Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 160258

Area Forecast Discussion
National Weather Service Bismarck ND
958 PM CDT Tue Aug 15 2017

Issued at 946 PM CDT Tue Aug 15 2017

Showers were moving off to the east this evening with surface
high pressure building from the west. Biggest adjustment this
update was the extension of overnight patchy fog into the west,
due to the influx of surface moisture from today`s rains aligned
with mid-level ridging. Otherwise no other major changes were

UPDATE Issued at 645 PM CDT Tue Aug 15 2017

Precipitation continues for much of central North Dakota with
scattered showers to the west. A few thunderstorms were moving
through our far northwest in an area of marginal CAPE and weak
shear. Would expect these to stay sub-severe tonight. Ongoing
forecast looks good with showers tapering off from west to east
through the overnight hours.


.SHORT TERM...(This evening through Wednesday)
Issued at 311 PM CDT Tue Aug 15 2017

Showers, and maybe an embedded thunderstorm spread across the area
this afternoon and tonight, then we dry out on Wednesday.

Latest surface analysis shows low pressure extending from the
western portions of the central plains northward into the western
Dakotas. Upper level analysis shows a broad upper trough over
western U.S and Canada with circulations over Saskatchewan and the
Desert southwest, with another digging shortwave trough dropping
down the Pacific west coast. Closer to home, a broad southwest
flow remains from the central high plains into the northern
plains. Numerous impulses tracking through the flow are producing
showers and thunderstorms, with the strongest activity over
Nebraska and western Iowa.

In western and central ND, widespread showers extend from western
Grant and Sioux counties, north northeast to southern Ward
county, with another smaller area from central SD to around Linton
in south central ND, tracking east northeast. The highest rain
totals are expected to track from just west of Bismarck Mandan,
into the Turtle Mountains and the Devils lake Basin. High PWATs
(1.50-1.75in) advect from central ND into the James River Valley
during the late afternoon and evening. With limited CAPE it
remains to be seen if we develop any thunder over the southern
JRV, where we had heavy rain this past weekend. HPC continues a
marginal risk of excessive rain over southeast ND, including the
JRV. Convection allowing models are mixed in their solutions of
convection over the JRV through the evening and point toward
areas south of the ND border to having the best risk of Thunder.
Will continue to monitor but at this time will not add any
additional wording for heavy rain.

One additional area for possible thunder late this afternoon or
early evening would be the far northwest. with drier air moving
in, the threat of severe storms here seems minimal. NAM/HRRR
Bufkit soundings do indicate a few hours of weak CAPE with around
20 knots of bulk shear this evening.

Showers taper over western and central ND this evening, and
lingers over the far southern JRV into Wednesday morning.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 311 PM CDT Tue Aug 15 2017

Warmer and drier weather in the long term period

An upper level ridge is expected to push in by the end of the week.
Generally, Wednesday and Thursday appear dry. A shortwave trough
drops through the area on Thursday night and Friday bringing a
small chance of showers and thunderstorms northwest to southeast
across the area. Then another slight chance of storms Sunday.
After highs in the 70s Wednesday, daytime highs are expected to be
mainly in the low to mid 80s Thursday through Tuesday.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 645 PM CDT Tue Aug 15 2017

MVFR and IFR ceilings continue in areas of precipitation, with
precipitation ending from west to east through the evening. MVFR
and some IFR ceilings will expand and linger for much of North
Dakota tonight, with the western edge under the fringes of the
stratus deck. MVFR visibilities will occur overnight with patchy
fog possible for all terminals.




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