Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1028 AM EST Sun Jan 12 2025

Day 1
Valid 12Z Sun Jan 12 2025 - 12Z Mon Jan 13 2025

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

...16z update...
Forecast remains on track based on observations and 12z Hi-Res/HREF
guidance. The forcing and ascent pattern is solid within the right
entrance of the 150kt jet the Red River Valley. This supports the
divergence and northward surge of low-level wind response to bring
the surface wave and moisture near the LA coast this afternoon.
However, CAMs still indicate maximum MUCAPE in the 250-500 J/kg for
any elevated cells to develop. So narrower cores, fast cell motions
may translate across urban centers in SE LA; but that is likely the
bare minimum of flooding risk/concern through the forecast period.
HREF probs, still generally remain below 1"/hr.

Gallina

~~~~~Prior Discussion~~~~~

...Louisiana Coast...
A frontal wave spawned by an upper level disturbance moving between
a Southwest U.S. upper level low and a subtropical ridge near Cuba
is expected to bring precipitable water values up to 1.5" over
portions of the central Gulf Coast as early as late this afternoon
in response to low level flow becoming southwesterly at 20-35 kts.
Despite the moisture transport into the area...the overall risk of
excessive rainfall appears to be held in check by meager
instability and the progressive nature of the system. The 12/00Z
HREF guidance maintained continuity with the 11/12Z run that show
the probability of 0.5"+ totals don't persist anywhere along or
near the Louisiana coast for more than an hour or two. There was a
slight southward shift and a subtle decrease in rainfall amounts in
the guidance which resulted in decreasing neighborhood
probabilities for 2+ inch rainfall amounts compared with the
previous runs.

Bann

Day 2
Valid 12Z Mon Jan 13 2025 - 12Z Tue Jan 14 2025

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

Bann

Day 3
Valid 12Z Tue Jan 14 2025 - 12Z Wed Jan 15 2025

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

Bann


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