July 2025 Discussion-OBS - seasonable summer variability

[wdrag]

Summer variability as outlooked 6/24...  nothing outrageous outlooked as the ridge locks in near the Rockies with troughing in the east. Implies brief hot incursions with frontal passages seemingly progressive.  Heaviest rain axis continues outlooked Appalachians to the Mississippi -Ohio Valley.  

Modeling doesn't pick up excesses very well beyond 10 days.

Guidance suggests a warmer than normal month in our area.

[uofmiami]

 

[donsutherland1]

Below is some historic data on the frequency of 90° or above highs and 80° or above lows.

The frequency of 90° lows has decreased in parts of the July while increasing during roughly the July 15-25 period. Central Park's dense tree cover has likely contributed to the decreased frequency in parts of July. Central Park has seen 10 days with a decrease, including five days with a greater than 5 percentage point decrease. The nearest station (LaGuardia) has seen an increase on all but 3 days in July. Newark has seen a decrease on only 4 days. Both LaGuardia and Newark saw a decrease of greater than 5 percentage points on one day. JFK is affected by the sea breeze, which adds to the variability. Nevertheless, JFK has seen a greater than 5 percentage point decrease on only one day.

 

 

 

[wdrag]

Looks like CPC continues with a warmer than normal July as posted in their 6/19 outlook.

 

Here are some steps in that direction. Their updated monthly should post 6/30.

Below from yesterday 6/27 for June periods as listed.

 

[forkyfork]

big jump toward an eastern ridge

[LibertyBell]

31 minutes ago, forkyfork said:

big jump toward an eastern ridge

hopefully like the last one no sea breeze (at least for one or two days)

[wdrag]

2 hours ago, forkyfork said:

big jump toward an eastern ridge

Looks temporary and not quite as strong but it will get into the 90s vcnty NYC (INLAND for sure again) at least several days between July 5-10. Seems to shift west after the 10th but part of the variability. 

[LibertyBell]

1 minute ago, wdrag said:

Looks temporary and not quite as strong but it will get into the 90s vcnty NYC (INLAND for sure again) at least several days between July 5-10. Seems to shift west after the 10th but part of the variability. 

what causes all this variability in recent heatwaves (since 2013) that keeps them short, Walt?  Compared to much longer heatwaves for example in 1944, 1953, and more recently 1980, 1993, 1999, 2002, etc that lasted much longer.

1980 for example, we basically had a heat ridge sitting over our area for 3 months (June 20th through September 20th).

 

[forkyfork]

40 minutes ago, wdrag said:

Looks temporary and not quite as strong but it will get into the 90s vcnty NYC (INLAND for sure again) at least several days between July 5-10. Seems to shift west after the 10th but part of the variability. 

pieces of heat with fronts, above normal overall

[LibertyBell]

31 minutes ago, forkyfork said:

pieces of heat with fronts, above normal overall

sucks no 1980 style continuous heat, but at least the peaks are higher this year (for us anyway).
 

[SnoSki14]

Heat without activity is a bore. It's the cold/dry equivalent 

[wdrag]

15 minutes ago, LibertyBell said:

sucks no 1980 style continuous heat, but at least the peaks are higher this year (for us anyway).
 

You'll get yours if we shift into a significant wet tropical season Aug-Sept.  No idea on reasoning for a lot of climate variability---

[forkyfork]

24 minutes ago, LibertyBell said:

sucks no 1980 style continuous heat, but at least the peaks are higher this year (for us anyway).
 

june 1980 was below average with a few nights getting into the 40s

[LibertyBell]

31 minutes ago, forkyfork said:

june 1980 was below average with a few nights getting into the 40s

The heat was just getting started in the final week of the month and lasted into September

A nice dress rehearsal for 1983

[LibertyBell]

42 minutes ago, SnoSki14 said:

Heat without activity is a bore. It's the cold/dry equivalent 

It depends on how extreme it is.  If it goes below zero then it's interesting (same as 100+).  There does need to be activity around the bookends though (just like with winter.)  January 1994 was much more fun than January 1985.  Both went below zero, but January 1994 had much more activity.

 

[Sundog]

1 hour ago, forkyfork said:

june 1980 was below average with a few nights getting into the 40s

Those were the days

[LibertyBell]

18 minutes ago, Sundog said:

Those were the days

No they weren't  Only the last 10 days of June are part of summer.  If you're familiar with 1980 there was historic heat for all of July and all of August and the first three weeks of September that covered the entire CONUS except for the extreme Pac NW and Maine.  A thousand people died in Saint Louis alone from the intense heat (1995 Chicago was similar to 1980 St. Louis.) NYC's couplet of July and August is still the hottest 62 day period on record and August 1980 is the hottest August on record and the only one with a mean temperature of 80.0 or above.

But 1983 was an even hotter summer (going by the metrics I use.)