Area Forecast Discussion
Issued by NWS Glasgow, MT

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143
FXUS65 KGGW 260237
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
837 PM MDT WED MAY 25 2016

.SHORT TERM...for northeast Montana...tonight through Fri...

Radar showing instability continues south of Glasgow where radar
echoes are showing dBzs spiking to near 50 moving east, so
increased pops for the se zones. trimmed back on evening pops for
the ne zones as it seems that rainshowers probably won`t really
get in there till the overnight. rest of forecast seemed to be in
good shape. TFJ

previous discussion...
A closed upper low continues to be centered over southwest
Saskatchewan. Instability associated with this low is currently
driving scattered showers with embedded thunderstorms across much
of northeast Montana. The midlevel circulation that brought
widespread rainfall to areas near the North Dakota border has
pushed far enough east that its influence is not really being felt
anymore.

Tonight the closed low to the north will slowly make its way
into the Treasure State...where it will continue to drive
scattered showers, and maybe a clap of thunder or two.

Thursday the low will continue overhead, and will pick up a good
moisture fetch from the circulation over North Dakota. This will
increase chances for precipitation to likely during the afternoon.

Thursday evening shower activity will taper off with the setting
of the sun, and Thursday night will be mainly dry as weak ridging
builds in behind the now exiting upper low. The exception to this
will be far northeast Montana where cyclonic flow will keep
isolated showers possible overnight.

Friday will see a digging upper trough starting to approach the
area from the west...transitioning northeast Montana to a
southwest flow aloft. Afternoon heating will cause scattered
shower development during the afternoon, but the Little Rockies
and the furthest west areas of Petroleum and Phillips counties
could see more numerous showers and thunderstorms entering the
area thanks to the digging trough. Gilchrist


.LONG TERM...Fri night through Wed...
As the inherited long term forecast remains in decent shape, little
in the way of change was necessary with this package issuance.
Temperatures were trended downward a degree or two in spots given
overall trends in the 12z consensus model blends. Otherwise,
trough pattern will continue to produce isolated to scattered
showers at times with lows overall in the 40s and 50s and highs in
the 60s and low 70s pretty much each day. Maliawco

Previous Long Term Discussion...

Most of the long-term forecast period will be dominated by an
unsettled, trough pattern - and consequently, the forecast calls
for a prolonged wet period of weather.

At the beginning of the forecast period, the recent meandering low
center will have finally moved eastward and dissipated, leaving a
brief period of very short-wave ridging between disturbances
Friday night through Saturday morning, especially for our eastern
zones.

Saturday morning through Sunday morning, a strong Canadian Rockies
trough will sweep southward and push an average amount of rain
showers and a few thunderstorms through our CWA.

Sunday through early Monday, the flow aloft becomes nearly zonal
for another brief period of quiet weather for the central portion
of our CWA.

Monday morning through Wednesday morning, the most active period
of the forecast shows a more pronounced trough digging through the
northern Rockies and the northern high plains. Some strong showers
and thunderstorms will be possible.

In all cases, tried to blend the PoPs and Wx grids toward the
latest model consensus data.       BMickelson


&&

.AVIATION...

Isolated to widely scattered showers and thunderstorms will
continue tonight before becoming more numerous on Thursday. VFR
conditions will reduce to IFR to MVFR with some of the steadier
shower activity as they pass directly over the TAF sites.

Winds will range from the north and northwest through the TAF
period between 5 and 10 kts. Maliawco/Mickelson


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

weather.gov/glasgow



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