270 
FXUS63 KIND 161406
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1006 AM EDT Wed Jun 16 2021

.Forecast Update...
Issued at 1001 AM EDT Wed Jun 16 2021

Forecast is in good shape. Satellite shows mostly generally clear
skies at the moment other than some thin cirrus overhead. Did
slightly tweak winds as needed, but they are still expected to be
light and variable through the day. 

&&

.Short Term...(Today through Thursday)
Issued at 512 AM EDT Wed Jun 16 2021

Surface analysis early this morning shows strong high pressure in 
place over Lake Superior...extending south through the Ohio Valley 
toward the lower Mississippi River Valley. Water Vapor shows a 
strong...highly amplified ridge in place over the northern 
plains...providing lee side NNW flow to the Great Lakes and Indiana. 
GOES16 shows a few high clouds passing within the flow across 
central Indiana...but for the most part skies were clear. Dew point 
temps were in the very comfortable lower 50s. 

Today...the models continue to depict the large high pressure system 
moving ever slowly southward toward Indiana and Illinois. Aloft the 
sharp ridge is expected to make progress toward the Western Great 
Lakes...keeping the lee side subsidence in play across Indiana. 
Forecast soundings reveal a dry column. Thus will expect more of the 
same with today's weather...mostly sunny and warm summer time temps. 
Will not veer far from the NBm on temps. 

Tonight...Little change in the overall weather is expected tonight. 
The upper ridge axis is expected to still be intact over the Great 
Lakes...with lee side northerly flow spilling across Indiana. The 
associated surface high pressure system will be firmly in place 
within the Ohio valley...once again providing clear skies and light 
winds. Forecast soundings again are dry. Thus mostly clear and temps 
near the NBM will be the way to go.

On Thursday the sharp upper ridge axis is depicted to diminish 
somewhat as it settles across Indiana. Subsidence should still be in 
play beneath this axis...but warmer air will be expected to arrive 
as surface high pressure drifts toward Appalachia and a southerly 
surface flow develops. Forecast soundings and Time heights here 
continue to depict a dry column...although given the ridge axis 
placement would not be surprised to see some ridge riding cirrus 
aloft. Thus will trend toward mostly sunny once again...but with 
temps at or above the NBM.

&&

.Long Term...(Thursday night through Tuesday)
Issued at 512 AM EDT Wed Jun 16 2021

Thursday night...

The pattern begins to become more active Thursday night into Friday 
as Indiana remains sandwiched between a strong ridge across the 
Rocky Mountains and broad troughing across the Eastern United 
states.  A shortwave will be rounding the top of the ridge on 
Thursday with a strong MCS expected to initiate across the Northern 
Plains Thursday afternoon. Going into the late overnight hours, this 
MCS is currently progged to advance to the southeast with impacts 
likely to the forecast area after midnight.  The MCS is expected to 
be moving into a fairly unfavorable environment by later Thursday 
night which should lead to gradual weakening, but if the cold pool 
can maintain a good balance with the weak shear, severe wind gusts 
can't be ruled out.

Friday...

Much of the weather for Friday will be heavily dependent on how far 
the MCS progresses, but the return of southerly flow should lead to 
a hot and humid day with model estimates of afternoon CAPE easily 
exceeding 4000 J/kg which would be the most extreme values seen all 
year.  Stronger winds aloft associated with the jet also will help 
bring effective shear of 30-40kts which when combined with the 
expected instability should lead to the potential for another round 
of severe weather late afternoon into the evening.  If the MCS 
leaves more convective debris in the form of clouds across the area, 
that severe threat may be diminished. 

Saturday through Tuesday...

Going into the weekend and early next week, isolated to scattered 
thunderstorms will continue as the ridge breaks down and a broad 
trough moves into the Central United States.  Southerly flow won't 
be quite as strong late this weekend into early next week, so the 
overall threat for stronger storms is low with the lessened 
instability and expected minimal shear.  A weak cold front should 
also pass through the area Monday into Sunday night which should 
further push out the moist air and leave behind more pleasant 
conditions going into next week.

&&

.Aviation...(12Z TAF Issuance)
Issued at 618 AM EDT Wed Jun 16 2021

IMPACTS:

- VFR Conditions expected this TAF period. A few-scattered cumulus 
  Will be possible during peak heating today.
- Winds will generally be 7kt or less and from 330-030.

DISCUSSION: High pressure will build in during the period. Forecast 
soundings and Time height sections continue to show a dry column 
through the period. The high pressure will allow lower wind speeds, 
but may bring some variability to the wind at times through the 
period.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Update...KH
Short Term...Puma
Long Term...White
Aviation...JP