Area Forecast Discussion
Issued by NWS Indianapolis, IN

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043
FXUS63 KIND 241901
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
300 PM EDT Fri Mar 24 2017

.UPDATE...The SYNOPSIS...NEAR TERM and SHORT TERM sections have been
updated below.

&&

.SYNOPSIS...
Issued at 300 PM EDT Fri Mar 24 2017

A pair of weather systems will bring numerous showers and a few
thunderstorms to central Indiana this weekend and early next week.
After a brief dry period during the middle of next week, a southern
system will bring more showers to the area late next week.

Look for seasonable to slightly above average temperatures and highs
mostly in the 60s.

&&

.NEAR TERM.../Tonight/
Issued at 300 PM EDT Fri Mar 24 2017

Shower timing and coverage will be the main focus tonight.

Models agree that an upper low, seen in water vapor imagery over the
Texas and Oklahoma panhandles this afternoon, will move to
southwestern Missouri by 12z Saturday. Energy rounding the base of
this feature will eject northeast across the Ohio Valley and Great
Lakes overnight. In addition, 50 plus know low level jet will bring
increased moisture to especially areas west of Indiana 37. Thus,
will go with likely pops west and taper to low chance pops east. The
eastern counties may not see any showers until after 12z Saturday.

The southerly winds and increasing cloud cover should result in mild
overnight lows in the mid and upper 50s.

&&

.SHORT TERM.../Saturday through Monday/
Issued at 300 PM EDT Fri Mar 24 2017

Showers and thunderstorms will be the main focus this weekend into
Monday.

Models and ensembles with are similar as they open up an upper low
over the Great Lakes on Sunday and have a trailing upper trough move
to the middle Mississippi Valley late Monday. The GFS is a faster
and ECMWF slower with the first feature and the GFS is a fast
outlier with the second. A cold front will be moving through the
area late Saturday into Sunday morning. Deep moisture and synoptic
scale forcing will result in showers overspreading the area from
west to east Saturday into Sunday morning. As the front moves east
of the area and upper trough to the northeast, the showers will be
diminishing late Sunday and Sunday night. However, more southerly
flow and trailing upper trough will result in more widespread
showers moving from the east on Monday.

Model instability progs were showing enough instability this weekend
and early next week for at least isolated thunderstorm chances each
period. However, not expecting an organized severe threat.

Mild model blend temperatures reflect the southerly winds but
widespread cloud cover. However, blend temperatures look a little
too cool on Saturday. After coordination with adjacent offices,
raised temperatures a couple of degrees to the upper 60s and mid
50s. For the rest of the time, look for highs in the 60s and
possibly even lower 70s south on Monday.

&&

.LONG TERM /Monday Night through Thursday Night/...

Issued at 237 PM EDT Fri Mar 24 2017

Back to back low pressure systems are still expected to affect
the forecast area during the extended period. The period will
start out though with most of the first system already through
the area. As a result, the thunderstorm threat will diminish by
Monday night with just rain showers lingering into Tuesday. After
that, a ridge will strengthen over the area for mid-week,
resulting in dry conditions from Tuesday night through Wednesday
night. At that point, the next system tracking through the
Missouri Valley will move closer to central Indiana. So, rain will
spread across the forecast area from west to east on Thursday,
increasing in coverage by Thursday night.  Meanwhile,
temperatures through the period will be above normal with highs
generally in the 60s and lows in the 40s and 50s.

&&

.AVIATION /Discussion for the 241800Z TAF Issuance/...
Issued at 1249 PM EDT Fri Mar 24 2017

Good confidence that VFR conditions will prevail through at least
05z. After that, expect showers to gradually spread east across the
terminals. Should still be mostly VFR, but MVFR conditions can not
be ruled out. Also, would not rule out thunderstorms, but chances
too low to mention.

Winds will be southerly 15 to 20 knots through 02z or so and then
drop to 10 knots or less overnight before gusty winds return after
14z Saturday. Also, could see some low level wind shear at LAF from
07z-13z as a low level jet moves in from the west.


&&

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

&&

$$

SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....TDUD
AVIATION...MK



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