Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 011732

Area Forecast Discussion
National Weather Service Indianapolis IN
1232 PM EST Thu Dec 1 2016

The AVIATION Section has been updated below.


Issued at 239 AM EST Thu Dec 1 2016

High pressure is expected across the area through the end of the
week. A weak upper trough is expected to move across the area around
Sunday. A low pressure system may affect the area around next


.NEAR TERM /Overnight/...

Issued at 934 AM EST Thu Dec 1 2016

Surface analysis this morning shows Low pressure in place over
Ontario/Quebec with broad cyclonic flow in place across the Great
Lakes and Ohio Valley. Satellite shows extensive cloud cover in
place across the region associated with the flow. Winds were
westerly across the area and temps were in the middle 30s.

850mb analysis shows weak cold air advection in place...with 850mb
temps near -4c to -6c. Forecast soundings today show trapped lower
level the form of stratocu expected to last through
the day with an trapping inversion aloft. Forecast soundings also
show plenty of lower level moisture available. Thus have aimed
for a cloudy to mostly cloudy sky today With little sunshine
expected amid the ongoing weak cold air advection...look for
nearly steady temperatures today...with minimal rises.


.SHORT TERM /Tonight through Saturday night/...
Issued at 239 AM EST Thu Dec 1 2016

Dry weather expected for most of this period as upper low over the
Great Lakes gradually shears out to the east, leaving a split flow
in its wake. At the surface, high pressure will build into the area
by the weekend.

The 850mb cold pocket looks like it will hold over the Great Lakes
until around Saturday, before lifting off to the northeast. As a
result, it may be until Friday night before significant clearing
takes place, especially over the northern zones.

By Saturday night, models suggest an upper trough in the northern
stream may approach the area from the west. At this time, it appears
main precipitation threat from this system will be after this
forecast period. Will bring in some small chance PoPs for light
mixed precipitation late Saturday night over the far southwest zones.

Progged low level thicknesses and expected cloud cover suggest the
GFS MOS highs for the next couple of days are probably too warm.
Will cut about 2-5 degrees off of the guidance highs Friday and
Saturday. Guidance lows look OK for now.


.LONG TERM (Sunday through Thursday)...
Issued at 224 AM EST Thu Dec 1 2016

Significant model discrepancies exist regarding handling of multiple
systems expected to impact central Indiana during the long term
portion of the forecast, which may have a major impact on
precipitation types and timing. See little reason to make
significant deviations from blended initialization as a result.

At least 3 separate systems look poised to bring at least a chance
of precipitation to the area during the week, with low level
thermals borderline for a few snowflakes at times.


.AVIATION /Discussion for the 018100z TAFS/...

Issued at 1231 PM EST Thu Dec 1 2016

MVFR Cigs are expected through the period.

Forecast soundings and Time height sections continue to suggest
plentiful lower level moisture lingering through the taf period.
Forecast soundings suggest a trapping inversion aloft...keeping
the stratocu in place across the area amid the broad cyclonic

Surface ridging is not expected to pass until at least Friday
afternoon...preventing much in the way of clearing and possible
anticyclonic flow. Thus MVFR CIGS through the period.




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