Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
321 am akdt Wednesday Jun 3 2015
a broad upper low is centered near 73n/136w in the eastern
Beaufort Sea with a trough extending to southwest Alaska. The low
will move to near Icy Cape by Thursday afternoon...with a trough
extending southward to Bristol Bay. The low will be centered near
Cape Thompson by Friday afternoon. A southwesterly flow aloft
has set up over the central and eastern interior and will
gradually become southerly by late tonight...then continuing
a 1027 mb high centered 150 miles north of wrangel island will
move slowly southward and weaken over the chukotsk peninsula by
Thursday morning. A 1027 mb high centered near 81n/108w in the
high Arctic will weaken to a 1018 mb high centered near 80n/160w
by Friday morning. A weak thermal trough currently extends from
Kuskokwim Bay to the Susitna Valley to near Northway. The trough
will gradually intensify through Thursday afternoon...trough axis
Thursday afternoon will be on a line Dillingham-minchumina-
50 miles north of Northway. The eastern part of the thermal
trough will move northward Friday...trough axis Friday afternoon
will lie on a line Dillingham-Bettles-Old Crow-eastward into the
Current models are in generally good agreement out through
Saturday...then become increasingly divergent by Monday. By
Wednesday...both GFS and European model (ecmwf) indicate a deep polar vortex
somewhere near 80n/170w. European model (ecmwf) expands the associated circulation
to all of northern Alaska while the GFS holds on to some ridging
and warmer air aloft over the central and eastern interior.
The ensemble means keep some weak ridging over the southeast
interior...current GFS run appears to be much closer to the
ensemble mean solutions than the operational European model (ecmwf).
snow showers over most areas today...continuing tonight
over areas near the crest of the central and eastern
Brooks range. Snow could be mixed with rain in the Brooks
range in the afternoon. For Thursday...snow or snow
showers continuing near the central and Brooks range...
becoming mixed with rain in the afternoon.
rain or showers over the Alaska Range and southeast interior
today...spreading to all of the central and eastern interior
tonight. Rain shadow will develop in areas just north of the
Alaska Range Thursday and continue into Friday...with rain or
showers continuing elsewhere in the central and eastern interior.
Rain or showers will spread slowly westward into the western
interior Thursday night and Friday.
dry conditions with gusty north to northeast winds continuing
through Thursday night. Lighter winds are expected Friday.
Coastal hazard potential days 3 and 4...none
gusty north to northeast winds with minimum humidities below
30 percent are expected in zones 208-210-212-214-216-217.
Minimum humidities near or a little below 30 percent are expected
in zones 219-220. Wind gusts to 25 miles per hour or higher in zones
218-219-220 will probably be localized. Local.Minimum humidities
in zone 218 will likely remain above 30 percent. Dry conditions
and gusty winds are expected again Thursday in zones
208-210-212-214-216-217 but highest wind gust speeds Thursday may
be a bit less than those expected today. Higher humidities are
expected in the remaining zones Thursday and Friday as moisture
works its way northward and westward.
Thunderstorms...isolated wet thunderstorms expected this
afternoon and early evening in zones 223-224-225-226-227.
Thunderstorms will be extremely spotty in the southeast
interior and Alaska Range Thursday afternoon due to very marginal
instability...but will keep isolated thunderstorms in the forecast
grids. Thunderstorms are expected Thursday. For Friday...isolated
wet thunderstorms expected over most areas of the interior during
the afternoon and evening.
Alaska Range gap winds...local gusts to 25-30 miles per hour may develop
in passes this evening and continue into Friday as the thermal
trough axis moves to just north of the Alaska Range...with some
ridging along the eastern north Gulf Coast. Strongest wind gusts
will likely be in the afternoon and evening. However...minimum
humidities in passes are expected to be above 30 percent.
red flag warning for akz208-akz210-akz212-akz214-akz216-akz217-
Small Craft Advisory for pkz200-pkz215-pkz220-pkz225.
Gale Warning for pkz210.
Rf Jun 15