7:00 AM | A change in air mass will be quite noticeable by tonight with lowering humidity and cooler conditions

6-Day Forecast

Today

Mostly cloudy and more comfortable with lowering humidity, still warm, cannot rule out a shower or thunderstorm, highs in the mid 80’s

Tonight

Mostly cloudy, pleasantly cool, maybe a shower or two, lows in the low 60’s

Thursday

Variable clouds, comfortable, cannot rule out a few showers, near 80

Thursday Night

Mostly cloudy, cool, maybe a few showers, low 60’s

Friday

Variable clouds, still comfortable, cannot rule out a few showers, low 80’s

Saturday

Partly sunny, comfortably warm, maybe a shower or thunderstorm, low-to-mid 80’s

Sunday

Mostly cloudy, comfortably warm, chance for showers and thunderstorms, low-to-mid 80’s

Monday

Partly sunny, comfortably warm, maybe a shower or thunderstorm, low-to-mid 80’s

Discussion

A cool front is moving through the region this morning and the change in air mass will be quite noticeable with lowering humidity and cooler temperatures. The front will stall out along the east coast and this may allow for some moisture to back into the region on Thursday and Friday in the form of clouds and perhaps showers. There is even the chance for a nor'easter type of system to form by Friday that would mostly affect New England and its chances for development will be aided by some very warm waters sitting off the New England coastline. Around here, the greatest chance for showers over the next couple of days will be towards the Eastern Shore, but it'll be a close call along the I-95 corridor. High temperatures today will likely reach the 80's, but may actually hold to near 80 degrees for the next couple of days and there will be good sleeping weather tonight with overnight lows dipping to the near 60 in some N and W suburban locations. The normal high temperature for Reagan National Airport on this date is 88 degrees.

Elsewhere, the Atlantic Ocean tropical scene is getting active again as a wave that moved off the western African coast a couple of days ago has now reached tropical depression status. It very well could become Tropical Storm Dorian over the next day or two as it moves slowly westward across the tropical Atlantic Ocean. It will encounter some dry air in the near term, but should it survive that which is increasingly likely, it could reach the Bahamas or western Caribbean Islands in a week to ten days.

Video

httpv://youtu.be/0kl_7ZCrXI4

1:55 PM | Summer review and near term outlook - the worst of the heat may already be over

Discussion

How do the 50's sound for Wednesday and Thursday nights in the suburbs? While the Mid-Atlantic region just experienced a pretty impressive week-long heat wave, the summer so far has been rather ordinary when it comes to the number of hot days, and it appears that the worst of the heat may already be over. Since the latter part of May and through yesterday, July 22nd, Philadelphia has had 19 days in the 90’s compared to the average of 27 days. DC has had 20 days of 90 degrees or above so far this summer versus an average summer of 36 days by this date. Central Park in New York City, which peaked last week at 98 degrees during the heat wave, has had only 15 days of 90 degrees or above since late May.

One of the factors that is likely inhibiting prolonged excessive heat in the Mid-Atlantic region this summer is the high soil moisture content which remains following the excessive rainfall (~10 inches) that fell during the month of June in DC, NYC, Philly. High soil moisture content can knock off a few degrees from potential high temperatures as some of the sun’s energy is used up in evaporation processes rather than in heating the ground directly which in turn heats the lower atmosphere (i.e., more likely to experience prolonged heat waves in drought conditions).

As far as the rest of the summer is concerned in the Mid-Atlantic region, there are signs pointing to a cooler-than-normal finish to the month of July, and even perhaps a cooler-than-normal month of August. An upper level trough of low pressure will likely prevail in the East over the coming weeks while ridging (and hot weather) dominates in the West. Last week’s heat wave in the Mid-Atlantic may very well have been the hottest weather we’ll experience all summer long in this region.

As far as the tropics are concerned, it is quite unusual to be at this stage of the summer and find that there is no tropical storm in either the Atlantic or Pacific Ocean. It is quite likely, however, that the tropics will become more active in the weeks to come as they’ll typically peak during the month of September.

7:00 AM | Still unsettled today, but a break in the humidity coming during the second half of the week

6-Day Forecast

Today

More clouds than sun, very warm, humid, showers and thunderstorms likely and some of the rain can be heavy at times, highs in the upper 80’s

Tonight

Mostly cloudy, chance for evening showers and thunderstorms, mild, lows near 70 degrees

Wednesday

Partly sunny, becoming more comfortable with lowering humidity later in the day, maybe another shower or thunderstorm, mid 80’s

Wednesday Night

Mostly clear, cooler, lows in the low 60’s

Thursday

Partly sunny, comfortable, slight chance for a shower or thunderstorm at night, low 80’s

Friday

Partly sunny, still comfortable, slight chance for a shower or thunderstorm, low-to-mid 80’s

Saturday

Partly sunny, warm, mid 80’s

Sunday

Mostly cloudy, warm, more humid, chance for showers and thunderstorms, low-to-mid 80’s

Discussion

Unsettled conditions will continue for another day around here with the continued threat for showers and thunderstorms. A cool front will slide through the region by tomorrow morning and this will usher in more comfortable and less humid air for the second half of the week. Temperatures will reach well into the mid and upper 80’s today and tomorrow, but then should stay in the low-to-mid 80’s later in the week along with the lower humidity. There is a slight chance for some more shower activity around here later Thursday into Friday and again later in the weekend.

Video

httpv://youtu.be/O8sF9YanOQ8

7:00 AM | Extreme heat is gone, but humidity remains with unsettled conditions and the threat of downpours

6-Day Forecast

Today

Mostly cloudy, warm, humid, showers and thunderstorms likely and any rain that falls can be heavy at times, highs in the mid 80’s

Tonight

Mostly cloudy, showers and thunderstorms likely and any rain that falls can be heavy at times, mild, lows in the low 70’s

Tuesday

Mostly cloudy, very warm, humid, showers and thunderstorms likely and any rain that falls can be heavy at times, upper 80’s

Tuesday Night

Mostly cloudy, showers and thunderstorms likely and any rain that falls can be heavy at times, mild, lows in the low 70’s

Wednesday

Partly sunny, warm, not as humid, still the chance for showers and thunderstorms, mid-to-upper 80’s

Thursday

Partly sunny, warm, slight chance for a shower or thunderstorm, low-to-mid 80’s

Friday

Mostly sunny, pleasant, low-to-mid 80’s

Saturday

Partly sunny, warm, mid-to-upper 80’s

Discussion

The extreme heat of last week is gone and there is no extreme heat in sight. In fact, I believe it is quite likely that when the summer is all over we'll look back at last week as the hottest week of all. The heat wave peaked at 97 degrees at Reagan National Airport, and at 98 degrees in both Philly (Philly Intl Airport) and New York City (Central Park). While the extreme heat is gone, the high humidity from last week remains for the next couple of days and an occasional tropical-like downpour will likely be the result. The frontal system that passed through the region this weekend breaking the back of last week’s heat wave has set up shop in the neighborhood and this will keep it very until settled right through tomorrow with the occasional shower and thunderstorm. Although much of the time will be rain-free over the next couple of days in the Mid-Atlantic, any rain that falls can quickly bring heavy rain and flash flooding to localized regions.

Looking ahead to the second half of the week, a cool front slides through the region by Wednesday and this frontal system passage will set us up for a couple of relatively nice days on Wednesday and Thursday with a noticeable drop in humidity levels. The nicer weather could actually last into Friday, but more rain will likely threaten the Mid-Atlantic region later this weekend.

Video

httpv://youtu.be/4DbJX_dCaUg

3:45 PM | Weekend frontal passage breaks the back of the heat wave and may just return us to a wet pattern

Discussion

From hot, humid and generally rain-free to warm, humid and wet…a cool front is heading towards the east coast and it will break the back of the current heat wave this weekend in the Mid-Atlantic region, but it will also have another important impact on the overall weather pattern. Once the front grudgingly slides through this weekend, it is very likely to stall out just to the south and this could very well lead to a prolonged period of a moist, southwesterly flow of air in the region. In other words, the frontal passage may return us to the type of weather pattern that we experienced before this week’s heat wave - wet and tropical-like.

There will be scattered showers and thunderstorms this evening in the Mid-Atlantic region and more numerous tomorrow afternoon and evening as the cool front reaches the eastern states. Any storm that forms during the next 24 hours or so can be on the strong-to-severe side with heavy rain and gusty winds. The threat for showers and thunderstorms will not end, however, once the front slides through the region. Showers and thunderstorms cannot be ruled out of any day’s forecast for perhaps the next week or so and there is likely to be some heavy rainfall along the way in this new “old” weather pattern - and just when the grass was finally slowing down.

7:00 AM | 100 degrees possible today, but heat wave breaks this weekend; storm threat increases for today and Saturday

6-Day Forecast

Today

Mostly sunny, hot, humid, scattered afternoon showers and thunderstorms are possible, some of the storms can be strong, highs near 100 degrees

Tonight

Chance continues for evening showers and thunderstorms and some of the storms can be strong; otherwise, partly cloudy skies, warm, lows in the upper 70’s

Saturday

Partly sunny, hot, humid, showers and thunderstorms likely during the afternoon, some of the storms can be strong, low-to-mid 90’s

Saturday Night

Evening showers and thunderstorms likely and some of the storms can be strong; otherwise, mostly cloudy skies, warm, low 70’s

Sunday

Mostly cloudy, not as warm, still the chance for a few showers and thunderstorms, upper 80’s

Monday

Partly sunny, warm, chance for showers and thunderstorms, mid 80’s

Tuesday

Partly sunny, warm, chance for showers and thunderstorms, mid 80’s

Wednesday

Partly sunny, warm, chance for showers and thunderstorms, upper 80’s

Discussion

Reagan National Airport reached 95 degrees yesterday and today has a decent shot at triple digits with the record high for the date being 103 degrees set in 1887. While today will feature more excessive heat and humidity similar to recent days, there will also be a greater threat for showers and thunderstorms during the late afternoon and early evening hours. Any storm that forms can get quite strong with heavy rainfall and gusty winds. A cool front approaches on Saturday and showers and thunderstorms are likely tomorrow afternoon and evening and any storm that forms can be on the strong side once again. The front should slide by just to our south by early Sunday paving the way for more comfortable temperatures with highs confined to the mid-to-upper 80’s early next week. This frontal system; however, will stall nearby and showers and thunderstorms cannot be ruled out on Monday, Tuesday or Wednesday.

Video

httpv://youtu.be/KveITlJnuLE

7:00 AM | *Heat wave breaks this weekend as cool front passes through the region*

6-Day Forecast

Today

Mostly sunny, hot, humid, isolated afternoon showers and thunderstorms are possible, highs in the mid-to-upper 90’s

Tonight

An isolated evening shower and thunderstorm possible; otherwise, mostly clear skies, warm, lows in the mid 70’s

Friday

Mostly sunny, hot, humid, scattered afternoon showers and thunderstorms possible, mid-to-upper 90’s

Friday Night

An evening shower and thunderstorm possible; otherwise, partly cloudy skies, warm, low-to-mid 70’s

Saturday

Partly sunny, hot, humid, showers and thunderstorms likely during the afternoon and evening hours, some of the storms can be strong, low-to-mid 90’s

Sunday

Partly sunny, cooler, still the chance for a shower or thunderstorm, mid 80’s

Monday

Partly sunny, comfortable, mid 80’s

Tuesday

Partly sunny, still pretty comfortable temperatures, mid 80’s

Discussion

Relief is in sight for the Mid-Atlantic region from this week’s heat wave as a cool front will slide through the region by Sunday and high temperatures on Sunday afternoon are likely to hold in the mid 80’s. High temperatures today and Friday will likely reach the mid-to-upper 90’s along with ample amounts of sunshine and high humidity levels. The threat for showers and thunderstorms will increase gradually between today and Saturday from “isolated” amounts today to “scattered” amounts on Friday and then to “numerous” levels on Saturday. In fact, some of the storms that do form on Saturday associated with the cool frontal system may be on the strong-to-severe side in the Mid-Atlantic region.

Video

httpv://youtu.be/HzuN7q10RtI

11:15 AM | Global sea ice areal extent currently running near normal; northern hemisphere continues below normal, but southern hemisphere almost at record high sea ice areal extent for the date

Discussion

The areal extent of northern hemisphere sea ice continues to run at below normal levels, but this is being compensated by above normal readings in the southern hemisphere so that the current global sea ice areal extent is relatively close to normal.

Sea ice occupies about 7% of the surface area of planet Earth and is especially important in polar regions. Even though sea ice is found predominately in polar regions, it does have an influence on global climate as its bright surface reflects much sunlight back into space. The North Pole region is considerably different than the South Pole in that up north there is an ocean (Arctic) that is surrounded by land whereas down south there is land (continent of Antarctica) surrounded by ocean. The Arctic responds much more directly to changes in air and sea-surface temperatures than does Antarctica.

The below normal trend for northern hemisphere sea ice began in the mid-90’s which is about the same time the northern Atlantic Ocean entered a warm (positive) phase. Northern Atlantic Ocean sea surface temperatures are tracked by meteorologists through an index called the Atlantic Multidecadal Oscillation (AMO). Specifically, sea-surface temperatures in the north Atlantic have been generally running at above normal levels since the mid 90’s and this is quite likely having an influence on the northern hemisphere sea ice areal extent. Oceanic cycles can last two or three decades and it is likely that when the AMO returns to a cold (negative) phase the sea ice in the Arctic region will return to normal or above normal levels on a consistent basis similar to what occurred prior to the mid-90’s.

Meanwhile, way down south the sea surface temperatures have been running below normal in recent times in those areas surrounding the continent of Antarctica and this is likely contributing to the above normal levels of sea ice in that part of the world. In fact, the southern hemisphere sea ice area has been generally above normal for the last several years it is very close to a record high for this time of year (second only to 2010) when compared to all years going back to 1979 which is when satellite-era data records began for global sea ice.

Video

httpv://youtu.be/EtPqhR56HLY

7:00 AM | Heat wave continues, but relief arrives by Sunday with cool frontal passage

6-Day Forecast

Today

Mostly sunny, hot, humid, highs in the mid-to-upper 90’s

Tonight

Mostly clear, warm, lows in the mid 70’s

Thursday

Mostly sunny, hot, humid, an isolated late day thunderstorm, mid-to-upper 90’s

Thursday Night

An isolated evening shower or thunderstorm; otherwise, mostly clear skies, warm, mid-to-upper 70’s

Friday

Mostly sunny, hot, humid, scattered late day showers and thunderstorms possible, mid-to-upper 90’s

Saturday

Partly sunny, hot, humid, showers and thunderstorms likely later in the day and/or at night, some of the storms can be strong, low 90’s

Sunday

Partly sunny, cooler, still the chance for a shower or thunderstorm, mid 80’s

Monday

Partly sunny, comfortably warm, mid 80’s

Discussion

The hottest week of the summer will continue into the weekend, but there is relief in sight as a cool front will slide through the region late Saturday and temperatures on Sunday are likely to hold in the mid 80’s. High temperatures for the next few days will reach the mid-to-upper 90’s along with copious amounts of sunshine and relatively high humidity levels. An isolated afternoon or evening shower and thunderstorm cannot be ruled out on Thursday and scattered showers and thunderstorms are possible later Friday, but the best chance for these will occur later Saturday with the approach of the cool front and some of the storms that form on Saturday can get quite strong.

Video

httpv://youtu.be/5v3g_OmkzHg

7:00 AM | The hottest weather of the summer continues, but relief is in sight

6-Day Forecast

Today

Mostly sunny, hot, humid, highs in the mid-to-upper 90’s

Tonight

Mostly clear, warm, lows in the mid 70’s

Wednesday

Mostly sunny, hot, humid, mid-to-upper 90’s

Wednesday Night

Mostly clear, warm, mid-to-upper 70’s

Thursday

Mostly sunny, hot, humid, an isolated late day thunderstorm, mid-to-upper 90’s

Friday

Mostly sunny, hot, humid, chance for a shower and thunderstorm, mid 90’s

Saturday

Partly sunny, hot, humid, showers and thunderstorms late in the day or at night and some of the storms can be strong, low 90’s

Sunday

Partly sunny, cooler, chance for a shower and thunderstorm, mid 80’s

Discussion

The hottest week of the summer will continue uninterrupted through the week, but there is relief in sight. A cool front will approach the region from the Great Lakes on Saturday enhancing our chances for showers and thunderstorms by then and some of the late day storms can be strong. Canadian-born high pressure building in behind the front on Sunday will likely hold our high temperatures to the mid 80’s to close out the weekend.

Video

httpv://youtu.be/FNF_J-9IGgY