Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 221734

Area Forecast Discussion
National Weather Service Grand Forks ND
1234 PM CDT Thu Sep 22 2016

Issued at 1228 PM CDT Thu Sep 22 2016

Canadian surface high and northeast flow is keeping northeastern
half of CWA clear with some 4K to 5K cigs entering southeastern
ND. Overall grids look in good shape for today and tomorrow, with
main threat for precip being tomorrow night however some isolated
showers in the far south and west certainly are possible later
this afternoon.

UPDATE Issued at 623 AM CDT Thu Sep 22 2016

No update needed at this time. Forecast on track with Canadian
SFC high pressure airmass advecting across the FA on northeast


.SHORT TERM...(Today and tonight)
Issued at 352 AM CDT Thu Sep 22 2016

Models in fair agreement with the forecast especially in the
first 24 to 36 hours. 500mb ridging will strengthen today across
the northern plains in response to strong upper low over the
western US. At the surface northeast winds from a SFC high
pressure moving across Manitoba today will be advecting drier air
across the FA. This will bring plenty of sun with temps in the mid
to upper 60s with some high clouds in the west and south. A rather
tight pressure gradient will help keep winds mixing overnight with
some clouds in the south causing temps to range from upper 40s
north to low 50s south by Friday morning.

.LONG TERM...(Friday through Wednesday)
Issued at 352 AM CDT Thu Sep 22 2016

Models continue to come into better agreement with the timing and
evolution of the upper low and subsequent precipitation potential.
Have delayed PoPs some for Friday as drier low easterly flow will
Hinder eastward and northward progression of rain. Once 850mb flow
becomes more southerly late Friday into Saturday morning PWats
will increase to 1.5 to 1.75 inches, which is 3 to 4 standard
deviations above normal for the end of Sept, precip is more likely
as mid level q-vector divergence provides the needed lift. First
round of precip Friday night associated with lead impulse will
bring the higher chances to the Devils Lake basin. The next round
will bring a band of likely PoPs oriented south southeast to the
north northwest advancing east during the day Saturday. Timing of
the dry slot and how far east it pushes will continue to be
evaluated as there remains potential that eastern zones may see a
more prolonged period of rain if the dry slot lifts more north and
allows the rain band to stall Saturday night. Current ensemble
means from the 00Z model runs give the area between a half to an
inch of rainfall for the FA. This is a widespread average with
some locally higher amounts expected and some locally lesser
amounts expected. The higher amounts from model QPFs continue to
be across the Devils Lake basin across the northern valley and
into the far northeastern zones of the FA.

Long wave trough over the Intermountain West weakens through the
period. Long wave ridge over central Canada shifts east and flattens
through the period. The ECMWF was trending faster and farther north
while the GFS was also trending slower and farther south. The two
models diverge after 84 hours with the GFS slower and the ECMWF
faster. Will blend the two models.

Little change to high temperatures for Sun, Mon and Wed. High
temps were decreased a degree or two for Tue.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1228 PM CDT Thu Sep 22 2016

VFR cigs around 4K to 5K feet will advect from southeastern ND
northward during the TAF period, reaching FAR mid morning
tomorrow. Precip should generally be after the current TAF period
although an isolated shower VCNTY DVL certainly possible this
afternoon. Northeast winds will keep northern valley and northwest
MN clear for most of aftn with mid level cigs moving in by




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