686
FOUS30 KWBC 020824
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
424 AM EDT Tue Jul 2 2024

Day 1
Valid 12Z Tue Jul 02 2024 - 12Z Wed Jul 03 2024

...THERE IS A SLIGHT RISK FROM PORTIONS OF THE UPPER MIDWEST TO THE
PLAINS...

...Upper Midwest through Central Great Plains...

Still on track for heavy rainfall over portions of Iowa and Missouri
as well as a small portion of neighboring states given plenty of
synoptic scale forcing and upper level jet support as well as
plenty of deep layered moisture. There still appears to be some
potential for training and backbuilding...so concern for flash
flooding is towards the high end within the Slight category. The
potential for cold pools helping to keep convection moving and the
fact that overlap with areas hard hit by previous heavy rainfall to
the north appears less than it was on Monday. We will continue to
watch for trends in subsequent high resolution model runs.

...Southeast...

A Marginal Risk is maintained over the Florida Panhandle and
southern GA in proximity of a slow moving cold front. Rainfall
still expected to be lower than what fell on Monday, but the
plentiful Gulf moisture allows for the potential for very high
rainfall rates and localized large rainfall amounts.

...Southwest...

Again maintained a Marginal over eastern AZ/western NM with a
suppressed Monsoonal flow day as troughing to the north shunts the
ridge axis farther east to the lower Miss Valley. Elevated moisture
is limited to the southern portions of those states and remnant
stratus from Monday night activity may further suppress Tuesday
activity.|

Bann

Day 2
Valid 12Z Wed Jul 03 2024 - 12Z Thu Jul 04 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE MIDWEST TO THE GREAT PLAINS...

...Midwest to Great Plains...

A cold front from a passing trough over the northern tier of states
stalls over KS/MO by Wednesday morning, providing renewed focus
for thunderstorm development from eastern KS through southern IL
with potential for heavy to excessive rainfall...with only minor
adjustments needed to the placement of the Slight Risk already in
place.

The frontal zone extends east over the rest of the Midwest to the
eastern Great Lakes where a Marginal Risk is maintained with some
areas of the Northeast trimmed with the 02/00Z QPF consensus being
farther west.

Over the northern Plains, the next trough axis enters the northern
High Plains Wednesday night with activity over the Dakotas
warranting a Marginal Risk.

...Southwest...

A trough axis from the next reinforcing wave allows anomalous
moisture over AZ/NM to spread northeast to the southern High Plains
on Wednesday which warrants maintenance of the Marginal Risk with
some trimming based on the 00Z consensus.

Bann

Day 3
Valid 12Z Thu Jul 04 2024 - 12Z Fri Jul 05 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE CENTRAL US...

...Upper Midwest to Mid Mississippi Valley...

Mid and upper level height falls across the upper midwest dropping
into a region with anomalously moisture rich environment should
result in increasing chances of showers and thunderstorms on
Thursday and Thursday night...with embedded shortwave energy and
divergence aloft from a digging upper jet focusing and supporting
areas of heavy rain and chances for excessive rainfall from intense
rainfall rates during the latter part of the outlook period.

...Mid-Mississippi Valley eastward...
Moisture should start to be transported from the Mid-Mississippi
Valley eastward across the Ohio/Tennessee Valleys into the Mid
Atlantic region as flow aloft responds to the digging trough over
the nations mid-section. Some guidance generates convection that
may challenge flash flood guidance. There was already a Marginal
Risk introduced and saw little reason to make more than minor
adjustments in placement.

Bann


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