Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Indianapolis in
425 PM EDT Thursday Apr 24 2014

Update...
the aviation section has been updated below.

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Synopsis...
issued at 309 PM EDT Thursday Apr 24 2014

A cold front will move through the area tonight...bringing
widespread showers and chances for thunderstorms to the area.
Relatively quiet and pleasant weather will persist from late Friday
into the latter part of the weekend...then a low pressure system
will cut off and begin slowly spinning through the area...making for
a prolonged period of unsettled weather throughout next week.

&&

Near term /rest of this afternoon through tonight/...

Issued at 309 PM EDT Thursday Apr 24 2014

The timing for the beginning of the cold frontal passage still
appears to be later this evening. So for the rest of this
afternoon the weather will be dry but low to middle level clouds will
be on the increase. Have lowered high temperatures even more for
this afternoon based on observations these past few hours. Widespread
highs only in the middle to upper 60s appears attainable.

The front is projected to reach the area closer to midnight with
the bulk of the precipitation and chance for thunderstorms. Better
chances lie across the southern counties where the best lift and
instability is. Feel confident enough to raise all probability of precipitation to 100
percent overnight and appears this will be a decent soaker with at
least around half an inch possible most locations. Went slightly
above MOS for highs 50-56 considering all the clouds and rain.

&&

Short term /Friday through Sunday/...

Issued at 309 PM EDT Thursday Apr 24 2014

The front will be exiting during the morning hours Friday with
the highest chances across the eastern counties at 12z and dry
across the western counties. By noon most the forecast area should
be dry. Went slightly below MOS to account for weak cold air
advection for highs in the middle 60s to around 70.

The remainder of the period will be relatively pleasant with dry and
mostly clear to partly cloudy skies dominating the period and climatology
temperatures. Another system will begin to approach the region late in the
period on Sunday. For now have indicated slight chance for
scattered showers Sunday afternoon.

&&

Long term /Sunday night through Thursday/...

Issued at 243 PM EDT Thursday Apr 24 2014

A large upper low will move slowly east from the plains through the
extended period bringing unsettled weather to central Indiana. Rain
is in the forecast throughout the period as well as small
thunderstorm chances from Sunday night through Tuesday. In addition
to the upper low...it looks like a front could be near the forecast
area through much of the extended...although exactly where it sets
up still has a decent bit of variability in the models. Skies should
remain mostly cloudy for the most part through the extended under
the influence of the upper low...but temperatures could remain near
to slightly above normal if the warm front sets up to the north and
remains there. Current solutions bring cold air in as the stacked
low sets up over the Great Lakes so expect below normal temperatures
near the end of the period.

&&

Aviation /discussion for 242100z ind taf update/...

Issued at 425 PM EDT Thursday Apr 24 2014

No changes needed to the taf.

Previous discussion follows...

Wind gusts of 20-25 kts out of the southwest will continue through
the rest of the afternoon but drop off after around 0-2z. Clouds
will increase this evening and overnight but expect VFR conditions
to remain until the arrival of rain ahead of the cold
front...which should overspread the sites from 5-7z. Expect mainly
MVFR ceilings and visibilities with the rain. Cold frontal
passage will then occur from around 11-14z with winds veering
around to the northwest and gusts picking up again...this time in
the 25-30 knots range out of 310-340 and these should continue
through the rest of the day Friday. Rain should come to an end
within an hour or two of frontal passage. There will be some
instability available ahead of the front so will continue to
mention thunderstorms in the vicinity during the showers for all but klaf.



&&

Ind watches/warnings/advisories...
none.
&&

$$

Synopsis...smf
near term...smf
short term...smf
long term....cp
aviation...cp/mk

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