Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KILX 272312

Area Forecast Discussion
National Weather Service Lincoln IL
612 PM CDT Sun Jul 27 2014

ISSUED 200 PM CDT Sun Jul 27 2014

18z Surface map indicating cold front has shifted into extreme
southern Illinois with a secondary boundary/dew point discontinuity
located from near Chicago southwest to Bloomington to just south
of Quincy. Early afternoon temps have risen into the mid to upper
80s with dew points still in the 70s to the east of the secondary
boundary, with upper 50s to lower 60 dew points filtering southeast
into west central IL. Along and just to the east of this dew point
discontinuity, widely scattered showers and thunderstorms have
developed. Local objective analysis indicates Mixed Layer Capes of
1500-2000 J/Kg to the east of boundary with minimal low level
convergence noted at 18z. 0-6km bulk shear values in the 50-60 kt
range, so any strong updraft along the boundary will have the
capability of producing gusty winds. Visible satellite data showing
quite a bit of wrap around moisture shifting south into the lower
Great Lakes early this afternoon as an upper level trof shifts

SHORT TERM...Tonight through Wednesday

Main forecast challenge this period will be with temperatures and
amount of cloud cover and possible showers associated with the
aforementioned Great Lakes trof as it slowly settles south into
the upper Midwest early this week. Models in decent agreement with
respect to the trof deepening in over the Great Lakes this week.
As the cooler temps aloft and high based cu field settle south,
we may see some shower activity across the northeast into early
this evening but several of the hi-res models suggest the bulk of
the shower threat should be east of our area by early this eve so
at this point will keep the evening portion of the forecast dry.
Forecast soundings have suggested the potential for some ground fog
development by morning but with as much mixing that is occurring
this afternoon, will hold off mentioning for now. The southeast may
be close as they will be last to really mix out later this afternoon,
but even there will keep it out of the forecast.

Rather quiet weather expected over the remainder of the forecast period
with the upper trof settling south over the next several days. As temps
aloft continue to cool, our chances for some diurnally driven showers
and storms will increase, especially as we head towards midweek and
beyond. Latest NAM-WRF model indicates parts of our area may see some
afternoon showers tomorrow afternoon. Think that model may be too
strong aloft with the trof and associated cold pool so will tend to
side more with the GFS solution in keeping the area dry for tomorrow.
Temperatures will be cooler than normal but on the pleasant side with
afternoon temps in the mid to upper 70s tomorrow and Tuesday and around
80 by Wednesday with early morning lows in the mid 50s to near 60.

LONG TERM...Thursday through Sunday

Low ensemble spread with the trof expected to drop south into the
Ohio Valley by the weekend. The real challenge will be how the
medium range models handle the individual shortwaves rotating thru
the trof and combining with daytime heating and cool temperatures
aloft to bring about daily chances for mainly afternoon and evening
showers during this period. 850 temp progs suggest not a great deal
of temperature change during this period. We should edge back to
or just above 80 for daytime highs with early morning lows around
60 degrees.



ISSUED 612 PM CDT Sun Jul 27 2014

VFR conditions will prevail at all sites next 24hrs. Scattered
clouds at around 6-7kft remain over the area, but given they are
diurnal, they should mostly dissipate this evening around 2z.
Skies will then be mostly clear to clear overnight. Then CU will
develop again tomorrow morning, starting at around 4kft but rising
up to 7kft again tomorrow afternoon. Winds will be northwest and a
little breezy this evening, but should diminish around 02z and not
have any gusts. Tomorrow winds should be more northerly with some
gusts, but only to around 20kts.




$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.