Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Paducah Kentucky
332 am CDT Tuesday may 5 2015
Short term...(today through Thursday night)
issued at 320 am CDT Tuesday may 5 2015
Fairly high confidence continues in the short term. Upper ridge
over the southeast United States will stay in control much of the
time...keeping rainfree and warm conditions in place. Lone
exception may be over southeast MO today as a weak h50 short wave works
its way northward on the western periphery of the high. Models
have been fairly consistent in generating some light precipitation with
that feature. Warm temperatures aloft would likely limit the chance of
thunder with this...but may throw in a few showers in around southeast MO
to cover this rain chance. Should not be a big impact. Most areas
are now running a few degrees above MOS guidance in the afternoon.
Would not be surprised to see some locations in the upper half of
the 80s the next few days...especially in sunnier locations.
Long term...(friday through monday)
issued at 320 am CDT Tuesday may 5 2015
The primary forecast challenge in the long term is the strength and
path of an upper level trough as it ejects northeast across the
Central Plains. This upper level system will determine the track of
a surface low pressure center and its associated cold front.
Regardless of model preference...it appears that warm temperatures will
continue. There is less model agreement on precipitation coverage and
As far as the daily details...
On Friday...a deep closed 500 mb low over the Desert Southwest will
send pieces of energy northeast across the Central Plains and middle
Mississippi Valley. The ridge over the eastern states will shift
to the Atlantic coast...allowing moisture and convective potential
to spread east into parts of our area. Forecast probability of precipitation will be in
the chance category across southeast Missouri and southern Illinois.
Over the weekend...model differences become larger. The 00z GFS and
gefs are considerably further southeast with the location of a
surface cold front than the 00z European model (ecmwf). The GFS Camp brings the front
all the way down to the Interstate 64 corridor...while the European model (ecmwf)
keeps the front back in the Central Plains. As a result...the GFS
Camp is wetter through much of the weekend. The forecast will be
based on a model blend...which means chance probability of precipitation regionwide through
Early next week...the remnants of the southwest 500 mb low will lift
northeast into the Great Lakes region in the form of a deamplifying
trough. The models vary with the strength and timing of the
associated cold front. The front should be over or just west of the
forecast area on Monday...so the highest probability of precipitation (near 50 percent) will
be during that time period.
Convective intensity through the weekend will likely be inhibited by
rather weak middle level flow...generally under 30 knots. There is less
model agreement on wind fields and upper level forcing early next
As far as temperatures...little change in 850 mb temperatures is forecast during
the long term. 850 mb temperatures near 14 celsius have translated to highs
in the middle 80s with abundant sun. Expect highs well into the 80s
Friday when sunshine should be plentiful. There should be enough sun
over the weekend for highs to reach the lower to middle 80s. On
Monday...the proximity of the front and its associated clouds and
precipitation could hold temperatures down somewhat.
issued at 1150 PM CDT Monday may 4 2015
Low level moisture will be increasing overnight and into
Tuesday...which will likely result in a scattered-broken VFR deck from time
to time. There are some indications that there may be enough
moisture for some isolated to widely scattered convection mainly
near kcgi/kpah. But believe the activity will be isolated enough
to preclude any mention at this time. Southerly winds will once
again gust during the afternoon with the gusts subsided after 00z.