Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
Versions:
1
968 FXUS01 KWBC 221907 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 306 PM EDT Wed Jul 22 2026 Valid 00Z Thu Jul 23 2026 - 00Z Sat Jul 25 2026 ...Impactful flash flooding expected across portions of the southern Mid-Atlantic/Carolinas west through the Tennessee Valley through Friday... ...Tropical Storm Bertha is expected to generate isolated flash flooding, tropical storm conditions, and coastal flooding along the Gulf Coast and into southern Texas... ...Monsoonal thunderstorms continue over much of the Intermountain West and adjacent High Plains... ...Hazardous heat continues over parts of the Southern Tier; builds over the Great Basin and Northern Plains Friday... The National Hurricane Center continues to track Tropical Storm Bertha, currently located near the southeastern Louisiana coastline as of mid-day today (Wednesday), and forecast to move westward along the northern Gulf Coast through Thursday and into southern Texas by Friday. Tropical storm conditions are expected to continue along the northern Gulf Coast from the western Florida Panhandle to southeastern Louisiana, including the metro New Orleans area, through tonight. Tropical storm conditions are possible for portions of the southeastern coast of Louisiana and upper Texas Gulf Coast through late Thursday. Isolated areas of flash flooding remain possible through Friday morning along the northern Gulf Coast and into southern Texas with coastal flooding possible as well. Meanwhile, an impactful flash flood threat will continue across portions of the southern Mid-Atlantic/Carolinas into Tennessee Valley the next few days as moisture associated with Bertha helps to augment an already anomalously moist airmass over the Southeast. The moisture pooling along a quasi-stationary frontal boundary will support widespread, very heavy rainfall producing storms. A Moderate Risk of Excessive rainfall (level 3/4) is in effect for southeastern Virginia and into extreme northeastern North Carolina today where training/repeated rounds of storms will bring a scattered to widespread and potentially significant threat of flash flooding. This threat will shift a bit southward further into northeastern North Carolina tomorrow as the front slowly pushes southward, with another Moderate Risk in effect. A Slight Risk (level 2/4) extends westward through portions of the southern Mid-Atlantic/Carolinas and into the southern Appalachians through tonight, with Slight Risk areas through the Carolinas and into the Tennessee Valley on Thursday and Friday for additional scattered instances of flash flooding. Monsoonal moisture will bring the threat for scattered flash flooding across a broad swath of the Great Basin/Southwest/Four Corners region and into portions of the Rockies this afternoon, with a Slight Risk of Excessive Rainfall in effect. The threat will shift a bit further east on Thursday with a Slight Risk for portions of eastern Colorado while a Marginal Risk (level 1/4) continues from the Southwest/Four Corners region into the central Rockies for more isolated instances of flash flooding. Further east, northwesterly flow will promote widespread, organized thunderstorm complex development both tonight as well as on Thursday. A Slight Risk of Excessive Rainfall is in effect Thursday over portions of the central Plains/Missouri Valley as this second round of heavy rainfall on already saturated soils may lead to scattered flash flooding. Hazardous heat continues this week over the Southern Tier of the U.S. before beginning to expand northward through the Great Basin as well as across the Northern and then Central Plains Friday into the weekend. Forecast highs range in the mid-90s to mid-100s with heat indices exceeding 105-115 degrees for some locations. Record warm overnight lows in the 75 to 80 degree range will provide little relief from th heat overnight. Widespread major to locally extreme HeatRisk (levels 3 and 4/4) is expected which indicates a level of heat dangerous to anyone without adequate cooling or hydration. Continue to monitor WPC`s Key Messages for more details and updates on the heat. One last day of hot, record-tying/breaking temperatures continues today for the Pacific Northwest before a cold front brings relief Thursday. Temperatures will be below to well below average and mild for mid-Summer across much of the Midwest to Mid-Atlantic/Northeast following a cold front passage, with highs in the 70s to low 80s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$