Merry Christmas December 25, 2024 .... With Ion Meteorologist Steve Pellettiere

It will be a tale of two weather patterns for the country heading throughthe Christmas holiday, as portions of the West and south-central U.S. seea couple rounds of unsettled weather while most other locations remaindry. In the West, moderate to heavy lower elevation rain will remainpossible with showers and thunderstorms in California though Christmas Eveas a Pacific system moves inland, with heavy higher elevation snow for theSierra. Some isolated flooding will remain possible along upslope regionsof the Sierra. The precipitation focus will spread inland over the GreatBasin and northern/central Rockies through Christmas Eve night and intoChristmas morning as the system continues eastward, with a mix of rain andsnow for lower elevations and snow into the mountains. Any accumulationsshould light for lower elevations with a few inches possible in themountains. Another Pacific system will approach the PacificNorthwest/northern California on Christmas day bringing another round ofmoderate to heavy lower elevation/coastal rain and heavy high elevationsnow. Some isolated flooding will be possible along upslope regions of thecoastal ranges, and Winter Storm Watches have been issued for the Cascadessouth through the Mt. Shasta region in California for snow totals of 1-2feet through Thursday. The system will continue inland into the dayThursday bringing more lower elevation rain/snow and high elevation snowto the Great Basin and northern/central Rocky Mountains. Heavy snow totalsof 4-8 inches, locally 12"+, are also expected through many ranges of thenorthern Great Basin/Rockies. Any accumulations at lower elevations shouldremain light. Strong, gusty winds will spread inland with the system andlead to blowing snow at higher elevations.To the east, showers and thunderstorms remain in the forecast for portionsof the south-central U.S. the next couple of days as a couple upper levelwaves/surface systems pass through the region. Showers and thunderstormswill continue through this evening over eastern Texas and into theArkLaTex ahead of the first system. Some severe thunderstorms producingmainly hail and isolated damaging winds are possible, as well as somelocally heavy downpours and isolated instances of flash flooding. Thissystem will make little progress eastward and weaken Christmas day as asupporting upper-level wave departs the region, which fortunately meansmore scattered chances of storms into the Middle/Lower Mississippi Valley.Then, by early Thursday, another upper-level wave dropping southward willlead to lee cyclogenesis and a second frontal system pushing eastward intothe southern Plains. Plentiful Gulf moisture lingering just along thecoast will quickly return back northward over Texas/Oklahoma and into theArklatex, leading to a renewed round of showers and thunderstorms. Severeweather will once again be possible with a Slight Risk (level 2/5) issuedfrom the Storm Prediction Center for the threat of damaging winds as wellas the potential for tornadoes. In addition, widespread storms producinglocally heavy downpours will also once again bring the threat of someisolated flash flooding. Some more scattered showers and storms will bepossible further northeastward into the Middle and Upper MississippiValleys as well.