Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
605 PM EST Sun Jan 26 2020
Valid 12Z Thu Jan 30 2020 - 12Z Mon Feb 03 2020
...Well below average temperatures for most of mainland Alaska
through this week...
...Deep low pressure systems likely to bring heavy precipitation
and maritime hazards to portions of the Alaska Panhandle and the
Aleutians...
Through much the medium range period, the latest models and
ensemble guidance continues to show above average consensus on the
overall synoptic pattern. Upper level troughing should be
reinforced through next week, before gradually beginning to shift
eastward next weekend. Forecast confidence remains high for a cold
surface air mass to settle across much of Alaska well into next
week, with max and min temperatures 20+ degrees below normal for
some places. As upper level ridging moves into the western
mainland next weekend, temperatures should finally rebound back
towards normal, or possibly even above normal by early next week.
A deep low pressure system lifting north into the Gulf of Mexico
on day 4/Thursday should bring periods of widespread
precipitation, locally heavy, to parts of the southern Mainland
and much of the Panhandle. Lingering deep layered cold air could
support locally heavy snows, even into the lower elevations of
southern Alaska and the northern Panhandle. After this, weak broad
low pressure maintains across the Gulf, while another deep surface
low moves towards the western Aleutians next Saturday-Monday. The
most recent model runs have consistently shown this to be a deep
cyclone, with central pressure possibly down into the 950s mb.
Differences in placement of this low increase dramatically by day
7-8, so an ensemble approach best represents this system for now.
Expect increased rainfall chances, high winds, and maritime risks
to accompany this cyclone into early next week.
Today's WPC progs favor a majority deterministic approach through
day 5, with increasing weighting of the ensemble means beyond to
mitigate the smaller scale, less predictable, detail differences.
This maintains good continuity both with yesterday's Alaska progs
and with downstream preferences over the CONUS.
Santorelli
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