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Area forecast discussion 
National Weather Service Indianapolis in
425 am EDT Wednesday may 6 2015


The aviation section has been updated below.


issued at 357 am EDT Wednesday may 6 2015

Upper level ridging will be the dominant factor across the area
through tomorrow evening. A frontal system will approach Friday
into the weekend and bring frequent thunderstorm chances through
much of the remainder of the forecast period.


Near term /today/...
issued at 357 am EDT Wednesday may 6 2015

Although convective temperatures appear likely to be
reached...with upper level ridging overhead and thus subsidence
predominating throughout the column...this should result only in
some flat fair weather cumulus.

Temperatures have continued to outperform consensus numbers in
recent days...and will again raise maxes above consensus. Should
easily see the middle 80s in most locations today. Maximum temperature forecast
of 85 for indy would be the warmest day in 8 months.


Short term /tonight through Friday night/...
issued at 357 am EDT Wednesday may 6 2015

Expect upper level ridging to continue suppressing significant
convection through Thursday and into Thursday night. Will continue
with a dry forecast through then...and continue to reintroduce
thunderstorm chances Friday and into Friday night as a frontal
system approaches from the west. System appears unremarkable and
at this time do not expect a widespread severe threat.

On temperatures...continue to expect maxes to outperform consensus and
have adjusted grids as such. Middle 80s should predominate through at
least Friday. Min temperature guidance appears slightly too warm based on
recent trends and have increased the diurnal range slightly as a


Long term /Saturday through Tuesday/...
issued at 250 am EDT Wednesday may 6 2015

Unsettled weather is on tap for much of the extended and model
differences in handling of an upper and surface system are leading
to some uncertainty as to when thunderstorm chances should end and
also with temperatures early next week.

Deterministic models and ensemble 500 millibar height means start
off pretty close with an upper low near the border of southwestern
Utah and northwestern Arizona by 12z Saturday. This will result in
southwest upper flow over the Great Lakes and Ohio Valley. As both
the upper low and a surface reflection lift northeast through the
weekend...the model solutions diverge a bit with the 00z European model (ecmwf)
further north with both than the 00z GFS or gefs by 00z Tuesday. The
European model (ecmwf) has a surface low over western Wisconsin and the GFS over
northeastern Illinois at that time. Either way though...southerly
flow ahead of the surface low and associated cold front...and upper
waves in the southwest flow aloft...should result in a warm...moist
and unstable atmosphere through through weekend and early next week.
This should result in an unsettled period with thunderstorm chances
through at least Monday. It will also result in cooler weather by
Tuesday per the regional blend which has highs in the 70s and 80s
through Monday but highs only in the 60s by Tuesday.


Aviation /discussion for the 060900z ind taf update/...
issued at 425 am EDT Wednesday may 6 2015

No major changes to the taf.

Previous discussion follows...

Issued at 1215 am EDT Wednesday may 6 2015

Other than a brief period with MVFR visibilities at klaf around
daybreak...VFR conditions expected. Partly to mostly clear skies
this morning with just mainly passing cirrus. Southwest winds have
dropped off to light and variable and will pick back up later this
morning but remain below 10 knots for the rest of the period.


Ind watches/warnings/advisories...none.



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

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