Wednesday, April 20, 2016

Seasonal Forecast

Here's a quick update to show the latest CFSv2 model forecast for next month.  The model ensemble is calibrated with the historical re-forecasts and converted into the probabilities that the climate anomalies will be significantly below-normal, near-normal, or significantly above-normal.  The temperature forecast for May shows continued high probabilities of unusual warmth for most of Alaska, exceeding 90% over the warm water in the Gulf of Alaska and Bristol Bay, and 60-70% in most of the interior except the east.


The forecast for the May through July average is similar, although the probability of warmth is not quite as high in the interior.  There is a surprising area of expected cooler than normal conditions in the Chukchi Sea; this is probably related to the CFSv2 sea ice forecast, which is not known to be particularly reliable.


Interestingly the 3-month forecast for sea-level pressure shows a low pressure anomaly across interior Alaska, and the precipitation forecast hints at above-normal rainfall in the southeastern interior.



The probability forecast for Fairbanks shows a modestly enhanced probability of a wet May-July period, and it seems the model expects this anomaly to show up in July; the probability of significantly above-normal rainfall in July is 48%, compared to 36% for the near-normal category and only 16% for below-normal.




The official CPC forecast will come out tomorrow:

http://www.cpc.ncep.noaa.gov/products/predictions/long_range/

Also, I added the March verification at the end of my post from 2 months ago:

http://ak-wx.blogspot.com.es/2016/02/seasonal-forecast.html

Update: here's the CPC forecast; the most interesting aspect may be the expectation for above-normal precipitation across northern Alaska in May-July.  It's also interesting that the CPC doesn't buy the CFSv2 forecast for an increased chance of wet conditions in southeast Alaska.



3 comments:

  1. I wonder how this forecast relates to the potential for wildfires? It's an annual consideration. Here's a good source of contemporary info:

    http://www.weather.gov/arh/fire

    Gary

    ReplyDelete
    Replies
    1. It appears to be bad news for the short term, and a hint of good news for later in the season. Perhaps like last year the fire season will start off active and fade in July and August.

      Here's the monthly fire potential outlook:

      http://fire.ak.blm.gov/content/weather/outlooks/monthly.pdf

      Delete
  2. Rain in July in the interior would be good. Whether they like it or not, they could use it.

    ReplyDelete