Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Little Rock Arkansas
845 PM CDT Monday Sep 1 2014
Earlier update to end convection chances in the south as activity
weakened and dissipated after sunset. This evening convection...some
severe...is on going over southeast Kansas...NE OK...to SW MO. This is in
response with low level moisture in flux...a boundary in the
area...upper short wave energy...and quite unstable air mass. Trends
have convection moving almost due east with steering flow...while
southern most storms showing some trend to the southeast. Have chance probability of precipitation
over northwest to northern Arkansas tonight and will keep this. Dry the rest of
the state. Short range models are consistent to trend convection...
albeit weaker...into northern Arkansas late tonight and Tuesday morning.
Forecast has this trend...while southern extent of convection is a
bit uncertain. Slight chances much of central to south on Tuesday
will suffice at this time...until next model run and latest trends.
Will fine tune a few elements with late evening update but no major
changes expected. (59)
Previous discussion... /issued 641 PM CDT Monday Sep 1 2014/
convection has developed along front in Missouri and
Oklahoma...with outflow boundary moving north near the northern
taf sites. Think that much of the thunderstorms and rain will remain north of the
border through 06z...and have included thunderstorms in the vicinity/probability 30 groups during
the overnight hours. For the south...stratus will develop
again...and will mix out during the late morning. Have kept precipitation
mentions out of central Arkansas with this taf cycle.
Previous discussion... /issued 254 PM CDT Monday Sep 1 2014/
Short term...tonight through Thursday night
The overnight mesoscale convective system has completely dissipated. However...residual
outflow boundaries could act as a focus for isolated storms through
the remainder of the day. Meanwhile...diurnally driven convection
will continue across the parts of southern and eastern Arkansas.
Showers and thunderstorms are expected as another mesoscale convective system develops
across southeast Kansas and SW Missouri late tonight and into the
overnight hours. The system will generally remain across southern
Missouri along a slow moving front...with zonal flow aloft not
allowing for much of a push southward. Although there could be
some locally heavy rain possible...much of northern Arkansas remains in
a precipitation deficit and expect any possible flooding to be localized
Expect that some overnight convection will dwindle after sunrise
on Tuesday...however unsettled conditions will be noted through
the day. The best chances will remain across the northern half on
the state...depending on the how far the front moves south. Precipitation
chances will still be possible across parts of east-northeast Arkansas
Tuesday night into Wednesday...with the boundary lingering close by.
By middle week...high pressure will build back in across the
southeastern Continental U.S. And dry weather and warmer temperatures
returning later in the period.
Long term...Friday through Monday
Model remain in fairly good agreement today indicating a broad upper ridge in
place across the southern states at the start of the period. Just some widely
scattered diurnal convection expected on Friday.
Heading into next weekend...both the GFS and European model (ecmwf) indicate that the upper
ridge will shift a bit westward into the plains states. This will allow a new
cold front to approach Arkansas from the northwest...eventually moving through the forecast area Sat and
sun. Scattered rain showers/thunderstorms and rain will accompany the fnt across the region. Appears
cooler and drier conds will return by the end of the period as the frontal
boundary stalls out S of the region.