Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 413 PM EDT Mon Jul 12 2021 Valid 00Z Tue Jul 13 2021 - 00Z Thu Jul 15 2021 ...Heavy rain and potential flooding for parts of the Eastern U.S. and the Desert Southwest... ...Heat wave continues for much of the western U.S. through early this week... ...Heavy rain and severe weather threat for the Plains and Midwest midweek... Unsettled weather continues in the Northeast U.S. as a slow moving warm front advances northward along with a very moist airmass, with dewpoints in the low to mid-70s. Widespread moderate to heavy rainfall with embedded thunderstorms are forecast through the period. Of greatest concern is a Moderate Risk for Excessive rainfall for the New York City area through tomorrow morning. Rainfall of 2 inches and higher is forecast for heavily urbanized areas that have recently seen significant rainfall leading to saturated soils. A broader Slight Risk for excessive rainfall is in effect for portions of eastern Pennsylvania and southern New York where 1 to 2 inches of additional rainfall is possible through tomorrow. A Slight Risk is also in effect for portions of Upstate New York east of Lake Ontario for tomorrow with 2 inches and potentially higher rain totals forecast. The heavy rain may lead to flooding and rises on area rivers as the region has seen above normal rainfall recently. Some additional heavy rainfall is expected further south along a trailing cold front moving east across the Midwest and South, but the threat will decrease with time as the front weakens tomorrow. The intense heat wave that has been setting records across the western U.S. has peaked for most areas, with a gradual return to more seasonal temperatures expected as the upper-level ridge that has been in place continues to weaken. However, Excessive Heat Warnings remain in effect for most areas through Tuesday evening. Forecast highs on Tuesday include the mid- to upper 100s for the Desert Southwest and San Joaquin Valley in central California, low 100s for the Great Basin, and upper 90s to low 100s for the interior Pacific Northwest. Cooler high temperatures are forecast for central California and the Great Basin on Wednesday, with upper 90s expected in most areas. However, highs will remain relatively hotter in the interior Pacific Northwest with upper 90s to low 100s once again possible. Some relief from the extreme heat will also arrive in the form of monsoonal showers and storms each day across portions of Arizona and New Mexico. Slight Risks for excessive rainfall are in effect through Thursday morning. Heavy rain of 1-2 inches can be expected daily across the area, with higher amounts of 3-4 inches locally where the greatest downpours occur. The flood threat is highest for more urbanized areas and burn scars. As the storm system in the east moves north into Canada, a series of fronts will move through the Northern and Central Plains and into the Midwest. Showers and thunderstorms are expected to develop on Tuesday from the Northern High Plains east through the Upper Missouri Valley. A Marginal Risk for excessive rainfall is in effect with heavy rain of 1 to 2 inches possible. More organized storms are expected on Wednesday, and there is a Slight Risk for excessive rainfall in effect. Heavy rainfall of 1 to 3 inches with locally higher amounts of up to 5 inches is forecast. Severe weather is also a threat, and the Storm Prediction Center has issued a Slight Risk for portions of the Upper Missouri and Mississippi Valleys. The organized line of thunderstorms may produce high winds and short-lived tornadoes. Putnam/Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php