Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 161714
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1114 AM CST Thu Feb 16 2017

.SHORT TERM...(Today and Tonight)
Issued at 243 AM CST Thu Feb 16 2017

An upper level ridge builds across the central CONUS today, while a
surface trough deepens over the Plains states, resulting in a
westerly low level flow. In a warm air advection regime with
enhanced mixing, went above guidance, with highs into the mid 50s
from east central SD through the IA Great Lakes area, to the lower
to mid 60s over south central SD and the Missouri river corridor.

Winds transition to a southerly direction tonight as the surface
trough deepens over the western High Plains, and while it will be a
little warmer, very light winds will be more conducive to
radiational cooling. As a result temperatures will still fall into
the lower to mid 30s overnight.

.LONG TERM...(Friday through Wednesday)
Issued at 243 AM CST Thu Feb 16 2017

Generally previous forecast remains valid. The focus again tonight
is on the extreme warmup into next week, the risk for convection on
Monday, and a quick look at a looming storm at the very end of the
forecast.

Overall have bumped temperature back up from blended guidance though
this weekend, and we`ll push near record levels through the weekend.
Even our slight cooldown on Saturday will remain 20+ degrees above
normal.

Rather strong theta-e advection commences late Sunday night into
Monday. Models again continue to show upwards of 200 J/KG MUCAPE
by Monday morning, and with a strong thermal advection gradient
setting up, will introduce isolated thunder wording.

A big story for Monday could be the potential for breaking the
monthly high minimum temperature record for several cities. Current
daily lows for Monday struggle to fall to 50, which would shatter
many records.

The frontal boundary that sweeps through Monday will do little more
than lower dew points. Temperatures Tuesday and Wednesday may again
approach the 60s, potentially setting a streak of 3 consecutive days
of 60 or greater not seen since 2000.

All great things must come to an end however, and we could be seeing
the first signs of change by the 24th, as both GFS/ECMWF show energy
digging into the Central Plains.  Ensembles also support this system
in the mid-section of the country, but fairly high 500mb height
standard deviations centered over the Lower Missouri river valley
could signal some tendency for southern tracks. Lots of time before
this system arrives, so let`s enjoy the mid April temperatures while
they last.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1114 AM CST Thu Feb 16 2017

VFR conditions and light winds will prevail through the period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...JM
LONG TERM...Dux
AVIATION...JH



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