Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 231722

Area Forecast Discussion
National Weather Service Northern Indiana
122 PM EDT Mon Oct 23 2017

Issued at 325 AM EDT Mon Oct 23 2017

A soaking rain will continue into this afternoon and evening.
Rainfall amounts of 1 to 3 inches can be expected west of
Interstate 69, with less amounts into northwest Ohio. Temperatures
will trend cooler into the 50s and low 60s otherwise today.

Tuesday into Wednesday with feature much cooler conditions and
additional chances for rain showers under deep low pressure over
the Great Lakes region. Highs each day may struggle to get out of
the 40s. A brief shot of warm and dry conditions into Thursday
will be followed by another surge of cool air Friday into the


.SHORT TERM...(Today and Tonight)
Issued at 325 AM EDT Mon Oct 23 2017

Cooler with a soaking rain expected today into this
evening...especially along/west of I-69 where 1-2" plus possible...

Incoming/amplifying northern stream upper trough phase with an
opening/negatively tilted pv anomaly lifting northeast from the
western OH/TN Valleys will allow a sfc cyclone to deepen north-
northeast into northern IN by this afternoon...and into northern
Lower MI by later tonight. Rain early this morning will continue to
focus into mainly our nw IN/sw Lower MI counties along a frontal
boundary thanks to good right entrance upper jet support, low-mid
level fgen, and ample moisture (precipitable water values near 1.5"
along the frontal slope). Rain should fill in across the rest of the
area later this morning as strong QG upper forcing/trowal and deep
moisture overspread in advance of low. Forcing will then transition
to a rather mature deformation axis this afternoon/evening as the
system deepens/phases. The trend based on latest model data and
observational data favors a more westward track with deformation
pivot along/west of I-69. Expect a good 1-2 inches here with lesser
amounts and potential brief dry periods into nw OH.


.LONG TERM...(Tuesday through Sunday)
Issued at 325 AM EDT Mon Oct 23 2017

Much colder air will wrap in under filling/deep low by Tuesday and
Wednesday. Vort lobe/main trough axis rotating around the base of
the parent low will likely generate additional rain shower
activity Tuesday into Tuesday evening, heaviest and most
widespread across far nrn IN/sw Lower MI where significant lake
enhancement will occur. These areas could receive in excess of an
inch of rain, with much lesser amounts off to the east-southeast.
Rain chances and winds diminish by Wednesday as system begins to
lift out, though kept some PoPs around given cool/cyclonic flow
and the potential for lower amplitude shortwave to trail into the
backside of trough.

Shortwave ridging and surge of warmer air in advance of the next
deep layered trough amplifying into the Central US should result in
a dry/warmer Thursday. This respite from the cool weather will be
brief however as the upper trough drives another strong cold front
through sometime Thursday night or early Friday. Moisture
return/quality into the front appears limited at this time resulting
in low PoPs.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 122 PM EDT Mon Oct 23 2017

Surface low pressure beginning to rapidly deepen as it lifts
northeast across the area. Developing dry slot will bring a brief
end to moderate rain at KSBN but improved flight conditions will
not arrive until flow backs to a more westerly direction. VFR
conditions will be possible at KSBN during this time but return to
IFR expected by late tonight as CAA ramps up. Deteriorating
conditions expected at KFWA as cooler/more moist air advects into
the area. A period of IFR is possible this evening but held just
above for now given low confidence. Some improvement then expected
overnight but will still likely be hovering around fuel alternate


LM...Gale Watch from Tuesday afternoon through late Tuesday night for

     Small Craft Advisory until 2 PM EDT Tuesday for LMZ043-046.



SHORT TERM...Steinwedel
LONG TERM...Steinwedel

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