Area Forecast Discussion
Issued by NWS Northern Indiana

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422
FXUS63 KIWX 230641
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
141 AM EST Fri Feb 23 2018

.SYNOPSIS...
Issued at 140 AM EST Fri Feb 23 2018

Widespread significant flooding will continue over northwest
Indiana and southwest lower Michigan with record crests expected
on several rivers. For the remainder of the overnight, light rain
will return late and continue into Friday morning before drying
out for the afternoon. Only light rainfall amounts are expected.
Temperatures will slowly rise into the upper 30s and lower 40s for
the remainder of the overnight. Additional rain chances will
arrive Saturday into Saturday night.

&&

.SHORT TERM...(This Evening through Friday)
Issued at 309 PM EST Thu Feb 22 2018

Flooding concerns remain front and center for the next several
days as rivers across the area are in various states of flood and
forecasted rainfall causing lots of angst (and rightfully so)
regarding impacts on the rivers.

Somewhat drier air has overspread the area for the moment, with
the first of 2 surges of increased moisture and rain chances
arriving late tonight into Friday. Area of interest showing up
nicely on regional radars from east Kansas to NW Arkansas, moving
northeast to arrive in SW areas sometime after 6Z Fri and then
rapidly spread NE from there. Models varying to some extent on
exact precip amounts, but do seem to still agree on heaviest
remaining either in our far SE counties or possible away from the
area. NAM is most aggressive with QPF with others more subdued.
generally looking at a tenth of an inch NW to third of an inch SE
with this system, which should do little to the overall trends in
rivers.

Trend continues to show slightly warmer lows and smaller area of
limited concern for freezing precip late tonight into early Friday
as temps will hover near freezing and could rise above by the time
the rain arrives. Have left a token slgt chc/chc freezing rain in
far NE with eve/overnight shift to monitor.

&&

.LONG TERM...(Friday Night through Thursday)
Issued at 309 PM EST Thu Feb 22 2018

The majority of Friday night will end up dry before concerns
increase for additional rainfall that could bring some impacts to
local rivers. Majority of models keep heaviest rainfall Saturday
into Sat night mainly SE of the area (ECMWF) or splitting the area
(GFS). NAM has a more concerning trend with more NW push of
precip, especially Sat afternoon into Sat night with run total QPF
ranging from 0.75 inches NW to over an inch and a half central/SE.
Depending how fast the precip arrives could be a mix of rain/snow
on northern fringe of precip late Fri ngt into Sat AM before warm
air overtakes the area. Current river forecasts go with more
subdued solutions resulting in very slow trends in all rivers vs
rapid jumps or changes. If NAM were to work out, could be more in
the way of impacts. Will update ESF to address concerns and
continue to monitor.

Frontal boundary will surge across by Sunday morning, pushing the
rain out of the area and giving a much needed period of drying as
well as above normal temperatures. Next system may begin to arrive
by mid week, but only slgt chc/chc pops warranted at this time.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 125 AM EST Fri Feb 23 2018

Fairly strong warm/moist advection continues overnight into Friday
morning with deteriorating cigs to lower end IFR or LIFR. A low
amplitude short wave tracking across the western Great Lakes will
eventually allow for more veered southwesterly low level flow
taking deeper moisture axis across central Ohio. Precipitation to
this point has been mainly in the form of drizzle, but a window
from 10Z-15Z looks most favorable for deeper moisture profiles in
place as low level trough moves through to support a period of
light rain at terminals, possibly ending as a period of drizzle as
strong mid level dry air advection punches in. Cigs should
temporarily improve later Friday afternoon/evening, but another
advective moisture surge toward the end of the period will cause
cigs to deteriorate once again for late Friday night/Saturday with
renewed rain chances. The other issue for the remainder of the
overnight hours will potential of some patchy fog given shallow
moist airmass.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...Flash Flood Watch until 1 PM EST this afternoon for MIZ077.

OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...Marsili
SHORT TERM...Fisher
LONG TERM...Fisher
AVIATION...Marsili


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