Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1120 AM EST Sat Feb 8 2025
Day 1
Valid 16Z Sat Feb 08 2025 - 12Z Sun Feb 09 2025
...16Z Update...
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR MUCH OF WEST
VIRGINIA...
No changes were made to the ongoing Marginal Risk area across West
Virginia. Recent rainfall has made the soils there saturated.
However, rainfall rates have all been at a half inch per hour or
less across the area. Thus, any flooding has been from areal river
rises as rates have not been high enough to cause flash flooding.
A slow-moving warm front in the area has been the cause for the
rainfall. The rain will lift north this afternoon as the state gets
into the warm sector. This evening, the cold front will move
through that could cause heavier rain, albeit with fast moving
convection. The greatest threat for isolated flash flooding will
occur with any training heavier showers, and a thunderstorm or two
can't be ruled out. The front will sweep through by around
midnight, ending the flooding threat due to rainfall, though rises
from draining streams and creeks will continue through the night
and into the day on Sunday.
Wegman
...Previous Discussion...
...West Virginia...
Strong N-S quasi-zonal mid and upper level flow will be perturbed
a bit during Day 1 (12Z Sat-12Z Sun) as a 150+ kt upper level jet
streak traverses the Upper Midwest and Ohio Valley, while a flat
500 mb vort lobe pushes across the Lower Great Lakes. Broad-scale
exit region forcing associated with the upper jet axis will surge
southwesterly low-level inflow ahead of the surface frontal wave,
with 850 mb moisture flux anomalies peaking between 4-5 standard
deviations above normal later this afternoon into Sat night, while
TPW values peak around 1". Robust synoptic-scale support and low-
level moisture transport will be offset somewhat by the weak
elevated instability, with MUCAPEs generally less than 500 J/Kg.
Nevertheless, even though not advertised on the latest (00Z Sat)
HREF, the aforementioned dynamic and thermodynamic ingredients will
be sufficient for spotty hourly rain rates of 0.5"+ and 3-hourly
rates of 1.0"+, with localized event totals between 1.5-2.0"+.
Current 3-hr flash flood guidance values remain quite low (1" or
less) across the outlook area, which includes much of WV. Despite
the lack of instability, the low FFG values could be exceeded over
isolated areas with 2 consecutive hours of 0.5"+/hr rainfall rates.
Since the soils in these areas are saturated, and the terrain is
rugged, we have maintained the Marginal Risk area for much of WV
(outside of its northern or eastern Panhandles).
Hurley/Roth
Day 2
Valid 12Z Mon Feb 10 2025 - 12Z Tue Feb 11 2025
The probability of rainfall exceeding flash flood guidance is less
than 5 percent.
Hurley
Day 3
Valid 12Z Mon Feb 10 2025 - 12Z Tue Feb 11 2025
The probability of rainfall exceeding flash flood guidance is less
than 5 percent.
Hurley
Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt