282
FXAK02 KWNH 262354
PMDAK

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
753 PM EDT Wed Jun 26 2024

Valid 12Z Sun Jun 30 2024 - 12Z Thu Jul 04 2024

...Overview and Guidance Evaluation/Preferences...

The ensemble means from the GEFS, EC, and CMC remain in good to
excellent agreement on the evolution of the upper-air pattern
across Alaska through the medium-range period.  In this Rex Block
configuration, an upper ridge will have a tendency to close off
across the northern half of Alaska while an initially deep Bering
Sea low weakens and slides under the ridge across the Gulf of
Alaska through the middle of next week.  The models have generally
trended slower with the eastward motion of this low since
yesterday.  The deterministic solutions are even slower than the
ensemble means.

The WPC medium-range grids for Alaska was based on a general model
compromise of 40% from the 12Z GFS and GEFS, 40% from the 00Z EC
means and 12Z ECMWF, and 20% from the 12Z CMC and CMC mean.


...Weather/Hazards Highlights...

This pattern will favor the Aleutians and AK Peninsula to be
rainy, as the lingering Bering Sea cyclone gradually slides across
the Aleutians reaching into the Gulf of Alaska by early next week.
 The double-barrel system will allow for modest rainfall in its
vicinity.  Winds should generally peak in the 30 kt (35 mph) range
at times across the Arctic Coast and coastal areas.  The terrain
in south-central and northern AK are expected to have the best
chance of showers and thunderstorms. There is the possibility of
dry lightning strikes during the afternoons and evenings which
would increase the risk for fire weather concerns given the dry
fuels across the region.  Ridging across the Mainland will
maintain warm to hot temperatures.  Afternoon maximums should lie
the 80-90F range for the most part across the eastern interior
sections.  Highs mostly in the 60s and 70s are expected across
lower elevations of south-central AK, with mainly 50s and 60s in
most coastal areas, 50s and 40s across the North Slope, and mid to
upper 40s in the Aleutians.  Higher elevations in the terrain
across south-central and southeast AK should fall below freezing
overnight.  The North Slope will be cool overnight with lows in
the 30s, while highs will approach 60 degrees not too far inland
from the shore, and perhaps to near 80 degrees farther inland over
the central portion of the North Slope on Saturday.  These
temperatures would qualify for Hazardous Heat.  The ongoing
computer network issues have continued to prevent the creation of
the Hazards map again today.  Thereafter, a surface high pressure
system gradually sliding from west to east off the northern
coastline of Alaska will funnel colder air from the Arctic Ocean
into the North Slope.

Kong/Roth


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

$$