775
FXUS63 KIND 281645
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1145 AM EST Fri Feb 28 2025

.KEY MESSAGES...

- Windy conditions with frequent gusts of 40-50 MPH are likely.
  Locally higher gusts will be possible

- A brief weekend cooldown temps in the 30s for highs.

- Potential for locally heavy rainfall and possible strong
thunderstorms Tuesday into Tuesday night

&&

.FORECAST UPDATE...
Issued at 950 AM EST Fri Feb 28 2025

Sunny start to the morning with temperatures and winds already
ramping up quickly. Peak gusts already are exceeding 20mph in some
locations as of 1430Z with temps rising through the 40s.

The primary focus for the update remains on the strong winds
expected for the rest of the day. A low level jet will swing through
the region into the afternoon ahead of a cold front set to pass
through this evening. Model soundings continue to advertise a well
mixed boundary layer by the afternoon with the potential for the top
of the mixing layer to approach the 700mb level. With 50+kt winds at
850mb by the afternoon...will have no issue bringing most of these
winds to the surface. Peak gusts at 45-50mph are likely this
afternoon focused especially along and north of I-70. Will continue
with the Wind Advisory for the entire forecast area. Skies will be
mostly sunny for much of the day but could see a brief increase in
clouds late day accompanying the cold front.

Considering the strong warm advection and mixed boundary layer ahead
of the frontal boundary...there is potential for temperatures to
overachieve this afternoon. Nudged up highs accordingly into the low
and mid 60s.

Zone and grid updates out.

&&

.SHORT TERM (Today and tonight)...
Issued at 246 AM EST Fri Feb 28 2025

Early this morning satellite imagery indicates high based cirrus
floating southeast in advance of a shortwave presently positioned
over the Upper Midwest. Isallobaric pressure gradient is minimal at
the moment, with a light westerly flow around 5 to 10 kts decoupled
from the deep mixing that occurred Thur. Still enough friction in
the near surface environment to inhibit temps from freely
radiating, which is likely going to keep temps in the low 30s for
much of Central Indiana thru daybreak. Southern portions of the
forecast area are slightly warmer in the mid/upr 30s.

Main highlight of note for midday will be how deep we mix, and
progged wind gusts flirting with wind warning criteria. Lets get
into the details and explain the setup. Wicked mid-lvl pressure
gradient exists from the Ohio Valley north through the Great Lakes
region, well depicted from the 500-700mb layers amongst several
guidance members. The near surface shortwave vort is progged to
slide southeast from Upper Midwest this morning and flirt with the
perimeter of the Ohio Valley midday. This will likely provide
optimal conditions for deep mixing to yet again occur across
Central Indiana. Strong isallobaric pressure gradients will set
the tone, and quickly be realized with the deep mixing from a
relatively clean boundary layer from minimal clouds and moisture.
This will set the stage for a well mixed deep column and a potent
LLJ on the order of 50-60kts. While it does not appear we will
fully bring to the surface such high winds, expect some filtering
to occur and still allow for gusts well past 45mph with some less
frequent gusts to 50- 55mph. The frequency to reach warning
criteria does not appear to be favorable at this moment, so only
adjustments to the current headline will be to expand for the
remainder of the forecast area in the south neighboring WFO LMK.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 246 AM EST Fri Feb 28 2025

Saturday through Sunday...
Deep 500mb trough will continue to progressively pivot east through
the region. Broad surface ridge should remain the main influence and
provide abundant clear skies and benign weather for the Sat
timeframe. Trough axis should be just east of the region Sun, but
the high amplitude ridge along the interior west should maintain a
northwest flow in the mid-lvls and keep the cooler air flowing
across the Ohio Valley into Sun.

Previous extended discussion...Dry weather will continue through the
weekend early next week. Temperatures will begin to recover early
next week, rising back into the 50s by Tuesday and Wednesday, as the
surface high departs to the east and heights build ahead of a
strong, rapidly developing leeside low which will then lift into the
Great Lakes during this time frame.

Widespread showers are highly likely Tuesday into Wednesday with
strong and deep poleward moisture transport expected ahead of the
aforementioned low. A few thunderstorms are certainly on the table
as well. Locally heavy rain potential and possibly some return to
minor flooding will be possible threats, particularly south where
streamflows are still receding from recent lowland flooding.

We will have to keep an eye out for a conditional severe threat, but
given the current expected track of the low, a far more substantial
severe threat would likely be located more to our south. This is
well supported by both the CIPS analogs and experimental CSU machine
learning guidance, as well as the SPC long range outlook.

The passage of this strong low will likely bring another at least
brief cooldown toward late week and into the next weekend.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1144 AM EST Fri Feb 28 2025

Impacts:

- Wind gusts of 40-45 knts this afternoon.
- Wind gusts diminish to 30-35 knts this evening.
- Gusts end as winds become NW overnight.

Discussion:

VFR conditions to prevail through the TAF period, however that will
not be the main story of this TAF period. Deep low pressure in place
over the Great Lakes will result in a strong pressure gradient
across the TAF sites this afternoon and evening. A strong LLJ along
with favorable mixing expected today due to steep lapse rates will
allow strong gusts aloft associated with the LLJ to mix downward.
This will allow gusts of 40-45 knts this afternoon.

Winds will begin to diminish somewhat after heating ends this
evening and the strongest parts of the LLJ depart eastward. The
strong pressure gradient across the area will still result in less
gusty winds this evening.

Overnight winds will become northwesterly in the wake of a cold
front. Cold air advection will allow for some mid level clouds to
develop, but these will still be VFR.



...although SCT/BKN
mid-level decks will fall to low-VFR after 06Z tonight from north to
south.

Main concern today and this evening will be windy conditions ahead
of/amid a strong but dry cold frontal passage.  A low level jet and
impressive surface gradient associated with this system, coupled
with deep mixing...will provide windy conditions with gusts peaking
around 40KT this afternoon.  Southwesterly surface flow today will
veer late today/early this evening...to northwest by 05Z tonight.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM EST this evening for INZ021-028>031-
035>049-051>057-060>065-067>072.

&&

$$

UPDATE...Ryan
SHORT TERM...Beach
LONG TERM...Beach
AVIATION...Puma