Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Lincoln Illinois
334 am CDT Thu Jul 31 2014
issued 311 am CDT Thu Jul 31 2014
very little changing in this forecast. Deep low over southeastern
Canada keeping the eastern half of the country dominated by the
500mb trof. Northwesterly flow over the plains and into the
Midwest. Ridging over the west building up some warm air that will
start to edge towards the region by the end of the forecast
period. Diurnal element to cloud cover and some shower activity
possible to the northeast today...and a series of waves diving
into and around the upper trof will bring better chances for
scattered showers/thunderstorms for Friday and Saturday. Watching
forecast soundings for tomorrows potential thunderstorms and
severe weather chances. Forecast drying out for the latter half of
the weekend and into Monday until another wave moves on the
western coast, kicking the eastern trof out of the stagnant
pattern. A more progressive series of waves begins to drive better
rain chances for the remainder of the forecast.
Short term...today and tomorrow...
mild again today with light winds, just below normal Max temps.
Sunshine and afternoon clouds with some of the heavier clouds to
the northeast possibly providing a sparse shower. Tomorrow,
chances improve with a wave diving into the trof and enhancing the
afternoon instability. Wind profiles very weak, but lower freezing
level and pretty good lapse rates tomorrow afternoon could result
in some good updrafts should thunderstorms develop. Storm Prediction Center has put
the area in a see text for marginal hail threat with the daytime
heating/shortwave thunderstorms in the afternoon.
Long term...Saturday through Tuesday...
models beginning to send another wave into the trof for Saturday,
with almost a repeat of Friday with similar forecast soundings.
Beginning to trend the forecast to scattered showers and
thunderstorms for Saturday as well should the signal continue.
Though the thunderstorm development will be countered by
increasing subsidence with ridge moving closer to the area. High
pressure dominating remains of weekend as the sfc ridge axis moves
into the region. Winds remain light and variable and dry forecast
as the upper trof finally starts to progress across into the NE.
Chances for more significant weather starting to return tues/Wed
as a more active and progressive flow sets up across the country.
issued 1128 PM CDT Wed Jul 30 2014
Not much needs to be changed with the previous taf set.
Light/variable winds overnight to become more westerly for a time
late Thursday morning into the afternoon, then light/variable
again in the evening. Have a bit of concern with potential for
light shallow fog toward sunrise, though this would have no
substantial depth as the forecast soundings show dry conditions in
the lower levels. Will leave this out for now and continue to