AKZ206-240000-
NORTHEASTERN BROOKS RANGE-
INCLUDING...ANAKTUVUK PASS...ATIGUN PASS...GALBRAITH LAKE... SAGWON...FRANKLIN BLUFFS
428 AM AKDT WED JUL 23 2014
...SIGNIFICANT SNOWFALL THURSDAY THROUGH FRIDAY...
SNOW WILL DEVELOP THURSDAY ABOVE 3000 FT AND LOWER TO 1000 FT THURSDAY NIGHT. SNOW WILL CONTINUE THROUGH FRIDAY. STORM TOTAL SNOW AMOUNTS OF 3 TO 6 INCHES ARE POSSIBLE WITH THE HIGHEST AMOUNTS ABOVE 3000 FT.
AKZ218-240000-
SOUTHEASTERN BROOKS RANGE-
INCLUDING...ARCTIC VILLAGE...WISEMAN...COLDFOOT... CHANDALAR D.O.T. CAMP...INIAKUK LAKE
432 AM AKDT WED JUL 23 2014
...SIGNIFICANT SNOWFALL THURSDAY EVENING THROUGH THROUGH FRIDAY FROM THE PIPELINE WEST...
FROM THE PIPELINE WEST...SNOW WILL DEVELOP THURSDAY AFTERNOON ABOVE 5000 FT AND LOWER TO 2000 FT THURSDAY NIGHT. SNOW WILL CONTINUE THROUGH FRIDAY. STORM TOTAL SNOW AMOUNTS OF 2 TO 5 INCHES ARE POSSIBLE WITH THE HIGHEST AMOUNTS ABOVE 3000 FT. THIS COULD MAKE TRAVEL DIFFICULT OVER ATIGUN PASS THURSDAY NIGHT.
Snow has already been falling in the western Brooks Range, as evidenced by the Red Dog FAA webcam photo from earlier today (elevation 962' MSL):
I took a quick look at the latest high-resolution (6km) NAM model forecast for the area, and indeed the model indicates substantial snowfall in the higher elevations over the next two days. Below is a map of the estimated total snow accumulation through Friday evening (note: the model predicts snow accumulation in liquid equivalent, and I used a 10-1 ratio to estimate total depth). I added markers for some of the FAA webcam locations, including Anaktuvuk Pass (red), Chandalar Shelf DOT (blue), Coldfoot (green), and Arctic Village (turquoise).
For historical context, here's a map that Brian put together a few days ago, showing all Alaska observing locations that have reported measurable snow accumulations in July (per GHCN data). The Brooks Range location with 2.5" is Chandalar Lake, and that event occurred on July 17, 2003.
Surely this forecast isn't normal or expected in July for those elevations and locations. I hope a reanalysis will reveal the conditions post event. Wilderness seekers in that area will get to test their resources and resolve.
ReplyDeleteWe got snowed in at Galbraith Lake in late August 1978 for a few days during a similar event. The Dehavilland Beaver on floats I was flying was iced up, and the engine refused to start at the +20's F temps. We stuck a Coleman cook stove under the engine to warm it, and washed the ice off the plane with lake water. Nothing unusual.
Gary
Gary, indeed no - not normal, although not unheard-of even if it panned out as the forecast indicated. However, the event is playing out much differently from expected, with much less precipitation now indicated for the central Brooks Range: so it seems even the short-range model forecasts were quite badly wrong. The NWS has also changed their tune accordingly. Lesson learned: in these data-sparse regions, even short-range projections can go badly awry; and the models still have a long way to go.
ReplyDeleteThe NWS folks do their job quite well. I'd be confused by too much info driven by differing outputs from multiple forecast models.
DeleteRegardless of the recent WX sources, we currently see an extensive zone of High pressure in the Bering Sea working against Lows to the SE. Consequently there's not much incentive for cold air to remain entrained over the Arctic Ocean with no extensive ridging over mainland Alaska to block the current pattern.
With ample moisture and cool advection we now have rain and snow depending upon temps and elevation. The WX pattern over Alaska will have to markedly change for different results to occur.
Now we're coming into our traditional season of moisture influx from the west and southwest, and daily decreases in insolation. That, coupled with the Tanana Valley State Fair 8/1>, guarantees inclement weather most years.
Gary