Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 262030

Area Forecast Discussion
National Weather Service Bismarck ND
330 PM CDT Wed Jul 26 2017

.SHORT TERM...(This evening through Thursday)
Issued at 230 PM CDT Wed Jul 26 2017

Surface analysis shows high pressure centered over the southern
Saskatchewan/Manitoba border, bringing sunshine with a few fair
weather cumulus clouds and calm winds to the state. Further
upstream several upper level impulses depicted on water vapor
imagery over Idaho and Nevada were causing surface pressure to
fall over central Montana. A corridor of meager high based
instability was present in southeastern Montana, possibly into far
southwestern North Dakota, aided by dew points that managed to
reach into the low 50s. With the majority of the dynamic forcing
still upstream and the weak instability profiles, several
convection-allowing model runs have still managed to squeeze out a
few signs of thunderstorm activity in our far southwest. Given
the wide low level dew point depressions and lack of a steep lapse
rate overlay, thunderstorm threats will mainly stick to gusty
winds. Into the overnight hours a secondary chance of elevated
convection is possible on a strengthening low level jet over the
western half of the state, though not expecting many strong
storms with this activity.

On Thursday a brief period of southerly return flow through the
west will allow for at least somewhat of a CAPE/shear profile
possible for convective activity ahead of mid-level shortwave.
While model consensus shows that CAPE values will struggle to
reach 1000 J/kg, deep layer shear values up to 30-40 kts in the
southwest will bring a marginal chance of severe weather.

.LONG TERM...(Thursday night through Wednesday)
Issued at 230 PM CDT Wed Jul 26 2017

Early Friday the second 700mb wave arrives from the west bringing
another chance of showers and thunderstorms for the far west,
especially on the nose of an early morning 850mb low level jet.
Chances for convection will continue into the Friday evening hours
as the surface trough axis shifts from west to east, however
likelihood of severe weather will depend on atmospheric recovery
behind the earlier convective activity.

Going into this weekend the upper level ridge builds once again
keeping the area dry with highs into the 80s and a few spots in
the low 90s. GFS/ECMWF agreement indicates the upper level ridge
shifting off to the east by the beginning of next week, marking
the next chance for precipitation.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 230 PM CDT Wed Jul 26 2017

VFR conditions are expected through the TAF period. There is a
slight chance of thunderstorms this evening across southwestern
North Dakota, but confidence in those storms impacting KDIK is not
high enough to mention in the TAF.




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