Baltimore is located near the northern edge of the Chesapeake Bay in north-central Maryland. It is a major port city because of its location on the bay but is separated from the Atlantic Ocean by the Delmarva Peninsula which is very flat so doesn't act to impede air masses coming off the Atlantic given a strong enough easterly wind. The city varies in elevation from sea level in the inner harbor to about 150 m in the northwest suburbs, with the foothills of the Appalachian Mountains a good 80 km away to the northwest of the city. Time to stalk the airport!
KBWI is located southwest of the city center a little less than 10 km from the Chesapeake Bay. KBWI's WMO ID is 72406. Be sure to check in with the local NWS WFO which is the Sterling, VA Office. A convenient quality of KBWI is that it is located in our timezone (EST) which minimizes conversions for us!
Large-scale Pattern:
The forecast upper-level pattern according to the GFS for the start of our first week of forecasting shows the growing amplitude of the longwave upper-level trough throughout the entire week with a few embedded shortwaves that could force some disturbances, especially the coastal development expected for Wednesday. The forecast temperatures should be well below normal given the cold air mass that is associated with that deep trough and has been highlighted by CPC's 6-10 day outlook. The outlook also calls for above average precipitation for around BWI and the entire East Coast because of the location of the trough just upstream of a semi-permanent baroclinic zone (continental air vs. Gulf Stream) that is perfect for activating the Atlantic storm track like we've seen plenty of evidence of this winter. To summarize, the large-scale pattern looks pretty good for cold and precipitation as I think we'll see as we start forecasting.
Tips/Comments for Forecasting in General:
- Check out the current weather first via satellite, radar, surface observations, METAR, etc. You have to understand the present before you can look to the future.
- Get a feel for general pattern from NAM, GFS, etc. (available from here and here, for example). Identify the general pattern of low and high surface pressure systems and their progression, temperature advection at 850 mb, moisture at 700 mb, vorticity at 500 mb and the general jet structure at 300 mb. Make sure you are focusing your attention on Baltimore.
- Look at forecast model soundings for the period for KBWI.
- How are the models evolving in time? Check out d(model)/dt plots like this one that focuses on the GFS.
- Ensembles are your friend. Here's a cool page for some spaghetti from the GEFS. Here's a winter-specific SREF page just for fun.
- Compare your idea for values with MOS (model output statistics). Keep in mind these are instantaneous output values and you can always have values above/below that between output times.
- Read the Sterling, VA WFO forecast discussion for info on BWI. These are the experts for that location, after all!
- Other universities have great WxChallenge-specific pages:
Tips/Comments for Forecasting for High/Low temperature (Fahrenheit):
- Recall such basics as nighttime radiative cooling and daytime solar radiative heating, both of which are affected by cloud cover and fog. Should there be snow-cover then temperatures can potentially be a bit colder due to snow's reflective properties and low heat capacity.
- Frontal passages can affect your temperature forecast. Pay attention to the forecast timing of such frontal passages especially right at the start of our first week of forecasting for KBWI!
- Given quiet synoptic players, the evening dew point can act as a rough guess for the nighttime low (some forecasters use this as a first guess when they think the model output statistics (MOS) is bonkers). Therefore the wind direction may be a good indicator of humidity which may affect the nighttime temperatures.
- An easterly wind direction should make BWI temperatures warmer given the proximity to the coast.
Tips/Comments for Forecasting Wind Speed (knots):
- NWS outputs wind speed in mph so if you are comparing your forecast value to theirs keep that in mind. Otherwise the models output wind speed (WSP) in knots.
- Look through METAR or surface obs for wind direction and temperature changes.
Tips/Comments for Forecasting Precipitation (inches):
- Take a look at some higher-resolution models (e.g. WRF, hi-res NAM) or compare a whole bunch at once using a meteogram (ISU)
- This forecast city is actually in our model domains for the SBU-WRF that is run twice daily. We don't have any time-series or soundings for BWI because we are narcissistic and centralizing it on Long Island but the cross section from B-B' should capture very near to BWI at the southwestern endpoint.
- What does the WPC show?
- Take a look at some GFS model-derived standardized anomalies of precipitable water (PWAT) to get a handle on any significant movement of the forecast of dry air or very moist air.
- Take a look at some ensemble data (e.g. SREF (South Central option) or for a zoomed-in national look try here. And for a winter-weather specific SREF page then check this out.)
- Most products you will be looking at will output the QPF in inches already so no conversion is necessary. Recall that we are forecasting for the liquid precipitation so if the forecast calls for snow, make sure you aren't forecasting 4 inches-- use the liquid equivalent.
Be sure to check out a previous post found here for a long list of great resources that you should check out! Most of them are also found on Dr. Colle's Coastal Meteorology and Atmospheric Prediction (COMAP) group's website. Please feel free to comment below with any cool sites or tools that you've discovered from your experience!
While you peruse the atmospheric data, be sure to play the Star Spangled Banner which was written in Baltimore by Francis Scott Key (see video below). It should be cool forecasting for BWI for the next couple weeks (pun intended)! Brrrr, best of luck and go Team SBU!!!
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