Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 260557

Area Forecast Discussion
National Weather Service Wilmington OH
157 AM EDT Wed Oct 26 2016

High pressure will keep dry weather over the region through
tomorrow morning. Low pressure traveling across northern Ohio
will bring showers Wednesday night into Thursday morning. High
pressure and a dry airmass will return for Thursday night and


The main focus for the update this evening was to adjust sky grids
based on current satellite trends, and to assess the impact that
the cloud cover is having on temperatures. The thickest cloud
cover is currently stretching across the central / north-central
sections of the CWA, running from north of Indianapolis through
Chillicothe. Temperatures in this area are still in the upper 40s
to near 50, and may not fall quickly overnight, especially with
light northeasterly flow failing to go calm. Dewpoints are still
fairly dry -- mid 30s through most of the CWA, and closer to 40 in
the southwest. This at least provides the potential for
temperatures to fall enough to support frost, though the winds and
clouds may make it difficult. No confidence in any decision to
expand the frost advisory, so it will remain in place, with the
best chance for areas of frost in the extreme northern /
northeastern sections of the ILN CWA.

Previous discussion >
High level clouds continue across the central part of the CWA this
afternoon and are forecasted to remain over the area for the
greater part of the night. At the same time, surface high
pressure will slowly pull east. Given the high clouds overhead
this would in general inhibit optimal radiational cooling but with
winds mostly light across the eastern zones frost will still be
possible. Have gone ahead and issued a frost advisory for our
eastern zones to account for this.


During the day Wednesday a shortwave will push east across the
midwest with surface high pressure eroding from the area. In
response to the shortwave a surface low pressure will form. A warm
front will then pull north across the area. As this happens highs
will warm into the mid to upper 60s across the southwest with
highs in the upper 50s across the far north. Most of the area will
remain dry Wednesday though as the shortwave remains just far
enough west.

Wednesday night into Thursday morning ILN will move into the
divergent region of the trough axis with most of the PVA remaining
north of the area. Surface low pressure will then track just north
of the area Thursday morning. PWATs ahead of the system rise to
around 1.10" (~1.05" on GFS and 1.20" on NAM) with both NAM and
GFS soundings never fully saturating. Instability will also be
hard to come by as the event will occur at night. The GFS has
almost no instability at all (surface or elevated) while the NAM
does have some elevated instability (100 - 300 J/kg of CAPE).
Shear values ahead of the low are impressive. Both the GFS and NAM
forecast soundings are showing SFC-1km shear values approaching 40
kts. SFC-1km SRH is also forecasted to be around 400 m2/s2. Due to
the lack of instability though have kept only slight chance
thunder in the grids. A surface cold front will then push through
the forecast area Thursday morning ushering in cooler and drier
conditions. The cold front will be weak though and only push
temperatures back down to normal values for this time of year.


High pressure will be centered over the area Friday morning.  This
will allow for dry conditions and light winds.  The area of high
pressure will push off to the east Friday into Friday night.

Winds will pick up on Saturday out of the southwest.  Wind gusts of
30 to 35 mph will be possible.  These warm winds out of the
southwest will bring much above normal temperatures to the area.
High temperatures are expected to be around 15 degrees above normal,
however still around 5 to 7 degrees below record at this time.  The
forecast high on Saturday at CMH is 75, record 80, normal 60.  The
forecast high on Saturday at CVG is 78, record 83, normal 62.  The
forecast high on Saturday at DAY is 75, record 82, and normal 59.

A frontal boundary will work through the region on Sunday. Moisture
is limited with this feature and therefore went dry to chance for
precipitation chances.  The best chance of some light shower
activity will be across northeastern portions of the forecast area
around CMH.

High pressure will then work into the area Sunday night into Monday.
There is not a significant precipitation signal for the end of the
long term and therefore went with dry conditions.


A SCT to BKN deck of mid and high level clouds will persist
through the remainder of the overnight period for the TAF sites.
With these clouds in place and the flow unlikely to go completely
calm, fog potential will be quite limited, even for KLUK.

Scattered -SHRA across eastern IL will continue to work east
through the overnight and early morning hours. Hi-res suite of
models show some of this activity holding together into west-
central Ohio towards sunrise. While the ARW/NMM/RAP indicate just
some spotty very light rain showers for KDAY around 12z, the most
recent several runs of the HRRR have been a bit more robust in
sustaining the activity through west-central Ohio. Do think the
HRRR is being too aggressive, but decided to go with a VCSH for
just KDAY during the morning hours to account for this potential.

SCT/BKN mid and high level clouds will stick around through the
day Wednesday as a sfc low pressure approaches the region from the
west towards the end of the TAF period. Latest model runs,
including high-res solutions, have backed off on the onset of
scattered -SHRA working into western terminals. Do think scattered
showers will approach KDAY around/shortly after 03z Thursday. Have
left out mention of precip for now at all other sites except for
30-hr KCVG as activity will likely move through after 06z

Winds will veer more easterly and then southeasterly through the
day. Winds will be 10-15 kts, with the potential for a few gusts
to 18 kts during the afternoon, especially for KDAY. Towards the
very end of the period, winds will go more southwesterly for
western terminals as the cold front approaches Thursday morning.

OUTLOOK...MVFR ceilings and visibilities are possible from
Wednesday night through Friday morning.


OH...Frost Advisory until 9 AM EDT this morning for OHZ046-056-064-


NEAR TERM...Haines/Hatzos
AVIATION...KC is the U.S. government's official web portal to all federal, state and local government web resources and services.