Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
1038 am EDT Tuesday Jul 7 2015
a cold front will push into the region today...bringing
widespread showers and thunderstorms. As the front becomes nearly
stationary across Ohio on Wednesday and Thursday...additional
rounds of showers and thunderstorms are expected. Somewhat drier
conditions will be possible Friday under weak high pressure.
Near term /through tonight/...
cold front extending from Southern Lower Michigan through northern in back
into central Illinois at this time. Still a fairly slow progression of the
frontal boundary. Conventional models handling boundary
progression failry well...with timing of the GFS preferred...but
of course the non-cam models poorly handling the resulting
convection. Have updated forecast based on a rap/hrrr combination.
These focus the precipitation along/ahead of the frontal
boundary...as well as in southern forecast area where best moisture
transport and ll convergence resides. Have increased precipitation
chances as well as included mention of heavy rain possible...and
with efficient rainfall across southern Indiana not showing much
lightning...heavy rain occurring with showers and not just
embedded thunderstorms. Best coverage would generally be in the
18-00z timeframe nearly along/northwest of I-71 corridor...then focus
shifting southeast overnight. While a marginal threat exists for
severe storms under moderate instability...and cant rule out a
possible wet microburst type storm...main threat will be heavy
rain potential with with the slow moving system...warm cloud
depths of 4000m or more and efficient moisture transport.
With increased low level clouds...have tweaked daytime highs a bit
downward as well.
Short term /Wednesday/...
a potent wave of low pressure traveling along the front will
provide a period of enhanced lift on Wednesday. Showers and
thunderstorms will be likely in the persistently moist regime.
Convection may diminish later Wednesday afternoon when the wave is
forecast to move east.
Another ripple of low pressure moving along the front is indicated
for Thursday. Though there is less certainty with respect to the
effects of the low...there will be a very good chance for more
showers and thunderstorms. The repeated rounds of convection will
probably result in high water and localized flooding. Will
continue mention of possible flooding in severe weather potential statement.
Below normal temperatures are expected under a regime of clouds...
precipitation and occasional cold advection. Highs on Wednesday are
forecast to range from about 70 north to 80 south. The track of
the wave of low pressure on Thursday should allow somewhat higher
temperatures varying from the middle 70s north to low 80s south.
Long term /Wednesday night through Monday/...
upper high over the southeast US will strengthen as it starts to
retrograde. Forecast area will be on the northern periphery of the
high which will evolve into northwest flow over the weekend.
Frontal boundary will become ill-defined but guidance is
suggesting that some vestige of it could remain in the vicinity
which would serve as a focus for convection...especially as weak
disturbances move through the upper flow.
An upper trough will develop into the Great Lakes on Monday. This
will push a low into the region and increase the chance of rain.
Lows will be at or above normal through the period. Highs will start
out below normal but then warm above normal over the weekend only to
start dropping back on Monday.
Aviation /14z Tuesday through Saturday/...
moist southwesterly flow will continue to lead to an increase in clouds
this morning. Some of these clouds will result in MVFR conditions
for brief periods. These clouds have inhibited widespread fog
development. MVFR visibility restrictions will be limited to
Kiln and kcmh/klck early.
A cold front will approach the area today and push down into
Ohio tonight. Expect moderate instability to develop during the afternoon.
Scattered thunderstorms will develop ahead of T his front associated
with low level jet. Best coverage of these pre-frontal storms will
occur over the SW taf sites.
Have a mention of thunderstorms in the vicinity to account for early thunderstorms especially
at kcvg/kluk. Have tempo group at each taf site for the most
favorable time period for convection...primarily during the late
afternoon hours. As the front pushes into the region expect
widespread precipitation coverage. Have prevailing rain with thunderstorms in the vicinity
this evening and MVFR ceilings. IFR ceilings are not out of the question
late tonight behind the front but at this time have elected to
keep forecast in MVFR category due to uncertainty.
Winds from the SW will increase today with gusts up to 23 kts.
Outlook...thunderstorms possible Wednesday through Friday.