Chris's Corner - Conditional Risk for Isolated Severe Storms

insert quote hereIn coordination with LSX/St. Louis, MO forecast office, a Moderate

Risk area was introduced for portions of eastern MO with this late

morning update. Much of the guidance continues to indicate a

second round of training convection, which is expected to be a bit

more prolific with rainfall totals than the area dying out over

central MO currently. Using this morning as precedent, where there

were scattered instances of flash flooding, this second round is

likely to produce similar impacts. The good news is that the area

expected to be impacted with flooding rains tonight will be

displaced to the east just enough such that there is only limited

overlap with the rainfall that occurred overnight last night.

There remains considerable uncertainty as to the level of impacts

in the St. Louis metro itself, as any notable eastward deviation

of the line of storms could result in significant impacts to the

city itself. For now, will stick with the guidance consensus that

the heaviest rains will remain just west of town, though that will

certainly bear watching. It's worth noting that the latest HRRR

guidance does bring the axis of heavier rains into town, but is a

fair bit weaker in total rainfall than both its predecessors and

other current guidance. Expect there will be a bit better upper

level forcing tonight, and the west-southwesterly LLJ will be

pumping more moisture into the region tonight as compared with

last night, so the expectation of greater impacts is well-founded.