Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Paducah Kentucky
315 am CDT Thu Oct 2 2014
Short term...(today through Saturday night)
issued at 315 am CDT Thursday Oct 2 2014
Low pressure was over the Southern Plains early this morning.
Wvapor revealed sharp S/WV over the central rockies moving east
with broad SW flow ahead of it. Convection was north and well
west of our area early on. Think from now through mid morning
it will remain fairly quiet across our cwfa, per the latest hrrr
and 12km NAM solutions.
Will also follow the hrrr/NAM/sref solutions from midday into
the afternoon. Expect a minor wave to interact with increasing
instability to produce convection into semo and SW Kentucky
moving NE across the region through the afternoon. Will go with
chance/sct type pops given uncertainty with respect to coverage.
Respectable instability develops, but mid level lapse rates and
speed shear remains weak, so maybe a strong storm or two. Low level
lapse rates are more favorable, which may yield a few stronger
Overall, no change in thinking from last night, in that the Storm Prediction Center
slight risk is probably too broad brush and too far east across
our area. The west 1/2 of the current day 1 is where the better
chances of severe should be late today/tonight. Models still
depict only marginal wind fields. NAM likely over done with 06z
850mb winds and instability as it usually is. The European model (ecmwf) and GFS
wind fields are probably more realistic. Mid level lapse rates are
quite marginal. 0-3km bulk shear only up to 30 kts or so. So
again, strong wind gusts here and there, and some low end hail
possible. But only isolated severe gusts should a segment or two
pulse up, maybe near 60 mph, with the best chance of that from
semo, into far west Kentucky. That's if the NAM (more robust with low
level jet and lingering surface based instability through 06z) is
correct. Otherwise categorical pops tonight as the band of
convection moves from west to east across the area. Upwards of 1
inch of rain on average. Isolated higher amounts.
The band of convection will move quickly east and out of the area
early Friday morning. However, during the afternoon, another lobe
of energy will swing east across MO, into Illinois. Have a slight chance
of thundershowers with this feature mainly across the northern 1/2
of the area. It will not hang around long, with dry, cooler
conditions taking over Friday night through Saturday night as high
pressure slides southeast from the plains to the Gulf Coast states.
Saturday will be rather cool as has been advertised.
Long term...(sunday through wednesday)
issued at 315 am CDT Thursday Oct 2 2014
Much of the long term will be dominated by an upper level low
centered over Ontario province in southern Canada. South of this
low, a broad upper level trough will envelope a large part of the
central and eastern U.S.
Mainly dry conditions will result. However, a few impulses of energy
rotating around the low and through the base of the trough are
forecast to bring an increase in clouds and at least a small chance
for precipitation early next week. Models are not quite on the same
Page, so overall confidence is relatively low at this point.
However, the greatest precipitation potential appears to be centered
on a window from Sunday night into Monday night. Will keep thunder
out of the forecast at this point, though if the European model (ecmwf) is right, at
least some marginal instability may be present.
Temperatures during this time will remain below normal. Highs Sunday
and Monday will range from the upper 60s to lower 70s, with lows in
the upper 40s to lower 50s. A warming trend will begin Tuesday and
really kick in by Wednesday as the trough shifts east and allows a
ridge to build in its place. Highs by Wednesday may push 80 degrees
in some locations.
issued at 548 PM CDT Wednesday Oct 1 2014
Warm advection was driving some mid clouds into semo nearest kcgi
and kpah terminals, and this may linger overnight. Frontal
associated convection and debris cloud upstream will near all
terminals tmrw, with scattered diurnally driven low VFR cu bases
developing underneath. Pcpn should hold off until front enters pic
tmrw nite, but isold pre frontal warm advection clouds/associated
showers will be monitored closely.