Current Conditions at Sanborn Field 

Friday Night: Partly cloudy. Low: 64

 

Saturday: Scattered AM clouds. High: 90

Saturday Night: Partly cloudy.  Low: 70

 

Sunday: Partly cloudy. High: 92 

 

Sunday Night: Clouds decreasing overnight. Low: 71

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Discussion:

Warmer weather will be staying as the trend for the rest of the weekend with a partly cloudy sky holding strong. If you were looking for another pool day, this weekend would be a great hit! Central Missouri could see a splash of rain in the early morning hours on Sunday, but any chances once the sun comes up to say hi are little to none. A partly cloudy sky will be staying in attendance for the rest of the weekend as well continuing into early next week.

- Labit

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Forecasters: Macko, Labit, Allen

Date Issued: 09/16/2022 5:00 PM CDT

Technical Discussion:

 

This weekend's forecast was developed using a blend of the NAM, the GFS, and the NBM, with the greatest influence from the NAM. Evaluation of the mandatory levels in the NAM and the GFS described very different stories for Saturday into Sunday night. It is during this time period when forecast confidence decreases considerably. Consequently, the main issue that the forecasters experienced was determining the chance for showers and thunderstorms late Saturday evening into Sunday morning. 

The upper-level jetstream was found to be hugging the California coastline as of Friday afternoon. This jetstream is expected to creep eastward over the weekend, but Missouri will remain completely outside of its reign until sunrise on Sunday. Even then, Columbia will remain just south of the jet as it rounds an upper-level ridge come Monday. The GFS attempted to resolve upper-level wind divergence above mid-Missouri come late Saturday evening. The NAM, on the other hand, showed no indication of divergence. Such disagreements continued to be found moving down in the atmosphere. 

A shortwave trough is expected to propagate through Central Iowa into Illinois after dark on Saturday. Along with this shortwave trough is a considerable pocket of vorticity with the most significant circulations to be expected in NW Illinois. The GFS appeared to have additional vorticity in parts of Central Missouri between 03Z and 06Z on Sunday, something that the NAM was not particularly keen on. That said, both deterministic models agreed on the shortwave and its associated vorticity over Illinois late Saturday and early Sunday.

Mid-level moisture is on the plentiful side as we head into Friday evening and will allow for cloud cover heading into Saturday morning. The afternoon should reveal a sky that is more blue than it is cloudy, but a few clouds may remain. A warmer day is anticipated due to WAA over the region. Moisture transport vectors modeled by the NAM indicated a greater magnitude of moisture being brought into the mid-levels come late Saturday evening. The GFS does not suggest that there will be any increase in mid-level moisture content--something that was peculiar considering the model was resolving precipitation over mid-Missouri. The NAM is currently pushing more moisture in from the Gulf of Mexico on Saturday evening, but a considerable lack of large-scale ascent over Central Missouri seems to be a factor inhibiting precipitation. Moreover, the low and near-surface levels remain quite dry Saturday into Sunday. Such a substantial dry layer will make it difficult for any rain to reach the surface as it will likely evaporate before making contact with the ground. The possibility of convection was also assessed, but was ultimately found to be minor. Sharp low-level temperature inversions combined with the lack of ascent and forcing mechanism will make convection quite difficult in Columbia this weekend. It is important to note, though, that such stark model disagreement has made the precipitation forecast rather difficult. Based on forecaster experience, it was decided that precipitation is unlikely with convection even more improbable. Activity will be primarily concentrated to our north along the MO-IA border and Illinois as that shortwave trough makes its mark. 

Temperatures were of lesser concern during the forecast process due to them having a much lesser uncertainty. The NAM and the GFS alike were incredibly hot with their Saturday and Sunday high temperatures, something that was rebuked by the NBM. The NBM has much less variation in the possible maximum temperatures for Saturday and Sunday, but, as expected, uncertainty grows heading into next week where there is the possibility of record-breaking heat for the Columbia area.

- Macko