Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 290809
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
309 AM EST Tue Nov 29 2016

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

&&

.SYNOPSIS...
Issued at 305 AM EST Tue Nov 29 2016

A low pressure system is expected to move through the Ohio Valley
tonight into Wednesday. In the wake of this system, high pressure
will build into the area for the latter parts of the week. Another
frontal system may affect the area late this weekend and early next
week.

&&

.NEAR TERM /Today/...
Issued at 305 AM EST Tue Nov 29 2016

Dry conditions expected today in the wake of yesterday`s upper
trough, currently lifting off to the northeast across the Great
Lakes. Short term model guidance suggest low clouds currently
across the area should clear out of the eastern zones around
sunrise. However, extensive mid and high level cloud upstream
should begin moving into the area later this morning and this
afternoon. This should result in quite a bit of cloud cover in one
form or another today.

Low level thicknesses suggest the GFS MOS highs for today look good
for the most part.

&&

.SHORT TERM /Tonight through Thursday night/...
Issued at 305 AM EST Tue Nov 29 2016

Model data suggest another short wave trough, currently dropping
southeast through the southern Rockies, will eject out across the
Ohio Valley during the day Wednesday. This will help to induce a
surface wave on the trailing frontal zone tonight. Based on the
location of the low level jet associated with this system, the best
lift will probably be located near and south of the Ohio river.
However, the northern fringes of this system may affect parts of the
local area tonight into Wednesday. Will go with chance PoPs for
rain over about the southeast two thirds of the area from late
tonight into Wednesday.

Rest of the short term looks dry at this point, as remnants of old
upper low shear off to the east, and surface high pressure noses
into the Tennessee Valley.

The GFS MOS highs for Wednesday look too warm, given cloud cover and
precipitation potential. Will nudge the guidance highs down about a
category in that period. Remainder of the guidance temperatures look
reasonable based on progged low level thicknesses.

&&

.LONG TERM /Friday Through Monday/...
Issued at 305 AM EST Tue Nov 29 2016

Model Ensembles indicate high pressure will dominate our weather
early in the long term followed by an area of low pressure and
an upper trough early next week.   Models are in pretty good
agreement Friday and Saturday and poor agreement early next week.

One difference regards timing as the GFS brings the bulk of
precipitation our way Monday...while the GEMNH and EURO brings
most of it our way Sunday and Sunday night.  The GFS brings
an initial upper disturbance our way early Sunday as well and
then weakens it with it bringing the main system Monday.

There are more similarities between the GEMNH and EURO with the
main difference is that the EURO may be overly deep with the surface
low.  With this in mind...will lean more towards the GEMNH and EURO
timing and the GEMNH with a weaker surface low.   Low level
Thickness of the EURO and GEMNH favor mostly liquid precipitation
early next week and even the GFS is all liquid as well.  As a result
decided to down play mention of snow and also bumped up low
temperatures a little Saturday night.    Another adjustment was to
increase sky cover a little Sunday to coincide with the EURO and GFS
solution.

The model blend and GEMNH and EURO indicate should end Monday and
will follow suit with this forecast.

&&

.AVIATION /Discussion for the 290600z Tafs/...

Issued at 1100 PM EST Mon Nov 28 2016

VFR conditions are expected for much of this TAF Period.

CONSshort not doing well handling the arrival of the dry slot.
CONSshort keeps IFR CIGS across the area overnight...however
based upon latest observational and satellite trends...that
appears quite unlikely. DRy air continues to stream into the
system from the southwest. Gradient winds are expected to remain
strong overnight...providing mixing. Little in the way of cold air
advection is expected tonight. Thus the VFR conditions upstream
are expected to quickly arrive across Central Indiana during the
next few hours...persisting through much of Tuesday.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....JEH
AVIATION...JP



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