Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 241346

Area Forecast Discussion
National Weather Service Bismarck ND
846 AM CDT Sun Sep 24 2017

Issued at 846 AM CDT Sun Sep 24 2017

Changes with this update centered on adjustments to the hourly
precipitation chances through midday, namely to increase them to
around 100 percent in south central ND and the James River valley
and to decrease them further in southwest ND through mid morning.
Both adjustments were based on observational trends and recent
rapid-refresh, high-resolution model guidance, both of which show
the primary rain moving through south central ND as of 1345 UTC in
association with a band of modest mid-level frontogenesis based in
the 850 to 700 mb layer. Guidance including RAP iterations through
its 12 UTC cycle suggests that frontogenesis will wane through 18
UTC, and precipitation will concurrently diminish this afternoon.

UPDATE Issued at 620 AM CDT Sun Sep 24 2017

Main changes to the forecast will be the short term POPs which
have been diminishing across the southwest. Mid level water vapor
loops show a river of moist flow from Nebraska north into central
and eastern North Dakota which will feed the showers today. There
is some dry air at low levels filtering into the southwest though.
Cloudy and cool with showers central and east with widely
scattered showers west.


.SHORT TERM...(Today and tonight)
Issued at 316 AM CDT Sun Sep 24 2017

Widespread showers will continue across the region for the
remainder of this morning then begin to diminish rapidly from
west to east during the daytime hours. The highest rain amounts
Will be in the southern James River valley with nearly two inches
expected with generally around a half inch central to lesser
amounts west. Highs today will be in the upper 40s to mid 50s.

After the showers trail off tonight clouds will remain in place
most areas so expect minimum temperatures Monday morning to
remain above the frost thresholds for the most part. lows tonight
will be in the upper 30s west to mid 40s east.

.LONG TERM...(Monday through Saturday)
Issued at 316 AM CDT Sun Sep 24 2017

The long term will see the h500 trough slowly move east and fill
keeping cyclonic flow aloft and at least scattered showers across
the northern plains Monday into Tuesday. Following Tuesday
rising h500 heights can be expected across the northwest US.
Although weakly cyclonic flow remains over North Dakota in a
generally northwest flow regime through Thursday, there should be
only minimal chances for rain. High temperatures will rebound
into the 60s. Low temperatures will be in the mid 30s to lower 40s
so patchy frost will be possible next week but a widespread
freeze is still not expected through at least Saturday.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 846 AM CDT Sun Sep 24 2017

Persistent trough of low pressure will bring showers to west and
central North dakota through today. Widespread IFR conditions
expected to persist KDIK-KBIS-KJMS today and tonight. MVFR/IFR
conditions at KMOT will become MVFR by late morning, then VFR
by evening. MVFR to VFR conditions at KISN will become prevailing
VFR ceilings by afternoon.




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