Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 290228

Area Forecast Discussion
National Weather Service Indianapolis IN
1028 PM EDT Sun May 28 2017

The NEAR TERM Section has been updated below.


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


.NEAR TERM /Tonight/...
Issued at 654 PM EDT Sun May 28 2017

Ended the pops slightly quicker tonight based on latest radar trends
and High Resolution Rapid Refresh reflectivity progs.

Previous discussion follows...
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

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 290300Z IND TAF Update/...
Issued at 1028 PM EDT Sun May 28 2017

Could see come fog late this evening and overnight. Latest ob
visibility was down to 6sm. That said, dry advection behind the cold
front should limit the fog to no worse than MVFR.

Previous discussion follows...
Issued at 651 PM EDT Sun May 28 2017

Good confidence that VFR conditions will dominate most of the TAF
period except for perhaps brief MVFR in thunderstorms at IND and BMG
and brief MVFR fog 09z-13z. Radar and High Resolution Rapid Refresh
support only holding on to thunder through 01z. After that, should
only see cirrus.

Winds will be west and southwest less than 10 knots.




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