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Area forecast discussion 
National Weather Service Grand Forks ND
1141 PM CDT Tuesday Sep 1 2015

issued at 1136 PM CDT Tuesday Sep 1 2015

Other than a patch of middle level clouds over the central Dakotas no
indications yet of any convective development. Low level jet
remains focused on SW Minnesota where ongoing deep convection exists.
Will maintain low probability of precipitation as weaker jet developing over S central ND.
No changes to current forecast.

Update issued at 941 PM CDT Tuesday Sep 1 2015

Thunder chances still the challenge tonight. The hrrr which was
overly aggressive in developing storms over our western forecast area has now
backed off and focusing development over SW Minnesota where the more
prominent low level jet is taking shape. A few of the short range
models continue with some modest development later tonight so will
keep slight chances going as nocturnal development sometimes
fickle. Best low level moisture flux is over the western forecast area so
have added some patchy fog to this area as a start.

Update issued at 645 PM CDT Tuesday Sep 1 2015

No changes needed this update period.


Short term...(this evening through Wednesday night)
issued at 325 PM CDT Tuesday Sep 1 2015

500 mb short wave noted in southeastern South Dakota moving
northeast. A band of showers are with this system. For tonight
question is precipitation chances overnight into Wednesday morning mainly for
NE ND into northwest Minnesota. For the past couple of days models have
indicated threat for some convection to develop near 06z in the middle
Red River and the move northeast through Lake of The Woods region by
12z. 12z models today show to some degree the same thing...but
more GFS in this case as most short range models such as the hrrr
and rap dont show (at least with midday and early afternoon runs).
There is an impressive low-850 mb moisture return this evening-
overnight. Seeing 70 dew points along the South Dakota/ND border into the
Alexandria area while most of our forecast area has dew points in the
50s. So will see a moisture surge tonight and instability increase
in the 850 mb layer 06z-12z period when a few hundred 850 mb cape
available. Problem is low level jet is very weak 20 kts maybe. But
will side with consistency and keep low probability of precipitation in but have them
06z-12z....extending them a few hours past 12z in Lake of The
Woods. Wednesday will be much more humid and warm.

Long term...(thursday through tuesday)
issued at 325 PM CDT Tuesday Sep 1 2015

Hot and humid on Thursday with middle 80s east to low 90s west. Will
maintain a low threat for precipitation late Thursday night in eastern
ND...then keep chance probability of precipitation on Friday. Uncertain how event will play
out but will have several short waves and surface lows move northeast
along a frontal boundary which will be over or near our area. Each
one giving good chances for showers and thunderstorms starting
late Friday. Day to day timing of course is difficult at this

Saturday to Tuesday...models in good agreement with the general
500mb southwest flow aloft and evolution with a closed strong short
wave moving over the northern plains early next week. As a result an
active weather pattern with several rounds of convective activity
can be expected for the region over the Holiday weekend.
Uncertainties exist with the timing and placement of the lead wave
and the stronger short wave on Monday. Currently a lead wave is
expected to bring a round of thunderstorms Friday night with another
round Saturday night before the the lighter wrap around precipitation on
Sunday afternoon and early Monday. Given the ample moisture in
place...precipitable waters approaching 2 inches...heavy rain will be possible
with any storm. Temperatures will be warmest on Saturday with low
80s in the southeast half of the forecast area and 70s in the northwest...highly influenced
by expected cloud cover. A cooler...closer to average temperature regime is
expected with 70s Sunday to Tuesday behind departing short wave.


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1136 PM CDT Tuesday Sep 1 2015

Convective development overnight remains too uncertain to mention
in any tafs. Did mention some br development towards morning as
low level moist air continues to spread northward.


Fgf watches/warnings/advisories...


short term...Riddle
long term...jk/Riddle

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