A rare Sunday afternoon blog for you as we wait and see what could unfold locally and regionally overnight. A dynamic and strong storm system will be moving through the Plains today and tomorrow…exiting the region tomorrow afternoon and sending air pressure levels way down in the process. See all the blogs this week referring to that.
This system will likely have the worst weather down towards the southern Plains into OK but for us…the effects are a bit trickier to figure out. Storms that fire and are severe down through OK will be racing towards the NE and ENE at close to 60 MPH or faster being propelled by VERY strong winds above us. What shape their in by the time they get to us is a major question.
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Forecast:
Today: Generally cloudy and cool for most of the day with temperatures mainly in the 40s through the day then warming into the 50s this evening. There may be a few showers out there later today or this evening. Winds slowly increasing.
Tonight: A line of thunderstorms and heavy rain should race through the region between 12AM and 3AM or so. Temperatures at that point will be in the mid to upper 50s. Those storms may briefly have 40-70 MPH wind potential IF the strong winds just above the surface can work their way to the ground. Still a big if but that is the main threat for the region as a whole.
Tomorrow: A brief morning shower is possible at daybreak, especially on the north side but overall clearing towards afternoon and mild with highs back into the 50s. Very windy as well with gusts to 50 MPH possible.
Tuesday: Partly cloudy and warm with highs well into the 50s…and potentially 60s if a warm front moves towards the north of the Metro
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Discussion:
Let’s start with the SPC outlook which has been trending more and more northwards regarding the severe weather risks. This of course is no surprise to me because we’ve been talking about the main threat of strong winds from this system all week long really. Frankly I was surprised it’s taken this long.
We are in a level 2 risk…with level 3 risks farther south of the Metro towards Butler and Clinton as of this late morning update.
There is a rare for February level 4 risk into OK…
This moderate risk in OK is mainly connected to strong winds…and there is the potential of a derecho to come together down there and with the wind field aloft being so aggressive…80-110 MPH winds are possible down there. Some stronger tornadoes are possible, mainly in SW OK it appears.
The set up though is a race…as I mentioned in Friday’s blog…there is the issue of getting things primed to fire…and for folks down there they’re waiting on dew points to come up…
Remember in Friday’s blog I showed you the rich gulf moisture hugging the coastal region of TX…and all the north winds in the State. Well now the winds are from the south…the rich Gulf moisture is advancing northwards at a good clip. The green line shows dew points in the 60s
There are a TON of clouds down there are are starting to break up…this will allow instability to increase pushing northwards towards northern TX and OK later today and this evening.
As this occurs…we wait for our storm to enter the picture…at the surface this afternoon it’s developing and deepening across SE CO. The map below should auto update
The black lines are isobars or lines of equal pressure.
As that occurs the strong upper level storm comes into play. This is the one that’s been rewriting weather history books in CA these last couple of days bringing snow to places that haven’t seen seen in recent memory as well as lots of graupel and flooding rains.
It’s moving through AZ today…
Over the past 72 hours it has snowed…a lot there.
There has been a lot of flooding as well…which is receding to some extent today with improving weather but additional storms are likely in the Mountains this week out towards the Sierras with 5+ feet of snow coming!
For us…we track both the surface storm and the upper level storm that will both be strengthening as they come into the region overnight
Notice how the upper level storm deepens (the colored contours) and the surface storm follows suit…it deepens to apprx 982 mbs in SE Nebraska
The HRRR model actually brings this down to 978 mbs in NW MO…just incredibly low and means your home barometers up in NW MO may have readings close to or below 29.00″…29.92″ is considered about average.
Pressure readings for the Metro may drop to 29.03″ to 29.12″…rare for their extreme lowness.
Migraine suffers have been warned for days on my newscasts about this intense low atmospheric pressure…
As the storm aloft and at the surface approaches…strong thunderstorms will be coming up from the SW of the area…the HRRR model shows this moving into the Metro just after 12AM…they will be flying at more than 60 MPH and if they were moving at more than 70 MPH it wouldn’t surprise me at all.
So the thought process is that storms fire in the western Plains…move towards the ENE…here is the HRRR model showing the storms coming together by about 5PM out there…
Here is a close up…
This model perhaps showing the strongest storms more towards KC and southwards…but I don’t have 100% confidence that that is the playout with a wind field aloft that only 5,000 feet up looks like this.
This is the point I’ve been hammering on for the week…this is a dynamic storm and dynamic storms can create unusual weather. This type of fast moving squall line at this hour of the night in late February is VERY unusual.
The real question is CAN this storms coming…tap into the strong winds above us, despite the possible lack of surface instability. There will be some instability aloft though and IF the storms maintain themselves there may be numerous severe thunderstorm warnings in the area, especially from the Metro southwards.
Strong winds are the main threat…although I guess some smallish hail wouldn’t be too surprising.
Again the timing of this…late February…middle of the night…most may be sleeping…2 days after ice was an issue…may catch many by surprise IF they haven’t been paying attention to the forecasts this week…especially if they’ve watched maps not even putting KC in the risk area. Again that was the reason I never showed those maps this week. That’s why I’ve been banging the drum on the stronger wind risk for this almost all week long.
Thankfully there are no leaves on the trees…so that may help in a sense.
I won’t be shocked if this is just fast hitting rains…we may get 1/4-1″ of rain in 2 hours, with the strongest winds staying above the surface and harmlessly passing by (unless you’re in a plane)…but those strong winds above the surface won’t take much to be transported to the ground by the heavy rains dragging them to the ground.
Jacob will update you later this evening after racing.
Joe
