971
FXUS63 KLSX 211906
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
106 PM CST Fri Feb 21 2025

.KEY MESSAGES...

- Steady warming will continue through Monday, with temperatures
  climbing back above normal tomorrow, and into the 50s by Monday.

- Precipitation chances will be minimal until mid-week, with a
  modest chance (20-40%) for showers Wednesday and Thursday.

&&

.SHORT TERM...  (Through Late Saturday Night)
Issued at 104 PM CST Fri Feb 21 2025

After one last very cold morning throughout the area, particularly
in the Ozark valleys where morning lows dropped to nearly -10
degrees, our much anticipated steady warming trend is off to the
races. This will be gradual at first, starting with this afternoon
when temperatures will likely only climb into the mid to upper 20s
over the remainder of this afternoon, but between the calm winds and
full sun, the improvement will be noticeable even if we remain
almost 20 degrees below seasonal averages.

Overnight tonight, a weakening shortwave is expected to move through
the area, roughly paralleling I-70. This feature is currently
located across western Kansas and has managed to produce some light
snow well to our west, but as this feature arrives locally
precipitation is no longer expected to reach the surface. Instead,
mid-level cloud cover and virga is about all that this system is
expected to muster, which will largely occur during the overnight
hours. Meanwhile, temperatures are likely to be quite cold, but not
nearly as cold as it was this morning as we will likely settle
somewhere in the teens area-wide.

By tomorrow, southwesterly low level flow will become more firmly
established as surface high pressure moves off to the east.
Meanwhile, geopotential heights will also build as a broad ridge
becomes established across the Plains and intermountain west, and
the end result will be another 10+ degrees of warming tomorrow
afternoon. Expect highs to reach above freezing for the first time
in several days, although it will still be a struggle for
anywhere to climb above 40 degrees. This is still about 10 degrees
below average, but rest assured we will continue to warm through
the weekend and into early next week. Meanwhile, plenty of sun can
also be expected, and this will eat up quite a bit of the
remaining snow cover.

BRC

&&

.LONG TERM...  (Sunday through Next Friday)
Issued at 104 PM CST Fri Feb 21 2025

Between Sunday and Monday, confidence remains very high that
temperatures will continue to warm at a steady pace thanks to the
gradually building ridge and persistent southwesterly low level
flow. Ensemble guidance has consistently indicated that temperatures
will warm by 10-12 degrees each day during this period, with very
narrow spreads (interquartile ranges of 3 degrees or less). This has
been the case for several days now, and there is little evidence to
suggest that this will not occur aside from a few sporadic outliers.
As such, expect us to return to near average temperatures by Sunday,
to around 10 degrees above average (mid to upper 50s) by Monday.

Meanwhile, we will remain in a west-northwest upper flow regime,
which will allow a series of fast-moving shortwaves to move through
the upper Mississippi Valley and Great Lakes from early to mid-week.
The first of these systems are expected to be very weak and mostly
displaced to the northwest, but one of these systems is likely to
slow down our warming trend by sending a weak cold front into the
area Tuesday. This will be followed by slightly stronger shortwave
may move through our area between Wednesday and Thursday, which has
consistently been depicted as the next best opportunity for
measurable precipitation over the next 7 days. Even so, this is far
from a sure thing as there has been a very slight weakening trend in
recent ensemble guidance, with precipitation probabilities remaining
at only around 20 to 40% during this period. Meanwhile,
instability projections remain very low, and the potential for
significant/impactful precipitation or thunderstorms appears
relatively low as a result. It also appears that temperatures are
very likely to remain warm enough to produce primarily liquid
rain.

Otherwise, the primary impact of this system will be to put the
brakes on our warming trend, and perhaps even cool us off slightly
as another cold front moves through the area. Still near to slightly
above average temperatures continue to be favored from mid to late
week.

BRC

&&

.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1039 AM CST Fri Feb 21 2025

VFR conditions and light winds are expected throughout the 18Z TAF
period. Increasing mid-level cloud cover and virga are expected
overnight, but precipitation is not likely to reach the surface.
Otherwise, no weather hazards are expected.

BRC

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX