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fxus63 kabr 191917 

Area forecast discussion
National Weather Service Aberdeen South Dakota
217 PM CDT Thu Sep 19 2019

Short term...(this evening through Friday night)
issued at 216 PM CDT Thu Sep 19 2019

There are a few challenges for this forecast. Starting with tnt, ll
warm air advection begins in earnest as low level jet returns to the region. With strong
moisture return could see isold/sct convection form overnight,
especially toward and after midnight. Hard to decipher any front,
but old frontal boundary or remnants of front to the south could
advect back north across the region and provide some support for
convection. A broad 15-30 percent chance should cover the situation.
Overnight lows will be mild given low level jet and increasing low level

Friday is where the action begins. A fairly deep mid-level trof out
west should begin lifting northeast toward the northern plains.
Meanwhile, at the surface a front will edge into the western part of
the state. Models seem to have slowed down the progression of both
the upper and sfc systems in the most recent runs, such that the sfc
front won't make it to the Missouri Valley until the evening hours.
Ahead of the front there will be plenty of moisture and instability
per sfc dewpoints well into the 60s, and MLCAPES pushing 2-2.5k
j/kg. Some storms may from initially with diabatic heating out ahead
of the front, but that activity may wane without much in the way of
a consistent lifting mechanism. More widespread convection should
form near the front as it finally starts moving east overnight. Once
again there appears to be some chance for svr/heavy rain, with the
Missouri Valley probably the most likely to see such activity given
proximity to stronger deep layer shear, and the lift of advancing
front. Temperatures will again favor well above normal for most of
the forecast area.

Long term...(saturday through thursday)
issued at 216 PM CDT Thu Sep 19 2019

The period begins with a cold front crossing the region Saturday
morning with showers and thunderstorms expected, mainly in the
eastern County Warning Area. A trailing dryline may bring additional showers midday
Saturday. High temperatures on Saturday will range from the upper
60s, to the mid 70s, or 10 to 15 degrees colder than friday's
temperatures. A 500 mb trough crosses the region Saturday night with
additional showers possible.

An upper level ridge and surface high pressure will slide across the
region Sunday and Monday with dry conditions expected. The ridge and
surface high shifts east on Monday night allowing for a weak low level jet to
develop over eastern South Dakota and western Minnesota. The GFS is showing isolated
pops Monday night into Tuesday morning. The European model (ecmwf) is dry with this
feature. Quasi-zonal flow aloft sets up Tuesday and Wednesday with
dry conditions expected. While models bring pcpn in the forecast
area at the end of next week, they differ with timing and
intensity. Will maintain the in-house model blend which shows low
pops Thursday night.


Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1228 PM CDT Thu Sep 19 2019

VFR skies/vsbys are expected through most of the taf valid period
at all terminals. Late night and early morning showers/storms are
possible, as are low cigs. However, for now have not included any
lower cigs given lack of confidence.


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

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