Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 211733

Area Forecast Discussion
National Weather Service Grand Forks ND
1233 PM CDT WED SEP 21 2016

Issued at 1233 PM CDT Wed Sep 21 2016

Made a few minor tweaks for current radar trends, but will
continue to have the showers over the north diminish in the next
few hours as frontogenesis weakens. Bumped up highs a few degrees
in the southwestern counties as sunshine as already allowed them
to reach forecasted highs, but think that the rise should level
off soon as clouds move into that area shortly.

UPDATE Issued at 936 AM CDT Wed Sep 21 2016

Adjusted POPs as scattered rain showers continue over the northern
counties, along an area of good 700mb frontogenesis. Models are
pretty consistent on this mid level frontogenesis decreasing as
we head into the afternoon, so will continue the trend of
decreasing POPs after 18Z. Think that the best chances for
something over the southeastern counties will be later tonight
with a shortwave coming out, so kept POPs minimal in that area
until after 00Z. Locations in the southwest CWA should see some
sunshine and get up into the 70s, but the rest of the area should
stay in the 60s.

UPDATE Issued at 658 AM CDT Wed Sep 21 2016

Light rain has moved into the northern half of the area. Tweaked
pops to match radar trends for the morning. Otherwise no other
changes made at this update.


.SHORT TERM...(Today and Friday night)
Issued at 358 AM CDT Wed Sep 21 2016

Split flow will develop across North America. By 12Z Sat northern
stream will be over Canada and southern stream will be over the
states. Upper level trough over the Pacific Northwest will move
into the High Plains of WY/MT, deepen, and take on a negative tilt
by the end of the period. Upper level ridge over western Canada
will also amplify and move into central Canada by 12Z Sat.
Water vapor loop indicated another upper level trough over northern
SASK. The SASK trough will move through southeast Canada and send
drier air into the northeast zones Thu and Thu night.

High pressure over southern SASK and southern ALTA will produce
a dry low level flow out of the northeast through 12Z Fri.
Concurrently some mid level frontogenesis and mid level moisture
will produce light showers/sprinkles over the north/northwest zones
for this morning as rain falls into drier underneath.

Thereafter return flow will bring higher moisture and higher
precipitable waters. Precipitable water rises to over an inch and a
half by Fri/Fri night with the approach of a more significant upper

The surface high pressure system over SASK/ALTA will move into
northern MAN by 12Z Sat. An upper level trough over southern CA will
move into IA and southern MN for Wed night. Low level jet forecast to
remain south and east of the forecast area for Wed night. However
some low level moisture will move north for Wed afternoon/Wed night
into the southeast zones. Will keep low pops for the southeast zones
for this afternoon and Wed night.

.LONG TERM...(Saturday through Tuesday)
Issued at 358 AM CDT Wed Sep 21 2016

The Saturday through Tuesday weather continues to revolve around
placement and strength upper low expected to pinwheel across the
northern plains. Temperatures will generally be seasonal with highs
in the 60s and lows in the 40s. Saturday could be a touch warmer if
dry slot of the upper low allows for more sun with low 70s expected.
As for pcpn placement will depend on track of the upper low and SFC
low...current 00Z runs of the GFS/GEFS and EC are similar in their
solns with the placement of the upper low through Sunday morning.
Then the GFS/GEFS begins to shift the upper low to the east where as
the EC shears it out and lifts most of the energy to the north.
Placement of the wraparound band of rain and duration to be
determined by these possible scenarios. Nonetheless by Saturday
PWats of 1 to 1.5 inches are 3 to 4 times above the standard
deviation for the end of September. Good chances for an inch or more
continue to be across the northern valley and the Devils Lake basin
with a bit less more probable across the southern valley.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1233 PM CDT Wed Sep 21 2016

All sites are VFR as clouds have been mostly mid and high level.
Showers over the northern forecast area have been diminishing and
further development tonight should remain either to the north or
south of the TAF sites. Increasing mid level clouds will bring
some ceilings to around 8000-12000 ft tonight and lower stratus
should stay to the south of KFAR late tonight and tomorrow. Winds
will shift around to the north-northeast and pick up a bit by the
end of the period.


.FGF Watches/Warnings/Advisories...


SHORT TERM...Hopkins
AVIATION...JR is the U.S. government's official web portal to all federal, state and local government web resources and services.