Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 221747

Area Forecast Discussion
National Weather Service Indianapolis IN
147 PM EDT Sun Apr 22 2018

The LONG TERM Section has been updated below.


Issued at 342 AM EDT Sun Apr 22 2018

More clouds are in store for central Indiana for the next few days
along with increasing chances for showers as low pressure moves from
the plains through the Tennessee and Ohio valleys. A couple of upper
waves and associated frontal systems will move through the area late
in the week to bring more chances for rain to the area.


.NEAR TERM /Rest of Today/...
Issued at 942 AM EDT Sun Apr 22 2018

Mid level cloud cover was draped across the region this morning as
low pressure and an associated inverted surface trough lifted
north through the lower Mississippi Valley. Light rain showers
were drifting north across the lower Ohio Valley and through
southern Illinois...but the lingering dry airmass over central
Indiana was keeping showers out of the forecast area. 1330Z
temperatures ranged from the mid 40s north to the mid 50s south.

Overall forecast in great shape with only minor adjustments needed
for the morning update. The surface low will continue to lift
north through the day and should be located over west Tennessee by
evening. Waves of rain showers will progress north into the lower
Ohio Valley ahead of the low...but the dry airmass present over
the region in the lowest 10kft will continue to keep a lid on rain
making much inroads into the forecast area through this evening.
Low pops remain warranted across the lower Wabash Valley by late
afternoon as moisture slowly advects into the region...but do not
anticipate more substantial showers across the region until later
tonight as the surface wave approaches the region from the

Despite a substantial amount of mid level clouds which will limit
sunshine today...warm advection will enable temperatures to warm
into the 60s across the forecast area. Expecting highs generally
about 5 degrees warmer than Friday and Saturday and the current
forecast has this thinking handled well.

Zone and grid updates out.


.SHORT TERM /Tonight through Tuesday night/...
Issued at 342 AM EDT Sun Apr 22 2018

An upper low and surface low are progged to stack over western
Tennessee tonight and then slowly make their way northeastward
through Kentucky and off to West Virginia during the short term.
This will bring increasing chances for rain showers, with the
highest chances on Monday in the area of best forcing northeast of
the low. Probabilities will remain high in the eastern counties into
Tuesday as the low gets east of the area. With the upper low to the
south and cloudy skies high temperatures will be a bit depressed on
Monday and Tuesday, hanging around in the upper 50s to lower 60s.
Highest rainfall amounts should be in the southern/southeastern
counties during the short term, but even those should only be around
half an inch. Continuing to keep thunder out of the forecast during
this period due to lack of instability and paltry lapse rates.


.LONG TERM /Wednesday Night through Sunday/...
Issued at 147 PM EDT Sun Apr 22 2018

Much of the extended period now appears likely to be dry with one
major exception Thursday night and Friday as a sharp upper trough
and associated surface cold front dive across the area.

High pressure will build in behind the early week system with the
upper level wave originally expected to impact the region midweek
now likely to remain off to the south and west of central Indiana.
The aforementioned upper trough will dive through the parent eastern
U S trough and across the region Thursday night and Friday bringing
scattered showers and making Friday the coolest day of the extended
as the region is impacted by raw and chilly northwest winds.

Once this feature shifts off to the east Friday night...a transition
to dry and progressively warmer weather is expected for next weekend
as surface high pressure builds in and the broad eastern upper
trough moves away. Temperatures will be cooler than normal initially
in the 50s and lower 60s...with the potential for mainly 50s if not
slightly chillier on Friday. The weekend will see a nice recovery as
mid level heights rise and warm advection develops. Should see highs
approaching 70 by Sunday with even warmer temperatures on the
horizon heading into the first few days of May.


.AVIATION /Discussion for 221800Z TAF Issuance/...
Issued at 1230 PM EDT Sun Apr 22 2018

VFR conditions will continue into Monday morning...with
restrictions developing within showers towards the end of the
forecast period.

An upper level low and an attendant surface wave will lift into
the lower Ohio Valley through Monday...with showers becoming
likely across central Indiana on Monday morning. The presence of
high pressure to the northeast of the region will maintain a dry
easterly flow into the region through much of tonight...keeping
the lowest 10kft dry and limiting northward extent of the rain
from the south.

Expect mid level ceilings to persist into the overnight before
more substantial moisture advection develops towards daybreak
Monday. Model soundings and RH progs show deeper moisture
infiltrating the boundary layer Monday morning with MVFR stratus
and possibly lower developing within showers. Surface flow will
remain easterly.





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