Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Paducah Kentucky
958 PM CST Sat Feb 28 2015
issued at 958 PM CST Sat Feb 28 2015
Going forecast pretty much on track. Around 3 inches of snow Mount
Vernon Illinois area...2 inches Perry County Illinois. Radar
mosaic shows a decrease in the solid area of snow to our west and
southwest. Still expecting occasional light freezing rain or
light snow across the advisory area overnight. Coverage should be
more scattered in nature vs. What we have seen this evening. West-southwest
Short term...(this evening through monday)
issued at 307 PM CST Sat Feb 28 2015
Quite a lot going on in the short term. The first system will
bring a round of wintry weather to parts of our forecast area
tonight and Sunday. The second and bigger system is during the
long term period.
Latest radars and surface reports indicate a large area of snow
across Missouri...mainly northwest of a kcgi to kpof line. This
snow is driven by rather strong isentropic ascent/warm advection
aloft. A swath of heavy snowfall amounts will occur over
Missouri...Illinois...and Indiana. The main concern is how far
southeast the edge of the heavy snow will come. Model soundings
for kfam and kslo indicate nearly all snow...and quite a bit of
it. Model soundings for kpah/kcgi/kevv indicate very little if any
snow. The new forecast will essentially be the same as the
previous forecast with only a few tweaks. The heaviest snowfall
should be along the northwest fringe of the forecast area...from
Mount Vernon down to Perryville. Amounts could reach warning
criteria of 4 inches there. Expect a pretty sharp gradient down to
about an inch in the kmdh area.
The main concern across southwest Indiana...far southern
Illinois...and much of southeast Missouri is a period of freezing
rain tonight. Amounts will be less than a tenth of an inch...but
could still cause hazardous conditions. Will continue the
advisory in the same areas...but expand it across the remainder of
southwest Indiana. Quantitative precipitation forecast will taper down to almost nothing along the
Tennessee border...where temperatures will stay above freezing all night.
As low level warm advection continues on Sunday...the
precipitation will change to rain by noon in all areas except
possibly north of Interstate 64. There should be a diminishing
trend in the rain as the strongest isentropic ascent shifts north
and east of our region. Dense overcast should keep highs mainly in
The precipitation will end Sunday night as surface high pressure
builds into our region. Temperatures may fall just below freezing prior
to the end of the rain...so will maintain a mention of freezing
rain. Any freezing rain would be rather brief. Monday appears to
be the dry day as the high passes by just to our north.
On Monday night...precipitation associated with the second bigger
system will start to overspread our region. There may be a period
of freezing rain at the onset in much of southern Illinois and
southwest Indiana. Temperatures should slowly rise much of the night as
winds become southeasterly.
Long term...(tuesday through saturday)
issued at 307 PM CST Sat Feb 28 2015
Low forecast confidence in the long term period as models still
showing some disparity in the handling of system to affect the
region Tuesday through Wednesday night.
The short term period starts off with a warm front just to our north
with our County Warning Area being in the warm sector with elevated instability
above a low level inversion. Therefore have high probability of precipitation (showers) on
Tuesday with chances for thunder. Thunder chances may continue into
the evening hours over the southeast half of our County Warning Area.
After having some of the warmest temperatures we have seen in a
while on Tuesday...a very strong cold front will blast across the
County Warning Area Tuesday night. Temperatures will begin to plummet in the wake of
the front. As precipitation diminishes from northwest to southeast
Tuesday night...precipitation may change over to snow or sleet over
the far western and northwestern sections late.
On Wednesday the GFS brings another surge of quantitative precipitation forecast over the southeast
half of the County Warning Area while the European model (ecmwf) lingers little to nothing over the
far southeast corner of our County Warning Area. Not sure which model will verify
best...but wherever precipitation reaches the ground on
Wednesday...it should change over to all snow over the western and
northwestern sections with a mix of rain and snow elsewhere.
Wednesday night precipitation should fall as snow before ending with
minor accumulations possible over our County Warning Area...especially the southeast
sections. We will be keeping a close eye on this system and will
undoubtably continue to make adjustments as necessary. Stay tuned.
From Thursday on...with high pressure at the surface and flow aloft
becoming more zonal...the region should remain dry with temperatures
remaining below normal.
issued at 1135 am CST Sat Feb 28 2015
VFR conditions are expected to persist through the afternoon hours.
There may be some light snow or flurries at any of the taf
sites...but no operational impact on visibilities is expected. Precipitation will
overspread the region early this evening. Most of the precipitation is
expected to fall north of the taf sites...which should keep
conditions above IFR thresholds this evening. Precipitation type should be
mainly freezing rain. The actual duration of freezing rain will be less than indicated
in the tafs. For the sake of simplicity and brevity...freezing rain is in a
prevailing group and not in protracted tempo groups. The main
concern Sunday morning will be potential LIFR conditions in stratus
Illinois...Winter Weather Advisory until noon CST Sunday for ilz075>078-
MO...Winter Weather Advisory until noon CST Sunday for moz076-086-087-
In...Winter Weather Advisory until noon CST Sunday for inz081-082-