Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 202003

Area Forecast Discussion
National Weather Service Northern Indiana
303 PM EST Mon Feb 20 2017

Issued at 130 PM EST Mon Feb 20 2017

Unseasonably mild conditions will continue through Friday. Dry
weather will persist through this evening, but an upper level
disturbance and frontal boundary will provide a likelihood of
light rain showers late tonight into Tuesday. Mainly dry weather
is then expected for Tuesday night through Wednesday night before
rain chances increase once again by Thursday, and especially on
Friday as a stronger storm system approaches. There is a risk of
some severe weather on Friday with strong winds as the main
threat. The warmest conditions of the forecast period are expected
on Wednesday when highs are expected to range from the mid 60s to
70. Temperatures will drop back to near seasonable normals by the
upcoming weekend with a chance of snow showers Saturday.


.SHORT TERM...(This Evening through Tuesday)
Issued at 300 PM EST Mon Feb 20 2017

A significant part of the upper level trof will shear out northeast
into Ontario Province in Canada, leaving an upper level low well to
the south over the Gulf Coast States. This will leave somewhat of a
gap of upper air support over the forecast area tonight. Have
reduced rain chances tonight. Rainfall amounts should be light.
Very little cold air will be behind this system, so the warm
pattern will continue with highs in the 60s Tuesday.


.LONG TERM...(Tuesday Night through Monday)
Issued at 300 PM EST Mon Feb 20 2017

The unseasonably mild pattern will persist through Friday with highs
in the 60s each day; even nearing 70 Wednesday. Record highs
Wednesday are 66 at South Bend and 67 at Fort Wayne respectively.  A
strong upper level system and accompanied deep low pressure area
will move into the western Great Lakes region and bring a round of
showers and storms Friday. The Storm Prediction Center has expanded
their severe storm risk for Friday and have included all of the
forecast area. An upper level speed max combined the advection of an
elevated mixed layer will favor severe storms as a cold front
approaches. Kept thunder in Thursday night and Friday. Temperatures
should still be mild into Friday, but then turn much colder
Saturday, although temperatures will still be close to normal for
this time of year with highs in the mid 30s to mid 40s. A rain,
snow and/or rain/snow mix is possible from late Friday night
through Monday, but little if any snow accumulation is expected.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 130 PM EST Mon Feb 20 2017

Southeast winds will continue to slowly ramp up this afternoon as
some shallow mixing develops after this morning`s strong low
level inversion. Strongest gradient across NW/portions of NC
Indiana should support strongest gusts around 20 knots at KSBN
this afternoon. An upper level short wave will lift east-northeast
across the western Great Lakes tonight allowing weak cold frontal
boundary to push into the area. Did maintain prevailing showers
following progression of this front late tonight/early Tuesday
morning but general weakening of upstream disturbance and weak
nature to the front could limit extent/duration of rain showers
to some degree. Did trend to mainly lower end MVFR conditions at
KSBN late tonight/early Tuesday morning with better pre-frontal
moisture push, with a brief period of IFR cigs not out of the
question. Moderate low level jet of around 40 knots will develop
tonight that could pose LLWS threat toward 12Z, but given marginal
nature and strong sfc gradient will hold off on mention.


LM...Small Craft Advisory until 4 AM EST Tuesday for LMZ043-046.



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

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