Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 200752 CCA

Area Forecast Discussion
National Weather Service Northern Indiana
341 AM EDT Sun Aug 20 2017

Issued at 318 AM EDT Sun Aug 20 2017

High pressure over the Appalacians will continue to provide fair
weather across our area today through Monday morning. The southerly
flow around this high will result in warmer and more humid
conditions the next couple of days. A strong cold front will move
southeast across our area Tuesday, with showers and scattered
thunderstorms likely along and ahead of the front. High pressure
will move slowly east across the Great Lakes Wednesday through
Friday, and to the New England coast this weekend providing dry
weather across our area through this timeframe. Temperatures will be
well below normal late this week, but a gradual warming trend is
expected over the weekend.


.SHORT TERM...(Today and Tonight and Monday)
Issued at 318 AM EDT Sun Aug 20 2017

Cluster of tstms over ern Neb/wrn IA expected to move east today but
should dissipate or curve se toward greater instability before
reaching our area. Mostly sunny skies and wk waa should allow temps
to reach the m80s across our area this aftn. Another cluster of
storms expected to develop a little farther east over IA at nose of
LLJ tonight. MCV from this activity should drift east across our
area Monday aftn as diurnal instability conts to increase. An
isolated shower psbl nw portion of the cwa in enhanced low level
waa/winds ahead of this feature late tonight and Monday morning
but better chance as it moves through Monday aftn. With very warm
airmass in place by Monday, expect sufficient heating for temps
to mix out into the u80s, barring unforeseen widespread
convection or sgfnt outflow boundary disruption.


.LONG TERM...(Monday Night through Saturday)
Issued at 318 AM EDT Sun Aug 20 2017

Strong shrtwv will dig se across the upr Grtlks Mon ngt-Tue with
associated sfc cdfnt movg across our area Tue. NAM/GFS/ECMWF/GEM
in decent agreement suggesting showers/tstms will overspread our
area ahead of the front late Monday night and Tue morning during a
period of relatively low instability. This convection would likely
limit destabilization Tue as the front moves through. However, NAM
3km suggests this pre-frontal convection will only impact the
n-nw portion of the cwa Monday night, psbly allowing for more
sgfnt destabilization across the s-se portion Tue ahead of the
front. If sgfnt destabilization does occur, a few svr storms psbl
as strong deep layer shear should be in place by that time.

Sfc high will move slowly ese from the nrn Plains Tue ngt across the
grtlks to thu-sat and to the new england coast by Sunday providing
dry conditions through this period. Temps will be well blo normal
Wed-Fri but grdly warm back to near normal over the weekend as deep
ern U.S. upr level trof moves slowly east and wk ridging crosses the


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 110 AM EDT Sun Aug 20 2017

Have left tempo mvfr vsbys at KFWA on the 8 to 12z window for
some patchy fog. No strong signals of anything more than that at
this time. Anything that may form will quickly burn off with
little more than some fair weather cu in the afternoon. Winds will
remain generally 6 knots or less.





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