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
375 FXUS63 KIND 221349 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 949 AM EDT Wed May 22 2024 .KEY MESSAGES... - Not as warm, yet continued humid today as a weak cold front slowly crosses the region - Isolated strong/severe storms are possible late today and tonight, mainly south and southeast of Indianapolis...damaging winds and isolated flooding are the most likely hazards - Chances for rain continue through much of the holiday weekend into next week. && .FORECAST UPDATE... Issued at 949 AM EDT Wed May 22 2024 Trends continue to shift precipitations chances further south during the daytime hours. The dynamic parameters are still present, but initiation out in front of the parent boundary looks rather non- existent until later this evening when a secondary shortwave helps create lift. If a storm does initiate this afternoon, is will likely be south of the I-70 corridor. As mentioned, after 00Z, isolated to scattered initiation is expected across the I-70 corridor and locations southward. Strong to severe storms are possible within these cells, with 60 MPH wind gusts and 1" hail as the primary threats. && .SHORT TERM (Today and tonight)... Issued at 303 AM EDT Wed May 22 2024 Today... A potent late spring storm system will cross Ontario today, dragging its trailing cold front slowly across central Indiana from northwest to southeast. The boundary will make more progress across northern counties per the departing cyclone`s eastward advancement...while rather weak surface high pressure nudging east behind the boundary tracking in a quasi-parallel path will slow the front as it approaches the Ohio Valley. Convection crossing the region early this morning will weaken, due to better forcing departing north... while mostly departing to our east, with scattered showers perhaps lingering to the southeast of Indianapolis through daybreak. The slowly-passing front will promote further rounds of mainly isolated shower development...be it northern/central zones this morning...southern counties through midday to early afternoon hours...or perhaps a more favorable set-up for organized stronger cells perhaps along our far south and more likely along the Ohio Valley starting late today. Southwesterly breezes gusting to at least 15-20 mph will veer slightly as the front passes, but still hold moderate humidity across the region...with dewpoints likely reaching the upper 60s over southern zones. Considerable cloudiness ahead of the boundary should scatter out slowly from northwest to southeast as the frontal zone arrives. Despite starting out at near- record-high mild levels this morning in the upper 60s...clouds will promote a more reasonably mild day for late May with most locations reaching the low 80s. Tonight... The frontal zone to the north-northwest of the lingering, quasi- stationary boundary slowly passing the Ohio Valley will provide modest lift and help to focus any next round of showers and thunderstorms over southern portions of Indiana. Convective ingredients will be more favorable through evening hours...when both instability and mid-level lapse rates will be adequate from far- south to southeastern zones, while bulk shear of 40-50 kts slowly decreases. Although latest guidance suggests numerous RW/TRW will hold off until after 06Z - with this potential initiation from a trailing vort max from the departed northern system sliding across the northern Midwest. Should these cells organize over our southern counties, rain and a few strong storms could linger towards dawn towards the I-70 corridor as shear values increase slightly pre-dawn. All possibilities considered, expect scattered showers and a few strong storms along the Ohio Valley and our far southern zones, likely starting during the evening. Cannot rule out isolated wind damage, although widespread severe storms are not expected. Likely a greater threat will be flood potential with slower storm motion and training/repeat cells over the same locations given the boundary`s very slow motion. A staunch precipitable water gradient over southern central Indiana should limit flood threat to far southern and southeastern counties. Light winds will oversee minimum temperatures ranging from mid 50s along the Upper Wabash Valley to low 60s across the US-50 corridor. Indianapolis will need to drop below 70F by 05Z to avoid at least tying the record high minimum for 5/22. && .LONG TERM (Thursday through Tuesday)... Issued at 304 AM EDT Wed May 22 2024 Thursday... An upper level wave south of the area will interact with a lingering surface front south of central Indiana on Thursday. Moisture will be lingering near the surface front, and the upper system will have some moisture with it. Across northern portions of the area, drier air will be around along with some influence from surface high pressure. Thus, will go with some likely PoPs across the south, closest to the wave and front, tapering down to dry PoPs across the far northwest, deeper in the drier air. Friday... A more complicated pattern will be around for Friday. Another upper wave to the south will bring another round of forcing to the area. Meanwhile, an upper system well to the northwest will have an accompany surface cold front approach the area during the day. Questions remain on timing and location of best forcing during the day. There could potentially be a split where highest PoPs are in the northwest and southeast forecast area, with the middle part of the area in a relative lull. However, confidence is too low to differentiate at this time, so will keep broadbrushed likely PoPs across the much of the area with lower confidence than usual. As the front moves in Friday night, another round of rain will move through, prompting likely PoPs again. Saturday... Generally quiet weather will rule on Saturday as high pressure briefly builds in. There could be some lingering showers in the morning, especially east. Blended guidance keeps low PoPs in the afternoon east, but confidence is very low in this happening. Sunday... A more potent system will move into the area on Sunday. The system will have good moisture with southerly flow in the warm sector of a surface low pressure system. This combined with the expected forcing from the upper wave should lead to rain across much of central Indiana into Sunday night. Of course, this far out, precise timing of the rain chances isn`t possible, and current timing could shift. However, it does appear that rain will fall at some point Sunday into Sunday night. Depending on the timing and eventual path of the surface system, strong to perhaps severe storms would be in the realm of possibility. Will have to keep a close eye on it. Memorial Day onward... The Sunday system will be way out on Monday, but there could be some lingering rain as the system exits. Will keep some low PoPs around. Into mid-week next week, the eastern USA will be under a broad upper trough with ridging across the western USA. Various waves moving through the trough could bring some rain, but timing and strength of these remains quite uncertain this far out. Will keep some low PoPs around for now. Temperatures will be a little cooler than normal in this setup. && .AVIATION (12Z TAF Issuance)... Issued at 655 AM EDT Wed May 22 2024 Impacts: - South-southwesterly wind gusts to 22-26KT at KIND thru 13Z - MVFR CIG possible at times this morning - Widely scattered SHRA/isolated TSRA near/south of KBMG after 21Z Discussion: MVFR ceilings are possible at times for a few hours this morning ahead of a weak cold front slowly crossing the region from northwest to southeast....with VFR otherwise expected into Wednesday night. VCSH will otherwise be the rule through the TAF period, with scattered SHRA/isolated TSRA possible near/south of KBMG after 21Z. Southwesterly winds earlier this morning will diminish while slowly veering to WSW/W today. KIND may have robust gusts to 20-25KT through 13Z. More reasonable flow is otherwise expected today with sustained winds around 9-13KT today...with winds diminishing early this evening while veering to the north. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Updike SHORT TERM...AGM LONG TERM...50 AVIATION...AGM