Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 231632

Area Forecast Discussion
National Weather Service Bismarck ND
1132 AM CDT Thu Mar 23 2017

Issued at 1127 AM CDT Thu Mar 23 2017

Little overall change. Did lower highs across the southwest into
the 40s as cloud cover and additional precipitation will prevent
temperatures from reaching the 50s. Otherwise, grids were blended
to observed trends through 16 UTC.

UPDATE Issued at 750 AM CDT Thu Mar 23 2017

Quick update to increase PoPs based on radar trends through 1245
UTC, blended thereafter to the 10-11 UTC HRRR/RAP. Did expand the
mention of freezing rain to most of the James River Valley this
morning where road temperatures are around 31-32F with rain
inbound. Issued an SPS to highlight a potential for a brief period
of freezing rain until road temperatures can warm sufficiently
after sunrise.

UPDATE Issued at 647 AM CDT Thu Mar 23 2017

No changes with forecast or previous thoughts with the forecast.
Main issue in the next couple hours remains the brief window of
opportunity for possible freezing rain across central portions of
ND. Temp at KBIS is 33 and road temps have been at or slightly
below freezing, with area of light precip moving into the area.
KHEI only reported .02 inches of precip and incoming sounding data
here at the office showed some dry air between 850 and 700 mb to
be overcome. Mandan airport just reported unknown precip type
which matches well with timing of radar.


.SHORT TERM...(Today and tonight)

Issued at 425 AM CDT Thu Mar 23 2017

Forecast highlights in the short term period will be increasing
chances for rain this morning spreading east and north, with a
brief window for freezing rain central early.

Currently, upper level ridge axis east of the Dakotas with
southwesterly flow aloft increasing into the region. Lead embedded
S/WV impulse ejecting out of a potent upper level trough over the
Desert Southwest lifting northeast across Wyoming towards the
Northern Plains early this morning. Favorable upper level jet
dynamics as well with both left exit and right entrance region
upper level divergence in play. Resultant precipitation ahead of
the mid level wave just entering southwest ND as of this writing.
Cluster of lightning strikes just to our south over Perkins
County SD, though high res models suggest instability to support
thunderstorms remaining to our south. We opted to keep thunder
out of the forecast (to avoid over-forecasting convection) though
there is a possibility for an isolated storm or two this morning
as models do show some weak MUCAPE over my far south. Future
updates may be needed depending on the coverage of any potential
thunder activity.

Main challenge this morning is whether or not we will see
freezing precipitation. Surface temperatures and road surface
temperatures do suggest a possibility. Latest HRRR/RAP/NAM Bufkit
soundings all agree on the potential for at least a brief window
(1-2 hours) for freezing rain over portions of south central ND
before both air and road temps increase, with a few hundreths of
ice accumulation forecast by high res guidance between now and 8AM
CDT, which is roughly the same time frame the METRo Roadcast
model also indicates the potential for ice. We decided to add
this back into the HWO and also will highlight in the weather
story and other products.

Chance for rain continues in the afternoon, though forcing will
be on the decrease with the main push already moving east-
northeast by 18-20Z. Lingering clouds over my central and east
tonight, with mostly clear conditions west.

.LONG TERM...(Friday through Wednesday)

Issued at 425 AM CDT Thu Mar 23 2017

Quiet and mild Fri & Sat as split flow aloft keeps the storm
tracks north and south of North Dakota. Quasi-active flow returns
late this weekend and into next week, though no impactful weather
is foreseen and temperatures will remain seasonal.


.AVIATION...(For the 12Z TAFS through 12Z Friday)
Issued at 1127  AM CDT Thu Mar 23 2017

Rain continues across southwest and south central North Dakota
late this morning and will slowly diminish late this afternoon and
into the evening. Otherwise, mainly VFR conditions expected today
with the possibility of fog developing across much of the area


Issued at 309 PM CDT Wed Mar 22 2017

In response to increased releases from Alameda Reservoir, Lake
Darling will increase its releases to 1000 CFS by Thursday, with
the potential for further increases next week. This will cause the
Souris River downstream of Lake Darling near Foxholm to rise but
remain just below flood stage. As this pulse of water travels
further downstream where greater ice cover remains on the Souris
River, ice break up will have to be closely monitored.
Furthermore, snowmelt will be on the increase with a sustained
period of above normal temperatures late this week and through
next week. While soil moisture was high across the Souris Basin
going into the winter, early snow insulated the ground, preventing
much frost from forming. Thus, some uncertainty remains as to how
much melt from the snowpack will infiltrate into the ground
versus runoff and reach the river, streams and coulees.




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