Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 210440
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1140 PM CDT Thu Jul 20 2017

.UPDATE...
Issued at 1140 PM CDT Thu Jul 20 2017

Beefed up cloud amounts a little more through the rest of the
night, otherwise not too much going on yet. High resolution models
still show the potential for isolated/scattered showers with
isolated thunder overnight. However, overall confidence is pretty
low much will occur.

&&

.SHORT TERM...(This evening through Friday)
Issued at 321 PM CDT Thu Jul 20 2017

The narrow band of elevated showers has now weakened enough to not
be detected by radar. Otherwise full sun with temps in the upper
70s to mid 80s over the area. No cumulus due to capping issues but
do have instability present more so rooted 800-700 mb. Upper level
moisture plume combined with a short wave entering NE Montana and
seeing resultant convection form in a region of mid 90s
temperature and mid 50s-low 60s dew pts. Expect storms to increase
in far W ND and esp NW ND ahead of the short wave moving in and
with capes in the 2-3k range some severe likely in that area. For
eastern ND most all models do take some convection east-northeast
into at least DVL basin this evening but unsure how strong as
conditions not quite as unstable, but as we saw this morning
enough mid level based instability to keep storms going. Later
tonight as low level jet kicks in and we keep that instability
layer just above the sfc will likely see continued development of
pockets of showers/t-storms, esp north half of the fcst area into
southern Manitoba.

Friday is uncertain in regards to how it will play out. Idea
currently is for isolated-scattered convection during the day
psbl, with some severe risk in E ND. But how any late night/early
AM precipitation and cloud cover plays havoc with Friday will
determine extent.

.LONG TERM...(Friday night through Thursday)
Issued at 321 PM CDT Thu Jul 20 2017

Now more likely is for severe storms to form upstream friday late
aftn/eve nr SK/MB border region to the southeast of an upper level
short wave and then form a complex and drop southeast into the
area overnight Friday night. Wind threat would appear to the main
issue. Morning convection esp in northeastern fcst area Saturday
should exit the area but will need to watch position of a frontal
boundary to see if any additional storms can re-develop in the
aftn in the lake of the woods region.

Breezy northwest winds Saturday behind this system for E ND into
WC MN. Sunday is looking a bit cooler at this point and dry.

Strong WAA Mon night pushing through eastern FA ushering in next
rw/trw chance after a mainly sunny and seasonably warm Mon.
Convection may continue into Tue as upper wave approaches from
Saskatchewan. Decreasing POPs maintained for Wed but best guess
(with guidance mainly in agreement) is for the bulk of the action to
push east of the area during the morning succeeded by a drier
afternoon. Upper ridge begins to build again Thurs from Rockies
toward high plains with sfc high stretching from Manitoba south into
the northern plains.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1140 PM CDT Thu Jul 20 2017

May be some isolated or scattered showers/thunder overnight, but
confidence pretty low to include much in the TAFs. Think the mid
and high level clouds will eventually clear out later Friday
morning, allowing heating to occur. The 00Z NAM/GFS show
convection breaking out along the surface boundary near the Devils
Lake area around 21Z Friday, then tracking the storms east-
southeast through the late afternoon and evening. Used this
guidance for preliminary timing in the TAFs, but only went VCTS
for now as overall confidence is still fairly low. Will try to
refine the thunder threat in the TAFs with later issuances.

&&

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

$$

UPDATE...Godon
SHORT TERM...Riddle
LONG TERM...WJB/Riddle
AVIATION...Godon



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