Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 08/29/22
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1042 PM CDT Sun Aug 28 2022
.SHORT TERM...(This Evening through Monday)
Issued at 222 PM CDT Sun Aug 28 2022
KEY MESSAGES:
1. Conditional risk for convection late this evening.
2. Scattered light showers/sprinkles into Monday.
3. Generally dry and pleasant for the first half of the week.
4. Warmer, a few more clouds, and dry into next weekend.
THIS AFTERNOON: A stubborn stratus deck all morning has slowed down
the upwards progression of temperatures this afternoon ahead of a
quickly approaching frontal boundary. Ahead of this front, most of
the CU that has developed remains flat and showing no signs of
upwards growth. That said, still anticipating MLCAPE values upwards
of 3000 J/KG to develop along and ahead of this front by late
afternoon. The problem is going to be the lingering inhibition,
and upper forcing oriented to the northeast of the forecast area.
ACARS sounding from FSD around 1730Z indicated that 850 mb
temperatures were above 27C, with 700 mb temps near 12-13C with
some signs low-lvl moisture is not quite sufficient in the low-lvl
yet. This warm airmass will continue to advect into SW Minnesota
through the afternoon, and based on the latest CAMs would push the
highest potential for strong convection northeast of the CWA
given our inability to reach convective temps. That doesn`t mean
we can`t have some weaker multi-cell activity try to develop, but
that convection may fail to mature. If it does mature, the
marginal effective shear AOA 20 knots would only support multi-
cells with potential for large hail and a few bowing segments.
Further west, temperatures behind the front will begin to fall
into the evening. Some gusts over 25 mph may be possible behind
the boundary as much drier air moves southeast.
THIS EVENING/OVERNIGHT: While the lift may be much weaker, can`t
rule out an isolated elevated storm late this evening over portion
of NW Iowa as the low-lvl front arrives. This activity could present
a large hail risk briefly before moving away from the CWA. 925:850MB
cold advection continues through the overnight hours, but those
overnight temperatures may be held up by the increase in 700:600 mb
RH and cloud cover. A weak corridor of mid-lvl frontogenesis may
drift through the Missouri River valley into Monday morning. A good
deal of dry air in the sub-cloud layer, but forcing may be strong
enough (along with a small amount of instability) to produce a few
SHRA/TSRA or sprinkles into mid-morning.
MONDAY: Cloud cover will slide eastward on Monday leaving a very
nice day for Monday. Northwest surface winds may be a bit breezy at
times during the day, but temperatures warm near normal and humidity
will be much lower. Some afternoon diurnal CU is likely.
.LONG TERM...(Monday Night through Sunday)
Issued at 222 PM CDT Sun Aug 28 2022
TUESDAY-WEDNESDAY: Winds weaken through the day on Tuesday as
high temperatures climb near seasonal normals once again. High
pressure and a lack of forcing will lead to dry conditions. A bit
more mid- lvl cloud cover may move in for Wednesday as models
indicate a subtle mid-lvl trough moving through the Northern
Plains. This moisture starved system only produce a minor
influence on temperatures.
THURSDAY-FRIDAY: Low-lvl warm advection begins to develop for the
end of the week leading to a slight rise in temperature above normal
Thursday and Friday. Winds may be a bit gusty on Thursday, and with
dry conditions and drying fuels, we`ll need to start watching fire
weather conditions. Both GFS/ECMWF indicate a weak front settles
into the region for Friday. Again, the forcing looks weak overhead
of this feature, and low-lvl moisture remains marginal, so at most
some increase in cloud cover and perhaps a few isolated showers
could be possible.
SATURDAY-SUNDAY: Really no change to the synoptic pattern moving
into next weekend. Most of the Northern US remains stuck under a
fairly stagnant mid-lvl flow pattern, indicative of weak shear and
poor moisture return. The biggest question mark may be temperatures
and if a slightly cooler Canadian high can slip into the western
Great Lakes by Saturday. Temperature remain near to perhaps
slightly above normal, with mostly dry conditions.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1042 PM CDT Sun Aug 28 2022
A cold front is expected to be east of SLB and SPW by 06Z. No
thunderstorms are expected with the front and winds will be out of
the northwest from 5-10 kts the remainder of the night. There is a
chance (20-30%) of light showers and sprinkles that may impact the
Missouri Valley from 07Z-13Z associated with a mid-level front.
There is a slight chance(< 20%) for a thunderstorm near the Mo
River. Even if rain does occur, very dry air below 10000 ft will
mean no impact of visibility and ceilings are expected to remain
above 8000 ft.
Any remaining mid and high clouds will clear by early afternoon
leaving VFR conditions through 06Z Tuesday. Northwest winds from
late Monday morning through sunset will gust from 20-30 kts with
the strongest winds in east central South Dakota including KHON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...Dux
LONG TERM...Dux
AVIATION...Schumacher