METEOROLOGY 361                                                                                                                                                        Spring, 2007

Exam 1                                                                                                                  

 

 

Directions: This is an Open-notes exam.  Use anything you want, including the Internet but you can’t ask each other questions or contact another student in any way to discuss the exam.  I'm trusting you on that point.  Answer all parts of all 3 questions unless otherwise directed.  If you like, you may create a text or Word file with your answers and e-mail them to me.  The answers are due by 1 p.m. Friday at our next class.

 

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1. This question refers to the situation that was developing on January 5, 2005.  You have the following resources:  The U.S. surface analysis at 12Z on January 4, 2005, the 12Z January 5, 2005 upper air maps as follows: 850 mb map, the 700 mb map, the 500 mb map, the 300 mb map, and the 200 mb map.  You also have a 60 hour 500 mb forecast loop initialized on 12Z January 4, 2005, an 850 mb forecast loop initialized at 00Z on January 4, 2005, the GFS 168 hour MSL forecast initialized 00Z Dec 29, 2004, the GFS 168 hour 300 mb forecast, the GFS 96 hour MSL forecast initialized 00Z January 1, 2005, the GFS 96 hour 300 mb forecast, the Eta (now called NAM) 72 hour MSL forecast initialized 00Z January 2, 2005, and the Eta 24 hour MSL forecast initialized 00Z January 4, 2005.

    a. ( 18%) Based on the information you have, what were the surface weather conditions like at 00Z January 5, 2005 in Denver Colorado, Omaha Nebraska, and St. Louis Missouri?  To see the locations of these cities, click here for a map of NWS offices.  Note that none of the three cities appear on the 12Z Jan 4 surface map.  Discuss the precipitation types, approximate temperature levels, and wind speeds (also approximate).

    b. ( 24%) Assess the potential for a heavy snowstorm for places in Wyoming, Nebraska, and eastern Colorado, based on the information and forecasts given.  You  must also justify your assessment using specific meteorological reasoning based on factors found on the given maps.  This will be written in the form of a weather discussion such as we have done orally in class on Wednesdays.  You must have at least 4 reasons to justify your assessment.

2. For this question you should examine the following cross sections:  one showing only isentropes, one showing isentropes and isotachs, and one showing isentropes, wind flags, and mixing ratio lines.
    a. ( 7%) Considering only the surface, at which station is the atmosphere warmest?  What is that surface temperature?
    b. ( 7%) At which station is the atmosphere coldest at the surface?  What is the surface temperature at the coldest station?
    c. ( 9%) Are there any fronts at the surface?  If so, where are they (use the stations for locations) and identify the kind of front.
    d. ( 15%) You should download a blank Skew-T Log P diagram from this link.  Either print it or use a drawing program to complete this answer.  Draw a sounding of temperature and one of dew point which are consistent with the cross section at GRB.  It doesn't have to be exact, but you must show soundings which fit the behavior of the cross section.  One place you must be more quantitative is the surface temperature which must be within 1°C.  Finally, on your sounding you must show the tropopause (label it TROP).




3. This question refers to an extratropical cyclone which affected the northeastern U.S. in late October, 2006.  You have a surface analysis loop, a 500 mb vorticity initialization from 12Z on October 28, 2006, and a 300 mb map from that same time.
    a. ( 10%) From the surface loop, you will notice that during the morning of October 28, a secondary low developed on the front.  However, it did not intensify and, in fact, the Ohio valley low continued to be the primary storm.even when it got to New York State.  What was different about this storm from the classic nor'easter from December 24, 2002 that we studied in class?
    b. ( 10%) Two forecasts, the 48 hour NAM MSL and the 72 hour NAM MSL both erroneously showed the coastal low to be the main storm.  Considering an inland city such as Pittsburgh, how would the forecast be different with the secondary (coastal) low being  the main storm instead of the Ohio valley low as was actually the case?  Be as specific as you can with how the forecast elements would be changed.