FOUS30 KWBC 170757
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
357 AM EDT Fri Oct 17 2025

Day 1
Valid 12Z Fri Oct 17 2025 - 12Z Sat Oct 18 2025

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

Oravec


Day 2
Valid 12Z Sat Oct 18 2025 - 12Z Sun Oct 19 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NORTHWEST 
ARKANSAS, ACROSS SOUTHERN MISSOURI INTO SOUTHERN ILLINOIS...

The latest models remain in good agreement on the overall
sharpening of the mid to upper level trof across the mid section of
the nation Saturday into early Sunday. Well defined upper difluence
likely between the northern stream vort moving east southeast
across the Central Plains and the southern stream vort moving east
northeast across the Southern Plains. PW values will increase to 1
to 2+ standard deviations above the mean in this broad upper
diffluent axis from eastern portions of the Southern Plains,
northeastward into the Mid MS Valley and Great Lakes, along and
ahead of the associated eastward moving frontal boundary. Model 
consensus is for a broad area of moderate to heavy rainfall amounts
in this axis. All of this region has been very dry with relative 
soil moisture low, low stream flows and subsequently FFG values 
very high, which will be a detriment to widespread runoff issues. 
The previous slight risk area was shrunk considerably, focusing it 
where the HREF and RRFS means show higher probabilities for 1 and 
2"+ amounts in the 12 hour period from 12Z Sat Oct 18 to 00Z Sun 
Oct 19 from northwest AR, across southern MO into southern IL. This
region also corresponds to where the relative soil moisture is not
as low as points farther to the northeast and southwest, although 
overall, still low. There may be a period of training of cells in 
the slight risk area during the first half of the day 2 period, 
before the convection begins to accelerate to the east and 
southeast during the second half of day 2. The previous marginal 
risk area was also decreased significantly, narrowing the eastern 
extent through the OH and TN Valleys.

Oravec


Day 3
Valid 12Z Sun Oct 19 2025 - 12Z Mon Oct 20 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE EASTERN
GREAT LAKES INTO THE CENTRAL APPALACHIANS...

The amplifying mid to upper level trof across the mid section of
the nation day 2, will continue to accelerate eastward day 3,
becoming increasingly negatively tilted as it moves through the OH
Valley, Central Appalachians, Mid- Atlantic and eastern Lakes. The
fast eastward movement will continue to be a limiting factor for
very heavy rainfall amounts and any widespread runoff issues. While
FFG values are much lower across the eastern Lakes into the Upper
OH Valley and Central Appalachians than areas farther south and
west during the day 2 period, the aforementioned progressive
nature of the day 3 system should preclude most areas exceeding 
FFG values. No changes made to the previous marginal risk area from
the eastern Lakes, south into the Upper OH Valley and Central 
Appalachians. 

Oravec
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