Issued: 11am on Monday, October 11th 2021
Technical Forecast Discussion
Short Term (Monday 10-11-2021 through Wednesday 10-13-2021)
Our forecast period starts out with strong upper-level low over east-central Kansas area as of this morning which on surface is translating to mature surface low pressure area on the right-entrance region of Jet stream over far southeastern Kansas. Further to the east, we are under the axis of upper level ridge from central gulf coast states and up to much of eastern half of Ohio Valley into Northeastern area. Our area is experiencing southerly flow, leading to surge of warm air and high humidity to filter into our area on Monday as the surface high pressure continues to move eastward. As we continue to progress through the day on Monday, the upper-level low will start to weaken rapidly as it pushes into northern Illinois area, this would also lead the surface low to weaken rapidly, due to occlusion, as it pushes northward into Great Lakes area by Tuesday. The trailing cold front will be pushing eastward into into our area by late Tuesday. The front itself either barely pushes through our area and falls apart or could fall apart before passing us, this solely matters in terms of actual surface temperatures being 2°-3°F cooler (in middle 70’s) vs being warmer (upper 70’s-low 80’s) during afternoon hours. Overall, no precipitation is expected from this and will only result in partly cloudy skies. While this upper-low weaken, it also contributes to a break in the upper ridge in our area for early part of Tuesday. As we head later in Tuesday, new axis of upper level ridge develops in our area and intensifies through out the day on Wednesday. On surface level, another warm front will lifting north of our area on Wednesday, but given that we will far away from surface low over northern plains, lack of forcing would result in no precipitation for us. Temperatures during this period will start on warm note with highs in mid 80’s on Monday, but cooling into upper 70’s for Tuesday and Wednesday. Morning lows will be in low 60’s Monday night, cooling into lower 50’s Tuesday night, and warming up once again by Wednesday night to upper 50’s. Overall temperature departures will be in 10°F-15°F above normal range for this time of the year.
Long Term (Thursday 10-14-2021 through Sunday 10-17-2021)
Long term range resumes with an axis of upper level ridge overhead which then gradually starts to weaken as we progress into the day on Thursday into first half of Friday. The reason for weakening of this ridge is attributed to a strong short-wave within broad trough axis over western half of United States barreling northeastward into Manitoba and western Ontario and push on the upper level ridge to the east. On surface level, we will continue to remain under southerly flow on Thursday into early Friday, which allows humidity and warm air to flood in once again out ahead of surface cold front to our west. While the short-wave weakens out, the main trough axis will slowly push eastward and eventually move in our area properly by Saturday. Given our weather pattern is progressive, the trough will continue to move eastward through Saturday and we will be on far eastern end of the trough by late Sunday. Looking at surface, cold front eventually clears our area by late Friday and much cooler weather moves into our area by Saturday and Sunday and true fall weather return in our area. While these cooler weather feel like a “shock” but our temperatures actually only return to normal levels for this time of the year and we might still be only couple degrees above normal by Sunday. Overall temperatures during this period will start out into low-mid 80’s for highs on Thursday which drops into upper 70’s on Friday with mid-upper 60’s by Saturday and Sunday for our highs. Morning lows will cool from upper 50’s-low 60’s Thursday and Friday night to low-mid 40’s by Saturday and Sunday night. Overall temperature departures during this period will still remain about 6°F-12°F above normal, but fortunately fall weather returns by this weekend.