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
061 FXUS63 KIND 080411 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1211 AM EDT Mon Jul 8 2024 .KEY MESSAGES... - Mostly Clear Tonight - Beryl will bring rain, heavy at times to central Indiana late Tuesday through Wednesday. Areal flooding will be possible within the heaviest rainfall axis. && .FORECAST UPDATE... Cu has largely diminished as we pass sunset with the eastern fringes of a mid level cloud deck associated with a frontal boundary across the Missouri Valley drifting across the northern Wabash Valley. 01Z temperatures ranged from the mid 70s to the lower 80s. The overall forecast for the rest of the night is in excellent shape. While high pressure continues to move away to the east... surface ridging will linger keeping skies mostly clear overnight. The bulk of the mid level clouds will remain to the west although may see that subtly expand into the region towards daybreak. Lows tonight will fall into the mid 60s. Zone and grid updates out. && .SHORT TERM (This evening through Monday)... Issued at 251 PM EDT Sun Jul 7 2024 Surface high pressure, over the eastern Great Lakes, was providing subsidence and tranquil weather this afternoon. Meanwhile, visible satellite and obs were indicating just scattered diurnal cu over the sky. The abundant Summer sunshine has allowed temperatures to warm into the lower and middle 80s. That said, the heat index has not been a big issue with this relatively dry airmass. Meanwhile, the weak pressure gradient is resulting in light southerly winds. Tonight... The diurnal cu will dissipate toward sunset and high pressure will continue to influence the weather with a good radiational setup once again tonight. A dry column per Hi-Res soundings along with light to calm winds will allow temperatures to bottom out near afternoon dew points, in the middle 60s. Monday... Surface high pressure, over the eastern Great Lakes, and a dry column will once again result in benign weather through early afternoon Monday. However, by afternoon, soundings are indicating the column moistening ahead of an advancing upper Midwest trough. Thus, expect an increase in cirrus and perhaps mid level clouds to go along with diurnal cu. This could keep temperatures slightly below the above normal model blend. In addition, would not rule out some late day scattered convection over the upper Wabash Valley. Instability progs support thunder chances there as well. && .LONG TERM (Monday night through Sunday)... Issued at 251 PM EDT Sun Jul 7 2024 Monday Night through Thursday... The main concern through midweek will be heavy rain and potential flooding associated with the remnants of Beryl. Currently, the timing for the heaviest and most widespread rainfall will be Tuesday night and Wednesday. The 12z GFS and ECMWF runs have diverged with the Euro keeping the northwestern track of the low compared to the now southeasterly GFS track. Both lie in the cone of the official NHC forecast track but the preferred Euro is right down the middle of the track. So, kept the heaviest rain axis over the upper Wabash Valley with up to 1 to 3 inches in that area and around an inch elsewhere. This is within reason of ensemble QPF viewed in DESI and has trended slightly down. If the path shifts towards the GFS, so to would the heaviest rain axis. Needless to say though, confidence in exact timing and location of the most impactful rainfall is still far from ideal but with potential frontogenetical banding, areas within the axis of heaviest rainfall have the potential to receive higher amounts than mentioned above. In the end, an areal Flood Watch may be needed at some point for at least parts of central Indiana. Meanwhile, OHRFC river ensembles were showing very few members suggesting minor flooding later next week, so refrained from an ESF. In addition to the heavy rain and flooding threats, windy conditions are also a concern with the remnants of Beryl. Raised the blend winds in agreement with adjacent offices to cover that as the official NHC forecast/ECMWF track across the upper Wabash Valley would favor that. Due to the widespread cloud cover and rain, temperatures will be below normal and no warmer than the lower 80s. Thursday night through Sunday... Broad high pressure will build in for the weekend even as a broad trough lingers over the Ohio and Tennessee Valleys. Drying column per soundings and subsidence is expected to provide decreasing cloud cover and a return to above normal temperatures with lower 90s possible by Sunday. && .AVIATION (06Z TAF Issuance)... Issued at 1209 AM EDT Mon Jul 8 2024 Impacts: - VFR Conditions are expected this period. Discussion: Strong and large high pressure east of Indiana will continue to control the weather across the TAF sites for one more day. Once again diurnal CU will be expected this afternoon as convective temperatures are reached. Due to the developing SW flow aloft, and mid and upper moisture across the souther plains, some high cloud cigs will be pushed across the TAF site through the day. As the upper trough edges eastward, some isolated convection will be possible within the Wabash Valley late in the afternoon. Confidence is low for this, and for now a mention will not be included, but this could be a chance in a later forecast should trends continue. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Ryan SHORT TERM...MK LONG TERM...MK AVIATION...Puma