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Prognostic Meteorological Discussion (PMD)

Issued by National Weather Service (NWS)

                            
000
FXAK02 KWNH 251923
PMDAK 

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
322 PM EDT Sun Aug 25 2019

Valid 12Z Thu Aug 29 2019 - 12Z Mon Sep 02 2019

Upper troughing will settle into the Bering Sea and eventually
western Alaska next week. The upper low in the Arctic will
continue to pull away back toward the North Pole which will allow
for WSW flow this weekend rather than NW flow across the North
Slope and northeastern Alaska (warming trend in temperatures).
Over the Panhandle, a drier period is in store with weak ridging.

Models/ensembles were in decent agreement on the synoptic scale
but differed on system timing/evolution late this week through the
weekend. Focus will be on how the tail end of the lead Bering
system Thu lifts into the eastern Aleutians this weekend.
Deterministic models have been a bit quicker than the ensemble
means with the developing wave around Friday that may lift across
the island chain but have wavered on how deep this may be. Split
between the 12Z GFS and 00Z ECMWF seemed to be reasonable given
the inconsistencies which takes a modest system in the
positively-tilted trough setup toward Bristol Bay and eventually
the Gulf. This would bring increased rain chances for Southcentral
next week after a lighter bout of rain with the lead dying
occlusion Friday.

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

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

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