Area Forecast Discussion
Issued by NWS Grand Forks, ND

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KFGF 220451

Area Forecast Discussion
National Weather Service Grand Forks ND
1151 PM CDT Thu Sep 21 2017

Issued at 1147 PM CDT Thu Sep 21 2017

Elevated instability increasing at the 850 mb level as expected at
05z and we have seen an increase in scattered convection in
central MN and in the Bemidji area. Also have seen isolated
convection form near the actual frontal boundary NW of Grand
Forks. HRRR model has seemed to be pretty good tonight and it
shows that area from Sisseton to Alexandria to St Cloud developing
more the next few hours, peaking 08z-11z period. SWOMCD from SPC
indicates this area for development as well on nose of 50 kt jet.
So focus for any strong/severe storms will be in the far
southeast as expected. Freezing level quite high so will need tall
ones to get large hail.


.SHORT TERM...(This evening through Friday)
Issued at 330 PM CDT Thu Sep 21 2017

A couple areas to watch for potential pcpn tonight. One area will
be mainly over northwest minnesota early this evening in zone of
enhanced warm advection ahead of approaching surface boundary
which will reach the northwest by early evening. Appears to be a
weak impulse from water vapor over sw ND which may also assist in
upper support. Convective parameters weak so may be mainly shra vs
T. Of more concern will be later tonight initially over the far
south spreading e-ne during the early morning. During mid- late
evening a low level jet will strengthen with favored convergence
vcnty tri-state border region. This area will also be under zone
of maximized warm advection. Capping may initially retard
development however cap weakens during the late evening. Although
storms will be elevated cannot rule out a few storms reaching
severe limits. Minimum temperatures will remain mild overnight
over all but the far nw with thermal ridge axis in place, warm
advection and low level moisture flux.

On Friday, the frontal boundary will drift to a BDE-ABR line. As a
mid level impulse lifts northeast during the day an associated
surface low will propagate ne along the front reaching the tri-
state border region by evening. Unsure at this time how much
convection will be occuring during the day. Current guidance
hinting that most pcpn during the day will be on the cold side of
the boundary. By late afternoon with approaching wave convection
should initiate vcnty boundary. Convective parameters sufficient
for severe storms and with approaching surface low/triple point
over the far s/se cannot rule out a tornado.

.LONG TERM...(Friday night through Thursday)
Issued at 330 PM CDT Thu Sep 21 2017

Storms which develop Friday afternoon should propagate e-ne
through the evening as the surface low continues to lift along
boundary. With front nearly stationary and precipitable h2o values
of 1.5 inches or greater will have to watch for heavy rainers in
addition to severe.

On Saturday/Saturday night boundary sags to the far s-e forecast
area. Another surface low and upper wave will lift northeast
bringing a continue threat for rain mainly over the southeast half
of the fa.

The upper level low centered around the four corners region will
keep the Dakotas largely in southwest flow aloft continuing to draw
moisture up from the south. Mid level waves of energy will ride
within the southwest flow over the region utilizing the available
moisture. In the low levels, a southwest-northeast oriented stalled
front draped over Minnesota will serve as a focal point for
moisture to overrun upon. Steady rainfall will be possible for west-
central and northwestern Minnesota as well as within southeastern
North Dakota Sunday with a gradual tapering off of rainfall chances
from north to south Monday. The upper level low is then progged to
shift eastward over the region bringing another wave of energy over
the area towards Tuesday, although moisture return will not be as
great as Sunday`s forecast. Conditions finally start to dry around
Wednesday into Thursday as a high pressure builds into the region.

With the forecast area expected to remain on the northern side of
this front along with northerly flow, cool and cloudy conditions are
expected through at least Tuesday with highs remaining largely in
the 50s. Somewhat milder temperatures return Wednesday and Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1147 PM CDT Thu Sep 21 2017

Frontal boundary will limp southeast thru the pd. Creating timing
of wind shift form the south-southeast to northwest issues esp for
GFK/FAR/TVF thru the pd. Other issue will be psbl development of
IFR or low end MVFR cigs near this boundary later tonight and Fri
AM. Kept idea from short range ensemble models of this occurring
and impacting all but KDVL.




SHORT TERM...Voelker
AVIATION...Riddle is the U.S. government's official web portal to all federal, state and local government web resources and services.