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Area forecast discussion 
National Weather Service Indianapolis in
351 PM EDT Wednesday may 27 2015

the synopsis...near term and short term sections have been updated below.


issued at 348 PM EDT Wednesday may 27 2015

A cold front will move through Indiana this afternoon and evening
keeping thunderstorms in the forecast until tonight. Drier air and
upper ridging will move in behind the front for a dry Thursday
before the stormy pattern reasserts itself with thunderstorms likely
to start the weekend. Above normal temperatures for the next few
days will be replaced with below normal temperatures for the


Near term /this evening and tonight/...

Issued at 348 PM EDT Wednesday may 27 2015

Kind wsr88d shows a line of storms is finally forming ahead of the
front in the northwestern counties with a few small showers popping
from indy and to the northeast. There is still instability left to
tap into but shear with the system has been unimpressive. Isolated
severe storms will remain possible for the next few hours but would
not expect anything widespread at this point. Expecting scattered
thunderstorms to move east northeast across the northern half or so
of the area...with the southern counties having had their moisture
tapped out by storms to their south.

A cold front will finish moving through central Indiana fairly early
in the tonight period. Will keep chances for thunderstorms going
early ahead of the front but then go dry after it passes. Will see
skies clear out in the northwest in the wake of the frontal passage.
Clouds could hang around a little longer in the south with the front
slowing down as it nears the Ohio River. MOS numbers were in good
agreement and generally used an average. This was a bit cooler than
consensus in the north but thought it fit better with the expected
cloud cover.


Short term /Thursday through Saturday/...

Issued at 348 PM EDT Wednesday may 27 2015

Upper ridging will slide through the area Thursday/Thursday night
and this should allow for dry conditions for a day. After that
though the progressive pattern brings a series of upper waves
through that will keep a wet forecast in the offing. A cold front
will approach Friday night and move through on Saturday and this
period looks like the best timing for thunderstorms across the area.
Increased probability of precipitation to likely for Friday night as the front is moving a
bit faster this set of runs...and kept likelies on Saturday with the
front moving through.

For temperatures guidance was fairly similar and generally used a
consensus. Leaned toward the warmer lows on Friday night though with
increasing cloud cover and rain moving in.


Long term /Saturday night through Wednesday/...

Issued at 135 PM EDT Wednesday may 27 2015

The initialization from the regional blend will be used.

Confidence in this forecast is high into Monday with good agreement
between the various models.

Starting Monday night confidence becomes low. Crucial
differences arise in the handling of a surface trough...which the
GFS places right over the area but the European model has farther
south. Just where the trough ends up will have a major impact on
where convection fires. Until we can be confident about that...we
cant be confident about the most important part of the forecast.


Aviation /discussion for 271800z tafs/...

Issued at 1256 PM EDT Wednesday may 27 2015

A line of thunderstorms ahead of a front should cross the area this
afternoon and into the evening. The storms could bring winds gusting
to 30 knots or more as well as MVFR visibilities in heavy rain.
Ceilings should remain VFR even in storms.

The storms will be east or southeast of the area by 00z. After that
there should be a period of no ceilings. Ceilings will redevelop
around 45 hundred feet with daytime heating Thursday.

While visibilities should remain mostly p6sm...local IFR in fog may
develop late tonight where a lot of rain falls today.

Winds can be expected to diminish sharply after sunset and remain
too low to affect operations thereafter.


Ind watches/warnings/advisories...


near term...cp
short term...cp
long term....jk

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