September Starts Meteorological Autumn And The Temperature Outlook Shows It

September 1 is the start of a new season for meteorologists. We group seasons together in three full month periods. This is the start of Autumn for science records, even though the astronomical Autumn begins on September 22 at 9:30 AM.

Below you will find a look at the numbers for temperature and daylight for what we would normally expect throughout the month of September in Baltimore. But first, the weather outlook shows signs of the season trying to change.

NOAA Temperature Outlook

This Outlook is for NEXT WEEK (Days 8 to 14) shows a dramatic cool down expected in the middle of the nation. The west coast should be hot, while the east coast will be near normal to slightly warm. Our region is on the edge of that.

 

Jet Stream Forecast Model Simulation 

The GFS Model (which has performed rather well lately) shows the Jet Stream buckling with a deep trough next week. This will allow much cooler air to drop in from Canada.  Will we get it? Well, here it looks like we remain on the edge. It is possible we get a taste and some chilly nights when the skies clear.

 

 

Temperature Outlook: Translation

I think we will get some taste of the cool air one or two days next week, not shown here.  It’s more likely we get some nights that could drop into the 50s, if the skies clear and we get that trough to shift a little east.

 

Climate Data

The sun angle is getting lower, and daily sunlight is shrinking by more than 2 hours 30 minutes each day in Baltimore:

• September 1:  Sunrise @ 6:35 AM ; Sunset @ 7:36 PM – Length of Day = 13 hours 00 minutes and 55 seconds.
• September 30 Sunrise @ 7:02 AM; Sunset at 6:49 PM – Length of Day = 11 hours 47 minutes and 43 seconds.

That is about a loss of 1 hour 13 minutes daylight by the end of the month.

 

The Average Temperature Change 

Here’s the official climate data for Baltimore from the National Weather Service based on records since 1881.

Baltimore will average 11 degrees cooler by the end of the month.

The code at the top of each column:

• DY = Day
• NMX = Normal Max (high) Temperature
• NMN = Normal Min (low) Temperature
• RMX = Record Max/high Temperatures
• LMX = Record cool high Temperatures
• RMN = RMX = Record Main/low Temperatures
• HIMN = Record warm low Temperatures
• MXPCP = Max precipitation (daily rainfall)

Hottest: 101ºF on Sept 7 in 1881

Coldest: 35ºF on Sept 25 in 1963

Note: Normal is NOT Normal! The weather often swings from warm to cool on either end.

This initial surge of chilly air is early, so it will subside and allow the warmth to return.  I would not suggest summer is completely over. Often a big drop in temps is matched by a warm up a week or two later.  But the strong of 90 degree days will be much harder to come by.  If you ask me, it wasn’t soon enough. But I guess I should save my opinion for snow season. FITF

 

Maryland Weather 

 

 

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