Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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766 FXAK02 KWNH 042231 PMDAK Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 631 PM EDT Thu Jul 04 2024 Valid 12Z Mon Jul 08 2024 - 12Z Fri Jul 12 2024 ...Overview and Guidance Evaluation/Preferences... Model and ensemble guidance seems reasonably clustered valid on Monday-Wednesday in an amplified and slowly evolving pattern with above average predictability for broad mass fields, albeit with more varied local QPF focus. Prefer a 12 UTC GFS/ECMWF/UKMET/Canadian composite for system detail. Opted to switch to best compatible GFS/ECMWF and GEFS/ECMWF ensemble means for next Thursday/Friday amid gradually growing forecast spread. WPC product continuity is best maintained in this manner. ...Weather/Hazards Highlights... A wavy and slowly set to weaken surface front settling generally west to east and then settling across Mainland Alaska should provide focus for some moderate to locally heavier precipitation, with higher totals likely associated with higher terrain given favorable upper support this weekend into next week. Much of Alaska remains generally wet and unsettled overall the entire period, which should help bring some relief to the spreading wildfires across the state currently. By this weekend into early next week, rain and storms will increase in coverage and intensity from Southwest Alaska through the Alaska Peninsula to Southern Coast as Gulf moisture gets pulled northward ahead of northern stream upper troughs/systems progression over the mainland. A main heavy rainfall/runoff issue threat may be from Southwest Alaska to especially favored south facing terrain of the Alaska Range Sunday and Monday. Given overall upper troughing over the state into next week, daytime highs across nearly all of Mainland Alaska will be well below normal, with the greatest anomalies across western and northern parts of the state. Temperatures may begin to moderate again by mid next week. By then there is also a still growing guidance signal to lift an organized low pressure/frontal system up across the Gulf of Alaska. This slow/evolving track would provide protracted unsettled maritimes conditions over the Gulf and act to increasingly next week support potential for some moderate to heavy rainfall from southern Alaska through the Southeast. The main focus may develop from eastern southern Alaska through northern Southeast Alaska next Tuesday and Wednesday. 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 $$