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Area forecast discussion 
National Weather Service Great Falls Montana
1045 am MST sun Nov 29 2015


Most of today's forecast remains valid. Just adjusted high
temperatures downward by a couple degrees for the Great Falls to
Havre corridor and upward by several degrees for the Lewistown area
based on a persistence forecast and per latest observed temperature
trends. Expect lingering areas of freezing fog in
valleys...including the Helena dissipate during the 11
am to 1 PM timeframe. Otherwise fair weather will dominate once
again today as high pressure remains in control. Jaszka


Previous discussion...
/issued 438 am MST sun Nov 29 2015/

Today through Tuesday...forecast area will continue to be influenced
by an upper ridge over southwest Canada and a closed low currently
over Utah/co/WY border region. Over time, the upper low will move
eastward across Wyoming and into the northern plains. For today
through Monday this will keep Montana beneath a dry northeast flow
aloft. Far southwest Montana will see some increase in cloud cover
and a slight chance of showers near Yellowstone Park due to the
upper low but the remainder of the forecast area will remain dry and
quiet. Temperatures will remain below seasonal averages and surface
winds are expected to be light. By Tuesday the low will have moved
far enough east that the Canadian ridge will begin to edge eastward
across Montana. The return of westerly flow aloft and falling
pressure in Alberta is also expected to bring breezy conditions to
the east slopes of The Rockies. Mpj

Tuesday night through Sunday...extended models remain in good
agreement... so little change from previous forecast. Upper level
closed low pressure system expected to be approaching Great Lakes
regions at start of period with another large low pressure trough
moving into the eastern Pacific. Montana left under the high
pressure ridge between these systems through Thursday. Effect should
be mostly sunny skies and seasonably mild temperatures. By
Friday...the low pressure trough approaching from the west will
begin pushing inland. As the leading edge approaches
Montana...expect winds to increase...especially along the Rocky
Mountain front. At this time chances for precipitation are low and
limited to the west and Southwest Mountains. Trough expected to move
through the region on Friday and off to the east Saturday. This
allows the high pressure ridge to again rebuild over Montana in
advance of another trough dropping out of the Gulf of Alaska
approaching the Pacific northwest.

Temperatures are a complicating factor to the forecast. The cold air
currently settled into the valleys of southwest Montana could remain
in place through Wednesday or Thursday. Continued trend of
undercutting guidance for forecast temperatures through much of next
week. As winds begin to increase with the approaching low pressure
trough...there should be enough atmospheric mixing to warm things


Aviation...updated 1745z.

Persistent high pressure and dry airmass over aerodromes will result
in scattered high clouds and widespread VFR conditions through
period. Low level moisture will linger in Helena valley with areas
of dense fog and LIFR/vlifr conditions at khln until around 21z.
Britton &&

Preliminary point temps/pops...
gtf 28 12 31 20 / 0 0 0 0
ctb 41 14 41 20 / 0 0 0 0
hln 16 4 23 10 / 0 0 0 0
bzn 19 -2 22 -2 / 0 10 10 0
wey 28 -12 26 1 / 10 20 20 10
dln 16 -1 20 -1 / 0 0 0 0
hvr 25 6 28 13 / 0 0 0 0
lwt 32 13 33 20 / 0 0 0 0


Tfx watches/warnings/advisories...



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