Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
1253 PM akdt Monday Jun 29 2015
current model runs exhibit similar solutions out through
Thursday...begin to diverge slightly Friday and become
increasingly divergent thereafter. Ensemble means are preferred in
the longer term
Weak upper level ridging with axis Dall Point-Galena-100 miles
north of Fairbanks and eastward into the Yukon territory. The weak
upper level ridging will persist through Thursday...by Thursday
the ridge axis will extend from Cook Inlet to near Fairbanks and
northeastward into the Yukon territory.
A short wave trough aloft will swing northwestward across the
central and eastern interior Tuesday night through Thursday
night...bringing in more moisture combined with synoptic scale
lift. This will result in widespread significant rainfall amounts
over the southeast interior.
The current GFS/NAM runs are in agreement in progging significant
rainfall over the northwest two thirds of zone 224...the eastern
half of zone 223...and the western two thirds of zone 226...48
hour rainfall amounts ranging from 1 to locally 3+ inches. Nam12
indicates significant rainfall over much of zone 226... with GFS
noticeably smaller amounts. European model (ecmwf) model appears to put the main
rainfall maximum too far to the west. GFS/NAM blend is
preferred...maybe weighting the GFS a bit more.
Weakly unstable air will persist over the most of the southern
and eastern interior through tonight the air mass is expected to
become more unstable over most of the northern and eastern
interior and in southern parts of the western interior Tuesday as
the short wave trough and southeast flow bring in more moisture.
By Thursday...the instability will be pushed into the northeastern
In the extended period...the ensemble means are in agreement
building a very strong upper level ridge over northern Alaska
by Sunday...after a period of somewhat cooler weather as a short
wave trough sweeps across northern Alaska. Current GFS/European model (ecmwf)
solutions are widely divergent...operational GFS appears to be
overbuilding the upper level ridge with 850 mb temperatures which
would break all time records.
extensive wetting rains are expected over much of the southeast
interior from Tuesday through Thursday. Hot and dry conditions
are expected to redevelop over the weekend with the rebuilding of
a strong upper level ridge.
there is potential for significant rainfall in the southeast
interior. It is probably too early for the issuance of any
watches...but may put headlines for heavy rainfall in
the affected zones.
dense smoke advisory for akz216-akz219-akz221.
Small Craft Advisory for pkz210.
Rf Jun 15