Issued: 12am on Thursday, January 1st 1970
Technical Forecast Discussion
Short Term (Wednesday 7/10 through Saturday 7/13)
The awaited system from the upper Great Plains has propagated further east and is nearing the northern Great Lakes region as of 02z Wednesday. This is an upper-level shortwave trough that has a well associated surface low as well as defined frontal boundaries. This troughing currently has a relatively strong jet in the Midwest that extends southwest to northeast with values up to 100 knots. As the disturbance begins to affect us early Thursday morning with its right entrance region, the upper level values begin to weaken with the stronger values near the low itself. This is to attribute to the timing and the diurnally driven effects. As it shifts further northeast, these upper-level winds will instead be an issue for the northeastern states as they take up this upstream location. Southerly flow continues to ramp up for the area in advecting warm temperatures and more low-level moisture with dewpoints into the low-mid 70s. Nonetheless, this will bring the first wave of rain showers early on Thursday before the cold front from the northwest bringing in thunderstorms. A careful watch on Thursday’s afternoon storms ahead of the boundary as they may turn severe with our current Day 2 Slight risk form the SPC. This generated unstable environment will have CAPE increase upwards to 3500 J/kg, but weak-moderate speed and directional shear, in turn will influence a likely multi-cell environment. Strong gusty winds look to be the primary severe threat, but the risk for severe hail to develop within some of the storms is possible. Showers and storms should wrap up heading into Thursday night as the cold front drops in some CAA and northwesterly flow. This introduces dry conditions with the dominating high pressure and will offer a brief relief to the humidity for Friday and first part of Saturday. Temperatures for the period maintain into the mid-upper 80s, but again look to be slightly warmer with highs reaching near 90 for late weekend and early next week. Cloud cover should also decrease for this forecast period before the next unsettled pattern on Sunday and further out.
Long Term (Sunday 7/14 through Tuesday 7/16)
Another upper-level shortwave is projected to swing across the Great Lakes that is to clip southeastern Ohio and bring in more chances for showers and thunderstorms for Sunday afternoon/evening. The chances for showers may continue to exist as a stationary front looks to lift to the northeast on Monday. Confidence is low for the period heading into early next week with the ongoing disturbance (Invest 91) in the Gulf of Mexico. The models are not currently agreeing with each other on the further progression inland. High pressure looks to form for southwestern and southeastern U.S in potential aid for impacts to our region. The GFS currently has the system moving north along the Mississippi river valley that may bring in more tropical moisture and the risk for rain for the end of the period; this pattern looks to subjected to change with newer model runs.