Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
812 PM MDT Wednesday Sep 2 2015

Update...
issued at 808 PM MDT Wednesday Sep 2 2015

Red flag conditions are ending across parts of northestern Wyoming as temperatures
fall and rh's rise. Thus...have allowed the red flag warning to
expire.

&&

Short term...this evening through Thursday night
issued at 207 PM MDT Wednesday Sep 2 2015

Upper level analysis has ridging over the northern plains with
large closed low over British Columbia. Upper flow over the
northern plains is westerly with mostly sunny skies in place. At
the surface...weak trough of low pressure extends from eastern
Montana through western South Dakota into central Nebraska. Winds
are generally light across the area...and temperatures at 2 PM are
in the middle 80s to middle 90s.

Tonight...upper level flow turns more southwesterly as large upper
low and associated trough slowly dig into the Pacific northwest.
Weak surface trough across the area remains nearly stationary with
weak southerly to southwesterly boundary layer flow continuing.
Temperatures will be fairly mild overnight with lows in the upper
50s and lower 60s across northeast Wyoming...to the 60s to lower
70s across south central South Dakota.

Thursday...ridge amplifies across the central Continental U.S. As the trough
deepens in the west. Southerly boundary layer flow
continues...along with mostly sunny skies and hot temperatures.
Highs will once again be in the 90s with a few spots close to 100
degrees. Late in the day...a weak disturbance will lift out of the
western trough and cross the forecast area Thursday evening. This
could bring some showers and storms to western South Dakota by middle
evening...and persist into the overnight hours. Low temperatures
will continue to be mild...mainly in the 60s.

Long term...Friday through Wednesday
issued at 207 PM MDT Wednesday Sep 2 2015

Models are coming into better agreement with the timing of the
Pacific northwest low and the shortwaves ahead of it...allowing
for a little better definition in probability of precipitation. Thursday night's shortwave
will continue pushing northeastward through the County Warning Area Friday
morning...with best chance for -tsra across central South Dakota then. Next
wave approaches from the southwest Friday evening and brings more
chances of precipitation to the area Friday night and Saturday. Upper low
will strengthen as it pushes eastward Saturday night. Models are
in agreement that 700mb low will track northeastward through
Montana...pushing much of the precipitation north and east of the County Warning Area.
Therefore Labor Day weekend is currently looking a little drier
than previously forecast. Dry weather is expected from Sunday into
the beginning of next week.

Another day of above average temperatures are expected for Friday...with a
gradual cooldown through early next week.

&&

Aviation...for the 00z tafs through 00z Thursday afternoon
issued at 207 PM MDT Wednesday Sep 2 2015

VFR conditions expected through the period.



&&

Unr watches/warnings/advisories...
South Dakota...none.
Wyoming...none.
&&

$$

Update...Johnson
short term...15
long term...pojorlie
aviation...pojorlie
fire weather...Johnson

National Weather Service Glossary of Abbreviations