Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 122357
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
657 PM CDT Sat Aug 12 2017

.UPDATE...
Issued at 654 PM CDT Sat Aug 12 2017

Trimmed pops over the DVL basin where returns are having a tough
time staying organized. Otherwise forecast on track at this point.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 250 PM CDT Sat Aug 12 2017

Main challenge for the short term will be heavy rain potential
across the south. In general models continue to push south the
heaviest precip into northeastern SD and southwestern
MN...although Grant County up into Otter Tail county still seeing
potential for one to one and a quarter inch of rain fall.
Elsewhere looking at one half to an inch of rain along and south
of the I-94 and Highway 10 corridor.

Upper low over w cntrl ND will drop into the southern valley by
12Z Sun as an inverted trough associated with sfc low pressure
over far s cntrl SD extends NE into sw/w central MN. A 35 to 45
kt low level jet will push north into the Watertown SD/Madison
MN area...with the heaviest precip amounts per 12Z NAM being along
a Watertown SD to Morris MN axis on the nose of the llj. This
heavier precip band is further south than prev forecast hence
slightly lower amounts across southern zones. Showalters increase
to positive roughly north of Fargo and generally keeping showery
activity with isold thunder for p-type overnight. Main precip ban
on Sunday then moves into the Alexandria area during the morning
and on into Brainerd in the aftn...with the NW edge clipping my
far sern zones where storm total QPF values exceed an inch due to
the longer duration of precip over this area. Overnight lows
tonight in the mid 50s and the coolest Sunday highs over the
southeast, where rain and isold thunder will limit daytime highs
to the mid 60s. Areas across the north will reach the upper 70s
with more solar available.

.LONG TERM...(Sunday night through Saturday)
Issued at 250 PM CDT Sat Aug 12 2017

(Sun night - Tue)

Short wave will exit the area by Monday, followed by a weak bubble
of high pressure that will prevail during the daylight hours. The
next system will begin to affect the western FA by late Monday
night. Timing differences exist between the GFS and the ECMWF with
the latter being much quicker initiating convection during the
morning on Tue. Given that the GFS is usually the faster model and
this time is more laggard, believe that we`ll favor it with a slower
solution this time.

(Wed-Sat)

CAPE values will be modest overnight Tue into Wed (still favoring
the souther forecast area) but stronger low level forcing in the
vicinity of frontal boundary should yield areas of shwrs/tstms with
particular focus farther south. The GFS slowly moves the main upper
trough through the area Wednesday and Wednesday night, bringing more
precipitation to MN during this time. The next precipitation
opportunity will present itself on Fri as a healthy wave traverses
the Northern Plains. Temperatures throughout the upcoming week
should stick very close to mid August averages.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 654 PM CDT Sat Aug 12 2017

Best shower potential will be over the FAR site where tempo/vcsh
groups added. Elsewhere potential looks limited at this point as
rain having a tough time holding together much north of I94.
General VFR cigs/vsby through most of the period. Some indications
of mvfr cigs over the west and south tomorrow morning.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

$$

UPDATE...Voelker
SHORT TERM...Speicher
LONG TERM...WJB
AVIATION...Voelker



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