Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
344 PM EDT Fri Mar 15 2019
Valid 12Z Tue Mar 19 2019 - 12Z Sat Mar 23 2019
Expect periods of terrain and coastal convergence enhanced
precipitation into the southern coast of the Mainland and to
Southeast AK. Moist inflow will wrap around a series of deepened
Gulf of AK surface lows under influence of ample mid-upper level
troughing. Systems will tap an atmospheric river to produce daily
totals averaging several inches with some locally favored 5-day
totals of 10+ inches. The airmass quickly loses moisture content
farther inland, but expect modest snows from southwest AK to the
western/central Interior to northern AK as energy lifts in a
channel between a Bering Sea mean mid-upper level trough/low and
an Interior AK/western Canadian mid-upper level ridge. Relatively
dry conditions are expected to persist for much of the
east-central Interior under that ridge. Meanwhile, increasingly
stormy maritime conditions for over the Bering Sea mid-late next
week with deep surface low development. Unsettled weather should
work steadily underneath through the Aleutians toward
southwest/western AK late next week. Overall, the WPC Alaskan Days
4-8 product suite was mainly derived from the ECMWF ensemble mean
that best maintain WPC continuity, with offshore lows further
deepened considering favorable support aloft and pattern history.
Schichtel
Bullet points from the WPC Days 3-7 Hazards chart:
https://www.wpc.ncep.noaa.gov/threats/threats.php
- Heavy precipitation across portions of the Alaska Panhandle and
southern mainland Alaska, Mon-Tue, Mar 18-Mar 19.
- High winds across portions of the Alaska Panhandle and southern
mainland Alaska, Mon, Mar 18.
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