714
FXUS63 KFSD 111101
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
601 AM CDT Sat May 11 2024

.KEY MESSAGES...

- Temperatures continue to rise this weekend, breaking the 80
  degree mark in a few areas Saturday, and most locations on
  Sunday.

- Scattered thunderstorms will be possible Sunday afternoon and
  evening. Severe weather risks remain low, but gusty winds
  can`t be ruled out with a few storms.

- Temperatures cool closer to seasonal normals next week with
  the coldest highs focused around Wednesday.

- Rain chances increase again late Tuesday through Wednesday and
  then potentially Thursday into Friday. Severe weather risks
  remain low. QPF potential between 0.10 and 0.50".

&&

.DISCUSSION...
Issued at 238 AM CDT Sat May 11 2024

THIS MORNING:  Skies remain mostly clear across the region, leading
to perfect viewing conditions for a spectacular overnight northern
lights display.  Despite the light winds, temperatures remain in the
upper 40s to lower 50s. Sheltered areas are likely to fall towards
the lower 40s by daybreak.

TODAY:   A narrow band of mid-lvl clouds indicates the leading edge
of low-mid lvl warm advection this morning.  These clouds may try to
slide northeast during the day as low-lvl temperatures at the 850
level rise between 11-14C through the day. We`ll mix into the higher
end of the guidance this afternoon with widespread upper 70s to
lower 80 high temperatures. An afternoon scattered CU field may
again develop. Winds remain light, making Saturday one of those
perfect Spring days to be outside.

TONIGHT: Winds stay somewhat mixy overnight which will allow
temperatures to remain in the lower 50s.  An increase in mid-lvl
clouds appears likely.

SUNDAY:  We may see an increase in cirrus overnight as upper flow
trajectories turn to the northwest.  At the surface a fairly weak
and diffuse frontal boundary will drift towards the Tri-State area
in the afternoon.  Low-lvl temperatures again rise 3 to 4 degrees,
which signals a strong potential for highs to climb into the 80s
across the CWA.  Weak surface convergence combined with subtle
700:500 vorticity advection may be enough to trigger widely
scattered convection by mid-afternoon as convective temperatures are
met. MLCAPE values remain fairly marginal given the poor return of
surface dew points, but will likely end up in the 500 to 1000 J/KG.
Mid-lvl lapse rates also remain marginal, so resultant soundings
show fairly tall and thin CAPE profiles.  Shear is also fairly weak,
so no organization is expected.  What may happen are typical Summer-
time thunderstorms, with high cloud bases and deep inverted "V"
soundings suggesting a greater risk for isolated downbursts than
hail.  Would expect this threat to remain very isolated however.

MONDAY: An upper low moving across the Central and Southern Plains
will likely draw moisture away from the Tri-State area Monday, with
a greater chance of the area being influenced by cooler and drier
Canadian air.  Temperatures only rise towards the normal high around
70 degrees for this time of the year.

TUESDAY-WEDNESDAY:   Shortwave ridging moves east into the area
Tuesday, keeping a light surface wind in the place in the morning.
However by the afternoon in response to lee-side trough
development, we`ll begin to see a shifting wind towards a
southerly direction. Scattered convection developing over the
western Dakotas and Nebraska Panhandle Tuesday evening will
track slowly eastward overnight as an initial shortwave moves
northeast across the Dakotas. With the front shoved eastwards
for Wednesday, a secondary shortwave tracking a bit further
south will likely allow renewed development for scattered
showers and thunderstorms into Wednesday. At this point in time,
instability looks rather meager Wednesday, with soundings
showing moist adiabatic lapse rates throughout. The resultant
QPF is also in the lower side, with ensembles focusing the
highest probabilities within the 0.10" to 0.50" range.

THURSDAY-FRIDAY:  A deeper trough forming over southern Canada will
keep the region into a progressive southwest to westerly flow
pattern into the upcoming weekend.  This may spell a continued risk
for scattered rain into next weekend, along with temperatures a
bit above normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 600 AM CDT Sat May 11 2024

A variable wind will turn west to southwest this morning, with
occasional gusts to 15 to 20 mph this afternoon. VFR conditions
are expected throughout the region today, with sounding
suggesting the potential for high based CU this afternoon.

Winds stay below 10 knots overnight, as cirrus moves across the
region into Sunday morning.


&&

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

&&

$$

DISCUSSION...Dux
AVIATION...Dux