City #4: Astoria, OR (KAST)

*** The WxChallenge changed the city from North Bend to Astoria. We are forecasting for Astoria (KAST) not North Bend (KOTH). ***

Hi guys! Today not only do we resume classes after missing a week due to Sandy but we begin forecasting for a new city for the WxChallenge. Thank you all for your cooperation in submitting forecasts despite region-wide power losses. Our team score didn't suffer... too... badly... *sigh* If you are still without power like I am, please do your best to come to campus and use the Metlab computers or your personal laptop to forecast for Astoria. Selecting "Guidance" for multiple days results in 5 error points for each additional day it is used (you get one freebie) so I'd rather not have us accrue error points again.

We will be forecasting for Astoria, OR today through November 15th. Forecasts are still due by 00 UTC but since we've changed the clocks forecasts are now due by 7:00 PM local time! We are still forecasting for the 24-h period of 06-06 UTC for Astoria which is 10 PM - 10 PM local or PST if you are looking at forecasts from the NWS Portland Office for Astoria Regional Airport.

Astoria is found in northwest Oregon and is situated right on Youngs Bay which is off of the Columbia River that empties into the Pacific Ocean. So needless say this is a marine environment. And during this time of year... it's likely going to be wet.

Taking a moment to stalk the airport where the ASOS station (Station ID= 72791) is, we can see that it is located right on the water. In addition to the marine environment, there is significant topography in the region like Mt. St. Helens that is ~120 km due east and some coastal mountains to the south-southeast and northeast.




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Just to briefly mention what climate normals are, for this time of year it's usually pretty gray (yes that's a climate parameter) with a small diurnal temperature range with highs in the mid-to-upper 50's and lows in the mid-40s. Usually during this time of year, the region starts getting slammed with pacific extratropical cyclones. Let's see how things shape up for our forecasts.

Large-scale Pattern:

A look at forecast 500-hPa heights according to the GFS shows that a trough is expected to "slam into" and "dig deeper" (I prefer to say it with flair instead of "progress into the region" and "increase in amplitude") this week. That should bring a larger chance of rain and slightly cooler temperatures to Astoria.

What to watch out for (IMO):

• Upper-level lows coming from the Pacific and Gulf of Alaska.
• Fog is seen to develop overnight if the winds are light enough and no significant synoptic system is affecting the area so early evening dew points right before you submit your forecast may be a good guidance for a nighttime low.

 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 Astoria. Beware of cold fronts during this time of year.
• Look at forecast model soundings for the period for KAST.
• 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 Portland, OR WFO forecast discussion for KAST.

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.
• Frontal passages can affect your temperature forecast. Pay attention to the forecast timing of such frontal passages, especially cold fronts for Astoria.

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. For example, westerlies may bring warmer oceanic air inland to Astoria.

Tips/Comments for Forecasting Precipitation (inches):

• Take a look at some higher-resolution models (e.g. WRF)
• What does the HPC show?
• Take a look at some ensemble data (e.g. SREF or for a zoomed-in national look because the PSU e-wall doesn't have a zoomed-in Pacific Northwest option, try here.)
• Most products you will be looking at will output the QPF in inches already so no conversion is necessary.

Alright guys- grab your solar lamps and cups of hot tea (or Starbucks since we are sort of close to Seattle) and get to forecasting! Hopefully we can all forecast fully for Astoria without some devastating storm knocking out our power... *cough* *cough* Nor'easter *cough* *cough* If you have any questions or want to discuss anything, feel free to comment on this post. Best of luck forecasting! Go SBU!