Area Forecast Discussion
Issued by NWS Indianapolis, IN
Issued by NWS Indianapolis, IN
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
379 FXUS63 KIND 122206 AAA AFDIND Area Forecast Discussion...UPDATED National Weather Service Indianapolis IN 606 PM EDT Wed Jun 12 2024 .KEY MESSAGES... - Quiet weather expected through much of the day Thursday, Warming trend continues with highs near 90F by Thursday - Thunderstorms possible Thursday night...with possibly a few strong/severe cells north of I-70 - Hot and humid trend starts Sunday && .FORECAST UPDATE... Issued at 606 PM EDT Wed Jun 12 2024 Latest visible/DCP RGB satellite imagery shows cumulus field within a narrow band of enhanced moisture just ahead of a cold front. Wake subsidence behind departing shortwave perturbation is making for a hostile environment for sustained deep convection, thus the large "splotches" of cumulus are observed, typical of a strongly capped environment. There may be a short window for an isolated convective shower early this evening if the subsidence layer erodes sufficiently toward the tail end of the diurnal maxima. Coverage will be minimal if any showers do develop. There is a cold pool-driven area of convection and attendant MCV over southern Wisconsin. The downstream environment features modest instability and shear, and may be supportive of sustenance a bit longer than CAMs indicate, but the richer moisture/instability axis is narrow and positions north of our area. So, it appears unlikely any impact will occur later tonight from remnant MCS other than high-level cloud debris. && .SHORT TERM (This evening through Thursday)... Issued at 301 PM EDT Wed Jun 12 2024 Expect quiet weather conditions to persist through the short term period as surface high pressure remains in control. Latest surface observations show the aforementioned high near southeastern Indiana and Kentucky. A weak frontal boundary which moved into far NW counties this morning has stalled. Earlier thoughts were that daytime heating over this negligible convergence zone could be enough to force a few light showers this evening. Confidence remains very low in this scenario due to weak forcing. Will continue to keep a dry forecast for this reason, but cannot completely rule out a few light showers over far NW counties. Plentiful sunshine combined with increasing southwesterly flow has allowed temperatures to warm up considerably after a brief cooldown over the past few days. Good radiational cooling conditions tonight should allow for temperatures to fall well into the 60s, possibly upper 50s in a few spots over far S/SE portions of the area where winds will be nearly calm. Temperatures will then warm into the upper 80s and possibly low 90s for some location Thursday with increasing southwesterly flow and mostly sunny skies. Thankfully dewpoints should remain in the 50s, but this will likely be the hottest day of the year so far. Some increase in mid-high clouds may be evident early in the day from an upper level impulse moving over the northern Great Lakes Region. Additional clouds are expected towards the evening as a system approaches. Details on this system will be covered in the extended period. && .LONG TERM (Thursday night through Wednesday)... Issued at 301 PM EDT Wed Jun 12 2024 Thursday night through Saturday... The long term will begin with a conditional strong to severe t-storm threat as convection expected to initiate late Thursday between the Iowa/Illinois region matures to the west of central Indiana Thursday evening...and then most likely slowly collapses while steadily crossing Indiana in a southeasterly direction up to pre-dawn hours. The front end of this convective cluster may bring a few marginally strong/severe storms, focused near the Upper Wabash Valley... although stronger gusts could make it as far as the I-70 corridor, especially if storms started earlier Thursday and/or closer to the CWA. Otherwise this should be the most organized rainfall of the forecast period...with most areas picking up 0.10-0.50 inches along an overall NW/SE gradient, and perhaps isolated areas up to 0.75- 1.00 inches under one or two stronger/slower cells. No flooding concerns following recent drier pattern and rather brief window of possibly steadier rain. The remainder of this week will be marked by subtle relief from the broader trend into a more summerlike pattern...as seasonably strong Canadian surface high pressure following the Thu night wave... crosses the Great lakes during Friday-Saturday, bringing lower heights and H850 temperatures. Corresponding modest northerly flow will promote afternoon highs closer to the mid to upper 80s both days, along with dewpoints that should hang in the 50s...providing more of a June than July feel to start the weekend under ample sunshine. Sunday through Wednesday... The broad subtropical upper ridge, building northward while slowly crossing the CONUS through Saturday...will then envelope the Midwest through at least the first several days of next week. Latest guidance is continuing to show stagnant upper troughiness settling over the northwestern CONUS, which will further promote the ridge building over the eastern half of North America as well as light to moderate southerly surface flow into Indiana which will also serve to boost dewpoints to at least moderate levels. Surface cyclogenesis expected to occur from the central High Plains to western Ontario through the early week may help boost this breeze, albeit while continuing to advect heat and humidity into the Midwest. At least a few afternoon showers and t-storms will be possible amid this hot/humid period when precipitable water values will be around 1.50 to 2.00 inches, although little confidence in location and timing of any such disorganized convection, with little if any forcing and any boundaries based on previous days` outflow. Bigger story will be widespread high temperatures 90-95F, especially Sunday and Monday when H850 temperatures will approach 20 Celsius. Higher dewpoints will promote maximum heat indices in the 90s to possibly around 100F if any showers/scattered clouds could be dodged. The normal max/min at Indianapolis through the long term is 82/63. && .AVIATION (00Z TAF Issuance)... Issued at 606 PM EDT Wed Jun 12 2024 Impacts: - None. Discussion: VFR conditions will continue. Winds may vary slightly during the TAF period by around 30 degrees or so with the dirunal cycle, but generally southwesterly. Mixing may be enough for momentum transfer and gusts up to around 15-20 knots Thursday afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...BRB SHORT TERM...Melo LONG TERM...AGM AVIATION...BRB