Ramblings of a Graduate Student

Well, as the majority of the blog posts so far have indicated, most of the country is in the midst of an extended cold snap.  Unfortunately, it appears that the cold snap is about to get colder.  Today’s weather graphic is once again taken from the National Weather Service (NWS).  It is an image containing all valid NWS watches, warnings, and advisories that are currently in effect.   A good portion of the eastern two-thirds of the country has some sort of winter weather product in effect.  These range from a very small Blizzard Warning in eastern Montana (bright red) to a winter storm warning for much of western Iowa to a Hard Freeze Warning for a good portion of the southeast to a Freeze Warning throughout much of the Florida peninsula.

The good news is that the NWP models meteorologists use to help predict the weather are suggesting that Old Man Winter should lessen his icy grip on the US sometime next week.  We certainly won’t see summer like weather, but places that aren’t used to spending days below freezing should return to more normal winter temperatures.  Remember, a lot can happen between now and then, and the forecasts may change, but it should offer hope to those who are tired of the cold.

(Image courtesy of the National Weather Service.)

I hope you enjoyed the deviation from the cold air with yesterday’s post on severe thunderstorms and tornadoes.  Today, we’re back to highlighting the impending cold air outbreak.  Below is a graphic created from the Global Forecast System (GFS) numerical weather prediction model (NWP).  It is taken from the 12UTC (6 AM CST) run¹ from 4 January 2010 and is valid² at 12 UTC (6 AM CST) Friday, 8 January 2010.  In other words, this is a good approximation as to what the NWP model is predicting for overnight low temperatures Thursday night/Friday morning (for locations in central time zone).  The temperatures contoured are predicted 10 meters above ground level temperatures, which means locations where the winds are calm and the sky is clear, the surface temperature will most likely be even colder.

A couple of things to note about this forecast.

1. The temperatures are in degrees Celsius.  For those who don’t like math³, -30C = -22F ; -20C = -4F ;
   -10C = 14F ; 0C = 32F ; 10C = 50F ; 20C = 68F ; 30F = 86F.
2. The green color fills are the liquid equivalents for any precipitation that has fallen during the previous 6 hours⁴.
3. Almost everywhere is below 0C (32F).  The only places where this isn’t the case is the west coast, extreme southern Texas, and the peninsula of Florida (which will most likely experience below freezing temperatures the following night).

(Image Courtesy of the NWS National Centers for Environmental Prediction Central Operations)

Deviating from the cold theme of the past two days (mainly because I just got back from a walk and am freezing…), today’s map deals with severe thunderstorms and tornadoes.

Every year the National Weather Service’s (NWS) Storm Prediction Center (SPC) issues approximately 850 severe thunderstorm and tornado watches combined.  Greg Carbin, the Warning Coordination Meteorologist (WCM) at the SPC, put together a graphic that contains the number of watches issued per county during 2009 (valid through October).

A couple of things stand out about the geographic distribution of this year’s convective watches.

1. Central Oklahoma had the most watches (~35) of anywhere in the United States.
2. There are few watches issued west of the Continental Divide.
3. East of the Continental Divide, only four areas did not record a single convective watch: far western Texas (El Paso area), far southern Texas (Brownsville area), east central Wisconsin (Green Bay area), and eastern Maine (Portland and Jonesport areas).
4. There is a relative minimum in watches from southwest to north central Kansas – right in the middle of theVORTEX II domain.
5. There is a relative maximum in watches from northeast Colorado into eastern Wyoming and western Nebraska – several of which were issued during VORTEX II.  (VORTEX II’s only significant tornado intercept occurred nearLa Grange, Wyoming, near the border of Wyoming and Nebraska.)
6. The lack of repeated land-falling tropical systems resulted in no coastal areas having a pronounced maximum.

(Image courtesy of the NWS SPC.)

Since 365 blogs are all the rage I thought I’d go ahead and try one.  The catch?  Instead of posting a photograph a day I’ll be posting a weather map a day and trying to give a quick overview of it.  We’ll see how long this lasts…

Day 1 is a map generated by the National Operational Hydrologic Remote Sensing Center (part of the National Weather Service) of snow cover for the continental United States (known as the National Snow Analysis).  As you can see a majority of the CONUS is covered with snow.  In fact, checking this map on Christmas Day revealed that approximately 2/3rds of the CONUS had a White Christmas (defined to be 1″ of snow on the ground).  Today’s map only differs slightly from the snow cover map on Christmas Day – mainly across northwest Texas (where melting has occurred) and across central Missouri eastward through southern Indiana (where recent snowfall has resulted in minor accumulations).

A major cold surge forecast to grip areas east of the Rocky Mountains next week.  Couple this with several minor upper-level lows forecast to move through the eastern US, the snow area should expand southward next week.

(Click on the image to view it in its native resolution.)

For the past two years I have *theoretically* been working on a PhD dissertation in the realm of climate change science – namely, investigating the potential affects of anthropogenic climate change on severe thunderstorm environments.  My advisers have been world-renowned scientists in either climate change or severe thunderstorm environments.  The downside to all of this is that one of my advisers now lives in Australia, and the other is a scientist at the National Severe Storms Laboratory.  Both of these scientists are incredibly busy and it makes things difficult for a graduate student needing mentorship and guidance.

All of that is background information to justify my recent decision to change my dissertation topic.  I’m leaving the climate change sciences (for the time being) and coming back to my true love…severe thunderstorms and tornadoes.  I don’t have a specific topic at the moment, but I do have a general area I’d like to do research – southeast US, cool-season severe weather events.  To the non-meteorologists, this might seem a bit boring, but it is actually one of the more fascinating, and incredibly difficult / complex problems remaining in severe thunderstorm and tornado forecasting.  A disproportionate number of tornado fatalities occur in the southeast United States, most occurring in what is typically referred to as the “cool-season” (roughly late October through March). (The 5 February 2008 Super Tuesday tornado outbreak is a perfect example of a southeast US cool-season tornado outbreak – 55 fatalities in 4 states).  There is a lot of speculation as to why there is such a high number of fatalities (socio-economic reasons, nighttime tornadoes, etc), but none of this speculation helps with improving forecast skill in these areas, and almost certainly doesn’t matter to the residents affected by these events.

My current plan is to spend the next month or two identifying exactly what are some of the problems in forecasting these events, and then write a short 10-15 page summary of my findings and what I plan to do to address the scientific questions I raise.  After this, I’ll present a seminar to the National Weather Center detailing my findings, and hopefully announce what I plan to specifically address for my PhD.  Thus, over the next few weeks I’ll talk to my friends at the Storm Prediction Center and seek the source of some of their frustrations regarding these cool-season events, read National Weather Service Service Assessment reports on known events, and read a lot of journal articles.

I can’t wait to begin…