Weather Wordsmithing

I’m kind of a weather geek so every morning I read the “scientific forecaster discussion” that is made available by wunderground.com as part of their local forecasts.  Just had to share this one after reading it this morning (full quote below the selections):

Primary forecast challenges this morning revolve around thunderstorm chances the next few days…followed by finding just the right word to describe how gorgeous the weather is going to be Friday into the weekend.

…so have adjusted pop grids accordingly. With the weaker cap do have a haunting feeling in the back of my mind that the lake breeze may try to fire off a shower or two given the much weaker cap today…?

Supercalifragilisticexpialidocious is about the only word that can describe how great the forecast looks by Friday into the weekend!

Thanks Izzi….you gave me a smile this morning.

Full text:

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Area forecast discussion
National Weather Service Chicago/Romeoville Illinois
642 am CDT Tuesday may 25 2010

Discussion…
335 am CDT

Primary forecast challenges this morning revolve around thunderstorm
chances the next few days…followed by finding just the right word
to describe how gorgeous the weather is going to be Friday into the
weekend.

The “butterfly effect” thunderstorms that affected the area Monday
evening into the overnight hours have finally diminished this
morning. The “butterfly” responsible for these storms appears to be
a compact vorticity that moved southwest around the northwest periphery
of the upper low over the Carolinas. This vorticity fired convection over
western Tennessee and Kentucky Monday morning. Northward surging
outflow from those storms fired a series of additional storms
progressively farther north across Illinois with the composite
outflow from all of those storms moving into our southern County Warning Area late
Monday evening. By that time…weak cold advection in the middle levels
had finally eaten away enough at the cap to allow the outflow to
push parcels to their level of free convection. Nocturnal cooling/stabilizing has finally
killed off the storms and expect US to remain dry through the rest
of the morning.

Deep easterly flow seen on the Wolcott in profiler is actually
advecting in drier air from the east into Illinois this morning.
GOES sounder derived precipitable water imagery shows this drier
airmass steadily marching westward into Illinois with precipitable
water values dropping a half to three quarters of an inch. This
drier and less unstable airmass will result in a east-west gradient
in tstorm chances this afternoon…with eastern areas likely to
remain dry while western County Warning Area stands a decent shot at seeing scattered
diurnal pulse thunderstorms fire up. WRF-arw run by weather forecast office lsx depicts
this scenario nicely with very little quantitative precipitation forecast over eastern 2/3rds of
County Warning Area…so have adjusted pop grids accordingly. With the weaker cap do
have a haunting feeling in the back of my mind that the lake breeze
may try to fire off a shower or two given the much weaker cap
today…but given the drier/more stable airmass it will be
penetrating suspect the chances of that occurring are low enough to
keep out of the forecast.

By Wednesday the front currently out in the plains will push east
toward the region…but also be washing out at the same time as it
runs into the upper ridge. While the front will be washing out…it
should encounter the lingering moist/unstable airmass over the upper
MS valley ahead of it…so that even the weak convergence with what
is left of the front likely to kick a fairly decent coverage of
convection. Deep layer shear is weak…so expect that convection
will be fairly disorganized but with a rather high coverage so have
bumped probability of precipitation up a bit over western County Warning Area. Convection should be largely
diurnal in nature Wednesday and should diminish Wednesday evening before
re-firing again along whatever is left of the front Thursday
afternoon. Given how ill-defined the front is forecast to be by then
its hard to draw a line of where there is a chance and no chance of
tstorm development. Given that uncertainty have maintained slight
chance probability of precipitation up to the WI border Thursday but have a hunch that later
forecasts will be able to remove these probability of precipitation leaving areas north of
I-80 with a pretty nice day Thursday.

Supercalifragilisticexpialidocious is about the only word that can
describe how great the forecast looks by Friday into the weekend!
Upper ridge should remain anchored over the upper Mississippi Valley
providing for subsidence and cloudless or nearly cloudless skies. In
addition…Canadian high pressure will nose down into the upper
Great Lakes providing for light northerly flow which should send the
current humid airmass well southward and knocking our dewpoints back
down into the 40s. That sets the stage for large diurnal swings with
clear and rather crisp mornings followed by sunny and very mild to
warm afternoons. Each day will feature some lake cooling…though it
should be most prevalent on Friday when background synoptic gradient
is northerly providing for a bit more umph in the inland push of the
marine airmass. Lighter gradient Saturday and Sunday will mean less
of a lake push…though still cooler conditions Lakeside.

Izzi

&&

Climate…

Not only did rockford’s 93 degree high temperature break a daily
record but it also Marks the earliest it has gotten this warm during
the year since back in 1975 when the high temperature om may 19th
got up to 95 degrees. The average first date for a high of at least
93 degrees in Rockford is June 28th. Interestingly…it was only a
couple years ago back in 2008 that Rockford didnt see their first 90
until September 2nd…what a difference a couple years can make!!

While shy of a record…in Chicago the 91 degree high tempeature
Monday Marks the earliest in the year it has gotten this warm
since 1998 when the high temperature also got up to 91 degrees.
The average first date for a high temperature above 90 degrees in
Chicago is June 14th.

Izzi

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