Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
624 PM EDT Sun Mar 15 2020
Valid 12Z Thu Mar 19 2020 - 12Z Mon Mar 23 2020
...Overview and Guidance/Predictability Assessment...
A protracted series of dynamic lows will lift through a highly
unsettled Aleutians and Bering Sea and tend to work along with
precipitation/weather inland into the Interior/North Slope then
Arctic Ocean. This will include development of a particularly deep
Bering Sea storm Thursday that offers well organized frontal
structures that will focus winds and widespread and
enhanced/widespread precipitation. This low will gradually fill
and lift poleward later week in the wake of an exiting lead Arctic
Ocean system, but will remain a significant focus for weather.
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 break eastward through the Gulf of
Alaska in a pattern with more modest precipitation potential for
southern and southeast Alaska.
...Weather Highlights/Threats...
The WPC Alaskan medium range product suite valid Thu-Fri was
derived from a composite blend of reasonably well clustered
guidance from the 12 UTC GFS/ECMWF/UKMET/Canadian. Transitioned to
the compatable 12 UTC GEFS/NAEFS/ECMWF ensemble means over next
weekend amid steadily growing model spread. This methodology tends
to mitigate less predictable small scale variance. Forecast
continuity and predictability overall seems above normal.
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
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