Issued: 11pm on Friday, September 3rd 2021
Technical Forecast Discussion
Short Term (Friday 9-3-2021 through Sunday 9-5-2021)
Period is starting out with an 500H ridge over Arkansas and intensifying area of 500H trough over northern Rockies as of Friday evening. General northwest flow has kept cool and less humid conditions in the place for the region as surface high pressure dominates over central West Virginia through Saturday morning. As we progress forward in time, area of ridge will break down as the the trough moves and expands eastward into central and northern parts of Midwest and Great Lakes area through Saturday. As energy pivots to the base of the trough in Chicago area, surface low forms and lifts northward into southern Canada, and drag cold front through our area as result by Sunday afternoon. Best chances of seeing rainfall will be from Saturday evening through early afternoon hours of Sunday with 0.25″- 0.50″ appearing likely. Surface high pressure is then expected to settle in by Sunday evening along with continued CAA over the region as 500mb heights lower over the area. This weather pattern will result in highs mainly being in upper 70’s with lows in low-mid 50’s with exception to lower 60’s on Sunday morning.
Long Term (Monday 9-6-2021 through Thursday 9-9-2021)
Long term period continues with presence of 500H trough overhead by early Monday morning. As the day continues, the trough will shift eastward into Northeast region with height starting to recover once again locally. At the same time, another area of trough is expected to develop over southern Manitoba and Alberta which then is expected to quickly intensity and expand southeastward into northern Midwest and western Ohio Valley region. It is also important to keep a note that we will also have a shortwave imbedded with this trough which will propagate eastward. Weather conditions are largely expected to remain dry with temperatures warming into low to middle 80’s for highs with lows in mid-upper 50’s during nights under continued low humidity. This shortwave will likely lead to formation of surface low pressure to its southeastern side in U.P. Michigan by Tuesday afternoon and lift northeastward into southeastern Ontario and southwestern Québec by Wednesday into Thursday. At this same time, this low pressure area will drag another cold front through our region by Wednesday evening, but rain chances do not appear likely from this distance due to front weakening as it moves closer to our area. Weather conditions are expected to clear out once again with cooler weather regime enforced on Thursday with highs in lower-mid 70’s with lower 50’s for lows.
