Share

Weather Pattern Does a Flip in the East

Chris Dolce
Published: July 23, 2013

The weather pattern in the upper atmosphere from around the Mississippi River eastward is doing a complete reversal from what we saw last week.

Upper pattern evolution.

Animation shows the weather pattern evolution from a hot area of high pressure late this past week to a dip in the upper wind flow in the coming week.

The big dome of high pressure that brought sweltering temperatures from the Upper Midwest to the Great Lakes and Northeast for many days has been replaced by a southward dip in the upper-level wind flow. In meteorological terms, the hot "ridge" of high pressure is being replaced by a "trough".

With all of this going on in the atmosphere above us, what does it mean for where we live at the surface? We have good news and bad news. Let's start with the good news first.

Good News: Temperatures More Comfortable

Background

Tuesday's Highs

Tuesday's Highs

Tuesday's Highs

Tuesday's Highs

When we see a trough in the upper atmosphere, that usually means cooler temperatures.

That's exactly what we will see over the next several days with temperatures generally hovering near or slightly below late-July averages from the Upper Midwest to the Great Lakes, Ohio Valley and Northeast.

From Minneapolis to Chicago and Boston, this means highs will mostly be in the 70s and 80s into at least Thursday. Temperatures will also stay at a reasonable level for this time of year in the Southeast with highs peaking in the 80s in most locations, though a few places may touch the low 90s.

(HIGHS: Tue | Wed | Thu)

For parts of the Midwest and interior Northeast, low temperatures will cool off nicely as well. This will especially be true by mid-week and on through Friday as a second push of cooler air moves into the region. Parts of northern Wisconsin, northern Michigan and northern New England could dip into the upper 40s on a few mornings later this week.

(MORNING LOWS: Wed | Thu | Fri)

The I-95 Northeast urban corridor from New York City southward will finally feel relief at night, with morning lows in the 60s likely by Thursday morning.  This will bring Philadelphia's now record-breaking streak of 29 consecutive nights at or above 70 degrees to an end.

(MORE: Your Local Forecast)

Bad News: Stormy at Times

Background

Tuesday's Forecast

Tuesday's Forecast

Tuesday's Forecast

Tuesday's Forecast

Embedded in the trough that is taking over the eastern third of the nation will be impulses diving south and eastward periodically.

These impulses of energy will provide lift in the atmosphere to help spark scattered showers and thunderstorms each day.

Rain chances will exist on one or more days in portions of the Mississippi Valley, Great Lakes, Ohio Valley, Southeast, Middle Atlantic and Northeast regions. That said, not every location will see rain each day.

Some of the storms could produce locally heavy rainfall, flash flooding and gusty winds.

For a look at where storms chances will be the greatest each day, you can click on the day-by-day forecast map links below.

(RAIN THREAT: Tue | Wed | Thu | Fri | Sat | Sun)

PHOTOS: Middle July 2013 Heat Wave in the East

Kids cool off in the spray of an open hydrant on a hot evening in Lawrence, Mass. on July 16, 2013. (AP Photo/Elise Amendola)


Featured Blogs

Heavy Rains From 99L Drench Belize and Mexico

By Dr. Jeff Masters
August 31, 2014

Tropical wave 99L is spreading heavy rains over Belize and Mexico's Yucatan Peninsula as the storm heads west-northwest at about 10 mph. Conditions are favorable for development, but 99L will not be able to develop until it finishes crossing Mexico's Yucatan Peninsula and emerges into the Gulf of Mexico's Bay of Campeche on Monday.

Death Valley ‘Sliding Rocks’ Mystery Resolved

By Christopher C. Burt
August 29, 2014

An article published in the science journal PLOS ONE on August 27th by scientists from the Scripps Institution of Oceanography has finally put to rest the mystery of the ‘sliding’ rocks of Racetrack Playa in Death Valley.

Live Blog: Tracking Hurricane Arthur as it Approaches North Carolina Coast

By Shaun Tanner
July 3, 2014

This is a live blog set up to provide the latest coverage on Hurricane Arthur as it threatens the North Carolina Coast. Check back often to see what the latest is with Arthur. The most recent updates are at the top.

Tropical Terminology

By Stu Ostro
June 30, 2014

Here is some basic, fundamental terminology related to tropical cyclones. Rather than a comprehensive and/or technical glossary, this represents the essence of the meaning & importance of some key, frequently used terms.

2013-14 - An Interesting Winter From A to Z

By Tom Niziol
May 15, 2014

It was a very interesting winter across a good part of the nation from the Rockies through the Plains to the Northeast. Let's break down the most significant winter storms on a month by month basis.

What the 5th IPCC Assessment Doesn't Include

By Angela Fritz
September 27, 2013

Melting permafrost has the potential to release an additional 1.5 trillion tons of carbon into the atmosphere, and could increase our global average temperature by 1.5°F in addition to our day-to-day human emissions. However, this effect is not included in the IPCC report issued Friday morning, which means the estimates of how Earth's climate will change are likely on the conservative side.