Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Glasgow Montana
341 am MDT sun Mar 29 2015
Short term...for northeast Montana...today through Tuesday...
cold front pushing through the Dakotas with high pressure building
into the northern rockies. Showers have cleared out of the region
along with most of the clouds...and winds continue to weaken.
Wind speeds have dropped below lake wind criteria so have
cancelled the advisory for Fort Peck Lake.
Upper ridge expected to build east over the next few days
resulting in dry weather and slowly warming temperatures. Another
strong upper trough pushes into the Pacific northwest on Tuesday...
sending a cold front across The Divide in the afternoon. Strong
compressional heating expected ahead of the front potentially
sending temperatures into 70s or even low 80s Tuesday afternoon.
Cold front currently not expected to move out of central Montana
until late afternoon. Ebert
Long term...Tuesday night through Sunday...
the latest 12z model guidance continues with a cold front Tuesday
night reaching northeast Montana. A surface low and closed upper
low will track north of the region across southern Saskatchewan.
This will act to greatly enhance the surface pressure gradient
across the County Warning Area. Thus...while shower and possibly thunderstorm activity
can be expected Tuesday night and Wednesday...the larger concern
looks to surround gusty westerly wind potential.
Decent cold air advection behind the cold front along with this tight pressure
gradient will likely mean business. Latest guidance is pointing to
sustained wind speeds in the 20-30 miles per hour with gusts in the 40-50 miles per hour
range. In time this could easily become a strongly worded lake
Wind Advisory situation...and will have to watch the usual windy
locations for high wind. This is several days out from now and
with several factors involved confidence is not yet there on
that...but if nothing else expect very gusty conditions Tuesday
night and Wednesday across northeast Montana. As this event enters
the day 3 period...would like to inspect more closely lapse
rates...among other parameters...available in the NAM BUFKIT
forecast soundings across the region to ascertain more detail.
After a couple of days...some mesoscale guidance will be able to
also offer some input as to what to expect.
Northwest flow aloft in advance of a Pacific shortwave ridge will
become established across the northern High Plains in the wake of
the Tuesday night/Wednesday system. Embedded in this flow will be
shortwaves...somewhat difficult to time given increasing spread in
the 500mb height ensembles this far out in the extended period.
Nevertheless this pattern supports near climatology probability of precipitation with a daytime
slight chance of rain showers and nocturnal rain/snow mix with
cooler thermal profiles at night.
While precise timing is difficult to pin down...12z European model (ecmwf)/GFS have
broad consensus on having a Pacific Ridge translate east across
Montana which would lead to drier conditions and moderating
temperatures. Given this information...will have a dry forecast to
finish out the long range period...for now. Maliawco
prevailing VFR ceilings and visibilities are expected today across the
terminals. Light west winds early this morning will increase to
10-15 kts by this afternoon. Maliawco