Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/26/20
Area Forecast Discussion
National Weather Service Louisville KY
925 PM EDT Thu Jun 25 2020
.Forecast Update...
Issued at 925 PM EDT Thu Jun 25 2020
A mainly clear and pleasant night is on tap for the Ohio Valley,
with dewpoints in the mid/upper 50s allowing us to cool off just a
bit. Light S-SW breezes will stay up just enough to keep the
overnight temps from touching the dewpoint, and hold off any fog
formation. No changes to the previous forecast, other than to
freshen the hourly trends in hi-res products.
&&
.Short Term...(This evening through Friday)
Issued at 305 PM EDT Thu Jun 25 2020
Current GOES-16 satellite shows a field of diurnal cumulus over the
forecast area of southern Indiana and central KY as KY Mesonet sites
are showing temperatures as of 1730Z in the low 80s with light winds
predominantly out of the WSW.
As the upper level trough axis that extends N-S across the Ohio
Valley exits to our east, ridging aloft will move in from the west
resulting in continued dry conditions with clearing skies overnight
and redevelopment of diurnal cumulus Friday late morning/early
afternoon. As previously mentioned in this morning`s update, a few
CAMs have hinted at isolated pop-up showers potentially crossing the
northern half of the CWA this afternoon. But model soundings and
AMDAR profiles out of SDF show a warm, stable layer aloft at around
700mb that should severely limit any showers from developing.
Clear skies overnight will likely result in some patchy river valley
fog for Friday morning that will burn off shortly after sunset.
Morning min temps in the low to mid 60s will increase into the upper
80s with some of our hotter spots hitting 90 as increased SW flow
brings in warmer air. Expect to see dew points on the rise as well,
reaching into the mid to upper 60s by Friday afternoon. A quasi-
stationary boundary to our south looks to meander northward Friday
placing much of central KY on the warm side of the boundary. PWATs
will increase to around 1.50 inches by Friday afternoon, but
soundings show pretty weak mid level lapse rates. Have decided to
add a slight chance of showers and storms mainly south of the
Parkways and across southern Indiana for Friday afternoon, but
expect most locations to remain dry.
.Long Term...(Friday night through Thursday)
Issued at 310 PM EDT Thu Jun 25 2020
Friday Night through Sunday Night...
Upper level flow by Friday evening will generally be zonal across
the Ohio Valley. Moving into the weekend, a weak frontal boundary
is forecast to drop into the region and then eventually stall out. A
few mid-level disturbances are then forecast to roll through the
region bringing decent chances of precipitation to the region.
Sensible weather will feature a mainly dry Friday evening, but we
may see a few storms push through southern KY early Saturday
morning. Some additional scattered convection will be possible
Saturday afternoon with highs in the low-mid 80s. There is a
pretty good signal within the guidance for a mid-level vorticity
maximum to roll through the region late Saturday and Sunday. Timing
this thing through the region is still problematic, but this feature
alone will be enough to bring widespread showers and storms to the
region from late Saturday night through Sunday night. Some strong
storms will be possible, but that will be dependent on stability
which could hinge on convective cloud debris and the timing on when
the wave passes through. Nonetheless, any storm will be capable of
producing heavy rainfall, gusty winds, and lightning. Lows Saturday
night will be mild with readings in the upper 60s to the lower 70s.
Highs on Sunday will likely be in the low 80s once again. Lows
Sunday night will be in the upper 60s to the lower 70s.
Monday through Thursday...
Moving into next week, the models suggest a very blocky pattern
across the CONUS, which has been seen quite a bit over the last
several months. The upper air pattern looks to feature deep closed
lows over the western US and in the northeastern US. In between
these closed lows, an upper level ridge axis looks to be centered
from Texas northeastward into the Great Lakes region. The ridge
looks to develop a bit further as we head through the week, with the
ridge axis remaining west of the Ohio Valley. A few vort lobes
rotating around the western portion of the NE US closed low may
continue bring a chance of storms to the region in the Monday and
Tuesday time frame. By mid-late week, the ridge axis may develop a
little more to the east which may bring slightly drier conditions to
the region by late Wednesday into Thursday. While the forecast will
feature mid-high values of PoP through the period, we do not believe
the week will be a washout by any means, but a typical pattern of
mainly afternoon/eve storm threats will likely be seen. Highs
Monday and Tuesday should warm into the lower-mid 80s with readings
increasing slightly as we head into Wed/Thu. For now, plan on
capping things off in the 83-88 degree range for Wed/Thu, but if the
drier Euro signal ends up verifying, then highs in the upper 80s to
near 90 will be possible.
&&
.Aviation...(00Z TAF Issuance)
Issued at 725 PM EDT Thu Jun 25 2020
VFR conditions will persist with mainly scattered diurnal cu and no
restrictions to vis, leaving us with just a wind forecast. WSW winds
initially should go light and variable around sunset. Return flow
starts to set up on Friday, so will carry light SW winds by mid-
morning, but increasing in the afternoon with prevailing gusts just
over 20 kt, and a few 25 kt peaks in play. Could pop off a stray
afternoon shower or storm, but it`s a low enough probability at this
point not to include it in the TAFs.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...RAS
Short Term...CG
Long Term...MJ
Aviation...RAS