FOUS30 KWBC 240815
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
415 AM EDT Thu Oct 24 2024

Day 1
Valid 12Z Thu Oct 24 2024 - 12Z Fri Oct 25 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS=20
OF THE MIDDLE MISSISSIPPI VALLEY...

Introduced a Marginal Risk for portions of the Middle MS Valley,
from northwest IL and southeast IA into northern MO (and adjacent=20
portions of far northeast KS). Strengthening southwesterly low-
level flow (850 mb) to 40-50 kts this evening will usher in PWATs=20
to near 1.25" (well above the 90th percentile, per SPC sounding=20
climatology), along with sufficient instability (ML CAPE 1000+
J/kg) and forcing (potent shortwave trough crossing the Central
Plains) for convective development. Strong vertical shear (~50=20
kts) with idealized curving hodographs will likely favor discrete=20
convection (with both the mean flow and bunkers right vectors=20
favoring storm motions of 20-30 kts), and despite relatively low=20
PWs (particularly compared to warm season convection) any
supercells will likely be capable of 1-2"/hr rainfall rates (per=20
40-km neighborhood HREF probabilities for 1"/1-hr exceedance of=20
40-50%). While 1-2" totals should be well tolerated by soils (and=20
largely beneficial, given dry antecedent conditions), localized=20
training could result in too much rainfall (2"+) too quickly (in a=20
matter of 2-3 hours). Given this threat, an isolated instance or=20
two of flash flooding is possible.=20

Churchill


Day 2
Valid 12Z Fri Oct 25 2024 - 12Z Sat Oct 26 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Churchill


Day 3
Valid 12Z Sat Oct 26 2024 - 12Z Sun Oct 27 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Churchill


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/94epoints.txt__;!!DZ3fjg!6CeD7NrPF0Sn5y0Oo45azqn821JBx8H-pTqTnaTsMelQ=
7fMErAlxIapHNJg9dZen9I3xjAxRjWtJ9wGNlAPlZKLewIo$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/98epoints.txt__;!!DZ3fjg!6CeD7NrPF0Sn5y0Oo45azqn821JBx8H-pTqTnaTsMelQ=
7fMErAlxIapHNJg9dZen9I3xjAxRjWtJ9wGNlAPlxTc_RM0$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/99epoints.txt__;!!DZ3fjg!6CeD7NrPF0Sn5y0Oo45azqn821JBx8H-pTqTnaTsMelQ=
7fMErAlxIapHNJg9dZen9I3xjAxRjWtJ9wGNlAPluNH43xs$=20

=3D =3D =3D
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