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Holy crap forecast changed again. Now forecast to be a high of just 39 next Tuesday.
Isn't it fun to watch the changes? It's also funny to watch NWS and other outlets play catch up with the models. It's like they don't believe them too quick. lol. I don't blame them past 4 days but I rarely see forecasts start out cold then adjust warm. Seems like its the opposite.
Quote:
Originally Posted by sedimenjerry
For reference, KPDK averages 7 days a year with a high below 40. It's not common. 2018-2019 winter had just one such day and that was in Dec. The avg number of <40 days in December is showing as 1, but the median is 0. Most Decembers don't have any. So to possibly have one Dec 1 is pretty crazy. (One day earlier on Nov 30th would be remarkable. Since 98, KPDK has only recorded one sub 40 high in Nov in 2000 and 2014).
Forecast low of 25 next Wed morning isn't too common either, but we see lows of 25 and below 14 nights a year. Avg of 3 in Dec, but median of 1.
Interesting! Looking at PDK (records only since 1998) The earliest High below 40°F was November 18, 2000 & November 18, 2014. Just twice before December 4th. Atlanta has had many but mostly pre 1970
Quote:
Originally Posted by BullochResident
Tuesday will be the interesting day. Could be the first seasonal sub 50 F high for my area. Sunny skies too.
Big storm over your area (assuming SC) Monday which will stay over land coming north over PA and will bring us rains here and snowstorm for Midwest. The cold behind it will be interesting to watch.
Snow for the smokies?
Quote:
Originally Posted by FrozenI69
I just don’t understand how this could happen without a cutoff low. What else causes Upstate NY to be warm, but points in the Deep South just below to be cold. .
A cut off low would definitely do that but not widespread below normal like shown on map. When New England is above normal and it's because of blocking in the Atlantic, the South will see these cold dips.
Looking at the 500mb maps looks like a large area that gets "trapped" while there is positive heights to the north of it. Reading the discussion.....
"Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EST Wed November 25 2020
Enhanced probabilities for near to above normal temperatures are favored across most of the western and northern CONUS, under predicted ridging and associated with positive 500-hPa height anomalies.Below normal temperatures are likely across much of the southeastern CONUS, in association with the trough over the eastern CONUS. Below normal temperatures are favored over western Mainland Alaska and the Aleutians, while near to above normal temperatures are more likely across eastern Mainland Alaska and the Alaska Panhandle, consistent with the GEFS and ECMWF Calibrated Reforecast tools."
This map is for one day but you can see why the 6-10 "average" is showing above normal probabilitys in the north and below in the south.
Also factor in clouds/rain for the south which will hold back daytime temps!
Looks like today may be our last high above 50 for a while. High today is 56f but drops into 40's for highs and even 30's some days, lows going to to low 20's and some upper teens. Fall weather has really been great this year, it has been mild and has very gradually gotten colder. Now it will start feeling more "winter" like which is right on time for this area of northern AR.
Isn't it fun to watch the changes? It's also funny to watch NWS and other outlets play catch up with the models. It's like they don't believe them too quick. lol. I don't blame them past 4 days but I rarely see forecasts start out cold then adjust warm. Seems like its the opposite.
Interesting! Looking at PDK (records only since 1998) The earliest High below 40°F was November 18, 2000 & November 18, 2014. Just twice before December 4th. Atlanta has had many but mostly pre 1970
Speaking of, Tuesday's high has gone up slightly to 42. Low of 25. It's still early but I feel pretty confident we'll be 42 +/- 3 degrees.
Yea I use KPDK cause for one thing, it's closer to where I actually live NE of downtown (KATL is SW of downtown). And records date back to March 1998. So not a full 30 year data set but good enough for me. And I was 5, almost 6 back then so it matches pretty well with my idea of the weather in Atlanta since it coincides nearly perfectly with my memories.
The earliest "cold" day I can remember was actually when I was visiting for a wedding on Halloween 3 years ago. The high on October 29th was just 41. I couldn't ever remember an October day so cold. Sure enough, I was right. It smashed the record by 9 degrees. KPDK had never had a high temp lower than 50 in October and that day we topped out at 41. Even November has only had 3 days with a high below 41.
Isn't it fun to watch the changes? It's also funny to watch NWS and other outlets play catch up with the models. It's like they don't believe them too quick. lol. I don't blame them past 4 days but I rarely see forecasts start out cold then adjust warm. Seems like its the opposite.
Interesting! Looking at PDK (records only since 1998) The earliest High below 40°F was November 18, 2000 & November 18, 2014. Just twice before December 4th. Atlanta has had many but mostly pre 1970
Big storm over your area (assuming SC) Monday which will stay over land coming north over PA and will bring us rains here and snowstorm for Midwest. The cold behind it will be interesting to watch.
Snow for the smokies?
A cut off low would definitely do that but not widespread below normal like shown on map. When New England is above normal and it's because of blocking in the Atlantic, the South will see these cold dips.
Looking at the 500mb maps looks like a large area that gets "trapped" while there is positive heights to the north of it. Reading the discussion.....
"Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EST Wed November 25 2020
Enhanced probabilities for near to above normal temperatures are favored across most of the western and northern CONUS, under predicted ridging and associated with positive 500-hPa height anomalies.Below normal temperatures are likely across much of the southeastern CONUS, in association with the trough over the eastern CONUS. Below normal temperatures are favored over western Mainland Alaska and the Aleutians, while near to above normal temperatures are more likely across eastern Mainland Alaska and the Alaska Panhandle, consistent with the GEFS and ECMWF Calibrated Reforecast tools."
This map is for one day but you can see why the 6-10 "average" is showing above normal probabilitys in the north and below in the south.
Also factor in clouds/rain for the south which will hold back daytime temps!
Even with the ridge, its quite unusual though how Atlanta will be colder than Montreal early next week...
But once the chill settles up north, it doesn’t seem to budge, even though it is less intense. Down south I see it rebounded nicely back to around 60 after one day in the 40’s.
Yesterday hit 73 for Thanksgiving. Next Tuesday holding steady with a forecast high of 41. Just gonna have to enjoy more 70s today and tomorrow cause the cold is coming.
Snowfall amount possibilities look to be going up bit in my area, but really depends on the track of the ULL.
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. It’s on a weekday too, so I’ll be indoors working just seeing the snow fall...
