Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 200722
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
322 AM EDT Mon May 20 2019

.UPDATE...
The LONG TERM Section has been updated below.

&&

.SYNOPSIS...
Issued at 229 AM EDT Mon May 20 2019

High pressure will move across the area into Tuesday. A frontal
system is expected to move through the area around Wednesday.
Another frontal system may set up over the Great Lakes towards the
end of the week.

&&

.NEAR TERM /Today/...
Issued at 229 AM EDT Mon May 20 2019

Dry weather expected today as surface high pressure builds into the
Midwest. There will probably be a decent amount of diurnal cloud
cover later today, given 850mb thermal troughing over the Great
Lakes.

Low level thicknesses suggest the GFS MOS highs for today look good,
so little if any adjustments will be made.

&&

.SHORT TERM /Tonight through Wednesday Night/...
Issued at 229 AM EDT Mon May 20 2019

Model data suggest dry conditions will hold across the local area
through Tuesday as high pressure drifts through the Great Lakes.
Some ensemble members suggest a warm advection precipitation threat
ahead of Plains system may clip the northwest zones on Tuesday, but
not a strong enough signal to add to the forecast at this time.

Better threat for shower and thunderstorm activity appears to be
late Tuesday night into Wednesday, as model data suggest a mid level
vorticity lobe rotating out of Plains low, is expected to move
through the local area. Not sure how extensive convection may be
with this system, as it should be weakening as it encounters mean
upper ridge over the Ohio Valley. However, deep layer shear will be
quite favorable for strong organized convection by late Tuesday
night into Wednesday morning. Will go with some PoPs for Tuesday
night into Wednesday to cover this system.

Progged low level thicknesses suggest the GFS MOS highs for Tuesday
look a little on the cool side. Will bump up the highs Tuesday about
2-5 degrees. The rest of the periods look OK for now.

&&

.LONG TERM /Thursday through Sunday/...
Issued at 322 AM EDT Mon May 20 2019

A summerlike pattern will develop across the Ohio Valley for the
latter part of the week and into the holiday weekend with warm and
humid conditions along with periodic threats for scattered
convection as a frontal boundary meanders over the lower Great
Lakes.

An amplified upper level flow regime will develop across the
country with a persistent trough setting up over the Intermountain
West. This will promote a broad ridge downstream over the central
and eastern part of the country...likely bringing the warmest and
most humid air of the year so far to central Indiana and the Ohio
Valley. Expect highs in the mid and upper 80s through Saturday...
perhaps slipping back a bit on Sunday as the aforementioned
frontal boundary sags into the area.

The presence of the front oscillating across the lower Great
Lakes will keep the forecast area within the warm sector south of
the boundary...but it will remain close enough to central Indiana
to warrant low chance pops throughout much of the extended.
Trying to provide any additional detail to the convective threats
at this point is rather futile as specific location of the
boundary and timing of any waves rippling along the front will
both determine the potential for timeframes with increased
threats for storms. For that reason blend pops were largely
accepted throughout the period.

&&

.AVIATION /Discussion for the 20/06Z TAF Issuance/...
Issued at 1151 PM EDT Sun May 19 2019

VFR will be the predominant flight category for the TAF period,
but will not rule out some MVFR stratocu from Mon 14-16Z. Current
southwest winds will continue to veer to the northwest today and
will generally be in the 5 to 11 kt range with some occasional gusts
to 22 kts at times in the wake of cold front.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....Ryan
AVIATION...TDUD


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