Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 161157

Area Forecast Discussion
National Weather Service Grand Forks ND
657 AM CDT Wed Aug 16 2017

Issued at 657 AM CDT Wed Aug 16 2017

Radar continues to show the rainfall across the Devils Lake region
winding down. Showers are pretty spotty elsewhere, and really
don`t expect that to change until later this morning into the
afternoon, when they get more organized across the far southern
Red River Valley into west central Minnesota. There has been a
little fog, mainly across the Devils Lake region into the northern
Red River Valley. Added this to the forecast just for the next few
hours. 06Z NAM and GFS continue to show west central Minnesota
picking up the most rain today/tonight. Both have some higher
bullseyes of rainfall too, but confidence in the 06Z runs not all
that high. Will have to see what the 12Z model runs come up with.


.SHORT TERM...(Today and tonight)
Issued at 337 AM CDT Wed Aug 16 2017

Rainfall amounts and where and when it will fall remain the main
forecast challenge. To start off, rainfall so far early this
morning has mainly been restricted to the Devils Lake region. The
KMVX radar is estimating about 0.50 to 1 inch for a good portion
of that region, with even some localized higher amounts. At this
time yesterday, the models were showing that falling across the
southern Red River Valley into west central MN. Meanwhile, there
has really been hardly anything across the southern valley into
west central MN. The deep convection down over Nebraska has been
producing the really heavy rains. The SPC mesoanalysis page shows
two segments to the low level jet, one feeding into the showers
over the northern valley and the other into the convection in
Nebraska. Through sunrise into the morning hours today, expect a
weakening trend to the showers over the northern valley, but
sporadic showers also occurring most everywhere.

Going forward to this afternoon and tonight, there seems to be a
general slow down to the system. The 700mb low deepens over
eastern SD by 18z Wed, then tracks slowly east-northeast into east
central MN through 12z Thu. The short term high resolution models
show stronger convection breaking out around Sioux Falls SD by
early afternoon then tracking it east-northeast into MN. This
should begin to spread steadier showers with some embedded thunder
mainly into the far southern Red River Valley and west central
MN. Due to the slow movement of the 700mb low, there looks to be a
prolonged period of this steadier pcpn for mainly west central
MN. Therefore this looks to be a longer duration event that it did
at this time yesterday. Pcpn amounts for west central MN from
this afternoon into tonight look to range from 1.00 to 1.50
inches. Much less rain is expected for other areas. So looking at
totals from what is occurring now through what is expected
today/tonight, the least amounts may be from Valley City ND up
toward Hallock MN. Meanwhile, the Devils Lake region received the
decent amounts last evening and west central MN up toward Bemidji
should get the most today/tonight. Since both these areas did not
get the higher end amounts from the past weekend system, it should
not result in any ponding/flooding issues. It will also fall over
a prolonged period, not particularly heavy at any one time. It
looks like clearing will spread into the western FA tonight, and
with light winds and the recent rainfall, there may be some fog.

.LONG TERM...(Thursday through Tuesday)
Issued at 337 AM CDT Wed Aug 16 2017

The above mentioned system should push off to the east on Thu,
with clearing moving in behind it. This will be short lived
however, as the next system will begin to spread in some lower end
pcpn chances for Thu night into Fri. Instability is minimal Thu
night, but some tries to creep into mainly the eastern FA on Fri,
which should bring some thunder back to the area.

For Sat through Tue...The weekend still looks warmer and dry,
owing to building high pressure both at the surface and aloft. A
dry sfc boundary is progged to swing through the forecast area Sat
night or early Sun but the next threat for convection should hold
off until the approach of a short wave on Mon. The GFS and ECMWF
closely agree on the timing of these features with the heart of
the activity likely to favor the southern part of the region on
Mon. High pressure brings tranquil conditions for Tue.

Temps will rise to the low and mid 80s for the weekend before easing
back just a bit for the beginning of the new week.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 657 AM CDT Wed Aug 16 2017

Have been able to eliminate the rainfall at KDVL, but the other
TAF sites will still be dealing with showers throughout the day.
KFAR and KBJI will probably be dealing with rainfall for the
longest. Not entirely certain that KFAR and KBJI will be dealing
with heavier rain, as it could stay just south of both sites.
Otherwise, models continue to keep clouds in the MVFR range for
the most part. Clouds will decrease first at KDVL, so with light
winds and the recent rainfall, there may be some fog by Thursday




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