Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
711 am CDT Sat may 23 2015

Update...
issued at 705 am CDT Sat may 23 2015

Hrrr was right on the Money with some light rain showers spreading
northeast through ecntrl/southeast South Dakota into SW Minnesota. These will move
northeast...it remains to be seen how they hold together.

&&

Short term...(today through sunday)
issued at 327 am CDT Sat may 23 2015

Issues will be how far and when will the precipitation spread north the
next few days. Larger upper trough over Utah/north Arizona this
morning. This will slowly move east the next few days..as moisture
continues to move north. The northern edge of high level cloud
cover will spread over the area today with some middle clouds in the
southern forecast area this afternoon. Of interest is a small area of showers in
the Sioux Falls area. Hrrr and a few other short range models do
bring a few spits of precipitation northeast into west-central Minnesota (alex-St
cloud area) late morning into early afternoon. To blend with weather forecast office mpx I
did insert a few sprinkles in Otter Tail and Wadena counties late
morning into middle afternoon. Based on moisture moving north any showers
will not reach the South Dakota/ND border area until late this afternoon and
trimmed probability of precipitation accordingly for today. Tonight will see a shower Rick
in the south but stubborn high pressure to the north along the
Canadian border will remain in place slowing down any northward
advancement of moisture.

Sunday will see deeper moisture start to move into southeast ND and then
spread north during the day. Thus higher probability of precipitation...mostly southern
forecast area. GFS remains a bit faster than European model (ecmwf)/Gem which keep
dvl-gfk area dry through sun evening.

Long term...(sunday night through friday)
issued at 327 am CDT Sat may 23 2015

Rain chances spread north Sun night with high rain chances Monday
as upper trough and surface low move from southern South Dakota into central/southern
Minnesota. High pressure does remain over southern Manitoba and some
models want to keep far northwest forecast area dry even Monday. At this time
went with superblend of models and idea of categorial probability of precipitation for
showers Monday southeast 2/3 of the forecast area. Some weak
instability...but very weak...so did keep slight chance of thunder
Sun night through Monday in the grids. Precipitation begins to move east Monday
night. As for how much rainfall....most areas in the one half to
three quarters inch range gfk south and east and less northwest.

For Tuesday through Friday...
not a lot of agreement among models although they do all show the
potential for thunderstorm activity. Upper features become out of
phase when comparing European model (ecmwf) and GFS...unchanged from yesterday's
solution. European model (ecmwf) has longer waves with more of a southwest flow middle
week while GFS hangs on to a digging shortwave north of the border
with more of a zonal flow over the northern plains. Amount of
moisture return will be key to coverage and intensity of storms.
Latest extended superblend solution continues with probability of precipitation covering
most of the forecast area most of the time...only adjustment was to
smooth out minute areas of precipitation/no precipitation within the fgf County Warning Area.
Temperatures will be near normal values with daytime highs mostly in
the 70s.

&&

Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 705 am CDT Sat may 23 2015

VFR through 12z sun. Expecting an increase in high and middle level
cloud cover today...thickest in the southern Red River and west-central Minnesota. South
winds generally near 10 kts. No precipitation put in the tafs through 12z sun
as best chance is beyond then.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

Update...Riddle
short term...Riddle
long term...wjb/Riddle
aviation...Riddle

National Weather Service Glossary of Abbreviations