Area Forecast Discussion
Issued by NWS Northern Indiana

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129
FXUS63 KIWX 242021
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
321 PM EST Sat Feb 24 2018

.SYNOPSIS...
Issued at 320 PM EST Sat Feb 24 2018

Major to moderate flooding continues to impact portions of
northwest Indiana and southwest lower Michigan. Scattered showers
will be possible into early evening before an area of rain and a
few thunderstorms advances across the region. Breezy, but drier,
conditions arrive for Sunday with warmer temperatures in store the
first half of the work week.

&&

.SHORT TERM...(This Evening through Sunday)
Issued at 320 PM EST Sat Feb 24 2018

Last system for a few days rapidly approaching the area with one
more round of rain for the area, along with a few thunderstorms
and some windy conditions late tonight into Sunday.

Area of rain and embedded storms was working northeast with
leading edge pushing into SW Illinois, just a touch ahead of Hi
res models. Bulk of thunder has been with line of storms moving
through Arkansas and points east where the severe threat should
remain. More hit and miss lightning strikes further north. Looks
like 2 waves of precip, separated by only a few hours. Noted area
will push in to SW areas by 00Z and quickly overspread the area
within a few hours. A brief lull may occur in the wake of this
before the actual cold front arrives with a quick round of showers
and isolated storms. Upstream observations showing rainfall not
overly heavy as expected with fast moving nature helping keep
overall totals down. As a result rain amounts have been adjusted
down somewhat, but still sufficient to cause some issues in the
SE. Any storms could cause locally higher amounts in spots. Flood
watch will remain in effect, but may be able to be cancelled prior
to 12Z Sun. With surge of warmer temperatures will be seen by
many areas this evening as warm sector of the system quickly
pushes in and right with colder temps overnight.

Gusty winds will occur near and behind the cold front as fairly
strong wind field advances through. Some potential for gusts in
the 40 mph range (isolated 45 mph) that could cause some minor
tree damage with saturated ground and weakened hold by roots. Will
defer to eve/overnight shift to monitor wind trends for any
potential headlines. Consensus of offices was to hold off on wind
advisory given short nature of the strongest winds.

Sunday will end up dry with a good deal of sun by afternoon. Cold
air will be limited, if not in existence resulting in temperatures
similar if not somewhat warmer than today, starting the warming
trend that will be discussed in the long term.

&&

.LONG TERM...(Sunday Night through Saturday)
Issued at 320 PM EST Sat Feb 24 2018

Increasing upper level heights will not only keep rain at bay but
also allow for a nice warm up for the region with highs soaring well
into the 50s Mon-Weds as strong southwesterly flow sets up. Could be
some light showers Wednesday afternoon, but main chance for rain
will come as a result of 2 features, a weaker northern stream wave
and initially closed low over the SW states Tuesday. GFS/ECMWF
have been at odds with handling of the phasing with GFS more
aggressive and faster vs slow EC. However, 12Z EC appears to be
have come around and now almost perfectly matches GFS with
stronger system coming into better agreement with GFS in regards to
key features. Likely to categorical pops still warranted mainly Weds
night as this feature passes through. Could see a quick quarter to
half inch of rain (maybe more?) with progressive nature hopefully
keeping impacts to a minimum.

Return to colder, more seasonable temperatures will occur the
remainder of the period with even some limited lake effect potential
Thurs into Fri. Will keep slgt chc to chc pops as is for now.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1255 PM EST Sat Feb 24 2018

The active TAF period continues, but with quieter conditions at
the end.

At SBN, rain likely holds off for the next few hours before rain
showers and IFR ceilings arrive as a moisture-rich area of low
pressure lifts into the Midwest. Moderate to steady rain spreads
over the terminal near 00z with a further decrease in ceilings.
Wind shear becomes a concern as an intense low-level jet moves in.
Overnight, winds will quickly become west-southwesterly as a cold
front sweeps through.

AT FWA, there is the greater opportunity for passing rain showers
through the afternoon with continued IFR ceilings. As eluded to
in the previous discussion, thunder was added to the TAF. I could
see future TAFs further zeroing- in on this thunder threat. For
now, 00-07Z looks to be the best window of opportunity. LIFR
conditions are likely for a time during this period as well.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch through Sunday morning for INZ026-027-032>034.

MI...NONE.
OH...Flood Watch through Sunday morning for OHZ016-024-025.

LM...Small Craft Advisory from 7 PM this evening to 4 AM EST Sunday
     for LMZ043-046.

     Gale Warning from 4 AM to 4 PM EST Sunday for LMZ043-046.

&&

$$

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


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