Area Forecast Discussion
Issued by NWS Wilmington, OH-- Highlight Changed Discussion --
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FXUS61 KILN 300623
Area Forecast Discussion
National Weather Service Wilmington OH
123 AM EST Wed Nov 30 2016
Low pressure will approach the area from the south tonight allowing
for showers to develop near central Tennessee and Kentucky. The
showers and isolated thunder will then push northeast to the
middle Ohio Valley late tonight into Wednesday morning. Most of
the rain will fall southeast of the I-71 corridor and then colder
air will enter in Wednesday evening behind a cold front.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Low pressure near south central Tennessee will ripple northeast to
the middle Ohio Valley by Wednesday morning. This feature will be
associated with moist ascent in the form of a LLJ. Highest chance
for precipitation will be across south central Ohio and northeast
Kentucky due to the low and its associated LLJ. The area between
light precipitation and heavier precipitation will be near I-71
corridor. This is where a brief period of 850 mb to 700 mb
frontogenesis develops. This region includes Cincinnati,
Wilmington, and Columbus with the likely PoPs transitioning over
to categorical as one heads east/southeast. Finally, west central
Ohio, the Whitewater, and Miami Valleys will have the lowest
chance with very light precipitation possible. Precipitation will
be in form of showers. There may even be enough instability for a
rumble of thunder, mainly over south central Ohio and northeast
As for temperatures, they will fluctuate a little with some areas
warming due to southerly flow and others cooling due to evaporative
cooling. Overall, lower to mid 50s will be common by sunrise
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
Wednesday after the sunrise the low will be exiting the area
towards the northeast taking most of the rain with it. Wednesday
afternoon there might be some brief breaks in the clouds before
an upper level low in Minnesota begins to push east. As this
happens a band of PVA will push through the area. A surface cold
front will then push through with the PVA. The cold front will
enter our western zones starting around 18z and then clear our
eastern zones around 21z. Some high res models are hinting at some
showers with isolated thunder possible with the front. Looking at
forecast soundings there is some weak instability but confidence
remains low on if there will be any instability at all.
As the front pushes through the area Wednesday afternoon winds
will begin to pick up and with gusts of 25 to 30 kts possible.
Wednesday night into Thursday winds will stay gusty at times due
to CAA and a tight pressure gradient. Forecast soundings for
Thursday also keep 850mb saturated with clouds likely staying
around all day Thursday and into Friday. The NAM has the low layer
moisture staying around into Friday but has some partial clearing
across our southwest. 850 mb temperatures fall to around six degrees
below zero Thursday into Friday and with clouds around high
temperatures will likely struggle to get out of the lower 40s.
Have gone ahead and lowered high temperatures a bit Thursday into
Friday. It also should be noted that Friday morning the GFS is
saturating the low layers just enough to possibly have some
flurries. For now have left the mention out as the GFS appears to
be a bit to aggressive with the low layer moisture.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A quasi-zonal flow pattern will be in place at the start of the
weekend as our area will be in between a trough over eastern Canada
and a developing upper level trough/low over the southwestern United
States. Some weak pieces of energy will move quickly east across the
southern Great Lakes Friday night through Saturday night. While it
will be tough to rule out some spotty shower activity, the chance
appears low enough at this point to go with a dry forecast through
the first half of the weekend. Highs on Saturday will be at or a
little below normal, ranging from the upper 30s in the northwest to
the lower and mid 40s in the southeast.
There is quite a bit of model uncertainty as we head into next week
as both the 12Z GFS and the 12Z ECMWF have trended weaker and
farther south with the initial energy ejecting out of the trough
over the southwestern United States. The ECMWF is trying to phase
some of this energy with a short wave pushing east across the Great
Lakes Sunday into Sunday night while the GFS does not and keeps our
area mainly dry. Will therefore go ahead and trim back pops a bit
and just allow for some lower chances for primarily Sunday into
Sunday evening. Depending on the exact timing, if any pcpn starts
early enough on Sunday, it could be in the form of snow, before
transitioning over to rain as we warm up in the afternoon. Expect
highs on Sunday in the low to mid 40s.
There is also some disagreement with how fast the main energy will
eject northeast out of the western trough toward the end of the long
term period. The GFS is weaker and somewhat faster with this
compared to the ECMWF. Will go ahead and trend toward a blend and
allow for chance pops to spread in from the southwest Monday night
into Tuesday. Low level thermal fields are generally warm enough to
support all rain with this event. Highs will trend a little above
normal through the end of the period with highs by Tuesday ranging
from the mid 40s north to the lower 50s south.
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --First surge of pcpn is slipping south and east of the tafs.
However as low pressure advances northeast up the edge of the
Appalachians additional rain will develop along a deformation
axis. Models swing this pcpn back across the wrn tafs between
08-12z. Tthe pcpn isn`t expected to be heavy and shouldn`t cause
a deep reduction in visibilities. Ceilings are forecast to lower
to MVFR this morning as low level moisture is pulled into the
region ahead of the low.
After 12Z, a cdfnt will move through the region. Models suggest a
least a chance of showers with this frontal boundary. Winds will
become a little gusty behind frontal passage. Conditions will also
improve back to VFR behind the front.
CAA tonight will bring increasing stratocumulus clouds.
OUTLOOK...MVFR ceilings possible through Friday. MVFR ceilings and
visibilities possible Sunday.
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