Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 252307
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
707 PM EDT Sat Jun 25 2022

...Updated Aviation Discussion...

.Short Term...(This evening through Sunday night)
Issued at 257 PM EDT Sat Jun 25 2022

Highlights:

* Increasing cloud cover from the NW this afternoon. Highs in the
  mid 80s to the NW and low 90s to the S.

* Frontal passage beginning late tonight, continuing through
  tomorrow afternoon will provide chances for rain and
  thunderstorms.

* Thunderstorms are expected to remain unorganized and sub-severe,
  although a few could become severe tomorrow afternoon over SE
  central Indiana.

Rest of Today and Tonight...

Central Indiana remains below anomalous mid level heights, keeping
most of the central Indiana within a surface moisture minimum versus
outlying regions. Elsewhere, a decaying MCS is approaching from the
west, infiltrating the dry air resulting in light rain/sprinkles and
virga. This MCS will slowly saturate the near surface over NW/N
central Indiana, but most locations` dew points should remain in the
upper 50s to low 60s. Afternoon highs will vary across the state dew
to the discontinuous cloud cover. To the NW, temperatures should
stay in the mid 80s with influence from marginal evaporative cooling
and overcast conditions. To the S, less cloud cover and drier
surface layer will aid in warming, resulting in highs in the low
90s.

A few locations in far NW/N central Indiana may see minimal QPF as
the MCS decays within dry air. By this evening, any precip should be
off to the N as central IN waits for the second round of
thunderstorms to propagate along an advancing cold front.

As mentioned, convection is expected to initiate along the frontal
boundary over IL later this evening, advancing E/SE along a
developing cold pool. By the time this MCS reaches central Indiana
late tonight, any ongoing convection should be displaced from the
instability as the cold pool surges forward. This should result in
weak broken showers and isolated thunderstorms over W, NW and N
central Indiana through the late night and early morning hours.
Coverage of showers should diminish as the line advances into the
drier air over SE central Indiana.

Overnight lows will be fairly high given the lack of diurnal cooling
beneath a deep overcast layer. Current expectations are for lows in
the low 70s over most of central Indiana.

Tomorrow and Tomorrow Night...

The aforementioned MCS will continue to decay tomorrow morning
through parts of E/SE central Indiana, becoming a non-precipitating
overcast layer by the late morning hours. Moisture will increase
from both the NW and S, eventually overcoming the subsidence induced
dry layer. This will increase instability within the warm sector, of
which should be over S/SE central Indiana tomorrow afternoon.

CAMs still have varying solutions on frontal progression behind the
previous night`s MCS, therefor increasing the uncertainty on where
CI will occur tomorrow. There has been a slight slowing trend over
the last few model cycles, leading to an increased belief the front
will still be over central Indiana tomorrow afternoon. Current
thoughts are the boundary will be somewhere near the Bedford,
Columbus, New Castle corridor by the time convective temperatures
are reached in the afternoon.

Residual mid level clouds during peak diurnal warming will weaken
near surface lapse rates; still significant cool air aloft should
lead to SBCAPE above 1500 J/kg. Shear will be weak throughout
tomorrow with no upper level jet and the low level jet present until
late in the evening. Therefor, any organized convection will likely
be along cold pools, of which will be the primary concern for
damaging wind gusts. A mid level dry layer could also increase
chances for cold pools to develop, but the threat for severe winds
should remain isolated until the LLJ jet increases in the evening
over Ohio.

By tomorrow night, the front will be east of central Indiana, with
no precipitation expected behind the boundary. Temperatures should
decreases behind the front within modest CAA. Expect lows near 60
with mostly clear skies.

&&

.Long Term...(Monday through Saturday)
Issued at 257 PM EDT Sat Jun 25 2022

- Dry much of the week ahead
- Best chances for rain on Saturday

Monday through Friday...

Models suggest northwest flow in place aloft on Monday. This flow is
expected to gradually shift to a more zonal flow by Friday, with the
strongest flow found across the northern plains toward the Great
Lakes, well north of Indiana. This flow should steer any forcing
dynamics well north of Central Indiana. Meanwhile to the south, a
strong, broad and large area of high pressure aloft is expected to
persist across the southern United States. Models continue to show
subsidence across Central Indiana in the wake of Sunday’s front as
surface high pressure moves through the area.  This is expected to
persist through at least mid week, leading to mostly sunny days and
mostly clear nights. The surface high pressure is shown to reach the
east coast by Thursday and Friday. This will allow for a gradual
warming of temperatures as the week progresses and southerly surface
flow develops on Thursday and Friday and gulf moisture will be able
to return. Thus will continue a dry forecast for much of the week.

Saturday...

Best chances for rain are expected on Saturday as a lingering tail
of a frontal boundary is expected to arrive and stall across Central
Indiana. With a few days of warm and moist gulf flow in place ahead
of this system plentiful moisture will be available for precip. Best
forcing dynamics appear to remain well north of Central Indiana,
across the Great Lakes. However broad cyclonic flow aloft is shown
to set up over Ontario and Quebec with embedded waves passing. This
flow, albeit well north of Central Indiana, may slightly influence
and help trigger precipitation along with the stalled frontal
boundary. Thus will include pops for Saturday, but confidence is low
given this is day 7.

&&

.Aviation...(00Z TAF Issuance)
Issued at 706 PM EDT Sat Jun 25 2022

IMPACTS:

- Mainly VFR Conditions through 11z. Then, MVFR ceilings.

- Convection possible after 05z and before 18z Sunday

- Winds 160-190 degrees less than 10 knots will veer to 210-240
degrees after 05z and 260-300 degrees after 11z-13z as a cold front
moves through.

Discussion:

A cold front will drop southeast across the terminals Sunday morning.
Deepening moisture and increased instability along with lift from
the approaching front and trailing upper wave will trigger a
few showers and thunderstorms overnight and Sunday morning.
Flying conditions could briefly deteriorate to MVFR in convection
with more widespread MVFR ceilings Sunday.

South and southwest winds will switch to the west and northwest
on Sunday, in the wake of the cold front.

&&

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

$$

Short Term...Updike
Long Term...Puma
Aviation...MK


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