Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
715 PM EDT Mon Mar 15 2021
Valid 12Z Fri Mar 19 2021 - 12Z Tue Mar 23 2021
...Overview and Guidance/Uncertainty Assessment...
Troughing in the Gulf/Panhandle region on day 4 (Friday) will give
way to a brief period of ridging before another couple of storm
systems move from the Aleutians into the Gulf this weekend and
into early next week. This results in a more amplified pattern the
second half of the period with deep troughing across the
mainland/Gulf region and ridging through much of the Bering Sea.
There remains relatively good clustering between the latest cycle
of guidance through the period, with the normal timing and
intensity differences increasing later in the period. The WPC
blend relied on majority (70 percent) operational guidance (12z
GFS/ECMWF) through day 6, increasing contributions from the
ECENS/GEFS means day 6 and 7 to mitigate late period differences.
This also maintains good continuity with the WPC CONUS progs
downstream.
...Weather/Hazards Highlights...
With the waves of low pressure approaching the southern Mainland
and the Panhandle, these areas could have periods of scattered to
widespread precipitation. A majority of the Mainland will be
mostly quiet and dry. Various systems will also bring mainly
scattered precipitation to the Aleutians, with coverage increasing
across the western islands by the end of the period as a cold
front moves into the Bering Sea. Most of the region will have
temperatures below average, especially the second half of the
period, with daytime highs averaging 10-20 degrees below normal.
Santorelli
No significant hazards are expected over Alaska during this
forecast period.
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