Questionable Weekend Weather

There are a lot of questions about the weather this weekend.  First, will it be a washout?  Second, will we see the sun at all?  What’s up with Matthew?!?

1.  No.  Many of us inside 495 woke up to rain Saturday morning and the National Weather Service even issued a Flood Advisory at one point for the greater Boston area.  But that won’t last all day.  There will be some breaks in the rain.  That will be followed by another period of rain.  So it will be off/on Saturday.  If you want to get outdoors this weekend, there will be some brief periods of dry weather on Saturday.  There will be longer periods of dry weather on Sunday.  So, Sunday is probably the better of the two weekend days.

2.  No.  While there won’t be much rain west of 495 on Saturday, or much rain anywhere on Sunday, there won’t be any sunshine either.  It remains cloudy, dreary and cool all weekend.  I’m sorry.  But at least we are putting a small dent in the drought…Boston has received over half an inch of rain already this Saturday morning.

3.  Yeah, wow!  Friday evening Matthew became the first cat 5 hurricane since Felix in 2007.  To quote the National Hurricane Center (NHC) it strengthened “at a remarkable rate” on Friday — 55 knots of wind and 44 millibars of pressure in 24 hours!!  To put that in perspective, meteorologists refer to a storm that strengthens 24 millibars in 24 hours as a “bomb.”  That brings up another question…where is it going?!?

There is pretty good agreement among all of our computer model forecasts that Matthew will pass over the eastern part of Cuba on Tuesday, then over the Bahamas on Wednesday and Thursday.  After that, there is very little agreement.  The European computer model curves Matthew well to the east and keeps it safely out in the Atlantic.  The GFS computer model (from the United States) has a more westward track and brings Matthew right over us.  Most of the other models are somewhere in between.  That brings up yet another question…who’s right?!?

Well the NHC actually keeps track of these things.  Last year, it was an interpolated, adjusted version of the European model (EMXI in the chart below) that did the best.  In fact, in the long range it was better than the official, human forecast from the NHC (OFCL in the chart below).   That was followed closely by an interpolated, adjusted version of the GFS model (GFSI in the chart below).  However, that was last year and using last year’s stats to predict what will happen this year works about as well with weather as it does with fantasy football.

NHC Verification Stats

The official forecast from the NHC only goes out to 5 days.  *IF* Matthew were to impact our weather at all, it wouldn’t be until sometime next weekend.  So for now we have to rely on those long range computer models.