Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 341 PM EDT Thu Oct 17 2024 Valid 00Z Fri Oct 18 2024 - 00Z Sun Oct 20 2024 ...Powerful Pacific storm to bring much colder temperatures and widespread mountain snow throughout the Intermountain West and Rockies over the next few days... ...Heavy rain and scattered flash flooding possible for portions of the central/southern High Plains on Saturday... ...Cooler temperatures continue to bring areas of Frost/Freeze potential over the eastern half of the country Friday morning... ...Above average temperatures and gusty winds forecast across the central and northern Plains today, expanding across the northern tier of the country into the weekend... A powerful Pacific storm system continues to make its way through the Intermountain West today bringing showers and thunderstorms, heavy mountain snow, gusty winds, and much cooler temperatures. Heavy snowfall totals of 4-8", locally 12"+, are expected over the next couple of days for higher elevations of areal mountain ranges in the northern Rockies south through the Great Basin and into the Four Corners region. Strong, gusty winds on the order of 30-40 mph, locally 50 mph, can also be expected particularly along a cold front dropping southward through southern California and into portions of the Southwest. Temperatures are well below average, especially across the Great Basin and into the Southwest. Forecast highs on Friday are mainly in the 40s and 50s across the Intermountain West, with 60s to low 80s for Desert locations in the Southwest. Morning lows will drop into the 20s and 30s for much of the region outside of the Desert Southwest, especially across the Great Basin and into lower elevations of the northern Rockies. Many valley locations are covered with either Freeze or Hard Freeze Warnings as these frigid temperatures could kill/damage crops and may freeze external pipes. Further east, deep southerly flow on the east of the system will bring very anomalous moisture northward over portions of the central and southern High Plains, leading to widespread storms producing efficient heavy rainfall on Saturday. A Slight Risk of Excessive Rainfall (level 2/4) is in effect as totals of 2-4"+ could lead to some flash flooding despite dry antecedent conditions. Elsewhere, another system approaching the Pacific Northwest on Friday will begin to bring moist, Pacific flow inland along upslope portions of the Olympics and northern Cascades, leading to periods of heavier rainfall that may lead to some isolated flooding concerns. Temperature-wise, highs remain below average across much of the eastern U.S. in the wake of a strong cold front passage earlier this week, only rising into the 50s to the north and 60s to the south. Morning lows on Friday will once again drop into the 30s across the interior Northeast south through the Appalachians/Ohio Valley and even as far south as the Tennessee Valley. Frost Advisories are in place across much of the region, with some Freeze Warnings into the central Appalachians and Upper Ohio Valley. Conditions have moderated to the northwest over the Plains as southerly flow increases ahead of the Pacific system. This has resulted in widespread much above average temperatures into the 70s and low 80s, especially for the northern Plains into the Upper Midwest, accompanied by some gusty winds. Widespread Red Flag Warnings as well as a Critical Risk of Fire Weather from the Storm Prediction Center (level 2/3) remain in effect Thursday afternoon as the combination of these warmer temperatures and winds along with dry conditions will bring a threat of wildfires. Temperatures will remain well above average and in the upper 60s to low 70s for the Upper Midwest southwest through the central Plains Friday while an incoming cold front will bring much cooler Fall temperatures to the northern Plains, as highs drop back into the 40s and 50s. Temperatures overall will moderate throughout the eastern U.S. and especially along the northern tier of the country on Saturday making for a pleasant start to the weekend. Forecast highs in the 60s and low 70s will stretch from New England and the Northeast west through the Midwest, northern Plains/Rockies, and into the Pacific Northwest. Temperatures will return into the 70s for the South as well. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php