A difference of opinion...(4-4-13)

<B>(9:30 pm Thursday April 4th)</B> You may see conflicting forecasts for central New York next week and you can blame a wide division in computer models for that....
The cold and snow of the first few days of April has certainly made us look ahead to any sign of real springtime warmth.  Not just getting temperatures into the 50s, or close to normal for this time of year, but for 60 or even 70 degree weather that would really jump start lawns and trees across the area and send us scrambling to find the shorts. One of our computer models, the GFS, has given us a tantalizing forecast for the middle of next week. Low pressure would track to our west sending a warm front to the north of central New York .  Here is what the GFS was advertising this afternoon for it’s forecast for next Thursday.

While the GFS has looked tempting the last couple of days, we have been looking at our other computer models for consensus as a way to increase our confidence in forecast much above temperatures here in Syracuse. It is just not there.  One way is to look at models like the European.  It has been as emphatic the last few days that after next Monday the front moves south and stays there through Thursday as cool high pressure tries to nose in from Canada. Here is a forecast map for the same period as the GFS above but this time for the European:

Sorry that the scale of the map is much smaller but the takeaway is that the front is much farther south compared to what the GFS is showing. This solution from the European for us here in central New York is more seasonably cool weather.

To give you another way to look at what we are up against, here is some raw model data.  These are forecast temperatures at 850 mb (about 5,000 feet).  This can give us an approximation of the air in the lower atmosphere and potential for our high temperatures.  These temperatures aloft are in celsius:

TimeGFS 850 mbEuropean 850 mb
Monday Eve+4.5 c+3.0 c
Tuesday Eve+8.0 c-4.5 c
Wednesday Eve+13.0 c-4.6 c

These numbers were taken of the Thursday morning runs of both models. You literally have one model (the GFS) saying 70s are a possibility while another model (European) says we are stuck in the 40s to low 50s! Usually when there is that much difference one of the models changes their tune to the opposing model over time but not in this case, so far.  Each model has dug into its position the last two days as if they were playing a game of meteorological model chicken.

In these cases we like to go to each models ensemble forecasts.  This is where meteorologists change the initial conditions slightly and run the models many times over.  In some cases you get a couple dozen ‘solutions.’ Again, as a meteorologist, you are looking for consensus from most or all these ensemble members.  For the last couple of days that has NOT been the case with the GFS and its ensembles. I think I counted only 3 out of 11 GFS ensemble members getting the warmth to us. This lowers the confidences in the main, operational GFS forecast.

So the bottom line is our forecast for the middle of next week is based on the front staying to our SOUTH along with the really warm air.  Could things change?  Sure, but given the data were looking at right now, the odds would favor a solution with temperatures closer to 50 than 70 next week and that is what you see in our 7 day forecast..

Even if the warmth that the GFS is forecasting for next week doesn’t pan out, there is another chance the warmth could try to build back toward us the following week (week of April 15th) but that is talk for another future blog......

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