Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
322 PM EDT Fri Nov 01 2019
Valid 12Z Tue Nov 05 2019 - 12Z Sat Nov 09 2019
Upper ridging over the Gulf, western Aleutians, and northeastern
Russia will consolidate toward the Bering Strait midweek next
week, favoring troughing to its southwest and south. The
models/ensembles were in good agreement through the period on the
longwave pattern but differed in the smaller wavelength features,
including Tue/Wed around Bristol Bay. There, consensus has shifted
toward allowing some mid-level vorticity to pinch off to the
southwest into the in-situ upper low south of the AkPen, tugging
at the system a bit. Overall, there was still little change to the
surface fronts from 24 hrs ago. A varying multi-model/ensemble
blend among (mostly) the 12Z GFS/00Z ECMWF and the 06Z GEFS
mean/00Z ECMWF ensemble mean was used as a starting point.
Preferred to rely mostly on the ensembles for next Thu-Sat with
the evolution of the complex/multi-frontal system south of the
Aleutians/Southcentral given the low predictability. Up to that
point, deterministic models showed the chance of a coherent
surface low moving toward the coast (Kodiak to Kenai) as the front
weakens. How quickly this may happen is still a question. By the
end of the period, upper pattern preference suggests a slower but
steady movement of the system in the Pacific toward the
Gulf/Panhandle with high pressure over most of the interior.
Rain/snow should mostly be confined to coastal and near-inland
areas from the Aleutians and across Kodiak Island, attempting to
move into the Panhandle by next Fri and more likely by Saturday.
Temperatures will remain near to above average over much of the
state, especially the North Slope, with the exception over the
Panhandle. High pressure (higher than 1040mb) will slide
southeastward through the Yukon and funnel cooler temperatures
through the region on easterly flow.
Fracasso
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