Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 241147

Area Forecast Discussion
National Weather Service Grand Forks ND
647 AM CDT Mon Oct 24 2016

Issued at 647 AM CDT Mon Oct 24 2016

Patchy dense fog the main concern right now. These conditions have
expanded across the entire forecast area, however most sites
continue to fluctuate up and down. Given the patchy nature of this
dense fog will continue with the SPS for raising awareness. The
forecast concern then turns to when this fog might dissipate, and
how this timing might affect max temps. Current forecast should be update can address details.


.SHORT TERM...(Today and tonight)
Issued at 345 AM CDT Mon Oct 24 2016

Ideal radiational cooling conditions have led to fog development
across much of the region. ASOS/AWOS observations indicate
visibility fluctuating from 1/4sm to 3/4sm at most sites across
northeast ND and into the northern valley, extending down into
the Fosston/Detroit Lakes area in Minnesota. Mixing is non-
existent until maybe late morning, and given late October solar
any fog should remain until at least mid-morning. With that said,
web cams and phone calls indicate that the dense fog remains very
patchy, and not yet seeing the consistency in lower visibility
that would be required for a dense fog advisory. Issued an SPS to
raise awareness, and will continue to monitor.

Temperatures a bit cooler today, and could be even colder than
forecast if fog does become widespread and lasts longer than
expected. Increasing return flow tonight will keep temperatures
steady after a quick drop this evening.

.LONG TERM...(Tuesday through Sunday)
Issued at 345 AM CDT Mon Oct 24 2016

Tuesday-Wednesday...Rain chances and amounts the main challenge.
Much of Tuesday will be dry, with rain developing by later
Tuesday afternoon. Its a challenging upper level pattern with
multiple waves ejecting from west coast trough. Latest guidance is
picking up on a stronger upper wave to propagate through the
northern plains. This would lead to a stronger low level jet,and
resultant stronger 850mb warm air advection, and higher PoPs
further north (forecast has been trended in this direction). Given
PWATS near an inch (2 standard deviations above climatology),the
quick shot of 0.5 inch to an inch of rain being produced by most
guidance appears reasonable. GEFS probability of exceedance
products indicate west central Minnesota very likely to receive
at least 0.5 inch of rain, with areas west of the valley and north
of a Grand Forks to Bemidji line on the edge (30%-50% chance for
receiving at least 0.5 inch of rain).

Thursday-Sunday...Primarily northwest flow aloft is expected during
this time with operational models indicating the potential for a few
upper waves to impact the area (strongest model signal on Friday).
Precip potential will depend on the exact track of these waves, with
typical model variability leading to low confidence currently.
However, temps generally look to remain near/above average through
the period.


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 647 AM CDT Mon Oct 24 2016

Patchy dense fog and LIFR conditions at all but KFAR and KGFK will
continue into the mid-morning hours. There is a low probability
for KFAR and KGFK to become at least MVFR. All sites should be VFR
by early afternoon.




LONG TERM...TG/Makowski
AVIATION...TG is the U.S. government's official web portal to all federal, state and local government web resources and services.