Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 300822

Area Forecast Discussion
National Weather Service Indianapolis IN
422 AM EDT Thu Mar 30 2017

The AVIATION section has been updated below.


Issued at 232 AM EDT Thu Mar 30 2017

A powerful low pressure system over the Central Plains states will
push a warm front toward Indiana today...pushing showers across
Indiana today. Another round of Thunderstorms will be possible
late this afternoon and evening as the Low pressure system pushes
even closer to Indiana.

A rainy and cooler day is in store on Friday as the low pushes
across Indiana. Dry weather will return on Friday Night and into
the weekend as high pressure builds across Indiana for the

More active and wet weather is expected next work week as more low
pressure systems are expected to push through the region.


.NEAR TERM /Today/...

Issued at 232 AM EDT Thu Mar 30 2017

Active Weather day ahead.

Surface analysis early this morning shows a deep low pressure
system over eastern Kansas. A warm front extended southeast from
the low across Missouri to Southern Illinois and Western Kentucky.
Water vapor imagery shows a deep cyclone in place with a conveyor
belt of warm and moist air streaming northward through Mississippi
River Valley into central Indiana. Cool easterly flow was in place
at the surface across Central Indiana...associated with departing
high pressure to the northeast. This was resulting in a
overruning situation across Central Indiana.

Many ingredients favorable for rain today. Water vapor shows
plentiful moisture arriving today ahead of an approaching warm
front. Strong overrunning in place. Upper support is also
favorable as the models suggest the upper low to the west will
help provide dynamics. Time heights show a saturated column today
with good forcing. Thus will aim for 100 pops today. HRRR suggests
two possible wave today. The first arriving this morning as seen
on radar as showers over western Illinois begin to arrive in
Indiana. Models then suggest an upper wave arriving late this
afternoon and early this evening. Forecast soundings show decent
instability with CAPE near 1000 j/kg. Furthermore...good lower
level shear remains in place...amplifying the severe threat.
Confidence for severe is questionable. With rain expected part of
the day and better dynamics as set up farther south...not sure how
much moisture and heating may reach the area as areas across
Tennessee and Western Kentucky see better deep convection.
Nonetheless will include high pops and trend highs close to
forecast builder blend. Should clouds and rain linger though...we
will need to trend lower.


.SHORT TERM /Tonight through Saturday Night/...

Issued at 232 AM EDT Thu Mar 30 2017

GFS and NAM suggest strong forcing arriving this afternoon and
continuing in to the evening hours. Forecast soundings again
suggest a couple periods of showers/storms in the period...showing
deep saturation. Convection from the afternoon will likely bleed
into the evening hours and will need to carry high pops again.
Again, excellent shear in place along with possible instability
suggest severe weather is possible. After the severe threat
ends...forecast soundings again show good lower and middle level the large and broad low pressure system arrives in
the area. Thus again. HIgh pops tonight and will trend lows above

Surface low arrives for Friday. At that point the severe threat
will be lost as instability is gone...but clouds and lower level
moisture will remain in the area as forecast soundings and time
heights show lower level saturation. Will trend pops higher on
Friday than mavmos given light precip that will be expected as the
upper low passes. Will also trend high at or below a forecast
builder blend given the expected clouds and light precip.

Dry weather expected to return for Friday through Saturday night.
Models suggest the low will depart to the east allowing another
Cool canadian high pressure system to build across the region from
the NW. Forecast soundings show mainly a dry column associated
with subsidence...but some lingering lower level moisture. Thus
partly cloudy will work here. Will stick close to the forecast
builder blend here on temps.


.LONG TERM /Sunday Through Wednesday/...
Issued at 249 AM EDT Thu Mar 30 2017

Models are close enough that the model blend initialization
was accepted for most items.

Like a stuck record, a series of low pressure systems will continue
to bring rain chances to much of the Long Term. Of course models
still have a good amount of variability between them, so confidence
remains low in timing of highest PoPs through the period. Thus
decided to just stick with the blend.

Temperatures look to remain above average through the period.


.AVIATION /Discussion for the 300900Z TAF Update/...
Issued at 422 AM EDT Thu Mar 30 2017

A thunderstorm is moving away from KIND now, so left just VCSH
mention since thunder is isolated. Adjusted timing of tempo group
based on latest hi-res model data.

Previous discussion follows...

VFR conditions will be likely much of the night. MVFR conditions may
overspread LAF and briefly IND/HUF tomorrow as a low pressure system
moves into the area.

Showers and a few thunderstorms will approach the area late tonight,
but uncertainty will preclude much more than a TEMPO mention and/or
VCTS mention.

Winds will be easterly early in the period, generally around
10-15KT. Occasional gusts may occur but will be too infrequent for
prevailing inclusion. Winds will become more southerly with time
as the low approaches.

Visibilities may be reduced at times in showers mainly tomorrow.
Fluctuations will be likely as is often the case.




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