Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 211050

Area Forecast Discussion
National Weather Service Indianapolis IN
550 AM EST Tue Feb 21 2017

The AVIATION Section has been updated below.


Issued at 251 AM EST Tue Feb 21 2017

A series of frontal systems will bring frequent chances for
precipitation across central Indiana during the next week. A strong
system on Friday will bring and end to the warm weather and a return
to average temperatures for the weekend. This could also bring some
strong thunderstorms Friday.


.NEAR TERM.../Today/
Issued at 251 AM EST Tue Feb 21 2017

An upper trough and a cold front are bringing rain to areas near and
just east of the Mississippi River early this morning.

These features will work east into the area today. However, the
upper trough will weaken and the front will wash out across the area
as energy focuses on an upper low moving into the southern USA.

The NAM, ECMWF, and HRRR models seem to best reflect this scenario
in terms of rainfall, with rainfall diminishing across the north
today with more QPF near or south of the forecast area.

With the weakening system will keep PoPs in chance category. Will go
highest PoPs across the northwest (where northern system will be the
strongest) and across the south third or so of the area (closer to
the better forcing to the south).

With a mild start across the area, temperatures should still reach
the mid and upper 60s even with extensive cloud cover and scattered


.SHORT TERM.../Tonight through Thursday night/
Issued at 251 AM EST Tue Feb 21 2017

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

There will be some lingering forcing across the area during the
evening, so kept some low PoPs across much of the area.

Dry conditions should then prevail Wednesday into Wednesday night as
the area is in between systems most of the period. A weak cold front
will move in late Wednesday night, but little in the way of forcing
will accompany it.

Warm advection Wednesday will allow for near record temperatures,
with the highest temperatures expected west where cloud cover will
be lower.

Low pressure will begin to organize well to the west of the area
Thursday into Thursday night. 850mb flow will increase out of the
south during the period, increasing lift across the surface front.
This will result in the return of rain chances.

Highest PoPs will across the northern forecast area which will be
near/north of the frontal boundary, and it currently looks like
Thursday night will be the timing of the higher PoPs.


.LONG TERM /Friday Through Monday/...

Issued at 130 AM EST Tue Feb 21 2017

ECMWF suggests a strong cold front sweeping across Indiana On
Friday. A warm and moist air mass should be in place ahead of this
front and showers and storms will be likely as these features
pass. Mainly Dry weather will be expected for Saturday and Sunday
as a more typical winter air mass arrives in the ohio valley
associated with High Pressure in the wake of the cold front.

ECMWF then suggests on Monday that a warm front will push toward
Indiana by Monday afternoon. This will once again bring showers
back to forecast as the next work week starts.


.AVIATION /Discussion for the 211200Z TAFS/...

Issued at 550 AM EST Tue Feb 21 2017

VFR Conditions are expected to deteriorate to MVFR during this
taf period. IFR Conditions are possible toward 12Z Wednesday.

Deep upper low over the lower Mississippi River Valley will
continue to push east and stream moisture into the Ohio Valley
today. This will result in a slow top-down saturation with best
moisture to arrive by this afternoon. Forecast soundings and time
heights show lower level saturation arriving this afternoon and
persisting through the overnight and past 12Z Wed.

Dew point depressions overnight look to fall to 1-2F...and with
plentiful lower level moisture...fog and IFR CIGS will be possible
near daybreak on Wednesday.




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