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