Area Forecast Discussion
Issued by NWS Indianapolis, IN
Issued by NWS Indianapolis, IN
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196 FXUS63 KIND 300515 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 115 AM EDT Thu May 30 2024 .KEY MESSAGES... - Light rain ending this evening, quiet and dry through Friday. - Rain and thunderstorm chances Saturday into Sunday. - Warming trend early next week. && .FORECAST UPDATE... Issued at 924 PM EDT Wed May 29 2024 Clouds are diminishing quickly across the region this evening as high pressure builds in. Showers have largely shifted into western Ohio and should pull further away from the forecast area. 01Z temperatures were generally in the 60s. The high will expand into the region overnight with mainly clear skies and light northerly flow. Low level thermals support a chilly start by late May standards for Thursday morning...with lows ranging from the mid and upper 40s in the northern Wabash Valley into the lower 50s elsewhere. Zone and grid updates out. && .SHORT TERM (This evening through Thursday)... Issued at 300 PM EDT Wed May 29 2024 Rest of Today/Tonight. Light rain showers continue across the eastern counties as northerly flow continues on the backend of the low pressure system that brought multiple rounds of showers and storms to central Indiana over the last few days. As of early this afternoon, showers had ended for points west of Indianapolis with highest coverage from Muncie to Rushville and points to the east. Clouds have gradually begin to clear to the west as dry air continues to slowly make its way into central Indiana and the forcing associated with the low pushes further to the east. Expectations are that by the early overnight hours that skies will be mostly clear. Afterwards, quiet conditions are expected through the night with efficient radiational cooling and dry surface air allowing for temperatures to drop into the upper 40s to around 50. Thursday. A very pleasant day is expected for Thursday with mostly clear skies, temperatures in the low 70s, and dewpoints in the mid 40s. Surface flow will gradually become more easterly by mid morning as high pressure begins to move into the Great Lakes region. RH values will drop to between 30 and 40 percent but with near calm winds the fire weather risk will be near zero, especially with recent rains. && .LONG TERM (Thursday night through Wednesday)... Issued at 300 PM EDT Wed May 29 2024 Synoptic flow through the remainder of the week will be characterized by troughing over the eastern US with a ridge translating eastward with time. This ridge looks to arrive towards the end of the week. Thereafter, guidance tends to show a more zonal to quasi-zonal pattern taking shape. This looks to persist into next week with occasional shortwave/vort maxes providing periodic rain chances. By mid to late next week, ensemble guidance shows a strong signal for ridge-building over the western US with troughing over the east coast. In terms of sensible weather through the long range, generally quiet conditions look to persist as we head into the weekend. An expansive area of surface high pressure will be overhead tonight through Friday, at least. Strong subsidence and a dry column will bring clear/mainly clear skies through Thursday. Temps should remain near to below normal with a large diurnal spread. Cirrus debris from upstream convection should far enough away to not be noticeable. Though some more pessimistic members of guidance bring this in late Thursday/early Friday. Regardless, this cirrus will likely be thin for the most part. Cloud cover likely increases by late Friday and into the weekend as the primary ridge axis shifts eastward. Additionally, the surface high also shifts eastward allowing low-level flow to become more southerly/southwesterly. Such a configuration will lead to a good period of warm air and moisture advection over the weekend. A return to more humid conditions appears likely. But does that translate into shower/thunderstorm chanceS? As of right now it does appear so, mainly because of a shortwave progged to arrive on Saturday. Guidance seems to be in good agreement with this feature. Will carry chance PoPs over a broad time range to account for the model agreement with this feature but also some uncertainty with timing. After the weekend guidance returns us to zonal or quasi-zonal flow with embedded shortwaves. Model agreement tends to diminish regarding these smaller-scale features and so our confidence in the forecast likewise decreases. Still, some useful information can be said about the forecast this far out. Namely, zonal flow aloft with southerly (or at least a southerly component) flow at the surface will likely lead to a warming trend. Temperatures have recently been nearer to the late May average (mid to high 70s), and guidance shows a rise into the low 80s early next week. Additionally, a trend towards troughing late next week (beyond the end of the Long Range period) should bring about a cooling trend in the day 8-14 range. && .AVIATION (06Z TAF Issuance)... Issued at 114 AM EDT Thu May 30 2024 Impacts: - VFR conditions throughout the forecast period Discussion: A broad upper trough over the region continues to shift eastward with upper ridging beginning to build in. This has allowed skies to clear out across central Indiana. Expect winds to remain light through the period as surface high pressure settles in. Wind direction will be northerly trough daybreak and then should veer to northeasterly during the day. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Ryan SHORT TERM...White LONG TERM...Eckhoff AVIATION...Melo