Issued: 9:00pm on Wednesday, July 11th
Technical Forecast Discussion
Short term (Wednesday 7/11 through Saturday 7/14)
High pressure will settle over Michigan this evening. Moisture will be slim as an upper level trough leaves the region. Small CAA will still exist this evening from the cold front that affected us yesterday. Lows should be no higher than 60 degrees. As skies become clearer tonight, some late night fog looks to be possible. On Thursday, an upper level ridge moves into the area that will begin to bring slight WAA from west that will not be too noticeable as northern flow will continue to bring cooler air until Friday. High pressure moves into Ohio which pushes a pocket of exceptionally dry air will pass over the area on Thursday afternoon which will block any moisture developing and will serve to keep skies clear. Temperatures will be in the mid to upper 80s. On Friday, the ridge is centered over the region which will push a band of moisture into the state. Humidity will begin to rise in the later afternoon, lining up with peak heating hours. Temperatures will be in the high 80s with the heat index possibly in the low 90s. High pressure will be over the area on Friday as well indicating a continuation of clear skies and calm weather. On Saturday, shallow troughing forms in the upper atmosphere. The trough appears to lack strength at the mid levels, so the amount of influence it will have on weather patterns will vary depending models and mesoscale level activity. Currently, only the NAM shows any significant CAPE values, which are around 1750 J/kg. Moisture will be available, but a weakening cold front will be the only reliable forcing mechanism. Diurnal heating could also spur precipitation on Saturday as temperatures will be in the low 90s with humidity around 50 percent. Humidity could also bring on a heat advisory as the heat index could enter the high 90s.
Long term (Sunday 7/15 through Tuesday 7/17)
Narrow upper level ridging occurs on Sunday that will trap moisture from the previous day in the region as more moisture continues to arrive. Temperatures remain in the low to mid 90s on Sunday, but with humidity around 60 to 70 percent, heat indexes could peak in the low to mid 100s. Similar CAPE values to Saturday will exist and moisture amount will be greater, so pop up storms and showers will have a greater chance of occurrence on Sunday. Sunday night will be humid and will allow for storms to occur overnight. On Monday, an upper level trough approaches that will push a cold front through the Midwest. Conditions for storms look more favorable north of the region, but chances for storms and showers will uncertain and scattered in nature as CAPE values remain low and high pressure will be just South of the area. On Tuesday, the cold frontal boundary will be over Northeast Ohio. CAPE values remain low, but vorticity created by frontal dynamics will help produce convection through interaction with moisture and forcing through diurnal heating. Storms look to be long tracked, so flood risk can not be ruled out.
The next technical discussion will be Sunday 7/15