Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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391 FXAK02 KWNH 012110 PMDAK Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 510 PM EDT Sat Jun 01 2024 Valid 12Z Wed Jun 05 2024 - 12Z Sun Jun 09 2024 ...Southern Mainland/Interior to Southeast Alaska Heavy Precipitation Threat into next Midweek... ...Guidance Evaluation and Preferences... Prefer a composite of reasonably clustered 12 UTC GFS/ECMWF/Canadian models Wednesday into Friday in a pattern with slightly above average predictability and identified/collaborated weather threats. Opted to switch preference to best compatible GEFS/ECMWF ensemble means onward through next weekend with less predictable flow details amid growing forecast spread and individual system uncertainties. ...Weather/Hazards Highlights... A dynamic/closed upper low tracking to the south of Alaska will lift into the eastern/northern Gulf of Alaska into Wednesday. This will support a deepened surface low/system in the Gulf of Alaska and a period of heavy precipitation and lingering enhanced winds into Southeast Alaska given some enhanced ex-tropical moisture influx. Easterly wrapping flow and impulses offer an additional threat of heavy precipitation into eastern SouthCentral/Alaska Range along with some enhanced rains into the Interior next week. Meanwhile, an upper low in the Arctic Ocean to the northwest of the state looks to send upper low/trough energy southward into the Bering Sea/West Coast and southeastward through the Aleutians where there is growing support for a deepened upper low/surface lows later next week, while several weaker shortwaves traverse the southern side of this mean troughing south of the Aleutians and towards the Gulf. Over the Mainland itself, upper ridging should build warming. Schichtel Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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 $$