Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 192259

Area Forecast Discussion
National Weather Service Bismarck ND
559 PM CDT Wed Jul 19 2017

Issued at 559 PM CDT Wed Jul 19 2017

After collaborating with neighboring offices, decided to decrease
POPS to non-measurable southern James River Valley. Latest
visible imagery shows little in the way of cloud development. Per
SPC mesoanalysis page, surface CIN, as well as ML Cin already in
place. Despite strong shear aloft and departing jet, not expecting
any further development this evening. Did keep a slight chance
mention in the northwest with a shallow cumulus field in place
through 00z/7pm. Rest of forecast on track tonight, with dry
conditions expected.


.SHORT TERM...(This afternoon through tonight)
Issued at 315 PM CDT Wed Jul 19 2017

Current surface analysis places low to the south of the Black
Hills, with secondary trough moving through Manitoba stretching
into North Dakota. Upper level analysis places high over the
southern plains with monsoonal moisture wrapping over the system.
Over our area, a generally western active pattern is in place with
a variety of weak waves moving through.

For the rest of this afternoon into tonight...most convective
activity has pushed to the south and east of the area, though with
aforementioned waves sliding through the flow, an occasional
shower or storm may pop up either over the southeastern portions
of the area where ample instability is noted, or over the
northwest where a bit more notable wave will be approaching.
Confidence has lessened on severe threat over the southeastern
portions of the area as instability is not as strong as previously
noted, but still high enough to keep a close eye on the area.

.LONG TERM...(Thursday through Wednesday)
Issued at 315 PM CDT Wed Jul 19 2017

An active and seasonably warm pattern will continue through much
of the long term on the northern edge of the large, but flattened
subtropical ridge. Two primary opportunities for thunderstorms may
be Thursday afternoon into Thursday night in western ND, and
across central ND from Thursday night into Friday. Initially, it
appears that elevated instability may favor convective sustenance
out of eastern MT Thursday night, fed by a modest low-level jet.
A greater opportunity for more robust, surface-based storms with
an attendant greater probability of severe weather may develop
Friday afternoon and evening across central ND ahead of a cold
front. Latest Nam is still showing the potential for cape values
of 2.5-4 kJ/kg over central North Dakota with 40kts of 0-6 kg bulk
shear (GFS showing similar values but is a tad bit further west
with instability axis), though there are questions about frontal
timing and the potential for capping to limit convective coverage.

Otherwise, a drier and cooler post-frontal air mass may invade the
region for the weekend before a warming trend returns next week.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 559 PM CDT Wed Jul 19 2017

Tranquil weather conditions expected until 18z Thursday. Then
isolated to scattered showers and thunderstorms will develop
across the western and north central terminals KDIK/KISN/KMOT.
Precipitation possible at KBIS/KJMS after 00Z Friday. Vfr
cigs/vsbys expected through the period.




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