Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Glasgow Montana
243 PM MDT Friday Mar 27 2015
Short term...for northeast Montana...tonight through Sunday...
upper ridge over the area today providing beautiful conditions with
temperatures about 20 above normal. However a shortwave off the
Pacific northwest coast is cruising east and will cross Montana Saturday.
NAM and GFS similar on what will play out with sensible
weather...European model (ecmwf) a bit wetter for the southern zones Saturday.
Warm front over the Dakotas will be overtaken by a cold front
associated with the said shortwave. A prefrontal trough looks to
move though middle-day introducing the winds. European model (ecmwf) highlights this
better with quantitative precipitation forecast. Steep middle-levels should be good enough for isolated
thundertorms. Wrap-around feature then drops southeast across the
County Warning Area bringing a better chance of rainshowers for the evening then
clearing with slightly cooler and drier airmass moving in.
On Sunday...upper ridge over the Pacific northwest builds in with a surface
low over Alberta to help warm things up. Temperatures should top out in
the lower to middle 60s with lighter winds than Saturday. Tfj
Long term...Sunday night through Friday...
tweaked current forecast to 12z forecast models. Main change seen
was lower winds for Tuesday evening. Quantitative precipitation forecast/S look to be better
concentrated Tuesday night. Later shifts will have to watch closed
low dropping south into the vicinity for snow chances. Tfj
upper ridge rebounds following weekend cold front for warm and
dry conditions returning for early next week. Next shortwave
pushes through the ridge into the northern rockies by Tuesday with
a strong Lee cyclone developing over Alberta. Cold front
associated with the system forecast by medium range models to push
through eastern Montana Tuesday afternoon. Moisture holds back
until the low begins to move across the Canadian prairies wrapping
into northern Montana with the cold air advection behind the
system. Winds also expected to increase with the tight
gradient...cold air advection and cyclonic jet Tuesday night into
Upper flow remains zonal to slightly cyclonic into the end of the
week with another shortwave dropping into the Great Basin on
Thursday. This will maintain cooler and more unsettled weather
into Friday. Ebert
flight conditions: VFR.
Synopsis: conditions will remain quiet until a cold front arrives
Saturday. This will increase winds from the west with gusts to 45
kts in some places. Rainshowers and possibly a thunderstorm will
threaten the area Saturday afternoon and evening.
Equipment: kgdv ceilometer is out. Until it returns...
amend limited to visible and wind. Gah/tfj
will keep Fire Weather Watch going as conditions continue to look
marginal at best. Drier conditions Saturday will occur to the south.
Shower possibilities will keep minimum humidities in the upper 20s
or higher across the current watch area. Models did back off on
winds slightly. Current thinking was to drop watch but will let
night shift get another look at things. Tfj
a cold front moving through the region on Saturday afternoon and
evening will generate strong to very strong winds of 25 to 35 miles per hour
with gusts of 45 to 55 miles per hour. However rain showers are also
expected. Models are still evolving on the amounts and location of
the rain. So far the chance for wetting rains are best north of
the Missouri River and east of Fort Peck Lake.
There seems less uncertainty concerning winds and relative humidity values. The
red flag decision chart places fire weather zones 135...136 and 137 at
possible for a fire weather headline with relative humidity values in the upper 20s
and lower 30s. So will go ahead with a Fire Weather Watch for those
areas from noon to 9pm Saturday.
Fire Weather Watch from Saturday afternoon through Saturday
evening for mtz135>137.
High wind watch from Saturday afternoon through Saturday evening
for southwest Phillips.