Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
349 PM EDT Wed Apr 17 2019
Valid 12Z Sun Apr 21 2019 - 12Z Thu Apr 25 2019
...Guidance/Predictability Assessment and Weather
GEFS/ECMWF ensembles seem reasonably compatable days 4-8. The 00
UTC ECMWF seemed to be the best clustered model with these
ensemble systems. The WPC Alaskan product suite was primarily
derived from a composite blend of these guidance pieces along with
the National Blend of Models as appropriate. This maintained good
WPC continuity. However, newer 12 UTC GFS/ECMWF runs offer
increased system variance, lending renewed caution with small-mid
scale system aspects. That said, there is decent confidence the
pattern over the next week will be highlighted by a deepened and
meandering storm/low set to spin heavy winds/high seas and heavy
precipitation next week over the northern Gulf of Alaska and
southern Alaska, especially in favored terrain. There may also be
additional coastal focus into southeastern Alaska with potential
triple point developments. This will overall be supported by
amplified mean closed low/troughing aloft, with periodic upstream
reinforcement from upper trough energies digging down over
unsettled western/southwest Alaska and the Bering Sea.
Bullet points from the WPC Days 3-7 Hazards chart can be found at:
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Sat-Mon, Apr 20-Apr 22.
- Heavy precipitation across portions of the Alaska Panhandle,
Tue-Wed, Apr 23-Apr 24.
- High winds across portions of the Alaska Panhandle and mainland
Alaska, Sat-Sun, Apr 20-Apr 21.
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be