Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
649 PM EDT Mon Jun 08 2020
Valid 12Z Fri Jun 12 2020 - 12Z Tue Jun 16 2020
...Overview and Weather Highlights/Threats...
A relatively progressive flow pattern is expected to persist
across the North Pacific and into the Gulf of Alaska through the
extended forecast period, while weak and broad upper ridging
persists from the Arctic Ocean into western Canada. By the weekend
into early next week, upper ridging should expand further, with
heights expected to gradually rise across mainland Alaska. through
late this week, the Interior of Alaska will lie within a region of
chaotic and relatively weak flow. This regime will keep isolated
to scattered showers and thunderstorms a possibility, more
widespread in higher terrain of the Alaska and Brooks Ranges,
through the weekend. The Aleutians will see a couple potential
rounds of precipitation and gusty winds, the first Fri-Sat as one
low pressure system passes across/near the island chain, and
another by next Mon-Tue. Temperatures in this pattern are expected
to be above average through the forecast period, with highs
ranging from 5 to 15 deg F above average for many areas,
especially across western mainland Alaska. Temperatures across the
Interior may begin to warm further by early next week as upper
ridging begins to expand across mainland Alaska.
...Guidance/Predictability Assessment...
A blend of the 12Z ECMWF/GFS was used during days 4-5 (Fri-Sat),
with majority weight placed on ECENS/GEFS ensemble means from day
6 (Sun) onward. Model/ensemble consensus has improved
substantially during the extended forecast period over the pasts
couple days, and spread does not really begin to increase
substantially until the end of the forecast period. Therefore,
forecast confidence was at least slightly above average during
days 4-7, and average (considering the time frame) on day 8.
Ryan
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
- Much above normal temperatures across portions of mainland
Alaska, Thu-Sun, Jun 11-Jun 14.
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html