Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 010447

Area Forecast Discussion
National Weather Service Bismarck ND
1147 PM CDT Sun Apr 30 2017

Issued at 1147 PM CDT Sun Apr 30 2017

Latest regional radar and surface observations show a narrow line
of rainshowers from near Plentywood south to Glendive, Montana.
This is associated with the leading edge of weak synoptic scale
ascent associated with an advancing cold in eastern Montana and
a shortwave trough in north central Montana. Thus far, rainfall
amounts have been light, with a Trace reported at Wolf Point,
and 0.02 in Miles City. This line will continue to push into
western ND overnight. Pops look good defining this line and no
adjustments needed. Ascent/instability increases Monday leading
to increasing pops with likely rain showers and isolated
thunderstorms west. Forecast remains on track.

UPDATE Issued at 923 PM CDT Sun Apr 30 2017

No major updates needed. Just blended the latest observations
with the going forecast. Echo returns in the northwestern part of
the state are not likely reaching the ground with very high
temperature dewpoint spreads.

UPDATE Issued at 641 PM CDT Sun Apr 30 2017

No major changes were needed with this update. Just tweaked sky
cover to reflect most recent satellite imagery and high resolution
model iterations. Otherwise, just blended the latest observations
with the going forecast.


.SHORT TERM...(This evening through Monday)
Issued at 320 PM CDT Sun Apr 30 2017

A cooler, cloudy and showery day expected on Monday. Gusty northwest
winds can also be expected in the west - especially southwestern ND.

Currently, the western edge of a high pressure ridge axis extended
across southern Ontario, northern Minnesota, and into northeastern
North Dakota. The large deep storm system in the central Plains was
centered over Kansas/Missouri, with the northern extent of a cirrus
cloud shield reaching eastern South Dakota and southern Minnesota
with some extending into southeastern North Dakota. A northeast wind
flow had developed over southeastern ND in response to the central
Plains storm. Meanwhile another low pressure center was over
southern Alberta with a trough extending south across eastern
Montana/Wyoming. Winds over western ND had become southerly today in
response to the western low/trough.

Regarding the central Plains to Great Lakes storm:
Tonight the central Plains low is forecast to lift northeast into
eastern Iowa by daybreak Monday, then continue towards the Great
Lakes by Monday evening. this is a slightly more eastward track than
yesterday`s models indicated. The precipitation shield from this
storm may just miss the Dickey and Lamoure County areas. Have taken
precipitation chances out of this area with this forecast package.

Regarding the western low/trough:
The upper level shortwave associated with this system will move
southeast out of Alberta tonight and approach the northwest corner
of North Dakota, then expand south across the western Dakotas on
Monday. The surface low will also move southeast, reaching
southeastern Saskatchewan by daybreak Monday, sweeping southeast
across North Dakota and arriving in eastern South Dakota by Monday
evening. Scattered showers are expected to develop over far
western North Dakota tonight, then expand and become more numerous
over western and central North Dakota on Monday. There should be
enough instability with this system for some isolated
thunderstorms from late morning through early evening. An upper
level jet streak will accompany this system, mainly across eastern
Montana and into northeastern Wyoming and western South Dakota.
Strong gusty northwest winds will develop behind the low/trough,
but the strongest winds should be west and south of our area.
Still - gusty northwest winds of 20 to 30 mph are expected over
southwestern North Dakota on Monday.

.LONG TERM...(Monday night through Sunday)
Issued at 320 PM CDT Sun Apr 30 2017

Cool with chances of showers early in the week, then dry with a
warming trend.

The eastern low moves northeastward slowly across the Great Lakes
Monday night, and continues lifting northeast towards Hudson Bay
Tuesday. Meanwhile farther west across the Northern Plains, a
northwest flow aloft remains in place. A few shortwaves in the
northwest flow aloft will keep conditions a bit cooler with chances
of showers in our area through Wednesday.

A building western ridge begins expanding into the Northern Plains
beginning Thursday, bringing a warming trend with dry weather
Thursday into next weekend. The western ridge elongates and builds
well north into north central Canada by Saturday/Sunday. Meanwhile
another west coast trough develops and begins moving east across the
Rockies late in the weekend. We may see a return of showers and
thunderstorms by Sunday/Sunday night.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1147 PM CDT Sun Apr 30 2017

Line of light rainshowers approaching KISN will move through by 08z.
Have utilized a tempo group as dry air initially will need to be
moistened up before said precipitation will reach the ground.
Showers are ahead of a cold front which pushes through the western
terminals 12z-15z Monday. Expect the best chances for rainshowers
and mvfr cigs at KISN/KDIK. Also, isolated thunderstorms are
expected in western ND Monday afternoon, but too remote at this
time for a mention at KISN/KDIK. VFR at remaining terminals with a
vcsh at KMOT/KBIS later Monday afternoon.




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