Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 122336

Area Forecast Discussion
National Weather Service Bismarck ND
636 PM CDT Mon Mar 12 2018

Issued at 623 PM CDT Mon Mar 12 2018

Quiet weather continues over the area. Forecast models still hint
and fog developing tonight, but have trouble pinpointing where it
will develop. Therefore, will continue to carry patchy fog
throughout the area.


.SHORT TERM...(This evening through Tuesday)
Issued at 206 PM CDT Mon Mar 12 2018

Fog potential overnight is the main highlight of the forecast

A 1036 mb surface high under northwest flow aloft was centered
over the southern Canadian prairies into central North Dakota. A
strong ridge was shifting into the northern Rockies to our west
with broad low pressure over the eastern CONUS, providing our
persistent northwest flow pattern. A shortwave embedded in the
northwest flow was moving through eastern Wyoming, providing the
high clouds over our southwest. Otherwise the seasonably cool high
pressure pattern contributed to mostly clear skies and light
winds across the area.

Patchy fog is possible tonight central and northwest centered with
the surface high and strong subsidence aloft. Less confidence in
fog for the southwest with southerly flow on the west side of the
high pressure axis.

Mild and mostly clear skies again on Tuesday with the surface high
shifting into eastern South Dakota. Westerly warm air advection
through the day will lead to highs in the 40s across areas of the
west, especially in the southwest where there`s less snowpack.

.LONG TERM...(Tuesday night through Monday)
Issued at 206 PM CDT Mon Mar 12 2018

Warm air advection continues Tuesday night into Wednesday as the
upper level ridge moves east into the Plains. Broad low pressure
develops over the western CONUS, with an associated lee side
trough over eastern Montana developing relatively warm southerly
flow in the mid-levels. Wednesday remains the warmest day in the
forecast period with highs in the mid and upper 30s northwest and
central to mid 40s in the southwest.

Early Thursday southwest flow develops over the Northern Plains
as a deep western trough sets up. 12Z global models are in decent
agreement with an embedded wave bringing a rain/snow mix to
western North Dakota on Thursday. A possibility of freezing rain
will depend on the depth of the warm layer ahead of the wave.
Otherwise we kept a rain/snow mix in the forecast until more
details come to light.

For the latter portion of the period global models diverge on the
progression of the upper level western low. However with the
persistence of the low pressure to our west and an active
pattern, chances for rain and snow are in the forecast Friday
through the end of the forecast period. CIPS Analog guidance
suggests an active precipitation pattern through Monday, even with
high uncertainty on timing and strength of any system arriving
during that period.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 623 PM CDT Mon Mar 12 2018

Patchy fog is expected to develop over central and western North
Dakota late this evening and remain through mid-morning Monday.
With that said, there is still a lot of question on exactly where
the fog will develop and how poor visibility can become.
Therefore, will mention VCFG for all TAF sites until we have
higher confidence on the fog development.




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