Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 222337

Area Forecast Discussion
National Weather Service Northern Indiana
737 PM EDT Sun Oct 22 2017

Issued at 734 PM EDT Sun Oct 22 2017

Rain continues to move into the area and will affect areas mainly
west of Interstate 69 tonight as a front moves east. Rain will
likely engulf the entire forecast area Monday into Monday evening
as low pressure develops into the Great Lakes region. Rainfall
amounts between 1 and 3 inches will be possible in northeast
Indiana, northwest Ohio, and south- central Lower Michigan. Much
cooler and showery weather is expected behind this system into
Tuesday and Wednesday, with highs on Wednesday likely struggling
to get out of the 40s.


.SHORT TERM...(This Evening through Monday Night)
Issued at 313 PM EDT Sun Oct 22 2017

Relatively weak showers were developing ahead of the front near the
IL/IN border in an area of low level theta e convergence. On Sunday
afternoon, the front was near Lincoln IL and extended northeast
toward Chicago. The upper low will move northeast across the Ohio
River Monday as the trof becomes negatively tilted and as the front
moves east. This will cause rapid cyclogenesis and a significant
deformation zone to form on the northwest section of the surface
low. Continue to favor the ECMWF which has gained support from the
NAM with the 12Z run. Heavy rain is likely over northern Indiana
into far northwest Ohio and far southern Lower Michigan. Have
coordinated with the Ohio RFC and neighboring offices in this regard
for heavy rain the possibility of an areal flood watch, but
following much discussion and reflection, decided to hold off with
the watch given very dry conditions at the onset. Also, although
rainfall amounts of 1.25 to 2.5 inches are expected, runoff
should be more gradual helping to reduce the chance for
widespread flooding concerns. Will continue to mention localized
flooding in the Hazardous Weather Outlook.


.LONG TERM...(Tuesday through Sunday)
Issued at 313 PM EDT Sun Oct 22 2017

Much colder air will spread across the Upper Great Lakes region
Tuesday accompanied by lake enhanced showers with delta T values
rising to or exceeding 15C. Highs Tuesday should only be between 50
and 55, and then cooling to around 48 Wednesday as 850 mb
temperatures fall below 0C. Lowered highs Tuesday to around 50 over
most areas as 850 mb temps fall below 0C. There should be a short
break in the rain Wednesday night through Thursday night before the
next system arrives. Colder air is expected to arrive this weekend
with lows dropping close to freezing Sunday morning.


.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 734 PM EDT Sun Oct 22 2017

Cold front enters from the west bringing rain and reduced CIGs
and VISBY by Monday morning. As of forecast issuance, many
stations along and just behind the front have IFR conditions.
Overnight, believe the best chance for IFR conditions will be at
SBN as the front stalls since it doesn`t quite reach FWA by Monday
morning. Fuel alternate MVFR conditions appear most likely at FWA
as of this forecast issuance, but could dip into IFR Monday
morning as well.

Rain is then expected to continue into Monday as a low pressure
system rides north along the front through the area and reduced
conditions are expected to continue into the day as a result.


LM...Small Craft Advisory until 11 PM EDT this evening for LMZ043-046.



SHORT TERM...Skipper
LONG TERM...Skipper

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