Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kabr 132331 aaa 
afdabr

Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
631 PM CDT sun Oct 13 2019

Update...
issued at 629 PM CDT sun Oct 13 2019

The forecast is on track this evening. Made a few minor tweaks to
sky cover to slow down clearing, but otherwise no changes were
needed.

&&

Short term...(this evening through Monday night)
issued at 314 PM CDT sun Oct 13 2019

A bit of a tricky forecast setting up tonight as some residual cloud
cover will be hanging around which will have a play into how far
temperatures fall overnight. Through the day today, we've seen
thicker, more widespread cloud cover thinning across East River
zones in our County Warning Area. Temperatures have been responding faster with more
sunshine in our western zones as readings have reached the 40s. Most
of the eastern areas have been stuck in the 30s.

This cloud cover still all part of the large, cyclonic circulation
from the upper low across southern Ontario. As we move through the
rest of today and into the overnight, sfc high pressure will slide
across the forecast area. Our winds should become fairly light
overnight. Some of these leftover clouds are anticipated to stick
around tonight from the James Valley and points east. More clearing,
if not clear skies will be more long lived through the night across
the Missouri Valley. But, there could be some breaks in the clouds
in the east as well. A weak waa pattern develop early tomorrow
morning as well. So, this presents a challenge to tonight's lows.
Played conservative and hedged between the coldest and warmest
guidance. In addition to the chilly temps, do think some patchy fog
will develop toward early morning across the James Valley areas as
llm remains high with the new/melting snow cover. We begin to turn
the corner on early winter on Monday as southerly flow kicks in and
temps begin to moderate. Although highs will still fall below
normal. A new system and associated cold front enters the picture
late in this period. However, it looks to remain mostly dry as it
begins to pass through.

Long term...(tuesday through sunday)
issued at 314 PM CDT sun Oct 13 2019

On Tuesday, pretty good pressure gradient is in play and mixing
layer winds should prove rather blustery. There is some low level
cold air advection happening on Tuesday, too, so looking at high temperatures
Tuesday remaining way below normal, probably in the upper 30s to mid
40s. There is the potential for some wrap-around (trowal-forced)
light showery-type precipitation Tuesday into Tuesday evening,
mainly for areas of the County Warning Area north of U.S. Highway 212.

Otherwise, the forecast is dry all the way through the end of the
week, aided by the building of a large upper level ridge across the
central Continental U.S. Tuesday night through Thursday. Heights are falling by
the end of the week into the weekend with steering flow winds aloft
re-orienting to more of a west-southwesterly direction. It's
probable that a couple S/w's are working across the region between
Friday and Sunday. There are some low pops in for Saturday night and
Sunday, but low confidence right now that there will be much in the
way of precipitation developing/occurring over this cwa, given the
amount of ongoing disagreement in deterministic solutions and the
spread showing up in ensembles output.

It does still look as though deterministic and ensemble solutions
support a warm up in the low levels that gets started across the
western half of the County Warning Area on Wednesday and then spreads east across
the rest of the County Warning Area Thursday, with a warm airmass persisting through
Saturday.

&&

Aviation...(for the 00z tafs through 00z Monday evening)
issued at 629 PM CDT sun Oct 13 2019

MVFR cigs will exit the east by late tonight. VFR conditions are
expected to prevail after that, except for the possibility of some
IFR fog near kabr Monday morning.

&&

Abr watches/warnings/advisories...
South Dakota...none.
Minnesota...none.
&&

$$

National Weather Service Glossary of Abbreviations