Area Forecast Discussion
Issued by NWS Northern Indiana

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037
FXUS63 KIWX 300204
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
904 PM EST Tue Nov 29 2016

.SYNOPSIS...
Issued at 338 PM EST Tue Nov 29 2016

There is a chance of showers tonight into Wednesday as a
disturbance rotates northeast into the region. Otherwise, dry
conditions are expected for most areas. Lows overnight will only
drop back into the 40s and highs on Wednesday will range from the
upper 40s over northwest Indiana to the middle 50s in northwest
Ohio. More seasonably cooler air will infiltrate later this week
with highs around 40 and lows around 30. With the cooler air there
is a chance of some lake effect rain and snow showers north of
highway 6 but little or no snow accumulation is expected at this
time.

&&

.UPDATE...
Issued at 900 PM EST Tue Nov 29 2016

Shrtwv and nw-se oriented sfc trof/psuedo warm front producing sct
showers as it moves across nrn portions of the cwa this eve. This
convection should lift ne out of our area in the hour or two.
Moisture return ahead of slowly apchg upr level trof/sfc cdfnt
should mainly be confined to areas to our east but showers may
develop overnight across ern portion of the cwa as previously fcst.
Just minor changes needed to previous pop grids to reflect ongoing
trends.

&&

.SHORT TERM...(This Evening through Wednesday)
Issued at 338 PM EST Tue Nov 29 2016

Minor changes to forecast with regards to weak disturbance and push
of higher theta-e into the area. Elevated instability already
advecting in with vis sat showing accas into NW Indiana as well as
back into portions of N/Central Illinois. KLOT/KIWX radars are
showing an increase in returns with surface observations suggesting
dry column remains in place at low levels with no precip reported at
present and temp/dewpt depressions in the teens. As moisture
continues to arrive, this dry layer should be overcome allowing for
a chance of precip to reach the ground in mainly NW areas. Although
instability is depicted, have removed mention of thunder (as has
surrounding offices) due to lack of confidence/short duration of
potential. Across the entire area, clouds will continue to develop
and increase tonight into Wednesday as the wave shifts east and
interacts with better moisture east of the area where the bulk of
the rain will set up. However, some light rain may edge into SE
areas later tonight into Weds warranting slight chance to chance
pops.

Deep upper low will send a strong wave into the region late Weds
into the long term period, bringing an end to our above normal temps
and continuing a unsettled pattern. Highs will still reach the upper
40s NW to the middle 50s SE as the coldest air arrives in the
afternoon and spreads east.

 &&

&&

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 338 PM EST Tue Nov 29 2016

Effects of first of 2 significant waves will be underway across the
area with increasing SW flow and low level moisture setting stage
for lake enhanced rain/snow showers. Greatest chances will reside
across portions of N Berrien into Cass counties Weds evening. Have
increased pops somewhat above blends, but kept shy of likely with
best forcing and omega plumes residing north of the area. Showers
will be possible further south in the evening until the wave passes.
Additional waves will quickly follow and allow flow to become more
westerly warranting holding with chc pops into Friday. Thermal
profiles won`t be clear cut with regards to 1 ptype or another much
of the period so have generally left a mix in for the moment.

Med range models continue to vary on handling longwave trough
currently over the Eastern Pacific set to move into the SW
states.Have held onto chc pops Sunday into Sunday evening as wave
separates from digging trough and moves quickly east. Eventually
additional energy will round the trough and move NE. ECMWF remains
the strongest and furthest west with this feature vs GFS that
entrenches the area in high pressure and forces the energy well
east. Have left chc pops Monday night into Tuesday with plenty of
time to see how this sets up.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 616 PM EST Tue Nov 29 2016

Vort max lifting ne ahead of main upr trof over the plains will
cause sct -shra across the area this eve. Dry low levels in place
will result in most of the rain evaporating before reaching the
ground so just fcst VCSH in tafs. Cdfnt associated with plains upr
trof will move slowly east across nrn IN late tonight and Wed
morning. Low level moisture advection/convergence associated with
the cdfnt should result in some stratus/br developing as the
front moves through. Low clouds should sct out for awhile Wed
after fropa, before wrap around moisture spreads low vfr cigs
back into the area from the west toward eve.


&&

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

$$

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


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