Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Great Falls Montana
1025 PM MDT sun Mar 29 2015

Updated aviation discussion

not much need for an update this evening. The winds are the
biggest problem, but they are slowly trending downward. Db


updated 0425z.
VFR conditions will occur. Ceilings at or above 15000 ft will
become clear skies from the west after midnight. Monday afternoon
skies will range from clear to scattered clouds between 12000 and
14000 ft. Gusty westerly winds will redevelop Monday afternoon with
speeds of 15 to 25 kts. However over the Rocky Mountain front Monday
afternoon speeds will be in the range of 25 to 35 kts with gusts to
45 kts. Winds will subside Monday evening. Blank


Previous discussion...
/issued 535 PM MDT sun Mar 29 2015/

Tonight through upper level high pressure ridge is over
the West Coast. High level moisture associated with a shortwave
moving over the top of the ridge has been moving across The Rockies
but lower levels will remain dry. However, this shortwave will keep
a surface pressure trof in place over Alberta and keep breezy
conditions across the slopes of The Rockies through the night. The
ridge will be over The Rockies Monday and a low pressure trof will
approach the West Coast Monday night and move on shore Tuesday.
Winds aloft will strengthen as the shortwave approaches but not much
support for damaging winds except over the northern rockies. With
the ridge moving east of the zones Monday night, heights aloft will
be dropping and the air mass will destabilize. The approaching
shortwave has been slowed by the models over the past two days and
this slower movement will allow daytime heating ahead of the front
to further increase instability and a chance of thunderstorms will
develop Tuesday afternoon. Zelzer

Tuesday night through Sunday...similar to yesterday's discussion,
latest forecast model solutions have further slowed the shortwave
trof and its associated cold front and precipitation arriving tues.
Cold frontal passage and much of the valley rain/mtn snow are now
projected to move through our region on tues eve and overnight.
Precip amounts haven't changed much though, with just a few
hundredths to around a tenth of an inch expected. Once that system
departs to the east, we'll see cool, moist northwest flow persist
from Wed eve through Fri morning. Some weak disturbances and
patches of moisture will move through the flow during that time,
generating periods of scattered rain/snow showers across the
region. Again, precip amounts are expected to be minimal, with the
highest values expected to occur over the southwest counties. Models
are now in better agreement that a weak high pressure ridge will
bring more westerly flow aloft and dry conditions from Fri aftn
through Sat eve. By sun, another Pacific weather system arrives with
more scattered showers. High temperatures will be close to seasonal
averages (low to mid 50s) each day for the remainder of this week.


Preliminary point temps/pops...
gtf 41 70 45 69 / 0 0 0 20
ctb 42 66 42 61 / 0 0 0 10
hln 41 70 41 68 / 0 0 0 20
bzn 32 70 36 71 / 0 0 0 30
wey 25 57 29 60 / 0 0 0 20
dln 36 68 39 68 / 0 0 0 20
hvr 36 69 37 72 / 0 0 0 20
lwt 40 68 43 75 / 0 0 0 20


Tfx watches/warnings/advisories...



National Weather Service Glossary of Abbreviations