481 
FXUS63 KFGF 030448
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1148 PM CDT Fri Aug 2 2019

.UPDATE...
Issued at 1148 PM CDT Fri Aug 2 2019

Clouds continue to hang in in west central MN, so bumped up sky
cover a bit in that area. Otherwise no major changes. 

&&

.SHORT TERM...(This evening through Saturday)
Issued at 255 PM CDT Fri Aug 2 2019

The early morning cloud cover really never went away across the
southern FA, which helped hold down temperatures quite a bit. 
Then there has been a stripe along the highway 200 corridor where
there has been very little cumulus. Along and north of the 
highway 2 corridor the most heating occurred and the most shower 
and weak storm activity formed. Right around the Lake of the Woods
there has been very little cumulus. Overall it looks like various
layers from north to south.

With the best surface heating along and north of the highway 2
corridor, the best MLCAPE values remain there, around 1500 J/kg.
Like mentioned in previous AFDs, there is almost no bulk shear,
which is limiting the storms to being pulsey and weak.
Precipitable water values remain quite high, so if something does
manage to last longer than a few volume scans, it could drop heavy
rain. Generally think it will remain hit and miss weak showers and
thunderstorms until loss of heating later tonight. With some
recent rainfall in a few areas and light winds, there could be
some patchy fog around again toward Saturday morning.

Saturday should be a similar day to today, although south winds 
probably will be a little steadier. Hard to be too confident in 
any lingering showers or weak storms. Since forecast had some 
mentioned in the eastern FA, pretty much left them as is.

.LONG TERM...(Saturday night through Friday)
Issued at 255 PM CDT Fri Aug 2 2019

Biggest thing by Saturday night will be the timing of the next
front. Models currently show it moving into the Devils Lake region
after midnight. If this timing holds, there may be some shower and
storm activity then.

Sunday...Thunderstorm potential will be the main 
impact/challenge. A cold front will be sagging from western 
Manitoba into north central ND Sun morning. Guidance timing 
differences among NAM, ECMWF and GFS are creating/adding to 
forecast uncertainty for Sun aftn and eve. The first two are 
slower and probably offer a more reasonable depiction, moving 
front through the RRV closer to peak heating time. Faster GFS 
would place area to the east, maybe from Lake of Woods to Fergus 
for example, under the more pronounced strong to svr storm threat.

Independent of the actual geography, with temperatures near 
90F and dewpoints near 70F, moderate instability will set up ahead 
of the cold front. Thinking there should be enough low level 
convergence for a few storms to develop, although the lack of large 
scale forcing may hinder storm development. Stronger deep layer 
shear will be lagging the front, and severe potential will depend 
largely on the overlap of the stronger deep layer shear and frontal 
location.  

Monday to Thursday...Northwest flow aloft develops. Expect 
temperatures near normal values, with daytime highs averaging in 
the low 80s. Guidance indicates a mostly dry period given the 
synoptic set up. However, deep layer shear will be sufficient for 
severe storms any day where enough instability develops along with
a well timed weak upper wave within the northwest flow aloft. 
These are the synoptic set-ups during this time of year when 
predictability is quite low.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1148 PM CDT Fri Aug 2 2019

VFR conditions at all TAF sites. Mostly clear skies over the TAF 
sites although some stratus has been hanging on southeast of the 
airports. Several of the models have some fog developing, mainly 
over our south and east, and there has been some 3SM BR developing
already. Have some more 3-5SM towards morning, and brought it 
down to 2SM at KTVF. Possible some spots could get even lower but 
not confident enough to go below 2 miles at this point. Any BR 
will quickly dissipate by mid-morning, with light and variable 
winds starting to pick up out of the south. 

&&

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

$$

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