Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 181125
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
624 AM EST Sat Nov 18 2017

.SYNOPSIS...
Issued at 113 AM EST Sat Nov 18 2017

Low pressure over central Kansas early this morning will deepen
rapidly as it streaks northeast into northern Ohio by evening.
Expect widespread rain and thunder at times south of highway 30.
Early day highs will range from the upper 40s northwest to the upper
50s southeast with falling afternoon temperatures as strong
northwest winds develop.

Thereafter a seasonably cool and dry week follows through
Thanksgiving.

&&

.SHORT TERM...(Today and Tonight)
Issued at 239 AM EST Sat Nov 18 2017

00Z RAOBS indicating strong kinematics associated with upper
trough extending through the CONUS. 160kt upper jet max ejecting
out of the four corners along with 75kt mid-trop speed max over
the southern plains aiding in continued deepening of surface low
over KS/MO border...06Z obs indicating 3hr pressure tendencies of
-2 to -3mb. VAD wind profiles ahead of low indicating 60-65kt LLJ
 which will aid in large scale moisture transport into the region
 today as PWs of 1.00-1.25 inches expected. Regional radars
 indicating precip re-development underway across central IL/IN
 and will overspread the entire forecast area this morning. While low
 level inversion associated with strong WAA will preclude any
 surface based convection...forecast soundings do indicate some
 limited elevated instability...CAPES generally 250-500J/kg...to
 support embedded thunderstorms within the precip shield. Warm
 cloud depths up to 10Kft decent for this time of year in support
 of heavy rain within the convective elements. Surface low to
 track NE through southern CWA this afternoon and move up into the
 eastern great lakes tonight. Strong gradient behind the front
 will have windy conditions tonight with small window of 30kt+
 gusts but not expecting advisory criteria at this time. Lake
 effect potential now looking even less impressive with lower
 inversion heights and delta-T.

&&

.LONG TERM...(Sunday through Friday)
Issued at 239 AM EST Sat Nov 18 2017

Mainly quiet weather pattern for the long term period. High
pressure building into the TN valley will have winds backing
around to a more westerly direction and bring an end to any
remaining lake effect Sunday morning. Northern stream system
moving across southern Ontario Tuesday will bring a cold front
through the area but high pressure remains anchored in the western
Atlantic just off the Carolina coast and blocking any return flow
to support any precip chances. NW flow behind the front but LES
parameters marginal at best and would bring little more than
flurries Wednesday so will continue with dry forecast. High
pressure builds back into the area to end the period bringing a
cool but pleasant Thanksgiving.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 624 AM EST Sat Nov 18 2017

Sfc low pressure had advanced into wrn MO as of 10Z and will lift
rapidly newd to just south of the FWA terminal by 18Z. Leading w-e
band of +shra and embedded thunder will hold south near term but
rapid upstream development/expansion noted ongoing through wrn/cntrl
IL in region of ramping upper jet coupling across tightening low
level baroclinic zone. Expect the leading edge of this activity will
be into the KFWA vcnty by 14Z as orginally thought.

Thus generally LIFR on the cold side of the boundary and IFR in the
warm sector. Post frontal cold advection wedge will wrap in quickly
as the low passes this afternoon with deformation band stratiform
rain ending this evening with improvement into MVFR toward 00Z for
both terminals. Otherwise sfc gusts to 30kts likely mid aftn into
early evening as intense sfc low exits newd.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 3 AM EST early this morning for
     LMZ043-046.

     Gale Warning from 10 AM this morning to 4 AM EST Sunday for
     LMZ043-046.

&&

$$

SYNOPSIS...T
SHORT TERM...JAL
LONG TERM...JAL
AVIATION...T


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