Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 200616
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
216 AM EDT Sat May 20 2017

.SYNOPSIS...
Issued at 718 PM EDT Fri May 19 2017

Low pressure over the southern Plains will move slowly northeast
into the upper Great Lakes this weekend causing showers and
thunderstorms at times across our area through Sunday morning,
with best chances late Saturday afternoon and Saturday night as
the cold front associated with this system approaches. High
pressure will build into the area later in the day Sunday
providing dry weather which should then continue through Monday
night. Temperatures over the next few days will be near normal
for this time of year.

&&

.UPDATE...
Issued at 840 PM EDT Fri May 19 2017

Only sgfnt change made to grids this eve was to remove
thunderstorms from the fcst overnight. Sct showers and patchy
drizzle should continue behind departing wk shrtwv this eve but
ridging aloft should decrease mid level lapse rates and provide
some drying aloft this eve into early Saturday morning so tstm
chances have diminished. Shower/tstm pops ramp back up tomorrow
morning into aftn as stnry front moves north in response to low
pressure lifting ne out of the srn plains.

&&

.SHORT TERM...(This Evening through Saturday)
Issued at 410 PM EDT Fri May 19 2017

Minoring shortwave moving into west central Ohio amid piddling
250-500 j/kg MUCAPE to relegate lesser/coverage mention for TSRA
primarily to southeast CWA tiered by even lesser
probabilistic/slight chance mention per trends in pulse activity.
Otherwise little chance for convection overnight, initially far
south on northern periphery of richer theta-e, then to far
western/southwest CWA early morning as deep central Rockies
cyclone begins to liftout northeast into Plains. Further ramp of
pops/qpf through Saturday afternoon/night with increasing height
falls and approach of attendant frontal zone.

&&

.LONG TERM...(Saturday Night through Friday)
Issued at 410 PM EDT Fri May 19 2017

Slightly faster west to east end of shra/partial clearing on
Sunday per decent frontal timing agreement. Eschewed pop/sensible
weather mention again for Monday amid surface ridging into Lower
Ohio Valley. Secondary northern stream system digging in for
renewed shra/tsra chances by Tue, followed by Wed chc shra as
boundary layer stabilization anticipated amid more
occluded/stacked system, then yet another northern stream dig
about Thu night.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 158 AM EDT Sat May 20 2017

Terminals will remain north of the sfc boundary through this
period. Easterly flow will continue north of this boundary with
strongest winds today expected at KSBN due to a pocket of fairly
strong sfc pressure falls working across the western Great Lakes
later today. Continued strong low level inversion and easterly
flow should be conducive for maintenance of low clouds through
most of this period. Generally expecting cigs fairly close to
current levels to persist although some cigs closer to 1000 feet
cannot be ruled out. Stronger mid/upper level forcing will remain
west of the terminals today, although increasing isentropic ascent
today and approach of a few weaker embedded southwest flow short
waves should allow scattered showers/isolated thunderstorms to
affect northern Indiana late morning/afternoon. Confidence in
thunder is too low for inclusion at this time. Better chance of
scattered thunderstorms tonight as low level warm front begins to
approach northern Indiana with more robust instability and
eventual eastward migration of stronger upper forcing. At this
forecast distance, will keep thunder mention to VCTS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 4 PM EDT this afternoon for LMZ043-
     046.

&&

$$

UPDATE...JT
SYNOPSIS...JT
SHORT TERM...Murphy
LONG TERM...Murphy
AVIATION...Marsili


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