Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 202045
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
345 PM EST Tue Feb 20 2018

.SYNOPSIS...
Issued at 344 PM EST Tue Feb 20 2018

Very wet and mild weather will continue through Wednesday morning.
Heavy rainfall will lead to flooding on rivers, streams, and low
lying areas prone to flooding. A brief shot of colder temperatures
is in store Wednesday into Thursday behind the cold front, which
will bring a light wintry mix to the area.

&&

.SHORT TERM...(Tonight through Wednesday)
Issued at 344 PM EST Tue Feb 20 2018

Flooding event well underway in our NW counties while areas to the
southeast thus far have generally been spared. Trends in models
continue to point towards a rather NW to SE gradient between
continued/worsening flooding impacts and minor issues. Flood watch
will remain in place for the time being with confidence low on
exact evolution for SE areas.

Where the rain has been falling 2 to as much as 5 inches of rain
has already been reported. While many areas may see a brief lull
in the precip, the cold front will come sweeping through with some
of the high res models showing potential for several inches of
additional rain in the NW. Have stayed very conservative in terms
of QPF but still coming up with 1.5 to over 2 inches NW with
locally higher amounts a concern. For the SE, amounts may be too
low, but confidence in residence time of any precip over these
areas is low resulting in status quo.

Cold air will quickly undercut the warm air aloft and bring some
potential for freezing rain in NW areas late tonight into early
Weds. Low confidence in exactly how fast surface temperatures will
fall and more importantly road/object temps that have been warm
for a few days. Passing mention in grids but no accumulations
expected at this time and no headlines for the moment.
Precipitation may linger into the afternoon in SE areas as front
will be slow to push further away with main upper trough still
holding to the west of the region.

&&

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 344 PM EST Tue Feb 20 2018

Few changes to long term with focus on flooding threat in short
term.

Frontal boundary will have cleared the area to the southeast, but
longwave trough will remain rooted to the west of the region,
resulting in a meandering frontal boundary through much of the
period.

Early in the period thermal profiles get a bit dicey as we remain on
the colder side of the boundary with mixed precip possible with each
wave into Saturday with greatest concern being during the overnight
hours of Thursday night into early Friday period. With focus on
short term have not had much time to look over closely, but signal
warrant at least a continued mention of mixed precip in parts of the
area that could cause some minor travel issues.

Frontal boundary will shift further NW as stronger wave and area of
low pressure move along it and bring another shot of what should
mainly be liquid precip. System seems more progressive which should
help limit QPF amounts, however, with flooding still likely ongoing
in many areas could cause either delayed or secondary crests in some
rivers.

 &&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1227 PM EST Tue Feb 20 2018

Heaviest rain and greatest impacts currently residing both TAF
sites, with KSBN likely to get back into IFR conditions over the
next several hours as band of rain that temporarily shifted SE
moves back in. In addition, cold front will sweep in tonight with
lower cigs/vsby and continued rain resulting in IFR and possible
LIFR conditions. KFWA will likely remain on the eastern edge of
the precip and may see highly variable conditions through the
afternoon and early evening, but will eventually drop into IFR
later this evening into the overnight hours. A few lightning
strikes are possible at both sites through tonight, but
low confidence on coverage/impacts on the airports so will leave
out.

While concerns are low at this point, the rain could end as a
period of light freezing rain at both sites near/after 12Z Weds as
colder air rushes in. Surface temperatures and warm raindrop
temperatures may prevent any icing, but something that will be
monitored.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch through Wednesday afternoon for INZ003>009-012>018-
     020-022>027-032>034.

MI...Flood Watch through Wednesday afternoon for MIZ077>081.

OH...Flood Watch through Wednesday afternoon for OHZ001-002-004-005-
     015-016-024-025.

LM...Small Craft Advisory until 7 PM EST this evening for LMZ043-046.

&&

$$

SYNOPSIS...Fisher
SHORT TERM...Fisher
LONG TERM...Fisher
AVIATION...Fisher


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