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Area forecast discussion 
National Weather Service Aberdeen South Dakota
337 am CDT sun Apr 19 2015

Short term...(today through Tuesday afternoon)
issued at 334 am CDT sun Apr 19 2015

Showers will gradually end from west to east this morning as drier
air moves in behind the passage of a surface cold front. The
current showers should exit this County Warning Area before 18z...with a few hours
of dry conditions likely. While precipitation will end...gusty
northwesterly winds will develop with the strongest winds
occurring along and west of the Missouri River. Sustained winds
of 25 to 35 miles per hour with gusts around 45 miles per hour are likely West River
this afternoon. Around 21z various hi-res models show instability
showers thanks to steep low level lapse rates and weak cape
values...moving into this County Warning Area from North Dakota. These showers
should diminish shortly after sunset.

An area of high pressure building into the region from the
northwest will increase the pressure gradient on Monday...especially
in the eastern half of the County Warning Area. Half km winds suggest a Wind
Advisory would be needed for the James River Valley and points
east. Also...the NAM shows instability showers developing around
21z along the I-29 corridor. This seems possible based on cape
values around 150 j/kg and steep low level lapse rates. The
previous forecast had chance probability of precipitation in the east which looks good
overall. The rest of the period will be cool and dry. Lows Tuesday
morning could range in the 20s for most locations.

Long term...(tuesday evening through saturday)
issued at 334 am CDT sun Apr 19 2015

The longer range solutions are generally similar. Aloft...the
European model (ecmwf) and Canadian models propagate the ridge/trough pattern
eastward during the period...allowing for the potential for short wave
energy to move east-northeast toward the region during the second
half of the period. Superblend continues with its low end probability of precipitation
mainly across portions of the southern half of the County Warning Area from
Thursday night through Saturday. the lowest
kilometer of the atmos...low level flow continues to support the
advection of coolish dry air down out of Canada on the nose of a
surface high pressure system prognosticated to move very little between
Tuesday and Saturday. The somewhat more progressive European model (ecmwf) suggests
that by Friday...surface high pressure has shifted east enough to
allow for return flow southerly winds and slightly warmer temperatures by
the end of the period versus the GFS output.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 1249 am CDT sun Apr 19 2015

An upper level low pressure trough sliding across the northern
part of the region tonight along with a strong cold front moving
through will continue to bring showers into Sunday morning. Behind
this front...very strong northwest winds will develop as cold air advection kicks
in and the mixing layer deepens. Expect northwest winds at 20 to
25 knots with gusts to 35 to 40 knots at all locations late
tonight and Sunday. Also...expect low VFR/high MVFR ceilings to
slide across the region into Sunday morning. With the cold air advection on
Sunday along with a little instability building up...expect some
more showers to develop on Sunday afternoon ending Sunday evening.
These may affect the taf locations.


Abr watches/warnings/advisories...
South Dakota...Wind Advisory from 11 am CDT /10 am MDT/ this morning to 8 PM CDT
/7 PM MDT/ this evening for sdz003-015-033>035-045-048.



Short term...South Dakota
long term...dorn

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