Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250428
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1228 AM EDT Wed MAY 25 2016

.UPDATE...
The Near Term Section has been updated below.

&&

.SYNOPSIS...
Issued at 231 PM EDT Tue May 24 2016

Upper waves will interact with an increasingly moist and unstable
atmosphere to produce daily chances for showers and thunderstorms
through the next week. Temperatures will remain above average
through the period.

&&

.NEAR TERM.../Overnight/
Issued at 1228 AM EDT Wed May 25 2016

Pulled pops through 07z and lowered them to slight chance the rest
of the night based on radar trends and as the HRRR reflectivity
progs have been overforecasting convection tonight so far.

Previous discussion follows...

Showers and thunderstorms from the first wave have dissipated,
leaving perhaps a few sprinkles in the far southwest forecast area.
Not much convection left in southern Illinois either.

However, Rapid Refresh model still indicates low chances for
convection overnight. Given this, and with another upper wave still
moving in tonight, am not ready to go dry even with little
convection upstream. Did lower PoPs some and delayed them over much
of the area until overnight. Removed thunder from this evening
(based on what`s out there now) but kept isolated mention overnight.

Adjusted cloud cover as necessary with some decent cloud cover
south. This required some minor adjustments of low temperatures as
well.

Previous discussion follows...


One upper wave was slowly moving toward the southwest forecast area
this afternoon. This wave has been producing a few showers. More
widespread showers and storms were across Missouri with another
wave, but these are moving south of east toward better instability.

The atmosphere across the area remains relatively dry, and it will
take a while for it to moisten up.

Went slight chance PoPs this evening over southwest portions of the
area with the first wave moving into the area with weak forcing and
limited moisture.

Overnight increased PoPs into low end chance category most locations
as the next wave moves in. Forcing is not that great and
instability will be low.

Generally stayed close to MOS for low temperatures.

&&

.SHORT TERM.../Wednesday through Friday/
Issued at 231 PM EDT Tue May 24 2016

Focus remains on chances for rain through the period. Models are
similar with the big picture but, as has been the case, differ on
the details of upper waves and resultant rain chances. Confidence is
lower in these setups, so stayed close to a blend.

With the lower confidence in timing and location of upper waves,
went chance PoPs most area throughout the short term. Northern areas
might see better chances for rain Wednesday night as a warm front
passes to the northwest.

Warm advection will allow temperatures to climb into the lower and
middle 80s for highs during the period. A model blend reflects this
well. (Of course, temperatures may be affected by any advection that
does occur.)  Friday may be even warmer if the NAM pans out as it is
forecasting highs near 90.

&&

.LONG TERM /Friday Night through Tuesday/...

Issued at 155 PM EDT Tue May 24 2016

Warm and Humid pattern looks to remain in place during this period
as ECMWF suggests strong ridging remains in place across the East
Coast. This allows a warm and humid southerly flow to persist
through the period. Minimal support for precipitation will pass
across Indiana during the period as weak short waves aloft appear
to be unorganized and along with surface features which really
remain under the influence of High pressure. Although given
diurnal heating and the moist air mass in place...afternoon and
evening showers and storms cannot be ruled out.

Best chance for showers and storms looks to be on Saturday...as a
weak trough pushes through the upper flow in the upper midwest.
Indiana is not in the best position to benefit from the forcing
for precip...however ECMWF suggests a weakly negatively tilted
upper trough passing on Saturday. Thus expect highest pops through
the period on that day.

&&

.AVIATION /Discussion for 250300z TAF issuance/...

Issued at 1040 PM EDT Tue May 24 2016

Pushed back the timing on VCSH at KIND by a few hours. Previous
discussion follows...

Mainly VFR conditions through the period. Forecast soundings and
MOS guidance indicates some potential for MVFR fog late during the
overnight at KLAF so brought in 4SM 9-13z there. Elsewhere
increasing clouds should negate any fog development. Hi res models
are showing scattered showers developing around all sites but KLAF
around 4-6z so added in a VCSH during that time, but time heights
and upstream obs don`t show much in the way of restrictions so
kept VFR during that time. Looks like there could be a lull in
activity late morning before some scattered thunderstorms develop
in the afternoon. Kept a VCTS going starting around 20z at the
sites for this, but again with scattered storms and many places
missing out did not add any restrictions with it.

&&

.IND Watches/Warnings/Advisories...
NONE.
&&

$$

SYNOPSIS...50
NEAR TERM...50/MK
SHORT TERM...50
LONG TERM....PUMA
AVIATION...CP


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