National Weather Service Raw Text Product

Displaying AFOS PIL: AFDFGF Received: 2021-09-19 19:45 UTC

FXUS63 KFGF 191945

Area Forecast Discussion
National Weather Service Grand Forks ND
245 PM CDT Sun Sep 19 2021

.SHORT TERM...(This evening through Monday night)
Issued at 244 PM CDT Sun Sep 19 2021

The expected convection tonight into Monday is the main forecast
challenge. As of mid afternoon, the surface front had reached a
Cavalier to near Jamestown line. Dewpoints really tail off quickly
behind the front, with Rolla already at a dewpoint of 41.
Meanwhile, ahead of the front, temperatures were in the mid 70s to
mid 80s (dependent on cloud cover) with dewpoints in the lower
60s. The SPC mesoanalysis page continues to show 700mb
temperatures in the +10 to +12C range, with abundant SBCIN and 
MLCIN. It continues to look like any shower/thunder development
will hold off until somewhere in the 8 to 10 pm time frame, as the
low level jet intensifies once again. Many of the high resolution
models show development during this time frame somewhere between
Fargo-Moorhead, Wahpeton-Breckenridge, and the Bemidji-Park Rapids

By late evening and overnight, the approach of the main 700mb 
shortwave will aid in additional, more widespread shower and 
thunder activity. The 12z HREF 4hr max 2-5km updraft helicity 
greater than 75 probabilities begin to pick up about the 8 to 10 
pm time frame too, and peak in the hours just after midnight. With
the SPC 3hr calibrated severe storm probability chart also 
showing steady values within the same sector during the mid to 
late evening and early overnight hours, a few strong to severe 
storms remain possible. The HREF and NBM continue to highlight the
Upper and Lower Red Lakes/Baudette/Bemidji areas with the highest
probabilities for an inch or more of rain. This rain will end 
from west to east on Monday, with another gusty wind day (this 
time from the northwest) expected.

.LONG TERM...(Tuesday through Sunday)
Issued at 244 PM CDT Sun Sep 19 2021

A mostly quiet long term period is expected. There are some 
indications for potential frost in some spots on Wednesday morning, 
especially in northwest Minnesota where spots are typically most 
cool overnight.

Following the trough exiting the area overnight tonight, ridging 
upstream will begin to intensify once again. Northwesterly flow for 
most of the period will keep widespread precipitation chances to a 
minimum. With the noticeably cooler airmass behind tonights cold 
front, more seasonable temperatures will be expected for the early 
part of the week. There is the potential for some frost on Wednesday 
morning, especially in northwest Minnesota where winds are typically 
the lightest and overnight temperatures fall the furthest. At this 
time, first freeze probabilities seem low, with NBM probabilities 
for <32F at less than 1% for most of the area and <5% along our 
eastern CWA border (Beltrami/Lake of the Woods county area).

There are some hints at a shortwave passing through late work week 
(around Friday), although spread is wide in amplitude of the wave 
and timing of the wave, so confidence isn't too terribly high. 
Moreover, appreciable instability probabilities are low, so 
thunderstorm risk isn't expected to be terribly high. At this time, 
the greatest chances for rain will be further north and east. 
Attached to this shortwave is another cold front, reinforcing fall 
temperatures by late week and making for a very breezy Friday.

Spread begins to widen out rapidly towards the end of 
the period, so there isn't a whole lot of confidence in how the 
weekend will shape out temperature-wise.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1255 PM CDT Sun Sep 19 2021

The main aviation impacts will be wind gusts through the afternoon
today and then shower/storm activity starting up this evening into
the overnight hours. Wind speeds should decrease by mid to late 
afternoon in most areas, as a front moves into the FA. This front
should reach a Hallock to Grand Forks to Valley City line by late
afternoon, where it may stall for a while...until it gets moving
again very late tonight. So eventually, the entire FA will see the
wind switch to the northwest. As far as thunder chances, most
guidance points to mid evening for a start time, with pretty
steady rain developing close to midnight and continuing through
most of the overnight. Getting into mid Monday morning, the rain
should end from west to east, but there is also a signal for
potential MVFR conditions from sunrise through mid morning or so
(along with increasing northwest winds again). Since the TAFs were
already so long, did not mention the mid morning wind increase
with this set of TAFs, but it looks like it will be there again.



LONG TERM...Perroux