WPC Day 3 Excessive Rainfall Outlook
Risk of 1 to 6 hour rainfall exceeding flash flood guidance at a point
Updated: 0844 UTC Wed Oct 17, 2018
Valid: 12 UTC Oct 19, 2018 - 12 UTC Oct 20, 2018
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
427 AM EDT Wed Oct 17 2018
Valid 12Z Fri Oct 19 2018 - 12Z Sat Oct 20 2018
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
NORTHEAST AND SOUTH TEXAS...
As the energy from the mid-level low, which was once anchored
across the desert southwest, has been absorbed into the digging
northern stream trough, the mid level moisture axis from the Gulf
will now start to veer to the northeast. This combined with the
approaching surface front from the northwest will allow the axis
of precipitation to migrate eastward. The best moisture flux, lift
and surface convergence seems to align somewhere in northeast TX.
While areal averages are only expected to top out around 1-1.5
inches, this area has received quite a bit of rainfall as of late.
Lower FFG and the possibility of locally higher QPF instigated
the MRGL in this region.
Meanwhile, along the coast there is continual moisture feed
(precipitable waters of 2+ inches) with an instability axis
lagging just onshore. This will result in convection that could
train over the same region right along coast, collocated with
surface convergence. Areal averages of 1.5-2 inches would likely
not promote flooding concerns within this region, but given
previous days potential convective activity, it could cause
issues. Therefore, a MRGL was also introduced in this area.
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt