Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
158 PM EDT Tue Jun 11 2019
Valid 12Z Sat Jun 15 2019 - 12Z Wed Jun 19 2019
...Guidance/Predictability Assessment...
Todays WPC Alaskan medium range product suite was primarily
derived from a blend of the 12 UTC GFS/GEFS mean, 00 UTC
ECMWF/ECMWF ensemble mean, and the National Blend of Models.
Applied greater blend weightings to the deterministic models day
4/5 to provide detail consistent with above normal predictability.
Forecast spread remains manageable, but gradually increases
through later period. This supports increasing ensemble weightings
day 6-8 in a pattern with closer to average uncertainty. This
solution maintains good WPC forecast continuity.
...Pattern Overview and Weather/Threats Highlights...
It remains the case that recent models/ensembles have been in
general agreement in principle with a slow pattern evolution. Two
slowly moving upper lows to the north and south of the mainland
favor weak ridging with generally warm and benign weather over the
interior through this forecast period.
In this pattern, a closed mean trough will lift over the Arctic to
the northeast of the state and force settlement of a
trailing/cooling front down over the North Slope. Well underneath,
slow moving closed low/trough energies shift from south of the
eastern Aleutians/Alaskan Peninsula toward Kodiac Island and the
northern Gulf of Alaska days 4-8. Precipitation/windy/unsettled
conditions are expected to spread across the region and downstream
into the Alaskan southern tier. This system will also offer a
prolonged maritime hazard.
Schichtel
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
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