Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250256
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1000 PM EST Fri Feb 24 2017

.UPDATE...
Near term Section and aviation sections have been updated below.

&&

.SYNOPSIS...
Issued at 348 PM EST Fri Feb 24 2017

A strong cold front will seep across the Ohio Valley this evening
bringing thunderstorms and the threat for severe weather. Much
colder air will expand into the area behind the front overnight and
into the weekend with scattered snow showers on Saturday. After a
dry Sunday...unsettled weather will return for the first half of
next week along with warmer temperatures.

&&

.NEAR TERM /Rest of Tonight/...
Issued at 1000 PM EST Fri Feb 24 2017

Showers will end most areas by midnight as cold front moves
on to the east.   Satellite indicated band of temporary
clearing across Illinois will push east across central Indiana
later tonight and then wrap around clouds over the upper midwest
will spread back in late tonight.   Lowered temperatures slightly
over western sections....outherwise current forecast is on track.

Temps by 12Z Saturday will be in the upper 20s to lower 30s...a
solid 40 degree drop from highs Friday.

&&

.SHORT TERM /Saturday through Sunday Night/...
Issued at 348 PM EST Fri Feb 24 2017

After our late February spring preview...winter returns abruptly for
the weekend. Forecast challenges focus on precip chances Saturday in
the wraparound moisture behind the departing low...and temperatures
throughout the weekend.

The low pressure will continue to lift out to the north-northeast
through the Great Lakes on Saturday as colder air continues to flood
the Midwest in its wake. Wraparound moisture pool in the vicinity of
the upper low will lift across the region through the first half of
the day Saturday. Deeper moisture over the northern half of the
forecast area with scattered light snow showers expected through
early afternoon. Not expecting any accums as ground temps remain far
too warm to support. Moisture will remain trapped beneath an
inversion for much of the day and with the addition of cold
advection...skies will remain mostly cloudy for much of the day with
improvements by late afternoon as drier air builds in from the west.
Gusty west-northwest winds will continue all day with the tight
pressure gradient across the region.

With the departure of the upper low off to the northeast by Saturday
evening...the rest of the short term will be quiet and cold as high
pressure  passing through the Tennessee Valley becomes the primary
influence for central Indiana. Expect skies to become mostly clear
Saturday night and remain that way for much of the day Sunday as
surface ridging passes through. Winds will finally relax Saturday
evening as well. Will start to see increasing clouds late Sunday
along with an uptick in winds as return flow develops on the back
side of the ridge and moisture advects into the Ohio Valley ahead of
the next storm system. Any precipitation though will hold off until
after dark Sunday.

Temps...coldest temperatures in over 2 weeks for most of the region
as temps remain in the 30s on Saturday then recover somewhat into
the 40s on Sunday as warm advection commences later in the day. An
overall model blend looked quite reasonable for high temps. Lows
will fall into the lower and middle 20s Saturday night...the coldest
night since February 13th.

&&

.LONG TERM /Sunday night through Friday/...
Issued at 220 PM EST Fri Feb 24 2017

Sunday night a front forms south of the area and an upper wave
approaches. This could bring a slight chance for rain to the
southern counties and a slight chance for a mix of rain and snow
to the central counties. On Monday the chances increase, still
with the highest chances across the south and east. There could be
a few hours of rain/snow mix potential, but after 10 am Monday
any precip should be rain. The temperature will warm quite a bit
and highs Monday will be back in the low to mid 50s. Rain chances
continue through Wednesday night, with models showing a frontal
system approaching and moving through the area early to mid week.
Confidence is still fairly low as ensembles and operational
solutions still vary a decent bit. However from Tuesday afternoon
through Tuesday night there are overlapping areas of instability
in the ECM and GFS for parts of the area, thus have added a slight
chance for thunderstorms to those areas during that time. In the
wake of the frontal system passage on Wednesday, temperatures will
drop back to near or slightly above normal for Thursday and
Friday.

&&

.AVIATION /Discussion for 25030Z KIND TAF Update/...
Issued at 1000 PM EST Fri Feb 24 2017

Minor tweaks made to KIND TAF to better match current conditions.
No other changes are needed at this time.  Portion of previous
aviation discussion follows...

VFR ceilings lowering to MVFR late tonight and early Saturday.

Strong low pressure over Lake Michigan and a trailing cold front
extended south across central Indiana.  Showers and thunderstorms
had developed along this front and will impact KIND and KBMG TAF.
Otherwise...wrap around clouds behind the cold front will spread
east across central Indiana tonight and Saturday.  These clouds will
scatter out at KHUF and KBMG late Saturday as a ridge of high
pressure builds into the middle Mississippi valley.

Winds will be west up to 15 knots and gusts up to 25 knots tonight
and Saturday due to a tight pressure gradient.  Brief higher winds
are possible in thunderstorms early on.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...Ryan
NEAR TERM...Ryan/JH
SHORT TERM...Ryan
LONG TERM....CP
AVIATION...JH



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