Area Forecast Discussion
Issued by NWS Indianapolis, IN
Issued by NWS Indianapolis, IN
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446 FXUS63 KIND 280926 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 526 AM EDT Fri Jun 28 2024 .KEY MESSAGES... - Increasing clouds and humidity today - Rain and storms return Friday night into Saturday - A few strong to potentially severe storms possible Saturday && .SHORT TERM (Today and tonight)... Issued at 201 AM EDT Fri Jun 28 2024 We continue in the synoptic pattern of low-amplitude shortwave troughs periodically passing to our north, causing a north-south slosh of richer moisture. Humidity was fairly low yesterday but will return today. The mixing process may slow the return some, but once mixing subsides a northward flux of rich moisture should accelerate. All of this is in response to the next upstream shortwave trough. Convection is ongoing now from the northern Plains into the northern Mississippi Valley, fed by ongoing warm/moist advection. Although its easterly track will bring it into a comparatively more stable environment later today, one or more MCVs may evolve and move into Indiana. Midlevel clouds and some light precipitation would be the most likely outcome late this afternoon. Continued moisture advection into the evening and overnight should result in an increase in coverage of convection and/or maintenance of upstream convection from the diurnal temperature maximum. CAPE/shear values would be marginally supportive of severe storms, especially for any well-organized cold pool-driven systems that made it this far east. && .LONG TERM (Saturday through Thursday)... Issued at 201 AM EDT Fri Jun 28 2024 Saturday and Saturday Night The long term will begin fairly active with rain expected along with the potential for a few strong to severe thunderstorms. Overall the the next week will consist of a prototypical low amplitude, meridional pattern with broad high pressure entrenched over the southern CONUS pushing the upper level waves over the northern 48. The first wave in this pattern will approach from the west late Friday into Saturday, with a push of moisture upstream of the upper trough. The moisture push will help induce weak low level diabatic height depressions. The result will be broad lift in a buoyant warm sector with scattered to numerous showers and thunderstorms across the Mid-Mississippi Valley Friday night. By the time this source of lift reaches central Indiana, diurnal cooling will have capped much of the low level moisture. Still showers and isolated thunderstorms will likely push through Saturday morning. As solar heating increases in the late morning to early afternoon, greater surface based instability may allow for a few thunderstorm updrafts to intensify enough for strong to severe gusts/hail. Some ensemble members are picking up on a slower progression of this initial wave, of which would increase the severe threat slightly by providing a more untouched and buoyant atmosphere. Following this initial wave, a more potent source of lift along an advancing cold front will work its way into the region. However, There is still a lot of uncertainty on if there will be enough instability for thunderstorms to initiate on the progressing boundary. If thunderstorms do develop there will be a damaging wind threat with a very dry low to mid level layer, leading to high DCAPE values, but at this time this looks unlikely. Sunday Through Thursday. The aforementioned low amplitude meridional pattern will continue through the the rest of the long term. Initally, the will lead to cool, calm conditions with surface high pressure and upper level troughing for Sunday and Monday. This should allow for generally clear skies and highs around 80 along with the near surface flow veering towards northerly to northwesterly. The next phase of the this pattern will arrive mid week, with broad ridging developing aloft. This will push highs back to around 90 by Wednesday. Periodic rain chances will coincide with increasing temperatures as weak low level waves pass through the region. Thunderstorms will also be possible mid to late next week within these wave passages. && .AVIATION (12Z TAF Issuance)... Issued at 526 AM EDT Fri Jun 28 2024 Impacts: - Showers possible toward the end of the TAF period Discussion: Clouds will increase but ceilings will remain high enough for VFR conditions to prevail. Showers and low probability of thunder will start this evening and peak Saturday morning. Timing in TAFs with PROB30s may need to be refined further with subsequent updates. Winds will veer gradually from southeasterly to south-southwesterly. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...BRB LONG TERM...Updike AVIATION...BRB