Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 171038

Area Forecast Discussion
National Weather Service Indianapolis IN
638 AM EDT Sat Mar 17 2018

The NEAR TERM Section has been updated below.


Issued at 308 AM EDT Sat Mar 17 2018

A low pressure system, over northern Missouri, will slide southeast
across the Ohio Valley and Appalachians today. This system will
bring a swath of freezing rain to northeastern sections of central
Indiana this morning. The rest of the area will see rain. Southern
sections could even see a few morning thunderstorms. The rain will
be ending from northwest to southeast this afternoon as the system
moves out.

High pressure will bring a brief end to the precipitation tonight
through Sunday evening. Then, more rain will move in Sunday night
and Monday associated with a Rockies system. The rain will mix with
or change to snow Monday night into Tuesday. Finally, yet another
system will bring rain chances to the area late next week.

Monday and Tuesday will see temperatures rebound into the 50s.
Otherwise, below normal temperatures are on tap through next work


.NEAR TERM /Today/...
Issued at 638 AM EDT Sat Mar 17 2018

The road temperatures have stayed above freezing, and temperatures
will gradually warm this morning, so cancelled the Winter Storm

Previous discussion follows...
Issued at 308 AM EDT Sat Mar 17 2018

Active weather including freezing rain over northeastern sections
and thunder potential for southern sections will be be the main
focus for especially this morning. A Winter Weather Advisory for
freezing rain remains in effect through 10 am for areas near and
north of a Rushville to Lafayette line.

A surface low pressure center over northern Missouri, early this
morning, will slide southeast to near Evansville at 18z and to
southeastern Kentucky and the Appalachians late this afternoon and
this evening. Radar was showing bands of mostly moderate rain
lifting northeast over central Indiana with more upstream over
central Illinois. Temperatures have fallen below freezing in much of
the advisory area. Dew points in the upper teens and lower 20s will
also allow for evaporative cooling. That said, road temperatures
were mostly in the lower and middle 40s. So, it will take awhile for
if at all for untreated roads to freeze up. At any rate, will keep
the advisory going through 10 am after which time, model soundings
and surface temperature forecasts suggest it will be all rain. The
rain threat will be gradually ending this afternoon from northwest
to southeast as the system departs. Likely afternoon PoPs southeast
and small chance northwest look good.

Model instability progs and upstream lightning data support a
thunder mention this morning south of Interstate 70 per Forecast
Builder. Will only see a gradual warmup today with thick clouds
expected to remain most of the day. Blend highs in the upper 30s
north to the upper 40s southwest look good.


.SHORT TERM /Tonight through Monday night/...
Issued at 308 AM EDT Sat Mar 17 2018

The main focus for the short term will be on timing of the return of
the rain along with mixing potential.

High pressure will build in tonight and allow for a brief break in
the unsettled weather. Should see skies clear from the north which
will allow temperatures to bottom out in the middle 20s north and
lower 30s south per the blend. Then, should see plenty of sunshine
and warmer temperatures on Sunday. Low level thermals and full
sunshine support above normal blend highs in the 50s with high

Then, should start seeing an increase in the cloud cover from
southwest to northeast Sunday night ahead of a Rockies system.
Models hint extreme southwestern parts of the forecast area could
see a rain shower or two toward 12z Monday. Thus, left the small
blend pops in there, but confidence is low.

Confidence is higher that rain will move in from the southwest by
Monday afternoon and even higher Monday night as models agree the
system will be moving over Kentucky. Could also see the rain change
to snow from north to south overnight Monday in the wake of the
system. Blend looks good with the highest PoPs over our southern
half, closer to the low track.


.LONG TERM /Tuesday through Friday/...

Issued at 339 AM EDT Sat Mar 17 2018

Models have come into better agreement for the long term, pushing
a closed upper low south of its previous forecast track. As a
result, the surface front is also pushed south, and this will keep
the best chances for precipitation south of the forecast area.
While last night`s runs looked relatively wet through Wednesday
night, they now look dry with the southern shift. Temperatures
will run below normal through the long term with the upper low
moving through and reinforcing the eastern U.S. upper trough. High
confidence in the below normal temperatures through the period,
with moderate confidence in mostly dry conditions for most of the
long term. By Friday another system could move in and bring
chances for more widespread precipitation to the area.


.AVIATION /Discussion for the 170600Z TAFS/...
Issued at 420 AM EDT Sat Mar 17 2018

Updated current conditions and going with mainly VCSH at the sites
as more widespread precip has moved east of the sites. Still seeing
some scattered showers moving in but coverage is much less than
before. KLAF has seen some sleet and added that in previously.
Previous discussion follows...

Short term model data suggest organized lift will be passing over
the terminals through about 171100Z, so expecting high chances of
precipitation at the terminals through that time. This evening`s
upper air indicates a large elevated warm layer, so most of the
precipitation should be liquid in nature. Progged wet bulb
temperatures suggest there may a period of freezing rain at the
KLAF, and possibly the KIND terminal.

This evening`s upper air also indicated rather steep lapse rates
aloft, so there is a small threat for some lightning strikes,
especially in the vicinity of the KHUF/KBMG terminals. Chances for
direct impacts due to convection are too small to include at this

Should see ceilings fall into the MVFR category towards sunrise
Saturday. Some dry advection from the east should limit the
potential for any widespread or prolonged IFR through midday

Surface winds generally 080-110 degrees at 8-12 kts through midday





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