Scientific Forecaster Discussion
fxus63 kfgf 191611
Area forecast discussion
National Weather Service Grand Forks ND
1111 am CDT Fri Jul 19 2019
issued at 1110 am CDT Fri Jul 19 2019
Adjustment made to account for current trends on radar, with
scattered showers north and widespread showers south transitioning
east in wake of diminished mesoscale convective system that passed south. Warm front to
our south acting as focus for more organized showers/convection,
with axis of better instability along/south of this front. Morning
severe activity has been remaining south feeding off axis of
better instability with any non-deviant motion within mean flow
showing quick weakening as it approaches our south where
environment is worked over and not as favorable. While we can't
rule out stronger activity this morning clipping our far south
(particularly if there is splitting left movers), but this is a
tough call based on environment and trends so far. Better severe
potential still sets up this afternoon, with potential for warm
front to bulge northward into our south-southeast County Warning Area by early
afternoon. Clearing is uncertain though which lowers confidence on
later activity. Very strong deep layer shear expected to persist
potential is there for a few stronger storms or even supercells to
quickly develop this afternoon. As cold front continues to
progress eastward window Narrows and by late afternoon threat
should be over. Will need to monitor evolving trends.
Update issued at 648 am CDT Fri Jul 19 2019
No changes at this update.
Short term...(today through saturday)
issued at 348 am CDT Fri Jul 19 2019
Water vapor loop indicate an upper low over the southern Alberta/Saskatchewan
border and a second upper low was over NW Washington.
An mid level trough over se Montana will move across the southern Red
River valley this afternoon. Atmosphere forecast to be quite
unstable south of the area and over the far southern zones this
afternoon. Warm frontal boundary over South Dakota and southern Minnesota will move
north into central Minnesota this afternoon.
More stable air moves in from the west over the northern part of the
forecast area today. Model soundings indicate some cooling occurs in
the lower layers while some warming occurs aloft. Not so in the far
southern Red River valley where moisture increases in the lower
layers and some drying occurs aloft. Low level jet over southwest Minnesota
shifts to the east this afternoon.
The next short wave will move across northeast South Dakota late Fri night and
Sat morning and produce a threat for showers/thunder in the far
south Fri night.
Long term...(saturday night through thursday)
issued at 348 am CDT Fri Jul 19 2019
Saturday night through Sunday...flow begins to transition to
northwesterly across the northern plains. There is decent agreement
on a reinforcing shortwave coming across ND on Sunday, but the
operational GFS breaks out quite a bit of precip while the European model (ecmwf)
doesn't have much at all. Not a lot of moisture to work with and the
operational GFS is a wet outlier on the gefs plumes, so will keep
precip out for the time being. Temps will be a bit cooler than
average with highs in the 70s.
Monday through Thursday...strong upper ridge builds over the
northern rockies, leaving our region in dry northwesterly flow.
Temps will be warming back up to near to above average as the ridge
axis slowly shifts eastward. There are signs of the ridge breaking
down with a shortwave coming over the top of it by the end of the
period, but confidence is not very high on timing. Kept the minimal
pops that the blend gave US.
Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 648 am CDT Fri Jul 19 2019
VFR conditions were across the area with cigs at or above 7 thousand
ft. Expect VFR conditions for today and tonight. Obviously MVFR to
IFR conditions can be expected with thunderstorms.