Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 300530

Area Forecast Discussion
National Weather Service Bismarck ND
1230 AM CDT SAT JUL 30 2016

Issued at 1230 AM CDT Sat Jul 30 2016

The latest iterations of high res CAM models continue to depict
isolated showers and thunderstorms during the early morning hours,
mainly in central North Dakota. Latest mesoscale analysis indicates
a low level jet over the western Dakotas...with the h850 northern
extent reaching north of the I-94 corridor. Isolated late
evening/early morning thunderstorms developed in this vicinity over
Mercer/Dunn counties. Mixed layer CAPE was present at about 1000
J/kg, which helped initiate the storms along the nose of the low
level jet. However, mid level lapse rates were quite low - on the
order of around 5.5 C/km. Downdraft CAPE is also fairly low at
around 600 J/kg. This is likely why the storms did not reach severe
levels, and why we do not expect large hail or damaging winds this
morning. Given the position of the low level jet in the west, we
kept a slight chance mention of thunderstorms in parts of western
North Dakota this morning. Otherwise, blended current observed
temperature/dewpoint/winds this update.

UPDATE Issued at 935 PM CDT Fri Jul 29 2016

Other than to blend to observed trends through 02 UTC, the
forecast remains relatively unchanged. The 23-01 UTC HRRR/HRRRX
continue to suggest isolated elevated convection late tonight into
Saturday morning south central and east with a weak low level jet
aided by a mid level shortwave and increasing moisture transport.
Severe weather is not expected.

UPDATE Issued at 635 PM CDT Fri Jul 29 2016

No significant changes with this update other than to blend to
observed trends through 23 UTC. Overall, shower and thunderstorm
coverage has decreased over the past one to two hours across
central North Dakota. However, given plentiful outflow boundaries,
the potential for weak funnel clouds continues through sunset.
Additional elevated storms are possible south central and into the
James River Valley late tonight aided by the interaction of a weak
low level jet and mid level shortwave. Severe weather is not


.SHORT TERM...(Today through Sunday)

Issued at 300 PM CDT Fri Jul 29 2016

Forecast highlights in the short term period will be increasing
chances for thunderstorms along with a warming trend into the
weekend. Severe storms possible Sunday and Sunday night.

Currently, the aerial coverage of showers and/or thunderstorms
continues to increase this afternoon, with isolated activity now
stretching father north across central ND. This activity is
concentrated along an axis of instability east of a subtle surface
low, and ahead of a decent mid level shortwave trough moving
southeast into the Northern Plains. Extensive CU field continues
over much of western ND, though high res models now mostly dry
there and this area also void of any radar returns, so have scaled
back on pops west. Bulk shear parameters in addition to mid level
lapse rates should keep all activity well below severe thresholds
through tonight with short-lived single cell thunderstorms.

Greatest coverage and chances for showers and/or thunderstorms
will continue to be over the south central and into the James
River Valley this evening before diminishing chances overnight
but not entirely ending.

For Saturday, warmer air and increasing moisture across the region
with an increasing southerly return flow. Highs generally in the
80s most areas. Chance for thunderstorms mainly over my east on
Saturday underneath an instability axis and collocated with the
better boundary layer moisture, though weaker mid level forcing
as we are seeing today so kept chances in the slight category.

Models portraying a closed upper low moving slowly east across
central Alberta Sunday morning with a shortwave ridge developing
across the Northern Plains. At the surface a trough of low
pressure will be in place from Saturday across the high plains,
though the southerly return flow should increase helping to
advect additional low level moisture and even warmer air into our
region. Rich surface dewpoints well into the 60s and perhaps low
70s will materialize along to ahead of the trough, especially
across the central and eastern portions of the state. Daytime
highs mid 80s east to mid/upper 90s west closer to the thermal
ridge. Needless to say we will realize ample instability during
the day Sunday with the expected heat and humidity along to ahead
of the sfc trough which is expected to be near the MT/ND border
area by 18Z Sunday. At this time models still advertise values of
3-5K J/KG of MUCAPE with rather marginal bulk shear values of
30-35KTs. Surface trough/cold front will start to shift east into
western ND mid-late Sunday afternoon, along with increasing mid
level divergence behind the s/wv ridge as our flow becomes more
southwesterly. Convective initialization expected once forcing
and/or surface heating overcomes the capping inversion, which
appears to range from late afternoon/early evening. Strong to
severe convection expected to then expand east Sunday evening
before pushing out or ending overnight into Monday morning. Will
continue to mention the possible severe in the HWO.

.LONG TERM...(Monday through Friday)
Issued at 228 PM CDT Fri Jul 29 2016

Active cyclonic flow will remain over the area on Monday, with
thunderstorms expected to develop to the east of a boundary
draped through central North Dakota. Chances continue into the
evening as storms gradually push east. Temperatures will be milder
behind the boundary.

Compact upper low digs through the Pacific Northwest and crosses
the Rockies near the international border early Wednesday before
it opens up as it ejects into the plains Wednesday afternoon,
bringing additional thunderstorm chances.

Weak upper ridging will bring drier conditions to end the work


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1230 AM CDT Sat Jul 30 2016

North Dakota remains under the influence of a weak trough aloft that
will support widely scattered thunderstorms across central and
eastern north dakota through Saturday. This area between KBIS-KJMS.
At this time storms are to widely scattered and uncertain to mention
in TAFS. Otherwise VFR conditions are expected.


.BIS Watches/Warnings/Advisories...


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