Area Forecast Discussion
Issued by NWS Indianapolis, IN
Issued by NWS Indianapolis, IN
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068 FXUS63 KIND 100146 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 946 PM EDT Sun Jun 9 2024 .KEY MESSAGES... - Unseasonably cool Monday - Mid-week moderation will bring highs near 90F by Thursday - Mainly dry past low-chances of showers/t-storms Thu Night-Friday && .FORECAST UPDATE... Issued at 946 PM EDT Sun Jun 9 2024 Much of the cumulus have dissipated so far this evening, and clouds from the approaching upper trough are still well upstream, so skies have become mostly clear across much of central Indiana. The lower atmosphere remains quite dry, with dewpoints in the 40s to around 50 at most locations. Forecast is still on track. Skies will stay mostly clear until the overnight when clouds will increase from the north with the upper trough and behind the surface cold front. The dry atmosphere and period of mostly clear skies will allow temperatures to cool into the lower and middle 50s for low temperatures. && .SHORT TERM (This evening through Monday)... Issued at 300 PM EDT Sun Jun 9 2024 The cirrus shield associated with the earlier convective cluster to our southwest has continued to shift south into the early afternoon as cloud tops warm and diminish overall. Diurnal cu has formed in its place especially across the northern half of the forecast area as the upper trough anchored across the northeast States has begun to amplify. Temperatures are comfortable this afternoon with mid and upper 70s common across central Indiana as of 18Z. The aforementioned upper trough will serve as the main influence across the region through the short term...with increasing amplification of the trough tonight and Monday before shifting away from the Ohio Valley Monday night. With an expanding area of high pressure at the surface approaching from the northwest on Monday as well...the stage is set for a brief shot of cooler air before Summer is set to arrive in earnest later this week. Monday will not only be the coolest day of the next 7 days...but it very likely will be the coolest day across the region for the foreseeable future. Gusty northwest winds will be the primary impact for the rest of the afternoon as soundings already showing a well mixed airmass up to about 800mb currently that is likely to mix even higher by the end of the afternoon. Peak gusts at 25 to 30mph will continue through the remainder of the afternoon before diminishing this evening. Cu will persist into the early evening then dissipate near sunset. Expect highs to peak in the upper 70s and lower 80s over the next few hours. Skies will be mainly clear to start this evening but a broad area of lower stratus and stratocu dropping south currently through the Great Lakes will advect into the region early Monday associated with a wave aloft aiding in the mean trough amplification. Model soundings and RH progs both supporting an expansion of lower stratus into the northern half of the forecast area Monday morning. The question then becomes how extensive the cloud cover will be and how long it will hold on Monday. While cold advection will be ongoing... broad stratus lingering for a full day in June is difficult considering that our sun angle is at nearly peak level for the year. Suspect that as the wave aloft shifts off to the east Monday afternoon...will see stratus mix out into a cu field with the greatest coverage over the northeast half of the forecast area where cold advection will remain strongest. The lingering cu along with a resumption of breezy winds from the north will make for a distinctively early Fall feel to the air on Monday. Temps...cool night expected tonight with lows falling into the 50s. Could see a few spots make a run at the upper 40s in northern counties but think the arrival of the stratus late will keep that from occurring. As mentioned above...Monday is easily set up to be the coolest day for the foreseeable future. Nudged temps down based on the expected cloud coverage and cold advection regime with highs in the upper 60s and lower 70s from north to south. After a chilly Monday night...temperatures will quickly recover through the week with heat on the horizon. More on this in the Long Term section below. && .LONG TERM (Monday night through Sunday)... Issued at 302 PM EDT Sun Jun 9 2024 Monday Night through Wednesday... The long term will start on the heels of what may well end up being the coolest day of the foreseeable future Monday...as the inflection point between the departing deep H500 trough and arriving short wave upper ridge crosses Indiana Monday night. Seasonably strong surface high pressure (currently over the Canadian interior Plains) will then cross the local region during Tuesday-Tuesday night...while the upper ridge crossing the Great Lakes breaks down ahead of strengthening upstream retracted/zonal flow. Mostly clear skies will include a period of scattered clouds late Tuesday under a passing ripple in the building zonal ridge. This subtle transition will mark the switch from below to above normal readings amid the steadily moderating pattern. Mainly light southwesterly breezes will bring 80s on Wednesday under H850 temperatures rising to around 15 Celsius. The western extents of the slowly departing/weakening surface ridge will keep the CWA dry through Wednesday night. Thursday through Sunday... Very warm to hot conditions will be the rule throughout the late week and upcoming weekend as the subtropical zonal ridge attempts to build northward over much of the CONUS. A short wave trough will cross the Great Lakes around the Thursday night-Friday night timeframe...which will bring at least isolated rain chances to central Indiana, and likely slightly cooler and less humid conditions around Friday night and Saturday. Not the greatest confidence in the late week precipitation forecast with strong to severe storms likely well to our northwest...which may spill at least scattered peripheral showers across northern Indiana for maybe 6-12 hours ahead of this late-week cool frontal passage. Otherwise mid-summer type marginal heat and moderate humidity should prevail most days, with highs most likely 5-10 degrees above normal and dewpoints often into the 60s. A glance into next week shows the potential continuing for heat...as CPC Max Temp probability of 90F+ at 25-50 percent across the CWA through Day 14...with greatest likelihood of hot conditions south/west of Indianapolis. && .AVIATION (00Z TAF Issuance)... Issued at 653 PM EDT Sun Jun 9 2024 Impacts: - MVFR ceilings at most sites Monday morning - Wind gusts near 20kt possible Monday afternoon Discussion: Cumulus will dissipate some as heating is lost this evening, and wind gusts will diminish as well. Another cold front will move through tonight. Winds will back briefly before the front moves through then return to north and northwest. Clouds will increase once again overnight with MVFR ceilings developing at most sites Monday morning. Clouds will gradually lift and break up Monday afternoon. Mixing will bring some gusts as well. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...50 SHORT TERM...Ryan LONG TERM...AGM AVIATION...50