Issued: 11pm on Tuesday, September 14th 2021
Technical Forecast Discussion
Short Term (Tuesday 9-14-2021 through Thursday 9-16-2021)
Period starts out with a broad trough on Tuesday over most of Mid-West region which quickly translates eastward into our area by Tuesday night into late Wednesday afternoon before it starts to fall apart with 500mb heights rising again. This trough will generate a surface cold front which will push into northwest Ohio initially on Tuesday night which then moves through the state and clear us by Wednesday evening. Given that there will be plenty of heat and humidity along with strong belt of 30-40kt winds aloft in lower to middle part of atmosphere will lead to marginal severe weather risk for our area on Wednesday. It is important to keep in mind that this front will moving rather at slower pace and heavy rainfall from thunderstorms are possible which may lead to isolated flooding instances given our grounds are still saturated. Drying trends are expected for Thursday as the trough dissipates and higher 500mb level heights start to develop overhead, this will lead to temperatures still remaining on warm side along with elevated humidity levels despite passage of cold front. Temperatures will be warm in upper 80’s on Tuesday under dry conditions with only upper 70’s to low 80’s expected for Wednesday and Thursday with lows remaining in low-mid 60’s.
Long Term (Friday 9-17-2021 through Monday 9-20-2021)
Long term period on Friday starts off with continued intensification of 500H ridge with 588dm values popping over our area with main ridge axis over southwest Atlantic ocean. This upper level flow pattern will promote generic southwest flow in our area which will allow heat and humidity to persist in the area during this entire period. By Saturday, the main ridge axis over southwest Atlantic weakens off, but we have another ridge axis area develops over central and northern plains. This ridge axis is then expected to shift directly overhead by Sunday as 591dm ridge pops off right over Ohio Valley and becomes centered right over us. The ridge area on Monday will continue to remain over our area and continue to expand to most locations in Mid-Atlantic and Northeast region. Looking at precipitation risk during long term period, Friday appears to be dry with very isolated pop-up storm risk on Saturday as we would be under return southerly flow of high pressure. Risk of rainfall should go down on Sunday as we will have surface high being near central West Virginia area, but diurnal thunderstorm chances increase as we head into Monday as surface high moves eastward into Pennsylvania and Maryland area. Our overall temperature departures during this period will run about 9°F-14°F above normal and it is important to note that our average temperatures during mid September are mid 70’s for high with lows in lower 50’s. This would mean that I expect high temperatures to return into mid-upper 80’s with lows only dropping in middle 60’s with peak afternoon heat index in upper 80’s to low 90’s due to higher humidity levels for Friday through next Monday.
