Heavy to excessive rainfall is expected across Arizona through Wednesday as deep tropical moisture associated with the remnants of Rosa move northward. There will be a risk for excessive rainfall across the Four Corners region through Wednesday as an upper level trough moves onto the West Coast. Thunderstorms are forecast to develop across Ohio, Pennsylvania, and New York on Tuesday ahead of a cold front.
US Hazards
Excessive Rainfall for Arizona through Wednesday
Deep tropical moisture associated with the remnants of Rosa will impact Arizona in the form of heavy rain over the next couple of days. Flooding is already being reported over southwest Arizona, and this area of heavy rain will slowly shift northward over the next 48 hours. Widespread rainfall accumulations of 2-4 inches can be expected over southern and western Arizona with locally higher amounts in excess of 6 inches. Flash flooding is likely, in addition to a risk for mudslides.
Major Cities in Region: Phoenix, AZ, Flagstaff, AZ
Rainfall Accumulation through Wednesday
Potential for Excessive Rainfall through Wednesday across the Four Corners Region
There will be a risk for isolated flash flooding across the Four Corners region through Wednesday as an upper level trough moves into the region. This trough will interact with tropical moisture, allowing the development of thunderstorms with rainfall rates in excess of an inch per hour. This will allow for a quick 1-2 inches within the heaviest storms, leading to isolated flash flooding.
Major Cities in Region: Durango, CO
Rainfall Accumulation through Wednesday
Thunderstorms for Ohio, Pennsylvania, and New York on Tuesday
Strong to severe thunderstorms are expected to develop over portions of the Upper Ohio Valley and into the Northeast on Tuesday. Morning thunderstorms will gradually diminish, but conditions will become favorable for severe thunderstorm development during the afternoon. Scattered thunderstorms will likely develop along and ahead of a cold front over the Upper Ohio Valley. Thunderstorms will track eastward with a potential for strong to damaging winds, isolated hail, and a tornado or two.
Major Cities in Region: Cleveland, OH, Pittsburgh, PA, Buffalo, NY, Syracuse. NY, Albany, NY, Philadelphia, PA, New York, NY
Thunderstorm Risk for Tuesday
Risk for Thunderstorms Wednesday across the Desert Southwest
Strong to severe thunderstorms are expected to develop across portions of the Desert Southwest on Wednesday, including southern Nevada, southwest Utah, and western Arizona. An upper level trough will move into the Southwest US during the day, allowing for the development of thunderstorms during the late afternoon and evening. Initially, storms will be supercellular with large hail, damaging winds, and tornadoes all potential hazards. Into the evening, the primary hazard will become damaging winds as storms move eastward.
Major Cities in Region: Las Vegas, NV, St. George, UT, Phoenix, AZ, Flagstaff, AZ
SPC Convective Outlook for Wednesday
Thunderstorm Potential from the Central Plains into the Upper Midwest on Wednesday
There will be a potential for severe thunderstorms across portions of the Midwest and Central Plains on Wednesday. An area of low pressure will develop, aiding in streaming warm, moist air northward. A cold front will move southward and will be the focus for isolated to scattered thunderstorm development. Storms are expected to develop during the mid to late afternoon. Primary hazards will be hail and damaging winds, but a few tornadoes cannot be ruled out as storms begin to develop.
Major Cities in Region: Lincoln, NE, Omaha, NE, Des Moines, IA, Minneapolis, MN, Waterloo, IA, Cedar Rapids, IA, Davenport, IA, Madison, WI, Green Bay, WI, Milwaukee, WI
SPC Convective Outlook for Wednesday
Thunderstorms Thursday from the Midwest into the Mississippi Valley
Thunderstorms may develop over the Mid Mississippi Valley on Thursday. A cold front will stall across the region as an area of low pressure develops over the High Plains. Scattered showers and thunderstorms may develop along the front during the afternoon hours. There will be a low risk of hail and damaging winds with the stronger storms that develop.
Major Cities in Region: Dodge City, KS, Wichita, KS, Topeka, KS, Omaha, NE, Kansas City, MO, Des Moines, IA, Davenport, IA, Springfield, IL
SPC Convective Outlook for Thursday
Tropical Update
Tropical Storm Leslie (green oval) is 520 miles east of Bermuda and is moving southwestward at 8 mph. A slow south-southwestward or southward motion is expected through Wednesday with a turn toward the north expected late Wednesday into Thursday. On Friday, a turn toward the north-northeast is expected. Maximum sustained winds are at 65 mph with higher gusts. Leslie is expected to become a hurricane tonight or on Wednesday.
A broad area of low pressure located over the southwestern Caribbean (red oval) is producing disorganized showers and thunderstorms. Some gradual development of this system may occur late this week and this weekend while it drifts northward.
Enhanced Infrared Satellite
A Look Ahead
Showers and thunderstorms may extend from the Central Plains into the Great Lakes on Friday ahead of a cold front. Additional activity may develop on Saturday. By Sunday, an upper level system may bring snow to portions of the Central Rockies. Elsewhere, showers and thunderstorms will extend from the Southern Plains into the Great Lakes. Thunderstorms will continue across the Central and Southern Plains on Monday.