Area Forecast Discussion
Issued by NWS Northern Indiana

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760
FXUS63 KIWX 190926
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
426 AM EST Mon Feb 19 2018

.SYNOPSIS...
Issued at 344 AM EST Mon Feb 19 2018

Very wet and mild weather can be expected into Wednesday. Highs
will rise into the 50s to around 60 today, and then from 65 to 70
Tuesday. Periods of rain with an occasional rumble of thunder will
persist through Tuesday night. In addition to flooding on rivers,
areal flooding is likely, particularly over low lying and other
flood prone areas.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 342 AM EST Mon Feb 19 2018

The first round of rain has already arrived early this morning as
moisture had surged northeast with many rainfall amounts already
between 0.15" and 0.40" south and west of Warsaw by 4 am EST.
Periods of rain into Wednesday will cause hydrologic issues with
general amounts between 2 and 4 inches. Higher amounts are
possible where convective bands will likely produce more than 4
inches by late Wednesday. Several factors continue to be very
supportive for moderate to occasionally heavy rain for an extended
period. Precipitable water values per latest GFS will rise above
1.3 inches at times which would top the climatological values for
this time of year. NAEFS/ensemble mean precip water forecast
values exceed the 99.5% percentile/climate into Wednesday,
indicative of the potential for an extreme event. As mentioned
yesterday, an analog from Feb 29 to March 5 of 1976 produced 5.45
inches of rain at South Bend. WPC is supportive of of heavy
rainfall with widespread amounts by late Wednesday between 2 and 4
inches. After coordination with surrounding offices, have issued a
flood watch to highlight flooding concerns associated with these
rainfall amounts. There is a good chance highs Tuesday will set
records at both South Bend (current record 65) and Ft Wayne (67).

&&

.LONG TERM...(Wednesday night through Sunday)
Issued at 426 AM EST Mon Feb 19 2018

Much colder air will spread across the area Wednesday behind a
strong cold front. Light snow accumulations are possible along
with water on pavement freezing Wednesday night setting the stage
for potential travel issues. Highs will recover into the 40s
Thursday, so any travel issues should end by late morning. More
rain is likely Friday/Saturday which will likely aggravate
ongoing flooding issues.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1230 AM EST Mon Feb 19 2018

Rapid development of precipitation currently taking place over
north central IL and a little north of most recent hires model
guidance. Should continue to see rapid development and eastward
expansion overnight with strong low level jet and moisture
convergence. Deteriorating flight conditions expected overnight as
rain moves into terminals and low levels saturate. Rain and
increased low level dewpoints over cold snowpack will likely lead
to another period of IFR and possibly LIFR fog impacting
primarily KSBN where 5+ inches of snow remain on ground. Have
trended KSBN TAF down significantly. Other significant issue will
be wind shear. Impressive low level jet of 70+ knots expected to
persist through entire period and likely beyond. Carried low level
wind shear through entire period even with mixing given strength
of this jet.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch from noon EST /11 AM CST/ today through Wednesday
     afternoon for INZ003>009-012>018-020-022>027-032>034.

MI...Flood Watch from noon EST today through Wednesday afternoon for
     MIZ077>081.

OH...Flood Watch from noon EST today through Wednesday afternoon for
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...Skipper
SHORT TERM...Skipper
LONG TERM...Skipper
AVIATION...Lashley


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