Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 326 AM EDT Sun May 18 2025 Valid 12Z Sun May 18 2025 - 12Z Tue May 20 2025 ...Multiday severe weather and flash flooding threat to begin across the central United States today... ...Summerlike and potentially dangerous heat continues across parts of South Texas and Florida... ...Critical fire weather conditions forecast across much of southern New Mexico and West Texas... A busy mid-May weather pattern is expected to take shape over the next few days and bring a multitude of hazardous weather to the Lower 48, including heavy rainfall, severe thunderstorms, fire weather, and even heavy mountain snowfall. The storm system responsible for the upcoming active weather is currently traversing the Intermountain West and spreading widespread showers and mountain snow to the region, highlighted by Winter Storm Warnings over parts of Idaho and western Montana for up to a foot of snowfall today. As this system continues to slide eastward while strengthening, the precipitation shield will expand throughout the northern/central Rockies before numerous showers and thunderstorms develop across the central/southern Plains by this evening. All modes of severe thunderstorms are possible through tonight across a region spanning from northeast Colorado and southwest Nebraska into much of the central Plains and as far south as the Concho Valley of Texas. Thunderstorms may contain large hail and damaging winds, with the greatest threat of tornadoes located from central Kansas to central Oklahoma, where the Storm Prediction Center has issued an Enhanced Risk (level 3/5) for severe weather. Additionally, numerous thunderstorm complexes developing along both a slowly lifting warm from extending from the central Plains to the Mid-South, as well as dry line located in the southern High Plains will have the potential to produce intense rainfall rates capable of leading to instances of flash flooding. As a result, A Slight Risk (level 2/4) of Excessive Rainfall has been issued from eastern Kansas and Oklahoma into the Ozarks of Missouri and Arkansas through early Monday. Day 2 of this spring storm system is anticipated to spark another round of widespread strong storms on Monday as as area of low pressure churns over the central United States and primary atmospheric ingredients reload. Heavy rainfall is once again expected to blossom throughout the southern Plains and Lower Mississippi Valley, while also expanding northward into South Dakota. Locally intense rainfall rates are possible from North Texas into Arkansas, as well as northern Missouri into southern Iowa. Where the heaviest rainfall does set up and linger for multiple hours, flash flooding is possible and could become significant should it align over sensitive terrain and/or urban locations. Thunderstorms are also expected to once again produce areas of damaging winds and large hail on Monday throughout a large part of the central/southern Plains and Ozarks, with the threat of tornadoes also continuing in this region. By Tuesday, this potent May storm system begins to slide east and shift the dangerous thunderstorm threat into the Midwest, Tennessee and Ohio valleys. Scattered instances of flash flooding and the potential for severe thunderstorms will remain although shifted east compared to the prior two days. With widespread severe weather and heavy rainfall forecast it is paramount to stay weather aware, have multiple ways of receiving warnings, have a plan should severe storms strike, and remain in communication with family/friends. For up-to-date local forecasts find your local weather forecast office at www.weather.gov. The temperature outlook through early this week continues the theme of early summer across the Gulf Coast States, with an emphasis on South Texas and the Florida Peninsula. Here, highs will once again rise into the mid-to-upper 90s (triple digits in south-central Texas), which could potentially break daily records along with creating a potentially situation for those without adequate air conditioning. Elsewhere, below average temperatures will be found in the Rockies and Northern Tier. Frost Advisories are widespread this morning throughout the Dakotas and Minnesota where low temperatures are forecast to dip into the 30s. Meanwhile, a warming trend is expected to develop across California early this week as highs begin to enter the 90s in the typically hotter valley locations. Critical fire weather conditions are also notable through early this week across the southern Rockies and into portions of the southern High Plains. Very low relative humidity, dry vegetation, and gusty winds are forecast which could lead to the rapid spread of wildfires. Red Flag Warnings have been issued. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php