Area forecast discussion
National Weather Service Glasgow Montana
328 am MDT Sat may 25 2013
Short term...for northeast Montana...today through Monday...
shortwaves on southwest flow aloft will interact with quasi-
stationary front over eastern Montana the next 3 days to bring
several chances for showers and thunderstorms. The southwest flow
aloft will be between an upper trough/low over the Pacific
northwest and an upper ridge over Minnesota. The southeast winds
on the east side of the front today will bring increasingly moist
air into eastern Montana which will combine with daytime heating
to make the atmosphere more unstable as the day wears on. With the
frontal boundary expected to be in Phillips and Petroleum counties
this afternoon...the best instability will be to the east. With
lifted indicies falling to near -4 this afternoon and cape
increasing to 1000-1500 j/kg...conditions look favorable for the
development of severe thunderstorms that will linger into evening.
The likelihood of severe weather will diminish with the loss of
daytime heating tonight but showers and thunderstorms will remain
likely with the front remaining in the area.
The possibility of severe weather will repeat itself on Sunday
with little change in the pattern and possibly even Monday as the
frontal boundary remains in the area with southwest flow aloft.
Will maintain a good chance of showers and thunderstorms through
the short term along with a mention of severe weather on Sunday.
Forrester
Long term...Monday night through Saturday...
the upper trough that will begin to affect the region this weekend
will continue to have an influence through next week. The upper
closed low will slowly churn shortwave energy out through the
weekend before an upper jet maximum off the Pacific begins to dig the
upper trough further south and east into the Desert Southwest on
Tuesday. When this happens...a shortwave trough will split off the
main flow into Canada...and leave the region over brief short
ridging late Tuesday into Wednesday. The brief ridging period
will be just about the only break from continued chances for
precipitation for the remainder of the long term.
The upper jet maximum will continue to push the trough to have a more
negative tilt with each day...before the jet maximum finally
progresses through the base of the trough by Friday and begins
moving further eastward. This will continue to place the region
over favorable precipitation chances for just about all of next week. By
next weekend...the GFS and European model (ecmwf) disagree slightly as the GFS
wants to quickly erode brief ridging and allow another Pacific
northwest low to bring more precipitation. The European model (ecmwf) wants to keep
ridging around a bit longer...and have a closed low possibly ride
down the Pacific coast. Either way...before that occurs...it
appears a wet and unsettled pattern is in store for the long term.
Barnwell
&&
Aviation...
VFR conditions are expected for most of the taf cycle...before
convective activity begins this afternoon. Initially...IFR conditions
or worse will be likely for kgdv and ksdy during the afternoon
hours amid strong to severe thunderstorms...which will spread to all
remaining taf sites through tonight and possibly into the early
morning hours on Sunday. Bmickelson/Barnwell
&&
Glasgow watches/warnings/advisories...none.
&&
$$
Weather.Gov/Glasgow
