FXUS61 KILN 270707
AFDILN
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
307 AM EDT Sat Jul 27 2024
.SYNOPSIS...
High pressure and dry conditions will be in place through
tonight. An unsettled weather pattern will develop for Sunday
and remain in place through the week, with several episodes of
showers and storms expected through the workweek. Seasonably
warm and humid conditions will prevail through the week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Sfc high pressure centered to the NE of the region will continue
to slowly drift away from the OH Vly through the near term
period. This being said, LL return flow won`t really
become fully established locally until late tonight, so the
unusually dry airmass will remain parked across the area until
such point that the light southerly flow begins to advect it
away from the OH Vly Sunday morning. This will translate to
abundant sunshine through the day today, with just a few cirrus
from time to time.
Temps tonight will dip into the upper 50s, with some mid 50s
likely in rural/sheltered areas by daybreak. With dry LL air
still in place, the temp rebound will be swift and substantial
into this afternoon as temps nudge into the upper 80s to around
90 degrees as the airmass begins to subtly moderate. Diurnal
swings will be on the order of about 30 degrees today
-- something that`s not too common for this time of the year.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Tranquil conditions continue tonight... although a weather
pattern shift will be well underway as the aforementioned sfc
high continues to drift further away from the region. On the
backside, LL flow will become increasingly southerly once again
into Sunday morning. This will allow for a rather abrupt and
aggressive return of higher dewpoints, which will move into the
Tri-State and SE IN/N KY by early afternoon.
But before we talk about the return of rain/storm chances Sunday
afternoon, mid/high cloud cover will already be on the increase
across the W/SW tonight. Lows tonight will dip into the lower
to mid 60s area-wide, with some upper 60s possible in parts of N
KY and SE IN where cloud cover will be thickest into the
predawn hours Sunday.
After daybreak Sunday, robust moisture advection will be
underway, initially to our SW, before this richer LL moisture
quickly spreads to the N into the local area by early afternoon.
The dewpoint rise in the Tri-State from late Sunday morning
into mid afternoon will be somewhat abrupt... jumping perhaps
12-15 degrees (from the upper 50s to lower 70s) in just a few
hours from 15z to 21z. And corresponding with this jump in LL
moisture content will be the progression of a midlevel S/W N
through the mid MS Rvr Vly, with enough forcing amidst the
increasingly unstable environment to promote some ISO/SCT
convection in N KY before coverage increases late in the day
from the SW. SCT to numerous SHRA/TSRA are expected for the SW
1/3 or so of the ILN FA toward sunset Sunday evening, with drier
air hanging on as best it can in central OH... keeping the NE
2/3 of the area mainly dry through the short term period. As
such, there will be quite a gradient in high temps on Sunday as
the SW remains more draped in cloud cover/pcpn chances
(especially late afternoon) with highs ranging from the lower
80s near the Tri-State to the lower 90s in the clearer/pcpn-free
locales in central OH.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Mid-level ridge continues to break down Sunday night as height falls
occur ahead of the upstream trough. Expect ongoing showers,
downpours, to continue into the evening hours even as daytime
heating decreases. Abundant moisture and broad-scale ascent
associated with the trough suggest the potential for locally heavy
rainfall overnight into Monday morning. There is still some question
as to which locations would have the best chance for observing this
so will exclude mention in the HWO for now, especially with
locations observing moderate to severe drought.
Additional shortwave energy will move through the trough Monday
afternoon with diurnally driven activity the main focus. Deep
moisture lingers into the evening and overnight, so will need to be
mindful for the potential of locally heavy rainfall once again.
The period Tuesday through Thursday is a bit different as the region
sits within the northwesterly flow of the trough slowly moving
eastward through the Great Lakes. An EML supplies steeper mid-level
lapse rates, opening up opportunities for more abundant CAPE across
the lower Midwest. Each one of these days presents the scenario
where organized convection could evolve into the area, over the
area, or west of the area... These days would also provide the best
chance for severe weather, however given the lower confidence, will
maintain low probability wording in the HWO.
On Friday, another trough is expected to exit the northern Plains,
moving southward toward the lower Midwest. In the least, this keeps
the area within a favorable area for additional showers and
thunderstorms. While the EML breaks down later in the week, can`t
completely rule out another opportunity for severe weather to close
the work week.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
Aside from some river valley BR (leading to MVFR or IFR VSBYs) at
KLUK once again through daybreak, VFR conditions will be
maintained through the period area-wide. And aside from some
cirrus from time-to-time, mainly across southern parts of the
area, clear skies will prevail as well.
Light NE flow around 5kts will become more easterly toward the
end of the period.
OUTLOOK...Thunderstorms are possible Sunday through Wednesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...KC
LONG TERM...McGinnis
AVIATION...KC
