Area Forecast Discussion
Issued by NWS Indianapolis, IN

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667
FXUS63 KIND 242021
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
320 PM EST Fri Nov 24 2017

.UPDATE...
The AVIATION Section has been updated below.

&&

.SYNOPSIS...
Issued at 255 PM EST Fri Nov 24 2017

A cold front will sweep across central Indiana tonight with clouds
and perhaps a few sprinkles. High pressure will then build in for
the weekend and the first half of next week with quiet weather...
mainly clear skies and seasonable temperatures. The next chance for
rain will come during the latter half of next week as low pressure
tracks into the Great Lakes.

&&

.NEAR TERM /Tonight/...
Issued at 255 PM EST Fri Nov 24 2017

Very nice afternoon in progress as warm advection and increasing
southwest flow pumping mild air into the Ohio Valley. Much of
central Indiana were enjoying temperatures in the mid and upper 50s
at 18Z.

Temperatures are likely to creep up another degree or two most areas
with compressional heating and warm advection ahead of an
approaching cold front. Could see a few locations around 60 degrees
before the end of the day.

Focus then shifts to the aforementioned cold front...poised to swing
across central Indiana tonight. The boundary is located back across
the upper Midwest this afternoon with an axis of clouds and light
precipitation tailing the boundary. As the front moves into the
region later this evening it will be accompanied by a vort lobe
aloft and some mid level deformation. Moisture profiles continue to
look unimpressive and the bulk of the forcing aloft will be off to
the northeast. While the setup looks weaker than previous model
runs...still feel the presence of the vort lobe and deformation
aloft will enable a few sprinkles or very light rain showers to
accompany the boundary tonight and will maintain a chance for
sprinkles. The front and any light precipitation will be east of
central Indiana prior to daybreak. Expect periodic wind gusts to
continue through the evening...especially over the northern half of
the forecast area before diminishing overnight.

Temps...with a period with clouds overnight and surface flow
remaining up most of the night...trended low temperatures closer to
the warmer MAV guidance. Most locations will fall into the upper 30s
and lower 40s.

&&

.SHORT TERM /Saturday through Monday/...
Issued at 255 PM EST Fri Nov 24 2017

Forecast challenges are few through the entire short term as a broad
area of high pressure serves as the primary influence on weather
across the Ohio Valley through early next week.

High pressure will drift out of the northern Plains on Saturday and
eventually settle over the Tennessee Valleys by early next week.
Predominant northwest flow aloft through much of the short term will
maintain slightly cooler temperatures through the weekend before
warm advection and southwest flow develop Monday on the back side of
the surface ridge. Weather will be pleasant through the period with
mainly clear skies as any upper level waves remain well to the north
and east of the region. Travel conditions through the weekend will
be superb.

Temps...cold advection behind the front will bring slightly cooler
temperatures for much of the weekend but still near normal for late
November ranging from the mid 40s to lower 50s. Warmer temperatures
return for Monday with the entire area into the 50s. Generally
utilized a model blend for highs Saturday and Sunday...then trended
above most guidance on Monday. Lows will be seasonable through the
period.

&&

.LONG TERM /Monday night through Friday/...
Issued at 220 PM EST Fri Nov 24 2017

Focus for the extended will be timing of pops. Models trending
slower in brining showery weather to central Indiana next week. The
12z GFS is now not brining any QPF to the area until Wednesday
afternoon associated with a Pacific system. The 00z ECMWF was even
slower. Prior to that good confidence that high pressure over the
southeastern states and southerly flow around it should allow for
dry weather with above normal temperatures. Blend has a good handle
on this. Should see highs well into the 50s Monday through Thursday.
Could even see 60 degrees at some locales, especially Tuesday. With
more cloud cover and northerly low level flow in the wake of the low
pressure system, look for near to below normal temperatures by next
Friday. Would not completely rule out any lingering rain showers
mixing with snow briefly at the tail end Thursday night, however
with lows in the mid 30s, will go with all rain.

&&

.AVIATION (Discussion for the 24/21Z IND TAF Update...
Issued at 320 PM EST Fri Nov 24 2017

No changes needed to the TAF.

Previous discussion follows...
Issued at 1120 AM EST Fri Nov 24 2017

High confidence in VFR conditions through 09z Saturday. Then, the
GFS LAMP suggests there could be come MVFR ceilings near and behind
a cold front, that will move through from the northwest 06z-12z. The
SREF, meanwhile supports VFR through the period. With it being so
far out, we will go optimistic for now.

Winds will be southwest today to 15 knots with gusts possible. Winds
will drop to 10 knots or less overnight and shift to the northwest
behind the cold front.

&&

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

&&

$$

SYNOPSIS...Ryan
NEAR TERM...Ryan
SHORT TERM...Ryan
LONG TERM...MK
AVIATION...MK



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