Anytime we write about winter weather issues here, it stirs up more passion than the Alabama-Auburn football rivalry (well, maybe not quite that much!). Nothing has changed in our thinking about the pattern in coming weeks… it can all be summed up with these two statements:
*The weather will be amazingly cold over much of the nation east of the Rockies, on an average basis, during the next two to three weeks. For some places, as cold as it has been in many years. Perhaps going back to the mid 1980s.
*On the southern periphery of the Arctic air, there will be multiple storm systems that form during the same time frame, and will bring the risk of snow or ice to parts of the southern U.S.
Beyond that, there is no way to resolve details beyond a few days. I have written this all along, and maintain that position this morning. I have no idea why that brings out the “hate mail” guys, but we maintain open comments here, and welcome them as long as they don’t get into personal attacks and use profanity. We also don’t allow abuse (typing the same words over again dozens of times and stuff like that. My nine year old is more mature than some of these guys). I don’t think too many of these folks have a background in atmospheric science, however, so use their comments with caution.
The great thing about the blog is that you can go back and read everything we have written in months past. Right and wrong. It is all there for the world to see.
I should also note many prefer other sources (Weather Channel, etc) that forecast climatology in the long range (50s and 30s this time of the year). Most all of those other sources had a high today in the mid 50s five days ago. Today’s afternoon high will be in the mid 30s, a 20 degree error for them. The same “hate mail” people were all over that one too five days ago; saying we were foolish for forecasting such a cold air intrusion. I think you should hold off the hate mail and nasty comments until after the forecast period. Just an opinion.
MOVING ON: See the new ECMWF at 500 mb (18,000 to 20,000 feet), valid this Friday evening (September 2);
This model has an excellent understand of the pattern, with the SOI going negative along with a negative AO. That is bone chilling cold for much of the central U.S.
Many NWS offices are understanding this. From Norman, OK:
“WE ALSO HAVE LOWERED TEMPS THU AND BEYOND TO WELL BELOW AVAILABLE MOS GUIDANCE… WITH READINGS EXPECTED THAT MAY RIVAL OR EXCEED THE OUTBREAK OF MID JANUARY WHEN MANY AREAS STAYED BELOW FREEZING FOR UP TO A WEEK. IF THERE WERE A BIG MASS OF ARCTIC AIR UP THERE RIGHT NOW… READY AND WAITING TO BREAK LOOSE… WE WOULD LOWER THE TEMPS EVEN MORE. STILL MAY NEED TO DO THAT IN LATER FORECASTS.”
From Huntsville:
“ALTHOUGH THE REX BLOCK OVER THE WEST COAST WILL BREAK DOWN IN THE SHORT TERM…THE PATTERN JUST RE-BLOCKS AND WE STAY IN THE LONGWAVE TROUGH THROUGH THE PERIOD. 00Z ENSEMBLE MOS IS IN THE OFFICE NOW AND IT SHOULD BE NOTED THAT (EXCEPT FOR TOMORROW NIGHT) EVERY SINGLE MAX AND MIN TEMPERATURE IS LOWER ON THE ENSEMBLE MEAN THAN THE 00Z MEXMOS. IN THESE SITUATIONS…THE MODEL HAS A GREAT HANDLE ON THE OVERALL PATTERN BUT IS ALMOST INCAPABLE OF HANDLING DETAIL IN THE EXTENDED. ACCORDINGLY…I HAVE UNDERCUT THE MEX GUIDANCE IN ALMOST EVERY PERIOD THROUGH THE ENTIRE FORECAST…SIGNIFICANTLY IN DAYS 5 THROUGH 8.”
As written here for the last five days, there will be a storm system in the Feb 1-2 time frame that will impact the southern U.S. I am still not ready to define a rain-snow line for this; with the horrible model thermal scheme it is almost impossible to do right now. I will give it a first shot tomorrow morning. There will be other storm systems, and the cold air will be continue to be reinforced, with the air coming over an increasing snow pack over mid-America.
But once again, I have no way of telling you now who will get snow from this first system (and, as you know, I take them one at a time… there is no other way).
Headed out for church with the family… stay warm!
