Spring 2015 thread (Northern Hemisphere) (snow, warm, days, storms)

[nei]

Here's my NWS forecast. Obviously aren't using that GFS output:

Friday NightMostly clear, with a low around 41.
SaturdaySunny, with a high near 71.
Saturday NightMostly clear, with a low around 43.
SundayMostly sunny, with a high near 80.

[Cambium]

Originally Posted by WayneCounty

Where is the cold coming from? You would need quite a strong arctic airmass to bring in temperatures like that in May. I have some trouble believing it will get that cold.

Canada. Still some very cold air aloft dropping down (see this post) PLUS radiational cooling will help drive any heat off the surface.

You will get it sooner then this weekend.

NWS Detroit

MAIN ISSUE THROUGH THE MID-WEEK PERIOD IS COLD TEMPERATURES TUESDAY
NIGHT AND WHETHER RADIATIONAL COOLING CONDITIONS WILL BE STRONG
ENOUGH FOR FROST FORMATION.

HIGH PRESSURE BUILDS INTO
THE WESTERN GREAT LAKES. THERE MAY BE ENOUGH OF A GRADIENT OVERNIGHT
TO PREVENT MUCH FROST FROM FORMING...

ALTHOUGH MIN TEMPS ARE
CURRENTLY FORECAST TO FALL INTO THE 32-40 DEGREE F RANGE ACROSS
SOUTHEAST MICHIGAN BY SUNRISE. THERE MAY ALSO BE SOME HIGH CLOUDS
ARRIVING FROM THE WEST AS A WEAK UPPER TROUGH BEGINS TO DROP INTO
MINNESOTA AND WISCONSIN. ITS A TOUGH CALL ON THE FROST RIGHT
NOW...BUT DID INCLUDE A PATCHY MENTION FOR THE SAGINAW VALLEY AND
THUMB WITH THE MORNING FORECAST PACKAGE.

AS MENTIONED...MIN TEMPS
WILL FALL INTO THE 30S FOR MOST LOCATIONS. THESE TEMPS ARE WELL
BELOW NORMALS WHICH CURRENTLY RUN IN THE MID 40S TO NEAR 50 FOR
LOWS...AND APPROACHING RECORDS WHICH ARE BELOW.

RECORD LOW TEMPS FOR MAY 20
DETROIT...33 (1981)
FLINT.....32 (1997)
SAGINAW...30 (1926)

[nei]

Originally Posted by WayneCounty

17 degrees In upstate NY but low 30s in northern Ontario/north central Quebec? Where is the cold coming from? You would need quite a strong arctic airmass to bring in temperatures like that in May. I have some trouble believing it will get that cold.

That 17 is from a hilly (2000 feet) location, that is prone to cold temperatures late spring.

[NorthStarDelight]

Originally Posted by nei

That 17 is from a hilly (2000 feet) location, that is prone to cold temperatures late spring.

But won't that kill the leaves on the trees that have already leafed out? I doubt it'll get that cold anyhow, just too late in the season for that.

[WayneCounty]

Originally Posted by nei

That 17 is from a hilly (2000 feet) location, that is prone to cold temperatures late spring.

Why didn't I realize that lol.

[Cambium]

Originally Posted by nei

Here's my NWS forecast. Obviously aren't using that GFS output:

Friday NightMostly clear, with a low around 41.
SaturdaySunny, with a high near 71.
Saturday NightMostly clear, with a low around 43.
SundayMostly sunny, with a high near 80.

Look at NWS for me. LMAO!!! Still has near 50°F.

Everyone should Screen shot their forecasts, lets see how much they change for this weekend.

[WayneCounty]

Originally Posted by Cambium

Canada. Still some very cold air aloft dropping down (see this post) PLUS radiational cooling will help drive any heat off the surface.

You will get it sooner then this weekend.

NWS Detroit

MAIN ISSUE THROUGH THE MID-WEEK PERIOD IS COLD TEMPERATURES TUESDAY
NIGHT AND WHETHER RADIATIONAL COOLING CONDITIONS WILL BE STRONG
ENOUGH FOR FROST FORMATION.

HIGH PRESSURE BUILDS INTO
THE WESTERN GREAT LAKES. THERE MAY BE ENOUGH OF A GRADIENT OVERNIGHT
TO PREVENT MUCH FROST FROM FORMING...

ALTHOUGH MIN TEMPS ARE
CURRENTLY FORECAST TO FALL INTO THE 32-40 DEGREE F RANGE ACROSS
SOUTHEAST MICHIGAN BY SUNRISE. THERE MAY ALSO BE SOME HIGH CLOUDS
ARRIVING FROM THE WEST AS A WEAK UPPER TROUGH BEGINS TO DROP INTO
MINNESOTA AND WISCONSIN. ITS A TOUGH CALL ON THE FROST RIGHT
NOW...BUT DID INCLUDE A PATCHY MENTION FOR THE SAGINAW VALLEY AND
THUMB WITH THE MORNING FORECAST PACKAGE.

AS MENTIONED...MIN TEMPS
WILL FALL INTO THE 30S FOR MOST LOCATIONS. THESE TEMPS ARE WELL
BELOW NORMALS WHICH CURRENTLY RUN IN THE MID 40S TO NEAR 50 FOR
LOWS...AND APPROACHING RECORDS WHICH ARE BELOW.

RECORD LOW TEMPS FOR MAY 20
DETROIT...33 (1981)
FLINT.....32 (1997)
SAGINAW...30 (1926)

We got 30s around this time in 2013 too. Yuck. I guess it is time to watch the forecast closer and be ready to bring in/cover plants.

[nei]

Originally Posted by NorthStarDelight

But won't that kill the leaves on the trees that have already leafed out? I doubt it'll get that cold anyhow, just too late in the season for that.

17°F? probably. Coldest for Alfred, NY [1770 feet] past May 20 is 24°F:

ALFRED, NEW YORK Period of Record Daily Climate Summary

May 2002 had a bunch of 26°F around May 20. I wish ours May weather was less variable. Don't need 80s or mornings in the low 40s and colder.

[Cambium]

Lets take a look at 3 maps.....

Current 850mb temps and upper airflow. You can see why its snowing and feels like teens in those areas northern plains. 850mb freezing line dropping well south. Eastern U.S still has a SW flow although clouds and other factors wont allow heat to happen in most areas of Northeast.(80s)

Think of a bowling ball.. that blue airmass over the Upper Midwest will curl around BUT ..........



On left is Wednesday... The cold air breaks up before getting to the Northeast but still just seasonable. Take note of something on the Wednesday map... Vortex is back over northern Hudson Bay. That air will start diving down

On right is Saturday... Upper Low rotates into New England carrying a NW flow and very cold air... Nice coverage of below freezing temps aloft there hence the cold temps GFS is showing.

If that Vortex was in Southern Hudson Bay and rotated around, we would be seeing historic monthly cold temps. Not gonna happen. VERY hard for the Vortex to push south this time of year.

Keep note of the arrows. Can't warm up with a NW Flow like that

[snj90]

Originally Posted by Cambium

And here's Saturday morning...

Saturday morning looks to be the coldest morning till next fall in the North East...maybe? Not sure it will get this cold though. Doubt it.

Now its getting fun again!

That looks awesome and refreshing, especially with how hot, humid, and nasty it already is today.

Jealous of the folks getting snow in the Upper Midwest...