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Displaying AFOS PIL: AFDFGF Received: 2021-06-16 18:22 UTC


884 
FXUS63 KFGF 161822
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
122 PM CDT Wed Jun 16 2021

.UPDATE...
Issued at 105 PM CDT Wed Jun 16 2021

A few showers and weak thunderstorms have developed in Barnes and Cass
counties, which should move east over the next few hours near the
Fargo-Moorhead metro area. This is a little unexpected as there
is supposed less than -300 J/kg of CIN in place due to warm H7
temps. Additionally muted insolation from smoke is evident further
limiting instability. Nevertheless they are finding a way to 
sustain and continue within the thermal ridge, leading to the 
belief they are driven by WAA processes. This convection is being 
fed by weak to moderate instability (MLCAPE values 1-2 kJ/kg), and
strongly sheared environment as noted on KMVX VAD. Because of 
this environment, the convection does bare watching. Luckily 
satellite and radar trends have showed a plateau in 
strengthening, so perhaps the capping/lack of better BL moisture 
is keeping it at bay.

Otherwise, gusty southerly winds out there ahead of the front with
a muted heating trend as expected.

UPDATE Issued at 1000 AM CDT Wed Jun 16 2021

Morning light is revealing a plume of elevated smoke moving east
across the Dakotas from fires in the West. This is expected to
effect the temperature forecast by decreasing them. Using current
trajectories of the plume and HRRR smoke model, thinking this will
have most effect on daytime temps within the RRV into NW and WC
MN as it moves over these locations during peak heating (Noon-7pm
CDT). Upper 90s in the southern Valley do not appear likely 
anymore, with most locations staying in the 80s to low 90s.

This lack of insolation may serve to further inhibit the potential
for thunderstorm initiation along the front this afternoon. 
However there is still the expectation of more robust convection 
to develop near focused WAA ahead of a revamping LLJ this evening 
within central MN, some of which may be strong to severe. It 
remains unclear if this activity will blossom in our eastern 
counties, but it appears the chance for initiation within the 
Valley just went down.

There remains some WAA driven sprinkles/thundershowers in eastern
ND through the morning as driven by last night's WAA/LLJ
convection in western ND. The expectation is for this activity to
wane around midday within the RRV, but may continue to move east 
into far NW MN. This activity is currently not expected to be
strong to severe.

Otherwise, gusty south-southeast winds 20-35 mph are developing 
as expected ahead of the front.

UPDATE Issued at 628 AM CDT Wed Jun 16 2021

A single cell has developed southwest of Minot and is moving east.
Doubtful it will hold together to make our western zones, but
could see some increased cloud cover going into the Devils Lake
area. At this point do not think it would impact temperatures but
that will depend on cirrus blowoff. For an increase in sky for the
morning hours at will bring TS into areas just west of Devils
Lake.

&&

.SHORT TERM...(Today through Thursday)
Issued at 200 AM CDT Wed Jun 16 2021

The forecast challenge for the short term period will be potential
for convection associated with a cold front moving across the
region today.

This morning starts with a high amplitude upper ridge in place,
however an upper wave moving out of the Pacific NW into Alberta
will help flatten the ridge out as it shifts east of the CWA by
00Z. At the surface, a cold front moves into the western zones
during the mid afternoon. NBM dewpoints pool around 65 deg
dewpoints along the frontal boundary during peak heating, however
that seems a tad high compared to what is upstream...and have
lowered them to the 58 to 62 range across the CWA. This will be
the axis for modest afternoon CAPE, HOWEVER, a solid H700 thermal
ridge axis moves over the CWA by late afternoon. With H700 temps 
around 13 to 15 C, believe the CAP will be hard to break given the
best lift will be across Manitoba as the aforementioned wave 
moves across the lower western provinces. Best PVA will be across 
the Manitoba lakes, with very weak PVA moving across the southern 
valley.

Given the CAPE values, if the thermal cap did break a few severe
storms are possible in the higher dewpoints across west central
MN, but confidence for this scenario is low given the strength of
the cap. A more likely scenario is to get weaker storms or showers
in the far east during the overnight period as cooler H700
temperatures move into northeastern MN. The best chance for
convection is more than likely going to be vicinity of Lake of the
Woods tonight.

Another concern has been strength of southerly winds this
afternoon. Soundings for the Fargo area have max winds in the
adiabatic layer only around 20 to 25 kts, so the slightly lower 
winds on the latest NBM run make sense and have lowered winds
accordingly.

Dry and much cooler temperatures arrive for Thursday, with todays
highs in the 90s falling into the 80s tomorrow.

.LONG TERM...(Thursday night through Tuesday)
Issued at 200 AM CDT Wed Jun 16 2021

The main impacts in the long term look to be the return to below 
normal temperatures and a better chance for widespread rainfall.

The 500mb low that crosses Canada and flattens the ridge in the 
short term begins to drop southeast over the Great Lakes Thursday 
night into Friday. Cyclonic flow, cooler 500mb temperatures, 850mb 
cold advection, and a secondary surface cold front all mark this 
time frame. The results will be a markedly cooler day Friday with 
gusty northwest winds and scattered showers (mainly across northwest 
Minnesota). Behind this, the 500mb flow becomes more zonal from 
Friday night into Saturday.

By Saturday night into Sunday night the next 500mb wave tracks 
through the FA. At this point, this looks like the best chance for 
widespread rainfall across the FA. However, overall precipitation 
amounts at this point do not look to be all that great. The 
Canadian, GEFS, and ECMWF ensembles all show high probabilities for 
greater than 0.10 inches, but low probabilities for greater than 
0.50 inches. So this period should be cool, breezy, and wet. There 
is more forecast uncertainty by Monday into Tuesday in regard to 
lingering precipitation chances. However, there is a little better 
certainty in the continued below normal temperature regime with 
breezy winds. In addition, surface dewpoints look to be abnormally 
dry, with the NBM showing them to be in the 30s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 105 PM CDT Wed Jun 16 2021

VFR conditions are expected, with the exception of KFAR where a
cluster of showers and weak storms should move near the TAF site
between 20-22 UTC. Gusty south-southeast winds will be present
ahead of a cold front this afternoon. There will be a lull in
winds as the front passes, followed by increased northwest winds
after the front passes. There is a slight chance of additional
thunderstorms within northwest and west-central MN later this
afternoon, which may impact KBJI. Confidence wasn't high enough to
include within the 18 UTC TAF suite, but will amend if needed.

&&

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

UPDATE...CJ
SHORT TERM...Speicher
LONG TERM...Godon
AVIATION...CJ