Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
455 AM EDT Thu Jul 4 2024
Day 2
Valid 12Z Fri Jul 05 2024 - 12Z Sat Jul 06 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER MUCH OF THE
SOUTHERN AND EASTERN U.S....

At least scattered convective development is likely along and ahead
of a cold front stretching from TX into New England. PWs are
forecast at or above the climatological 90th percentile over most
of this frontal zone...with upwards of 2000 j/kg of CAPE possible
along the extent of the front. Enough mid level troughing and
upper jet support to drive decent convective coverage as well. So
looking just simply at convective coverage, instability and PWs,
would support localized areas of heavy rainfall and flash flooding.
This assessment is also supported by the CSU machine learning ERO
which depicts a broad Marginal risk. Not seeing much in the model
QPF fields or environmental fields to really indicate where/if any
more organized and higher end rainfall event could occur. Instead
indications are that flash flood concerns generally stay isolated
in nature...confined to where heavy rates overlap an urban or other
sensitive area...or where cell mergers result in a locally
increased duration of higher rainfall rates. Would not be surprised
if somewhere within this broad risk sees Slight risk type
coverage/impacts...but at this lead time we do not have the
confidence to pinpoint exactly where.

Eastern NM should also see an uptick in convective coverage
Friday, with post-frontal upslope flow helping aid in development.
This is also a region where a focused Slight risk may eventually
need to be considered.

Chenard

Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt