Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 180640
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
140 AM EST Mon Dec 18 2017

.SYNOPSIS...
Issued at 1254 AM EST Mon Dec 18 2017

Clouds with areas of fog and patchy drizzle will continue the rest
of the night. Temperatures will be steady or rise into the 40s by
daybreak. Drizzle should end and fog should lift by late morning
followed by afternoon highs approaching 50. For the rest of the
week, dry and mild conditions persist, until a front brings rain
on Friday. Much colder air will filter in behind the front for the
holiday weekend, along with the potential for lake effect snow.

&&

.UPDATE...
Issued at 926 PM EST Sun Dec 17 2017

Warm front has pushed north to near the IN/MI border and so have
moved time of areas of fog earlier by a few hours. Have also kept
highest pops for drizzle along front. Temperatures and dew points
also were adjusted higher to fit current obs and increased time
of arrival of higher Ts and Tds heading into Monday morning. Will
be monitoring for faster development of patchy dense fog by Monday
morning near current snow pack as well with faster advection of
higher dew points from the south.

&&

.SHORT TERM...(This Evening through Monday)
Issued at 414 PM EST Sun Dec 17 2017

Split flow pattern with splitting/minoring lead waves in advance of
stronger highly positive tilted northern stream wave to provide a
few very light rainfall events in near term. First minored wave to
orphan later this evening though southeast quarter followed by
several hour lull until leftmost vorticity split swept through
northwestern cwa amid deeper orphaned low level moisture column.
Stronger 925-850 mean layer flow on order of 25-30 kts across
northern tier CWA late tonight/Mon am should bode more favorable for
stratus formation/depth over br production and relegate fog mention
to no stronger than areas of br 10-15 UTC. Eastward sweep of trof
axis for dry conditions/higher ceilings and more veered/surface
based warm air advection flow to support temps a few degrees higher
over prior forecast, and inline with latest trend.

&&

.LONG TERM...(Monday Night through Sunday)
Issued at 414 PM EST Sun Dec 17 2017

Southern Baja/northern Mexico cyclone ejects and supports midweek
cyclogenesis tracked well south of CWA to afford a long duration
dry/mild period. Thereafter amplification of flow regime amid
western conus trof/130W ridge. Gradual eastward shift portends to
latter part of the week sern CO cyclogenesis for Dy6 rain event
followed by sharply colder air/lake effect event for holiday
weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1253 AM EST Mon Dec 18 2017

A mild and moist airmass will continue to spread north over the
area and be accompanied by areas of drizzle and patchy fog.
Lingering snow cover at SBN will help accentuate fog development.
Given the moisture flux into the area, IFR conditions may not
improve until this afternoon. The break in the lower clouds may be
brief as moisture continues to spread northeast ahead of a weak
front. For now, have kept VFR conditions at SBN later this
afternoon into this evening, but not entirely confident that the
lower clouds will scatter out.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory from 4 PM this afternoon to 4 PM EST
     Tuesday for LMZ043-046.

&&

$$

UPDATE...Roller/Skipper
SYNOPSIS...Murphy
SHORT TERM...Murphy
LONG TERM...Murphy
AVIATION...Skipper


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