FOUS30 KWBC 070844 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
344 AM EST Fri Mar 7 2025

Day 1
Valid 12Z Fri Mar 07 2025 - 12Z Sat Mar 08 2025

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

Bann


Day 2
Valid 12Z Sat Mar 08 2025 - 12Z Sun Mar 09 2025

...A MARGINAL RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
CENTRAL GULF COAST...

There will be an increasing chance for showers and thunderstorms to
organize and become capable of producing rainfall rates in the 1 to
2 inch per hour range along portions of the central Gulf coast on
Saturday and Saturday night.

A fairly potent upper low will be making its way from the Southwest
U.S. into the Southern Plains by early Sunday morning. South to 
southwesterly low level flow ahead of the mid- level energy will 
start to draw moisture northward...with precipitable water values 
increasing into the range between 1.50 and 1.75 inches by Saturday
afternoon...although present indications are that the higher 
rainfall rates probably do not develop until the better upper level
support arrives and a well- defined cold front makes approaches 
the coast later in the day.

The 07/00Z suite of QPF guidance still focused parts of the Gulf
coast for mainly a low-end risk of excessive rainfall...which mirrored
the WPC deterministic QPF preference which gave least
consideration to the more northerly position of the GFS QPF
compared with other operational model runs...and offered strong
support to the placement of yesterday's Day 3 ERO.
Consequently...only minor changes were needed.

Bann


Day 3
Valid 12Z Sun Mar 09 2025 - 12Z Mon Mar 10 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE SOUTHEAST U.S....

The potent shortwave trough that brings the risk of excessive
rainfall along the Gulf coast on Day 2 will continue tracking
eastward from the Southern Plains towards the Florida panhandle or
southern Alabama by early Monday morning.. Moist southwesterly 
flow ahead of the system will have drawn an airmass with 
precipitable water values in excess of 1.5 inches over portions of 
the northern Florida peninsula and adjacent parts of Georgia. The 
WPC deterministic QPF forecaster still gave less weight to the 
GFS...resulting in little need to make more than some cosmetic 
changes to the placement of yesterday's Day 4...before the bulk of 
the rainfall from this system moves offshore.

Bann

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