North Carolina State University
Cucurbit Downy Mildew Forecast

Weather - Central & Eastern U.S. / southern Canada: Wet weather in the Southeast with Tropical Storm Fay; showers and thunderstorms from TX / southern MS Valley northward into the Midwest; Dry weather elsewhere. Tropical Storm Fay crossed central FL yesterday and today. Now near Daytona Beach, heavy rain is expected across the lower Southeast as Fay tracks to the WNW over the next several days. A few showers to the north of the storm are expected also. Rainy weather is also expected from the south-central U.S. northward into the Midwest, fueled by moisture from the Gulf and a lingering upper-level disturbance. The other main weather feature is an abnormally strong high pressure area centered over the lower Great Lakes. The center will drift east with time, but the High will govern the weather over the remainder of the central and eastern U.S. and southern Canada for the next several days; sunny to partly cloudy skies and little to no rainfall. Temperatures quite cool for August under the High to the north, and under the clouds and rain in the south.

OUTLOOK

Wednesday and Thursday - Highest risks in the southern U.S.; Low Risks elsewhere.

Wednesday and Thursday: Conditions for survivable transport and deposition will be favorable across the southern U.S. Wednesday and Thursday. Transport to other regions is not expected. Events in the Southeast will be wrapped up in Fay, or travel under unfavorable conditions. Events from TX and LA move north, but rainy weather in that region should wash out airborne spores near the source areas. Elsewhere, many events move toward areas not now affected. However, solar exposure will kill airborne spores during transport, and there is little to no chance of rain during the events. HIGH RISK for cucurbits in southern GA, northern FL, southern SC, southeast TX, central and southern LA, and southwest MS both days. Low Risk otherwise.

Forecast details for the known sources are provided below.

TK

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Current Sources:

• Southern GA / northern FL
• Charleston, SC
• Eastern NC / southeast VA
• DelMarVa peninsula / NJ / southeast PA
• Southeast TX
• Western and southeast LA
• Western and central MI
• Southern Ontario / southeast MI / northern and central OH, northwest PA
• Western NY / southern Quebec
• Canton and Woodleaf, NC; York County, SC
• Southwest and central PA
• Fortville, IN
• East Windsor, CT