000
FXUS63 KIND 141042
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
642 AM EDT Sun Apr 14 2024

.KEY MESSAGES...

- Breezy and warm today
- Isolated thunderstorms possible far east, mainly this evening
- Ongoing River Flooding
- Multiple rounds of showers and storms this week, severe weather
  possible Tuesday and Wednesday
- Cooling trend late next week.

&&

.SHORT TERM (Today and tonight)...
Issued at 300 AM EDT Sun Apr 14 2024

This Morning...

Some weak upper energy moving through northwest flow aloft is
bringing an increase in some high clouds early this morning. As this
moves through, high (and some mid level) clouds will accompany it.
Will make skies partly cloudy early this morning.

Later during the morning, some high clouds from remnants of upstream
convection well to the northwest may move across northern portions
of the area, while southern portions see few clouds.

A low level jet will be on its way out of the area after sunrise,
but enough will linger so that mixing brings down some wind gusts up
to around 30 mph.

This Afternoon...

Models have slowed the progression of a cold front that will move
into northern central Indiana late in the day. This will be the only
source of forcing as there is no upper support. Dewpoints will have
risen into the mid and upper 50s, so there will be some moisture
around for instability to build.

However, given the slower speed of the front and no support with it,
will only go with slight chance PoPs in the far northeast very late
in the period.

Blended temperature guidance looks too cool given sunshine and
southwest flow. Will bump up some so that highs will be around 80
degrees.

Tonight...

The cold front will slowly sink south across the area. Again, there
will be no upper support for the the front. Instability will be
around at the start of the period, but this will diminish after
sunset as heating is lost. Thus, confidence for any convection
remains low.

Will go with some slight chance PoPs in the far east this evening
(closer to the parent surface low pressure), then dry overnight.

The better cold air behind the front will remain north of the area,
so lows in the 50s still look reasonable.

&&

.LONG TERM (Monday through Saturday)...
Issued at 300 AM EDT Sun Apr 14 2024

Upper-level ridging builds across the central CONUS this weekend,
allowing for the warming trend to continue. Meanwhile, a semi-cut
off upper low over California will slowly progress eastward. This
low should reach Indiana by Tuesday/early Wednesday bringing active
weather back to the region.

Monday

A weak cold front looks to across Indiana from north to south late
this evening and overnight. The front should settle across southern
portions of the CWA by Monday morning. Surface temperatures do not
appear to be dramatically different on either side of the boundary,
but dew points should be. Readings in the 40s across northern
Indiana will contrast with values in the 60s in southern portions of
the state. This front may also act as a catalyst for isolated
showers and thunderstorms Monday afternoon/evening. Though large-
scale forcing associated with a shortwave exits the region earlier
in the day, enough buoyancy may be present to allow for some
diurnally-driven convection.

Model soundings show weak low-level flow, and relatively dry mid-
levels. Steep lapse rates (7-8 C/km) with rather deep CAPE profiles
are also apparent. Hodographs are generally long and straight with a
mean shear vector out of the northwest. Based on this, primary
convective hazards are large hail and strong wind gusts. The overall
threat for severe weather is quite low, however, due to limited
convective coverage. Additionally, the front may end up south of our
CWA confining the threat to southern Indiana.

Tuesday/Wednesday

The next threat for strong/severe thunderstorms begins on Tuesday as
the western trough edges eastward. Guidance is tightly clustered
through Tuesday, with any significant variation relegated to the
mesoscale. As the system ejects into the Plains on Monday, it
quickly induces cyclogenesis in the lee of Rockies. The resulting
surface low strengthens and moves northeastward, quickly occluding.
By the time it reaches Indiana, it will be occluded with the parent
trough de-amplifying. Though the system will be in a weakening state,
it should still posses sufficient forcing and shear for organized
convection. Convection may occur in two rounds, with round one
occurring Tuesday evening/night as activity outpaces the system`s
cold front. The second round possibly occurring Wednesday along the
cold front itself as it passes through.

Model soundings from within the system`s warm sector show ample
shear (50kt 0-6km) and steep lapse rates (around 7 C/km). Hodographs
show curvature below 1km, but are generally straight above that.
Some mid-level dry air is present, but not all models show this.
Based on these, it would appear that all convective hazards are on
the table. As of now, the greatest threat appears west of our CWA
across Illinois. Upscale growth is likely as activity progresses
into Indiana. Confidence is lower regarding the second round of
convection on Wednesday, as it may rely on the evolution of
Tuesday`s activity.

Thursday onward

Once Tuesday/Wednesday`s system passes through, a cooling trend is
expected to commence. Zonal flow aloft with northwesterly flow at
the surface should promote generally dry weather through the end of
the period. One exception may be early Friday as a weak wave aloft
zips through the flow. A reinforcing shot of cooler air is possible
following that system, and frost is not out of the question by the
weekend.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 641 AM EDT Sun Apr 14 2024

Impacts:

- Non-convective low level wind shear ending early
- Wind shift to north tonight

Discussion:

Low level wind shear will end not by 14Z as mixing commences.

VFR conditions are expected through the period. Some mid and high
clouds will move through during the first few hours of the period,
then cumulus will pop up in the afternoon. These will persist into
the evening hours. Any isolated convection this afternoon and
evening should remain east of the sites.

Winds will shift to the north and northwest tonight as a cold front
moves through.

&&

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

$$

SHORT TERM...50
LONG TERM...Eckhoff
AVIATION...50