Latest SPC OUTLOOK for Tuesday/Tuesday Evening:
We are all however in the risk for severe storms with this event.
This afternoon---it will be quite mild for January 28th with temps nearing 60 in spots later. There are s few downpours out there now in the SW flow, but the shear is well to our west--so no worries on severe this afternoon.
That will change Tuesday night.
TIMING: It has slowed a bit on the GFS/NAM...it looks like 9z is the target time...which is 4am EST. However, if the squall-line taps into the winds aloft---the timing may speed up a bit. So we remains with a midnight Wed to sunrise Wed morning as the main period of the threat from one end of our viewing area to the other.
WINDS: This system will certainly have the wind with it. I will say the models have eased a bit on the winds aloft compared to yesterday---but still quite potent.
Both showing the risk for potential winds translated to the ground on the order of 60 to 70 mph.
INSTABILITY: As usually the case in winter, it is low. We have plenty of moisture moving in---just lack of solar heating. Still, CAPES are high enough (roughly 200 j/kg) that the clouds can build up to the level of tapping into the winds aloft posted above.
THREATS: Heavy rain. Lightning. Damaging winds in the range of 60-70 mph possible. And the NAM EHI scans below show some risk for isolated tornadoes embedded in the line. They would be small/brief---but still have to be watched.
SUMMARY: This is a typical winter severe weather threat. I mentioned yesterday that the storms have a risk to be elevated somewhat to protect us from the strong winds being pushed to the surface. That is still possible giving the late night timing---but I would strongly caution that is not certain---so we need to prepare for a high wind event regardless. Even before and after the storms arrive---it will be windy with winds gusting to 40 mph at times. There will be a threat of power outages even with those winds. Rain amounts likely to exceed 1.00" in spots. Any training of the storms could push a few of u closer to 2.00".
SHOULD YOU BE CONCERNED?
This won't be a huge severe weather outbreak, but there is concern for those high winds to push downward. We have a wet ground still in place, so it wouldn't take much to take down a tree. The timing is bad with overnight/early morning. Rush hour Wednesday morning may be messy with flooded roadways and traffic light outages---so plan for extra time. Just have your NOAA radios plugged in. We will be here all night long watching it for you guys. Let's hope the ingredients don't line up as indicated---and this weakens. We have seen that happen many times before certainly.
Temps will crash on Wednesday...but they will battle solar heating too. So it may be a gradual crash at first...and speeds up near sunset. It will be at that point that we cool down aloft enough that we may see the changeover to snow. GFS hints at around 7pm.
There looks to be a comma-head on the back side of this low. That will graze southern MO, into IL/IN and then into OH. How far south it reaches will determine any snow from that. It would be our only shot at minor accumulations. Otherwise---nothing to talk about with this snow chance.
The first one is slated for late Thursday/early Friday. It has trended weak the past several runs. It has not entered the grid yet of the upper air network---so I don't think the models fully have this one pegged. Nevertheless--it looks light...but timing near the morning rush Friday will have to be watched for slick spots.
The next clipper actually looks stronger...and colder ...for Saturday. EURO especially spits out advisory level snow for the region. GFS is a bit warmer with the profile...and hints at a mix. Still early yet on that one. But something to watch.
That is it for now as the severe storm threat needs our attention the next 36 hours. Then we will talk about wintry issues.