Area Forecast Discussion
Issued by NWS Grand Forks, ND

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516
FXUS63 KFGF 240234
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
934 PM CDT Sat Sep 23 2017

.UPDATE...
Issued at 931 PM CDT Sat Sep 23 2017

Very weak instability with MLCAPE mainly southeast of CWA, as
supported by lightning being confined to eastern SD and w cntrl MN
just south of our FA. Will lower threat for overnight isold TS
Grand County through southeastern Otter Tail county. Fine tuned
POP grids but overall evolving as expected.

UPDATE Issued at 640 PM CDT Sat Sep 23 2017

Rain showers have now entered srn RRV and will continue to lift
north throughout the night. Made some changes to POPs with latest
ECAM guidance which does seem a bit slow...so pulled the higher
POPs about a county further north each hour. No changes beyond
06Z.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 300 PM CDT Sat Sep 23 2017

Short wave energy associated with strengthening upper jet will
expand rain shield to our south remainder of the afternoon into
tonight propagating northeast into the fa overnight into Sunday.
As it does low level boundary retrogrades westward with quite a
bit of overrunning rain into the fa. Convective parameters weak
however airmass moist with precipitable h2o values from 1.25-1.75
inches should aid in a respectable rain event for parts of the
the region mainly close to mentioned surface boundary. Based on
clouds and expected dewpoints lows will range from the mid 40s to
mid 50s.

A soggy Sunday for most areas with most significant rain from
southeast north dakota into nw Minnesota. Little recovery in
temperatures expected.

.LONG TERM...(Sunday night through Saturday)
Issued at 300 PM CDT Sat Sep 23 2017

Rain will finally shift east Sunday night as jet axis and
associated boundary pushes back east. Rain should be through all
but the far east by morning. Clouds likely to linger and with cool
airmass in place temperatures will continue in the 50s.

Main chunk of energy with western trough lifts ne Monday. Just
how far east low level boundary gets will determine rain potential
later Monday into Monday night. Cool temperatures to continue.

Guidance continues to suggest the upper level trough currently over
the Great Basin is expected to split with its northern stream moving
through the Dakotas on Tuesday. DCVA over the Upper Midwest will
allow a surface low to develop along a southwest-northeast boundary
within Iowa, Wisconsin, and into the UP of Michigan. Guidance
differs with moisture transport around the northwestern side of this
surface low keeping confidence of rainfall amounts and placement
somewhat on the lower side. At this time, eastern and southeastern
counties within the CWA hold the best chance of seeing rainfall
Tuesday. By Wednesday, AVA aloft will dry things out. This is short
lived however as another upper level low moves towards the region,
this time from Manitoba/Ontario into the Upper Midwest/Western Great
Lakes. Run to run guidance has varied greatly with this system, but
there is a chance of rain attached to a cold front associated with
this system around the Thursday timeframe. Surface high pressure is
then expected to nudge into the area Friday into Saturday drying
things out again.

Temperatures are expected to remain on the cooler side with no
appreciable return flow expected throughout the period. Also, frost
potential will need to be monitored Friday and Saturday mornings
behind the late week cold front. Late period differences keep
confidence low at the moment, however the combination of a cool
airmass aloft and building high pressure may aid in this
potential.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 640 PM CDT Sat Sep 23 2017

Mainly MVFR across eastern ND and the RRV with IFR further north.
Areas of MVFR will likely see cigs drop into IFR range through the
night...with all sites predominantly IFR cigs by noon Sunday. Rain
showers will spread south to north across the region and continue
through much of the TAF period.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

$$

UPDATE...Speicher
SHORT TERM...Voelker
LONG TERM...CJ/BP/Voelker
AVIATION...Speicher



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