Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 190747

Area Forecast Discussion
National Weather Service Northern Indiana
347 AM EDT Mon Jun 19 2017

Issued at 140 AM EDT Mom Jun 18 2017

A strong low pressure system over southeast Ontario will move
slowly northeast early this week resulting in cooler and less
humid air over our area. A couple of troughs rotating around the
Ontario low are expected to cause scattered showers and a few
thunderstorms in our area today and Tuesday. High pressure will
move across our area Wednesday providing fair weather. The high
will move east late this week as a cold front approaches from the
northwest, resulting in warmer more humid conditions with a chance
of thunderstorms.


.SHORT TERM...(Today and Tonight)
Issued at 345 AM EDT Mon Jun 19 2017

Mostly clear skies early this morning but clouds expected to
increase with approach of cold pool aloft and short wave trough
along with diurnal heating. Mid level lapse rates will steepen today
as -18c 500mb cold pool arrives this afternoon. Cyclonic flow and
weak moisture influx will aid in development of instability showers
and thunderstorms as day progresses. Just about all CAMs showing
development by late morning with max coverage mid to late afternoon.
There is a modest amount of 0-6km bulk shear in the 20-25kt range
and MLCAPE approaches 1000 j/kg with MUCAPE around 1500 J/KG. Total
Total values well into the 50s which serves as a good proxy for the
strength of cold pool aloft. Age old 50/20 rule being approached
this afternoon with sfc dew points in the mid to upper 50s while
500mb temps approach -20C. This is an indicator of potential for
hail approaching 3/4 inches. Result could be a few strong storms
today with small hail and gusty winds. Otherwise scattered showers
and thunderstorms diminishing this evening with loss of heating and
exit of short wave.

An isolated lingering shower or storm possible through mid evening
but should see partial clearing through the evening. Another
comfortable night with lows back into the upper 50s.


.LONG TERM...(Tuesday through Sunday)
Issued at 345 AM EDT Mon Jun 19 2017

Yet another short wave will drop into base of long wave trough
centered over the western Great Lakes on Tuesday. Will see
increasing chances for showers and a few thunderstorms in the north
by late morning and rest of area in the afternoon. Highs will
continue to remain in the 70s with northwest flow and developing

Surface high pressure will build into the area Tue night and
Wednesday. Should see a nice day with seasonable temperatures and
light winds. Active pattern continues with next fast moving short
wave and surface warm front approaching Wednesday night into
Thursday. Will see increasing chances for showers and storms as warm
front lifts north. This front then looks to sag back south Friday
with what appears to be best chances for widespread rainfall during
this long term period. Models have had various solutions with
respect to this frontal boundary. Latest runs suggest it will
continue pushing south with nice weather for Saturday. Still a
little leery of this given frontal orientation parallel to mid level
flow and model summer bias of pushing cold fronts too far south.
Additional complications arise with possible northward movement of
tropical remnants and its associated moisture surge. Yet another
northern stream short wave quickly approaches by late Saturday or
early Sunday in latest models runs for additional tsra chances
next weekend.


.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 139 AM EDT Mon Jun 19 2017

An upper level disturbance combined with cold air aloft this
afternoon will bring a chance for showers and isolated storms this
afternoon. Kept thunder out of TAFs for now given isolated nature
of thunder. Otherwise, winds will generally be out of the west at
7 to 10 kts.




SHORT TERM...Lashley
LONG TERM...Lashley

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