Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 130428
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1128 PM CDT Sat Aug 12 2017

.UPDATE...
Issued at 1121 PM CDT Sat Aug 12 2017

No changes necessary.

UPDATE Issued at 948 PM CDT Sat Aug 12 2017

Based on current radar trends and guidance from the HRRR have
trimmed back on pops across the north through midnight. Still
unsure of coverage across the north as upper low drops through so
maintain low pops later tonight. The far s-se will see a break
until the next band moves in aft midnight.

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 06Z TAFS through 06Z Sunday night)
Issued at 1121 PM CDT Sat Aug 12 2017

Rain coverage continues to be a challenge mainly on how far north
any rain will get. Models have been overdoing rain coverage all
evening so some doubt as to if any -ra will reach GFK/DVL taf
sites. At this point limited any mention to FAR and will have to
monitor trends. Best potential looks to be towards morning as
upper low reaches the forecast area. Also limited any mvfr cigs to
FAR leaving the remainder sites vfr through the period.

&&

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

$$

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



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