Scientific Forecaster Discussion
fxus63 kfgf 281403
Area forecast discussion
National Weather Service Grand Forks ND
903 am CDT Wed Jun 28 2017
issued at 859 am CDT Wed Jun 28 2017
Forecast challenge for this morning is monitoring area for any
ponding as areas around Grand Forks County have received over two
inches of rainfall. Areas of concern are between Manvel and
Mekinock as between Northwood and Thompson. Mostly raised gravel
roads in these areas and several calls around the area indicate
the roads are handling these rain amounts. At this point will
spread westward our categorical areas for rainfall and have
increased quantitative precipitation forecast amounts over Grand Forks County.
Update issued at 638 am CDT Wed Jun 28 2017
Forecast in good shape with minor changes to match current
coverage of convective system. Dry slot starting to fill in over
the last hour as 850-700mb moisture convergence has increased
above the central and northern valley as the system wraps up.
Models in good agreement with activity being progressive and
moving east this morning.
Short term...(today and tonight)
issued at 336 am CDT Wed Jun 28 2017
Non-severe mature convective complex moving across the area this
morning with widespread rainfall. Rainfall accumulations expected
to range generally from a quarter to half inch with some higher
locations seeing upwards an inch mainly in northwest Minnesota where the shower
threat persists today. Models in good agreement with the evolution
of the system. The stratiform rain band which extends back to the
west across the Devils Lake basin this morning will slowly move
to the east as the surface low along the South Dakota/ND border tracks to the
east. Ahead of the low an elevated axis of moisture and
instability exists with pwats near an inch and a half and mu convective available potential energy
around 1000 j/kg. As 850mb convergence and warm advection lift
into northwest Minnesota convective redevelopment will be possible through about
noon across the eastern half of the forecast area. Temps will be highest in
the west with more sun than clouds and cooler in the east ranging
from near 70 under the clouds to near 80 in the west.
Thermal profile changes little in the wake of the surface low, as a
result lows are expected to be in the mid 50s for Thursday
Long term...(thursday through tuesday)
issued at 336 am CDT Wed Jun 28 2017
Thursday will start off dry with increasing chances for showers
and storms in the afternoon from west to east with approach of
the next short wave inducing northwest flow aloft. Temps ahead of the
system will rise into the mid and upper 70s Thursday. With the
upper low overhead Friday any clear areas will fill in with
clouds rapidly and temps will struggle to reach 70 with scattered
showers across the entire forecast area.
Saturday to Tuesday...split flow was across North America with
the northern stream over northern Canada and southern stream over
southern Canada/northern states. Long wave trough over the
northern plains shifts to the New England states. Low amplitude
long wave ridge over the West Coast shifts over the northern
plains and flattens by the end of the period.
The European model (ecmwf) was trending slower while the GFS was vacillating. The
European model (ecmwf) was faster early in the period and becomes slower by the end
of the period compared to the GFS. Upper low over the area will
produce showers for Sat/Sat evening.
Little change to high temperatures on Sat, sun and Tue. Mon highs
were increased by one degree from yesterdays run.
Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 638 am CDT Wed Jun 28 2017
Mature convective system to bring rain showers and some thunderstorms and rain at gfk this
morning. Will see the rain activity move east during the day
across the north. Far will likely remain dry whereas bji and tvf
will have rain showers threat much of the next 6 to 12 hours. MVFR ceilings
are possible at gfk, tvf and bji this morning into the afternoon.
Some guidance is even indicating a IFR possibility at tvf and
bji. Will leave out of taf and monitor trends. VFR conditions
expected to develop west to east this afternoon and evening for
the overnight hours.