Current Conditions at Sanborn Field
Tuesday: Sunny. Becoming overcast by late afternoon. High: 60
Tuesday Night: Overcast. Low: 51
Wednesday: Isolated showers in the afternoon. High: 57
Wednesday Night: Rain. Low: 47
Thursday: Rain. High: 50
Discussion: Do October showers bring November flowers? Maybe not, but that doesn't change our chances of rain over the next couple of days. Rainfall is expected to be light and isolated during the day on Wednesday before more widespread precipitation begins Wednesday night into Thursday. Total rainfall accumulations are expected to be just under 1.25".
- Macko
====================================================================Forecasters: Macko
Date Issued: 10/26/21 10:00AM CST
Technical discussion:
This forecast was developed using GFS instruction. The NAM and the GFS modeled the high-pressure system affecting Missouri quite well. However, the NAM was several degrees below the Tuesday morning low temperature whereas the GFS modeled it with great accuracy.
Winds at 250-mb are negligible before the jetstream enters mid-Missouri on Wednesday with winds of 90 knots. This region of the jetstream will quickly push eastward as a more zonal flow is achieved, leaving central Missouri without jetstream influence on Thursday.
At 500-mb, positive vorticity begins to hug the Missouri-Kansas border during the day on Wednesday before reaching the central portion of the state later that night. This spin is expected to remain over the region throughout the day on Thursday. Its presence will likely influence precipitation and cloud cover experienced throughout this time period.
The 700-mb level is expected to remain mostly dry throughout the daylight hours on Tuesday, although a gradual build in moisture is anticipated. By Tuesday night, significantly more moisture will be present with relative humidity values around 95%. This condition will extend through the end of this forecast period. Vertical velocity becomes prevalent early Wednesday morning and is expected to persist throughout the day. That said, negative omega values vary in magnitude during the day on Wednesday. Vertical velocity is expected to peak in magnitude in the overnight hours on Wednesday.
Following the passage of the warm front, the 850-mb layer will also become moist on Wednesday. 95% relative humidity is expected in central Missouri later Wednesday night and into Thursday. Due to this, and in combination with the variables mentioned above, the greatest precipitation amounts will likely occur overnight on Wednesday into Thursday.
By early Wednesday morning, PWAT values will be at or above 1 inch. These PWAT values are expected to maintain their significance throughout the end of the forecast period. To further evaluate moisture depth, a GFS sounding was examined for the overnight hours on Wednesday. The dewpoint and temperature curves remain closely bonded all the way up to 300-mb.
- Macko
No comments:
Post a Comment