Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 250806

Area Forecast Discussion
National Weather Service Bismarck ND
306 AM CDT SAT JUN 25 2016

Issued at 304 AM CDT Sat Jun 25 2016

Update to remove remaining counties from Severe Thunderstorm Watch
297, which completely ends our severe thunderstorm watch across
western and central ND. Updates to text products forthcoming.

UPDATE Issued at 150 AM CDT Sat Jun 25 2016

Update to cancel part of Severe Thunderstorm Watch 297 west of a
Minot to Bismarck line.

UPDATE Issued at 106 AM CDT Sat Jun 25 2016

Severe thunderstorm watch 296 for western North Dakota has
expired. Thunderstorms will continue central and east with the
strongest storms north central through sunrise. Wake low winds
with gusts to 50 mph have been an issue northwest but are now
diminishing slowly. Will continue to evaluate over the next few
hours. Increasing gradient winds are still expected southwest and
south central Saturday where a wind advisory continues.

UPDATE Issued at 1035 PM CDT Fri Jun 24 2016

Quick update to extended Severe Thunderstorm Watch 296 into
far southwest North Dakota until 06 UTC and to issue Severe
Thunderstorm Watch 297 through 10 UTC across much of central North
Dakota ahead of the strong linear complex across northwest North
Dakota. Strong pressure perturbations associated with this
complex may help to force more scattered convection to the south
into southwest and south central North Dakota. This more scattered
convection currently across southwest North Dakota is moving into
a more unstable environment closer to the moisture axis across
central North Dakota with strong deep layer effective shear. While
uncertainty about the evolution of this convection remains, a
sufficient severe threat exists per coordination with SPC to
include the Bismarck, Mandan and Jamestown areas.

UPDATE Issued at 821 PM CDT Fri Jun 24 2016

Update to adjust pops to the latest observed radar trends through
01 UTC, and the 21-00 UTC HRRR/HRRRX which have well assimilated
the linear complex across northeast Montana. Expect the line to
cross into northwest North Dakota between 0230-0300 UTC. See SPC
MCD #1048 for details regarding the large hail and damaging wind
threat with this complex. It should also be noted as this complex
enters a more moisture rich environment across northwest North
Dakota, LCLs do lower with around 150 m2/s2 of 0-1km helicity and
15 kts of 0-1km shear. This would support a possible tornado
threat, especially with any discrete segment of the overall
complex. Still some uncertainty across southwest North Dakota
where convective coverage will be lower, however, isolated
convection across southeast Montana that has had a hard time
maintaining itself will be encountering a more supportive
environment for organization in North Dakota.

UPDATE Issued at 528 PM CDT Fri Jun 24 2016

Quick update to issue severe thunderstorm watch 296 for much of
western North Dakota valid through 06 UTC. An extension of the
watch into the north central may be needed later this evening per
trends in the 18-21 UTC CAM suites. Overall, it will likely be
another 3-4 hours for convection to propagate into western North
Dakota from Montana with strong upper level forcing ahead of the
deep upper level low complemented by the surface cold front.
Across the central, while the 21 UTC RAP suggests an uncapped
environment with strong convective parameters spaces, forcing is
weak and the scenario suggested in the operational HRRR of
initiating strong convection, while a non-zero threat, is not
supported by the greater CAM suite.


.SHORT TERM...(This evening through Saturday)
Issued at 333 PM CDT Fri Jun 24 2016

The main highlights for the short term forecast include strong to
severe storms this evening west and widespread late tonight...then
strong westerly winds on Saturday.

The surface low center was near Hettinger/Black Hills SD this
afternoon. Southeasterly winds ahead of the low continued to advect
low level moisture into our region...with surface dewpoints well
into the mid 60s and lower 70s across central and into northwestern
North Dakota. Low level instability continued to increase with
surface based CAPE values of 1500-2500 J/Kg...but CIN values of 50-
100 J/Kg reflect the well established strong thermal cap. Latest
meso analysis suggests H700 temperatures of +14C in southwestern
North Dakota and +10 over northern North Dakota. This cap should
continue through the afternoon, which should inhibit convection.
Some models suggest no convection this afternoon in North
Dakota...while a couple models still suggest some convection at the
boundary between the western edge of the low level jet, the surface
dewpoint boundary between lower 60s southwest and upper 60s/70s to
the east and north. The area in question would be mainly east of
Bismarck to the James Valley and northward towards the Turtle
Mountains and Devils Lake basin. Thus will keep the slight chance
mention of afternoon thunderstorms in the Turtle Mountains area but
also bring the slight mention farther south into the
Stutsman/Logan/LaMoure area for late afternoon.

Tonight all models are in good agreement regarding thunderstorms
developing in central Montana late this afternoon/evening...and
moving into far western North Dakota around 8 pm mdt/9 pm
cdt...spreading into central North Dakota after midnight, with
scattered thunderstorms lingering in central North Dakota Saturday
morning. High res and synoptic models agree that the best chance for
severe storms will be this evening and in the early morning hours -
mainly over western and north central North Dakota. The more
widespread thunderstorms are still expected to be mainly north of I-

This convection is associated with the large upper level impulses
out ahead of the main upper low, which is progged to be centered
over southwestern Saskatchewan daybreak Saturday morning, and moving
east into southern Manitoba by Saturday evening.

As the associated cold front enters western North Dakota after
midnight, strong west/northwest winds will initially push into the
southwest part of the state. Wind speeds of 30 mph with gusts to 40
mph are possible behind the front and especially if enhanced by
thunderstorms. There may be a lull in wind speeds around daybreak,
but winds should pick back up late morning as surface winds link
with winds aloft around 40-45 knots at H850. Expect winds may link
up to H700 at times. Issuing a wind advisory for the far southwest
beginning around 3 am mdt...and for the rest of the area along and
south/west of the Missouri River...including Lake Sakakawea.

.LONG TERM...(Saturday night through Friday)
Issued at 333 PM CDT Fri Jun 24 2016

Main upper level low continues to move east into southwestern
Ontario by Sunday evening. Gusty west winds expected to continue on
Sunday...but not as strong as Saturday. Lingering showers and
thunderstorms are expected across the north but the bigger impacts
are expected from wind behind the system.  High temps from Sunday
through Tuesday will be mainly in the 70s, with a gradual warm up by
mid-week to the 80s. There is still a chance of thunderstorms
Tuesday night and Wednesday with the long range models depicting a
shortwave moving through the northwest flow aloft.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 106 AM CDT Sat Jun 25 2016

Hazards to aviation continue with thunderstorms and gusty winds
the issue. A line of thunderstorms associated with an eastward
moving cold front will impact KBIS-KMOT-KJMS through 10z...then
clearing. Gusty northwest winds 25 to 35kts KDIK-KBIS will develop
after 12z. VFR expected.


.BIS Watches/Warnings/Advisories...
Wind Advisory from 10 AM CDT /9 AM MDT/ this morning to 7 PM CDT
/6 PM MDT/ this evening for NDZ017>021-031>034-042-045.

Wind Advisory until 6 PM MDT this evening for NDZ040-041-043-044.



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