Heavy rain/flooding and gusty winds will continue at least through thisevening in South Texas associated with Tropical Storm Alberto......Heavy rain and flash flooding concerns increase for the north-centralU.S. later Thursday into Friday......A heat wave will persist over the Great Lakes, Ohio Valley, and theNortheast into late week...Tropical Storm Alberto has formed in the far western Gulf of Mexico and isforecast to make landfall in Mexico around Thursday morning. Alberto willhave impacts extending into southern Texas north of its center ofcirculation, including tropical-storm-force winds and storm surgecontinuing through tonight and heavy rain/flooding concerns. These hazardsare likely to be enhanced by surface troughing near the Gulf Coast thatfocuses the ample tropical moisture. Rainfall amounts of 5 to 10 inchesare expected into South Texas, which could produce considerable flash andurban flooding along with new and renewed river flooding. Thus a ModerateRisk is in place in the Excessive Rainfall Outlook through tonight, with aSlight Risk in place for Thursday for South Texas. While Alberto shouldweaken rapidly over the higher terrain of Mexico on Thursday and reducewinds, the tropical moisture will stream north and trigger showers andthunderstorms across the southern High Plains and Four Corners region onThursday and Friday, where Marginal to Slight Risks of excessive rainfallare highlighted. Meanwhile over the western Atlantic, moisture associatedwith a tropical wave could reach northeastern Florida and coastal GeorgiaThursday night to Friday morning.Though the north-central U.S. is seeing a relative break in heavy rainfalltoday behind a cold front, renewed support for thunderstorms with heavyrain is likely there Thursday into Friday. Upper-level energy and thefront stalling and drifting north will reinvigorate storms in central tonorthern parts of the Plains and Mississippi Valley into the Midwest.Moderate Risks of excessive rainfall have been introduced for easternSouth Dakota into parts of Minnesota and western Wisconsin on Thursdayinto Friday, meaning numerous flash floods are likely. Antecedentconditions there are wet because of previous rainfall, so this contributesto flooding concerns. Farther east, scattered thunderstorms are likelyacross the Great Lakes region and Northeast. Marginal to Slight Risks aredelineated each day from the Storm Prediction Center (mainly for thethreat of severe wind but with some low chances for hail), and MarginalRisks of excessive rainfall are in place as well.All these rain and thunderstorm areas are taking place along the peripheryof an upper ridge/heat dome that edges from the Mid-Atlantic into theMid-South over the next couple of days, producing a record-breaking heatwave across the Great Lakes, Northeast, and Mid-Atlantic. Afternoon hightemperatures and warm overnight lows will challenge daily records and evensome monthly and all-time records. Heat index readings are expected topeak from 100 to 105 degrees in many locations. Those without access toreliable air conditioning are urged to find a way to cool down. Recordwarm overnight temperatures will prevent natural cooling and allow theheat danger to build over time indoors without air conditioning.Temperatures may be lower and less hazardous closer to the coast if/wheresea breezes form. By Friday, conditions should improve over New Englandbehind a cold front, but temperatures well into the 90s and higher heatindices are forecast to continue across the Ohio Valley to Mid-Atlantic.Meanwhile, cooler than average highs are likely into the southern HighPlains with the clouds and rain forecast, but temperatures over the Westwill gradua