Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 290530

Area Forecast Discussion
National Weather Service Bismarck ND
1230 AM CDT FRI JUL 29 2016

Issued at 1224 AM CDT Fri Jul 29 2016

At midnight CDT surface high pressure extended across the eastern
Dakotas and Minnesota. Wind flow around the high was bringing a
weak easterly upslope flow to southwest North Dakota. There is
some concern for fog formation in this area but past few nights
its been hard to get much fog going. Will wait and watch the
visibilities. Removed some small areas of thunderstorms chances
early this morning south central. Otherwise current forecast looks

UPDATE Issued at 934 PM CDT Thu Jul 28 2016

The forecast continues to remain on track with no changes other
than to blend to observed trends through 02 UTC.

UPDATE Issued at 641 PM CDT Thu Jul 28 2016

Other than to blend to observed trends through 23 UTC, no changes
were required to the forecast through the night with surface high
pressure in place.


.SHORT TERM...(This evening through Friday)
Issued at 350 PM CDT Thu Jul 28 2016

Main forecast problem in the short term period will be minimal
precipitation chances.

Currently, High pressure is situated over northern north dakota
with a weak surface trough in southeast Montana. Skies were mostly
cloudy across southwest and south central ND with partly cloudy
skies under the surface high to the north. A shortwave was
tracking southeast across southeastern MT which was helping to
keep showers over the southwest and far south central.

Late this afternoon and tonight...Cape of around 500-1000j/kg over
the far southwest could support a brief thunderstorm late this
afternoon into early this evening, but with weak lapse rates an
minimal shear, the threat for severe weather is low. Otherwise
expect slowly clearing skies in the northeast portion of the CWA
but as the surface high continues to drift east, low level
convergent flow across the south will likely keep considerable
cloudiness across the southwest and south central through the
night. Will pass on to the evening shift the possibility of fog
but opted to leave it out at this time.

Friday and Saturday wee will see slowly warming temperatures as
the surface high currently over the forecast area slides east and
a southerly return flow sets up. In the mid levels a weak
shortwave trough will move through the area Friday afternoon and
evening. With only slight instability think the risk of
thunderstorms will be low, especially north, but a slight chance
across the southwest and south central seems reasonable. Upper
level shortwave ridging build over the area Saturday in response
to a digging upper trough over southern British Columbia. We will
likely see a little more instability Saturday (1000-1500j/kg cape
from Bismarck to Jamestown via NAM bufkit sounding) but shear will
be minimal. Again it looks like a broadbrush slight chance of
thunderstorms will have to do until we get a little closer in
time. Highs in the mid 70s to lower 80s on Friday will rise into
the upper 70s east to upper 80s west on Saturday.

.LONG TERM...(Sunday through Thursday)
Issued at 350 PM CDT Thu Jul 28 2016

Increasing chances for thunderstorms Sunday into early portions
of next week will highlight the long term period.

Models portraying a closed upper low moving slowly east across
central Alberta Sunday morning with a shortwave ridge developing
across the Northern Plains. At the surface a trough of low
pressure will be in place from Saturday across the high plains,
with an enhanced southerly flow advecting abundant low level
moisture and warmer air into our region. Rich surface dewpoints
well into the 60s and perhaps low 70s will materialize along to
ahead of the trough, along with daytime highs mid 80s east to mid
90s west closer to the thermal ridge. Needless to say we will
realize ample instability during the day Sunday along to ahead of
sfc trough, at this time advertised values of 3-5K J/KG of MUCAPE.
Rather marginal bulk shear values 30-35KTs. Surface trough/cold
front will start to shift east into western ND late Sunday
afternoon, along with increasing mid level divergence behind the
s/wv ridge. This is when convective initialization should occurs
depending on the eventual capping inversion. Both the 12z
GFS/ECMWF are in general agreement with Sunday`s scenario.

Zonal flow on Monday behind the aforementioned upper low as it
continues east-northeast across central Canada coupled with a
building broad ridge across the central plains. Convection
possible southern areas Monday/Monday night. Similar scenario that
we will see Sunday looks to play out again on Tuesday as another
closed upper low moves into the Pacific NW and another S/WV ridge
initially will be over our region Tuesday AM. Only difference
Tuesday compared to Sunday is the closed low takes a slightly more
southerly track.

Northwesterly/zonal flow after Tuesday then followed by broad
ridging towards the following weekend will see generally dry
weather with isolated chances for showers/thunderstorms.
Temperatures under this pattern will begin cooler mid-week, then
warm towards the weekend.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1224 AM CDT Fri Jul 29 2016

Some short term models are depicting MVFR or possible IFR stratus
over parts of mainly southern North Dakota, possibly
impacting KDIK, KBIS and KJMS. However confidence is low due to the
presence of vfr clouds around 4000-7000 feet. Other models indicate
these VFR clouds will linger through sunrise, which would inhibit
low stratus and fog formations. Thus kept VFR except added a tempo
group at KDIK before sunrise - since the western edge of
the VFR clouds is currently over KDIK, it has a better possibility
of clearing out before sunrise, with a dip in temperatures and thus
low stratus/fog formation for up to around 3 hours or so. Otherwise,
VFR conditions are forecast across western and central North Dakota.


.BIS Watches/Warnings/Advisories...


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