Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 311950

Area Forecast Discussion
National Weather Service Grand Forks ND
250 PM CDT Tue Mar 31 2020

.SHORT TERM...(This evening through Wednesday night)
Issued at 250 PM CDT Tue Mar 31 2020

Clouds have been increasing west of the Red River this morning and
will continue to increase to the east of the river tonight. Wind
speeds will drop off a little through the evening and then
increase again toward morning. Biggest impact tonight will be when
and how much precipitation may reach the FA. There is already an
area just west of Minot and Bismarck that has been warmer today
with 40 or so dew points. This has created some instability.
Expect some shower and thunderstorm activity to develop in this
area late this afternoon and evening, which will try to hold
together as it moves east into our western FA by late evening and
overnight. There is some 850mb warm advection and somewhat of an
850mb jet, but overall not that impressive. So generally expect
some weakening shower activity for areas along and west of the Red
River Valley tonight. More skeptical on any of this activity
holding together as it moves east of the Valley mainly by
Wednesday morning.

For Wednesday there appears to be a weak boundary pushing into the
FA. There is a re-strengthening 850mb jet and still some weak warm
advection. Most precipitation (although light) appears to remain
along the Canadian border. Wednesday evening should be fairly
quiet for most areas, before the next round of precipitation
begins to enter the southern FA overnight.

.LONG TERM...(Thursday through Tuesday)
Issued at 250 PM CDT Tue Mar 31 2020

The main concern for this period will be the potential for
significant winter impacts Wednesday into Friday. There will also
be impacts with rainfall as it relates to the ongoing flooding
(see hydro section below). Guidance is in good agreement with the
overall pattern and a strong signal for precipitation Wednesday
night into Friday. With that said, there are several details that
remain uncertain due to the unpredictable nature of this pattern
that will ultimately determine overall winter impacts.

Wednesday night-Friday...A strong upper wave will eject from the
central Rockies on Thursday, and then through the region on
Friday. Ahead of this strong upper wave, a strong mid-level
baroclinic zone will be set up somewhere across the northern
plains. Strong mid-level Fgen will lead to potential banded
precipitation before transitioning to more synoptically forced
precipitation as the main upper trough swings through the region.
During the Fgen period of forcing (Thursday), a narrow and
elongated area of heavy precipitation (1+ inch) is possible, with
less amounts elsewhere, so keep in mind that the ensemble and
global model guidance likely have too big of a footprint for QPF.
With that said, the location, amounts, and coverage are still very
uncertain given the large spread in ensemble member from both the
ECMWF and GEFS (in addition, the GEFS vs. ECMWF ensemble means
are greatly different). The details will determine the area
affected as well as residence time of the Fgen at any one given
location and coverage of QPF. P-type is also uncertain with the
baroclinic zone low level thermal profile transitioning from below
freezing along the western edge to well above freezing along the
eastern edge. Impactful snowfall is definitely possible over a
short period of time (across a small area) and snow rates should
be enough to overcome warmer ground temperatures (with snow ratios
around 10:1). Thus, will need to continue to message this
potential via the SPS. Will message at least 4-6 inches of snow
with amounts up to 10 inches possible as 1-1.5" per hour rates for
at least 4-5 hours seems probable (wherever the band sets up).
During the synoptically forced precipitation (Thursday night into
Friday), precipitation will be more widespread, but with lower
rates and over a greater period of time. Anticipate snow for much
of the region during this period of the event as the low level
thermal profile is mostly below freezing. Hard to say if rates
will be enough to overcome warm ground temperatures, but do think
that although coverage will be more widespread, winter type
impacts will be lower. High pressure and cooler temperatures will
move into the region for the weekend. Ensemble guidance in
agreement indicating more active weather and warmer temperatures
returning to begin the work week although predictability is still
very low.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 133 PM CDT Tue Mar 31 2020

The next system moving in very late tonight or Wednesday appears
to be slower now. Therefore, KDVL may be the only site that has a
potential for rain during this TAF period. Wind speeds are fairly
breezy today, but these should drop a little again through the
evening before rising late tonight into Wednesday.


Issued at 133 PM CDT Tue Mar 31 2020

North Dakota Tributaries continue responding to snow melt runoff
working into the system from south to north. The Sheyenne River at
lisbon is now forecast to reach minor flood stage later this week,
with the forecast remaining on track for downstream sites at the
West Fargo Diversion and Harwood, where major flood stage is
expected. The Maple River at Enderlin continues on an upward trend
with the Mapleton site trending downwards. The Wild Rice River at
Abercrombie is currently trending downwards as well; however,
precipitation later this week will likely trigger an upward response
depending upon the exact track of the storm system. Precipitation
type will matter as well, with rain leading to faster river level
rises than snow.

Minnesota tributaries are on the rise as melt water is working into
the system a bit more slowly than in North Dakota. The Marsh River
at Shelly, remains on track to reach minor flood stage Wednesday
morning, with the Sandhill River at Climax reaching minor flood on
Friday and Moderate flood by Saturday morning. Forecasts have been
updated to highlight higher water levels for the Red Lake River at
Crookston, as well as the Two Rivers River in Hallock, both of which
are now forecast to reach moderate flood levels late this week.

For the mainstem Red River, water levels are gradually rising as
runoff pushes northward into the central portions of the Valley late
this week. The Red River at Halstad will reach minor flood stage by
the end of today, with a forecast to reach moderate flood Wednesday
afternoon. Rises in East Grand Forks and Oslo will put those sites
into minor stage on Wednesday, with moderate flood stage expected at
both sites as we head into Thursday (Oslo) and Friday (East Grand
Forks). Oslo is forecast to reach major flood stage this weekend.
Further north, the Drayton and Pembina river sites will see a rise
into minor flood stage late Friday into early Saturday.



River point flood warnings continue across portions of
the region. Refer to the latest flood warnings and statements for
detailed information on specific locations.


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