12:45 PM | "Home Run Weather" app index a perfect 10 out of 10 for tonight's home run derby in New York City

Discussion

The annual Major League Baseball (MLB) Home Run Derby will take place tonight in New York City at the Mets Citi Field ballpark and the “Home Run Weather” app index is a perfect 10 out of 10 so expect some impressive distances as the balls will fly. Temperatures will climb this afternoon into the mid-to-upper 90’s in the New York City metro region with full sunshine and high humidity. By the time the derby begins, temperatures will remain at lofty levels in the upper 80’s and the excessive humidity will no doubt be sticking around.

For its first couple of years, Citi Field was one of the toughest parks for hitting home runs (28th and 27th respectively out of 30 MLB parks), but then they moved the fences in before the 2012 season and now the park is in the middle of the pack in the National League (NL) and 12th overall. Specifically, the first half of the season saw an average of 1.89 home runs per game at Citi Field which placed the stadium exactly in the middle of the 15 NL parks. The average home run distance for the first half of this season was just a hair under 400 feet (399.9). The longest home run hit in Citi Field so far this season was 453 feet by Marlon Byrd of the Mets on June 16th – a distance very likely to be surpassed tonight at the derby thanks in large part to the hot, humid weather conditions. Last year's home run derby winner was Prince Fielder and he also hit the longest drives of the night (twice) at 476 feet. The longest home run ever hit in the home run derby was 528 feet by Sammy Sosa in 2002.

For more info on the app visit the "home run weather" page.

7:00 AM | *The hottest week of the summer*

6-Day Forecast

Today

Sunny, hot, humid, highs in the mid 90’s

Tonight

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

Tuesday

Mostly sunny, hot, humid, mid 90’s

Tuesday Night

Partly cloudy, warm, low 70’s

Wednesday

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

Thursday

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

Friday

Mainly sunny, hot, humid, mid 90’s

Saturday

Mainly sunny, hot, chance for a shower and thunderstorm, low 90’s

Discussion

This week will be the hottest week of the summer so far and perhaps turn out to be the hottest stretch all summer long as there are some signs for cooler-than-normal weather during the latter part of July and during the month of August. A strong Bermuda high pressure system has expanded to the west in the last 24 hours and high pressure will dominate the scene around here at all levels of the atmosphere over the next several days. Highs will reach the mid 90's today and generally stay at or slightly above those levels for the rest of the week along with plenty of sunshine each day. One final note, the "home run weather" app index is a 10 out of 10 for tonight's home run derby in New York City - the ball should be flying!

Video

httpv://youtu.be/JRGkTQMOIjg

1:05 PM | Rain has been localized so far, but the cool temperatures prevail throughout the region

Discussion

Rain fell across southern and central Chester County this morning as well as in Delaware County where more than 2 inches quickly accumulated causing flash flooding problems; however, Philadelphia, Bucks and Montgomery Counties have been spared from anything significant and it appears that this trend will continue for the next couple of hours. On the New Jersey side of the Delaware River, the rain has had trouble advancing north of a line that extends roughly from Philly to Atlantic City. As the afternoon progresses; however, there will be a tendency for the rain to expand to the north and west into Philly, Montgomery and Bucks Counties and central New Jersey. The heaviest precipitation over the past several hours has occurred over the Chesapeake Bay and Delmarva Peninsula where more than 5 inches has been reported in many places (e.g., Kent Island) and it continues to pour in that area. In the DC region, rainfall amounts have been highly localized with near 4.5 inches of rain reported at Dulles Airport since midnight, but only 1.33 inches at nearby Reagan National Airport.

While the precipitation pattern with this system has been rather localized so far, the cool temperatures are being experienced in all areas. E-NE winds have helped to reduce temperatures throughout the Mid-Atlantic region to below normal levels and that trend will continue into tomorrow. Mid-day temperatures in Philly are in the upper 70’s and the normal for this time of year is about 87 degrees for highs. In DC, the noon reading of 72 degrees at Reagan National Airport is far below today’s normal high temperature of 89 degrees. Much warmer conditions will return to the entire Mid-Atlantic region early next week as the Bermuda high re-establishes itself in the area.

7:00 AM | Stalled cool front brings soaking rain and below normal temperatures to the region

6-Day Forecast

Today

Cloudy, much cooler, humid, periods of rain and maybe a couple of thunderstorms, some of the rain will be heavy, highs in the upper 70's degrees (normal high is 89 degrees)

Tonight

Mostly cloudy skies, chance for evening showers, cool, lows in the upper 60’s

Saturday

Partly sunny, still comfortable temperatures, chance for a shower or thunderstorm, low 80’s

Saturday Night

Partly cloudy, mild, lows in the lower 70’s

Sunday

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

Monday

Partly sunny, very warm, near 90

Tuesday

Mainly sunny, hot, low 90's

Wednesday

Mainly sunny, hot, low 90's

Discussion

A cool front passed through the region on Thursday and has stalled nearby and this will generate periods of rain in the region today, some of which will be heavy, as well as high temperatures well below normal for this time of year. The Bermuda high pressure system sitting offshore will re-establish itself early next week by extending to the west and this will generate a warming trend and produce increasing amounts of sunshine.

Video

httpv://youtu.be/dcBgBH0cY34

7:00 AM | Occasional showers and maybe a few thunderstorms into tomorrow as cool front approaches region and stalls; below normal temperatures to close out the week

6-Day Forecast

Today

Mostly cloudy this morning with occasional showers, partly sunny this afternoon with a thunderstorm possible, continued warm and humid, highs in the mid 80’s

Tonight

Showers and thunderstorms likely; otherwise, mostly cloudy skies, muggy, turning slightly cooler late, lows in the mid-to-upper 60’s

Friday

Mostly cloudy, cooler, showers still likely and maybe a thunderstorm, low 80’s

Friday Night

Partly cloudy, mild, shower cannot be ruled out, lows near 70

Saturday

Partly sunny, comfortably warm, cannot rule out a shower or thunderstorm, low-to-mid 80’s

Sunday

Partly sunny, warm, cannot rule out a shower or thunderstorm, mid 80’s

Monday

Mainly sunny, very warm, upper 80’s

Tuesday

Mainly sunny, very warm, upper 80’s

Discussion

A cool front now crossing the western part of Pennsylvania and eastern Ohio will continue to generate occasional showers around here during the morning hours and an afternoon thunderstorm could form. It’ll turn cooler behind the front on Friday and Saturday, but the frontal system will stall right near the coastline as it runs into an atmospheric brick wall known as the Bermuda high. This will allow for the threat of showers and thunderstorms to continue in the region on Friday and Saturday while on the cool (i.e., western) side of the front. By early next week, the off-shore Bermuda high pressure system will tend to re-establish itself westward into the region generating hotter conditions with plenty of sunshine.

Elsewhere, the former Tropical Storm Chantal indeed weakened considerably after crossing over the "rough terrain" islands of the Caribbean Sea over the past 24 hours and it no longer attains "tropical storm" status. There is a chance that the remnants of Chantal, now north of the islands and primarily over open waters, could gain back some strength as the remains head towards the Bahamas so we'll continue to monitor it. Also, somewhat unusual for this time of year, scattered showers and thunderstorms have converged on southern California as a strong disturbance passes overhead.

Video

httpv://youtu.be/aFXh6szkeYE

1:15 PM | 100 years ago today in Death Valley, California the highest temperature ever recorded

Discussion

Today’s forecast high temperature for Death Valley, California is a rather pedestrian 120 degrees. Exactly one hundred years ago today, on July 10th 1913, the weather observer at Greenland Ranch in Death Valley recorded a high temperature of 134 degrees. This is the highest air temperature ever reliably recorded on Earth, but it didn’t get that distinction until just recently. The Greenland Ranch weather station was located across the street from what is known today as the Furnace Creek Ranch and it is about 180 feet below sea level.

Death Valley National Park is the largest national park in the continental US and is located in the Mojave Desert of southeast California. It contains a vast range of elevations and landscapes and is known for being a land of extremes including its climate. In fact, the depth and shape of Death Valley contribute greatly to its extreme heat. Specifically, the extreme heat is due to a combination of several factors including the elevation below sea level, the lack of vegetation especially on the lowest part of the valley floor which allows sunlight to directly heat the desert surface, the narrow width of the valley and its north-south orientation which traps air in the valley allowing it to be recycled back down to the valley floor, radiation of heat from the rocky surfaces of the mountains that surround the valley, and the low humidity as dry air heats at a much quicker rate than moist air. Temperatures in Death Valley normally reach or exceed 100 degrees from Mid-May until early October.

During July of 1913, Death Valley endured an intense stretch of hot weather from the 5th through the 14th when the high temperature reached 125 degrees or higher each and every day. In fact, this 10 day stretch ranks as the hottest stretch of weather ever recorded in Death Valley. The hottest days in this stretch occurred from the 9th through the 13th when the high temperature reached at least 129 degrees with the hottest being on July 10th when the record-breaking 134 degrees was measured.

And now for an interesting recent twist to the story. The Death Valley record of 134 degrees was less than a decade old when it fell to a new record. On September 13, 1922, a temperature of 136 degrees was recorded at El Azizia, Libya and this was indeed cited by the World Meteorological Organization (WMO) for nine decades as the world’s highest temperature ever recorded. However, on September 12, 2012, the WMO officially re-certified the 134 degree reading of July 10th 1913 at Death Valley as the all-time highest air temperature ever recorded on Earth after evidence surfaced suggesting the Libya record of 136 degrees was based on a reading from a bad thermometer which was placed in the wrong place (near asphalt) and, in addition, read by an untrained observer.

This particular example of the rewriting of weather history actually cites the many difficulties of comparing high temperature records of today to those from decades ago. One important problem has to do with the fact that many official weather stations have had significant growth in development (housing, roads, concrete, asphalt, etc.) in the immediate regions surrounding the stations. This urban development very likely contributes to some of today’s warmth (“heat island effect”) at many locations; especially, in the Southwest US where populations have doubled or tripled in the past 50 years near official weather stations (e.g. Las Vegas, Phoenix) making record high temperature records of today in those locations somewhat dubious. Even the inhospitable region of Death Valley has had some development in the area surrounding the Furnace Creek weather station with asphalt roads leading to the nearby visitor’s center - all of which makes this long-surviving 100-year old record of 134 degrees very impressive indeed.

7:00 AM | More showers and thunderstorms as cool front heads eastward towards the region

6-Day Forecast

Today

Partly sunny, very warm, humid, showers and thunderstorms possible from mid-morning on through the afternoon, some of the rain can be heavy and some of the storms can be strong, highs in the upper 80’s

Tonight

Evening showers and thunderstorms possible; otherwise, mostly cloudy skies, muggy, mild, lows near 70 degrees

Thursday

Partly sunny, warm, humid, showers and thunderstorms likely, some of the storms can be strong, mid 80’s

Thursday Night

Evening showers and thunderstorms possible, muggy, turning cooler late, lows in the mid-to-upper 60’s

Friday

Partly sunny, more comfortable, cannot rule out a shower or thunderstorm, mid 80’s

Saturday

Partly sunny, comfortable temperatures, cannot rule out a shower or thunderstorm, mid 80’s

Sunday

Partly sunny, warm, cannot rule out a shower or thunderstorm, mid-to-upper 80’s

Monday

Partly sunny, very warm, humid, chance for a shower or thunderstorm, upper 80’s

Discussion

A cool front approaching from the Midwest will continue our threat for showers and thunderstorms right through tomorrow and some of the storms that form can get quite strong. It’ll turn cooler behind the front in the Friday, Saturday, Sunday time period, and a shower or thunderstorm cannot be completely ruled out on any of those three days. Elsewhere, Tropical Storm Chantal continues to churn over the Caribbean Sea and, should it survive its trek over the island of Hispaniola, Chantal will likely close in on the east coast of Florida and the Bahamas by the weekend.

7:00 AM | Continued threat for showers and thunderstorms; update on the tropics

6-Day Forecast

Today

Partly sunny, very warm, humid, showers and thunderstorms likely, highs in the upper 80’s

Tonight

Evening showers and thunderstorms possible; otherwise, mostly cloudy skies, muggy, mild, lows in the lower 70’s

Wednesday

Partly sunny, hot, humid, showers and thunderstorms likely, some of the storms can be strong, near 90

Wednesday Night

Evening showers and thunderstorms possible, muggy, mild, lows in the mid 70’s

Thursday

Partly sunny, warm, humid, showers and thunderstorms likely, some of the storms can be strong, mid-to-upper 80’s

Friday

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

Saturday

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

Sunday

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

Discussion

A cool front will approach the region at mid-week and this will enhance our threat of showers and thunderstorms on Wednesday and Thursday. It’ll turn slightly cooler behind the front late this week and into the weekend, but the a shower or thunderstorm cannot be completely ruled out at this time. Elsewhere, Tropical Storm Chantal is continuing on a west-to-northwest path with 50 mph sustained winds, and it will cross the Lesser Antilles Islands today and move over the Caribbean Sea. It appears that the next move for Chantal will be over the "tough terrain" of Hispaniola island on Wednesday and, if it survives that trek, the storm will likely reach the Bahamas by Friday.

Video

httpv://youtu.be/P9y3tujmSto

12:40 PM | Tropical Storm Chantal heads for the Caribbean

Discussion

It has been quiet in the Atlantic Basin since mid-June with respect to tropical systems, but now Chantal has reached tropical storm status and is churning towards the Caribbean Sea at a pretty good clip. Chantal developed from a strong easterly wave that slipped off the African west coast a few days ago in what is likely to be a pattern that is frequently repeated over the next few months. The 11AM readings on Chantal have sustained winds at 45 mph with gusts to 60 and rapid movement to the west-northwest at 25 mph. An index that we track here at thesiweather.com called the Madden-Julian Oscillation (MJO) is quite supportive of an active period into at least mid-July as the index will remain in territory (i.e., phases 2 and 3) that favor Atlantic Basin tropical activity. The MJO is a tropical disturbance that propagates eastward around the global tropics with a cycle on the order of 30-60 days.

All indications suggest Chantal will reach the Caribbean Sea within the next 36 hours and then approach the island of Hispaniola later this week. A track over this island would likely, at least temporarily, prevent or slow down intensification of Chantal as mountain peaks tend to interrupt the low-level circulation flow (10,000 foot peaks in Dominican Republic). By the weekend, Chantal could very well be in the vicinity of the Bahamas and, ultimately, it could have an effect on the Southeast US.

7:00 AM | The return of the daily threat for showers and thunderstorms; tropics alive again

6-Day Forecast

Today

Partly sunny, hot, humid, showers and thunderstorms possible, highs near 90

Tonight

Mostly cloudy skies with an evening shower and thunderstorm possible, muggy, mild, lows near 70 degrees

Tuesday

More clouds than sun, very warm, humid, chance for showers and thunderstorms, near 90

Tuesday Night

Evening showers and thunderstorms possible, muggy, mild, lows in the low 70’s

Wednesday

Partly sunny, hot, humid, showers and thunderstorms likely, near 90

Thursday

Partly sunny, not as hot, humid, showers and thunderstorms likely, mid 80’s

Friday

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

Saturday

Partly sunny, warm, humid, chance for a shower or thunderstorm, low 80’s

Discussion

High pressure off the east coast will continue to pump the area with tropical air generating the threat for an occasional shower and thunderstorm. High temperatures will not be quite as excessive during the first half of the week as they were during the weekend with highs not far from 90 degrees and then low 80's are likely for highs at the end of the week. A cool front will enhance the shower and thunderstorm threat on Wednesday and Thursday and slightly cooler air will follow by Friday.

Elsewhere, the tropics have come alive again as Chantal has reached tropical storm status in the Atlantic. It will move rather quickly on a general west-northwest track over the next several days likely reaching the vicinity of near Cuba by the end of the week.

Video

httpv://youtu.be/6MmzHH8TKzA