Cooler Than Normal Temperatures Build Today

General Overview: A ACTIVE WEATHER PATTERN WILL UNFOLD ACROSS MUCH OF THE NATION OVER THE COMING DAYS AS A SERIES OF LOW PRESSURE SYSTEMS AND ASSOCIATED FRONTAL BOUNDARIES DRIVE PRECIPITATION ACROSS MULTIPLE REGIONS. THE MOST SIGNIFICANT WEATHER STORY EARLY IN THE PERIOD WILL BE A WELL-ORGANIZED LOW PRESSURE SYSTEM TRACKING THROUGH THE GREAT LAKES, BRINGING RAIN TO THE UPPER MIDWEST AND GREAT LAKES REGION ALONG WITH RAIN AND THUNDERSTORMS ACROSS THE CENTRAL AND SOUTH CENTRAL PORTIONS OF THE COUNTRY. A COLD FRONT SWEEPING EASTWARD WILL PUSH ACTIVE WEATHER INTO THE NORTHEAST AND MID-ATLANTIC BY MIDWEEK. MEANWHILE, THE PACIFIC NORTHWEST AND NORTHERN ROCKIES WILL SEE ROUNDS OF RAIN AND MOUNTAIN SNOW AS ADDITIONAL DISTURBANCES MOVE ONSHORE. A BROAD WARMING TREND WILL TAKE HOLD ACROSS THE WEST AND EVENTUALLY SPREAD EASTWARD THROUGH THE LATTER HALF OF THE FORECAST PERIOD, WITH ABOVE-NORMAL TEMPERATURES BECOMING WIDESPREAD ACROSS THE NATION BY DAYS 7-10.

—

EAST: The early part of the period will be dominated by a low pressure system tracking through the Great Lakes region, producing widespread rain showers across the Upper Midwest, the Great Lakes states, and into portions of the Northeast. This system will be a significant late-season snow producer, with heavy snow accumulations possible across the northern Great Lakes and into New England. A warm front associated with this system will help drive a rain and thunderstorm threat across the Ohio Valley and into the Mid-Atlantic during Tuesday evening, with activity pushing further east through Wednesday. By Wednesday evening, the low will be positioned near the Great Lakes with an occluded front wrapping back to the south and a warm front extending into the Northeast, keeping rain and thunderstorm chances elevated from the Mid-Atlantic northward through New England. Rain will be widespread along the immediate Atlantic Seaboard as a cold front sweeps through the region. A high pressure system situated offshore will help funnel moisture into the region ahead of the front. By Thursday evening, a new low pressure system develops off the Northeast coast, with a cold front pushing well offshore and a warm front extending back to the southwest. Rain will continue along coastal areas, with lingering shower activity possible across the interior Northeast. By Friday, the Northeast coast low will be pulling away, with a cold front sweeping through and rain transitioning to a drying pattern across much of the region. The Southeast will remain relatively quiet through much of the period, though thunderstorm activity will be possible along the Gulf Coast early in the period, with a cold front eventually pushing through the region by late week.

Temperature Anomalies:

-Days 1-3: Temperatures will run 6 to more than 12 degrees below normal across the Great Lakes and into the Northeast, particularly on Days 1 and 2, as cold air filters in behind the departing low. The Mid-Atlantic will also see below-normal readings of around 3 to 6 degrees. The Southeast and Gulf Coast will be near to slightly below normal.

-Days 4-6: Below-normal temperatures will persist across the Great Lakes and Ohio Valley, running roughly 6 to 9 degrees below average on Day 5, before gradually moderating. The Southeast will begin a warming trend, trending back toward near-normal or slightly above by Day 6.

-Days 7-10: A broad warming trend takes hold, with temperatures climbing to 3 to 6 degrees above normal across much of the East, including the Mid-Atlantic, Southeast, and Ohio Valley. The Northeast will also trend above normal by the end of the period.

—

CENTRAL: The central United States will be one of the most active regions during the forecast period. On Tuesday evening, a low pressure system over the Central Plains will have a cold front extending southwestward and a warm front pushing northeastward, generating a swath of rain and thunderstorms from the Central Plains northward through the Midwest and into the Great Lakes. Snow will be falling across the northern tier, particularly across the Upper Midwest and into the Great Lakes, where heavy accumulations are possible. By Wednesday evening, the cold front will have pushed eastward, with high pressure building into the Central Plains and bringing a drying trend to much of the region. However, thunderstorm activity will continue to be possible across the South Central states as moisture lingers ahead of the departing front. By Thursday evening, a new low pressure system develops over the Northern Plains, with a cold front dropping southward and a warm front pushing northeastward. Rain and thunderstorms will be widespread across the Central Plains and into the Midwest, with snow possible on the northern edge of the precipitation shield across the Northern Plains and into the Upper Midwest. The Rocky Mountain region will see scattered rain and snow showers, particularly at higher elevations. By Friday evening, the Central Plains low will be tracking northeastward, with a cold front sweeping through the region and triggering another round of rain and thunderstorms from the Central Plains through the Midwest and into the Great Lakes. Snow will again be possible across the Northern Plains on the back side of this system. Critical fire weather conditions will be a concern across portions of the Southern Plains and Southwest early in the period, given dry and windy conditions.

Temperature Anomalies:

-Days 1-3: Temperatures across the Central Plains and Midwest will be near to slightly below normal early, with some pockets of 3 to 6 degrees below normal across the Upper Midwest. The South Central region will be near normal to slightly below normal.

-Days 4-6: A warming trend will develop across the Central Plains and Midwest, with temperatures climbing to 6 to more than 12 degrees above normal across portions of the Central Plains by Days 5 and 6. The North Central region will also trend warmer, running 6 to 9 degrees above normal.

-Days 7-10: Above-normal temperatures will be widespread across the central United States, with anomalies of 3 to 9 degrees above normal from the Central Plains through the Midwest and into the Great Lakes. The warming trend will be well-established across the entire central tier by the end of the period.

—

WEST: The western United States will see an active pattern early in the period, with a series of low pressure systems moving onshore from the Pacific. On Tuesday evening, a low pressure system off the Pacific Coast will bring rain to coastal areas of the Pacific Northwest, with snow possible in the higher elevations of the Cascades and northern Rockies. Scattered rain and thunderstorm activity will be present across portions of the Southwest and into the Desert Southwest. By Wednesday evening, additional disturbances will continue to push onshore, bringing more rounds of rain and mountain snow to the Pacific Northwest and northern Rockies, with rain and thunderstorm activity persisting across the Southwest. By Thursday evening, the Pacific Northwest will continue to see rain and mountain snow, with the precipitation shield expanding southward into portions of the northern California coast. The Intermountain West will see scattered rain and snow showers, particularly at higher elevations. Thunderstorm activity will continue across portions of the Southwest and into the Desert Southwest. By Friday, the pattern will remain active across the Pacific Northwest, with additional rounds of rain and mountain snow expected. Critical fire weather conditions will be a concern across portions of the Southwest and into the Southern Rockies early in the period.

Temperature Anomalies:

-Days 1-3: A significant warm anomaly will be in place across much of the West, with temperatures running 6 to more than 12 degrees above normal across the Desert Southwest, the Great Basin, and into the Intermountain West. The Pacific Northwest will be near to slightly above normal. Some pockets of below-normal temperatures will be present across the higher elevations of the Rockies.

-Days 4-6: The above-normal temperature signal will remain strong and expansive across the West, with anomalies of 6 to more than 12 degrees above normal persisting across the Desert Southwest, Great Basin, and Intermountain West. The warming will begin to spread northward into the Northern Rockies and Pacific Northwest.

-Days 7-10: The warm anomaly will gradually moderate across the West but will remain above normal across much of the region, with anomalies of 3 to 6 degrees above normal. The Pacific Northwest will trend closer to near normal by the end of the period.

—

TROPICAL: The Atlantic and Eastern Pacific basins are both quiet at this time, with no tropical cyclone activity expected during the next seven days. No areas of concern for tropical development are being monitored in either basin.