Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 281626
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1026 AM CST Fri Feb 28 2014
ISSUED AT 1025 AM CST FRI FEB 28 2014
Upper level system heading our way is currently in eastern
Oklahoma...and will continue moving east into northeast Arkansas
by 00Z. Moisture is definitely taking its time getting here and is
much slower than previously thought. Still appears parts of
southeast Missouri have the best chance to see any light rain
later this afternoon given current trends and latest model guidance.
The system weakens as it heads into our region, so, as we head
into the evening hours...chances for rain lessen further eastward.
Will maintain the slight/chance type wording for now.
.SHORT TERM...(Today and Tonight)
ISSUED AT 342 AM CST FRI FEB 28 2014
A compact storm system will try to spread some light rain or
possibly snow to southeast Missouri late this afternoon. The storm
system gets sheared apart tonight as it moves across our region. The
western portions of southeast Missouri have a decent chance of
getting some light precipitation, and if it can saturate the dry
low-levels, which is doubtful, it could briefly change over to snow.
Used the consensus of short term guidance for temperatures through
the day which is a bit cooler than the MAV/MET numbers for highs.
Given the warm temperature forecast, there is no way to support a
mention of snow at this time.
For tonight the lift/saturation is too shallow to activate ice
nuclei, so light rain or drizzle is all that could be expected. Will
have a smattering of mainly slight chance pops through the night as
the disturbance moves southeast across the area, and the low levels
try to saturate with the weak surface front approaching our northern
territories overnight. Temperatures should be safely above freezing
to avoid any freezing rain/drizzle tonight.
Our region has the potential for a significant winter storm from
Saturday night into Monday, with the main threat being ice
accumulation. So much to discuss will try not to go into too much
A cold front will sag slowly southeast across the lower Ohio valley
Saturday into Saturday night. With decent moisture and weak ripples
of energy in the near zonal flow aloft, models are cranking out
precipitation mainly along and north of the boundary. Between
midnight and 6 AM Sunday surface temperatures are expected to fall
to at or below freezing generally over the northwest half of our
CWA, so the accumulation of ice should begin during this period over
On Sunday as the front moves just to the south and east of our CWA
it will allow the shallow sub-freezing air to progress slowly across
more of the area. With models typically not handling shallow arctic
airmasses well, we decided to load in raw model data versus ensemble
data which showed the colder air farther south and east. Throughout
the day Sunday models continue to indicate post frontal
precipitation which should be in the form of ice. During the
afternoon the freezing line is expected to make it completely
through our CWA, so by late afternoon there could be ice
accumulations starting over the southeast half of our CWA as well.
Needless to say, where the freezing line at the surface sets up and
perhaps waffles back and forth a bit will make all the difference
where ice accumulation is concerned. As a weather system lifts
northeast out of the southern plains Sunday night, it will form a
wave on the aforementioned frontal boundary thereby producing an
overrunning scenario consisting of impressive QPF amounts over our
area. During this period all surface temperatures should be below
freezing so ice accumulation is expected to be impressive especially
during the evening causing extremely difficult travel conditions as
well as the potential for power outages. After midnight Sunday night
the colder air above the surface will begin to filter into the area
which should change precipitation over to snow or sleet over all but
the southern Pennyrile region of west Kentucky where it could be
freezing rain or sleet.
As the system pulls away on Monday, wrap around precipitation should
be all snow with only minor additional accumulation. Storm total
snow is expected to range from 1 to 3 inches over the northwest half
of the CWA with less than one inch over the southeast half. Storm
total ice accumulation should be very impressive with ice
accumulation between one half and three quarters of an inch area
.LONG TERM...(Saturday through Thursday)
ISSUED AT 342 AM CST FRI FEB 28 2014
Behind the winter storm system, it will be quite cold throughout the
region through at least Wednesday, as Arctic surface high pressure
settles over the ice/snow enshrouded area. There will be a split
flow aloft through the week, but it should generally be zonal. There
is not a lot of confidence in the handling of disturbances in the
flow. The 00Z GFS and ECMWF each develop a disturbance coming out of
the southern Plains and into the northern Gulf Coast region
Wednesday night and Thursday, but the precipitation shield would
stay to our south/southeast. Any precipitation with a disturbance in
the northern stream should pass to our north Wednesday into
The 00Z GEM is alone in dragging what would be snow across our area
Wednesday and Wednesday night, so will leave the chance pops
throughout the area Wednesday night, with a slight chance in the far
west Wednesday. As I said earlier, confidence is quite low in the
PoP forecast, but it would take quite a system to generate
precipitation in the dry/cold tundra of the Quad State.
As for temperatures, GFS and ECMWF-based guidance seems quite warm.
Do not know if they have swapped to Spring MOS equations, now that
we are about to enter March, or not, but am quite confident they are
too warm. The HPC guidance is much cooler and seems reasonable given
meager sunshine, no significant southerly or southwesterly flow, and
likely snow and ice cover throughout the region. Knocked a few
degrees off the MEX/ECE consensus, but not as far as HPC would
ISSUED AT 559 AM CST FRI FEB 28 2014
A smattering of mid and high clouds will stream across the area
through the day, as southeast winds pick up to near 10kts. A
weakening upper-level disturbance will move through the region
late this afternoon and this evening. At this time, it appears
that it will only result in a lowering of ceilings to the 5-10kft
layer mainly this evening. Overnight, the disturbance will move
out of the area, but low-level moisture will increase ahead of an
Arctic cold front lingering just northwest of the area. This could
lead to MVFR visibilities in DZ/BR and/or MVFR ceilings. Kept the
forecast just above MVFR thresholds for now. Winds overnight
should be light and variable.
IL...WINTER STORM WATCH from late Saturday night through Monday
morning FOR ILZ075>078-080>094.
MO...WINTER STORM WATCH from late Saturday night through Monday
morning FOR MOZ076-086-087-100-107>112-114.
IN...WINTER STORM WATCH from late Saturday night through Monday
morning FOR INZ081-082-085>088.
KY...WINTER STORM WATCH from late Saturday night through Monday
morning FOR KYZ003>005-007-010-014-015-018.