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Area forecast discussion 
National Weather Service Indianapolis in
620 am EDT Tuesday may 5 2015


The aviation section has been updated below.


issued at 400 am EDT Tuesday may 5 2015

Frontal zone across the northern portions of the forecast area will
lift slowly northward today...although may remain close enough for a
few thunderstorms over far northern portions of central Indiana. The
frontal zone will gradually weaken and upper level ridging will
dominate the area middle week before another frontal system pushes into
the area bringing thunderstorm chances back to the forecast for the


Near term /today/...
issued at 400 am EDT Tuesday may 5 2015

Combined frontal zone/residual outflow boundary is in place across
northern forecast area...and lifting slowly northward as upper
disturbance pushes to the northeast. Frontal zone may remain close
enough to the northern forecast area to spark a few additional
thunderstorms...mainly this afternoon. Thus will carry probability of precipitation across
the far northern portions of the area from late morning on.

Recent trends suggest consensus temperature numbers are just slightly low.
Expect the 80 degree mark to be reached across the majority of the
area today.


Short term /tonight through Thursday night/...
issued at 400 am EDT Tuesday may 5 2015

Although convective temperatures should be reachable each
afternoon...and low level lapse rates are fairly steep...middle level
lapse rates are significantly less supportive of convection in the
absence of significant upper level support. Will continue with a dry
forecast through Thursday night as a result.

Consensus temperatures appear a bit low each day on maximum temperatures...and
reasonable on min temperatures.


Long term /Friday through Monday/...
issued at 342 am EDT Tuesday may 5 2015

Warm and stormy extended is in the cards as upper ridge...currently
over the southern states and Ohio Valley shifts to the eastern coast
and Atlantic...and a strong upper Southern California low lifts
northeast leaving central Indiana in southwest flow aloft. The upper
low will spin up a surface low. The 00z European model (ecmwf) and Gem and the European model (ecmwf)
ensemble means are further northeast with this feature by 00z Monday
as they take it to western Iowa. The GFS and its ensemble means had
it well southwest and stronger over northwestern Kansas at that
time. Favor a European model (ecmwf)...ecens and Gem blend which kicky slides the low
east across the Great Lakes and an associated cold front southeast
across central Indiana Monday night.

At any rate...all models bring southerly flow off the Gulf to the
Ohio Valley throughout the extended ahead of the previously
mentioned low pressure system. This will continue to bring
warm...moist and unstable air to central Indiana. Various upper
waves in the southwest flow and later the approaching frontal
system...suggest regional blend looks good with thunderstorm chances
each period.

Regional blend temperatures look good with afternoon highs in the
upper 70s to middle 80s. Overnight lows should only drop to the


Aviation /discussion for 051200z taf issuance/...
issued at 620 am EDT Tuesday may 5 2015

Quasi-stationary front...just south of laf...should move north of
there near or shortly after issuance time. Think the MVFR fog will
lift by 12z. Otherwise...would not rule out a thunderstorm or two
this afternoon at laf...being closer to the front.
However...confidence too low to mention in the taf. Confident that
VFR conditions should continue through most if not all of the taf
period with just diurnal cumulus above 5k feet...cirrus and or ac and
possibly overnight fog.

Winds will be light southwest today and increase to 10 knots or so
after 16z with gusts to 16 knots or so possible. Winds will again be
light tonight.


Ind watches/warnings/advisories...none.



near term...nield
short term...nield

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