967 
FXUS63 KFGF 120334
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1034 PM CDT Mon Sep 11 2023

.UPDATE...
Issued at 1034 PM CDT Mon Sep 11 2023

Other than one lingering shower in our southeast most activity
has ended, and most CU has dissipated with clear over a lot of our
area (a few pockets of stratus). Upstream Tds are sill in the 
upper 30s and lower 40s, so there isn't a change in expected 
impacts from the last update. The main adjustments were to reflect
near term trends. 

UPDATE Issued at 640 PM CDT Mon Sep 11 2023

What few showers are left are quickly weakening/falling apart with
peak heating past and sunset approaching, leading to stabilizing
BL conditions. Patchy ground fog remains possible in our far 
south where BL moisture may be just deep enough, while lower Td 
arrive where that main surface ridge is projected to build south 
later tonight/Tuesday morning. 

Clearing skies (outside of areas of stratus) are already occuring
as CU breaks up with decoupling at sunset, but we should see good
radiational conditions in our north. Upstream surface Tds are in 
the upper 30s though where the ridge center is moving out of
Manitoba, lowering confidence in a frost threat (requiring 36F or
less 6ft temps). Still, RAP BL Tds do drop to around 35 after 
10Z, and if those drier Tds mix to the surface as the surface 
inversion steepens, a few spots may drop in the 33-36F range 
(mainly in Towner, Cavalier counties in ND and eastern Marshall, 
northwest Beltrami- bog areas of MN). Due to the marginal/highly 
localized nature of any frost potential, I am still opting not to
go with a frost advisory. I would feel more confident in frost
potential if lower Tds were observed upstream than what I am
seeing.  

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 313 PM CDT Mon Sep 11 2023

-Showers and a few thunderstorms pushing southeastward this
 evening.
-Some stratus/fog possible in some areas overnight
-Clearing in northern counties could drop temps close to frost
 point.

Vorticity lobe on the backside of the upper trough continues to
dig down out of Canada this afternoon, and will progress
southeastwards into MN overnight. Cold front has pushed through
most of the CWA, but scattered showers continue across many of the
counties except the northwest. With 500 J/kg of ML CAPE in
portions of southeastern ND and western MN, some thunder will
continue to be possible for the next few hours. CAMs and larger
scale models are in pretty good agreement on shower and isolated
thunderstorm activity continuing to push southeastward through
this afternoon and early evening. By midnight, think we should see
the showers push fully out of our area. 

Tonight, there will be some subsidence and high pressure coming in
behind the frontal boundary. However, several ensemble members
show some lingering low level moisture, particularly across our
southern and eastern counties. Think our eastern tier will stay
pretty cloudy, as there are high probabilities for low clouds and
even some fog over central ND that could drift westward. There are
even some low probabilities for stratus and fog extending from
southeastern into central ND along the edge of the surface high.
Think at least there will be some cloud cover lingering overnight,
which will have an impact on temperatures.

While the south and east look to remain cloudy with dew points in
the 40s, think there will be some drier air and clearing skies 
across our northern counties. Temps should drop down at portions
of the northern Devils Lake basin and northern RRV, just a
question of how much. NBM probabilities of less than 40 degrees in
that area are between 40 and 70 percent. Confidence in 36 or less
is lower, around 10 to 20 percent, although more recent runs have
been bringing that value up a bit in portions of our far
northwest. Given upstream dew points are still pretty high in the
low 40s to upper 30s, leaned towards the middle of the ensemble
pack with low temps around 37 to 38 in our northwest. Confidence
in anything lower is not high enough to include a frost advisory
at this point. 

Upper ridging between systems will nose into the Plains later
Tuesday into Tuesday night, with the surface high shifting east.
Temps should stay mainly in the 60s during the day on Tuesday even
with some sunshine, but increasing southeasterly winds Tuesday
night will keep our temps in the 40s with some upper 30s in
northwestern MN.  

.LONG TERM...(Wednesday through Monday)
Issued at 313 PM CDT Mon Sep 11 2023

Wednesday and Thursday...Upper ridging comes into the Plains for a 
brief period mid-week before another shortwave comes over the top of 
it into the Prairie provinces and Northern Plains on Thursday. 
Southerly winds will be ramping up on Wednesday as a surface trough 
gets going over the High Plains. This should help boost temps back 
into the 70s by Wednesday afternoon for areas along and west of the 
Red. A cold front will start pushing in late Thursday, but with 
warming ahead of the boundary some spots could still push 80 in the 
southern Red River Valley. Some showers and thunderstorms possible 
as the front pushes through, although moisture is not great and 
coverage looks somewhat scattered. Instability seems fairly limited 
with ensemble averages in the 100-500 J/kg range and even the 
bullish NAM mostly under 1000 J/kg. Severe weather threat is 
minimal. Blended solution gives 30 to 40 percent probs of any 
precip as the front moves through, which seems reasonable. 

Friday through Monday...Upper troughing digs into the Great Lakes 
for the end of the week and into the weekend. This will bring a bit 
of a cool down for the first part of the period, with temps rising 
back to above average values for the first part of next week. Other 
than a few isolated showers possible near Lake of the Woods with the 
cyclonic flow aloft for Fri/Sat, the period seems fairly dry. 

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 640 PM CDT Mon Sep 11 2023

Showers are quickly dissipating across eastern ND and northwest MN
with the loss of peak daytime heating/approaching sunset. There 
is still a lingering stratus layer that may survive beyond sunset
in north central MN towards KBJI that is shown by guidance to 
fill back in overnight with possible IFR by 12Z before eventually 
clearing later Tuesday morning. Other terminals are favored by 
guidance to remain VFR through the remaining TAF period, though 
there is a signal for possible fog and stratus formation in far 
southeast ND and west central MN that could result in 
temporary/brief aviation impacts at KFAR around 12Z (not favored 
but still possible and worth monitoring). 

&&

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

$$

UPDATE...DJR
SHORT TERM...JR
LONG TERM...JR
AVIATION...DJR