Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 344 AM EDT Tue Jul 21 2020 Valid 12Z Tue Jul 21 2020 - 12Z Thu Jul 23 2020 ...Relief from the heat for portions of the Northeast Tuesday and Wednesday, hot and humid conditions continue across the remainder of the East and Northwest... ...Severe weather and flash flood threats from portions of the northern and central U.S. into the Ohio Valley and Mid-Atlantic into mid-week... ...The Gulf of Mexico will be monitored for potential tropical development this week... The stifling summer heat and humidity is taking a temporary break across the Northeast in wake of a passing cold front. High temperatures on Tuesday and Wednesday dip back into the 70s (northern New England) and 80s (southern New England/New York). Subtle relief will also be seen farther south into the Mid-Atlantic region where high temperatures become a few degrees cooler Tuesday and Wednesday than what was seen Sunday and Monday, but highs in the 90s will persist through mid-week along with uncomfortably humid conditions. Heat Advisories are in place from the Chesapeake Bay on south into the Carolinas today as heat indices over 105 degrees are expected. The cold front that passed through the Northeast is forecast to stall from the east-central U.S. into the Central Plains on Tuesday. This front and another frontal system moving through the north-central U.S. will spark showers and thunderstorms from the Heartland to the Mid-Atlantic today and into Wednesday. Tuesday's Slight risk area for severe weather resides in the central High Plains while several Slight risk areas for flash flooding are located in the Great Lakes, mid-Mississippi Valley, and the Mid-Atlantic. The threat for severe weather and flash flooding becomes focused in the northern Mid-Atlantic and Ohio Valley on Wednesday, Farther south, a tropical wave will send showers and thunderstorms near the Florida Keys into the Gulf of Mexico mid-week. This disturbance could generate heavy showers and thunderstorms along the central and western Gulf Coast the second half of the week. The National Hurricane Center is watching this tropical wave closely for potential development later this week. Across the western U.S., above average heat will continue in Washington/Oregon into the Intermountain West on Tuesday. For Wednesday, highs in the mid-upper 90s are expected to shift east into the northern Rockies and High Plains but a cold front provides cooler weather to the Pacific Northwest for Wednesday. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php