Day 58 — 2026-04-27. A major widespread storm arrived late in the day. The pre-storm picture is recession from Event 7; the post-storm picture is the leading edge of what looks like Event 8.
Today's precipitation came in two distinct phases. Most of the day was dry across the watershed during the recession from Event 7. A large, intense storm system arrived late evening (Apr 27 ~21:00 CDT / Apr 28 02:00 UTC) and is still active at end-of-day cutoff.
Spatial pattern: Heavy rain concentrated in the southern/eastern half of the watershed, with the upper watershed (Boxley/Ponca/Pruitt) largely missed.
| Zone | 24hr QPE | Peak 1hr | Max 6hr |
|---|---|---|---|
| Boxley | 0.171" | 0.094" | 0.103" |
| Ponca | 0.021" | — | 0.046" |
| Pruitt | 0.008" | — | 0.012" |
| St. Joe | 0.453" zone-avg | 0.68" | 0.842" |
| Richland | 0.461" | 0.391" | 0.474" |
| Bear Creek | 0.595" | 0.681" | 0.741" |
| Harriet | 0.560" | 0.560" | 0.613" |
| Ungauged | 0.478" | 0.700" | 0.848" |
HUC12 hotspots (24hr totals): - Cave Creek (0305): 0.823" ← St. Joe sub-basin - Rocky Hollow (0402): 0.842" ← St. Joe sub-basin - Long Creek (0505): 0.848" ← ungauged - Shop Cr (0301): 0.776"; Outlet LB (0308): 0.600"; Lick Cr (0304): 0.583"; Calf Cr (0401): 0.621" - Outlet Bear Cr (0404): 0.741" with 0.681" peak 1hr - Brush Cr (0405): 0.593"; Dry Cr (0406): 0.613"; Tomahawk (0407): 0.545"; Water Cr (0408): 0.548"; Spring Cr (0409): 0.500" — Harriet zone widely 0.5-0.6" - Headwaters LB (0102): 0.282" but Shop Creek (0101): 0.545"
The storm is intense: 0.5-0.8" peak hourly rates in many HUC12s indicate convective cores. Note that peak 1hr times are 02:02-04:02 UTC = 21:02-23:02 CDT, meaning rain started at end of the data day and is presumably continuing into Apr 28.
Antecedent: Wet. 7-day antecedent in the affected zones is now 1.0-1.4" thanks to Event 7. This is high-amplification territory.
The data day primarily captures continued recession from Event 7, with the late-evening rain pulse just beginning to register at one gauge.
| Gauge | Start (00:00) | End (23:30) | Net | Notes |
|---|---|---|---|---|
| Boxley | 2.70 ft | 2.58 ft | −0.12 ft | Pure recession |
| Ponca | 197 cfs | 173 cfs | −24 cfs | Pure recession |
| Pruitt | 4.55 ft / 337 cfs | 4.38 ft / 284 cfs | −0.17 ft / −53 cfs | Pure recession |
| St. Joe | 5.29 ft / 991 cfs | 5.06 ft / 857 cfs | −0.23 ft / −134 cfs | Reversal at 21:00 |
| Harriet | 5.14 ft / 1,250 cfs | 4.91 ft / 1,050 cfs | −0.23 ft / −200 cfs | Slight reversal at 22:30 |
| Richland | 1.98 ft | 1.85 ft | −0.13 ft | Pure recession |
| Bear Creek | 2.36 ft / 30.1 cfs | 2.33 ft / 27.8 cfs | −0.03 ft / −2.3 cfs | Step up at 21:30 |
Notable: St. Joe reversal. St. Joe declined steadily to 829 cfs at 21:00, then jumped: 857 → 868 → 862 → 868 → 868 by 22:45. This is a +39 cfs / +0.07 ft rebound during a window when the gauge had been falling ~6 cfs/15min. This is not a random glitch — it's the first signal of the new storm reaching St. Joe, almost certainly via the Cave Creek (0.823") and Rocky Hollow (0.842") cores that drain near the gauge. Lag from peak rainfall (~21:02 CDT) to first rise (~21:15) is suspiciously short — likely indicating saturated soils flashing very quickly given wet antecedent, plus those HUC12s are immediately upstream of the gauge.
Bear Creek step-up at 21:30: height jumped 2.31 → 2.34 ft (+0.03 ft) and discharge 26.3 → 28.5 cfs in 15 min. Coincident with peak 1hr in Outlet Bear Cr (0.681" / 0.681" peak hr). Lag is very short again — but this is preliminary, not the actual peak response.
Harriet small bump at 22:30: 4.89 → 4.91 ft, discharge 1,030 → 1,050. Could be propagation noise or beginning response; too early to call.
The new event is too young for clean transfer-ratio analysis. Preliminary observations:
Recession-phase propagation continued normally through the day before being interrupted by new rain. No useful new propagation timing yet — Event 8 is just beginning.
Event 7 recession continues and is now being terminated by Event 8. Three days post-peak summary:
Event 8 incipient. With watershed-wide 0.5-0.85" already deposited overnight and the storm presumably ongoing, this could be substantial. Notable that Boxley/Ponca/Pruitt have been bypassed so far — this is fundamentally different from Event 7's watershed-wide pattern. Right now Event 8 looks like it may be primarily a St. Joe + Richland + Bear Creek + Harriet event, similar in spatial signature to the Mar 4-5 2024 reference event but smaller in magnitude (so far).