Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 347 AM EDT Thu Jul 30 2020 Valid 12Z Thu Jul 30 2020 - 12Z Sat Aug 01 2020 ...Areas of heavy rainfall and some flash flooding are expected through the end of the week from the Central Plains and Middle Mississippi Valley east to the Mid-Atlantic region... ...Extreme heat, dry weather and locally elevated fire danger will be the story across the West... ...Tropical Storm Isaias will impact Puerto Rico and Hispaniola today and may approach South Florida by early this weekend... Heavy showers and thunderstorms will be impacting portions of the central Plains and middle Mississippi Valley today as multiple waves of low pressure advance east along a frontal boundary draped across the region. This wet weather will advance east into areas of the Ohio and Tennessee Valleys, and the Mid-Atlantic region by Friday as the same front and surface low activity gradually shifts off to the east and south. Some areas of flash flooding will be possible, and there will also be at least a localized threat of severe weather. The widespread cloud cover and threat of rain will generally foster below normal temperatures through the remainder of the week across especially areas of the central Plains, mid Mississippi Valley and lower Ohio Valley where daytime highs may be as much as 10 to 15 degrees below normal. Meanwhile, extreme heat and locally elevated fire danger will be the story across much of the Pacific Northwest, Great Basin and the Southwest U.S. as a strong ridge of high pressure develops over these areas. Record high temperatures are expected in some cases as temperatures approach and exceed the triple digit mark for many of the interior deserts. In fact, areas of the Desert Southwest are likely to see temperatures reach into the 110 to 120 degree range. The abnormally hot weather in conjunction with very dry air and locally gusty winds will enhance the fire danger as a result, with the biggest concerns across the Northwest given the potential for lightning strikes associated with some dry thunderstorm activity. All eyes remain fixed as well on newly formed Tropical Storm Isaias (pronounced ees-ah-EE-ahs) which is currently south of Puerto Rico and moving to the northwest. The storm is expected to impact Puerto Rico and Hispaniola today, before then advancing close to the Bahamas on Friday. By this weekend, the storm may begin to approach South Florida. Heavy showers and thunderstorms, along with strong gusty winds are expected in association with Isaias. Please consult the latest National Hurricane Center public advisories for more information. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php