Monday, October 19, 2009


Note to students: For this week's assignment, follow these links below. Stay focused, do your best, and if there are any questions about the assignment, I can be reached via this address: Sincerely, Mr. Foot


To get the current El Nino data for this week: click on the last link above, press the "page down" key on your computer until you reach page # 4. There you'll see the current data.


The Foot's Forecast Winter 2009 SYMPOSIUM

What does "December in October"
mean for the Mid-Atlantic region?

SUMMARY: The occurence of 20- to 25-degree below normal temperatures in October may have disrupted the seasonal pattern such that the Eastern United States may not return to long periods of normal weather for several months. The effect of this early cold period now may produce a brief warmup in November followed by a major cold outbreak and an inland snow event. A rapid onset of persistent and disruptive winter weather is expected by December 5. If this unstable pattern continues, as was observed in October-December of 2002, areas of the Mid-Atlantic region could experience widespread school closings for 2 or more days this December. This may equal or exceed the cold and snowy period observed in the Baltimore region from December 4-11, 2002.

PART 1: HYPOTHESIS. The stormy pattern along the Northeast and Mid-Atlantic was transitioned into place by three coastal storms including Tropical Storm Danny during Aug 26-29, rainstorms of 9/6-12 and 9/24-28. The absence of hurricanes in the Gulf of Mexico thus far, combined with a stable El Nino Cycle has produced warmer than normal sea surface temperatures over very large areas. Warmer seas can permit more rapid evaporation of moisture into developing low pressure systems tracking across the southwest and along the southeast. The October 12-13 midwest snowfall, and the October 15-18 Early Autumn storm are indicators of how climate teleconnections are interacting to produce unseasonal regional weather events.

PART 2: CLIMATE DATA Most of us in weather and climate community, either professional, amateur or the public, accept that we may never understand all the factors driving winter patterns. Each year on this website, I attempt to expand the dialogue on those factors based on knowledge gained from research, observations from readers, and simply tracking the data more closely. For this year, the monitoring criteria for a potentially significant winter is much greater than before - so the "laundry list" approach has to be employed for efficiency. Whether you are a frequent or new reader, this data list is designed to familiarize with the acronyms and definitions tracked here. I will be training my Science students to monitor the list in order to provide you with the most spot-on perspective on what may be influencing our weather over the next six months.

A) Hydrosphere Data (Tracking specific cycles, seasonal trends and indices about ocean temperatures and influence on atmospheric activity)

1) ENSO Cycle (+0.7 to +1.0 C as of 10/12/09): defined as current status of the El Nino Southern Oscillation Cycle as reported by the US Climate Prediction Center in a brief diagnostic discussion as well as the weekly ENSO update.

2) PDO Index (positive phase as of 10/8/09): The Pacific Decadal Oscillation is defined as monitoring the "leading principal component of North Pacific monthly sea surface temperature variability (poleward of 20N for the 1900-93 period)." Researchers at the University of Washington suggest that "combining ENSO and PDO information may enhance the skill of empirical North American climate forecasts." Sources: UWA, Climate Impacts Group.

1) SSTA (Data pending): Defined as sea surface temperature anomalies for the Gulf of Mexico and West Atlantic. The American Meteorological Society states in a February 2003 journal article that "Using a combination of statistical methods and monthly SST anomalies (SSTAs) from one or two ocean regions" there are strong correlations between sea surface temperatures and precipitation during much of the year in the United States."

2) 2009 Hurricane Season (Data pending): Defined as the frequency and track of tropical cyclones in the Atlantic basin. It is hypothesized for discussion that a less active hurricane season combined with a positive ENSO cycle may correlate to increased probability of significant winter storms in the Eastern United States in the following six month period from October to March. Historical data supporting this hypothesis will be provided.

B) Cryosphere (Monitoring specific data sets about the frozen part of the northern hemisphere's polar water system)

1. Arctic sea ice (5.27 mil sq. km as of 9/28): Defined as the total surface area in million square kilometers of sea ice within the Arctic Circle as reported weekly by the National Ice Center.

2. N. Hemispheric snow cover (data pending): Defined as a visual interpretation and data on extent of snow cover across the United States, Canada, Russia, Northern Asia and Europe

C) Atmospheric Data (Monitoring quantitative indices which track variability in atmospheric teleconnective patterns, such as how might air pressure changes over Greenland affect the track of a US East coast storm). Note: Data and info for this section posted later Sunday.

NAO: North Atlantic Oscillation Index (my preferred "local teleconnection" that reveals much about current weather, upcoming pattern changes, storm tracks and cold outbreaks)
PNA: Pacific-North American Index
MJO: Madden-Julian Oscillation Index (wildly intriguing atmospheric hiccup that has been suggested by some is a major factor in the ENSO cycle-- details later.)
QBO: Quasi-Biennial Oscillation Index (interesting pattern relationships between easterly or westerly phase of this index, current solar cycle and latitude variation of North Atlantic winter storms.) Source: 1988 article in the journal Geophysical Research Letters.
now this one's a toughie..
AAM: Axial Angular Momentun of the Atmosphere. (you better take some Tylenol before we go over this.)

D) Solar Cycle (data pending): Defined as the monthly mean, frequency and duration of sun spots as an influential factor in Earth climate)

PART 3: PROJECTED STORM EVENTS for November and December 2009. A prediction calendar to be posted here and in the sidebar links for those interested in tracking both the predictions and the progress of the data. In the spirit of our first annual "Winter Symposium," all appropriate and respectful input on this topic is welcome. All comments will be moderated before being posted to the public.

Mr. Foot
Science Teacher ~ The Crossroads Center
Baltimore County Public Schools

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