Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 230450
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1150 PM EST Sun Jan 22 2017

.UPDATE...
Aviation sections have been updated below.

&&

.SYNOPSIS...
Issued at 314 PM EST Sun Jan 22 2017

The passage of a strong low pressure from the deep South this
afternoon up the East Coast Monday will keep cloudy skies across the
region and bring a few showers for tonight and Monday. Weak high
pressure will build in with drier weather for Tuesday. The passage
of low pressure on Wednesday will finally usher a return to more
typical late January weather for late week and into next weekend
with much colder temperatures and a few chances for light snow.

&&

.NEAR TERM /Rest of Tonight/...
Issued at 950 PM EST Sun Jan 22 2017

Radar indicated very light showers across extreme southeast
Indiana as well as central and southern Ohio.  Models indicate
deeper moisture from the surface low to our southeast will rotate
into eastern sections later tonight.  Will continue low chances of
light showers central and eastern sections mainly late tonight.

Have added patchy fog to northwest sections of our region as dense
fog not that far away.  But with winds increasing overnight do not
think fog will be that much of an issue for our area.   Low stratus
across northern Indiana has already pushed into the
Kokomo...Lafayette and Terre Haute areas and will spread over the
rest of our region overnight as low level flow becomes more
northerly.  Rest of near term is on track.  Low temperatures will
range from the upper 30s to around 40 northwest to the upper 40s
southeast.

&&

.SHORT TERM /Monday through Wednesday/...
Issued at 314 PM EST Sun Jan 22 2017

Forecast challenges focus on precip chances Monday and again
Wednesday.

The intense low pressure over the western Carolinas will spiral
northeast through the short term...tracking into the Mid-Atlantic
region...then up the coast into New England and the Canadian
Maritimes as a Nor`easter. This system will still be close enough to
the region on Monday to have a direct impact on weather before
departing off to the east Monday night to be replaced by weak high
pressure.

Deeper moisture will be pulled west around the back side of the low
pressure and into the eastern Great Lakes and eastern portions of
the Ohio and Tennessee Valleys...with a continued chance for light
rain showers and/or drizzle focused over the eastern half of the
forecast area on Monday. Further west over central Indiana...skies
will remain cloudy with a lingering stout inversion around 2kft.
Conditions will improve Monday evening as the light precip departs
off to the east. RH progs and model soundings though show scattered
of clouds will be more difficult to occur as the inversion gives way
only slowly into Tuesday morning despite the arrival of weak ridging
at the surface and aloft. Suspect more pronounced scattering of the
cloud deck will not come until Tuesday afternoon as low level flow
veers to southerly and strengthens ahead of low pressure moving
through the Plains.

That surface low to the west will track into the Great Lakes on
Wednesday and swing a cold front through the Ohio Valley. Moisture
is limited and the deeper forcing will largely remain to the north
of the forecast area. Will carry low chance pops and focus them over
the northern half of the forecast area closer to the track of the
surface low. The main impact from the passage of the low and cold
front will be the begin the process of transitioning back to a more
typical late January pattern with colder air spilling into the
region for late week.

Temps...low level thermals largely supported an overall model blend
as highs through the period should range generally from the mid 40s
to lower 50s. Lows will slide back into the 30s through the period
as well.

&&

.LONG TERM /Wednesday night through Sunday/...
Issued at 216 PM EST Sun Jan 22 2017

A broad upper trough will move from the central U.S. to the
eastern U.S. during the long term and stalling as it does so. With
the upper trough settling in over the eastern U.S., expect to see
temperatures back down to normal with access to Canadian air.
Cyclonic flow across the area combined with weak upper impulses
will bring small chances for on and off precipitation through the
period, but lack of any stronger forcing mechanism means
significant dry times are likely. Precip, should it occur, would
be in the form of rain early Wednesday night before changing over
to a rain snow mix, and then snow from Thursday night on, but
again, chances are low.

&&

.AVIATION /Discussion for 230600Z TAF Issuance/...
Issued at 1150 PM EST Sun Jan 22 2017

Becoming IFR ceilings and fog overnight with LIFR conditions at
KLAF.  A slight improvement will occur Monday afternoon but most
areas will continue with IFR ceilings.

An extensive area of stratus with some fog across northern Indiana
and eastern Illinois will spread south across central Indiana next
few hours as our flow becomes more northerly. Low centered near the
smoky mountains will move east to the middle atlantic coast.  Models
rotate some moisture into eastern and central parts of central
Indiana Monday which will result in scattered light showers.

Ceilings will rise to near a thousand feet and and even better over
western sections Monday afternoon.

North winds 10 to 15 knots will become northwest Monday and decrease
to 5 to 10 knots Monday evening.

&&

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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN
LONG TERM....CP
AVIATION...JH


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