Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Glasgow Montana
324 am MDT Thursday Aug 28 2014
Short term...for northeast Montana...today through Saturday...
Water vapor imagery and 500 mb height field shows a very zonal
flow across the northern tier states including Montana with just a
bit of the Central High plains storm system reaching its cloud
shield over southeast County Warning Area.
Today...just enough influence from a ridge of high pressure from
the south...in the wake of the central states trough...will allow
temperatures to climb once again well into the upper 80s. Some
locations will likely flirt with the 90 degree mark.
Early Friday morning...a very subtle short-wave trough or
disturbance is expected to bring a slight chance for thunderstorms
to the County Warning Area...but by middle-day Friday...that chance will consolidate
and focus over our southeast zones. Enough successive model runs have
concentrated this precipitation of the same area for a number of days
that I felt it was warranted to increase probability of precipitation there to likely.
Might not amount to much...but I do expect some accumulating
precipitation there by middle-day Friday.
For Saturday...a much-larger and more-pronounced low pressure
trough envelopes the northern rockies...directing moisture and
instability into our region. Model break out convective
precipitation for our County Warning Area by Saturday afternoon...but it looks
like the bulk of the thunderstorms will impact our eastern zones Saturday
afternoon and evening...basically along a line from Plentywood to
Long term...Saturday night through Thursday...
Broad trough over the western states this weekend expected to
flatten as it lifts toward eastern Canada next week and another
trough digs toward the Pacific northwest. Upper flow over Montana
will thus gradually back from northwest early in the week to
southwest by the end of the forecast period.
Lingering showers or thunderstorms expected at the beginning of
the period as the upper trough moves from the northern rockies into
the plains. Much cooler air under the trough will result in maximum
temperatures of 5 to 15 degrees below normal for Sunday and
Monday. As the upper flow backs temperatures will warm...returning
to near normal values by Wednesday.
VFR. West winds 10 to 15 knots will develop by this afternoon.
A cold front moves into southern Saskatchewan late today with
clouds increasing overnight.
Flood warnings remain in effect for the lower milk river and
Beaver Creek in eastern Phillips and western Valley County. The
Flood Warning for the Musselshell river has been cancelled but Box
Elder and Flatwillow creeks are still running high...so a Flood
Advisory remains in effect for portions of Petroleum County.
For more details... please refer to the individual Flood Warning