Scientific Forecaster Discussion
fxak69 pafg 201409
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
609 am akdt Thu Jun 20 2019
Synopsis...today may be the warmest day of the year so far with
high temperatures rising into the 80s for many locations. A band
of thunderstorms and showers 100nm or so east and west of a line
from Healy to Point Lay this afternoon. Stratus on the central and
eastern Arctic coast will be pulled offshore this afternoon. A
few thunderstorms and showers in the lower Yukon Delta as low
moves offshore and weakens. Thunderstorms will produce strong
gusty winds and small hail.
Models...20/00z solutions are in good agreement for short term.
They initialized well against the 19/06z surface analysis with
only minor differences in pressure and location. Solution continue
to make pretty major adjustments from run to run as they move
through the midrange and extended periods. Will use a blend of
solutions for precipitation as individually they have
precipitation spread pretty thin. Going to nudge the current
database winds again today so no big changes. Convective indicies
look pretty good in the vicinity of a line from Denali to Point
Lay with lifted indicies to -2 and cape values to 300 j/kg.
Aloft...at 500 hpa...ridging continues to build over the interior
with a 574 dam center over Livengood with ridging extending south
over the Gulf of Alaska and the northeast Pacific.Ridging also
extends north over the central Arctic. A 562 dam low remains over
the lower Yukon Delta this morning, but will slowly move northwest
offshore and weaken. A shortwave over the eastern Arctic coast
associated with a low in the Canadian archipelago will pull out to
the east this by this afternoon. A 553 dam low will move out of
the North Pacific to 300 nm south of Kodiak Island this evening. A
561 dam low over wrangel island will move north and merge with a
strong wave that will be swinging southeast across the Arctic
Friday. A 550 dam low will develop in the trough 250 nm north of
Point Barrow Friday evening. The low south of Kodiak will move
east through Saturday. The high over the interior will be cutoff
and weaken to to 568 dam by Saturday afternoon. At 850 hpa...most
temperatures over the forecast area warming to +8c to +15c by this
afternoon. The exception will be the lower Yukon Delta which will
cool Thursday to around +3c. The warmest temperatures will be
over the eastern interior extending north and west along the south
slopes of the Brooks range.
Surface...broad area of low pressure over interior Alaska. Thermal
trough has moved north and lies along the Yukon river in the upper
Yukon Flats, in the Noatak and Kobuk basins. A 1018 mb low in the
lower Yukon Delta will slowly move offshore this afternoon. A 1025
mb high will develop in Norton Sound today, then merge with high
pressure building northeast through the Bering Strait to the
Chukchi Sea. A 1020 mb thermal low will develop in the inland
Seward Peninsula, then merge with a 1019 mb thermal low that
develops in the Kobuk Basin. A 1019 mb thermal low will develop
over the western Arctic plains and move east to oliktok and merge
with the front in the Arctic.
Arctic coast and Brooks range...pretty quiet today. Some smoke
from the fire on the Seward Peninsula will move through the area,
but not impacting visibility. Thermal low in Western Plains
develops with some isolated thunderstorms and showers. A front
along the eastern Arctic coast will pull out to the east with
improving conditions today. Another front high in the Arctic will
sweep south tonight and the low in the plains will merge with it.
A strong high in the siberian Arctic will start moving southeast
with high pressure pushing over the Northwest Arctic coast.
West Coast and western interior...most thunderstorm and shower
activity will be north and east of Galena today. Isolated
activity for the remainder of the area. Warm and dry conditions
spreading over the remainder of the forecast area today with many
inland locations in the upper 70s to lower 80s.
Central and eastern interior...hot and dry. Isolated
thunderstorms and showers southwest of a line from Eagle to
Bettles. Thermal trough lies along the Yukon river in the upper
Yukon Flats today. High temperatures in the mid 70s to mid 80s
today and Friday. Lows will be in the upper 40s to mid 50s. Winds
variable to 10 mph.
Coastal hazard potential days 3 and 4...none.
Fire weather...warmer and drier across the forecast area with
decreased thunderstorms and rain shower activity the next couple
days. Isolated thunderstorms and showers south of a line from
Chicken to Nenana to Ruby in the central and eastern interior.
Isolated thunderstorms and showers in the lower Yukon Delta, and
the interior Seward Peninsula today. Thunderstorm and showers
activity Thursday will be along the thermal trough as it sets up
from Denali to Point Lay. Temperatures will warm into the 70s and
lower 80s for most inland areas with relative humidity values
falling to the 20s and lower 30s. Near red flag conditions during
the afternoon and early evening today and Thursday. Winds
generally less than 15 mph, except near thunderstorms. Relative
humidity recovery overnight will be good.
Hydrology...warmer and drier with melting level above 9000
feet the next couple days. High elevation snow melt and Glacier
melt will bring increasing flow to the streams fed by them, and
mainstem rivers like the Tanana will slowly rise over the next few