During the late Summer, we usually see a subtle change in the weather pattern to a cooler temperature regime heading into early Fall but with a Weak La Nina in place, this Fall is turning out to be slightly on the mild side overall and dry. Just what you would expect for a Weak La Nina. HOWEVER...THAT IS ABOUT TO CHANGE FROM LATE OCTOBER ONWARD...
This has been our general weather pattern so far this Fall as our pattern has been dominated by a negative NAO (blocking over Greenland), a strong Bermuda High and the Fetch of strong Tropical Atlantic Moisture from Africa to the Caribbean. So far, we have had 16 names Tropical Systems in the Atlantic which is above average but expected during a weak La Nina. But there are signs that this dominant "Atlantic Tropical/Bermuda-Azores" pattern influence has come to and end.
Look for the transient thermal pattern to possibly start up again as early as mid to late October into November.
OFFICIAL QUAGMIRE WEATHER CENTRAL FALL 2017 OUTLOOK
OVERALL...MILD + DRY TO START WITH A COOL DOWN TO MORE SEASONAL LIKE TEMPERATURES BY LATE OCTOBER WITH RAINFALL CHANCES INCREASING SLOWLY FOR THE LAST HALF OF FALL...
OCTOBER...MILD TO START THEN NEAR SEASONAL AVERAGE TEMPERATURES OVERALL TO END THE MONTH...DRY TO START WITH AN UPTICK IN RAINFALL CHANCES.
NOVEMBER WILL SEE OUR TYPICAL FALL CYCLICAL TRANSIENT THERMAL PATTERN SET-UP (MILD TO COOL TO MILD THEN REPEAT TEMPERATURE REGIMES) AS THE "PACIFIC-ASIAN-POLAR" INFLUENCE BUILDS. EXPECT NEAR SEASONAL TO SLIGHTLY BELOW TEMPERATURES WITH NEAR AVERAGE RAINFALL.
DECEMBER...NEAR SEASONAL TEMPERATURES TO START OFF WINTER WITH A POTENTIAL TREND TOWARDS COLDER TEMPERATURE REGIMES FROM MID DECEMBER ONWARD...PRECIPITATION (RAIN AND SNOW) CHANCES WILL BE NEAR AVERAGE.
The Official NOAA Fall Outlook for 2017 October to December 2017...MILD WITH NEAR AVERAGE RAINFALL EXPECTED.
A combination of a cool first half of September, Warm last half of September into October with dry conditions, it is likely that the Fall colors are not going to be as vivid as in previous years but there will be some spots with decent colors but it will be scattered.
HOWEVER FOR THE RECORD...THIS HAS NOT BEEN THE DRIEST FALL ON RECORD FOR THE MID-ATLANTIC REGION.
Are changes on the way for a cooler end to October and perhaps another longer term cool down for November? The long range European Weeklies model hints that this could occur as we transition from a "Tropical" influence to a more "Pacific and Asian Polar" Influence in our weather pattern ahead.
As the transient thermal pattern gets rolling from the last half of October into November, look for an overal gradual transition to periods of cooler temperatures as the up and down temperature regimes take reign.
The latest ENSO indexes have the weak La Nina holding on thru the Fall peaking in December to early January. Usually Weak La Nina during the Fall months bring warm and drier conditions like we have been seeing but there are signs that as the Northern Pacific "comes to life" and this pattern is going to become cooler over time now into December.
WINTER 2017-18 OUTLOOK TO BE POSTED FIRST WEEK OF NOVEMBER 2017