Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
233 PM EDT Tue Jul 16 2019
Valid 12Z Sat Jul 20 2019 - 12Z Wed Jul 24 2019
Flat flow aloft will transition into a more amplified pattern with
time across northeast Asia, the northeastern-most Pacific, and
Alaska. Despite this, the guidance shows moderate spread through
the period. On Friday night, the 00z Canadian and 00z ECMWF were
closest to the ensemble mean solutions, so they were initially
given more weight with the system crossing Alaska Friday night
through Saturday. Thereafter, the 00z Canadian becomes an outlier
and was scrapped. The 00z ECMWF is on the quick side of the
guidance with another system moving through the Bering Sea early
next week, while the 12z GFS is closest to the ensemble means.
Thought the best course of action was a more Canadian/ECMWF heavy
blend (along with the 00z ECMWF mean and 00z NAEFS mean) early on
before shifting more in the direction of the 12z GFS/ensemble
means early next week. While this led to modest changes in
frontal position (northward) and weak waves moving through AK
early on, it converged upon continuity with time. Confidence is
below average in the forecast by next Tuesday.
Mild to warm temperatures are forecast for the state this period
-- temperatures remain on pace for record warmth for the month of
July across south-central AK. Northern and southeastern
AK/panhandle appear wettest this period as disturbances move
through the Westerlies bringing occasionally moderate
precipitation.
Roth
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