Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
427 PM EDT Wed Jun 26 2019
Valid 12Z Sun Jun 30 2019 - 12Z Thu Jul 04 2019
The WPC Alaskan medium range product suite was primarily derived
from a composite blend of the 12 UTC GFS/GEFS and 00 UTC
ECMWF/ECMWF Ensemble mean guidance along with the 12 UTC National
Blend of Models. Model and ensemble forecast spread has decreased
since yesterday, bolstering forecast confidence to above normal
levels days 4-8. This maintains excellent WPC continuity.
Model guidance continues to agree that the northern extent of the
upper ridge over the Interior/North Slope will breakdown through
the medium range period, allowing for portions of the mainland to
be influenced by a stronger and more active westerly
mid/upper-level flow. There is a decent guidance signal for a
series of weakening frontal systems across the Aleutians and into
western portions of the mainland; whose associated shortwaves
knock down the ridge, with associated moisture and precipitation
working into a lead summertime airmass. A deeper second main
system brews back across the Aleutians and Bering Sea before
reaching the mainland in about a week with stronger flow. This may
also offer a maritime and eventual precipitation/wind threat.
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
Hazards:
- Excessive heat risk across portions of Mainland Alaska, Sat-Sun,
Jun 29-Jun 30.
- Enhanced wildfire risk across portions of Mainland Alaska,
Sat-Wed, Jun 29-Jul 3
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