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Prognostic Meteorological Discussion (PMD)

Issued by National Weather Service (NWS)

                            
000
FXAK02 KWNH 211946
PMDAK 

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
346 PM EDT Sun Jul 21 2019

Valid 12Z Thu Jul 25 2019 - 12Z Mon Jul 29 2019

Models/ensembles have made a couple changes with the forecast but
overall still show a trough/ridge pattern that translates eastward
in time. Ensembles have the most stable solution over the past
36-48s hrs but some aspects of the GFS/ECMWF/Canadian were
incorporated to minimize somewhat extreme solutions in each model.
Trend has been for a quicker progression out of the central
Pacific and a more N-S stretched ridge over NW Canada that likely
pinches off an upper high in the Arctic. That combination
modulates how the Bering system (Thu) pushes through western
areas, but still likely translates into the Gulf by the weekend
and then pushes through the Panhandle around next Sunday. Timing
differences between the quicker 06/12Z GFS and slower 00Z
GFS/ECMWF average out to where the 00Z ECMWF ensemble mean lied
(and more or less the 06Z GEFS mean, albeit weaker).

Pattern supports more precipitation (and convection) to intrude
inland through the interior but not much of a break for the
Panhandle with the lead system Thu/Fri to be followed by the
Bering system Sunday. Temperatures are forecast to be within 5-10
degrees of normal for late July.


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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