Archive for August, 2012

Isaac’s impact on western Mass.
August 26, 2012

By Meteorologist Mike Skurko

Tropical Storm Isaac (soon to be Hurricane Isaac) is expected to make landfall near New Orleans, Louisiana as a Category 2 hurricane on Wednesday morning with winds near 100 mph.  While western Massachusetts will not take a direct hit from this storm like we did Irene a year ago, we may see the remnants of Isaac bring rain to our region about a week from today.

The following is a raw long-range computer model for next Sunday morning.  The top panel shows surface pressure, and easily identifies a low in Ohio (which take my word…looking at all of the previous frames, this low is the continued track of Isaac).  The bottom panel shows 6-hour rainfall totals, which paints a heavy core of rain associated with this low.  Notice how that rain starts to push into the Berkshires on Sunday morning with this particular model.

I have been monitoring these models over the last few days, with updated runs coming in every 6 hours.  While the exact details have varied…exact location, timing, strength…of Isaac remnants, it seems to be gaining validity that we could see some rain delivered by a leftover Isaac sometime late next weekend.  By the end of this week, we will have endured several consecutive dry days, so some steady weekend rain may receive a nice welcome.  Stay posted!

Hurricane Andrew 20th Anniversary
August 25, 2012

By Meteorologist Mike Skurko

While all eyes are on South Florida this weekend for approaching Tropical Storm (soon-to-be Hurricane) Isaac, folks across that area are still very mindful that Friday was a significant date in that state’s history.  On August 24, 1992, Hurricane Andrew made landfall just south of downtown Miami, becoming the costliest hurricane in U.S. history at that time…later surpassed by Hurricane Katrina

The link below is a fascinating article by the Miami Herald, interviewing a handful of people effected by the storm when they were very young (including a classmate of mine at Penn State).  Notice how the article begins by saying how residents have “a heightened respect for Mother Nature.  A clenched stomach during a bad thunderstorm.”  Doesn’t that sound a little familiar to how Springfield residents now react after the June 1st tornado?

http://www.miamiherald.com/2012/08/22/2963734/on-the-20th-anniversary-children.html

New record for world’s hottest rain: 115 degrees
August 18, 2012

By Meteorologist Mike Skurko

[Photo courtesy Ken Lund via Flickr]

The small town of Needles, California set a new world record for the hottest recorded temperature while raining…a sizzling 115 degrees!  The small town nestled in the Mojave Desert near the tri-border of California, Nevada, and Arizona recorded light rain beginning at 3:56 pm on Monday when a thunderstorm rolled in despite the excessive heat.

Dr. Jeff Masters, co-founder of the website Weather Underground, explained what caused the rain to fall at such extreme temperatures:

“Monday’s rain in Needles was due to a flow of moisture coming from the south caused by the Southwest U.S. monsoon, a seasonal influx of moisture caused by the difference in temperature between the hot desert and the cooler ocean areas surrounding Mexico to the south.”

Dr. Warren Blier, science and operations officer for the National Weather Service in Monterey, California, adds via facebook:

“Associated weather conditions were perfect for such an event, as maximum diurnal surface heating during a record-level low desert heat wave combined with the arrival of residual raindrops from a dissipating upwind thunderstorm.”

Most of the rain evaporated before hitting the ground, thanks to 11% relative humidity at the time (also a world record for the lowest humidity that rain has ever occurred).  Rain gauges only recorded a trace of precipitation.

The previous record for the world’s hottest rain was 109 degrees in Mecca, Saudi Arabia on June 5, 2012 and in Marrakech, Morocco on July 10, 2010.

This satellite photo courtesy of NASA shows the thunderstorms starting to develop around 1:30 that afternoon.  Notice the Colorado River just east of town, which forms the border of California and Arizona.

Meteorology 101: Cold fronts and south winds
August 17, 2012

By Meteorologist Mike Skurko

Today an approaching low pressure system caused a pretty moderate southwesterly wind to kick in.  That, in turn, brought in slightly warmer temperatures and increased humidity levels into western Massachusetts.  Why does this happen?  It’s not a coincidence that approaching low pressure systems bring in milder, muggier conditions ahead of them.  Our summer weather intern, Rob, from the meteorology program at Lyndon State College explains why:

With an approaching low pressure system on Friday, many people probably noticed that it felt a bit more humid and dew points increased by a couple of degrees.  This is very common in southern New England in the summer months.  High pressure means drier air and sometimes much cooler air, and then it changes ahead of the low pressure.  This is an explanation why we get muggy and uncomfortable ahead of an approaching low.

Low pressure spins counter-clockwise, or cyclonic. When a low pressure system approaches western Massachusetts, we are on the side that has a southerly flow. The southerly flow acts as moisture pump supplying moist air from the Gulf of Mexico and the southern states.  This is why it is very humid out ahead of a low pressure system, until a cold front moves through and the winds shift behind it…supplying more refreshing air.

Bouncing highway sign
August 16, 2012

By Meteorologist Mike Skurko

Youtube video of a highway sign bouncing up and down during a severe storm has gone viral.  The footage comes from Tuesday in Calgary, Canada.

Experts said the bouncing was caused by wind patterns hitting the structure, causing it to “gallop”.  The most spectacular footage of  a similar phenomenon was the collapse of the Tacoma Narrows Bridge in Washington in 1940…swaying and twisting in the wind before falling into the water below.

GOES vs. POES satellites
August 15, 2012

By Meteorologist Mike Skurko

Our last entry here took a look at the new GOES-R satellite, which will be launched and give major advances to hurricane prediction.  GOES satellites are a specific type of satellite that hover at the same position above earth.  Our weather intern, Rob from the meteorology program at Lyndon State College discusses some of the features that make GOES satellites unique:

With hurricane season close to its peak, NOAA is looking to improve hurricane forecasting by launching new satellites. However, all satellites are not the same; some have certain orbits that are useful for the job they perform.  The new GOES-R satellite is a geosynchronous satellite. The NOAA-19 satellite is an example of a polar orbiting satellite.  Here is an explanation of the differences between the two.

The GOES in GOES-R stands for geostationary operational environmental satellite.  What this means is that the satellite stays over one spot 22,300 miles above the earth’s surface.  This is to make sure it stays over the same spot and follow the earth’s surface.  Its job is to monitor any changes in the atmosphere to track severe weather.  The GOES is also the reason why we have satellite loops because it takes pictures constantly to able to look at changes over time.

The NOAA-19 satellite is an example of a polar orbiting satellite (POES). This means that its orbit is north-south going over the poles. Polar orbiting satellites collect data to ensure data isn’t more than six hours old.  They are also used to measure a variety of parameters in the atmosphere.  Polar orbiting satellites provide better coverage of the poles that the GOES can’t get.  It is also a higher resolution because it can orbit at a lower altitude since it is not orbiting at the same speed as the earth’s rotation.

New satellites to help hurricane prediction
August 14, 2012

By Meteorologist Mike Skurko

A few days ago, NOAA updated their hurricane outlook for the 2012 season.  In the near future, the short-term forecasts…i.e. a few days before an actual hurricane strikes…will receive much improvement thanks to new satellites.   The GOES-R satellite will be the first of four satellites launched as part of a new $10.6 billion dollar project.

The new GOES-R satellite will provide forecasters with an image of a hurricane every 30 seconds, not the standard 15 minutes only available right now.  This will give forecasters an incredibly more detailed look at the complex processes within a hurricane…leading to better predictions of rapidly-intensifying, or rapidly-weakening hurricanes before striking onshore.

For a full explanation of the new satellites, as well as comments from hurricane specialists, visit this article from the Sun Sentinel in Fort Lauderdale, FL

http://www.sun-sentinel.com/news/weather/hurricane/fl-new-weather-satellites-20120810,0,7356182.story

Dewpoint vs. Relative Humidity
August 13, 2012

By Meteorologist Mike Skurko

Believe it or not, Monday afternoon’s  temperatures were around the same as this past weekend’s, but it felt a lot more comfortable out there!  Why is that?  The dew point this weekend was around 70 degrees, but Monday’s dew points were in the low-60s.  When we’re talking about humidity, why is the dew point more important than the relative humidity percentage to represent how it feels outside?  Our weather intern Robert Gould from the meteorology program at Lyndon State College explains why:

The dew point is what we concentrate on for how it feels outside, almost like a comfort index.  On-air we say a dewpoint of 60 degrees and below is comfortable and above 70 is oppressive.  The dew point is defined as the temperature that water vapor must be cooled down to for it to condense into water.  This also means that if the air temperature is at the dew point, then the air is saturated…hence the fog you see when you wake up in the morning.  Higher dew points means there is more water vapor in the atmosphere because it won’t take much cooling for water to condensate.

The relative humidity percentage is related to the dew point.  It is also related to air temperature as well.  If the air temperature and dew point are close together, the relative humidity is close to 100%.  If the dew point and temperature are exactly the same, the relative humidity is exactly 100%.  If they are further apart, then the relative humidity is less.

Here is a great example: if the temperature is 88 degrees and the dewpoint is an oppressive 70 degrees, the relative humidity calculates to 54% (through a very complicated mathematical formula).  If the temperature is 80 degrees and the dewpoint is a much more tolerable 62 degrees, the relative humidity is also 54%!  Clearly the first example is a much more uncomfortable and muggy day, despite the relative humidity percentages being equal!  That is why the dew point is better to judge how it feels outside.

NOAA increases hurricane outlook
August 13, 2012

By Meteorologist Mike Skurko

With the peak of hurricane season near, NOAA has increased their forecasted number of tropical storms and hurricanes from their initial outlook in May.  NOAA’s update released on Thursday increased to 12 to 17 expected named storms, with 5 to 8 hurricanes, and 2 to 3 major hurricanes.  Their initial outlook in May called for as little as 9 named storms, and only 1 to 3 major hurricanes.

Experts from NOAA said an active start to the hurricane season historically carries over into a busy season overall.  This was the first hurricane season since 1908 with two named storms before the season even started (June 1), and the first year on record to have four named storms before July.  Forecasters also expect this year’s warmer-than-normal sea surface temperatures to fuel additional activity in the Atlantic.

Meanwhile, while El Nino is expected to form, experts believe it will not strengthen until too late in the season to have much of an impact.  The unique wind patterns from an El Nino typically lead to quieter hurricane seasons…as strong wind shear in the tropics likes to essentially shred the tops of many developing storms.

While we dealt with Tropical Storm Irene last year, there have been cases throughout New England where hurricane history can repeat itself from one year to the very next.

“In 1954 we had the major Hurricane Carol strike New England, and less than a week later we had Hurricane Edna, another major hurricane strike out towards Cape Cod.”  said Glenn Field, meteorologist with the National Weather Service in Taunton, MA.  “Then in 1955, we had Tropical Storms Connie and Diane back-to-back as well.”

The peak of hurricane season is from late August to mid-September.

Microburst in Glastonbury, CT
August 12, 2012

By Meteorologist Mike Skurko

The National Weather Service in Taunton, MA has determined that a microburst hit the town of Glastonbury, CT on Friday…the same storm that issued a tornado warning for the Palmer area that day.  Peak winds were estimated at about 100 mph!  Here is the report issued by the National Weather Service regarding that storm:

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE TAUNTON MA
531 PM EDT SAT AUG 11 2012

...MICROBURST /STRAIGHT LINE WIND DAMAGE/ CONFIRMED NEAR
GLASTONBURY IN HARTFORD COUNTY CONNECTICUT...

LOCATION...GLASTONBURY IN HARTFORD COUNTY CONNECTICUT
DATE...AUGUST 10 2012
ESTIMATED TIME...430 PM 
ESTIMATED MAXIMUM WIND SPEED...100 MPH
MAXIMUM PATH WIDTH...ONE-HALF MILE 
PATH LENGTH...TWO AND ONE-HALF MILES 
FATALITIES...0 
INJURIES...0

THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND PUBLICATION IN NWS
STORM DATA.

...SUMMARY...
THE NATIONAL WEATHER SERVICE IN TAUNTON MA HAS CONFIRMED A
MICROBURST /STRAIGHT LINE WIND DAMAGE/ IN GLASTONBURY IN HARTFORD
COUNTY CONNECTICUT ON AUGUST 10 2012.

THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN TAUNTON CONDUCTED
A STORM SURVEY OF WIND DAMAGE IN EASTERN GLASTONBURY. THE DAMAGE
AREA EXTENDED FROM HOMESTEAD DRIVE...PADDOK STREET AND WASSUC
ROAD TO JUST NORTH OF HEBRON AVENUE. THE HOMESTEAD DRIVE/PADDOK
STREET AND BUTLER DRIVE/NEEDLETREE LANE AREAS EXPERIENCED THE MOST
CONCENTRATED TREE DAMAGE. IN THESE TWO AREAS NUMEROUS TREES WERE
EITHER UPROOTED OR SNAPPED OFF NEAR THE TREE BASE. IN THE BUTLER
DRIVE/NEEDLETREE LANE AREA UPWARDS OF 30 TO 40 TREES WERE UPROOTED
WITH THREE HOUSES SUSTAINING SOME DAMAGE. IN THE BUTLER DRIVE/
NEEDLETREE LANE AREA IT IS ESTIMATED THAT WIND SPEEDS RANGED FROM
85 TO 100 MPH. IN THE AREA OF HOMESTEAD DRIVE AND PADDOK STREET
AREA THE ESTIMATED WINDS RANGED FROM 75 TO 90 MPH. OUTSIDE OF
THESE TWO CORE DAMAGE AREAS THE ESTIMATED WIND SPEED WAS 55 TO 80
MPH.

THERE WAS ALSO CONSIDERABLE TREE DAMAGE AROUND A HOME ON THE SOUTH
SIDE OF WEIR STREET NEAR ROARING BROOK.

THE TREE DAMAGE TAPERED OFF NEAR HEBRON AVENUE WITH ONLY MINOR
TREE DAMAGE AS FAR NORTH AS MOUNTAIN ROAD IN GLASTONBURY. WHILE
THE GREATEST WIDTH OF THE DAMAGE FIELD WAS ABOUT ONE-HALF MILE...
MOST OF THE DAMAGE WAS ONE-QUARTER MILE IN WIDTH. THE CORE OF THE
STRONGEST WINDS WAS 100 TO 200 YARDS WIDE.