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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
328 am CDT Thursday may 28 2015

Synopsis...
issued at 320 am CDT Thursday may 28 2015

High pressure in firm control early this am but beginning to shift
east toward the Ohio Valley with light southerly return flow
developing. Active convection /several linear clusters/ found
across portions of the central and Southern Plains early this am
in vicinity of stationary frontal zone and within plume of
deeper moisture aided by several mesoscale convective vortices.
Over next 24 hours the flow aloft will become southwesterly and will
shuttle these disturbances northeastward bringing rain chances
back to the area.

&&

Short term...(today and tonight)
issued at 320 am CDT Thursday may 28 2015

Today... high pressure will remain the dominant feature while
shifting into the Ohio Valley. Surface winds will back to
southeast and increase to around 10 to 15+ miles per hour and continue to
draw in drier air thus chewing away or eroding any precipitation
initially this afternoon...with just slight chance of a shower or weak
storm far SW County Warning Area late PM ahead of initial shortwave. Overall
just partly to mostly sunny with mainly high clouds.
Southeasterly wind direction not favorable for much warmup and
prognosticated low level thickness and verification of highs from yesterday
along with trajectory method all supportive of highs in range
from 79-84 and with comfortable humidity levels should make
for another very fine late Spring day.

Tonight... southwest flow and several shortwaves will result in
developing rain chances. Southeasterly flow through 850 mb
still ushering in drier air from departing high and thus limiting
moisture axis and subsequent better precipitation chances to western County Warning Area...
although small precipitation chances exist eastern County Warning Area late evening/overnight
with potential warm advection Wing with veering low level jet
ahead of more widespread activity lifting through central Iowa. Lows
generally in range from 59 to 64.

Long term...(friday through wednesday)
issued at 320 am CDT Thursday may 28 2015

Main forecast concern for the long term are the chances for rain
and thunder at the beginning of the period. Little change from
todays forecast and last nights forecast is expected. After this
system moves through...we see a quite rest of the extended
forecast.

Friday afternoon we should be sitting in the deep moisture. The
large...ill defined 500 mb wave will be moving into the area. Like the
day shift noted...there is a lack of strong shortwave with this system.
Current feeling is that convection will become more numerous in the
afternoon as the front approaches the area. Insolation will help to
build a healthy amount of cape for thunderstorms and possibly strong
updrafts. With the weak shortwave there is a lack of shear...in fact
deep layer is shear is 20 knots or less. Convection on Friday will
be dictated by cold pools and be multicell or single cell in nature.
Therefore thunderstorms will not last long and the threat for severe
weather will be very low. The flow...and residual moisture in the
area will lead to high precipitable waters . With the thunderstorms and high
precipitable waters ....localized minor flooding could occur. The front should move
through the area on Saturday day and will lead to a dry Saturday
evening.

Cooler and drier air are still on tap for Saturday night and Sunday.
After this the flow becomes more zonal...this will lead to a gradual
warm up across the area. Midweek we could see return moisture and
possibly and active weather pattern.

&&

Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1140 PM CDT Wednesday may 27 2015

VFR conds through this taf cycle as high pressure over the area
tonight gradually shifts to the east on Thursday. Variable but
mainly south winds tonight around 5 knots or less then southeast
to south 10 to 15 knots on Thursday into Thursday evening. Did
introduce a vcsh at kcid Thursday evening as moisture begins
returning to the area...with more widespread showers and thunderstorms
after 06z/29.

&&

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

$$

Synopsis...05
short term...05
long term...Gibbs
aviation...haase

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