Area Forecast Discussion
Issued by NWS Bismarck, ND

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694
FXUS63 KBIS 282338
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
638 PM CDT SUN AUG 28 2016

.UPDATE...
Issued at 631 PM CDT Sun Aug 28 2016

Storms continue to develop over southwest Manitoba near the
international border along a boundary that sweeps southwestward
into north central North Dakota. A few storms may develop this
evening a bit further south into our area, though so far they are
staying further north. To the south, storms are starting to
develop over northeast South Dakota along a surface trough, with
cumulus development stretching northward near the state line. With
strong instability in place, would not be surprised to see a storm
or two develop over our far southeastern areas. Therefore, have
added some low chances for thunderstorms over the next few hours.
Updates have been sent.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 238 PM CDT Sun Aug 28 2016

Possible thunderstorms in the far east highlight the short term
period.

Very warm conditions exist across western and central North Dakota
this Sunday afternoon, ahead a cold front that is just pushing
into the northwest part of the state. Temperatures are mainly in
the mid 80s to mid 90s behind a warm front that has pushed through
western and into central ND. Over western ND dewpoints are
currently in the upper 30s to mid 40s. This is producing relative
humidities of 10 to 15 percent over portions of west central and
southwest ND. Behind the cold front which is now moving through
the northwest, there is a temporary increase in clouds and
slightly higher humidities with some slightly higher winds with
gusts around 20 mph. We could see near critical to critical fire
weather conditions for a couple hours this afternoon in the far
west but do not think conditions will be widespread enough and
over a long enough period to warrant a Red Flag Warning.

Farther to the east, mainly along and east of the Highway 83
corridor, dewpoints remain in the mid 60s to lower 70s. Atmosphere
has become quite unstable over this area during the past hour or
two. Latest iterations of Convective allowing Models continue to
indicate the greatest threat for severe weather to remain just
east of the forecast area. However, two areas of concern will be
the far northeast and far southeast CWA, each where CAMS indicate
Reflectivity signatures with supercellular characteristics. Will
certainly need to monitor given the proximity to our CWA. Even if
this would brush our CWA it would be a limited duration event
early this evening, with most of the convection to our east.

Cold front moves through the area tonight with near zonal flow
over the area late tonight through Monday. NAM/GFS are indicating
some weak shortwave energy moving through the zonal flow and
producing some weak qpf amounts behind the cold front Monday. Have
increased the cloud cover due to the increased moisture in the mid
levels noted from WV imagery, but will leave out any mention of
precipitation at this time. Any amounts would be mainly trace to a
hundredth or two. Cooler on Monday with highs from the mid 70s
north to mid 80s south.

Surface high pressure moves east of the area by Tuesday and we
warm back into the upper 70s to mid 80s Tuesday and Wednesday.
Models are inconsistent with the possibility of showers and
thunderstorms spreading west to east Tuesday into Wednesday with
the return of a low level jet. We have been carrying some mainly
slight chance pops and will continue this trend. GFS is most
vigorous with NAM/EC not as robust. A blend still brings some
slight chance pops.

.LONG TERM...(Thursday through Sunday)
Issued at 238 PM CDT Sun Aug 28 2016

Warm weather with above seasonal normal temperatures will continue
into the longer term of the forecast, through Saturday of the Labor
Day Holiday Weekend, before cooler weather moves in for Sunday and
Labor Day. There will be chances for thunderstorms as well with the
highest chances later Friday into Saturday, then again during the
day on Monday.

A deepening trough on the west coast advances toward the Northern
Plains with increasing southwest mid level flow. A lee side surface
trough brings moist southerly flow back in with increasing
instability and the chances for scattered storms increasing to end
the week and begin the long weekend. A cold front brings an end, for
now, to the 80s plus temperatures of this week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 631 PM CDT Sun Aug 28 2016

Isolated thunderstorms possible this evening over portions of far
north central North Dakota and the far southern James River
Valley. Otherwise, VFR conditions are expected.

&&

.BIS Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...JJS
SHORT TERM...TWH
LONG TERM...JPM
AVIATION...JJS



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