Area Forecast Discussion
Issued by NWS Indianapolis, IN
Issued by NWS Indianapolis, IN
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982 FXUS63 KIND 200702 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 302 AM EDT Fri Sep 20 2024 .KEY MESSAGES... - Above normal temperatures continue into the weekend - Isolated to scattered thunderstorms this afternoon and evening - Cooler temperatures early next week with increasing rain chances && .SHORT TERM (Today and tonight)... Issued at 302 AM EDT Fri Sep 20 2024 An upper trough will pivot from the upper Midwest to northern Ontario through tonight as a dome of high pressure remains parked over Texas. Meanwhile, a weak cold front will move into the Wabash Valley this evening spread into southern Indiana by Saturday morning. MRMS reflectivity was showing widespread convection across Wisconsin with more scattered activity southwest into Iowa along and ahead of this front. As the front reaches central Indiana, it will have limited low level moisture and weak to moderate instability to work with after examining Hi-Resolution soundings. In addition, lapse rates will be weak. So confidence in anything other than isolated late day and evening convection is low. That said, with marginal 30-35 knot deep shear to go with the weak to moderate instability and a curved hodograph, would not rule out marginally severe hail and or thunderstorm gusts per the SPC Day1 Severe Weather Outlook. Best timing and highest chances will be after 19z and over the upper Wabash Valley. Once again, deep mixing, diurnal heating and light breezy southwest winds should result in well above normal temperatures in the upper 80s and lower 90s today. Meanwhile, the frontal passage should have little effect on temperatures tonight with lows in the 60s. Normal high temperatures for this time of year are in the upper 70s and lower 80s and normal lows are in the 50s. && .LONG TERM (Saturday through Thursday)... Issued at 302 AM EDT Fri Sep 20 2024 Some relief from the recent hot and dry conditions appears to be on the way for next week, with growing chances for enough of a soaking rain to at least prevent worsening of ongoing drought conditions, and perhaps offer some improvement. Guidance is generally in agreement on a weakening of the persistent subtropical ridge that has kept us dry and hot in recent days and weeks, allowing for multiple upper level disturbances to impinge upon the area late in the weekend into early next week. Model precipitable water values are anomalously high well into next week, which should allow for rainfall as modest forcing moves through the region. Model spread increases from mid week onward with respect to evolution of the synoptic pattern, which will significantly impact resultant conditions, but broadly speaking, expect the first significant rainfall chances in quite some time Sunday into Tuesday, along with a fairly substantial cooldown to much nearer climatological normals, followed by continued milder conditions and perhaps some low rain chances late in the week into next weekend, depending upon the degree to which the upper level ridge reasserts influence near the region. Model QPF is likely a bit overdone given the relatively modest forcing, but WPC 7 day QPF of an inch or two total is certainly reasonable and would put a substantial dent in the monthly deficit, were it widespread enough. && .AVIATION (06Z TAF Issuance)... Issued at 1008 PM EDT Thu Sep 19 2024 Impacts: - Isolated convection possible late Friday afternoon and evening - Winds 210-230 degrees with gusts less than 20 knots Discussion: Would not rule out some late afternoon and evening thunderstorms as a cold front moves in. However, chances are too low to put in the TAFs. Otherwise, good confidence in VFR flying conditions through the TAF period. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...MK LONG TERM...Nield AVIATION...MK