Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 202356
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
656 PM CDT Sun Oct 20 2019

.UPDATE...
Issued at 654 PM CDT Sun Oct 20 2019

Tweaked winds and dewpoints for the overnight otherwise little
change at this update.

&&

.SHORT TERM...(This evening through Monday)
Issued at 348 PM CDT Sun Oct 20 2019

Main impacts through Monday night will be widespread rain and windy
weather. Early afternoon satellite imagery shows the approaching CO
low poised over the High Plains with a strong jet streak digging in
from the Pacific NW, prompting strengthening of the system as it
propagates east across the Central Plains toward the Great Lakes.
Expect modest warm air advection wrapping around the low to yield
widespread rain late tonight through Monday morning across the
region. Deterministic models show strong mid level Fgen forcing
developing across parts of the James River Valley and Devils Lake
basin tonight, allowing for periods of moderate to heavy rain to
develop. The latest model runs back off a bit in terms of the
duration of this mesoscale forcing, hinting at slightly lesser rain
amounts than previously expected, but ensemble guidance continues to
show potential for some locations to see up to 2 inches of rain in
this region (heaviest amounts tonight). Further east over MN lakes
country, increased rainfall amounts again (now in the 1-2 inch
range) as the latest model runs reintroduce strong Fgen forcing just
northwest of the stacked system tomorrow afternoon and evening.
Outside of these areas, most locations in northeast ND, far
northwest MN, and the immediate RRV can look to still see a half
inch to inch of storm total rainfall. Rain will taper off slowly
west to east from Monday afternoon through Monday night, with rain
chances lingering in northwest MN heading into Tuesday.

Of additional concern is strong north winds ramping up Monday
morning as diurnal boundary layer coupling mixes down low level jet
winds and a strong pressure gradient develops. Expect sustained
winds of 25-35 mph with gusts up to 45 mph across much of the region
on Monday afternoon and night. This will likely reach wind advisory
criteria, but uncertainty lingers regarding the areal and temporal
extent of the strongest winds, which could linger well into Tuesday.

.LONG TERM...(Tuesday through Sunday)
Issued at 348 PM CDT Sun Oct 20 2019

By Tuesday into Tuesday night, the big storm system should be
lifting slowly north-northeast into southern Ontario. There may
still be a few lingering rain or snow bands over northwest
Minnesota, but the rest of the area should be dry. Then by very late
Tuesday night into Wednesday, the models show another short wave
rotating around the large stacked low over Ontario. This piece of
energy mainly tracks across western North Dakota into eastern South
Dakota, but some light precipitation associated with it may glance
southeast North Dakota into the far southern Red River Valley. Since
it appears to be more of a glancing shot, any precipitation for this
FA would be minimal.

A 500mb trough builds in behind the departing low for Thursday into
Thursday night. Some colder air in the 925-700mb layer builds in,
which may be enough to produce some lake effect snow downstream of
some of the larger lakes across northwest Minnesota. Later shifts
can monitor that potential, as some of the operational models are
showing precipitation downstream of these larger lakes.

Ridging does appear to build back in for the Friday and Saturday
time frame. High temperatures look to rebound back into the middle
40s to lower 50s. Finally, by late Saturday into Sunday, a 500mb low
begins to dig down the California coast. This turns the flow over
the Northern Plains back to the southwest. Although this is quite a
ways out, the models are showing a boundary sagging through the FA,
and the potential for some light precipitation along it. In
addition, this knocks the temperatures back to the cooler side
again.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 654 PM CDT Sun Oct 20 2019

Mostly VFR conditions were across the forecast area. Expect MVFR/IFR
conditions as cigs and visibilities lower in the western and
southern zones as rain moves in from the south and west overnight.
MVFR/IFR conditions will spread east and north over northwest MN
during the day Mon.

&&

.HYDROLOGY...
Issued at 112 PM CDT Sun Oct 20 2019

The system expected to bring the next widespread rainfall to eastern
North Dakota and the northwest quarter of Minnesota is approaching
from the southwest today. This system is expected to bring
widespread 0.50 to 1.00 inch rainfall amounts to the area, with the
potential to drop up to 1.50 in some smaller areas. At this point,
it appears the favored region for receiving totals in the 1.00 to
1.50 inch range will be over the James and Sheyenne river basins of
eastern North Dakota.

The river forecasts used these above mentioned precipitation
amounts, which brought some changes to the river forecasts today.
The biggest change was at Valley City, where the forecast is mainly
based on releases from Baldhill Dam. Releases from the dam will be
increased, which will bring the forecast for the Sheyenne River at
Valley City above major flood stage. It will take longer for the
releases from Baldhill to affect other sites further downstream.
Other than for the Sheyenne River at Valley City, new river flood
warnings were issued for the Snake River at Alvarado, the Red Lake
River at Crookston, the Maple River at Enderlin, and the Goose River
at Hillsboro.

Elsewhere along the mainstem Red River and its other tributaries,
the main impact will be prolonged high river levels and perhaps
additional crests (mainly in minor to moderate flooding).

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

$$

UPDATE...JH
SHORT TERM...BP
LONG TERM...Godon
AVIATION...JH
HYDROLOGY...Godon


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