Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 231529
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1029 AM CDT Wed May 23 2018

.UPDATE...
Issued at 1022 AM CDT Wed May 23 2018

Severe convective potential for this afternoon and evening is
highly conditional on how much sun and surface heating is achieved
through the late morning and into the afternoon. If clouds do
break up and more heating is obtained, a more widespread severe
threat is possible as depicted by the 06 UTC GFS. If cloud cover
remains significant, the threat would be lower as shown by the
CAMs through the 14 UTC HRRR. GOESEast mesoscale sector number 2
is available with one minute imagery across the region. A special
18 or 19Z sounding may be launched, especially if clouds begin to
break up.

UPDATE Issued at 636 AM CDT Wed May 23 2018

While the line of showers and isolated thunderstorms associated
with a warm front continues to diminish as it moves north into
North Dakota, scattered thunderstorms continues to pop up across
west central North Dakota, well to the north of the southern
convection. This may be an outflow boundary from last night, or
more likely the nose of teh expected low level jet. So will add
chance for thunderstorms.

&&

.SHORT TERM...(Today and tonight)
Issued at 329 AM CDT Wed May 23 2018

Short term concerns today include the chance for severe
thunderstorms and the possibility of heavy rainfall. Training
storms Tuesday evening cause some flash flooding across southwest
North Dakota. Since then the storms have ended and the water has
receded across the roads that were impacted in Adams County.

The overall moist weather pattern continues today with PW still
above the the climate percentile. So some concern based on the
PW. NAM/GFS both portray a weak wave on the east side of the upper
trough moving north through the region today. Currently, a line
of showers and weak thunderstorms has formed on this wave and is
propagating north across central South Dakota.

Present indications are the line will move into North Dakota and
diminish in the diurnal minimum morning period. However a robust
low level jet will support regeneration this afternoon and
evening. Storms that form could have heavy rain but will not
issue any flash flood headlines at this time.

However, severe weather is a concern with the max updraft
helicity supporting a severe weather threat across most of west
and central North Dakota by late this afternoon and evening.
Current thinking is hail and damaging winds.

.LONG TERM...(Thursday through Tuesday)
Issued at 329 AM CDT Wed May 23 2018

The extended period calls for warmer temperatures and generally
dry weather Thursday through Sunday, with highs from the mid 80s
to around 90. After Sunday however this could also be an active
weather pattern as an upper low over the western US is in a
position to send shortwaves northeast into the northern plains.
Cooler temperatures with more normal highs in the 70s to lower 80s
are forecast monday through Tuesday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday)
Issued at 1022 AM CDT Wed May 23 2018

Isolated rain showers and thunderstorms this morning may increase
in coverage and severity late this afternoon and evening across
western and central North Dakota. However, uncertainty in
thunderstorm coverage this afternoon and evening remains high.
Other than scattered MVFR stratus decks across the southwest
today, VFR conditions outside of thunderstorms are expected.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...PA
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...PA



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