Weather across America

(NATIONAL) A warming trend for the East, much cooler temperatures from the Rockies into the Northern and Central Plains, heavy rains possible across the Southwest and Florida, and widespread heavy rain and flooding threat developing from the Southern to Central Plains into the Mid Mississippi Valley. 

Significant changes to the large scale flow pattern expected over the next few days, with very active heavy rain potential in several sections of the nation.  The deep upper trof that has kept temperatures well below average over the past several days across the eastern U.S., will be pushing off the East coast late Monday into Tuesday.  This will be replaced by a building upper ridge and support much warmer temperatures for the early and middle part of the new week for most areas to the east of the Mississippi river.

The building upper ridge across the East will be the northern component of a developing rex block along the east coast.  The southern portion of this block will be comprised of a developing upper low across the central to eastern Gulf and Florida.  This upper low, and a stationary frontal boundary at the surface across central Florida will support heavy rain potential for central to southern Florida over the next few days.  Much of Florida is coming out of the dry season with severe to extreme drought conditions, with the upcoming heavy rain potential much welcomed hydrologically.  This heavy rain potential will also pose a flooding threat, primarily in the urbanized areas of central to southern Florida over the next few days.

Across the middle portion of the nation, big temperature changes also on tap with much cooler temperatures developing from the Rockies into the Plains over the next few days.  This will be in response to a strong cold front pushing east into the Northern Plains tonight and Monday, southward into the Central Plains by early Tuesday and into the Southern Plains by Wednesday.  This front will be the focus for an expanding area of heavy rains as above average moisture values from the sub-tropical eastern Pacific are drawn northeastward along this frontal boundary.  

This northeastward push of above average moisture values will initially produce heavy rains and localized flooding threats from late Sunday afternoon into Monday across the Southwest into the eastern Great Basin and Southern to Central Rockies.  This above average moisture will then stream northeastward along the above mentioned strong front, supporting an expanding area of heavy rain potential late Monday through Tuesday across the Central to Southern Plains.  These heavy rains will bring some drought relief to portions of the Central Plains and additional heavy rains over the Southern Plains into the Mid Mississippi Valley that have seen much above average precipitation over the past month.  The heavy rain threat across the Central to Southern Plains will also be accompanied by an increasing severe weather threat, with high winds and large hail the greatest severe weather threat, with a lesser threat of tornadoes.