000
FXUS63 KIND 261651
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1251 PM EDT Fri Apr 26 2024

.KEY MESSAGES...

- Becoming Cloudy with rain chances this afternoon and evening;
Warmer.

- Clouds with rain chances tonight.

- Above normal temperatures and numerous chances for showers and
thunderstorms expected through the long term.

&&

.FORECAST UPDATE...
Issued at 945 AM EDT Fri Apr 26 2024

Hi-Res soundings and obs are showing a dry boundary layer over
central Indiana this morning with high pressure over the eastern
states and a low pressure system over the Plains. Meanwhile, an
upper ridge was overhead. Visible satellite was showing increasing
mid and high clouds, while radar was showing showers dissipate as
they move northeast into southwestern Indiana. Nonetheless, with
isentropic lift ramping up and some moistening from the top down,
will keep chance PoPs going this afternoon.

Despite the increasing cloud cover, warm advection with breezy
southeast winds should allow temperatures to climb all the way to
the middle and upper 60s.

&&

.SHORT TERM (Today and tonight)...
Issued at 312 AM EDT Fri Apr 26 2024

Synopsis:

Surface analysis early this morning shows strong high pressure in
place over Upstate NY and New England. Deep low pressure was found
across western Kansas. This pattern was resulting in dry easterly
surface flow across Central Indiana and dew point temperatures were
in the dry 30s. GOES16 shows the arrival of high cloud pushing into
Central Indiana from the middle Mississippi Valley. Water vapor
shows  ridging in place over the Plains aloft, with a plume of
tropical moisture streaming into the Mississippi Valley. Radar shows
some light showers across eastern MO, southern IL and far western
KY. These showers were making better progress southeast than
northeast due to the flow aloft.

Today...

Models suggests the ridge axis aloft found to the west will advance
east, pushing across Indiana to Ohio and the eastern Great Lakes
tonight. This will allow for the development of southerly flow aloft
and the advancement of the previously mentioned tropical moisture
plume over Central Indiana.  Meanwhile at the surface, the low
pressure system over KS will advance northeast, making slow progress
due to the strong blocking high. However the GFS 300K isentropic
surface shows strong up glide arriving this afternoon with specific
humidities over 8 g/kg. Lower level flow remaining dry and from the
east will hamper the development of precipitation this afternoon.
HRRR shows very scattered shower development as the forcing arrives
this afternoon and persists into the evening. Models are a bit
different on the strength and organization of the upper forcing, but
are more in agreement with the isentropic lift arriving as the ridge
axis exits east and southwest flow develops. Thus given these
features will include a dry morning forecast, and begin to ramp up
to chc pops only this afternoon and early evening. Confidence
remains low on specific timing and location due to the moisture
needing to overcome the dry easterly surface flow. Given the
development of southwest flow and warm air advection today, will
trend highs into the middle 60s.

Tonight...

Little overall change is expected in the weather pattern tonight.
The surface low over NB is expected to trek northeast toward the
western Great Lakes, while the strong area of surface high pressure
over the east coast blocks its progress eastward. This continues to
result in southerly flow across Central Indiana overnight. The
strong upper ridge previously mentioned also remains over the east
coast, keeping southwest flow aloft over Central Indiana. Models do
trend toward a windy night as a moderate pressure gradient remains
in place across Central Indiana along with a 50 knt LLJ over IL and
and Indiana within the warm sector ahead of the low to the
northeast. Isentropic lift and warm air advection remain in place
overnight as this much more humid air mass arrives. Overnight,
forecast soundings trend toward saturation with pwats over 1.3
inches. Thus will use at least likely pops given these features,
however again precip may be more scattered than constant. Given the
continued warm air advection, will trend overnight lows toward
around 60.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 312 AM EDT Fri Apr 26 2024

The long term period will be one of above normal temperatures and an
active pattern for showers and thunderstorms. Highs will range from
the low 70s up to the mid 80s, with Sunday being the warmest day
during the timeframe as the region sits under strong southerly to
southwesterly flow for most of the time.

Multiple waves will be moving through a larger troughing pattern
that will remain fairly stagnant through at least midweek. The first
system will be on its way out Saturday as slight chance PoPs start
out the day but will diminish by the end of the day. The next wave
will bring additional rain from Sunday night through around midweek.
By midweek the upper pattern becomes noisier in the models but seems
to take on more of a zonal pattern with additional waves that may
still impact the region from midweek into the end of the week. At
this time confidence is lower for the end of the period as far as
PoPs go.

Luckily, at least through early next week, stronger to potentially
severe storms look to remain to the west and southwest of Indiana,
where the best instability will be. By Monday or Tuesday, better
convection potential could reach central Indiana, leaving a non-zero
severe threat but this should become clearer in the coming days.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1251 PM EDT Fri Apr 26 2024

Impacts:

- MVFR and possibly briefly worse flying conditions are possible
  in convection after 09z

- Non-convective low level wind shear from 06z-13z

- Winds 150-190 degrees with gusts to 25 knots or more after 06z

- Lightning possible mainly Saturday afternoon

Discussion:

GOES16 visible loop is showing a few holes in the overcast.
Otherwise, look for mostly broken to overcast VFR flying conditions
with a shower or two possible through this evening. More showers are
also possible overnight and into Saturday with MVFR or briefly worse
flying conditions at times.

Breezy conditions and non-convective low level wind shear are
expected overnight into Saturday as a low level jet moves across
the area.

&&

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

$$

UPDATE...MK
SHORT TERM...Puma
LONG TERM...KF
AVIATION...MK