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Area forecast discussion 
National Weather Service Grand Forks ND
1147 PM CDT Wednesday may 6 2015

Update...
issued at 932 PM CDT Wednesday may 6 2015

No change from previous thinking. Models still not in agreement
with where and when rain will occur...but rain will occur
periodically most areas into Thursday.

Update issued at 640 PM CDT Wednesday may 6 2015

Areas of showers continue to move through the region as upper
waves eject from the main upper low. There will likely be a longer
period of dry vs rainy conditions overnight across most
areas...but will leave the higher probability of precipitation since most areas will
receive precipitation at some point. Otherwise...will wait for the next
update to fine tune the higher probability of precipitation for later tonight into
Thursday morning as the main upper wave moves through the region.

&&

Short term...(this evening through Thursday night)
issued at 315 PM CDT Wednesday may 6 2015

Forecast on track. Main 500 mb low near the Colorado/Kansas/Nebraska
border at middle afternoon. A couple of bands of showers have moved north
through the area so far today...one that moved through this morning now
into Manitoba and the other from Thief River Falls through Grand
Forks toward Valley City. This second band is a bit wider than the
first. There small dry slots in between each band...with a bit
larger dry slot area from entering ecntrl/southeast South Dakota into SW Minnesota. Out
ahead of this dry slot is an arc of showers and isolated thunder from
Ortonville to Mankato Minnesota. Overall...as upper short wave lifts
northeast tonight into Thursday expect bands of showers to
continue to move through the area. At first main rainfall along and
west of the Red River valley...but in time as main short wave
lifts northeast expect heavier rainfall to shift more toward areas
east of the Red River later tonight into Thursday. Entire system
will move east out of the area Thursday night. Rainfall totals in
the 0.50 to 0.75 inch range still looks pretty good...though as
usual some local variations. As for thunder....not looking to
great but did keep in isolated T for tonight all areas as showwalters
do go a bit below zero (mainly southeast ND/west-central mn) in dry slot area
and then east of the Red River Thursday in association with 500 mb
short wave. Look for north-northwest winds to pick up Thursday
afternoon in eastern ND as cooler air moves in. Significantly cooler
Thursday night with a north breeze and lows middle 30s to lower 40s.

Long term...(friday through wednesday)
issued at 315 PM CDT Wednesday may 6 2015

Question will be temperatures and cloud cover Fri-Sat. High pressure and
drier air will drop south and east behind departing storm system
but how far south will dry air make it is questionable. Overall
feel some clearing will make it into the area Friday...though
daytime stratocu will develop...with a mostly clear-partly cloudy
scenario Friday night into Saturday before high and middle clouds return
Sat afternoon. Friday night/Saturday am could see some frost in NE ND/northwest
Minnesota if skies remain generally clear. Forecast lows around 30-32. Some
model guidance shows a few 20s if indeed sky clears completely.

For Saturday night through Wednesday...major 500 mb shortwave trough
axis across central Canada into the 4corners area appears to stay
intact through the extended period... with multiple waves
transiting the area through the late weekend and early part of the
next week. Both the European model (ecmwf) and GFS bring a second Colorado low type
system into the northern plains for the sun-Monday timeframe... but
neither is consistent in pushing widespread rainfall all the way
into the northern Red River valley...while the southern valley is
most likely to get that second heavier rain. Scattered showers are
possible across the area into Tuesday...in the wake of the
departing system. Temperatures should stay slightly below seasonal
normals until Tuesday...until southerly return flow resumes on
Wednesday.

&&

Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1147 PM CDT Wednesday may 6 2015

Anticipate taf sites will be at least MVFR by sunrise...with IFR
possible. Periods of showers will continue through the period as
well. Winds will become northwest and gusty for areas along and
west of the valley Thursday late morning.

&&

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

$$

Update...tg
short term...Riddle
long term...gust/Riddle
aviation...tg

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