Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 290751

Area Forecast Discussion
National Weather Service Grand Forks ND
251 AM CDT Mon May 29 2017

.SHORT TERM...(Today and tonight)
Issued at 223 AM CDT Mon May 29 2017

Showers moving in from Canada will continue to be the issue for
the period.

The upper low continues to rotate along the Ontario/MN border,
with various shortwaves coming down into the CWA from Canada. One
such shortwave is coming into our northern counties and producing
scattered showers across the central 2/3rds of the CWA. Will
continue to keep scattered showers mention for the early morning
hours. More shower development will be possible later today as
with the cold upper low in the area there will be steep lapse
rates and showers developing across most of the area. Another
fairly vigorous shortwave will dig down tonight and help more
showers develop. With minor waves it will be difficult to pinpoint
exact placement of showers except for a general trend more towards
the east as the upper low slowly pulls further away. Will continue
to keep fairly broad areas of 20-50 POPs. CAPE values will be
minimal so will keep precip as showers for now.

The northwest winds will continue to be fairly breezy, although
the speeds will start slowly coming down as the pressure gradient
relaxes. Some higher gusts will continue to be possible near the
showers. Clouds and precip along with cold air advection will keep
temps from rising too much this afternoon, so kept highs in the
50s with some low 60s in the southern counties. The clouds and
northwest winds will help lows tonight remain in the 40s.

.LONG TERM...(Tuesday through Sunday)
Issued at 223 AM CDT Mon May 29 2017

Tuesday and Wednesday...Another weak shortwave coming down the
backside of the upper low will continue to bring shower chances,
mostly east of the Red River by afternoon as the system finally
begins to pull away. Skies should begin to clear Tuesday night
although west winds will keep us from completely decoupling. Have
lows mostly in the 40s although some slightly lower readings in
the south near the center of the surface high are not out of the
question. Northwest flow aloft setting in for Wednesday will help
temps rise back up into the 70s.

The Thursday through Sunday period will start off warm and dry as a
500 mb temporarily builds into the northern plains, but end up on a
stormier side.  A pattern change does seem to be occurring but how
long it lasts is highly different among the latest ECMWF and GFS
runs.  A 500 mb trough does move east and sits off shore Washington
state and British Columbia.  Once impulse from this will move east
and across North Dakota Friday night and Saturday with showers and a
few t-storms a good bet, though highest rainfall amounts tend to
favor western and central North Dakota in a region where rainfall is
needed badly.  After this system into Sunday and beyond differences
mount in that the 00z ECMWF build an upper ridge in place vs the 00z
GFS re-develops an upper low just east of us and brings in cooler
air.  Blended model solns work best in these cases and see no reason
to deviate from their output.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 629 PM CDT Sun May 28 2017

VFR with gusty NW winds continuing through late evening. Model
guidance is bringing IFR/MVFR cigs early morning however will not
go nearly as aggressive and keep cigs generally 2K to 3K. Gusty
NW winds return tomorrow aftn however isold -shra not expected to
mix down nearly as strong as winds as experienced today. Main
impacts will be the MVFR cigs in the 10Z to 17Z timeframe.




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