100+ Heat Indices in Northern New England

Yesterday's high temperatures of 97° at both Concord, New Hampshire and Portland, Maine both fell short of records set in 1977, but heat indices have already reached 100 or more in northern New England by noon today. Here are some reports from Maine and New Hampshire:

Location           Temperature Dewpoint Relative Heat   
                                        Humidity Index    
Portland               95         69        42    100
Sanford                97         72        44    105
Wiscasset              95         72        47    103
Rockland               93         73        52    102
Portsmouth             97         71        43    105
Nashua                 98         69        38    104
Manchester             96         68        39    101  

To the south, both Boston and New York are at 98° with heat indices of 107 and 108, respectively. Central Park in New York has a temperature of 100° and dewpoint of 76° for a heat index of 114.

Minneapolis Humidity Reaches (Unofficial) Record;Confirmation Confounded by Political Kerfluffle

Image (click to enlarge): Dewpoint temperature at 3 pm CDT, July 19,2011, from Unisys

The National Weather Service reported on Tuesday (July 19) that the Minneapolis dewpoint reached an unofficial record of 82°, resulting in near-record heat index values. The Minnesota State Climatology Office, which could confirm the record, remains closed as a result of a state budget political showdown, now in its third week.

THE DEW POINT TEMPERATURE AT THE MINNEAPOLIS ST PAUL INTERNATIONAL
AIRPORT WAS 82 DEGREES ON THE 3 PM AND 4 PM OBSERVATION. THIS IS THE
HIGHEST DEW POINT TEMPERATURE REPORTED ON AN HOURLY OBSERVATION AT
THE MINNEAPOLIS ST PAUL INTERNATIONAL AIRPORT SINCE HOURLY DEW POINT
RECORDS BEGAN IN 1945.

THE PREVIOUS HOURLY DEW POINT RECORD WAS 81 DEGREES...WHICH WAS SET
ON JULY 30TH 1999. A DEW POINT OF 81 DEGREES WAS ALSO REPORTED AT
THE AIRPORT ON SUNDAY...MONDAY...AND EARLIER TODAY /JULY 17-19/.

THE MINNESOTA STATE CLIMATOLOGY OFFICE IS THE OFFICIAL SOURCE OF
DEW POINT RECORDS ACROSS THE STATE. THIS NEW RECORD WILL BE
CONSIDERED UNOFFICIAL UNTIL IT IS CONFIRMED BY THE STAFF AT THE
STATE CLIMATE OFFICE.  

Tropical Development Possible, but DC Impact Likely Minimal

Now

Hot, humid. As temperatures climbed to the 90s in most parts of the metro area this afternoon, dewpoints were in the muggy low 70s at many locations. Dulles reached 92° by 3pm, and the humidity was producing a heat index as high as 96° the following hour. Although prolonged hot spells are relatively rare in September, at some point in the past National has observed temperatures in the 90s on every day of the month, and the all-time monthly high of 104° occurred on this date in 1881.

On this 12th consecutive rainless day, however, precipitation prospects from a possible developing tropical system are diminishing.

The area of storms lurking off the southeastern Atlantic coast has become more concentrated today, and a Hurricane Hunter flight investigated the situation this afternoon. As of 5pm, it had not found a closed circulation at the surface, but it was continuing to collect data. If a depression or tropical storm does develop, the most likely scenarios at this point are for it to move northwestward, weaken and dissipate over eastern North Carolina or for it to be swept out to sea ahead of a cold front moving eastward on Sunday.

Mediaorology

The scheduled topic for this weekend's Forecast Earth on The Weather Channel (5pm Saturday and Sunday) is "Paying For Climate Change", but the broadcast may be pre-empted for tropical coverage.

Swinging for the Record Books: Heat on Steroids

**Heat Advisory in Effect Until 8 PM This Evening **

Now

Sunny, record heat, humid. Unhindered by the clouds of yesterday and helped by a drying westerly breeze, the sun went to bat today chasing a long-standing temperature record. The temperature rose several degrees an hour through the morning, as much as 5° between 9 and 10 am, and by 1:03, the National Airport temperature hit 102°, breaking the record for the date set in 1930. After retreating several degrees temporarily, the temperature was back up to 101° at 4pm. Except for the 97° at 2pm, the reading at National has been at or above 100° for 5 consecutive hours.

Records were also set at both of the other major airports: at least 100° at Dulles and 102° at BWI. Several records were set or tied elsewhere in Virginia as well: Richmond 102°, Danville 100° (tied), Blacksburg 91° (tied).

Humidity is also quite high, although the 8 hours of greater than 75° dewpoints overnight were replaced by readings near or below 70° this afternoon. When combined with the hot temperatures, however, the heat index reached at least 108°. Scattered locally severe thunderstorms fired up in the early afternoon between Pittsburgh and Morgantown WV, but these have so far remained over and west of the mountains.

CapitalWeather.com chart from NWS data, photo © Kevin Ambrose

Tonight and Tomorrow

Hot, humid, scattered thunderstorms possible. Very warm and humid conditions will continue overnight with only a slight chance of scattered thunderstorms through this evening. Lows will be mainly in the upper 70s to near 80° in town and some mid 70s in the 'burbosphere. Tomorrow will be mostly sunny and not quite as hot with highs 93-97° and only a 20% chance of afternoon or evening thunderstorms.

For the outlook through the rest of the week and the weekend, scroll on down to Dan's post below.

Climate Corner

While today's WaPo featured the current heat wave on the front page, inside the A section was an article, "Across Globe, Extremes of Heat and Rain", about a just-released World Meteorological Organization report on recent extreme weather events throughout the globe. Although any individual weather event cannot be directly tied to climate change, widespread extremes are certainly consistent with such a scenario.

Also on today's WaPo front page was an article, "Warming Draws Evangelicals Into Environmentalist Fold", about the developing collaboration between evangelical groups and the environmental movement.

High Summer

**Heat Advisory in Effect Until 8 PM This Evening, 1 PM to 8 PM Wednesday **

Now

Hazy, hot, humid. High summer had many residents of the Washington metro area feeling "down, low down" today, but the most hyped extremes of heat failed to materialize as the core of the heat wave remained to the south and west of the region. At mid afternoon, Culpeper had the lone triple-digit temperature, but the 104° heat index there was exceeded by the 109° reading at Fredericksburg resulting from a 97° temperature/75° dewpoint.

In the immediate vicinity of the Beltway, temperatures at post time are generally in the mid 90s. Thunderstorms on radar are mainly limited to Pennsylvania, although a scattered and weakening line extends through eastern West Virginia.

Very hot temperatures and uncomfortable humidity will continue through at least tomorrow, with one major model predicting a high of 103°.

Tonight and Tomorrow

Hot, humid, scattered thunderstorms possible. There is a very slight chance of an isolated thunderstorm through this evening; otherwise, it will be another warm and sticky night with lows dipping into the upper 70s downtown and the lower 70s in the 'burbs. Tomorrow will be continued hot and humid with highs 96-101° and heat indices as high as 105-107°. There is only a slight chance of an afternoon or evening thunderstorm.

For the outlook through the rest of the week, scroll on down to Jason's post below.

Tropical Topics

Although several typhoons have been active in the Pacific recently, the tropical Atlantic remains quiet.

The Miami Herald and the Palm Beach Post both reported today on the news we posted yesterday regarding the suggestion that ousted National Hurricane Center Director Proenza return to his old job in Texas.

Mediaorology: "Sultry 24/7"

Yesterday's New York Daily News TV section featured a review of The Weather Channel's female talent (Alexandra Steele, Heather Tesch, Stephanie Abrams, Nicole Mitchell).

Alexandra Steele photo from The Weather Channel

DC: Dewpoints Climbing

** Heat Advisory in effect noon to 8pm Tuesday **

Now

Hazy, hot, humid. Yesterday's showers varied widely in amount across the region, from zero in parts of Northern Virginia to over an inch in some eastern locations. (The green areas through much of Prince George's County range from 0.5" to as high as 1.5", while the blues through much of the District and Montgomery County are less than 0.5", and most of Fairfax County is less than 0.1".)

The additional moisture, however, has helped lift dewpoints into the sultry low 70s, a level which pushes the heat index up about 7 or 8 degrees from the temperatures in the low 90s. Both Ft. Belvoir and Manassas were sporting heat indices of 100° by 2pm, and Ft. Belvoir was the hot spot at 4pm with an index of 103°. By mid afternoon, however, radar showed only a few isolated showers, mostly southward along I-95.

Hot temperatures and uncomfortable humidity are likely to continue through the middle of the week.

Chart of 24-hr. precipitation through 8am this morning from NWS Southern Region.

Tonight and Tomorrow

Hot, humid, scattered thunderstorms possible. There is still a slight chance of an isolated thunderstorm through this evening; otherwise, it will be a warm and sticky night with lows barely getting into the upper 70s downtown and the lower 70s in the 'burbs. Tomorrow will be continued hot and humid with highs 95-99° and heat indices approaching 105°. There is only a slight chance of an afternoon or evening thunderstorm.

For the outlook through the rest of the week, scroll on down to Jason's post below.

Tropical Topics

The tropical wave which tracked westward through the Caribbean late last week has pushed onward into Central America without developing.

As the Proenza affair at the National Hurricane Center continues to unfold, the House Committee on Science and Technology announced today that the chairmen of 2 subcommittees have sent a letter to NOAA Administrator Lautenbacher requesting that Proenza be returned as Director of the NWS Southern Region if he is permanently removed from his post at the NHC. According to the letter, NOAA had planned to assign Proenza as training chief of the Office of Climate, Water and Weather Services, a "drastic demotion", before the NHC assessment team had even been formed. An article in Friday's Miami Herald reviews Proenza's campaign to get his job back.

The paper by Holland and Webster on "Heightened Tropical Cyclone Activity in the North Atlantic" which PM Update posted on last Monday has been referenced in the Science Notebook of today's WaPo, but without the crucial caveat that this issue is far from settled because of the limitations of the available data.

It's August. It's DC. Get Used To It.

Now

Sunny, hot, moderately humid. Temperatures are in the low to mid 90s throughout the Washington metro area this afternoon, while dewpoints are near to slightly below the August average of 66°, so heat indices are mostly within a degree or two of the actual temperature. Leesburg was the local hot spot at 4pm with 97°, but the heat index was only 96°. Except for some very isolated showers in the mountains, radar is clear for several hundred miles.

Hot temperatures and seasonable humidity are likely to continue into the weekend.

Tonight and Tomorrow

Crank up the AC. Tonight will be mostly clear and quite warm with lows in the low 70s to near 75° in the city and some upper 60s in the 'burbs. Tomorrow will be sunny, hot, and seasonably humid with highs 93-96° and a very slight chance of late day thunderstorms.

For the outlook through the the weekend and beyond with Larson's Long-Range, scroll on down to Josh's post below.

Tropical Topics

The tropical wave which is now over the eastern Caribbean was looking more impressive on satellite images today, but was still disorganized. It still has some potential for development. A Hurricane Hunter plane was enroute early this afternoon to investigate.

Another area of interest is a batch of showers in the northern Gulf of Mexico.

The AP is reporting (via WaPo, for some odd reason under a "Global Warming" link) that "Ex-Hurricane Center Chief Wants Job Back". Ousted Director Proenza's lawyers are alleging in an 11-page letter that he was illegally fired.

Mediaorology

The Weather Channel's Dr. Heidi Cullen was interviewed ("Into the Limelight, and the Politics of Global Warming") in Tuesday's New York Times about her career in climate research and reporting.

Photo courtesy New York Times.

Heat Index: High, Not Horrendous

Now

Sunny, hot. It could be worse: Temperatures are in the mid to upper 90s this afternoon, but dewpoints generally in the low 60s and even some upper 50s have kept heat indices mostly out of triple digits. By late this afternoon, all 3 major airports in the region had reached at least 96°. The relatively moderate humidity means that already parched lawns and gardens are likely to continue turning brown for at least another day, however.

Heat relief on tap by Thursday should last into the weekend.

CapitalWeather.com chart from heat index equation at zunis.org

Tonight and Tomorrow

Hazy, hot, increasing humidity. Under mostly cloudless but hazy skies tonight, lows will be in the upper 70s downtown and in the upper 60s to low 70s in the 'burbs. Tomorrow will be continued hazy and hot, but with gradually increasing humidity and highs again in the upper 90s. Heat indices will be near 100.

For the outlook through the rest of the week and into the weekend, scroll on down to Jason's post below.

Staying Cool: WaPo Chat

Join us tomorrow at 2pm for a live discussion on the heat at the online WaPo.

Mediarology: Tornado Diary

The first show in a 3-part BBC-produced series, "Tornado Diary", will appear on WETA-TV, Channel 26, at 9pm tomorrow. The first episode, "Oklahoma City", focuses on the notorious F5 storm of May 3, 1999 (also excellently described by local author Nancy Mathis in "Storm Warning"). The program will be repeated Thursday at 1am and Sunday at 5pm. The other 2 episodes will be shown on succeeding Tuesdays.

Climate Clues

A tip of the Rabett ears for a pointer to an important article scheduled to appear tomorrow in the Proceedings of the Royal Academy. The paper, by M. Lockwood and C. Frohlich, was featured as a news item in the July 5 issue of the journal Nature. It is described as "the final nail in the coffin for people who would like to make the Sun responsible for current global warming." Based on solar data for the last 100 years, the authors were able to show that recent trends in solar activity are actually opposite to those required to explain global warming. The results are also discussed in the UK Guardian.

DC: DisComfort

Now

Partly sunny, warm, muggy, some storms. It's another muggy afternoon in the Washington metro area with some popup thunderstorms already appearing earlier. After reaching at least 93° by 1pm, National's temperature retreated to 82° the following hour in a very light thunderstorm, but Dulles surged ahead to 95° by mid afternoon. To the south, traditionally warm Fredericksburg combined a dewpoint of 75° with a temperature of 99° to get a sweat-soaked heat index of 111.

At post time, the only warnings in effect were marine warnings for Chesapeake Bay and severe thunderstorm warnings in south-central and southwestern Virginia. No watches were posted. Here at Update Central in west-central MoCo, a slight rumble of thunder has just begun. After another day of discomfort, more pleasant conditions are in prospect for the upcoming weekend.

Tonight and Tomorrow

Chance of evening storms, continued muggy. Showers and thunderstorms will be scattered across the region (30% chance at any given location) through this evening. For the rest of tonight, warm and humid conditions will continue with lows in the mid 70s downtown and the low 70s in the 'burbs. Tomorrow will be hot and humid with highs generally 90-94° and thunderstorms likely, some possibly severe, in the afternoon and evening.

For the outlook through the rest of the week and the weekend, scroll on down to Dan's post below.

Climate Corner

If you're confused (or just curious) about some of the claims that have been made regarding the atmospheric thermodynamic effects of increasing CO₂, check out the latest post at RealClimate.org by Spencer Weaert, called "A Saturated Gassy Argument".

The Weather Channel's Forecast Earth blog had a post yesterday by our own Andrew Freedman on the Emily Yoffe WaPo op-ed cited earlier by Dan.

Drought Watch

A June 22 article in The Week magazine, "Desperate for Water", surveys the effects of long-term drought in the western U.S.

Some Say "Sultry," Many Mutter "Muggy"

Now

Mostly sunny, warm, muggy. Whether you call it "sultry," "muggy," or "yucky," classic DC heat and humidity are back in the Washington metro area: temperatures mainly in the upper 80s, dewpoints pushing into the 70s. Late this afternoon, Culpeper's readings of 90° (temperature) and 72° (dewpoint) produced a heat index of 97, while a southerly river breeze kept the National Airport official temperature and dewpoint to 87° and 69°, respectively, for a more bearable heat index of 91.

After several days of discomfort, more pleasant conditions are predicted for next weekend.

Tonight and Tomorrow

Chance of evening storms, continued muggy. There is a 30% chance of scattered thunderstorms through this evening, mainly to the south and west of the immediate metro area. Warm and muggy conditions will prevail overnight with lows from the low 70s downtown to some upper 60s in the 'burbs. Tomorrow will be hazy, warm, and humid with a 25% chance of afternoon or evening thundershowers and highs 89-93°, heat indices reaching the mid or upper 90s.

For the outlook through the rest of the week, scroll on down to Jason's post below.

Tropical Topics

The UK Met Office last week issued a hurricane season forecast which is considerably tamer than those issued earlier by NOAA and Colorado State. The UK forecast, which is being issued publicly for the first time, uses a dynamical (physical) model of the ocean/atmosphere system, called GloSea, as opposed to the mainly statistical techniques used in other forecasts. The prediction calls for 10 named storms in the July-November period, slightly less than the recent historical average of 12.4.

Climate Corner

In an exclusive report, The Onion last week detailed the Bush Administration's latest climate change program, the NACI (National Air Conditioner Initiative). Bush is quoted as saying,

"Global warming threatens us all, whether we're mowing our lawns, rafting down a river in a national park, or driving to the end of the driveway to get our mail. The task that lies ahead is undeniably hard. But if we do not succeed, we will be profoundly inconvenienced. And I promise you: America will not let that happen."

Graphic courtesy The Onion.

DC Gets Mugged; Thunderstorms Likely

** Severe Thunderstorm Watch in Effect Until 11 PM **

Now

Hot, very humid. OK, it's official, you can start complaining now. With dewpoints in the oppressive 70s, temperatures in the 90s are feeling very uncomfortable in the Washington metro area this afternoon. One of the worst reports in the greater metro region was at 2pm from Fredericksburg, where a dewpoint of 75° combined with an air temperature of 95° to yield a heat index of 107.

A line of thunderstorms forming by mid afternoon in the usual location, just west of I-81, was moving generally northeastward, but it could reach at least the far western suburbs by early evening. A couple of small popup storms were also developing to the east, including one in the far western corner of Montgomery County which has produced some distant rumbles of thunder here at Update Central.

Tonight and Tomorrow

Muggy, thunderstorms likely, then cooler, less humid. The chance of thunderstorms will continue through this evening, especially to the west of the immediate metro area. Lows will be in the low 70s downtown to the upper 60s in the cooler 'burbs. Some clouds and possibly some lingering showers in the morning tomorrow will give way to sunshine in the afternoon and much more pleasant conditions. Highs of 84-87° will be accompanied by much lower humidity.

For the outlook through the rest of the week, scroll on down to Jason's post below.

Mediarology

Today's WaPo salutes the approaching solstice with the return of its series, "Secret Worlds of Summer", in the Metro section. The first installment, "Mysteries of Light", surveys the role of the sun in myth and in local scientific investigations at NIST in Gaithersburg and NASA in Greenbelt.

Got A Ticket to Rise: Heat Advisory Friday

** Heat Advisory in Effect From 2 PM to 8 PM Friday **

Now

Sunny, warmer, more humid. Temperatures have warmed considerably this afternoon in the Washington metro area, but the humidity has increased more; temperatures are about 10° higher than yesterday (mid 80s), but dewpoints are 15° higher (near 60°).

Temperatures and humidities both have a ticket to continue rising through tomorrow as a very strong low pressure area for the season (978 mb this morning) in the upper Midwest helps pump heat and Gulf of Mexico moisture into the region. The heat wave should be short-lived however, with more comfortable conditions returning for the weekend.

Surface weather map at 2pm today from HPC/NCEP/NWS

Tonight and Tomorrow

Becoming hot, humid; late-day storms possible tomorrow. Skies will be mostly clear tonight with warm temperatures and increasing humidity; lows will be from near 70° downtown to the low and mid 60s in the cooler 'burbs. Tomorrow will be sunny, hot, and humid with highs in the mid 90s. Heat index values will be near 100. Severe thunderstorms are a possibility from late afternoon into the overnight hours.

For the outlook through the weekend and beyond with Larson's Long-Range, scroll on down to Josh's post below.

Tropical Topics: Gonu Gone-o

Unusually strong Tropical Cyclone Gonu continued to display an impressive appearance as it weakened to a tropical storm before making landfall in Iran in the early morning hours today. The storm was reported to have killed 28 people and caused significant damage in Oman.

Climate Corner

Today's WaPo carried a page A1 article, "Icy Island Warms to Climate Change", describing the effects of climate change on the 56,000 inhabitants of Greenland.

Meanwhile, at the G8 conference, the U.S. rope-a-dope climate strategy continued, as the final declaration stated, "In setting a global goal for emissions reductions in the process we have agreed today involving all major emitters, we will consider seriously the decisions made by the European Union, Canada and Japan . . ." Environmentalists were "were unimpressed."