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SKYWARNEWS
National Weather Service State College, PA - Spring 2001
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National Weather Service State College, PA - Spring 2001
Dunham retires by Dave Ondrejik
After 33 years of loyal service to the NWS,
Tom Dunham has headed to the greener pastures of retirement.
Tom and Diann Dunham
pose at his retirement party.
Upon graduating from Penn State University
(we won’t mention the year), Tom spent some time in the Navy before entering
the NWS in 1973 in Souix Falls SD.
Within 5 years, Tom moved to Buffalo, NY as a lead forecaster and
eventually became the Deputy Meteorologist-In-Charge for 15 years. As a native
of Eagles Mere PA, Tom took the first opportunity to head south to and help to
spin-up the new office in State College.
Tom will be sorely missed, not only for his
wealth of knowledge and skill, but also for his wonderful personality and
tennis prowess.
Tom – you will be missed throughout Central
Pennsylvania!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
New Warning Coordination
Meteorologist by
Dave Ondrejik
I would like to take this opportunity to
introduce myself as the new Warning Coordination Meteorologist (WCM) at NWS
State College. Although I have been at
the State College office for over 3 years, I had a slightly different focus,
with my main duties as a Hydrologist.
As a native of Johnstown Pa, it has been 11
years since I graduated from Penn State Univ. After graduation, I worked as a
Scientist at the Navy/NOAA Joint Ice Center where I forecast the growth and
decay of sea ice for shipping and navigation purposes. In 1993, I moved to the NWS office in
Columbus Oh, where I worked as a Meteorologist Intern. By the end of 1994 I had moved to the NWS
office in Wilmington, Oh where I specialized in rainfall forecasting for the
Ohio Valley.
After getting an itch to return home, I moved
to the State College office in 1997 as the Service Hydrologist.
I welcome the opportunity to work with this
dedicated group of SKYWARN volunteers.
Recently I received my amateur radio license (K3NWS), and have hopes to
become more involved (personally and professionally) with the amateur radio
groups throughout Central Pennsylvania.
If I can be of any help to you, please don’t
hesitate to contact me at: (814) 234-9412 ext 223 or via e-mail at: david.ondrejik@noaa.gov
Dave
Ondrejik – K3NWS
The Greenhouse Effects and Global Warming by Mike Evans
The sun warms the earth by
radiating energy from space to the earth’s surface. Most of that energy makes it through the earth’s atmosphere and
gets absorbed by the earth’s surface.
The earth is warmed, and some energy from the earth is radiated back
through the atmosphere into space. The atmosphere traps some of the outgoing
energy and is warmed. The natural
trapping of the earth’s outgoing heat energy is known as the “greenhouse”
effect. Therefore, it can be said that
the “greenhouse” effect is a natural phenomenon; without it the earth’s
atmosphere would be too cold to support life.
Gases in the earth’s
atmosphere that act to trap outgoing heat energy include water vapor, carbon
dioxide and methane. Water vapor is by
far the most important of these gasses.
However, another important heat trapping gas in carbon dioxide. Since man’s burning of fossil fuels adds
carbon dioxide to the atmosphere, it is natural to assume that additional
carbon dioxide would mean additional trapping of heat and a warmer
atmosphere. It turns out that the
amount of carbon dioxide that man is adding to the atmosphere is not enough to
directly cause a large amount of atmospheric warming. However, the theory on human-induced “global warming” states that
just a small amount of warming caused by an increase in carbon dioxide could
lead to more warming through a series of positive “feedback” effects. According
to this theory, a small amount of warming leads to increased evaporation of
water, which leads to more atmospheric water vapor. Water vapor is a heat trapping gas, and the result would be a
more significant temperature rise than what would be caused by just increasing
carbon dioxide.
Scientists make predictions
on the potential severity of human-induced “global warming” by running computer
simulations of the atmosphere. These “climate models” factor in most of the
currently known physical properties of the atmosphere, and predict what future
temperature will be based on an increase in carbon dioxide. The most common experiment involves running
these models based on a human-induced doubling of carbon dioxide. The amount of warming depends on the model
that is run. Some models predict as
much as 9 degrees Fahrenheit (F) of warming during the next century, while
other models only predict a few degrees.
A temperature rise of only a few degrees F may not sound like much, but
it should be noted that most of the models forecast the majority of warming to
be over land, and at high latitudes, with less warming for the ocean and
tropical areas. This would translate into much more warming over the United
States. There has been lots of speculation
about what secondary effects a big temperature rise would cause, such as
increased drought, increased flooding, extinction of species, and rising sea
levels.
Plenty of scientific
uncertainties remain with this entire issue.
While some scientists/media have implied that there is a strong
consensus that disastrous global warming is inevitable unless drastic action is
taken, that is not, in fact the case.
Many scientists do believe that a significant warming is highly likely
during the next century, but there are also scientists who believe that little
warming will occur, or at the very least, we do not know enough to make an
accurate prediction.
One issue that needs more
attention is the question about how much human-induced warming has already
occurred. To answer this question, we need to know how much of the recently
observed warming is natural, and how much is man-made. Natural cycles of warming and cooling have
always taken place. Also, we need to know
exactly how much warming has taken place worldwide during the last century. Current estimates are that the earth has
warmed about 0.6 degrees F in the last 100 years. However, accurately measuring the temperature of the earth’s
atmosphere to within a few tenths of a degree is difficult. Potentially inaccurate or incomplete temperature
measurement over the oceans and in under-developed countries, as well as
complications from urban heat islands, makes this a very difficult issue.
Another issue that needs
more attention involves improving the climate models that are making the predictions
of warming. One area of improvement
that is needed is in the area of forecasting atmospheric water vapor and cloud
cover. Another area where new
discoveries are just now being made is in the area of how ocean circulation
cycles can trigger and control climate variations. The accuracy of the models
will improve as more is learned about all of these things.
So, there you have it. I think I will wait around until the year
2350 to see how things work out.
On Saturday, September 29,
the NWS State College office and the Middle Atlantic River Forecast Center will
hold an Open house from 10 am to 3 pm. Tours of both offices will be offered
along with severe weather videos, and explanations on weather and hydrologic
forecasting. Watch our web page (http://www.nws.noaa.gov/er/ctp) for
further information and directions to the office.
Weather Safety on the Internet
As we enter the new severe
weather season, it is time once again to review our weather safety
information. Plenty of information can
be found on our Internet web page at: http://www.nws.noaa.gov/er/ctp/safety.html
Staying calm in a weather
emergency situation is one of the most important factors. Be prepared ahead of time!! Know where to go during a severe
thunderstorm or tornado warning before it is issued. If a flash flood warning is issued and you live near a stream or
river that is expected to flood, have a pre-planned evacuation route.
Know where to go before the
event hits is the key to safely surviving the storm.
This picture of 4
simultaneous tornadoes was taken in Italy in April 2001.
Central Pennsylvania Winter
Summary 2000-2001 by John La Corte
The
winter of 2000-2001 was a remarkable season over much of the northeastern
United States. A marked contrast to the previous two warm and relatively
snow-less winters, this year’s winter saw a return to cold and snow in many
locations. Perhaps the most remarkable aspect of the winter was the late flurry
with which it ended over much of New York and New England. Several coastal
storms resulted in record late season snows. Many sites such as Binghamton and Rochester
New York, Burlington Vermont and Portland Maine all received more snow in March
alone than the reporting sites of central Pennsylvania had all season!
In our area, the traditional winter (December through
February) will go down as a cold and dry one, but the statistics are a bit
misleading.
After starting off the
winter on a particularly harsh note, the months of January and February ended
up rather mild and dry here in central Pennsylvania. Looking at data for
Williamsport and Harrisburg showed that December started off with near record
cold and above normal snowfall. Harrisburg saw the fourth coldest month of
December on record with an average temperature of just 26.5 degrees. This was
more than seven degrees below normal. January and February recovered nicely
however. January temperatures were near or slightly above normal and February
continued the trend ending up much warmer than normal. As well as ending warm,
January and February were drier than normal in Williamsport and Harrisburg.
Averaging as much as 1.5 inches of rain below normal, this equated to snowfall
deficits a little below normal in Harrisburg, to several inches below normal in
Williamsport.
So
while the season’s numbers will record a colder than normal winter, in fact
here in central Pennsylvania it could have been much worse. Our neighbors to
the north got far more use out of their snow shovels. Several stations saw more
than 100 inches of snow, with Buffalo topping the chart with more than 13 feet
of snow!
Improving Our Ability To
Anticipate Tornadic Events by Richard Grumm
In October of 1999, the
National Weather Service office in State College and the Pennsylvania State
University began a program to help forecasters identify significant weather
events.
A web page was established at http://eyewall.met.psu.edu/ At this site, forecasters and “weather
hobbyists” can find a wide range of forecast products. The goal of these products is to help
forecasters identify weather events that have the potential to produce unusual
weather.
In addition to the forecast
products, there is a web page that provides rankings of weather events at http://eyewall.met.psu.edu/ranking/ranking.html.
The rankings include all
weather events since 1 January, 1948 and the page is updated monthly. Events are rated by categories including
the top-20 strongest events of all time and the top ten events for each month
of the year. The domain
includes the eastern United States
and the western Atlantic.
The famous super storm of
March 1993, which produced record snows in Pennsylvania, ranked 3rd
overall and was the single strongest event in the month of March. The late season snowfall of 15-16 May 1976
was associated with 2nd strongest weather event during the month of
May.
The Climatological data can be
used to rank storms and see what conditions looked like during past significant
weather events. The data can also be used to see how the current forecasts
compared to the Climatological data used in the ranking system. Over the past year, we have found that we
can identify many unusual weather events well in advance using the current
forecasts and the climatological data. Using these data, we have identified
some unique characteristics of Pennsylvania tornado events, which could be
identified in model forecasts well in advance of their occurrence.
We have determined that all
large tornado outbreaks appear to be related to the passage of a very strong
surface low across the Great Lakes and a very strong low-level jet. In fact, since 1948, there has not been a
major Pennsylvania tornado outbreak that was not associated with these
features. It is type of information will help us do a better job anticipating
tornado events in the future.
Middle Atlantic River Forecast Center (MARFC) Advanced Hydrologic
Prediction
Services (AHPS) Demonstration Project by Ned
Pryor
Advanced Hydrologic Prediction
Services is a National Weather Service (NWS) program designed to provide
longer-range hydrologic products including flood outlooks, drought products and
water supply guidance. This improved capability builds on the traditional
expertise and responsibility of the NWS flood forecasting program and will
ultimately provide the public, emergency management agencies and water resource
organizations with a wide suite of water resources products.
AHPS forecasts also provide
information about forecast uncertainties, which can be beneficial to
end-users. These longer-range products
will include probabilistic (e.g. there is a 25% chance that the river will
exceed flood stage at a given location during the next 7 days) information,
mostly in graphical format, to describe the likelihood of various hydrologic
scenarios.
MARFC has selected the Juniata
River Basin in south-central Pennsylvania to demonstrate some of the AHPS
capabilities and product formats. The
Juniata River Basin is approximately 3350 square miles above Newport,
Pennsylvania and includes the Frankstown Branch Juniata River, the Raystown
Branch Juniata River, Raystown Dam, the Little Juniata River, Aughwick Creek
and Tuscarora Creek.
Two key programmatic
components need to be in place for AHPS to work in a given watershed.
First, the basin must be
calibrated with a continuous rainfall-runoff model so that the hydrologic
computer model (which incorporates rainfall processing, snow modeling,
rainfall-runoff calculations, evapotranspiration estimates, baseflow runoff,
hydrologic routings, reservoir operations) can be run for extended periods of
time.
Secondly, an NWS program
entitled Ensemble Streamflow Prediction (ESP) must be set up for the basin of
interest so that various probabilistic forecasts of streamflow can be
generated.
The ESP system enables
hydrologists to make longer-range probabilistic streamflow forecasts based on
the current hydrologic conditions (river and reservoir levels, soil moisture
conditions, and the extent and characteristics of any snowpack) along with 40
years of historical temperature and precipitation data. ESP generates one streamflow trace for each
year of historical meteorological data with each model run initiated to the
current basin hydrologic conditions. A
probabilistic forecast is then generated by statistical analysis of the
streamflow traces for the flow variable of interest (maximum flows, minimum
flows, mean daily flow volumes) over the time period of interest.
Examples of AHPS graphical
products include Trace Ensembles, Exceedance Probability Plots and Probability
Interval Histograms. Visit MARFC's website at http://marfchp1.met.psu.edu and
click on "AHPS" to view samples of these AHPS products. Continue to check back during the next
several months as additional AHPS products are developed and posted to the
website.
A new Senior Service
Hydrologist has been hired to watch over central Pennsylvania’s rivers and
streams. Peter Jung has been at this
office for over 8 years, where he has worked numerous flooding and flash
flooding events, including the Jan 1996 flood.
Pete has previously been stationed at the NWS offices in Syracuse, NY
and New York City.
Pete has a wealth of
meteorological and hydrological knowledge and the citizens of central
Pennsylvania will benefit from his experience.
Please join me in congratulating Pete on his selection.
Senior
Service Hydrologist, Pete Jung