Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 162139
Area Forecast Discussion
National Weather Service GLASGOW MT
239 PM MST Mon Jan 16 2017
.SHORT TERM...for northeast Montana...tonight through Wed...
An upper level ridge brought in the sunshine today with light
winds. The result was a day that was generally warmer than
normal, except for the river valleys where there was no wind to
scour out the lower layers under the snowpack caused inversion.
Models show all 850mb temperatures above 0C.
Tonight a weak disturbance moving into BC from the Gulf of alaska
will begin to knock down the ridge, resulting in a Chinook and
increasing temperatures. Thickness heights continue to rise. A
southwest surface breeze develops, along with zonal flow aloft.
Expect a significant increase in temperatures for Tuesday,
possibly around 15F above normal, plus or minus. The resulting
snow melt will lead to increasing boundary layer moisture for
Tuesday night. Fog may develop overnight, depending on winds.
Temperatures are expected to continue warming, but could be
influenced by any fog that may develop. So there is some
uncertainty with temperatures, as has been during the last several
days with the slow, but splotchy warm-up.
.LONG TERM...Wed night through Mon...
Mild weather expected through the period. Precipitations chances
will be low as the storm tracks will be through the Great Basin
and into the southern or central Plains. A more northward tracking
wave could produce some mixed precipitation over the northern
Plains by the weekend. Only minor changes made to the current
Previous long term discussion...Upper ridge moves to the east on
Thursday with mild and dry weather continuing. Flow aloft turns
southwest to southerly Thursday Night and Friday as a broad upper
trough moves into the Western US with an upper low off the BC
coast. A weak cold front Thursday Night could bring a slight
chance of rain and snow showers to the southern part of the
Temperatures will be some what cooler on Friday but still above
normal. Shortwaves within the broad upper trough will move north
across the Plain States between Friday Night and Sunday bringing
chances for light snow showers into the area. At the same time,
the main trough splits and the southern branch moves to the east
while the northern branch lifts north into the Canadian Prairies
by next Monday and an upper ridge builds into Montana with dry
VFR. A warm, Pacific airmass will be in control much of this
week. High pressure tonight will bring mostly clear skies to the
area. Strong winds off the front range Tuesday morning could
produce some LLWS with a shallow inversion still in place over the