Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 122241
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
541 PM CDT MON OCT 12 2015
Issued at 541 PM CDT MON OCT 12 2015
Leading edge of of convective activity associated with cold front
should move out of the WFO PAH County Warning area between 600-615
pm CDT. Some weak looping structures showed up near Grand Rivers
and Rockcastle Kentucky...with isolated cells further to the
northeast near KOWB during the past hour. Some splitting cells
over southern Graves and Calloway County (near Murray, KY at this
time. Evidence of slightly stronger updrafts noted over northeast
Trigg County (north of Cadiz, KY) where MRMS Vertically Integrated
Ice content has been increasing and some evidence of higher dBZ,
greater than 50, showing up near the -20C level at this time in
MRMS Hail fields.
At this time, handling stronger cells with Significant Weather
Advisories (SPS`s) to handle below severe potential hail and
winds. These compliment current broad scale Special Weather
Statement for West Kentucky til 715 pm.
Could see an isolated hail report from elevated convection behind
main line. Sub-severe hail (size unknown) was noted through media
twitter reports near KHSB (Harriburg, IL) late this afternoon,
otherwise main concern will be with the leading line for the next
hour. Rainfall estimates pretty close to dual polarization
rainfall estimates, generally at or below 0.3" inches.
.SHORT TERM...(This evening through Wednesday night)
Issued at 228 PM CDT MON OCT 12 2015
Lower 60 surface dewpoints are about to push northeast out of
northeast Arkansas and the Missouri Bootheel and into west
Kentucky ahead of the cold front. This should lead to better
surface-based instability, which should increase confidence in
scattered convection developing along or just ahead of the cold
front mainly over west Kentucky generally after 4 PM. Will leave
the morning update PoP/Wx grids mostly intact through early
evening. However, did have to add slight chances farther northwest
to account for the showers and storms over the KSTL metro area.
Figure that most of that activity will skirt along the I-64
corridor in the next few hours, before the better convection
develops farther to the south.
All of the convective activity will push southeast of our forecast
area by 02Z, and then it should quickly become clear throughout
the region. There will be modest west/northwest breezes through
the night, so temperatures should not tank much below 50 despite
dewpoints well into the 40s, if not the upper 30s by morning.
For Tuesday and beyond the flow aloft will be rather uniform from
the northwest and surface high pressure will slowly build overhead
by Wednesday afternoon. Look for northwest winds to continue
through Wednesday, with afternoon gusts over the EVV Tri State.
Winds will finally become calm Wednesday night, which should be
our coldest night.
With the dry air overspreading the area tonight and Tuesday, will
play the larger diurnal range through the period. Will lean toward
the warm side of guidance for highs both days. With some wind
tonight and Tuesday night will stay close to consensus for those
lows, but will undercut guidance some for lows Wednesday night,
and that may not be cool enough.
.LONG TERM...(Thursday through Monday)
Issued at 228 PM CDT MON OCT 12 2015
Surface high pressure over the southeast United States Thursday will
slide off the east coast Thursday night. Models show a cold front
sliding across the Ohio/middle Mississippi Valleys Thursday night.
The last couple of runs of the ECMWF have generated 0.01 QPF east of
the Mississippi River between 06z and 12z Friday, while the last
couple of runs of both the GFS and Canadian keep any measurable
precipitation well east of the PAH forecast area. Though a stray
shower may not be out of the question late Thursday night, will
stick with a dry forecast.
The bigger factor with the cold front will be the colder air that
settle into our region behind the front. Canadian high will build
southward, and weekend temperatures will be well below normal. Our
coldest night will Saturday night when the surface high will be
nearly overhead and winds should be very light to calm. Lows will
drop into the middle to upper 30s. Not very concerned about frost
at this point with temp/dew points spread currently forecast to be
about 6 to 9 degrees, but that will be something to monitor through
Models show the high moving off to our east Sunday into Sunday
night, and the pressure gradient tightening up. Breezy south winds
will start a return of warmer air and some low level moisture on
Monday. After highs in the 60s over the weekend, Monday highs will
climb back to near normal readings around 70 degrees.
Issued at 1155 AM CDT MON OCT 12 2015
Gusty southwest winds will veer to due west as a cold front
approaches this afternoon. The latest guidance indicates that
scattered showers and thunderstorms will develop near the cold
front beginning around 21Z in the vicinity of KEVV and KPAH. The
convection will move quickly eastward and will have the greatest
chance to impact KOWB. Any convection should be southeast of the
terminals by 00Z. West winds and dry advection should prevent any
fog overnight, so the forecast is VFR outside of TS. Northwest
winds will pick up with mixing Tuesday morning.