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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
1249 PM CDT Thursday Jul 30 2015

Synopsis...
issued at 243 am CDT Thursday Jul 30 2015

Mostly clear and quiet night across the Midwest with temperatures
and light winds resulting in the Mercury ranging from 59 to 65
degrees at 2 am. All analysis tools show little change from past
24 hours into Friday morning for typical late July quiet weather.
Upstream energy supports northwest flow into the weekend with near normal
temperatures and some chances of showers and thunderstorms.

&&

Short term...(today and tonight)
issued at 243 am CDT Thursday Jul 30 2015

Short term forecast confidence assessment...good to excellent or
above average to well above average. Little sensible weather issues
with most significant challenge is dewpoints likely a bit too high
as discussed yesterday with bl mixing middle to late day and surface
winds slightly gustier than solutions due to mixing.

Today...sunny to mostly day similar to Wednesday. Highs most locations
a few degrees warmer and dewpoints a couple of degrees higher. Middle to
late day mixing to allow for winds to increase to 10 to 15+ miles per hour with
some gusts to around 20 miles per hour north sections. Overall another warm but
decent late July day.

Tonight...clear skies again with light winds will once again allow for
good bl decoupling as is happening tonight with mins most locations
on low end of coolest guidance. Overall...lows should be a couple of
degrees warmer than tonight. This would suggest around 60f in coolest
areas in north sections to around 65f in south sections.

Long term...(friday through wednesday)
issued at 243 am CDT Thursday Jul 30 2015

Forecast focus on an active northwest flow with temperatures
trending downward next week.

Friday...a weak cool front will arrive in the afternoon into early
evening with enough instability and moisture pooling along the front
to support isolated to widely scattered thunderstorms. I will
confine the small probability of precipitation to our southern County Warning Area with the timing of the
front during peak heating. However...lack of a significant short
wave precludes mentioning any higher probability of precipitation. Maximum temperatures will
range from the middle to upper 80s.

Saturday through Sunday...short wave in the northwest flow will
provide large scale ascent/divergence aloft as it tracks into the
County Warning Area Saturday night. A low level jet will be intensifying/increasing
warm air advection which will interact with a cold front arriving.
Deep layer shear of about 40 knots and ample instability should support
a few supercells capable of producing large hail and damaging winds
during the evening. This should upscale into a larger mesoscale convective system overnight
with continued warm air advection with a damaging wind threat. The
storms should diminish Sunday morning but may refire in our south
along what should be an old outflow boundary.

Monday through Wednesday...the dvn County Warning Area will be in a battle zone
between the heat dome in the southern states and an unseasonably
strong upper low diving southward towards the Great Lakes. This will
set up an east-west frontal boundary near or over the dvn County Warning Area with
periodic mesoscale convective system development in the area. Daily chance probability of precipitation will be in
the grids with plenty of room to go higher when timing/placement of
any mesoscale convective system becomes more reliable. Maximum temperatures will be in the
upper 70s to lower 80s with readings trending to below to well below
normal late in the week.

&&

Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1230 PM CDT Thursday Jul 30 2015

High pressure across the Central Plains and into the middle MS River
Valley will maintain VFR conditions into tonight and most of Friday
morning. West winds of 8-12kts this afternoon will become light
west to southwest overnight as the ridge sinks to the south. A
weak wave aloft embedded in steering northwest flow may try to
scoot into the area/southeastern Iowa Friday morning but hopefully just
produce some middle level VFR clouds in those areas...although a few
models try to break out isolated to widely scattered showers from
13z-16z or so. ..12..

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

Synopsis...Nichols
short term...Nichols
long term...haase
aviation...12

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