Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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
735 FXUS63 KIWX 171059 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 659 AM EDT Wed Jul 17 2024 .KEY MESSAGES... -Rain showers and isolated thunderstorms are possible today, mainly along and south of US 24 this morning into mid afternoon. Heavy rain, minor flooding or ponding of water on the roads, and lightning are the main threats. Gusty winds are possible this afternoon. -Dry and less humid conditions persist from tonight into early Monday, with variable cloud cover and highs in the 70s and low 80s. -There is a moderate swim risk on Lake Michigan beaches today and Thursday. Breaking waves and currents are expected. && .DISCUSSION... Issued at 425 AM EDT Wed Jul 17 2024 There could be some patchy fog this morning, with some of the sites in northern Indiana showing 1 to 3 mile visibility. Expect we`ll see improvement towards sunrise as we commence daytime mixing. The cloud cover kept us somewhat limited in the amount of radiational cooling, and I suspect they will linger just long enough to keep the fog development from becoming more widespread. That being said, I wouldn`t be surprised to see a few northern IN sites drop to less than 1 mile just before sunrise. If this occurs, may end up issuing an SPS to cover the hazard through around 9 am EDT depending on the extent. Holding off for now. Scattered showers and thunderstorms associated with a cold front (sinking southeast) and a weak surface boundary developed overnight, generating around 1-2 inches of rain in several areas (near Columbia City, IN). There was a narrow strip of around 500-700 J/kg of CAPE that is weakening now as the cold front continues to sink southeast, as we`re far departed from daytime heating, and low level moisture has begun to dwindle a bit. Expect some continued scattered to isolated showers and maybe storms again this afternoon as we get instability with daytime heating and a weak mid level wave moves through, but expect this mainly along/south of US 24 once the morning precipitation dwindles off. Greatest threat in any storms today will be torrential rainfall and minor flooding/ponding of water on the road. Gusty winds are also possible, but expect things to stay below severe limits (gusts to maybe 20-40 mph with DCAPE around 600 J/kg per the NAM). Otherwise, expect northwest flow to become more breezy, with a few gusts around 20-25 mph expected this afternoon. There is a moderate swim risk on Lake Michigan for breaking waves and current activity today, which will continue into tomorrow, especially as wave periods lengthen to 5-6 seconds. Highs will rise into the mid-upper 70s and low 80s. Lows tonight will be in the 50s. High pressure will build in at the surface with mid level height rises Thursday morning into the weekend. Despite several weak waves moving through in the flow aloft this weekend, the ridging appears to hold somewhat and keep us dry. The surface high will slowly meander eastward through IN/MI/OH then wash out somewhat towards Saturday night and Sunday, though we stay dry through at least Monday afternoon. During this period we`ll welcome less humidity and more agreeable temperatures-highs in the mid-upper 70s-low 80s and lows in the upper 50s-60s. Another trough will dive into the central CONUS for Mon afternoon- Tuesday, drifting east through Thursday into our area. A surface low will lift northward from near TN/KY Monday afternoon into Tuesday morning, with WAA associated with the warm front bringing some chances for showers and storms by Monday afternoon. The front stalls there and provides a focus for rain and storms through Tue/Wed. Highs will be in the 70s and low 80s. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 656 AM EDT Wed Jul 17 2024 Isolated showers are likely to persist into the morning before ending this afternoon. Otherwise, VFR conditions will prevaill with winds under 10 knots. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...MCD AVIATION...Skipper