Area Forecast Discussion
Issued by NWS Bismarck, ND

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880
FXUS63 KBIS 260308
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1008 PM CDT WED MAY 25 2016

.UPDATE...
Issued at 1003 PM CDT Wed May 25 2016

Looks like the main severe threat has ended for the night with the
convection moving east of the James River Valley. Still an area of
showers and isolated thunder farther west over central ND but
severe potential here has diminished substantially. Also some
showers and isolated thunder over eastern MT that may move into
the west toward midnight. Updated pops based on latest radar
trends. Did add a slight chance of showers in the far west to
cover activity moving in from MT.

UPDATE Issued at 658 PM CDT Wed May 25 2016

Scattered convection continues to spread east across northwest
and central ND. Surface low in eastern ND with a trough into
northwest north dakota toward an upper low over northeast MT. This
scenario is producing a favorable environment for thunderstorm
activity. Over northwest ND the NST parameter was pegged earlier
and there was a funnel cloud reported northwest of plaza. Over the
south central portion of the state more shear and instability
remain with the added forcing of a shortwave moving into the
vicinity. The problem is that we will continue to stabilize as we
move through the evening, and this area saw limited heating during
the daytime. Think the potential for a severe storm still remains
over the south central portion of the state but will continue
diminish as we move into the late evening.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 222 PM CDT Wed May 25 2016

Thunderstorms today highlight the short term.

An upper level low centered over the border of Saskatchewan and
northern Montana is keeping the region in southwest cyclonic flow.
Two upper level short waves can be seen on water vapor satellite
imagery. One is located over central North Dakota and lifting
north. This wave was associated with early morning precipitation
that has now generally moved away from western and central North
Dakota. The second wave is currently located near the southern
Black Hills of South Dakota and is starting to spark off scattered
showers and thunderstorms over much of the western Dakotas.

At the surface, low pressure has propagated north from South
Dakota into southeastern North Dakota with a surface trough
extending northwest across central and western North Dakota.
Breaks in the clouds in the south central and southeast should
help to continue destabilizing the atmosphere through the
atmosphere. Latest guidance and RAP mesoanalysis trends suggest a
large area of 500-1500 J/KG MLCAPE along a line from Bismarck to
Jamestown and south to the state border. Stronger deep layer shear
is vacating the area with the leading short wave. However,
guidance does suggest an environment marginally conducive for non-
supercell tornadoes/landspouts. Strong low level CAPE/steep lapse
rates, elevated surface vorticity associated with the low/trough,
and very little shear could contribute to one or two brief/weak
tornadoes given the stronger cores. Otherwise, expect pulse style
storms with small hail and gusty winds as the main threats given
the weak shear in place.

Overnight, expect continued showers and thunderstorms to wrap
around the low, mainly in the north and west. Chances for
precipitation will continue through Friday.

.LONG TERM...(Friday through Wednesday)
Issued at 222 PM CDT Wed May 25 2016

Persistant southwesterly flow will continue over the area through
the extended period as trough lingers over the western CONUS. This
will bring a daily chance for showers and thunderstorms. The
timing of individual waves lifting through the flow remains
tricky, so will more or less keep broad-brushed chances through
much of the period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1003 PM CDT Wed May 25 2016

Showers and scattered thunderstorms have diminished greatly late
this evening from Williston to Minot and southeast to Bismarck
and Jamestown. Will continue a vcts in JMS for the next hour or
so. Otherwise convection too isolated to carry attim in any one
specific taf. Areas of mvfr ceilings are possible late tonight
into Thursday morning. Chance of thunderstorms again Thursday
afternoon.

&&

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

$$

UPDATE...TWH
SHORT TERM...ZH
LONG TERM...JJS
AVIATION...TWH



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