Heavy snow over parts of Central Rockies Wednesday night intoThursday.There is a Slight Risk of severe thunderstorms over the Plains andMississippi Valley from Wednesday to Thursday,There is a Slight Risk of excessive rainfall over parts of the SouthernPlains/Lower Mississippi Valley on Thursday.A front extending from the Northern High Plains to the Great Basin willmerge with a front extending from the Upper Great Lakes to the SouthernHigh Plains overnight Wednesday, moving to the Southern Plains andSouthwest by Thursday evening. The western boundary will produce coastalrain with embedded thunderstorms and snow over the Cascades throughWednesday morning. Snow will also develop over parts of the NorthernIntermountain Region, Great Basin, and Northern Rockies Through Wednesdaymorning. On Wednesday, an upper-level low will develop over the GreatBasin. The upper-level low will draw moisture northwestward from the Gulfof Mexico. Heavy snow will begin to develop over parts of the CentralRockies Wednesday afternoon into evening.Furthermore, the significant and long-duration winter storm will developacross the Central and Southern Rockies beginning Wednesday, followed by around of heavy snow for the Southern Rockies and Four Corners regionThursday night.Further, snow probabilities are high (greater than 70% chance) for atleast 1 foot for most of the Colorado Rockies, the Front Range Mountains,the Foothills, and the Palmer Divide. Localized higher amounts areexpected and could exceed 2 feet across the Front Range Mountains (30-50%chance). Confidence is also increasing for a significant snowfall for theI-25 corridor and snow probabilities for at least 8 inches are high(greater than 70% chance).A second phase of the winter storm will impact the Four Corners Regionbeginning Thursday night. Waves of heavy snow will impact the terrainareas north of the Mogollon Rim and northeast toward the San Juans andsouthern Colorado Rockies. Snow probabilities for 8 inches are moderate tohigh (greater than 50%). Localized totals above a foot are possible forthe higher terrain.Hazardous to very difficult travel is expected as heavy snow and intensesnow rates at times (1-2 inches plus per hour) will lead to deterioratingtravel conditions beginning Wednesday and Wednesday night across theCentral/Southern Rockies and beginning across the Four Corners regionThursday night.Moreover, on Wednesday evening, as the front begins to merge with theEastern Front, showers and severe thunderstorms will develop over parts ofthe Central Plains/Middle Mississippi Valley. Therefore, the SPC hasissued a Slight Risk (level 2/5) of severe thunderstorms over parts of theCentral Plains/Middle Mississippi Valley from Wednesday through Thursdaymorning. The hazards associated with these thunderstorms are frequentlightning, severe thunderstorm wind gusts, hail, and a few tornadoes.Additionally, there is an increased threat of hail two inches or greaterover parts of the area.Furthermore, overnight Wednesday, showers and thunderstorms will expandalong the front from the Central Plains/Middle Mississippi Valley into theOhio Valley/Great Lakes and extend into parts of the Southern Plains/LowerMississippi Valley.On Thursday, showers and severe thunderstorms will extend from the MiddleMississippi Valley to the Southern Plains/Lower Mississippi Valley.Therefore, the SPC has issued a Slight Risk (level 2/5) of severethunderstorms over parts of the Middle Mississippi Valley to the SouthernPlains/Lower Mississippi Valley on Thursday. The hazards associated withthese thunderstorms are frequent lightning, severe thunderstorm windgusts, hail, and a few torna