Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 182051

Area Forecast Discussion
National Weather Service Indianapolis IN
451 PM EDT Sun Mar 18 2018

The AVIATION Section has been updated below.


Issued at 244 PM EDT Sun Mar 18 2018

A low pressure system is expected to move through the Ohio Valley in
the Monday to Tuesday time frame. In the wake of this system, high
pressure will move across the area during the middle and later parts
of the week. Another low pressure system may affect the area by next


.NEAR TERM /Tonight/...
Issued at 244 PM EDT Sun Mar 18 2018

Should see a gradual increase and thickening of cloud cover tonight
in advance of the next system. Moisture and lift progs off the
models suggest the precipitation threat will remain off to the
southwest of the forecast area tonight, so will go with a dry

Low level thicknesses generally support the GFS MOS lows tonight, so
little if any adjustments will be made.


.SHORT TERM /Monday through Wednesday/...
Issued at 244 PM EDT Sun Mar 18 2018

Model data suggest upper trough currently over the Rockies will
drift east and settle over the Ohio Valley by Tuesday and

Organized lift will begin moving into the southwest zones during the
day Monday, although it appears the system will be fighting a lot
dry advection from the northeast. As a result, it doesn`t appear
there will much of a precipitation threat until Monday afternoon.
Will bring in PoPs over the southern and central zones during Monday

Model data suggest the deformation zone will most likely set up over
the southern zones Monday night, so will go with the highest PoPs
there, and taper them off farther north. As is typically the case,
there will probably be a sharp cutoff to the precipitation along the
northern end of the deformation zone, suggesting the precipitation
threat may not reach the northern zones.

Still appears that thicknesses may lower enough by Monday night for
mixed precipitation in the deformation zone. Light snow
accumulations possible at that time.

Although the parent surface low moves off to the east by Tuesday,
there may still be a threat for rain or snow showers Tuesday into
Wednesday under the weakening upper low. Will keep some chance
PoPs for Tuesday through Wednesday for light rain or snow showers,
mainly over the southeastern and eastern zones, closest to the
upper trough axis. Some of the ensembles continue to suggest the
upper low/trough may slow down or stall. If this trend continues,
PoPs may have to be pulled farther west on Tuesday and Wednesday.

Progged low level thicknesses suggest the GFS temperature guidance
over the next couple of days is probably too warm. Will cut about
3-5 degrees off of the guidance through Tuesday.


.LONG TERM /Wednesday Night Though Sunday/...

Issued at 225 PM EDT Sun Mar 18 2018

Active Spring weather is expected late this week.

Wednesday Night through Friday morning look dry as the ECMWF
suggests High pressure over and then departing the area with
ridging in place aloft.

On Friday afternoon and NIght ...the ECMWF suggests the arrival
of a warm front from the southwest as low pressure deepens over
the plains. This low then pushes into the Mississippi Valley on
Saturday morning and across Indiana on Saturday Night along with a
cold front. Thus forecast builder has inserted high pops on
during this period as these features pass.

On Sunday...the trailing cold front pushes south to Kentucky and
Tennessee...and dry but cool air looks to return on northeast
winds. The aforementioned front looks to lingering in the area on
Sunday night...which could bring chances for rain and storms back
early next week.


.AVIATION /Discussion for the 18/2100Z IND TAF Update/...

Issued at 443 PM EDT Sun Mar 18 2018

Not much change to ongoing TAF forecast for IND as quiet VFR
conditions persist. Did increase ceiling coverage from FEW to SCT.
Otherwise, no changes. The previous discussion follows...

Issued at 114PM EDT Sun Mar 18 2018
VFR Conditions are expected this TAF period.

Models suggest dry air will remain in place tonight and much of
monday morning as High pressure over Indiana departs eastward.
Some High and mid cloud may invade the area after 18Z
time heights and forecast soundings suggest saturation aloft with
favorable lift within the column...however CIGS at that points
still look to be VFR...except within a scattered shower that could
occur late in the day.





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