Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
355 PM EDT Thu Sep 5 2019
Valid 12Z Mon Sep 9 2019 - 12Z Fri Sep 13 2019
The forecast period begins on Monday with a broad trough over the
Bering Sea and Aleutians, and a Rex block over western Canada with
an upper level high over the Northwest Territories and a broad low
over British Columbia. By midweek, the Bering Sea trough emerges
as a low over the Gulf of Alaska, and a more powerful low pressure
system emerges over the Bering Sea that lingers through the end of
the week. The 00Z ECMWF was faster than the model consensus with
both of these low pressure systems, and also well displaced from
the EC mean. There was better agreement among the operational 00Z
CMC, 12Z GFS, and the ensemble means, so a blend of those
solutions served as a good starting point in the forecast process,
along with less of the 00Z ECMWF.
In terms of sensible weather, this equates to a rather active
weather pattern for the maritime regions and coastal areas of the
state, especially the Aleutians and the southern coast of Alaska.
Increased moisture advection north of the Gulf low is expected to
produce moderate to locally heavy rainfall from King Salmon to the
southern Yukon border, including the Anchorage area. Gale force
winds are likely across parts of the Aleutians and especially over
the Bering sea for the middle to end of the week in association
with the big surface low. Temperatures are expected to be mainly
in the mid 50s to upper 60s for highs, and mid 30s to near 50
degrees for overnight lows.
Hamrick
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Hazards:
- Heavy rain across portions of mainland Alaska, Wed-Thu, Sep
11-Sep 12.
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
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