Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
339 PM EDT Thu Oct 31 2019
Valid 12Z Mon Nov 04 2019 - 12Z Fri Nov 08 2019
Upper ridging over the Gulf, western Aleutians, and northeastern
Russia/Bering Strait will consolidate into northwestern Alaska
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. A varying multi-model/ensemble blend among the 12Z
GFS/00Z ECMWF and the 06Z GEFS mean/00Z ECMWF ensemble mean was
used as a starting point. 00Z ECMWF was not preferred for Tue-Wed
as it seemed too aggressive with a small upper low moving through
the interior where the majority suggests fervent ridging. 12Z GFS
was weaker and preferred. By next Thu/Fri, GFS appeared too
progressive and too far south with the elongated occluded system
south of the Gulf. Favored the 00Z ECMWF here and across the
mainland as the lead-in feature moved out of the region. ECMWF
ensemble mean was preferred over the GEFS mean for its better
definition.
On Monday, system south of the central Aleutians will spread
rain/snow over the Aleutians into southwestern Alaska before
sliding eastward across Southcentral. In the western Bering, a
system will pass through the western Aleutians late Tuesday and
track southeastward as its triple point takes over and reforms
south of the AkPen. This will limit rain/snow to mainly coastal
and near-inland areas from the Aleutians and across Kodiak Island,
attempting to move northward by next Fri, depending on the
strength of the ridging to its northeast.
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 NW Territories of Canada 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