Fall 2013 Thread — Northern Hemisphere (hottest, Portland, sky, snow)

[Patricius Maximus]

It looks like the ridge is migrating northeastward towards Greenland. Curious .

[Mac15]

Originally Posted by B87

Either the central Atlantic or North Africa.

Ugh come on now. I get airmasses from Greenland too.

[chicagogeorge]

Originally Posted by B87

Either the central Atlantic or North Africa.

I don't doubt that the UK to some extent gets all the influences from the graph that you posted, but what is the most frequent? The Atlantic right?

[B87]

The most common wind direction in London is SSW, then SW, then W, then S. Atlantic mT is the most frequent.

[Cambium]

How about what the NAM12z is showing for Wednesday's max temp between 11am and 2pm.

[Mac15]

36c in september.

Boke! Boke!

My common wind directions are nw and sw.

So my weather originates in Greenland and the Azores.

[chicagogeorge]

Originally Posted by B87

The most common wind direction in London is SSW, then SW, then W, then S. Atlantic mT is the most frequent.

and for us

Chicago’s average wind speed is about 10 mph, which ranks it among the windiest 25 percent of American cities. Winter and early spring are the windiest times of the year, with the average wind speed topping 11 mph. April is the windiest month, averaging 11.3 mph while August claims the lowest, averaging 7.9 mph. Lake Michigan has a pronounced effect on Chicago’s winds during the spring when the cold lake water generates frequent lake breezes. During most of the year the city’s prevailing wind direction varies between west and south, but from March through May, chilly northeast winds dominate.
May has the highest frequency of northeast winds, occurring on about 45 percent of the days

March thru May would probably average 2C warmer if not for lake breezes.

[Cambium]

You guys like technical? Check out NWS Albany's discussion. Very long!
National Weather Service Text Product Display

• Cold front was getting pushed by the 250mb jet stream.
• 4000 foot temps dropping to 2C
• Winds mixing from 6000' to surface will hold back CAA today
• Dewpoints not low enough to warrant below freezing temps
• The 4000' Jet will drive higher dewpoints in Monday with a possible MCS
• They are relying on the Euro and NAM. Not GFS

THE COLD FRONT WAS GETTING A PUSH BY A 100KT H250 JET WHICH HAS
INTERSECTED IT. CLOUDS WILL LINGER A LITTLE WHILE BEHIND IT...BUT
THEY LOOK TO GRADUALLY BREAK UP DURING THE AFTERNOON.

A GUSTY NORTHWEST WIND WILL ENSUE BY AFTERNOON WITH ALL SHOWERS
ENDING. THE BREEZE WILL AVERAGE 10-15 MPH GUSTING TO 25 MPH. H850
TEMPERATURES WILL DROP SLOWLY THROUGHOUT THE DAY...AND WILL BE DOWN
TO ABOUT +2C ACROSS OUR NORTHERN AREAS BY DAY/S END...AND ABOUT +6C
TO OUR SOUTH.

GOOD MIXING TO ABOUT 6000 FEET WILL SLIGHTLY NEGATE THE COLD AIR
ADVECTION PROCESSES. ASSUMING WE GET A FAIR AMOUNT OF SUNSHINE
DURING THE AFTERNOON...WE EXPECT HIGH TEMPERATURES 70 TO 75 IN THE
HUDSON VALLEY...BUT ONLY IN THE 60S ACROSS THE HIGHER TERRAIN.

BASED ON CURRENT UPSTREAM DEWPOINTS NO LOWER THAN THE MID 30S AND
THIS WARM AIR ADVECTION...WILL KEEP LOW TEMPERATURES GENERALLY ABOVE
FREEZING EVEN IN THE COLDEST SPOTS. WE WILL FORECAST PLENTY OF MID
30S THOUGH NORTH OF THE MOHAWK VALLEY AND THEREFORE HAVE ISSUED A
FROST ADVISORY AFTER MIDNIGHT THROUGH 800 AM MONDAY. OVERNIGHT LOW
TEMPERATURES SOUTH OF THE FROST ADVISORY WILL DIP TO AROUND 40

IT STILL LOOKS AS IF AN H850 JET OF 30-40KTS WILL DRIVE MUCH HIGHER DEWPOINTS INTO THE MID LEVELS OF THE ATMOSPHERE AS WELL AS BRIEF PERIOD OF ISENTROPIC LIFT PROCEEDING A
SURFACE WARM FRONT. WE LEAN WITH THE 00Z NAM AND ECMWF WHICH BOTH
INDICATE SHOWERS WILL DEVELOP...PERHAPS EVEN AN MCS ACROSS MAINLY
AREAS FROM THE CAPITAL DISTRICT NORTHWARD

[Cambium]

Dear Atmosphere,

I appreciate you bleeding cold air down from the Arctic all these times but please save these setups for the winter months.

Euro12z 850mb anomaly. Those 8-12 below normal anomalies eventually move easterward. Even though these setups aren't sustained, we're seeing these a lot now. This is for next week.

Put it this way... Normal temps at 4000 feet over Albany today is 10°C. Normal for December 8th is -6°C. So if its 10 below normal in December that can translate to near 0°F surface temps. Fun Fun Fun.

It's only September. I was hoping I wouldn't see this happen yet though

[chicagogeorge]