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Area forecast discussion
National Weather Service Grand Forks ND
648 am CDT sun Sep 24 2017

Update...
issued at 648 am CDT sun Sep 24 2017

Adjusted pops as much of the rainfall has shifted westward from
eastern ND into northwestern Minnesota, leaving coverage over west
central Minnesota currently rather sparse. Think this will fill back in
later today as the surface trough axis shifts back to the east and
we could get some development of thunderstorms, some locally
strong to severe as cape values get to near 1500 j/kg with 45 to
50 kts.

&&

Short term...(today and tonight)
issued at 329 am CDT sun Sep 24 2017

Location and timing of heaviest rain will be the primary problem
for the period.

Water vapor loop continues to show amplified southwesterly flow
aloft with several weak shortwaves moving up towards the northern
plains. One such shortwave has already moved into Canada but the
next is over South Dakota and has started to bring another round of moderate
rain showers to the southwestern counties. An inverted trough axis
has returned to the southern County Warning Area and will continue to extend from
the Central Plains into Minnesota today. The frontal boundary will return
further west later today. Rain looks to be concentrated along and
just behind that frontal boundary, with heaviest quantitative precipitation forecast amounts today
expected from southeastern ND up towards Lake of The Woods. Temps
won't recover much and stay mainly in the 50s today. Rainfall
coverage will be a bit less across the southeastern counties but
with some warmer temps in the 70s there will be some weak elevated
instability and some thunder possible.

The main band of precip will move off to the east tonight as the
surface trough and cold front move back into central Minnesota. Have pops
slowly tapering off from west to east overnight. Clouds and precip
will provide plenty of insulation overnight and should keep temps
in the 40s and low 50s even with old air advection.

Long term...(monday through saturday)
issued at 329 am CDT sun Sep 24 2017

Monday and Tuesday...rainy and cool weather will continue as
southwesterly flow aloft continues and eventually the main upper
trough comes out into the northern plains. The upper trough will
move off into Ontario Tuesday night, leaving northwesterly flow
aloft and allowing the area to start drying out. Temps will remain
well below average with highs in the 50s and low in the 40s.

Wednesday through Saturday...Wed continues to look dry as upper
flow shifts to the northwest. Best chance for pcpn during the
late week period with the better chance for showers coming Wed
night into Thu as short wave and associated cold front rotates
through this flow. Afterwards, guidance differs slightly with
timing of northerly flow giving way to some ridging encroaching
from the High Plains. Fri will be dry as flow from the north
brings Manitoba/western Ontario sfc high to the northern plains.

Temps will moderate into the 60s Wed and remain mostly 60-65 through
the weekend. Patchy frost may be possible with the cooler air behind
Thu frontal passage. Lows look to ease below 40 Thu/Fri night from
dvl basin through the northern tier.

&&

Aviation...(for the 12z tafs through 12z Monday morning)
issued at 648 am CDT sun Sep 24 2017

Broad area of rain over all but the kbji area with IFR and lower
ceilings. Visibility down to 4 to 6sm in spots and could go down
to 2sm under heavier downpours. The poor conditions will continue
for much of the day, with the rain band pulling slowly eastward.
Kbji could see some thunderstorms in the afternoon so included
thunderstorms in the vicinity. While there may be some brief improvements to MVFR ceilings
in some areas the conditions will drop back down to IFR by this
evening. Kbji will see some light south winds early in the period
but all other sites will be north to northeast with direction
eventually shifting to the northwest this afternoon.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

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