Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 180742
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
242 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 06Z TAFS through 06Z Saturday Night)
Issued at 1153 PM EST Fri Nov 17 2017

Low pressure near Wichita KS will deepen rapidly near term as it
rockets newd into wrn lake erie by this evening. KFWA terminal falls
on warm side of this system with primary IFR conditions taking hold
after 10Z. KSBN on the other hand primarily LIFR for much of the day.

Lead arc of rain along nose of low level theta-e surge on the way
out through wrn OH. However jet coupling aloft in advance of sfc
cyclone approach will drive intense frontal scale circulations both
along the warm front later this morning and again by late
morning/early aftn along the cold front. Will add a tempo tsra
grouping at KFWA given proximity to triple point junction otherwise
KSBN looks to be too deep within cold conveyor for a thunder risk.
Otherwise periods of moderate to heavy rain with inherent variable
vsby/cig reduction likely.

Otherwise window of intense nwrly sfc gusts to 30 knots expected
this aftn within strong low level cold advection burst.


&&

.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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