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NWS Wilmington, OH Office (ILN)


Area Forecast Discussion/SKEW-T

          FXUS61 KILN 180542
          AFDILN
          
          AREA FORECAST DISCUSSION
          National Weather Service Wilmington OH
          142 AM EDT Fri Jun 18 2021
          
          .SYNOPSIS...
          A decaying system will be approaching late in the overnight and
          into the early morning hours on Friday. Severe thunderstorms
          will develop during the late afternoon and into the evening
          hours on Friday. Heavy rainfall will also be possible.
          Thunderstorm activity and the potential for severe weather will
          again be possible on Saturday as the boundary remains in place
          across the region.
          
          &&
          
          .NEAR TERM /UNTIL 6 AM THIS MORNING/...
          Some storms firing in west central IN/east central IL ahead of
          the line of decaying showers over nrn IL/srn LMich. Took this
          and a few very minor returns over nw IN and blended them into
          the 12z forecast to account for movement, but no models were
          showing any kind of initiation in this section at all tonight,
          so this appears to be a wildcard in play that will likely affect
          the forecast updates tonight, especially if the CAMs take a
          while to see this and adjust.
          
          Low temperatures overnight are expected to drop down into the
          middle 50s to the middle 60s.
          
          &&
          
          .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
          An active weather pattern will be in place for Friday into
          Friday night. A decaying MCS will continue to move into northern
          portions of the region during the morning hours. There are some
          model solutions that bring this feature further south and this
          would have implications for afternoon placement of convective
          development. At this point in time have a slight chance to
          chance of precipitation for locations generally north of the
          Ohio River with likely precipitation generally north of
          Interstate 70. This feature will then likely lay out a boundary
          for convective development during the late afternoon and into
          the evening hours. Winds will pick up for the afternoon hours
          and have wind gusts upwards of around 25 to 30 mph outside of
          thunderstorms.
          
          There are some concerning signals for a higher end damaging wind
          event late Friday afternoon into Friday night. CIPS analogs
          also are supportive of this and SPC has a large portion of the
          region in an enhanced risk. Given shear profiles there is also
          at least some tornadic and hail potential as well. Added severe
          wording into the forecast
          
          Friday night the flow becomes more west-east oriented. With this
          flow orientation there will be flooding concerns as well. A
          flood watch will be needed in the future, however held off for
          now to try to fine tune where the axis of heaviest rainfall will
          be.
          
          &&
          
          .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
          Long term period begins with potential storm complex in the
          south as the upper energy heads east along a mostly stationary
          front. Guidance varies as to how long the convection persists,
          with the 3-km NAM on the drier side and the HRRR keeping
          convection going until it exits into southeast Ohio late
          Saturday morning.
          
          While warm muggy conditions continue Saturday into Sunday, forcing
          looks to be rather weak as the frontal boundary dissipates. Expect
          PoPs to decrease considerably during this time with isolated diurnal
          convection remaining in the grids due to conditional instability.
          High temperatures will peak in the mid to upper 80s each day, with
          lows in the upper 60s.
          
          For Monday, a stronger, more progressive cold front dives southeast
          through the region. Uncertainty is high as far as timing the front.
          ECMWF and its ensemble are slower, with FROPA occurring Tuesday
          morning, and the GFS system quicker with FROPA on Monday evening.
          Uncertainty is amplified by the slow progression of tropical
          remnants moving through the southeast United States Sunday into
          Monday. Despite uncertainty, there is certainly some concern about
          strong to severe storms firing along and ahead of the front
          beginning Monday afternoon into the evening.
          
          Behind the front, decreasing clouds and cooler, drier air arrives
          with surface high pressure starting to build in after noon on
          Tuesday. In fact, model blend has dewpoints dropping into the upper
          40s to lower 50s Tuesday night and Wednesday. Highs stay in the low
          to mid 70s.
          
          The high shifts to the east on Thursday with max temperatures
          returning to near 80.
          
          &&
          
          .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
          Showers and thunderstorms moving into the southern Great Lakes
          early this morning are forecast to gradually weaken through the
          morning hours as they move into northern Ohio. Convective
          allowing models are generally keeping pcpn associated with this
          initial batch of pcpn north of the northern TAF sites. The
          airmass is then forecast to destabilize through the afternoon
          with a boundary laying out west to east across the region. This
          will serve as a focus for additional shower and thunderstorm
          development later this afternoon and into this evening. There
          is still some uncertainty with the exact location of this so
          will generally just allow for prevailing showers with a VCTS to
          sag south across the TAF sites starting from late this
          afternoon and then persisting into tonight. Some of the storms
          will be capable of producing wind gusts in excess of 50 knots
          late this afternoon into this evening. Locally heavy rainfall
          and reduced visibilities can also be expected at times with the
          storms.
          
          .OUTLOOK...Thunderstorms are possible through Saturday and again
          on Monday.
          
          &&
          
          .ILN WATCHES/WARNINGS/ADVISORIES...
          OH...None.
          KY...None.
          IN...None.
          
          &&
          
          $$
          SYNOPSIS...Novak
          NEAR TERM...Franks
          SHORT TERM...Novak
          LONG TERM...Hogue
          AVIATION...JGL
          
          
Skew-T

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