Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 211634

Area Forecast Discussion
National Weather Service Indianapolis IN
1134 AM EST Sat Jan 21 2017

The AVIATION Section has been updated below.


Issued at 220 AM EST Sat Jan 21 2017

Yet another southwestern system will bring mild but wet weather to
central Indiana for the rest of the weekend. Then, a pattern shift
will bring more seasonable weather and snow showers to the area late
next week.


.NEAR TERM /Rest of Today/...
Issued at 943 AM EST Sat Jan 21 2017

Climatologically...the third week of January is the coldest part
of the entire year when averages are at their lowest. So saying
this is a pleasant morning with 14Z temps in the upper 40s and
lower 50s seems like somewhat of an understatement. The addition
of filtered sunshine through high clouds and patches of fog is a
bonus...especially considering how little of the sun that has
appeared over central Indiana during the last two weeks.

Only minor adjustments necessary for the morning update as a
spring-like Saturday is expected. Central Indiana remains wedged
between the system bringing storms and severe weather to the deep
South this morning...and low pressure over the upper Midwest. Mid
and high clouds associated with the southern system will drift
across the region for much of the day with additional clouds
arriving towards sunset as low pressure organizes over the Texas
panhandle. With that being said...should see the sun periodically
throughout the day.

Strengthening southerly flow will continue to advect warm air into
the Ohio Valley with afternoon highs 25 to 30 degrees above
normal for this time of year. Bumped up highs a degree or two as
most areas should rise into the lower and mid 60s.

Zone and grid updates out.


.SHORT TERM /Tonight through Monday night/...
Issued at 220 AM EST Sat Jan 21 2017

Forecast focus will be on system developing over the southern Plains
within the southern jet that has sent system after system our way in
recent days. This will be the last major one for the time being with
more seasonable weather coming late next week.

The 00z GFS and Ecmwf with some support from the Canadian are showing
good clustering regarding the aforementioned system as opposed the
NAM. The NAM was much more elongated with this system with a
northern sister low developing over the Ohio Valley on Sunday. The
GFS and ECMWF are much more compact and continue to favor the
preferred Mid south track. This track would favor the bulk of the
late weekend and early next week precipitation staying south of the
area. That said, precipitable water values once again climb to three
quarters of an inch to an inch overnight Saturday night and Sunday.

ECMWF and GFS blend brings the southern system to western Arkansas
12z Sunday. Moist low level inflow ahead of this system along
with ejected impulses and diffluent flow aloft ahead of it, support
at least as high as Superblend chance pops Saturday night into
Sunday night. In addition, model instability progs were showing
enough instability to keep thunder around Saturday night per the
previous forecast and SPC Day2 general thunder outlook. Regarding
additional flooding, the key will be if southern convection is able
to cut off some of our moisture. With the saturated ground, would
not rule out some of the heavier convection could cause localized
brief flooding. But, do not think the upcoming showers will
exacerbate the river flooding.

By Monday night, any lingering showers should be over our eastern
counties as the system moves over the Appalachians.

Low level thermal progs and MOS blend favor one more day of the 20
plus degree above normal temperatures for Sunday with Monday not as
mild with highs in the 40s.


.LONG TERM /Tuesday through Friday Night/...
Issued at 338 AM EST Sat Jan 21 2017

Dry conditions can be expected on Tuesday as ridging briefly
resides over the area early in the extended period. Focus,
however, then quickly turns to the next system approaching from
the Central Plains on Tuesday afternoon. Warm air will be advected
ahead of its associated warm front on Wednesday, resulting in
highs topping off in the upper 40s/low 50s. However, the cold
front on the back side will bring a quick shift back to more
winter like conditions by Wednesday night. Any lingering rain
showers across the northern counties will quickly transition to a
wintry mix and then finally snow on Wednesday night/Thursday.
Meanwhile, daytime highs for Thursday and Friday will drop into
the 30s with overnight lows in the 20s. Further out, dry
conditions will briefly return late in the extended period per
latest Superblend initialization.


.AVIATION /Discussion for 211800Z TAF Issuance/...
Issued at 1134 AM EST Sat Jan 21 2017

VFR conditions through most of tonight...with ceilings and
visibilities diminishing early Sunday as rain showers return.

Drier air wedged into the region late this morning with subtle
surface ridging between the storm system tracking across the deep
South and low pressure over the upper Midwest. All fog has
diminished over the region with mid and high level clouds from the
southern system continuing to drift across central Indiana and
filter the sun. This will continue for the rest of the afternoon
with deeper moisture associated with the next system poised to
kick into the Texas panhandle arriving into the Ohio Valley this
evening. Model soundings showing a gradual increase in boundary
layer moisture after 06Z but lower ceilings and rain showers
likely to hold off until predawn hours Sunday. Southerly winds
this afternoon will back to E/NE tonight as the surface low tracks
from west Texas into Arkansas Sunday morning.

Elongated surface wave will track through the Tennessee and lower
Ohio Valleys on Sunday with rain increasing in coverage from the
south. The redevelopment of a shallow low level inversion will
support ceilings falling into the low MVFR category and possibly
even IFR levels by Sunday afternoon. Visibilities will fall too
within rain.





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