Issued: 7pm on Tuesday, October 5th 2021
Technical Forecast Discussion
Short Term (Tuesday 10-5-2021 through Thursday 10-7-2021)
Rather interesting weather pattern has settled in to start out our short term period given the fact that an upper level low is blocked out and stuck over Arkansas/Mississippi due to anomalous upper level ridge which has moved over upper Great Lakes region as of today. This pattern on surface is translating to surface low over northeastern Mississippi, which has resulted in heavy downpours in the south, while our area had dry weather to deal with given surface high over UP Michigan. As we progress in Wednesday into Thursday, 500H ridge axis will continue to move eastward and weaken out a little, and this will allow ULL to finally move northward into central Missouri/Illinois area and weaken out by that period. There is a surface warm front which will also push northward into our area by afternoon hours on Wednesday which then allows for deeper moisture profiles to return in our area. Given the diurnal effects along with weak mid-level energy rotating through our area, we will likely see best chances of pop-up showers and storms during afternoon/evening hours of Wednesday and Thursday. Chance of precipitation won’t be non-zero during overnight hours given the forcing from ULL keeping the chances in place for our area. Overall, we will note temperatures during this period remaining in upper 70’s to lower 80’s for highs with morning lows in lower 60’s. Typically, temperatures range from low 70’s for highs with lows in mid 40’s which means that highs are running about 8°F-12°F above normal while low temperature departures are even higher at 17°F-20°F with overall positive departure of 12°F-16°F.
Long Term (Friday 10-8-2021 through Monday 10-11-2021)
Long term period will feature continuous weakening of ULL and it finally merging into the Jet Stream as this upper low is currently cut off from main jet. We might still some residual precipitation risk on Friday for us, but the chances will be much lower as notable atmospheric forcing will be absent. Upper level heights will start to recover and rise in our area on Friday as another ridge axis appears to form over central and southern plains region which is then expected to move into our area by Saturday. As we move into Sunday, the 500H ridge should become even more established over our area as many models indicate 588dm strength. With the ridge building over our area, we should observe dry weather in our area for Saturday and Sunday. As we head into Monday, the upper level ridge will head eastward, as new short-wave is expected to move into central plains region. Another surface storm will develop in far western Ohio Valley region in response to the ULL and this may allow some clouds to work into our area on Monday while the day is looking to be dry so far. Our area will continue to remain under southerly flow throughout the long term period so our temperatures will continue to remain in upper 70’s to low 80’s for highs will lows mainly in mid-upper 50’s under slightly humid conditions so we will continue to note overall positive temperature departure of 12°F-16°F and keeping true fall like weather away from our area.
