Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 191959
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
259 PM EST Sun Feb 19 2017

.SYNOPSIS...
Issued at 100 PM EST Sun Feb 19 2017

Unseasonably mild conditions will continue through much of the
upcoming week. Weak winds associated with a departing ridge of
high pressure will likely lead to fog formation once again
tonight, with a potential of some dense fog late tonight into
early Monday morning. Dry conditions will continue through Monday
afternoon, but rain will become likely Monday night into early
Tuesday. There is another chance of rain Wednesday night as a
system tracks north of the area, but the greater chance of showers
and a few thunderstorms is expected by Thursday night and Friday
as a stronger storm system takes shape across the middle of the
country. Wednesday is expected to be the warmest day of the week,
with highs reaching into the 65 to 70 degree range. Low
temperatures tonight will range from the mid 30s to lower 40s.
High temperatures on Monday will range from the mid to upper 60s
across northwest Indiana, to the mid to upper 50s across south
central lower Michigan.

&&

.SHORT TERM...(This Evening through Monday)
Issued at 254 PM EST Sun Feb 19 2017

Areas of fog were able to form in a shallow cold layer with
overnight radiation last night. There should be a similar situation
tonight with fog reforming over at least the southwest half of the
forecast area in light return flow. The HRRR appears to have a good
handle on this scenario. Otherwise, the mild pattern will continue
with lows tonight staying above freezing. Highs Monday should be in
the 60s, except possibly of over far northeast areas. Highs Monday
should be well above normal in the 60s again and approach the
records of 67 at Ft Wayne and 65 at South Bend.

&&

.LONG TERM...(Monday Night through Sunday)
Issued at 254 PM EST Sun Feb 19 2017

The unseasonably mild pattern will persist through most of the
upcoming week with highs well above normal as the long wave upper
trof persists over western North America. A leading short wave was
near the Four Corners area this afternoon and has moved out of the
main long wave trof. This system will move east and should reach the
forecast area Monday night and spread showers over the area into
Tuesday. The GFS and ECMWF are still in good agreement with the
timing of this system along with the Canadian GEM suggesting the
best chance for rain Monday night and early Tuesday. Otherwise,
there will be a little break in the rain Tuesday night and Wednesday
before a stronger system reaches the area Thursday and Friday. The
Storm Prediction Center has already placed part of the forecast area
in the Day 6 severe weather outlook. Several factors were coming
together for the chance for severe storms including the advection of
an elevated mixed layer. Kept thunder in Thursday night and Friday.
Temperatures should still be mild into Friday, but then turn much
colder Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 100 PM EST Sun Feb 19 2017

Fog and stratus have diminished across the terminals early this
afternoon with VFR conditions expected to persist through early
evening. Weak gradient associated with the ridge of high pressure
and large lake/land thermal differentials should support lake
breeze formation and eventual preference to west-northwest wind
directions at KSBN later this afternoon. Sfc ridge axis will
depart to the east tonight allowing for weak low level return flow
and some re-orientation of low level theta-e gradient which will
likely become positioned from southwest lower Michigan into
northwest Ohio overnight. Weak flow and very favorable moisture
profiles with height should support another night for fog
formation for both terminals. Given medium to higher confidence in
this scenario did trend terminals to IFR/LIFR vsbys in fog
overnight into early Monday morning. Conditions should begin to
improve after the 15-16Z timeframe Monday morning.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...Marsili
SHORT TERM...Skipper
LONG TERM...Skipper
AVIATION...Marsili


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