Area Forecast Discussion
Issued by NWS Wilmington, OH-- Highlight Changed Discussion --
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FXUS61 KILN 280010
Area Forecast Discussion
National Weather Service Wilmington OH
710 PM EST Sun Nov 27 2016
High pressure and a dry airmass will move east tonight. Moisture
will increase Monday as low pressure travels to Minnesota, with
widespread showers expected Monday night. Drier weather will
follow for Tuesday in the relatively dry southerly flow behind the
low. More showers will be likely Wednesday when a large swath of
moisture and forcing is forecast to move up along the Appalachian
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Surface high pressure centered near the Carolina coast will keep
dry weather over the ILN area tonight. Mid and high clouds will
increase ahead of vigorous low pressure advancing toward
Minnesota. This will allow overnight lows in the mid 30s
northeast to around 40 southwest, a bit above normal.
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Moisture will be increasing well ahead of the low on Monday.
Clouds will thicken and lower, and showers may develop by
afternoon, mainly over western locations closer to the low.
For Monday night, the initial low center in the vicinity of western
Minnesota will fill in, while another low develops and moves to
Lake Michigan. The ILN area will be under a very strong low level
jet ahead of this system, resulting in a concentrated plume of
moisture being advected from the southwest. Showers will develop
in convergence and lift under the jet. Kept categorical pops as
measurable rain is nearly certain. Rainfall averaging 1 inch is
indicated by model QPF, breaking the dry spell. Decided to keep
thunder out of the forecast in a regime containing limited
instability. Breezy conditions are expected, with gusts around 30
mph common, and higher gusts likely with heavy showers.
Tuesday will feature drier conditions as the band of showers moves
quickly east. Showers may develop again Tuesday night in a swath of
moisture and forcing arriving on a southwest flow aloft.
Temperatures will exhibit a warming trend in the persistent
southerly flow. Highs are forecast to be in the 50s Monday, rising
to the 60s most locations on Tuesday.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
On Wednesday morning, a stacked area of low pressure will be located
over Minnesota, with a shortwave trough developing to its south from
Iowa to Oklahoma. The overall pattern ahead of this feature will be
amplifying, with deep-layer southwesterly flow (and a very fast
upper jet) running from Texas to the eastern Great Lakes. The Ohio
Valley will be in this regime, which will see an increase in forcing
through Tuesday night into Wednesday, especially just to the
southeast of the forecast area. Several elements are coming
together, with upper support from the jet, mid-level frontogenesis,
and some convergence along an approaching surface cold front. Models
have converged on the faster ECMWF solution, bringing the highest
chances for precipitation through the region in the 12Z-21Z time
frame. With good agreement on timing and a slight northwestward
shift in position from previous runs, PoPs have been increased --
with room to increase even further in future forecasts. Hazardous
weather is unlikely, but there is some potential for a decent amount
of rainfall in the southern and southeastern sections of the CWA,
which could be beneficial.
Though Wednesday will be relatively mild, with temperatures above
normal, cooler conditions are expected once the cold front passes
through late in the day. However, with boundary layer flow only
turning to the WSW behind the front, cold advection is not expected
to be particularly strong. This will set up several days with
temperatures slightly below normal, but not significantly so.
As the large upper low elongates from west-to-east while moving
across Canada, cool temperatures aloft will help lead to mostly
cloudy conditions through the end of the week. As the coolest
850mb/700mb air rotates across the southern Great Lakes on Friday
evening / Saturday morning, a few light rain or snow showers could
be possible near or north of Interstate 70. Generally zonal flow is
expected heading into the weekend, with a slight upward adjustment
in temperatures, but uncertainty in the forecast increases
significantly beyond Saturday.
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --High pressure will move off the Carolina coast by Monday morning
as deepening low pressure pivots northward across the central and
northern Plains. For our region, considerable mid and high level
clouds will increase/thicken overnight. A deeper plume of moisture
along with warm/moist ascent will bring some showers near the
western terminals toward 12Z.
On Monday, as low pressure occludes over the northern Plains,
embedded energy rotating around the mid level circulation will
eject from the southern plains to the lower Ohio Valley through
the day. As this occurs, deeper moisture and eventually widespread
showers will gradually pivot east/northeast into our area. The
surface pressure gradient will tighten through the period along
with a developing 70-80 knot 850 mb low level jet. Conditions will
lower to MVFR from west to east as showers become moderate to
locally heavy and saturation allows ceilings to drop. The
increasing low level jet will bring winds at 2000 feet into the 55
to 65 knot range toward 00Z, so non convective LLWS was added to
the western terminals for this likely occurrence. Surface winds
will increase into the 15 to 20 knot range with gusts at least in
the lower 30 knots possible by evening.
For Monday night, embedded energy will perturb another area of low
pressure to our northwest while an occluded front moves through
our the region. Widespread showers will occur ahead of the front
along with continuing MVFR conditions. Precipitation is expected
to quickly come to an end from west to east late Monday night into
Tuesday morning along with decreasing winds and improving
OUTLOOK...MVFR ceilings and visibilities with showers expected
Monday night into early Tuesday morning, along with the potential
for wind gusts in the lower 30 knots. MVFR ceilings and
visibilities possible Wednesday into Wednesday night.
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