Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
538 PM EDT Thu Oct 15 2020
Valid 12Z Mon Oct 19 2020 - 12Z Fri Oct 23 2020
...Guidance/Predictability Assessment...
Upper ridging is forecast to move into interior Alaska from the
west by midweek next week, blocking much of the state from
significant precipitation. The 12Z guidance showed good agreement
overall to start the period Mon-Tue and a deterministic blend
sufficed. Thereafter, the 12Z GFS strayed from the 12Z
ECMWF/Canadian and ensemble mean consensus with its farther north
solution nearing the AKPen/Kodiak next week. This may stem from an
earlier focus on a system across the Pacific where the other
models develop a trailing system. With the uncertainty in the
smaller/embedded systems, opted to rely on the larger cluster of
solutions near the 12Z ECMWF. This would mean increased but a bit
slower upper ridging into western areas next Wed-Thu, perhaps into
Fri, favoring any system to stay just to the south of the area
except for the Aleutians.
...Weather/Threats Highlights..
Upper ridging will bring above normal temperatures to much of the
Interior, especially over the North Slope. There, temperatures may
be 15-20 degrees above normal (upper 20s to low 30s). Areas of
southeastern Alaska and especially the Panhandle will see near to
below normal temperatures (perhaps by 10-20F) as high pressure
delivers easterly flow to the region. Rainfall will be confined to
the Aleutians and coastal Southcentral areas, as well as into the
Panhandle early in the week as lingering surface low pressure
weakens.
Fracasso
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:
No significant hazards are expected over Alaska during this
forecast period.
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