Area Forecast Discussion
Issued by NWS Northern Indiana

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533
FXUS63 KIWX 011823
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
223 PM EDT Sat Oct 1 2016

.SYNOPSIS...
Issued at 202 PM EDT Sat Oct 1 2016

A slow moving upper level disturbance will generate numerous rain
showers and a few thunderstorms into early tonight. Conditions
will gradually improve Sunday into Monday though as this low
pressure system exits the region. Dry weather expected by Monday
and Tuesday with temperatures near normal. Lows will be in the
50s the next several nights. Highs around 70 Sunday and Monday.

&&

.SHORT TERM...(Today and Tonight)
Issued at 310 AM EDT Sat Oct 1 2016

Cutoff upper low slowly inching northward this morning and is
expected to be directly overhead for most of the day today with
500mb heights remaining around 563 dam. Yet another surge of 295K
isentropic ascent and 850-700mb fgen associated with vorticity
spoke rotating north this morning. This is generating numerous
showers across our eastern counties at press time that will
continue to pivot westward through early morning. As previously
suspected, cold pool aloft (500mb temps below -20C) and surface
dewpoints near 60F supporting several thunderstorms even into the
late overnight period. Latest hi-res guidance indicates this
activity will continue through the early morning with a brief
break possible during the late morning/midday as vort max moves
directly overhead, cutting off CVA forcing. However, filtered
insolation, relatively moist low levels, and cold temps aloft will
lead to modest destabilization during the mid-late afternoon
(uncapped SBCAPEs of 300-500 J/kg) and a few showers/storms
expected to redevelop. Coverage somewhat in question (especially
in our east) given limited forcing and instability but will
maintain previous low-end likely PoP`s as most areas expected to
see a shower at some point. Precip will taper off this evening as
upper low finally begins to lift NE. Overnight period could end up
largely dry with building heights/AVA and increasing stability.
Did lower PoP`s (especially after 03Z) but hesitant to go
completely dry given lingering moisture/cyclonic flow.

Highs today will be similar to yesterday, though perhaps a few
degrees warmer in some spots. Generally cloudy conditions expected
but a few peaks of sun/thinning clouds not out of the question with
a few pockets of drier air being wrapped into the system. Forecast
soundings indicate enough diurnal mixing to support highs in the mid
to perhaps upper 60s. Lows tonight likely a few degrees cooler as
slightly drier air slowly works into the area on backside of
departing low.

&&

.LONG TERM...(Sunday through Friday)
Issued at 310 AM EDT Sat Oct 1 2016

Lingering moist/cyclonic flow will continue into Sunday and with the
added benefit of diurnal destabilization and relatively warm Great
Lakes, a few SCT showers may be possible, primarily during the
afternoon and mainly in our N/NE counties. Latest models now
indicating embedded shortwave will be a bit weaker and further NE
than indicated last night so will trim back PoP`s even further.
Still expect a fair amount of cu/stratocu on Sunday but more sun
anticipated and highs should make a run at 70F.

Upper low is finally shunted far enough NE Sunday night to allow
stout mid/upper level ridge to build across the Great Lakes,
downstream of deep western CONUS trough. This will result in fair
weather for the first half of the work week with highs building into
the upper 70s by Wednesday. Medium range deterministic models
continue to struggle with details of evolving pattern for late in
the week. Ejecting trough will eventually send a cold front through
our area but timing remains uncertain. Stuck close to previous
forecast highlighting Thurs/Thurs night with best chances for rain.
Cooler and drier conditions expect Fri and Sat.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 157 PM EDT Sat Oct 1 2016

A large upper low was just southwest of Ft Wayne early this
afternoon. Numerous showers and a few thunderstorms were
associated with this system. The upper low should accelerate
northeast with showers diminishing tonight. Kept conditions MVFR
to VFR tonight, although some pockets of IFR CIGs are possible.

&&

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

$$

SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Skipper


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