Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
509 PM EDT Wed May 06 2020
Valid 12Z Sun May 10 2020 - 12Z Thu May 14 2020
...Guidance/Predictability Assessment and Weather/Hazard
Highlights...
A deep storm over the western Bering Sea Sat will slowly fill
Sun/Mon. Tight pressure gradients around the low will ease, but
still offer some threat of high winds/seas. A developing
low/frontal system will threaten the Aleutians and southern Bering
Sea by Tue/Wed, digging to the western/southern Gulf of AK next
midweek. This storm should be well organized, but not as deep.
Upper ridging will meanwhile rise and persist over much of
mainland AK. Temperatures will become upwards of 20 degrees above
average across parts of mainland AK through the period, with
temperatures forecast to rise into the 60s and 70s for portions of
the Interior. Underneath, low energies held down over the Gulf of
Alaska and northeast Pacific should offer limited influence on AK
weather next week, but flow may support periodic rainfall into the
southern Alaskan tier.
The 12 UTC GFS/ECMWF/Canadian seem most in line with GEFS/ECMWF
ensemble means and a composite along with the 19 UTC National
Blend of Models (NBM) was adopted Sun/Mon. This solution offers
system detail consistent with a pattern with above normal
predictability. Transitioned to just GEFS/ECMWF ensembles and the
NBM by days 7/8 amid growing forecast spread in a pattern with
closer to average predictability. WPC continuity was well
maintained for this amplified pattern.
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:
- Much above normal temperatures across portions of mainland
Alaska, Sat-Wed, May 9-May 13.
- Much above normal temperatures across portions of the Alaska
Panhandle, Sat-Mon, May 9-May 11.
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