Thursday, March 14, 2019

Current Conditions at Sanborn Field
Wind Advisory until 7pm




 
Thursday Night -  Mostly cloudy with a good chance for showers. Low 32-36.


 
Friday - Partly Cloudy. High 42-46




Friday Night - Partly Cloudy. Low: 28-32




Saturday - Sunny.  High: 48-52.
    



Sunday - Partly Cloudy. High: 50-54



Thanks to IconArchive.com for the icons!


Discussion:

Hold onto your hats because today has been a breezy one!  We are under a high wind advisory until 7:00CST tonight.  We expect to see winds die down into tomorrow as the center of low pressure that is currently to our north moves farther east.  Overnight we do have the possibility for a few showers but we aren't expecting to see any snowfall as surface temps are staying above freezing.  Tomorrow looks to be a bit chillier than what we saw today as our winds shift to the northwest bringing in that colder air.  Tomorrow night we find ourselves wedged between two systems, a high pressure system over northwest Texas and that low pressure system moving over the Great Lakes.  This will cause us to have strong winds Friday night and keep our flow out of the northwest.  This will continue to drive in those colder temperatures into the weekend. Saturday and Sunday look to remain dry as we fall under the influence of the high pressure system that will settle over Arkansas.
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Forecasters: Doll, Meyers, and Bongard
Issued: 4:11 p.m.March 14, 2019

Technical Discussion (The nerdy stuff we are discussing in class!)
Smooth sailing ahead this coming weekend with spring knocking right on the front door. Currently we find ourselves in a high wind advisory until 7:00CST as we sit on the south side of a low pressure system slowly moving over central Iowa. In terms of model agreement both GFS and NAM has the system keeping on the same track moving northeasterly into Wisconsin overnight. The back side of this system brings the cold conveyor belt as well as colder temperatures and possible precipitation. With sounding comparisons, GFS keeps the surface-lower levels dry with a saturated level right above that around 850mb while NAM has us more saturated from 800mb-700mb and brings us snow overnight. We don't see the lower-surface levels getting cold enough for it to stay snow to the ground however we do agree with NAM on the system getting deep enough to reach us all the way from Wisconsin. 

Friday brings a lot of cold air advection throughout the day from the northwest keeping temps low and the atmosphere dry through the mid-lower levels. A high pressure system sitting over northwest Texas and a low pressure system above us over the Great Lakes keeps us sandwiched right in between the two systems. This gives us strong winds and cold air from the northwest. At the 250mb level, we see an incoming ridge over Montana that combines with the Tropic Jet and gives us confluence and a jet max over Oklahoma. The post frontal regime will be evident throughout the majority of Friday until officially moving out Friday night keeping conditions clear and cold. 

Saturday keeps the same pattern with the flow at 250mb continuing east at a steady pace throughout the day. We do see a band of vorticity to our north through Minnesota with the outgoing trough but we remain in the clear at 500mb. Looking at the GFS model, we remain mostly dry through the low-mid levels. Comparing sounding models however, GFS keeps us in a more zonal flow through later Saturday night while NAM swings our winds to the south at the lower levels and keeps us a bit more moist. At the 700mb level for NAM, it showed Missouri receiving moisture from the northern trough bringing possible cloud cover but no precipitation. We decided to lean more towards the GFS model as we didn't see a solid source for the incoming moisture. 

Sunday remains mostly the same with the flow at 250mb still continuing east. Vorticity at 500mb creeps closer to mid Missouri but only reaches southern Iowa. We do get a bit more moist at the 700mb level from some northwesterly flow but remain stable throughout the rest of the levels. The high pressure system we've seen all weekend retreats back south a bit over southwestern Arkansas. Looking at possible surface temps we do see a decent boundary starting in northeastern Illinois that extends all the way to southwest Missouri. This is due to the trough to our north shifting our winds from the south in the morning to northeasterly in the afternoon. This will keep our temps low with minimal cloud cover.

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