Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
540 PM EDT Mon Mar 16 2020
Valid 12Z Fri Mar 20 2020 - 12Z Tue Mar 24 2020
...Overview and Guidance/Predictability Assessment...
A threat of organized wintry weather/enhanced winds associated
with a series of progressive/dynamic lows will lift through an
unsettled Bering Sea/Strait and for periods work inland into the
Interior/North Slope/Arctic Ocean. This will include development
of a particularly deep Bering Sea storm Thursday into Friday that
offers well organized frontal structures that will in particular
focus winds and precipitation. This low will gradually fill and
lift poleward later week in the wake of an exiting lead Arctic
Ocean system. Several more systems will then train across the
region in this recurring pattern, but predictability is lower for
these more modest low/precipitation threats. Expect moderate
temperatures over the Interior/North Slope this week, but remain
cold enough to support periods of heavy snow, with a particular
risk for northwest Alaska. Meanwhile underneath, additional but
weaker system trough/jet energies will dig through the Gulf of
Alaska in a pattern with modest precipitation potential for
southern/southeast Alaska.
...Weather Highlights/Threats...
The WPC Alaskan medium range product suite valid Friday into
Sunday was mainly derived from a composite blend of the 12 UTC
GFS/ECMWF/UKMET/Canadian. Embedded system forecast spread is a bit
messy during this period at smaller scales, but overall these
models offer a similar system pattern. Transitioned to the more
compatable 12 UTC GEFS/NAEFS/ECMWF ensemble means into early next
week amid growing model spread. This methodology tends to mitigate
less predictable small scale variance days 4-8 and maintains good
WPC forecast continuity.
Schichtel
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:
- Heavy snow across portions of western Alaska, Thu-Fri, Mar
19-Mar 20 and Sun, Mar 22.
- Heavy snow across portions of southwestern mainland Alaska,
Fri-Sat, Mar 20-Mar 21.
- High winds across portions of mainland Alaska, Thu-Fri, Mar
19-Mar 20 and Sun, Mar 22.
- Much above normal temperatures across much of northwestern to
northern Alaska, Thu-Mon, Mar 19-Mar 23.
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