Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 201800

Area Forecast Discussion
National Weather Service Bismarck ND
100 PM CDT Tue Jun 20 2017

Issued at 100 PM CDT Tue Jun 20 2017

This update focused on expanding the slight chance of showers from
western into south central ND in both space and time in respect to
recent radar and ASOS/AWOS observations. That did include adding a
small chance of a light shower as far east as Bismarck/Mandan. We
did lower forecast highs in parts of western ND as well where the
cloud cover - while thinning from the west - has resulted in less
diabatic heating and thus a slower temperature rise than earlier

UPDATE Issued at 1005 AM CDT Tue Jun 20 2017

We increased cloud cover percentage across western ND today based
on satellite imagery through mid-morning, which shows a relatively
thick area of mid- and high-level clouds spreading southeastward
across the area in response to warm air advection aloft. We also
chose to retain a slight chance of showers in west central and
southwest ND through early afternoon in respect to upstream radar
trends, though as mentioned previously, the dry lower atmosphere
shown on the 12 UTC Bismarck and Glasgow RAOBs likely means that
few of the radar-observed echoes are actually reaching the ground.

UPDATE Issued at 629 AM CDT Tue Jun 20 2017

Given dry low level air, expect very little, if any showers
across northeast Montana this morning to yield precipitation
reaching the surface as they propagate into southwest North
Dakota. Given the recent bias to be a bit too cool for highs, did
increase forecast temperatures towards the warmer edge of
guidance available as of 10 UTC for today and Wednesday. Thus, a
few 90s are forecast now south central on Wednesday in the warm
sector of the low that will propagate across southern Canada.


.SHORT TERM...(Today and tonight)
Issued at 349 AM CDT Tue Jun 20 2017

Overall today should be a nice quiet day.
Southerly surface flow will kick in warm air advection.
Temperatures today should be in some cases about 10 degrees warmer
than yesterday.

There`s a slight chance of some light showers southwest as a weak
850 wave moves through this morning, but otherwise we should
remain dry through most of the day. An upper level wave will enter
the west tonight and bring with it a cold front. Showers and
thunderstorms could develop late tonight across western North

.LONG TERM...(Wednesday through Monday)
Issued at 349 AM CDT Tue Jun 20 2017

Very cool, below-normal temperatures from late this week through
the weekend highlight the long term forecast period.

A midweek ridge breaks down by Friday and several waves move
through bringing chances for mainly showers and a few isolated
thunderstorms. In addition to rain chances the troughing across
the Great Lakes will bring much cooler air into the region with
highs in the 60s and lows in the 40s by Saturday.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 100 PM CDT Tue Jun 20 2017

VFR conditions will generally prevail throughout the 18 UTC TAF
cycle. However, local sub-VFR weather is possible in isolated to
scattered thunderstorms that may move across western and central
ND tonight and early Wednesday morning in association with a warm
front. Confidence in the impacts at any given location is modest,
albeit highest at KJMS from 10 to 15 UTC where a VCTS was included
in the 18 UTC TAF. Otherwise, isolated and light showers in the
west at midday will move east and weaken this afternoon.




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