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Area forecast discussion 
National Weather Service Grand Forks ND
701 PM CDT Sat Aug 30 2014

Update...
issued at 700 PM CDT Sat Aug 30 2014

The current forecast is in good shape. Convective development is
occurring over the western Dakotas ahead of a strong trough. The
low level jet will increase overnight and sustain a fairly strong to perhaps
severe mesoscale convective system into the western areas around 6-9z...then into the
valley in the 10-12z timeframe. There will be strong 850mb
moisture transport and showalters around -3c...along with precipitable waters
rising over 1.5 inches late. Our current grids are dry until
6z...and this timing seems very close...so won't add anything
earlier and monitor overnight.

&&

Short term...(this evening through Sunday night)
issued at 257 PM CDT Sat Aug 30 2014

Current visible showing majority of eastern ND with clear skies
however southeastern County Warning Area still overcast with low clouds that
refuse to break up. Some cumulus is developing in the far NE around
Lake of The Woods and Red Lake. Surface high pressure is currently
over far northwest Minnesota and anti cyclonic flow around high is not helping
bring any drier air into the overcast areas. Return flow is beginning
to increase across central and western Dakotas. Main forecast
challenge for overnight period will be timing onset of warm
advection precipitation. Radar showing showers/storms over northeastern
Montana have struggled to get too far into northwest ND. Models showing minor
inconsistencies with the NAM the driest early...and the GFS/European model (ecmwf)
most bullish with sun PM convection. Will use a forecast blend for
this forecast.

Tonight...high pressure will continue to bring dry weather to the
region through midnight before a upper wave over Pacific northwest will move
across southern Canada/northern Continental U.S. While low pressure ejects into
the plains. An open Gulf will allow strong h850 moisture flux into
the region by late tonight...although not as impressive as 12z
model runs yesterday appeared. Expect some elevated convection by
as early as late Sat evening and increase after midnight. Have
likely probability of precipitation into the western zones after 06z...however main show will be
drg the day Sunday as surface low moves across Dakotas and into Minnesota.

Sunday and Sunday night...models in better agreement with a surface
low kicking out of Wyoming and moving across South Dakota and eventually
into southern Red River valley. There are minor disagreements on exact
speed/track however in general low will move across County Warning Area middle day
with frontal boundary moving into eastern County Warning Area during peak heating
tomorrow. This heating will be dependent..of course...on cloud
cover associated with the approaching low. Short wave prognosticated to be
entering western Dakotas from eastern Montana Sun morning and into Minnesota early
sun evening. Gulf moisture should be readily available with models
showing strong h850 moisture flux into the central and eastern
Dakotas tonight...middle 60 dew points pooling along surface
boundary tomorrow...and 40 to 50 kts of 0-6 km bulk shear.
Associated surface boundary prognosticated to enter the eastern Dakotas (western
cwa) late Sun morning and move across the valley in the early afternoon
hours...extending across northwest and west central Minnesota by middle afternoon. With these
ingredients in place...there is certainly a potential for severe
across Minnesota on Sun afternoon. Storm Prediction Center has issued a slight risk for
tomorrow. Convection should begin tapering off by midnight Sun
night.

Long term...(monday through saturday)
issued at 257 PM CDT Sat Aug 30 2014

A more zonal pattern returns for early next week with minor short
waves bringing some periods of low probability of precipitation Monday afternoon and again
Tuesday...however models not too impressive with any significant
rainfall. Most likely will see some isolated showers and maybe
some thunder Tuesday afternoon.

Tuesday night-Saturday...12z models all agree with a more or less
zonal flow pattern. The best chance for thunderstorms will be Wednesday
night into Thursday as models indicate a stronger upper wave and
associated surface trough. Precipitation cannot be ruled out at other times
given the expected synoptic pattern...but confidence is much lower.
Temperatures likely near seasonal normals.

&&

Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 700 PM CDT Sat Aug 30 2014

There is a band of MVFR ceilings in the southeast that may advect
northward overnight. There will also be increasing southeast winds
ahead of an mesoscale convective system late tonight into Sunday. Winds will shift to the
west/northwest Sunday from west to east by Sunday evening. There will be
showers and storms for all taf sites possible later tonight into
Sunday.

&&

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

$$

Update...dk
short term...speicher
long term...tg/speicher
aviation...dk

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