Scientific Forecaster Discussion

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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska
320 PM akdt Tuesday Apr 15 2014

aloft at 500 mb...a closed low pressure system Over Point lay
continues to move northeast along the Chukchi Sea coast and is
expected to be slightly northeast of Barrow by Wednesday
morning. The high pressure ridge then closes off over the Chukchi
Sea just west of Point Hope and meanders around the area through
Friday. The GFS and European model (ecmwf) models then begin to diverge in how
this high pressure is handled beyond Friday with GFS keeping it
in place and European model (ecmwf) building high pressure across the interior and
North Slope. Overall leaning towards the European model (ecmwf) high pressure ridge
in the extended.

At the surface...a 988 mb low in the southern Bering Sea will
move southeast to be located 150 nm northeast of Dutch Harbor but
weaken to 994 mb by afternoon. This low will continue to weaken
and then redevelop over the Bristol Bay area and move towards
Kuskokwim Bay by Saturday. Along the Chukchi Sea and Arctic
coast...a 1007 mb low 110 nm northwest of Point Lay will move
north of Barrow as a 1010 mb by Wednesday morning and move to 74n
150w by Wednesday afternoon. High pressure will build in behind
the exiting low with a 1022 mb high forecasted to be located over
wrangle island by Wednesday afternoon. This high pressure will
weaken as it moves eastward and forecasted to be 1013 mb at 74n
and 150w. Over the central and eastern interior.

North Slope...snow showers continue across chukchi coastline from
Cape Lisburne toward Wainwright with visibilities of 1 to 2 miles.
This will slowly improve across the Chukchi Sea coast as the low
moves north towards Barrow tonight with snow increasing over
Barrow overnight. However...most of the snow showers will move
north of the area with mainly flurries for areas from Barrow west.

West Coast and western interior...recently ended the dense fog
across Nome area and St Lawrence Island middle afternoon as
visibilities improved. However...conditions near Savoonga have
deteriorated once again down to a quarter mile visibility at 230
PM akdt. Along the Chukchi Sea coast expect areas of fog and
flurries to continue through the evening. High pressure will build
over the Chukchi Sea and impact much of western coast. Latest infrared
satellite imagery shows that the disturbance impacting the eastern
interior will push across portions of the western interior
overnight into Wednesday extending from Kaltag through
Hughes. This will bring snow and rain showers to the western and
central interior. There is a slight chance of freezing rain in the
morning for areas from Galena south but the transition from
overnight snow to rain in the afternoon.

Central and eastern this disturbance embedded in
the ridge moved up from the Alaska Range today much of the showery
precipitation was contained in the higher elevations as seen from
Isabel web cameras and quickly cleared out from Tok to Mentasta
Pass and southward. It appeared that models over exaggerated
expected precipitation with the middle level cloud cover. As it moves
across the greater Fairbanks this evening we tapered back on the
initial scattered to slight chance of precipitation...expecting
mainly sprinkle or flurries. Latest radar reflectivity at 300 PM
akdt shows a sharper band developing to the northeast over the
White Mountains. Better chances of evening rain showers
transitioning into snow showers as it moves to the northeast of
Fairbanks. Again expect this band of initially rain showers
transitioning to snow showers to develop and push towards the line
as mentioned towards Galena to Hughes overnight.


Fire weather...
above normal temperatures will continue in the southern interior
areas. Highs are expected to be in the middle 40s to low 50s. Min relative humidity
values in the afternoon will be in the 30 to 40 percent range.
Areas of light precipitation have developed mainly over the higher
terrain and will continue through Friday. No significant gap winds
are expected in the Alaska Range passes through Friday as a weak
surface pressure pattern persists. However...there will be weak
southerly flow on Friday and Saturday through the Alaska Range


Afg watches/warnings/advisories...
brisk Wind Advisory for pkz210-pkz220-pkz225.


Mak Apr 14