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Spring Fever Spreading

Will Spring be on time for your region? Join the Conversation >> Long Range Spring Outlook

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About this blog

Where I will occasionally post outlooks, recaps, and extended thoughts so as not to clog up a main storm thread. 

Entries in this blog

 

Winter's Opening Salvo

Forecasting / General Post Winter's Opening Salvo November 15 2018 - 0200z    I have my work schedule arranged in such a way that I enjoy a few consecutive days off in the middle of the week. It gives me a chance to "catch up", physically and emotionally, as well as providing a block of time to work on writing and other such projects. There is a pizza place that I frequent on these off days; frequent a little too much, if my rough calculations about yearly spending there are anything to go by. What can I say; they make really good pizza. I left around 15z today to get lunch, and noticed that we finally seem to have turned the corner from one season to the other. There is a solid chill in the air, stemming from a cold air mass originating deep in arctic Canada, and a classic winter wind that I can still hear from time to time as I write this. Perhaps nothing signifies our concluding transition, however, as much as the start of the first significant region-wide wintry event drawing to less than a day away.    This is a true "mixed bag" event, that is, one that will, somewhere, drop every type of wintry precipitation. Many storms have unresolved uncertainties even within the H+24 to H+36 range; the classic question in so many winter nor'easters is the exact location and orientation of the "deformation band", which often yields the highest local snow totals of the storm. For this event, however, the most critical remaining uncertainties, in my opinion, pertain to local temperature profiles, rather than QPF maxima and minima. To explain, allow me to first break down how these temperature profiles relate to precipitation type ("p-type"), and how local microclimates can have major effects on said p-types. I will then provide a brief summary of my forecast thoughts for the storm, and conclude with a safety tip or two. Shall we begin?     The most effective way for meteorologists to look at atmospheric conditions as a function of altitude are through the use of atmospheric soundings. These are launched by the National Weather Service several times a day, with exact frequency depending on regional and/or special requirements (for example, special soundings may be launched prior to a severe weather event, or to gain data for model input in high-consequence situations such as an impending hurricane landfall). Soundings usually consist of a radiosonde delivered via a weather balloon; rockets are the most common alternative. NWS sounding data can be obtained on the Storm Prediction Center website, the NCAR, or from local NWS Weather Forecast Office pages. A typical sounding (in this case, the 12z or 7am sounding from Albany, NY) may look something like this:    This is a LOT of data. The bottom boxes, as well as the hodograph (wind strength and direction relative to altitude) and surrounding charts are most important for protection of severe weather, and as such, will be disregarded for this post. What I want to focus on here, out of all that, is the red line on the plot seen on the top left of the data display. The chart itself is called a Skew-T Log-P diagram; that is, the temperature lines are skewed at an angle, and the pressure lines are represented in logarithmic format. For more reading, you can access some helpful information here, here, and here. That line is a visual representation of the air temperature at different altitudes; the former measured in °C, and the latter in hPa/mb (a note of conversion: 1 hectopascal, or hPa, is equivalent to 1 millibar, or mb). Let's take a closer look, shall we?    Remember that the Skew in Skew-T Log-P denotes the "skewing" of temperature lines off to an angle. The pair of straight blue dotted lines above highlight 10°C and 0°C from left to right. The green line, for reference, measures the dewpoint. Altitude, as I mentioned above, is measured in terms of atmospheric pressure; 1000hPa roughly equates to the surface (in low-lying areas; in higher elevations, the "surface" pressure may be significantly lower). 850hPa is about 5,000 feet, and 700hPa is approximately 10,000 feet. In terms of the temperature profiles I am about to discuss, we are going to focus on the 700hPa-1000hPa range, which is the most important in determining p-types for a specific location. One should note that the exact "true" altitude of a certain hPa line changes in response to temperature; the higher the temperature, the higher the altitude, as illustrated in this graphic.     So, I promised a discussion about temperature profiles. Specifically, how different profiles affect p-types, and how microclimates factor into that affectation. Nearly all precipitation occurring during the colder months of the year starts out as snow, high above the earth where it forms. How it lands on the ground, however, is a factor of two different temperatures: air and ground. We will start with the former. Imagine a single snowflake falling through the atmosphere. As it descends, the temperature of each layer of air it passes through will determine the end p-type of the molecule. If the entire air column is below freezing, the snowflake will stay a snowflake; likewise, if the entire column is above freezing, the snowflake will melt and land as plain rain. Where things get a bit complicated are when there is a "warm nose" somewhere in the lower to mid atmosphere (commonly between 700 and 900 hPa). When this happens, the snowflake will melt and refreeze. If the warm air intrusion is relatively shallow, with a deeper layer of cold below, the molecule will fall as sleet. If the warm layer is deeper, with less cold air available near the surface, the molecule will fall as freezing rain. The chart below is a visual representation of these different temperature profiles.    Tropical Tidbits and Pivotal WX both have point-and-click forecast soundings for several models; you can also plug in an airport identifier (such as KJFK) in the viewer window to pull up a forecast sounding for that location. I encourage all of you to play around with these viewers. Compare them for your location from model to model, and draw your own conclusions.    In regards to rain versus freezing rain, ground temperature also comes into play. Rain falling onto a -5°C surface will freeze; rain falling onto a 5°C surface will not. In that regard, even if most of the layer is above freezing, a cold surface level with subfreezing ground temperatures can lead to "ice on contact". Microclimates come into play here; small, yet crucial, variations in local temperatures coinciding with elevation, local wind flow, bodies of water, etc. Different types of soil will warm and cool at different rates. The water table plays into these things. These minute variations in ground and surface air temperatures can lead to different p-types falling over very small distances. Such factors are important to consider when forecasting a storm like this, where the temperature profile is proved to be variable during the course of the storm, and outcomes may be influenced by rather small changes in temperature. Typically, each microclimate is best understood by those who live nearby. Think to yourselves; what is that one place in town that always gets an extra inch of snow?     Now, I said I'd make some predictions, and I suppose I should live up to that. Below are the forecast snow accumulation maps from the 18z 12km NAM, 3km NAM, RDPS (Canadian short range mesoscale model), and the 00z HRRR (through 8z Friday, some areas will see more after that time). These show ratios of 10:1 (that is, 10" of snow for every 1" of QPF), and exclude sleet and freezing rain.         Now, here are my thoughts (north of the black dashed line has the best chance to stay all snow):      What, you wanted more? I will leave brief word on safety to conclude this message. Drive carefully, especially in areas with microclimate variations. Rain can turn to freezing rain when you drive up a hill, and road conditions can meteorite very quickly. Plan for extra travel time. Power outages may be more of a threat than with many comparable storms due to the saturated nature of the ground. Might not take much on a tree to knock it over.     Thank you for reading. Pass it on if you wish.  TDAT   Image Sources #1, 2 - Storm Prediction Center #3 - National Weather Service #4 - Wikipedia #5, 6, 7, 8, - Pivotal Weather #9 - Base Map from Free World Maps / Google Image Search

TheDayAfterTommorow

TheDayAfterTommorow

 

Seasonal Adjustment

General Post Seasonal Adjustment October 26, 2018 - 0930z      I love the start of winter. I may overuse the word, a consequence of my obsession with descriptive writing, but there is something very ambient about watching the world change from summer to winter. Since I was much, much younger, from my first days of meteorological infatuation, I have loved watching the first signs of the cold season take hold in the world around me. As I sit here in the parking lot, contained in the warmth of my vehicle, I can see so many of them around me. Millbrook received her first frost tonight, as did Poughkeepsie; the more northern reaches of the county saw a light frost the prior morning (I had picked up some overtime and was somewhat surprised to see glaze on my windshield). The thermometer on the vehicle reads 34º right now, a reading I am sure is skewed by the heat given off by the engine.       Across the street, a column of thick vapor rises from a chimney; one of many in this town, I am sure. When standing outside, it is easy to see my breath condensing in front of me. The closest I will ever get to being a dragon, I suppose. Millbrook is quite beautiful at night. The 2010 census proposes a population of just over 1,400 people; a very small fraction in a county that contains nearly a quarter million. The town is motionless in the dark; thru traffic provided by former State Route 44A that bisects the area. It's quite peaceful, and the perfect landscape to inspire some writing such as this.      These inter-seasonal changes aren't just seen in the landscape. We can observe them in the people that surround us as well. You know what I mean. First come the long-sleeved tee-shirts, finally wearable after the scorching highs of July and August; highs that persisted well into September this time around. The shirts eventually thicken into sweaters, and the sweaters into jackets; joined sometime around now by scarves and gloves. It's like a human time-lapse. There are plenty of jokes floating around about New Yorkers and winter, but I will say this; the adaptation from eighty degrees to twenty happens without a second thought. We don our heavier clothing, assume a rather grumpy demeanor, and prepare for the months of cold, snow, and ice that lie ahead.      I've always loved the transition, the quiet excitement that brews ahead of the beauty of snow. Yes, storms may be an inconvenience, but they are also astonishingly pretty; few sights compare to an unmarred blanket of snow. For some of us, members of the meteorological hobby and/or career, the prospect of many nights of tracking and camaraderie also draw near. Few things can bring hundreds of weather nerds together like a good, old-fashioned nor'easter. Even now, the words bring fond memories to my mind. December 26, 2010. October 29, 2011. February 8, 2013. March 14, 2017. March 2, 2018. There are plenty more, and there are more to come.      This was another rambly post, now that I think about it. Yet against all the chaos we see in the world around us, and in our lives, the prospect of winter is something constant. There will be cold mornings. There will be mild spells. There will be phased storms, and missed storms; moments of frustration and of satisfaction. This winter will be different from others before it, and yet it will be the same as them. I guess it gives me a measure of comfort.     Here's to many days of tracking ahead of us.  TDAT      

TheDayAfterTommorow

TheDayAfterTommorow

 

My Background

General Post My Background September 08, 2018 - 0300z      I would like to begin this blog by sharing a few things about myself, as I am sure this forum will soon see an increasing number of members who were never part of the AccuWX boards, or who were, and don't remember me. It's alright, I won't take it too personally. I feel like before you go on to read any weather-related thoughts I may have, you should have an understanding of my credentials, training, and background; that will allow you to place a personal value to how relevant you think my ramblings are. Judge for yourself!      For a long time, my goal in life was to become a career meteorologist. My fascination with weather, specifically extreme weather, began at a very young age, as I am sure many of yours did as well. I joined the AccuWX forums in 2010, at the age of twelve, little more than a hobbyist. During my eight years on those boards, I had the pleasure of learning from a wide range of fellow members who ranged from hardcore nerds (you know who you are), to several professional meteorologists. When I say I learned a lot, I don't mean to speak to my benefit, but to theirs; especially for bearing with me during my true whippersnapper years. I ran a weather blog for a few years, I believe 2014-2015, although I can't say for sure. The blog reached something like 26,000 views, and at the time, was my proudest accomplishment.       During High School, my career plans became somewhat muddled (along with every other High Schooler that has ever lived), including contemplations of joining the military. That sort of panned out, as I did end up joining up with the US Air Force Auxiliary in early 2015, an organization that, among other tasks, focuses on Wilderness Search and Rescue. I attended the National Emergency Services Academy that summer and came out with the highest GSAR (Ground SAR) rating I could attain at the time, and found myself in love with emergency operations enough to join the local Fire Department that winter, and enroll in an EMT class roughly a year and a half later.     That brings me to today, where I hold New York State certifications as a Firefighter I and Emergency Medical Technician (as well as a Connecticut EMT rating required for my job). I am currently in the final stages of an Advanced EMT class, and plan to go to Paramedic school upstate next year. Although meteorology might no longer be my given choice of career, it is still a fascination and obsession, especially considering the inevitable intersection between my job and the weather. Boy, that got rambly. On to the good stuff!

TheDayAfterTommorow

TheDayAfterTommorow

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