Area Forecast Discussion
Issued by NWS Bismarck, ND

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
548
FXUS63 KBIS 250229
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
929 PM CDT Thu May 24 2018

.UPDATE...
Issued at 928 PM CDT Thu May 24 2018

The threat of thunderstorms - especially strong storms - in western
and central North Dakota has decreased. The surface cold front has
moved east of the Turtle Mountains and James Valley, and was over
the Red River Valley. Drier air and westerly winds had encompassed
all of western and central North Dakota, and any severe weather
parameters has moved out of our area.

However, some isolated showers and thunderstorms lingered in the
vicinity of the upper level low centered over central and southern
Saskatchewan/Manitoba. This would include northwestern and north
central North Dakota. The latest iterations of the high res models
indicate this convection should wane through the evening hours.

Current forecast on track with winds and temperatures for tonight.

UPDATE Issued at 634 PM CDT Thu May 24 2018

Concerns this update is for thunderstorm potential.

Currently, an upper level low was over Alberta/Saskatchewan, with a
shortwave ahead of the low over the Sask/Man/ND border which was
lifting northeastward into Manitoba/Saskatchewan. Scattered showers
and thunderstorms developed this afternoon in northwestern and north
central ND, with most of the forcing associated with the shortwave
lifting north of the international border. A few isolated
showers/thunderstorms lingered in northwestern and north central ND,
and will likely remain isolated into early this evening...waning by
sunset.

In eastern North Dakota, a surface cold front out ahead of but
associated with the large upper low in Canada extended from south
central Manitoba across the Turtle Mountains and James Valley and
into central South Dakota. There is a potential for convection along
this boundary, but it appears that the best forcing for this is in
South Dakota. As the front moves east this evening, the threat for
the James Valley wanes early, moving into the Red River Valley for
the evening hours. This is confirmed with current radar loops and
satellite pics, showing agitated convection in south central and
southeastern South Dakota. Thus, while it is still possible for the
northern James Valley to see thunderstorms, the threat is low and likely
be confined to the very early evening hours.

&&

.SHORT TERM...(This evening through Friday)
Issued at 128 PM CDT Thu May 24 2018

The main focus for the short term is thunderstorms (and potential
severe thunderstorms) late this afternoon and evening.

An upper level shortwave is currently moving across North Dakota
this afternoon. An accompanying cold front is currently
stretched along western North Dakota. Most short-term models
depict scattered showers and thunderstorms across northern North
Dakota near the center of the upper level low with very little if
any convection along the cold front through the afternoon. The
cold front will likely light up later this evening, but by then it
should be about out of our area and entering eastern North
Dakota.

Instability and shear are less than expected this afternoon across
most of the area. Better moisture/shear profiles are present
further east. This should limit the severe threat to the far
eastern James Valley (location of best moisture) and the Turtle
Mountains (location of greatest forcing). Hail up to an inch and
strong winds up to 60 mph are possible in the strongest storms.

Tomorrow...the warm up begins. Westerly warm air advection and a
building upper level ridge will lead to temperatures in the upper
80s to low 90s. Breezy winds and low humidity may lead to fire
weather concerns, however, most locations are quite green at this
time so that may reduce the critical fire danger threat.

.LONG TERM...(Friday night through Thursday)
Issued at 128 PM CDT Thu May 24 2018

This weekend will be quite warm, with some locations approaching
their record high temperatures. With an upper level ridge building
in and either a combo of downsloping winds or compressional
warming we will likely see widespread temperatures in the low 90s
by Saturday.

The upper level ridge begins to break down Sunday as an upper
level low builds in over the mountain west. This low will remain
nearly stationary Sunday through Tuesday. As a result we will see
cooler temperatures and the chance for widespread showers and
thunderstorms Sunday through Tuesday. The rest of the week looks
rather active with chances for showers and thunderstorms nearly
every day.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 634 PM CDT Thu May 24 2018

VFR at all TAF sites through the TAF period. Isolated showers and
thunderstorms may impact KISN and KMOT this evening with ongoing
isolated convection in northwestern and north central North Dakota.
A slight chance of showers or thunderstorms possible for KJMS as
well, but confidence is low regarding formation of convection at or
very near the KJMS TAF site. Otherwise VFR conditions expected, with
west to southwesterly winds behind the cold front. VFR overnight and
on Friday with westerly winds around 10-15 knots on Friday.


&&

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

$$

UPDATE...JV
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...JV



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.