Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
406 AM EDT Wed Jul 28 2021
 
Day 2
Valid 12Z Wed Jul 28 2021 - 12Z Thu Jul 29 2021 

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS 
OF ARIZONA...

...Southwest into the Northern Rockies...
Monsoonal moisture will continue to cause flooding concerns for 
portions of the Southwest northward into the Northern Rockies. Low 
FFG and periods of rain leading up to this period all lead to 
concerns for flooding. Both the Slight Risk area and the Marginal 
Risk area were adjusted to account for latest model guidance and 
updated QPF forecast. PW values continue to exceed 1.00 inches 
with anomalies reaching 2.5-3 std deviations above climo for these 
areas.

...Northeast south through the Ohio Valley...
The upper trough will continue to bring periods of heavy rains to 
this region with latest guidance showing signals of 1 to 3 inches. 
Much of this area sits near 150-400% of normal for precipitation 
in the past few weeks and with antecedent conditions priming soils 
even more, flooding could be of concern for this period. PW values 
sit near 1.5-1.75 inches for much of this area during this time. 

...Eastern Florida coastline...
Tropical moisture will continue to pump into the region creating 
periods of heavy rainfall. PW values remain near 2.25 inches 
during this timeframe with latest model guidance showing signals 
of 2 to 4 inches. Urban areas will be the most susceptible to 
flooding during this time period.

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