Area Forecast Discussion
Issued by NWS Indianapolis, IN

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433
FXUS63 KIND 280437
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1237 AM EDT WED SEP 28 2016

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

&&

.SYNOPSIS...
Issued at 221 PM EDT Tue Sep 27 2016

An upper level low is expected to drift southeast from the
upper Great Lakes into the Appalachian mountain region towards
the end of the week.

&&

.NEAR TERM /Tonight/...

Issued at 946 PM EDT Tue Sep 27 2016

With clouds coming in and winds staying up, it may be difficult
to hit min temps. However scattered showers along with dewpoints
in low to mid 40s may still help achieve current forecast mins
through evaporational cooling so will leave mins where they are.
High Res rapid refresh model still indicating, like NAM, that
scattered showers near Lake Michigan should rotate SE into many of
our counties by daybreak. All models also break out second precip
area in our SE counties before daybreak and have this reflected in
late night pops as well.

&&

.SHORT TERM /Wednesday through Friday/...
Issued at 221 PM EDT Tue Sep 27 2016

Models suggest strong vorticity lobe, in conjunction with upper
low, will move through the local area during the day on
Wednesday. Will continue with chance PoPs all areas on Wednesday.
Steepening mid level lapse rates during the day suggest some
lightning strikes are possible, especially over the southeast
zones, where passage of vorticity lobe will coincide with peak
heating.

Appears some shower threat will probably linger through Friday
as upper low gradually drifts southeast into the Appalachian
mountain region towards the end of the period. Will keep chance
PoPs in the forecast through Friday all areas for now, but it
appears the best threat will be over the eastern and southeastern
zones after Wednesday, closest to upper low.

Based on progged low level thicknesses, the GFS MOS highs for
Wednesday and Thursday look too cool. Will raise the guidance a
category or so in those periods. Guidance lows look OK for now.

&&

.LONG TERM /Friday Night through Tuesday/...

Issued at 220 PM EDT Tue Sep 27 2016

The ECMWF continues to keep the persistent upper low over the
Ohio Valley Friday night through Saturday...before it finally
begins to drift farther north on late Saturday night and Sunday.
ECMWF then suggests ridging aloft build across the
region...nudging the low to the northeast. Thus have kept with
superblends low chance pops from Friday Night into Saturday...then
trended toward a dry forecast early next work week as ridging and
high pressure resume. Expect below normal temperatures to continue
on Friday and early Saturday as the low lingers in the area...a
return to near normal highs is expected next work week as high
pressure builds across the region and warmer southerly flow tries
to develop.

&&

.AVIATION /Discussion for the 28/06Z TAFs/...

Issued at 1236 AM EDT Wed Sep 28 2016

VFR conditions may give way to MVFR in stratus and showers later
this morning across the sites as a large upper low drops into the
region.

Skies will quickly cloud up overnight as the upper low approaches.
Fluctuations in conditions will be likely on Wednesday, with the
lowest conditions likely in any showers or perhaps an isolated storm
or two.

Winds will become more northwesterly with time, and will be 10kt or
less throughout the period.

Visibilities will be unrestricted except for minor restrictions in
precipitation.

&&

.IND Watches/Warnings/Advisories...NONE.

&&

$$

SYNOPSIS...JAS
NEAR TERM...TUCEK
SHORT TERM...JAS
LONG TERM...PUMA
AVIATION...NIELD



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