June 2018 General Discussion

[Hoosier]

16 minutes ago, cyclone77 said:

Next weekend looking pretty toasty.  GFS not quite as hot as the Euro, and doesn't last quite as long.  If the Euro is correct we could have a couple shots at 100 degrees in the DVN cwa Sun/Mon.  Mid 20s at 850 knife in on Sunday.  May be a little tougher to get as hot as the late May episode, as the crops are much more mature, and the recent heavy rains have soaked the landscape.  Something to keep an eye on anyway.

Yeah, it has 925 mb temps over 30C into Illinois, so if that is correct and assuming mixing to at least that level would support triple digit potential.  The records for those dates also happen to be a little more vulnerable. 

[Hoosier]

LOT map

[cyclone77]

00z Euro continues to look far toastier than the GFS, including the new 12z GFS.  Gonna be interesting to see who wins this battle.  If the GFS wins out the heat will be pretty meh, and shorter lived.  If the Euro is correct there will be 2-5 days of intense heat depending on where you are in the sub.  

[Hoosier]

15 minutes ago, cyclone77 said:

00z Euro continues to look far toastier than the GFS, including the new 12z GFS.  Gonna be interesting to see who wins this battle.  If the GFS wins out the heat will be pretty meh, and shorter lived.  If the Euro is correct there will be 2-5 days of intense heat depending on where you are in the sub.  

I'd probably take a compromise for now, but would start messaging the period since what the GFS lacks in max temps, it makes up for in high dews, resulting in an uncomfortable outcome in either scenario.  

[cyclone77]

3 hours ago, Hoosier said:

I'd probably take a compromise for now, but would start messaging the period since what the GFS lacks in max temps, it makes up for in high dews, resulting in an uncomfortable outcome in either scenario.  

Yeah a compromise is definitely the smart play.  If the Euro is correct though this will be a pretty impressive bout of heat.  The new 12z is even more impressive than the 00z.  Could string together quite a few 90+ days.  DVN mentionined potential heat advisories and warnings for the weekend..

For Friday into next Monday, expect an extended period of high
heat and humidity, with highs mainly in the 90s and heat index
values likely topping 100 degrees, especially south of Interstate
80. Heat advisories and possibly warnings may be needed
eventually

 

[cyclone77]

00z GFS continues to look pretty wussy with the heat dome this weekend compared to the Euro.  Euro has consistently showed an expansive swath of 20C+ at 850 for several days, with even some 23-25C temps in our sub.  The GFS is running a good 3-6 degrees C cooler which makes a huge difference.  One of these models will bust badly at least in regard to the extent of the warmth aloft.  Surface moisture and mixing issues aside, the models shouldn't be THAT different aloft at this range.

[Hoosier]

18 minutes ago, cyclone77 said:

00z GFS continues to look pretty wussy with the heat dome this weekend compared to the Euro.  Euro has consistently showed an expansive swath of 20C+ at 850 for several days, with even some 23-25C temps in our sub.  The GFS is running a good 3-6 degrees C cooler which makes a huge difference.  One of these models will bust badly at least in regard to the extent of the warmth aloft.  Surface moisture and mixing issues aside, the models shouldn't be THAT different aloft at this range.

GGEM tiebreaker?  

[CoalCityWxMan]

Yikes 

[beavis1729]

From LOT overnight:

Last night the ECMWF with fairly strong ensemble support, depicted a strengthening upper level ridge centering itself over the Midwest and lower Ohio Valley. Since last 
night, the GFS (with ensemble support) and GEM have jumped onboard with the strong upper ridge becoming centered farther north and placing our area smack dab in the 
middle of the heat. 

The latest operational runs of the ECMWF and GFS have 500mb heights approaching record high values for Illinois for mid June this weekend with the farther north 
placement of the upper ridge  likely to keep the ring of fire convection and its associated debris well removed from the area. This should allow for sunshine and 
very hot and humid conditions with 925mb temps from the GFS and ECMWF supporting highs around 90 Friday, mid 90s Sat and upper 90s to near 100 on Sunday. 

Have nudged temps upward some from the model blend Saturday, but Friday and Sunday stand a decent shot at being several degrees warmer than currently forecast as well.

[Hoosier]

1 hour ago, beavis1729 said:

From LOT overnight:

Last night the ECMWF with fairly strong ensemble support, depicted a strengthening upper level ridge centering itself over the Midwest and lower Ohio Valley. Since last 
night, the GFS (with ensemble support) and GEM have jumped onboard with the strong upper ridge becoming centered farther north and placing our area smack dab in the 
middle of the heat. 

The latest operational runs of the ECMWF and GFS have 500mb heights approaching record high values for Illinois for mid June this weekend with the farther north 
placement of the upper ridge  likely to keep the ring of fire convection and its associated debris well removed from the area. This should allow for sunshine and 
very hot and humid conditions with 925mb temps from the GFS and ECMWF supporting highs around 90 Friday, mid 90s Sat and upper 90s to near 100 on Sunday. 

Have nudged temps upward some from the model blend Saturday, but Friday and Sunday stand a decent shot at being several degrees warmer than currently forecast as well.

Can ya tell Gino is bullish?  

They aleady have 96 in the forecast for ORD on Sunday.

[Hoosier]

2 hours ago, Hoosier said:

Can ya tell Gino is bullish?  

They aleady have 96 in the forecast for ORD on Sunday.

The record high for Chicago for June 17 is "only" 96.  So whether it was intentional or not, they are already forecasting a record tying and perhaps a record breaker at 5 days lead time.

[beavis1729]

8 minutes ago, Hoosier said:

The record high for Chicago for June 17 is "only" 96.  So whether it was intentional or not, they are already forecasting a record tying and perhaps a record breaker at 5 days lead time.

Yeah, very bullish this far out.  Hard to imagine reaching mid-upper 90s with the very wet ground and with evapotranspiration beginning in earnest...but if it does, it will be nasty.  Could be looking at a heat index in the 105-110 range.  For example, 95/75 is a 109 HI. 

I would have imagined Chicago records in June to be predominantly in the 98-102 range...but surprisingly enough, 15 of the 30 days have a record high of 97 or lower. Just shows how temps in the upper 90s or higher are very rare in Chicago...and on top of that, they occur relatively more often in July/August, even with the shorter days.  

[Hoosier]

9 minutes ago, beavis1729 said:

Yeah, very bullish this far out.  Hard to imagine reaching mid-upper 90s with the very wet ground and with evapotranspiration beginning in earnest...but if it does, it will be nasty.  Could be looking at a heat index in the 105-110 range.  For example, 95/75 is a 109 HI. 

I would have imagined Chicago records in June to be predominantly in the 98-102 range...but surprisingly enough, 15 of the 30 days have a record high of 97 or lower. Just shows how temps in the upper 90s or higher are very rare in Chicago...and on top of that, they occur relatively more often in July/August, even with the shorter days.  

The temps aloft would support mid 90s or so, even on the cooler models, so I think that should be achievable barring a curveball like excessive clouds/convection.  And yeah, this one will have a different feel from the May heat due to the higher dews.

We see a similar thing in winter with the lag time causing the colder records in January.

[Hoosier]

For the Chicago area folks, another potential thing of interest is that the earliest 80 degree low on the books is June 28.  That being said, it's going to take some things to break right to have a shot at a low of 80.  

Saturday should be hot, but not hot enough to enable enough of a buffer against the nocturnal cooling overnight into Sunday morning. So Sunday's low should be below 80. That leaves Monday. Monday may give it a run BUT it's going to depend on the frontal timing later in the day.  The 12z Euro was faster with the front and drops Chicago below 80 on Monday evening.  If that front slows down, then there might be a shot.

[beavis1729]

14 hours ago, Hoosier said:

For the Chicago area folks, another potential thing of interest is that the earliest 80 degree low on the books is June 28.  That being said, it's going to take some things to break right to have a shot at a low of 80.  

Saturday should be hot, but not hot enough to enable enough of a buffer against the nocturnal cooling overnight into Sunday morning. So Sunday's low should be below 80. That leaves Monday. Monday may give it a run BUT it's going to depend on the frontal timing later in the day.  The 12z Euro was faster with the front and drops Chicago below 80 on Monday evening.  If that front slows down, then there might be a shot.

Agree with your thoughts.

For ORD, LOT is now calling for 95 on Saturday and 97 Sunday...with lows of 78 on Sunday & Monday mornings.  Even if a low temp of 80 doesn't occur, upper 70s would still be noteworthy.  For June 18th and earlier, there have only been two occurrences of a low temp of 78.  There has never been a low temp of 79 or higher. 

- Min of 78 (6/7/1933)

- Min of 78 (6/15/1994)

[UMB WX]

I can't even remember (last week sometime) the last time we've had sunshine like today.  Looking forward to finally enjoying this sunny weekend coming up.

[Hoosier]

2 hours ago, beavis1729 said:

Agree with your thoughts.

For ORD, LOT is now calling for 95 on Saturday and 97 Sunday...with lows of 78 on Sunday & Monday mornings.  Even if a low temp of 80 doesn't occur, upper 70s would still be noteworthy.  For June 18th and earlier, there have only been two occurrences of a low temp of 78.  There has never been a low temp of 79 or higher. 

- Min of 78 (6/7/1933)

- Min of 78 (6/15/1994)

The 00z Euro had 925 mb temps of 29-30C at ORD on Sunday.  IF that is correct, then highs would approach 100. Obviously not a lock though.  100 would also be a rare occurrence this early in the year... there have only been 2 of them prior to June 17, and they were back in the 1930s.  There have also been very few of them this early at well inland sites like Rockford and Moline.

[Hoosier]

dprog/dt on the ECMWF reveals a slight cooling trend aloft for Sunday in the LOT cwa.  It's not much (925 mb temps about 0.5C to 1C cooler at most) but that would possibly be enough to cost ORD from getting to 100 since it was so borderline to begin with.  This could be model noise or a real trend.

[cyclone77]

I'm gonna go 96/98/98 for MLI for Sat/Sun/Mon.  Would like to go 100 but with the recent rains and dews in the 70s 100 is gonna be pretty tough.  

[Hoosier]

20 minutes ago, cyclone77 said:

I'm gonna go 96/98/98 for MLI for Sat/Sun/Mon.  Would like to go 100 but with the recent rains and dews in the 70s 100 is gonna be pretty tough.  

I think you're playing it well.  Kinda hard to bite on 100 at this point, although I would not be surprised if at least some of the local wx observers reach that mark (not unlike what happened in late May).

I think there's a possibility of Monday matching if not slightly outdoing Sunday in Chicago.  That smacks of one of those days where it's like 90 at 10 am, and the low level gradient should be enhanced a bit with the approach of that surface low/front.

[cyclone77]

4 minutes ago, Hoosier said:

I think you're playing it well.  Kinda hard to bite on 100 at this point, although I would not be surprised if at least some of the local wx observers reach that mark (not unlike what happened in late May).

I think there's a possibility of Monday matching if not slightly outdoing Sunday in Chicago.  That smacks of one of those days where it's like 90 at 10 am, and the low level gradient should be enhanced a bit with the approach of that surface low/front.

Yeah the last day of intense heat usually has the best potential, even if 850s have cooled a degree or two.  

DVN being pretty conservative so far, only going 94/94/92.  The early morning peeps seemed more aggressive with the heat, so it's a war of the shifts lol.

[Hoosier]

18 minutes ago, cyclone77 said:

Yeah the last day of intense heat usually has the best potential, even if 850s have cooled a degree or two.  

DVN being pretty conservative so far, only going 94/94/92.  The early morning peeps seemed more aggressive with the heat, so it's a war of the shifts lol.

Maybe I will be the one to hit 100 since there's been a local rain minimum lately 

[cyclone77]

GFS soundings show mixing up to only about 850 Sunday afternoon over northern IL.  You can see quite a bit more heating potential if it can mix higher than that.  We mixed up to near H7 IIRC back in late May.  Different setup this time of course, but 850 seems a bit low.  

[Hoosier]

00z NAM is definitely a degree or two C warmer aloft than the 18z GFS was for Saturday. 

[Chicago Storm]

Records for Chicago Sat-Mon...

Sat: 98/76

Sun: 96/77

Mon: 98/77

Sunday probably has the best chance at breaking any records. Saturday could have issues with convective debris, as could Monday.

I would go 93, 97, 95 for the period.

[cyclone77]

DVN remains somewhat conservative for the Sat-Mon period, with 94/94/93 at MLI.  

[Hoosier]

LOT explicitly has 3 consecutive 95+ days forecast for ORD.  Saturday could be the most iffy day depending on convective placement.  

A streak of 3 or more days of 95+ in June has happened 5 times in Chicago.  The earliest in June streak occurred June 13-15, 1954.  This one would be second earliest if it were to materialize.  

[cyclone77]

One note about Sat, or Fri for that matter is with such warm temps aloft, temps could really spike up if there's any late day clearing in any cloud debris.  Could see a scenario where temps jump from the upper 80s to well into the 90s after 4 or 5pm if clearing occurred.  

[beavis1729]

LOT overnight

Very little to add to the past several forecast discussions
regarding the weekend heat. There has been very little change in
forecast guidance with parameters pretty much all forecast to be
at or near record levels this weekend, supporting record or near
record breaking temperatures. Some of the hottest ambient temps
this weekend should be in Chicago area due to land surface lacking
vegetation which should keep temps a couple degrees cooler
outlying areas, but also dewpoints a few degrees higher. Generally
expecting dewpoints this weekend to be in the low to mid 70s,
though probably mid 60s to near 70 in Chicago. The somewhat hotter
air temps should partially compensate for the lower dewpoints in
the city.

Generally ran with mid 90s for Saturday, though wouldn`t be
surprised to see a few spots tag 97 or 98. By Sunday, air mass is
actually progged to warm a bit more and mid to upper 90s (hottest
in the Chicago metro) look like a solid bet with a couple triple
digit reading not completely out of the question. Dewpoints Sunday
look to be in the same ballpark as Saturday, lowest in Chicago
metro where temps should be the hottest. Guidance is in pretty
good agreement now on a early Monday evening fropa, which would
mean another day of heat and humidity Monday, In fact, Monday
could end up being one of the more humid days as moisture pools a
bit ahead of the front. These lake enhanced fronts do have a habit
of moving more quickly than guidance forecasts, so there is
certainly hope for Chicago metro area to see relief from the heat
arrive Monday afternoon.

There is a reasonably good shot that at a handful of locations,
particularly the spots with typically higher dewpoints, could
reach heat advisory criteria this weekend. Certainly wouldn`t be
surprised to see a heat advisory eventually be hoisted for at
least part of the weekend. Should see a lot of sunshine this
weekend which combined with southwest winds likely to stay up a
bit at night should set the stage for some extreme nighttime low
temps in the urban heat island area of Chicago. Low temps Saturday
and Sunday night could struggle to drop below 80 with heat
indices likely remaining in the 90s through the evening and
possibly into the early part of the overnight hours.

As you may recall, following the killer 1995 heat wave, Chicago
has had specialized excessive heat warning criteria due to the
effects of the urban heat island and greater vulnerability to
impacts of heat. At this point, it would appear to be solidly
greater than a 50% chance of Chicago reaching their 3 consecutive
days of 100-105 criteria for an excessive heat warning. Coupled
with the expectation of full or nearly full sunshine 2 of the 3
days and oppressive conditions lasting well into the nighttime
hours, have opted to issued an excessive heat watch for Cook
County. If later model runs speed up the front Monday or if
dewpoints in the city mix out more than forecast, then the watch
could be converted to an advisory.

[hawkeye_wx]

The heavy storms remained from nw through se Iowa, where more than 5 inches of rain fell in spots(Ames), but I still managed a nice 0.66" from the general rain to the northeast.

We've been stuck in the low 60s for much of the day under the dense MCS.  It's now recovering toward 70.