Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 230550
AFDBIS

AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1250 AM CDT MON MAY 23 2016

.UPDATE...
Issued at 1250 AM CDT Mon May 23 2016

We will let the remainder of the severe thunderstorm watch expire
as scheduled at 06 UTC. A few thunderstorms are continuing across
the southern James River Valley as of 0545 UTC, but instability is
waning due to both nocturnal boundary layer cooling and convective
overturning, which has greatly decreased the severe storm risk.
Locally heavy rainfall will be the main concern over the southern
James River Valley the next few hours.

Otherwise, we did adjust the chance of precipitation and the rest
of the hourly forecast elements overnight using a blend of recent
high-resolution model guidance.

UPDATE Issued at 1139 PM CDT Sun May 22 2016

We just made another quick update to remove one more row of
counties from the severe thunderstorm watch...including Burleigh
County. Thus, Bismarck is no longer in the watch.

UPDATE Issued at 1040 PM CDT Sun May 22 2016

Quick update to cancel the western parts of severe thunderstorm
watch 192. The effective cold front, which has been partly re-
inforced by storm outflow, has moved east of a Minot to Fort
Yates line as of 0330 UTC. The severe threat has ended west of
the front. We are maintaining the watch east of there for now
given modest instability and moderate to strong deep-layer shear,
but radar trends suggest the severe threat is marginal.

UPDATE Issued at 859 PM CDT Sun May 22 2016

MODERATE INSTABILITY REMAINS OVER CENTRAL INTO EASTERN NORTH
DAKOTA ALONG WITH SUFFICIENT DEEP LAYER SHEAR TO RESULT IN A
CONTINUED SEVERE THREAT AHEAD OF A COLD FRONT DROPPING THROUGH
CENTRAL NORTH DAKOTA. STORMS HAVE HAD TROUBLE BECOMING VERY
STRONG...THOUGH HAVE HAD REPORTS OF PROLIFIC SMALLER HAIL
PRODUCING STORMS ALONG WITH HEAVIER RAIN PRODUCERS OVER THE JAMES
RIVER VALLEY REGION WHERE HIGHEST PRECIPITABLE WATER VALUES WERE
NOTED. SOME POST FRONTAL STORMS ALSO CONTINUE TO DEVELOP WHICH MAY
BE SPAWNED BY AN UPPER LEVEL JET STREAK LIFTING THROUGH THE
REGION. WILL KEEP CURRENT SEVERE WATCH IN TACT.

UPDATE Issued at 605 PM CDT Sun May 22 2016

Thunderstorms are starting to develop over western into south
central North Dakota. Stage is still set with increased
instability and sufficient deep layer shear to support severe
storms with large hail and damaging wind gusts as the main
threats. Plenty of moisture continues to surge in ahead of
gradually progressing cold front (dewpoints in the lower 60s) to
bring the risk of heavy rainfall from some storms. The area with
the greatest risk for this continues to be over south central
North Dakota into the James River Valley.

&&

.SHORT TERM...(This evening through Monday)
Issued at 206 PM CDT Sun May 22 2016

Severe thunderstorms highlight the short term period

The latest water vapor imagery shows a closed low circulating
over Alberta with a 100kt jet streak stretched out from northeast
Montana into central Wyoming. This jet streak nudges east into
western North Dakota this evening. This will provide large scale
ascent along a cold frontal boundary, now located from Portal to
Stanley, and south into Hettinger. Dewpoints in the west are in
the lower 40s while in central North Dakota moisture is higher
with dewpoints near 60F. The cold front will slowly move east
tonight, exiting the James River Valley between 09z-12z Monday.

Visible imagery showing stratus eroding which will initiate and
increase low level buoyancy and instability. The HRRR and NAM look
to have a good trend with convection initiation. The most intense
cells begin near Lemmon SD and develop within a corridor between
Dickinson and Bismarck, and narrowing but continuously developing
towards Minot from 4pm-7pm cdt. This consolidates into a line of
thunderstorms that slides into the James River Valley this
evening. Another area of severe and/or heavy rain develops in
south central ND between 7pm and midnight. This is forecast to
move northeast and expand into the James River Valley with heavy
rainfall late evening into the overnight period. Large hail,
damaging winds, and heavy rainfall continue as the main threats
late this afternoon through tonight. Flash flooding possible in
the southern James River Valley late this evening into the
overnight period. More stable air shifts from west to east tonight
ending the precipitation after midnight.

.LONG TERM...(Monday night through Sunday)
Issued at 206 PM CDT Sun May 22 2016

Broad trough over the western CONUS gradually works eastward towards
the plains through the middle and end of the upcoming week. This
will bring active cyclonic flow to the area, though models are
having quite a bit of trouble with timing out individual short waves
within the system. With that said, will keep chances for
precipitation going given the active pattern. Near to slightly above
average temperatures expected.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1250 AM CDT Mon May 23 2016

Thunderstorms with local MVFR or IFR conditions will continue over
the southern James River Valley until around 10 UTC. Otherwise, a
few showers may linger across central ND overnight, but we expect
VFR conditions to prevail over all but the southern James River
Valley the rest of the night. VFR conditions are expected across
all of western and central ND on Monday.

&&

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

$$

UPDATE...CJS
SHORT TERM...KS
LONG TERM...JJS
AVIATION...CJS



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