Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 222305

Area Forecast Discussion
National Weather Service Northern Indiana
705 PM EDT Mon May 22 2017

Issued at 405 PM EDT Mon May 22 2017

Chances of light rain showers will increase later tonight across
southwest Lower Michigan and northwest Indiana as a weak
disturbance approaches from the west. Lows tonight will be in the
lower to middle 50s. Highs on Tuesday will generally be in the
lower to middle 70s. There are additional chances for
precipitation throughout this week, particularly Wednesday as a
stronger low pressure system moves across the area.


.SHORT TERM...(This Evening through Tuesday)
Issued at 353 PM EDT Mon May 22 2017

Only token chances for light rain showers clipping northwest cwa
overnight as primary focus will become increasingly displaced
westward as intense shortwave driving southward through eastern SD
aids in refocus of upper level vortex, presently near Arrowhead
Region, southward through the Mississippi Valley. Orphaned/elevated
moisture thwarted by dry sub cloud airmass as well as weak/minoring
impulses within westerly mid level flow, to likely result in few
hundredths shra at best. Raised low temps slightly northwest CWA as
cloud deck should thicken/lower radiative losses overnight.
Continued slight chance tsra along with rising shra chances for
Tuesday as upstream system continues southward dig.


.LONG TERM...(Tuesday Night through Monday)
Issued at 403 PM EDT Mon May 22 2017

More southerly dig of system over prior runs to provide prodigious
northward onslaught of deep layer moisture flux convergence through
CWA on Wednesday. Sig bump in model blended qpf as well. For now
will withhold ESF/HWO mention, however potential for renewed
flooding on the increase and may need to be addressed should later
model runs continue to center upon similar solutions. Final ejection
of system through TN Valley into western PA on Thursday to bring
diminished rainfall rates/west to east end of rainfall. Greater
diverging solutions with time into the weekend. Will maintain
consistency with chc shra/lesser chc tsra this weekend amid
minor perturbations within wswly flow into area and northward
advance of probable/diffuse warm front laid out from OK to the
Lower Ohio Valley. Northern stream systems likely to remain in
high belted/blocking pattern.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 702 PM EDT Mon May 22 2017

Wk shrtwv from ne IA to KS causing a band of shra over central IL
movg ne this eve. Stronger shrtwv digging se from SD will result in
wkng of the lead system as it moves east across nrn IN late tonight
and Tue morning. Few shra associated with the lead shrtwv may impact
SBN tngt with more shra psbl Tue as forcing associated with the
upstream system spreads into nrn IN. Central IL area of shra
likely to diminish to sct shra by the time it reaches SBN so just
mentioning VCSH in TAF for now. Dry low levels will be slow to
saturate with just alto/strato cu expected as the shrtwv moves
through. Likewise, vsbys should remain vfr at both terminals
through the period. Modest swly low level flow attm will grdly
diminish overnight and back to easterly Tue as sfc low forms over
the lwr OH valley in response to digging nrn plains shrtwv.




LONG TERM...Murphy

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