Area Forecast Discussion
Issued by NWS Bismarck, ND

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487
FXUS63 KBIS 301531
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1031 AM CDT SAT JUL 30 2016

.UPDATE...
Issued at 1027 AM CDT Sat Jul 30 2016

Small area of precipitation continues to push east through south
central North Dakota into portions of the James River Valley.
Overall intensity has diminished, though every now and then an
individual cell strengthens a bit. Expect this to continue to move
east. Still expect additional precipitation to develop later today
as the next short wave moves through with weak cyclonic flow over
the area, though this will be very hit-and-miss and do not expect
heavy precipitation to develop from the afternoon convection.

UPDATE Issued at 735 AM CDT Sat Jul 30 2016

Have sent out a quick update to address the latest trend on
compact area of thunderstorms moving through south central North
Dakota into the James River Valley. Storms continue to produce
locally heavy rainfall with radar indicating a swath of around one to
two inches and possibly a bit more falling from the storms to the
northeast of Bismarck. Expect these storms to continue their east-
northeast progression though should slowly dissipate as they move
into an area of very weak instability. Further west, have added
the mention of patchy fog for portions of western into north
central North Dakota based on latest observations and webcams. Fog
should dissipate by mid-morning.

UPDATE Issued at 541 AM CDT Sat Jul 30 2016

This update to focus on heavy rain from some thunderstorms in
south central North Dakota through 8 am. No current flood
advisories in effect at this time but some areas may get 2 to 3
inches of rain from the heavier storms.

&&

.SHORT TERM...(Today through Sunday night)
Issued at 323 AM CDT Sat Jul 30 2016

Forecast highlights in the short term period will be increasing
chances for thunderstorms, a warming trend, and increasing humidity
this weekend. Severe storms are possible Sunday and Sunday night.

Currently, isolated to scattered showers and thunderstorms
continued early this morning over central ND. This convection was
associated with a southerly low level jet over the western plains,
and a weak mid level shortwave that continues to progress eastward
across the region. The h925-h850 northern extent of the low level
jet reached into central ND. This was fueling the initiation of the
convection. Mixed layer CAPE had waned over the past few hours, but
continued at around 500 J/kg. Mid level lapse rates were low as
well, thus the threat of severe storms is low.

Later today, another weak mid level impulse moves east across
western and central ND.  Surface high pressure over the Great Lakes
area and general low pressure over the Rockies will keep a southerly
low level flow across the region, and expect to keep dewpoints in
the 50s western ND to lower 60s central ND. This will keep small
chances of thunderstorms over mainly eastern portions of central ND
in the region of higher dewpoints. Expect highs today ranging from
the lower 80s east to upper 80s southwest.

The models continue to depict an upper level trough over British
Columbia today, becoming a closed low tonight as it tracks east into
Alberta, then continues to strengthen over central
Alberta/Saskatchewan Sunday and Sunday night.

Tonight as the upper trough approaches ND, the low level jet
strengthens, and a mid level thermal ridge builds from Wyoming into
the western Dakotas and Montana. Meanwhile leading upper level
impulses ejecting out ahead of the low/trough system move east
across the state. Models are indicating that scattered to isolated
thunderstorms are possible mainly over eastern parts of central ND
east of the mid level thermal ridge.

On Sunday the low level jet and mid level ridge continue to
strengthen and push northward well into central Canada. Looking at
high temperatures in the mid 90s southwest to the lower 90s in much
of central ND, with mid 80s in the Turtle Mountains and James
Valley. Surface dewpoints over ND rise well into the 60s, perhaps
into the lower 70s in some areas. Sunday afternoon a north-south
oriented surface trough enters western ND, accompanied by an upper
level shortwave impulse, and should be the focus of thunderstorm
initiation over western ND. These features continue eastward across
the state Sunday night. CAPE values should reach 3500-5000 J/kg with
0-6 km bulk shear 40-45 knots. The Storm Prediction Center continues
to indicate a marginal risk of severe thunderstorms - mainly because
the best overall pressure height falls and large-scale ascent will
be over southern Canada.

Will continue to mention possible severe thunderstorms in the
Hazardous Weather Outlook.

.LONG TERM...(Monday through Friday)
Issued at 323 AM CDT Sat Jul 30 2016

A progressive pattern will continue in the extended with lingering
thunderstorms remaining across central North Dakota Monday afternoon
as a northeast to southwest oriented cold front sweeps through the
area. Plenty of shear will be available and enough cape remains in
place to support perhaps another line of thunderstorms through the
Missouri river valley into the James river valley Monday afternoon
and evening.

On Tuesday surface high pressure will build into the region leaving
the area mainly dry except for some late afternoon/evening
thunderstorms far west. These storms will be supported by the next
upper wave that will bring better chances for thunderstorms Tuesday
night into Wednesday.

Thursday through Saturday will see generally dry weather with
temperatures about normal.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 541 AM CDT Sat Jul 30 2016

North Dakota remains under the influence of a weak trough aloft that
will support scattered thunderstorms across central and eastern
north dakota through Saturday. This area between KBIS-KJMS. Patchy
areas of fog are possible KDIK-KBIS til 15z. Otherwise VFR
conditions are expected.


&&

.BIS Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...JJS
SHORT TERM...JV
LONG TERM...WAA
AVIATION...WAA



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