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000
FXUS63 KIND 221241
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
841 AM EDT Mon Apr 22 2024

.KEY MESSAGES...

- Morning sunshine with high clouds arriving later today; Warmer

- Increasing rain chances Tuesday with low chance for
  thunderstorms, temperatures near or below normal through Thursday

- Active pattern likely to return late this week into the weekend
  with above normal temperatures

&&

.FORECAST UPDATE...
Issued at 840 AM EDT Mon Apr 22 2024

Surface analysis late this morning shows strong high pressure in
place over eastern TX and eastern OK. A strong surface ridge
extended northeast from the high, into the Ohio Valley. GOES16 shows
clear skies across Indiana as temperatures were climbing out of the
30s. Aloft, ridging was found over the plains stretching northeast
to the Great Lakes. some high CI was found on the backside of the
ridge over MN and IA.

This afternoon the surface high pressure system is expected to drift
east, but still maintain control of the weather across Central
Indiana. Forecast soundings show a dry column this morning, but hint
toward some upper level saturation by late afternoon. This is
indicative of the high CI arriving across Indiana from the
northwest. Thus the ongoing forecast for mostly sunny skies this
morning with increasing clouds this afternoon remains on track.

Weak warm air advection will be in place this afternoon along with
good mixing and heating expected. Ongoing high temperatures in the
lower to middle 60s appear on target.

&&

.SHORT TERM (Today and tonight)...
Issued at 301 AM EDT Mon Apr 22 2024

Clear conditions with surface MSLP high position resulting in
light/calm winds has resulted in low to mid 30s for temperatures
this morning, and areas of frost. A quick warm-up will occur shortly
after sunrise.

Shortwave ridge axis will cross the state this afternoon and low/mid-
level tropospheric flow will trend southwesterly. Warmer plume
advecting in aloft coupled with 1.5-km mixing depths will result in
warmer 2-m temperatures. With this pattern change, we will pivot to
the 75th percentile and statistical guidance blend for temperatures.
This places near mid-late April climatology (mid-60s for maximum
temperatures).

Wind speeds and gusts will be highest during peak mixing mid-late
afternoon, but generally still be light with gusts generally under
20 mph.

Cirrus will increase today preceding the next upstream wave and its
high-level Pacific moisture connection. Much warmer conditions are
expected tonight due to the warm advection pattern and midlevel
clouds, so no frost is expected.

&&

.LONG TERM (Tuesday through Sunday)...
Issued at 301 AM EDT Mon Apr 22 2024

.Tuesday...

Next chance for rainfall arrives Tuesday as a cold front pushes into
the region from the north. Increasing large scale ascent and warm
air advection combined with a relatively narrow corridor of
sufficient moisture supports widespread precipitation along the
front Tuesday afternoon and evening. Subsidence induced dry air
across the mid south will limit overall moisture advection northward
into the Ohio Valley with deeper subtropical moisture and high dew
points remaining further south. With this in mind, QPF amounts
should generally be around or less than half an inch. Due to lower
dew points and weaker lapse rates through the column, instability
looks marginal at best for thunder potential.

Highs are expected to range from the mid 50s to mid 60s. A
progressive pattern aloft should help push the aforementioned system
further east overnight allowing drier conditions to return.

.Wednesday through Thursday...

Cold air advection and surface high pressure building into the Great
Lakes behind the departing low will result in a brief period of
cooler conditions and below normal temperatures Thursday. Highs in
the mid 50s to low 60s are expected for Wednesday. Still watching
Late Wednesday night into Thursday morning for the potential for
patchy frost in portions of Eastern and North Central Indiana. High
pressure will be centered over NY state during this time frame with
light easterly winds and mainly clear skies across Indiana. More
optimal conditions for frost formation will be further north and
east of Indiana where winds will likely go calm; however low lying
wind sheltered areas in North Central and Eastern Indiana could dip
down into the low to mid 30s.

.Friday into Next Weekend...

Another pattern shift is expected to take place late in the week
with a much warmer and wetter weather pattern setting up for Late
April into early May. Mid to long range guidance has been consistent
in showing an active storm track setting up in the Plains beginning
Friday. Ridging builds over the Midwest with a southwest flow
pattern over the Plains. Numerous strong lows and associated fronts
are expected to push northeast from the Plains and into the Great
Lakes region during this timeframe resulting in multiple chances for
shower and thunderstorms. Warm front pushes northward through
Indiana Friday afternoon and evening bringing the first chance for
showers and storms. Model disagreement increases into the weekend.
While confidence is lower on exact details of timing of storms,
exact track of lows and fronts, confidence is high in a wetter and
warmer pattern continuing through the weekend and into the next
week.

A low end threat for strong to severe storms cannot be ruled out
heading into the weekend as increasing instability and mid-upper
level flow from approaching disturbances could support organized
convection. However, confidence is low due to the disagreement
between guidance. CSU machine learning currently shows low
probabilities for severe weather over central Indiana during this
period. The better setup for severe weather looks to be further west
where better instability, and deep layer shear is likely.

One thing to note, Indianapolis is already in the top 13 for wettest
April`s on record. Numerous chances for rainfall Tuesday, and then
again late next week into the weekend will likely push Indianapolis
at least into the top 10 for wettest April`s on record.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 605 AM EDT Mon Apr 22 2024

Impacts:

- Gusts up to around 15-17 knots this afternoon into the night

Discussion:

Southwesterly winds will gust during peak mixing and MSLP gradient
will continue to result in wind speeds and gusts staying up through
the night. Cirrus and mid clouds will move in today but VFR
conditions will prevail.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 10 AM EDT this morning for INZ021-028>031-
035>049-051>057-060>065-067>072.

&&

$$

UPDATE...Puma
SHORT TERM...BRB
LONG TERM...CM
AVIATION...BRB