205
FXUS63 KIND 212017
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
317 PM EST Fri Feb 21 2025

.KEY MESSAGES...

- A gradual warming trend through the weekend into early next week,
with highs back in the upper 40s to upper 50s for the first half of
the work week

- Breezy at times early next week

- A low chance for rain late Monday night with more substantial
chances mid week

&&

.SHORT TERM (This evening through Saturday)...
Issued at 314 PM EST Fri Feb 21 2025

The end of the extended Arctic blast is in sight! A slight
moderating trend has begun today and will continue over the next
several days as surface high pressure shifts to the east and low
level flow turns southwesterly.

Latest surface analysis and satellite imagery show mainly clear
skies across Indiana with high pressure centered over Southern
Illinois. GOES Day Cloud Phase Distinction RGB still shows a
widespread snow pack over nearly the entire Midwest and Ohio Valley.
Snow has a lower albedo than bare ground; therefore any location
that has snow on the ground will see a slower moderating trend.
Due to the increasing late February sun angle, snow melt will
continue during the day today despite temperatures only in the
20s... and further snowmelt will occur tomorrow as highs are
expecting to rise above freezing for the first time in a week.
Snowpack should be completely melted by later this weekend, having
no impact on temperatures going forward.

Despite the dwindling snow pack, there should be enough snow on the
ground to influence lows tonight. Surface high pressure slowly
slides by overnight resulting in optimal conditions for radiational
cooling. This set up plus the snowpack should lead to temperatures
plummeting after sunset into the teens and single digits. Mid to
high clouds may move in overhead towards sunrise and during the
morning hours tomorrow, holding lows steady in the upper single
digits to low teens. However, would not be surprised to see typical
cold spots in low lying, wind sheltered areas to drop closer to
zero, specifically in the Wabash River Valley.

Tomorrow...

High pressure and low level ridging shift eastward on Saturday with
flow becoming southwesterly to westerly...working to further erode
the arctic airmass in place. Clearing skies, sunshine and better
surface heating will lead to more efficient mixing tomorrow into a
25 kt low level jet resulting in winds 10-15 mph and gusts to 20 mph
at times. Mixing and slight "warm" air advection will work to get
highs above freezing for the first time in about a week, with mid
30s possible along and south of I-70 and areas where snowpack
completely melts.

&&

.LONG TERM (Saturday night through Friday)...
Issued at 314 PM EST Fri Feb 21 2025

The long term period looks to be largely dry, aside from a couple
chances of rain next week, and much warmer than the past few days.
Through midweek there will be a warming trend, followed by a slight
cooldown.

Central Indiana will sit on the peripheral backside of a surface
high pressure system which will help to both keep any
precipitation suppressed and advect in warmer air to the region
from the SW. Highs for the first half of the week will be in the
50s with lows in the 30s. A passing upper wave late Monday night
to Tuesday morning could bring a small chance of rain across the
north, but for now the models are showing the much of the moisture
should stay closer to the low situated over the upper Great Lakes
and model soundings suggest a dry low to mid layer that could
prove to be too much to overcome for precipitation to hit the
ground. Due to uncertainties, have kept the low PoPs given by
guidance.

Breezy afternoons are also expected for the first half of the new
work week as a deepening PBL taps into moderate flow aloft and
promotes gustiness. Gusts as high as 20 to 25 mph look likely.

There is another chance of rain mid to late week as another upper
short wave moves through the region, but timing of this event is
less certain as there lacks agreement between models for now. Once
this system passes cooler air will move back in, bringing closer to
normal temperatures to end the week. Beyond the 7 day forecast there
are signals for another blast of cold air as we enter March so will
continue to monitor this as it gets closer.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1225 PM EST Fri Feb 21 2025

Impacts:

- None

Discussion:

High pressure will be the dominant weather influence across Indiana
over the next 24 hours with mainly VFR expected.

Surface high pressure slides over the region tonight before shifting
eastward tomorrow. Subsidence under the high and dry air will lead
to mainly clear skies other than a few high clouds passing by during
the morning hours tomorrow. Southwest winds will remain under 10 kts
this afternoon at all TAF sites then drop to near calm during the
overnight hours. A tightening pressure gradient tomorrow afternoon
in addition to boundary layer mixing may result in sustained winds
08-13 kts with gusts to 18 kts at times. No cig or vis issues
expected during the period.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...CM
LONG TERM...KF
AVIATION...CM