Area Forecast Discussion
Issued by NWS Sioux Falls, SD

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KFSD 261708
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1208 PM CDT Wed Jun 26 2019

.SHORT TERM...(Today and Tonight)
Issued at 407 AM CDT Wed Jun 26 2019

Numerous complexes of storms moving across the High Plains early
this morning.  As the complexes work east, they continue to move
into increasingly stable air.  Therefore, expect the complex near
the highway 14 corridor to struggle, but could produce some brief
rain.

Storms in Central Nebraska near the I-30 corridor not handled
well by the short term hi res models, but lifting from near 800 mb
resulting in near 2000 J/kg of elevated CAPE. Could see a few storms
develop along the highway 20 corridor this morning as weak warm air
advection could lead to develop under a very weak cap. Shear is
fairly unidirectional, but with substantial CAPE could see a storm
or two approach severe limits with steep lapse rates aloft leading
to a hail threat and dry sub cloud layer leading to a wind threat.

Expect the bulk of the day to be dry today, as boundary across
Nebraska into Iowa lifts north.  Right now, models are fairly quick
in lifting the boundary to the north, but think the boundary may not
lift as far north as models are currently suggesting because of the
convection across eastern Nebraska.  This will impact temperatures
slightly today, but more convective chances tonight. Some of the
models develop stratus throughout the day as moisture becomes
trapped below the elevated mixed layer.  Have sided with partly
cloudy skies, but if stratus does develop may need to adjust highs
accordingly.

As weak shortwave moves into the plains later this afternoon, expect
thunderstorms to develop across western Nebraska.  This area of
convection is expected to organize into a complex and follow the
boundary into central and eastern South Dakota. Main threats with
this system will be large hail and damaging winds.  Have focused
highest pops north of I-90, where the nose of the low level jet is
focused. With this complex of storms working into an unstable
environment, and encountering better shear with time as the low
level jet develops, expect severe potential to remain throughout the
overnight hours as complex shifts east.

.LONG TERM...(Thursday through Tuesday)
Issued at 407 AM CDT Wed Jun 26 2019

Behind the complex, models are beginning to hint at the stratus
potential with easterly winds developing in the near surface layer.
Lowered forecast highs on Thursday by blending the National blend
with CONMOS. This is not as cool as the NAM and GFS would suggest.

Substantial warm up still expected for the weekend with temperatures
soaring well into the 90s, and with dew points near 70, have heat
indices of 100-110 during peak heating on both Saturday into Sunday.

Short wave moving into the Northern Plains may initiate an additional
round of thunderstorms Sunday night, and may cool temperatures
closer to normal. Will need to keep an eye on lingering boundaries
next week as they may be the focus for additional convection.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1205 PM CDT Wed Jun 26 2019

VFR conditions persist into the evening hours. Will be monitoring
convection that develops over western South Dakota and the
Nebraska panhandle later this evening. Latest convective trends
continue to support this convection moving northeast along a
stalling boundary. Will increase wording in TAF for increasing
confidence in convection. Strong winds will be a risk for all
aviation locations.

Thunderstorm activity will slide east after daybreak, but could
linger along the low level jet axis over SW MN and NW IA into
mid-morning.

&&

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

$$

SHORT TERM...BT
LONG TERM...BT
AVIATION...Dux


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.