Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 281845
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
245 PM EDT Sun May 28 2017

.UPDATE...
The SYNOPSIS...NEAR TERM...SHORT TERM and LONG TERM Sections have
been updated below.

&&

.SYNOPSIS...
Issued at 241 PM EDT Sun May 28 2017

A cold front will pass through the area later this afternoon and
evening. A couple of weak upper disturbances may affect the area
during the early to middle parts of the week. A frontal system may
affect the area towards the end of the week and on into next
weekend.

&&

.NEAR TERM /Rest of This Afternoon and Tonight/...
Issued at 241 PM EDT Sun May 28 2017

Convection developing over the far northwest zones near a surface
cold front and mid level vorticity tail. Air mass remains
moderately unstable locally, so area of convection should continue
to develop and move southeast during the course of the afternoon
and evening in tandem with the surface front and upper air
feature. Short range model data suggest this feature will pass off
to the southeast by 290400Z, so will cut off the PoPs at that
time.

This morning`s upper air indicates adequate mid level lapse rates
remain over the area for severe convection, however deep layer shear
is quite weak. Short term models suggest deep layer shear may
increase later this afternoon and evening with the approach of the
vorticity tail.

Progged low level thicknesses suggest the GFS MOS guidance lows for
tonight look good overall.

&&

.SHORT TERM /Monday through Wednesday/...
Issued at 241 PM EDT Sun May 28 2017

Model data indicate an upper low will slowly progress across the
upper Great Lakes during this period. Appears a mid level speed max
within the upper flow will pass through embedded within the h the
southern Great Lakes Monday afternoon and night. Models suggest
there may be a decent amount of lift with this feature, along with
some instability. Will go with chance PoPs for Monday afternoon and
night. Deep layer shear looks fairly strong, so gusty winds may
accompany any stronger convection.

Another upper disturbance may move across the area around Tuesday
night. At this time, ensembles aren`t too bullish with this feature,
but most of the operational models are indicating a precipitation
threat with this feature for mainly Tuesday night. Will go with
chance PoPs for showers at that time.

Progged low level thicknesses suggest the GFs MOS temperature
guidance through the period looks reasonable for the most part, so
little if any adjustments planned.

&&

.LONG TERM /Wednesday Night Through Sunday/...
Issued at 241 PM EDT Sun May 28 2017

Confidence is low in this part of the forecast. ECMWF suggests
mainly NW flow in place across Indiana due to some ridging in place
across the Western plains. THe eCMWF suggest little in the way of
dynamics passing Indiana until Saturday and Sunday morning with
this flow...however...forecast builders blend includes some pops
nearly every day. A warm front does look to surge across Indiana On
Thursday...placing Indiana within the warm sector once again with
more of a southerly surface flow. Furthermore a stronger Cold front
looks to pass late Saturday into Sunday. This forecast feels best
chances will be on Saturday and Saturday night when the deepest warm
and moist air arrives along with some support aloft.
However...models just are not that good handling these weak...subtle
waves. Confidence is low.

&&

.AVIATION /Discussion for the 281800Z TAFs/...

Issued at 150 PM EDT Sun May 28 2017

Mainly VFR Conditions are expected this TAf period.

Showers and TSRA are expected at the TAF sites through the first
3-5 hours of the TAF period as a cold front over NW Indiana will
push southeast across Indiana. Favorable conditions exist ahead
of the front with forecast soundings suggesting steep lapse rates
and CAPE over 1500 j/kg. Brief MVFR to IFR conditions will be
possible with any thunderstorm that strikes a TAF Site.

Subsidence and drying is expected in the wake of the front as
time height sections show a dry column into Monday.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....Puma
AVIATION...JP



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