Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
509 PM EST Thu Jan 12 2023
Valid 12Z Mon Jan 16 2023 - 12Z Fri Jan 20 2023
...Overview, Guidance Assessment & Expected Impacts...
The latest guidance continues to have a fair handle on the large
scale pattern through the extended period. The flow becomes
increasingly cyclonic at most levels, except northeast AK, through
the period. This should keep breezy conditions along AK's
northern coast as well as along coastal western AK. It should
remain mild coastal southern AK and the Aleutians, with colder
conditions expected in the Interior and especially the North
Slope. Embedded cyclones will lead to wetness across south-central
and southeast AK, including the AK Panhandle. There appear to be
three main surface lows -- one moving through the southeast Bering
early, another potentially moving into the Kenai peninsula early,
and a potentially large and deep cyclone moving southeast of the
AK and Kenai Peninsulas late. Model spread isn't too large with
two of the three cyclones -- the 12z Canadian was much slower in
bringing the third into AK's vicinity and the faster GFS/slower
ECMWF generally fit in with their respective ensemble means. The
pressures, fronts, 500 hPa heights, and QPF were primarily based
on a blend of the deterministic guidance early, before shifting
away from the Canadian late and towards the 00z ECMWF/12z NAEFS
means late. This led to faster frontal progression and stronger
lows from continuity. The remainder of the grids were based on
the 19z NBM.
Roth
Hazards Highlight...
- Heavy precipitation across portions of mainland Alaska, Sun-Tue,
Jan 15-Jan 17.
- Much above normal temperatures across portions of mainland
Alaska, Sun-Tue, Jan 15-Jan 17.
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook 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