AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1200 PM MDT Fri May 24 2013
.UPDATE...
A few showers left on radar over the northeast zones. The airmass
becomes slightly unstable this afternoon and isolated thunderstorms
are possible. Updated to freshen POPs and WX. Zelzer
&&
.AVIATION...
UPDATED 1800Z
VFR conditions will generally prevail for the next 24 hours.
Westerly surface winds will remain gusty through about 02z. Showers
and isolated thunderstorms may develop along the Continental Divide
later this afternoon moving south to north. Expect terrain
obscuration in the vicinity of showers. Skies clear out after 06z
and should remain VFR.
&&
.HYDROLOGY...Precipitation has ended across the region although local
streams and rivers could see delayed rises through the upcoming
weekend. Persons should be alert for rising river levels and
increased stream flows. A chance of showers and thunderstorms will
develop Saturday and Sunday afternoons but precipitation amounts
will remain low.
&&
.PREV DISCUSSION...
/ISSUED 550 AM MDT Fri May 24 2013/
Friday through Sunday...Friday afternoon and Saturday continue to
show a decrease in widespread precipitation as the upper level trough
retrogrades back towards the Canadian Coast. More shortwave troughs
will move across the area...however they appear relatively
weak...and more likely to cause scattered showers than widespread
precipitation. Have increased the chance for showers and
thunderstorms Sunday morning and afternoon as models show another
decent shortwave trough moving through the area. Exact placement of
the disturbance is not in great agreement so have trended pops still
in the chance and slight chances across much of the area with the
highest percentages along the Rocky Mountain Front and other higher
terrain where the topographical enhancement could be enough to help
initiate convection. Temperatures remain near seasonal averages as
the drying trend helps temperatures rebound for the first half of
the weekend. Suk
Sunday night through Friday...The period begins with a persistent
upper trof over the Pacific Northwest. Short wave energy rotating
out from the base of the trof will continue to ride the southwest
flow aloft into the state. Scattered showers and thunderstorms will
continue to develop through Monday. By Tuesday, the models bring
another upper trof across the Rockies. Lift and diffluent flow aloft
will be strongest over southwest Montana Tuesday afternoon resulting
in another round of showers and thunderstorms. Isolated convective
activity will be possible across central and northern portions of
the county warning area. The remainder of the period, Wednesday
through Friday, will be characterized by continued unsettled
conditions as the area remains under the influence of a broad upper
trof. Temperatures will remain generally above seasonal averages to
start the period with readings dropping below seasonal averages by
the end of the week.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 65 38 69 42 / 20 10 10 20
CTB 61 37 66 39 / 10 10 10 20
HLN 64 40 70 45 / 20 10 20 20
BZN 66 36 72 41 / 10 10 20 10
WEY 59 33 67 38 / 10 0 10 10
DLN 62 37 70 42 / 10 10 30 20
HVR 69 41 74 44 / 20 10 10 40
LWT 64 40 69 45 / 10 10 20 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
