Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 191542 AAB

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1042 AM CDT Sun Mar 19 2017

Issued at 1035 AM CDT Sun Mar 19 2017

Frontal boundary has crossed central SD with both KPIR and KMBG
having gone to a northwest wind. Will be watching progression of
front through the day, with increasing northwest winds over
central SD, thus increasing the fire danger. Seeing quite a bit of
cirrus moving through the region, thick at times, so it will be
interesting to see if this has an effect on high temperatures.
Will not make any changes to highs at this point, although many
sites are rising rather slowly. Banking on modest mixing this
afternoon to allow temps to range from the upper 50s to lower 70s,
with the warmer temps over central and south central SD.


.SHORT TERM...(Today through Tuesday Afternoon)
Issued at 352 AM CDT Sun Mar 19 2017

The surface pressure pattern across the area this morning remains
fairly tight with breezy southerly over most of the CWA. The
winds have kept temperatures from falling with most locations in
the 30s and 40s.

An area of low pressure over central Saskatchewan and upper
level ridging will bring abnormally warm temperatures into the
region today. The combination of temperatures at 925/850 mb between
the 75th and 99th percentile and a weak trough passing through the
region should produce highs in the upper 50s, to the mid 70s. The
warmest temperatures will be felt along and west of the Missouri
River where better mixing winds will occur. While afternoon RH
values will fall to the 20 percent range, northwesterly winds this
afternoon should fall short of red flag criteria.

A surface high pressure building into the region later tonight
should bring dry conditions to the area. That said, a weak upper
level system could bring light pcpn along the ND/SD border. On
Monday, a stronger Canadian high pressure will begin sliding
southward with a dry northeasterly flow setting up over the NE
portion of the CWA. Meanwhile, a surface low over Colorado will
bring increasing LLM into southwestern SD. An upper level
shortwave will ride along this moisture gradient with pcpn likely
for the SW portion of the CWA Monday night through Tuesday
morning. While pcpn should begin as rain, there will be a
transition over to snow with 1-2 inches possible.

.LONG TERM...(Tuesday Evening through Saturday)
Issued at 352 AM CDT Sun Mar 19 2017

The suite of 00Z models and their corresponding guidance remains
resolute in generating some low end measurable precipitation by
Wednesday afternoon, as a mid-level shortwave attempts to top the
upper level ridge translating east over the central and northern

All the models are also bringing measurable precipitation to the CWA
on Thursday in a waa regime (southwest flow aloft). A significant
upper level low pressure system is still progged to move out of the
Rockies and onto the Plains states Thursday night into Friday. And,
the 00Z GFS/Canadian solutions are still the most progressive with
all this longwave trof energy crossing the plains, indicating a low
track that would place some of the system`s deformation zone
precipitation over the far southern and southeastern forecast zones.
The 00Z ECMWF output, while also still equally progressive pushing
the entire longwave trof across the country`s mid-section, maintains
a low track and deformation zone farther south and east, keeping
most of the Thursday night/Friday precipitation potential away from
this CWA.

At this point, given the WAA pattern forecast to be in place during
the out periods, most of the precipitation type being generated in
this extended forecast package is rain. Superblend guidance was
accepted for pops/weather grids, which continues to yield some
fairly hefty pops with the Thursday through Friday precipitation
potential. Would still like to see the ECMWF generating a more
northerly track and location for deformation zone-forced
precipitation, like the GFS and Canadian, before being sold on this
scenario directly impacting the southern or southeastern portion of
the CWA.


.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 641 AM CDT Sun Mar 19 2017

VFR conditions are expected at all locations through today and
tonight. A cold front passing through the region today will switch
the strong southerly winds around to breezy northwesterly winds.




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