12.310

Assignment 3: Fronts
1. Reading & problems from  Meteorological Manual 

No reading assignment.

2. Weather on the web

Use the PAOC Synoptic Laboratory web to investigate the most recent surface and upper air maps.  In particular pay attention to regions of marked temperature gradients, the so-called fronts.

Boston Weather  

Surface Analysis - Study the latest NWS surface analyses over the U.S.

Station Obs/Surface – inspect MSLP, fronts, and obs

It shows mean sea level pressure (MSLP) and the positions of cold and warm fronts, along with a few station observations.

a) Identify regions of low and high pressure.

b) Locate any significant cold or warm fronts.

c) Are there any fronts in our region?  

Boston Forecast 

NWS Fronts Forecast - Take a look at the NWS fronts forecast over the U.S.

Forecasts/US – click on NWS/surface

These maps show the NWS forecast of surface fronts, MSLP, and precipitation over the continental United States for the next 48 hours.

d) Where are the fronts expected to move during the next 48 hours?

e) Will any fronts move through Boston?  When?  How do you expect the surface wind and temperature to change?

Computer Model Forecasts - Check on the computer model forecasts

Forecasts/US – view the surface forecast maps from two different regional models:

NAM /surface (formerly called the ETA)

GFS /surface (formerly called the AVN)

These maps show surface pressure, 1000-500 mb thickness and precipitation forecast over the continental U.S. for next 48hrs.  Use the thickness field to identify regions of cold and warm air.

What do you expect to happen in the Boston area during the next 48 hours? 

Do you notice any difference between the two models?

Make a forecast for Boston over the next 48 hours.  Consider what will happen to the temperature, pressure, and surface wind.  Will there be any precipitation?

Do not forget to include date and time of when you prepared your forecast.

3.  A case study: the Polar Front on January 10, 2008

In this second part of the assignment we will study the horizontal and vertical structure of the Polar Front, the boundary between the cold polar air and warm equatorial air.

Note: you don't need the web for this part of the Assignment. Use the hand out given in class.

NOTE.  This is what is expected from Assignment III:

Part 1- Reading: No reading.

Part 2 - Current Weather

a.) Answers questions on Surface analysis and Fronts forecast

b.) Paragraph on NAM/GFS Forecast for Boston

Part 3 - Case Study

c.) 500mb map of temperature: mark the position of the polar front.

d.) Vertical section of the polar front - answer questions 1-6.

e.) Compare the observed structure of the Polar Front, as viewed in the above case study, to the "cylinder collapse" experiment, performed in class. For more on the rotating tank experiment see the fronts project in the "Weather in a Tank" labguide.

f.) Answer the thickness equation question.

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