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000
FOUS30 KWBC 171110
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
710 AM EDT Wed Apr 17 2024

Day 1
Valid 12Z Wed Apr 17 2024 - 12Z Thu Apr 18 2024

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT LAKES, OHIO VALLEY AND WESTERN PARTS OF THE NORTHEAST...

Showers and thunderstorms tracking across the Ohio Valley may
produce periods of heavy rainfall. Much of eastern Ohio and western
Pennsylvania have Low FFG which does maintain an elevated threat
for excessive rainfall and local flooding concerns. Model consensus
has accumulations less than 2 inches across this area. Multiple
rounds of convection will track through eastern portions of
Pennsylvania and into New Jersey could reach 1 inch within areas of
low FFG indices, especially in the 3 and 6-hr FFG intervals. The
Marginal Risk area that was already in effect was maintained for
this period.

A non-zero threat also exists over portions of the Deep South as
well tomorrow afternoon and evening. Some weak low-level
convergence was noted on CAMs with a few members going more robust
on the convective threat in eastern MS over into central AL during
peak diurnal instability. There was not enough consistency for one
to prompt an additional risk area. Also, the rates expected would
not threaten current FFG intervals. Unless we get some significant
upgrade in the potential, this will remain outside any additional
MRGL issuance`s.


Campbell/Kleebauer


Day 2
Valid 12Z Thu Apr 18 2024 - 12Z Fri Apr 19 2024

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS AND MISSISSIPPI VALLEY...

A surface low pressure system and associated front will develop
across the Central Plains and advance toward the Mid-Mississippi
Valley and convection will fire off as the moist return flow from
the Gulf of Mexico drawls northward into the system. Locally heavy
rain will setup over Missouri and points southwest to central
Texas. The better concentration of the heavy rain will focus across
Missouri and surrounding locations. Recent rains have lowered some
of the FFG across this region and may have an increased
sensitivity to additional rain/heavy rain. A Marginal Risk area
covers part of northeast Texas to southern Missouri and western
Kentucky.

Campbell


Day 3
Valid 12Z Fri Apr 19 2024 - 12Z Sat Apr 20 2024

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY...

The low pressure system will continue to have its associated front
boundary draped across the Midwest and Plains during period while
dryline sets up from the Oklahoma Panhandle to the Big Bend area.
Convection is expected to be along and south of the front over the
Southern/Central Plains and Lower Mississippi Valley with the
higher QPF near/east of the dryline in west-central Texas. The
latest guidance varies quite a bit in regard to placement and how
much will fall however consensus does suggest the higher amounts to
focus mainly over Oklahoma and a sliver of Arkansas. The
environment may be supportive for 0.50+ inch/hour rates which in
turn elevated the risk for local flooding concerns. A Marginal
Risk area spans the Big Bend area northeast to central Arkansas.


Campbell


Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt