Dick Faurot's Weather Blog: Guidance Leading Up to Christmas

In yesterday's blog I mentioned that the long range GFS was suggesting the potential for some wintry weather leading up to Christmas. I also mentioned that there may be some internet sites broadcasting a White Christmas for us based on that solution and cautioned against taking that solution as Gospel due to the fact that among other things, more run to run consistency was needed before jumping on that particular bandwagon.

Notice the first map which is the 348 hour forecast from the GFS valid 6 PM Tuesday, Dec. 23 and based on data initialized yesterday at 6 a.m. As mentioned, if this solution were to verify it strongly suggests cold, wet weather for much of our state and accumulating amounts of snow. Now, notice the second map which is the 324 hour forecast valid for the same date and time but from data initialized at 6 AM today. The differences from just 24 hours ago are striking as the more recent solution has backed off considerably in the magnitude and areal coverage of any precipitation as well as how cold it would be. This illustrates what I was referring to yesterday regarding the internal, run to run consistency, or lack thereof, regarding the solutions available at those longer time ranges.

As also mentioned yesterday, flip-flops are not uncommon at those time ranges and we will likely see some additional flip-flops before the models settle into a more consistent solution. Also, it will be several more days before the operational ECMWF solution extends into that time range and if we start seeing consistency not only from run to run but between the different model solutions, then we will have more confidence regarding what to base a forecast on.

That is still two weeks out, so what about the shorter term? Well, as expected clouds have increased this afternoon, overcast skies are expected for the overnight hours, and little or no sunshine is then expected for the rest of this week right on through the weekend and into early next week. This will be primarily a low level stratus deck which could result in some very light drizzle or a light mist from time to time starting tonight and right on through Saturday. Little or no measurable precipitation is expected from this, but that will change Sunday into Monday when a stronger storm system will be moving across the state.

The latest guidance continues to be consistent in bringing widespread showers/storms for that time frame with the activity likely reaching this side of the state during the late afternoon hours of Sunday and then moving on eastward with some wrap-around lighter showers into the morning hours of Monday. Notice the seven-day QPF map which suggests the potential of an inch or so of rain by the end of that period.

The cloud cover will also impact temperatures with lows near 40 to start the day Thursday, well into the 40s to near 50 for Fri and Sat mornings, and likely in the 50s for Sunday morning. Keep in mind, our normal daytime high at this time of year is right around 50. Daytime temperatures will be in the low 50s again Thu, well into the 50s Friday, and 60s for Sat/Sun.

At least the winds will be relatively light with SE winds generally less than 10 mph until the weekend when a stronger S/SE wind is expected for Saturday and even stronger southerly winds for Sunday. Brisk northerly winds on the backside of the storm system will result in much cooler conditions for Mon/Tue of next week. But, notice the 8-14 day outlooks which continue to suggest above normal temperatures and the possibility of some unsettled weather leading up to Christmas.

So, stay tuned and check back for updates.

Dick Faurot