Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 210913

Area Forecast Discussion
National Weather Service Grand Forks ND
413 AM CDT Sat Jul 21 2018

.SHORT TERM...(Today and tonight)
Issued at 321 AM CDT Sat Jul 21 2018

Will maintain air quality alert for smoke per guidance from MN
Pollution Control Agency thru 14z. Smoke analysis indicates a
lessening trend in terms of impacts and focus is over the Red
River valley with HRRR model smoke forecasts indicate the smoke
area to weaken as east winds take over and eventually shift north
as winds turn more south-southeast tonight. Stubborn stratocu on
the NW side of the upper low over Michigan will impact the eastern
fcst area at least thru midday but some sun as well. Better
sunshine coverage in the RRV and eastern ND where temps will reach
near 80.

Mainly clear tonight with some increase in high clouds overnight
into E ND. A few showers or tstorms may reach near DVL region by
12z Sun, but they will be quite weak as they outrun the
instability gradient to our west.

.LONG TERM...(Sunday through Friday)
Issued at 321 AM CDT Sat Jul 21 2018

An upper level low will slowly push east through southern Canada
over the majority of next week driving the area`s weather. First
stop on this weather road trip is Sunday`s cold front moving through
from the west. This feature will provide thunderstorm chances
beginning in central and eastern North Dakota during the afternoon.
Chances then push east into the Red River Valley towards late
afternoon/evening before activity begins to dwindle within
northwestern Minnesota overnight. There remains the chance some
storms could be severe within central and eastern North Dakota with
gusty winds, hail, and a brief tornado or two possible.

Sunday`s set up remains conditional upon how much instability is
acquired ahead of the cold front, and with guidance hinting at
prefrontal cloud debris and marginally steep mid level lapse rates,
optimal instability may be hard to come by. Some medium range
guidance is also suggesting morning convection will continue through
the day. This scenario would also lessen severe potential. Still,
sufficient bulk shear around 40 kts will be present. Shear mostly
comprised of unidirectional westerlies as well as a shear vector
largely perpendicular to the cold front will allow for the
possibility of splitting discrete supercells. Thus the mention of a
couple of tornadoes cannot be negated despite weak low level shear.

Continuing down the road, drying conditions will follow behind the
exiting cold front on Monday with breezy northwesterly winds and
high temperatures around 80 region wide. Dry conditions are short
lived as a tail gating, secondary cold front moves through from the
northwest bringing another round of scattered showers and
thunderstorms. Accompanying these storms will be another possibility
of severe weather given the expected strong shear to be in place,
although details remain unclear regarding the thermodynamic

As the Canadian upper low moves into southern Ontario mid to late
next week, synoptically driven lift and moisture within northwest
flow aloft will remain over the region keeping rain chances in the
forecast through the remainder of the week. Additional days with
breezy northwesterly winds are expected given the proximity of this
low and cold air advection over the region. Speaking of cold air,
cooler than normal temperatures are expected Wednesday through
Friday with highs remaining in the 70s, although the likelihood of
overnight cloud cover will moderate lows to be within the 50s.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1146 PM CDT Fri Jul 20 2018

MVFR ceilings have been going in and out of KBJI, but the rest of
the TAF sites are VFR. Some lowered vis of 3-5SM have been showing
up at some other airports across the region. Hard to say if they
are BR or smoke. Think that as we decouple the areas of lower vis
will become more widespread as smoke particles or possible mist
settle. Guidance is a bit more consistent with lower vis so
included 3-5SM at all TAF sites for a period during the early
morning hours. Have smoke mention in the northern three TAF sites
and BR at KBJI and KFAR based on location of Canadian fires. Think
there should be enough mixing and northeast winds pushing smoke
out of the area for TAF sites to return to VFR by mid morning.




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