low temperatures included:

Goldstream Creek: 35F
Chena Hot Springs: 35F
Chatanika: 39F
Eielson AFB: 41F
UAF West Ridge: 44F
Keystone Ridge: 44F
Fairbanks Airport: 47F

Tanana River is Up

The combination of high level snow melt and persistent rains the past week in the upper Tanana Valley have pushed the Tanana River up toward problem levels in the Fairbanks area. The hydrograph ending at 8am Wednesday morning shows the stage is now up to 23.6 feet at at Fairbanks. This level does not produce flooding per se but with the river running near bankful, bank erosion greatly increases, some water may start flowing into Piledriver Slough, and if it stays up this high for a couple days, groundwater may surface in the Perkins Landing area.

See-Saw Temperatures

Here's a a simple plot of the standardized monthly temperature anomalies at Fairbanks for the past 11 months. Recall the "standardized" is in effect scaling the absolute departures by the typical spread of monthly temperatures (technically, departure divided by standard deviation). The see-saw pattern that started in October continues.

June Summary for Fairbanks

From my colleague Corey… 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
343 PM AKDT SUN JUL 1 2012

...JUNE WEATHER SUMMARY FOR FAIRBANKS...

THE AVERAGE TEMPERATURE OF 61.6 DEGREES WAS 1.2 DEGREES ABOVE
NORMAL. IT JUST BARELY CONTINUED THE TREND OF ALTERNATING COLD AND
WARM MONTHS AT FAIRBANKS THAT DATES BACK TO OCTOBER 2011. FOR THE
MONTH...THE AVERAGE HIGH TEMPERATURE AT THE AIRPORT WAS 72 DEGREES
AND THE AVERAGE LOW 51. THE HIGH TEMPERATURE FOR THE MONTH OF 86
DEGREES WAS OBSERVED ON THE 23RD AND THE LOW FOR THE MONTH OF 43
OCCURRED ON THE 13TH. NONE OF THE OBSERVATION SITES IN THE AREA
HAD FREEZING TEMPERATURES. EVEN KJNP IN NORTH POLE WHICH ON MANY
YEARS WILL HAVE A SPRING FREEZE IN EARLY OR MID JUNE HAD A MONTHLY
LOW OF 41 DEGREES...THE WARMEST ON RECORD SINCE 1969.

TEMPERATURES MUCH OF THE MONTH WERE NEAR TO ABOVE NORMAL...BUT
THERE WERE A COUPLE OF PERIODS AROUND MID MONTH AND TOWARD THE END
OF THE MONTH WITH BELOW NORMAL TEMPERATURES. THERE WERE 4 DAYS
WITH A HIGH TEMPERATURE OF 80 DEGREES OR ABOVE...JUST ONE SHY OF
THE JUNE AVERAGE. THERE WERE THREE CONSECUTIVE DAYS WITH A HIGH
TEMPERATURE OF 80 DEGREES OR WARMER FROM THE 22ND THROUGH THE
24TH...WITH A PEAK TEMPERATURE OF 86 DEGREES ON THE 23RD. THE
HIGH OF 86 WAS THE WARMEST TEMPERATURE OBSERVED AT THE AIRPORT
IN NEARLY A YEAR SINCE A HIGH OF 88 DEGREES ON JUNE 25TH 2011.

RAINFALL WAS FREQUENT...BUT MOSTLY ON THE LIGHT SIDE. THERE WERE A
TOTAL OF 14 DAYS WITH MEASURABLE PRECIPITATION AT THE AIRPORT...3
MORE THAN NORMAL FOR JUNE. THE HEAVIEST PRECIPITATION OCCURRED ON
THE 26TH WHEN A STEADY RAIN FELL AT THE AIRPORT FROM THE LATE
MORNING INTO THE EARLY EVENING AND PRODUCED 44 HUNDREDTHS OF AN
INCH OF RAIN. FOR THE MONTH...A TOTAL OF 1.39 INCHES OF RAIN WAS
OBSERVED WHICH WAS JUST 2 HUNDREDTHS OF AN INCH ABOVE NORMAL.
RAINFALL ON THE HILLS WAS NOT MUCH HIGHER AT KEYSTONE RIDGE WITH A
TOTAL OF 1.66 INCHES FOR THE MONTH. EAST OF FAIRBANKS...EIELSON
AIR FORCE BASE OBSERVED SIGNIFICANTLY MORE RAIN WITH A TOTAL OF
2.57 INCHES.

AREA RIVERS MOSTLY FELL DURING THE MONTH OF JUNE. THE CHENA RIVER
STARTED THE MONTH ON THE HIGH SIDE BUT FELL THROUGHOUT THE MONTH
AND WAS AT LOW LEVELS AT THE END OF THE MONTH. SNOW AND ICE MELT
IN THE ALASKA RANGE COMBINED WITH RAINFALL IN THE UPPER TANANA
BASIN TO CAUSE THE TANANA RIVER AT FAIRBANKS TO RISE SIGNIFICANTLY
DURING THE FIRST TWO WEEKS OF THE MONTH...AND FROM THE 10TH TO THE
15TH LEVELS WERE AT OR NEAR RECORD DAILY DISCHARGE VALUES AT
FAIRBANKS. THE TANANA THEN FELL FOR SEVERAL DAYS BEFORE SLOWLY
RISING DUE TO RAINFALL AT THE END OF THE MONTH. NO FLOODING WAS
REPORTED ON ANY AREA RIVERS DURING THE MONTH OF JUNE.

THE FIRE SEASON STARTED TO PICK UP LATE IN THE MONTH AFTER A
PERIOD OF WARM AND DRY WEATHER...BUT FREQUENT SHOWERS DURING THE
LAST WEEK OF THE MONTH PUT THE BREAKS ON THE FIRE SEASON. AT THE
END OF JUNE...A TOTAL OF 144,222 ACRES HAD BURNED STATEWIDE...WHICH
IS FAR BELOW NORMAL AND ALSO WELL SHORT OF LAST YEAR.

LOOKING AHEAD TO JULY...NORMAL HIGH TEMPERATURES PEAK OUT DURING
THE FIRST HALF OF THE MONTH AT 74 DEGREES AND THEN SLOWLY FALL TO
70 ON THE 31ST. NORMAL LOW TEMPERATURES ARE IN THE LOW 50S ALL
MONTH. JULY IS TYPICALLY THE WETTEST MONTH OF THE YEAR WITH AN
AVERAGE MONTHLY RAINFALL OF 2.16 INCHES. OVER THE
YEARS...RAINFALL HAS VARIED SIGNIFICANTLY DURING THE MONTH OF
JULY WITH THE RECORD DRIEST AND WETTEST JULY`S IN THE PAST TEN
YEARS. IN 2009 ONLY 6 HUNDREDTHS OF AN INCH OF RAIN WAS
OBSERVED...AND IN 2003 A RECORD 5.96 INCHES OF RAINFALL WAS
OBSERVED. TYPICALLY THERE ARE 3 DAYS DURING THE MONTH WHEN A
THUNDERSTORM IS OBSERVED AT THE AIRPORT...BUT IN MOST YEARS THERE
ARE MANY MORE DAYS WITH THUNDERSTORMS OVER THE HILLS TO THE NORTH
AND EAST OF TOWN.

THE SUN REMAINS VISIBLE ABOVE THE HORIZON PAST MIDNIGHT DURING THE
FIRST TWO WEEKS OF THE MONTH...AND THERE CONTINUES TO BE 24 HOURS
OF USABLE DAYLIGHT UNTIL THE 27TH AT WHICH POINT THERE IS NO
LONGER 24 HOURS OF CIVIL DAYLIGHT. SOME OF THE BRIGHTEST STARS
WILL BRIEFLY BECOME VISIBLE AGAIN BY THE LAST WEEK OF THE MONTH.

THE FORECAST FOR JULY FROM THE CLIMATE PREDICTION CENTER INDICATES
THAT THERE ARE NO STRONG CLIMATE SIGNALS THAT WOULD TILT THE ODDS
IN FAVOR OF AN UNUSUALLY WARM OR COOL JULY...AND THERE ARE ALSO NO
STRONG CLIMATE SIGNALS THAT POINT TOWARD AN UNUSUALLY DRY OR WET
JULY.