Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 290537

Area Forecast Discussion
National Weather Service Bismarck ND
1237 AM CDT Wed Mar 29 2017

Issued at 1224 AM CDT Wed Mar 29 2017

Only minor tweaks made to fog and precip forecast for tonight. Fog
is expected to develop west and north. Light rain will continue
across north central North Dakota.

UPDATE Issued at 931 PM CDT Tue Mar 28 2017

Main change for late evening update was to increase precipitation
chances quite a bit over many western locations as showers have
been reluctant to dissipate. Radar reflectivity was looking rather
high over the Powers Lake area but with the beam near freezing
over that area figured some bright banding was occurring. With
that said, we still called some spotters just to be sure and they
said precipitation was on the lighter side. Earlier this evening
we did have a few lighting strikes over southwest North Dakota,
but guidance continues to suggest that the instability will
continue to weaken, so will keep thunderstorm chances in for maybe
another hour. Area of precipitation should continue to weaken
through the evening into the overnight, with only a few lingering
showers. Will continue to carry fog overnight with the moist lower

UPDATE Issued at 631 PM CDT Tue Mar 28 2017

Rain has become more widespread over portions of northwest North
Dakota, so have increased precipitation chances to account for
this. Otherwise, previous forecast remains on track.


.SHORT TERM...(This evening through Wednesday)
Issued at 308 PM CDT Tue Mar 28 2017

...A slow moving frontal boundary will provide a chance of
showers tonight and Wednesday...

Currently, surface high pressure over Canada and low pressure over
the central high plains is producing a southeast surface flow over
western and central ND. An upper level impulse and daytime diurnal
heating is producing an area of showers over north central and
western ND this afternoon. In addition, our convergent low level
flow is still producing some fog over the north central.

Tonight and Wednesday...Due to a digging trough over the southern
plains and another digging trough off the west coast, our impulse
tracks very slowly to the east. Shower chances in the west and
north central tonight will shift east into central ND on
Wednesday. With surface temperatures mostly above freezing, do not
anticipate any significant freezing precipitation issues.

Also, the fog across the north central may once again expand in
areal coverage again tonight, as indicated by latest HRRR/RAP
mesoscale models. Bufkit soundings do not indicate as deep a layer
of moisture at the surface as was available last night. So will
keep a mention of fog in the forecast, but will once again let the
evening shift monitor things as confidence is too low for issuing
a dense fog hazard at this time.

If we do see more widespread fog again tonight, this may hold down
our temperatures on Wednesday. Otherwise, we are expecting highs
back up into the lower 50s north central, and the lower 60s over
the west central into far southwest ND.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 308 PM CDT Tue Mar 28 2017

An active pattern continues into the long term part of the
forecast. However, with a split flow pattern the majority of the
energy either moves north of the forecast area or well to our
south. We are expecting an upper level trough to traverse the area
late Thursday into early Saturday. This is expected to produce
scattered showers with generally light amounts. Precipitation may
fall as a mix Friday night into Saturday morning across the
northwest and north central. Another system moves into the plains
early to mid week, next week. There is still a lot of model
uncertainty with this system and will it will need to be watched.
But at this time a southern track is favored. The GFS is currently
an outlier of the deterministic models with a colder and wetter
solution for western and central ND. Once this system passes by,
upper level ridging builds over the region with a warm-up towards
the end of next week.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1224 AM CDT Wed Mar 29 2017

At midnight CDT the combination of weak surface wind flow and a
stationary frontal boundary across western North Dakota will favor
areas of fog across northwest North Dakota impacting KISN with VLIFR
through 13z then becoming VFR. MVFR stratus will also move into
KDIK between 12-17Z. Otherwise VFR.




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