Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 141012
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
612 AM EDT Sat Oct 14 2017

.SYNOPSIS...
Issued at 547 AM EDT Sat Oct 14 2017

Expect showers and thunderstorms near Lake Michigan today. Heavy
rain will be the main threat, with a flood watch in effect for
portions of southwest Lower Michigan. Isolated stronger storms
could develop late this afternoon and early this evening west of
US 31, along and north of the toll road. The main threat in these
storms, and even in heavier rain showers, would be gusty winds.
Otherwise, areas farther southeast will be primarily dry today,
with increasing clouds. The front will strengthen and move
southeastward later tonight into Sunday, bringing windy conditions
and chances for rain to the rest of the forecast area. Highs
today will be in the 70`s. Lows tonight will be in the 60`s.

&&

.SHORT TERM...(Today through Sunday)
Issued at 215 AM EDT Sat Oct 14 2017

One more day of unseasonable warmth before reality checks Sunday in
advance of potent nrn Rockies sw trough ejecting up through the nrn
lakes. Sfc boundary laid out this morning extending from srn MI swwd
into cntrl KS invof of developing sfc cyclone and likely to move
little today given future mesoscale outflow augmentation. Thus this
should serve as demarcation line for higher bound pops along and
north with little to nothing south as broadening warm sector is slow
to moisten/destabilize and forcing lines up well west. However will
hesitantly hold though with some ewd bend of slight chance mention
this aftn into cntrl zones to account for sporadic highres model
based projection of ewd extent of a potential weakening convective
cluster.

Otherwise low level baroclinic zone forcing mechanism expected to
pull nwwd in response to deepening sfc cyclone lifting through srn
WI overnight which should allow more focused precip to retreat well
north into MI/WI. Ewd surge of cold front should spurn another
frontal based circulation induced band of showers into wrn zones
late before decaying ewd into wrn OH Sun morning. Thereafter sharp
low level cold advection overspreads the cwa with strong w-nw winds
and falling aftn temps.

&&

.LONG TERM...(Sunday Night through Friday)
Issued at 215 AM EDT Sat Oct 14 2017

Sfc ridge builds quickly sewd through the OH/TN valley into Mon.
Newd extent of sfc ridgeline within low level thermal trough again
suggests some frost potential contingent on extent/duration of
decaying lake induced stratus and no doubt indicated in wide ranging
mos guidance temps Sun night. Best potential given climo would be
northeast and southwest.

Pattern aloft flattens thereafter with broad high latitude wrly flow
developing across the Conus through mid period before buckling late
week. Building low level thermal ridge into the lakes/OH valley
strongly suggest mos based guidance too heavily influenced toward
climo as H85 based thermal anomalies suggest 70s again likely Thu-
Sat.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 547 AM EDT Sat Oct 14 2017

The first batch of showers and thunderstorms along a cold front
stalled in the northwest arrived at KSBN at approximately 10Z.
Showers and thunderstorms will continue through the early morning
hours before taking a break early this afternoon, and expect to
see intermittent drops from VFR/MVFR to IFR through about 15z as
a result. KFWA will remain dry and VFR throughout this timeframe.
Additional showers and thunderstorms are possible at KSBN
throughout the afternoon and early evening, with the threat of
gusty winds and heavy rain. Hi-res guidance is inconsistent with
this secondary batch of precipitation, with some models even
keeping it further northwest of the terminal. Have included mainly
MVFR VIS with -SHRA VCTS for KSBN at this point given uncertainties,
but IFR is a possibility if the heavier showers and storms make
it far enough southast.

Otherwise, the main frontal passage will carry precipitation
through both terminals Sunday morning, with winds picking up late
tonight as they veer from southwest to northwest behind the front.
Wind shear is possible at both sites late once the stronger upper
level winds arrive, mainly after 5z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...Flood Watch through this evening for MIZ077-078.

OH...NONE.
LM...Gale Warning from 11 PM this evening to 8 PM EDT Sunday for
     LMZ043-046.

&&

$$

SYNOPSIS...MCD
SHORT TERM...T
LONG TERM...T
AVIATION...MCD


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