National Weather Summary for Thursday, May 5, 2016
by David Moran, on May 5, 2016 11:34:18 AM
Localized flooding will be possible on Thursday across portions of the Virginias and North Carolina. Severe thunderstorms will be possible across the Pacific Northwest on Thursday and the Intermountain West on Friday. Heavy rain will be possible for the Northern Rockies and Northern Plains on Friday. Severe thunderstorms will be possible across portions of the Plains on Saturday.
Showers and thunderstorms are expected across Region 1 throughout the day as a surface low moves slowly across the region. Due to the slow movement of the low, multiple rounds of rain will be possible. General rainfall amounts of 0.75-1.50 inches are expected with locally higher amounts in excess of 2 inches possible. This may lead to localized flooding in some areas.
Severe Thunderstorms Possible for the Northwest on Thursday
Thunderstorms are expected to develop ahead of a cold front moving through the Pacific Northwest this afternoon and continue through the evening. As thunderstorms develop, hail and gusty winds will be the primary threats. Activity should weaken by late evening with the loss of daytime heating.
SPC Convective Outlook for Thursday
Severe Thunderstorms Possible for Intermountain West on Friday
A large upper level system is expected to move onto the West Coast on Friday, allowing for the potential for thunderstorms across the Intermountain West during the afternoon and evening. A few strong to severe thunderstorms will be possible, with hail and gusty winds the main threats.
SPC Convective Outlook for Friday
Heavy Rain and Flooding Possible for Portions of the Northern Rockies and Northern High Plains on Friday
A developing surface low will likely generate periods of showers and thunderstorms across portions of the Northern Rockies and Northern High Plains Friday afternoon and evening. General rainfall amounts of 0.50 to 1.50 inches with locally higher amounts in excess of 2.5 inches will be possible. Runoff in the higher elevations and flash flooding in the lower elevations will be possible.
Total Precipitation through Midnight MDT Saturday
Severe Thunderstorms Possible for Great Plains on Saturday
A large upper level low pressure system will begin to transition into a potent upper level trough on Saturday as it continues moving across the western US. At the surface, a low pressure area is likely to deepen in the lee of the Rockies, with an associated warm front extending eastward across the Central Plains and a southward extending dryline developing throughout the day across the southern High Plains. North of the low pressure center and along the warm front, scattered thunderstorm activity will likely develop during the afternoon and evening hours. This will be the area with the highest threat of severe storms, and damaging winds, large hail, and even a few tornadoes will be possible. To the south and along the dryline across western portions of the Texas and Oklahoma, the severe threat will be more conditional. However, at least isolated severe thunderstorms will be likely to develop. Low-level moisture is expected to be somewhat limited in this region for Saturday, so storms will mostly be elevated in nature with damaging winds and large hail the main concerns.
Thunderstorm Risk Outline