Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 121434

Area Forecast Discussion
National Weather Service Grand Forks ND
934 AM CDT Thu Oct 12 2017

Issued at 934 AM CDT Thu Oct 12 2017

No reason to change anything in the forecast with this update.
Wind speeds have been increasing and will be gusty through the
day. Warmest high temperatures should still be along the Red River
Valley as winds switch to the west-southwest this afternoon. These
thoughts were covered well with the prior forecast.


.SHORT TERM...(Today and tonight)
Issued at 324 AM CDT Thu Oct 12 2017

Only minimal impacts this period, mostly related to breezy
southerly winds today. Water vapor imagery indicates an upper
level wave across the Pac NW CONUS, which models show propagating
through western North Dakota into southern Canada this evening.
The strongest forcing from this system will remain to the west and
north of this region. With that said, as the upper wave shifts
into Canada, this will force a surface trough/cold front to
propagate through the region this afternoon/evening. Thermal ridge
ahead of this feature along with good mixing potential should lead
to an axis of near 70F afternoon temperatures (cooler on either
side of this axis). Most guidance is slightly cooler than 70F,
but considering the cool model bias the past couple days along
with the set-up feel confident forecasting warmer than guidance.
Mixing layer up to around 925mb, with around 30 knots at this
layer available to mix should lead to winds just below advisory
criteria. Strong 850mb warm air advection on the east side of the
thermal ridge, but a dry airmass will result in no weather until
this forcing interacts with the moister airmass across north
central Minnesota. Northwest winds behind the cold front will be
breezy in the early evening hours across northeast North Dakota,
but with the timing of the cold front mainly during the `dark`
hours, mixing potential is weak. Expect clearing overnight, with
winds becoming weaker by morning. Min temps will likely range from
around 30F across the Devils Lake basin to 35F-40F elsewhere.

.LONG TERM...(Friday through Wednesday)
Issued at 324 AM CDT Thu Oct 12 2017

High pressure ahead of the next system will lead to dry weather on
Friday with seasonable temperatures. Late Friday night an upper
trough approaches the area bringing cooler weather and
precipitation. Rain is likely across the area during the day
Saturday into early Sunday morning. A rain snow mix will be possible
late Saturday night into early Sunday morning as the GFS, NAM, and
ECMWF are all providing cold air aloft with 925 mb temperatures
below freezing. The determining factor for any frozen precipitation
will be if the precipitation stops before the colder air arrives.
Temperatures will be cool this weekend with highs in the 40s and 50s
and lows in the 30s.

Monday through Thursday ridging aloft will lead a return to dry
weather and near normal temperatures. There is potential for some
precipitation on Wednesday but disagreement in model guidance
leads to low confidence at this point.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 630 AM CDT Thu Oct 12 2017

Main aviation hazard today will be breezy southerly winds ahead
of a cold front, and then the wind shift associated with the
passage of the cold front. TVF/BJI most likely to see low VFR cig
around 4000-8000 feet during frontal passage.




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