Area Forecast Discussion
Issued by NWS Rapid City, SD
FXUS63 KUNR 191025
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
325 AM MST Sun Feb 19 2017
.SHORT TERM...(Today Through Monday Night)
Issued at 325 AM MST Sun Feb 19 2017
Current surface analysis shows low pressure over north central
MT, with warm front extending east-southeast across eastern MT
into northern SD. Upper level analysis shows a ridge over eastern
portions of the plains and into the MS river valley, with trough
off the pacific NW coast and a cutoff low over the southwest US.
Southwest flow over the region is bringing considerable mid and
high cloudiness to the area overnight. Cloud cover and warmer air
in place is keeping temps on the mild side, mostly upper 30s to
lower 50s. Low level southerly jet in place is keeping winds on
the breezy side in some favored areas of northeast WY and western
Warm conditions on tap for the area today ahead of shortwave and
cool front passage tonight. Highs will mostly be in the 60s and
lower 70s. Record daily highs could be broken in some areas. Rapid
City record highs of 69 at the airport and 68 in town have a good
chance of being broken. South to southwest winds will continue
through the day, breezy at times across a good portion of the area
by the afternoon.
Shortwave will move into the area this evening, with the best chance
for showers during the overnight hours. Temps look warm enough for
rainfall across much of the area, with a mix possible across the
higher Black Hills later tonight before showers exit. Lows will
mostly be in the mid 30s to mid 40s. Showers will quickly exit
northern and eastern portions of the forecast area Monday morning as
cool front pushes through. Cooler air will filter in, but temps will
continue to be well above average, highs in the 50s and lower 60s.
Mostly sunny skies expected everywhere by midday.
.LONG TERM...(Tuesday Through Saturday)
Issued at 325 AM MST Sun Feb 19 2017
Shortwave ridge briefly moves across the area on Tuesday, with
surface warm front moving east through the area. Warm conditions
expected again, with some record highs in the 60s to mid 70s.
Rapid City record February highs of 75 at the airport and 74 in
town look to be within reach. Another cold front will pass through
Tuesday night. Main shortwave energy will stay north of the area,
but a few showers are possible across northeast WY and the Black
Hills Tuesday night into early Wednesday.
Large scale trough will dig south out of the Gulf of Alaska and into
the Pacific NW Wednesday, then move into the Rockies Wednesday night
and the high plains on Thursday. Latest medium range models now in
somewhat less agreement than previous days with regard to evolution,
timing, and track of upper level system and surface features from
Wednesday night into Friday. There has been a general trend to a
more southerly track of the system by the EC and GFS, with GFS
further south and weaker than the EC, while the GEM is the more
northerly and stronger of the group. Will lean the forecast more
toward the EC at this point with it being more favored by WPC and
also relatively consistent compared to the others. This solution
would favor the more significant snowfall potential to southern
portions of the forecast area, south of Interstate 90, from late
Wednesday night into Thursday night. Still 4+ days out, so plenty of
uncertainty at this point.
.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 325 AM MST Sun Feb 19 2017
VFR conditions are generally expected through the forecast
period. South to southwest winds will be breezy at times across
the area today, especially northeastern WY. Scattered showers will
develop this evening and move through much of the area overnight.
Local MVFR conditions are possible overnight.