Scientific Forecaster Discussion
fxus63 kpah 282307
Area forecast discussion
National Weather Service Paducah Kentucky
607 PM CDT Fri Apr 28 2017
issued at 607 PM CDT Fri Apr 28 2017
Short term...(tonight through Sunday night)
issued at 126 PM CDT Fri Apr 28 2017
A warm front is lifting north across the region. This front will
be both the immediate and short term focus for convection.
Currently, surface based convective available potential energy were starting to appear in southern
KY and the semo bootheel, or, along/just south of the boundary,
where surface dew points have risen into the mid 60s. North of the
boundary, parcel lift is elevated, with dew points from the mid
50s to low 60s. Helicity values along the boundary are high, but
with scarce surface based instability, and still some capping to
erode, activity on radar has been more isolated to scattered, and
more to our west, where first couple of warnings have been issued.
Will continue to monitor closely as warm front lifts north, and
we warm sector. Latest sels mesoscale discussion outlooks 50 percent probs for watch
box this PM, so they are literally 'watching' as well.
Tonight, better organization/better upper dynamics come into play,
so should see better storm coverage, even in the warm sector. Alot
then depends on where boundary sets up, and there is still some
model difference between across our northern counties, or, to our
north entirely. Either way, activity should be most vibrant along
and in vicinity of boundary, with heaviest rains focused in that
vicinity. Highest qpf thus expected across our north and west,
with least qpf across our south/east, where convective activity
will be most isolated/marginalized.
Saturday, as advertised, looks like a pause, with redevelopment
late Saturday into Saturday night. Sunday still looks active and
as we transition to cold front and it's passage, into Sunday
night, pcpn ending west to east. Continued slight risk Sat PM-night
and sun PM- night as well.
Per collab with lmk, expanded flash flood advisory to the south and east to mesh
with southern in and northcentral KY. Ran for entire event.
Amounts will be highest further south and west, but this will line
up best with ind/lmk.
Long term...(monday through friday)
issued at 231 PM CDT Fri Apr 28 2017
Models Show Low pressure moving from Iowa into the Great Lakes
region on Monday into Monday evening, taking any lingering moisture
northward. Weak high pressure will briefly give US dry conditions
Monday into Tuesday.
Models indicate a warm front lifting north toward our region late
Tuesday into Tuesday night. The European model (ecmwf) and GFS take the warm front
into our far southeast counties midday Wednesday. Based on the
these solutions, showers will quickly spread across the area Tuesday
night, with chances continuing into Thursday. Model show a little
instability making it into our extreme southern counties during the
day Wednesday, and included some slight chances for thunderstorms in
these location. The low associated with the front will push east
of our area on Thursday, so we should see precipitation tapering off
from west to east Thursday night.
A weak upper level disturbance may produce a few showers on Friday,
so included just some slight chances. Temperatures through the work
week will be below seasonal normals, with the warmest day being
Tuesday when highs will reach the upper 60s to lower 70s.
issued at 607 PM CDT Fri Apr 28 2017
Kept the tafs simple. Indicate an increasing chance of convection
by 02z and continuing through the overnight. Will likely have
updates once convection organizes and we can pinpoint where we may
have lower ceilings and visibility due to showers and storms.
Otherwise winds will generally be from the south to southeast near
10 kts, variable speeds, more gusty with convection. The chance
should diminish with a lull the first part of Saturday. We may see
a chance again in the afternoon. But confidence a bit low for 2
now. Will withhold on a mention in the planning portion of the
Illinois...Flash Flood Watch through late Sunday night for ilz075>078-
MO...Flash Flood Watch through late Sunday night for moz076-086-087-
In...Flash Flood Watch through late Sunday night for inz081-082-
Kentucky...Flash Flood Watch through late Sunday night for kyz001>005-014-