Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
441 am EDT Monday Jul 6 2015
a disturbance lifting northeast through the upper Ohio Valley
will bring a few showers and perhaps a thunderstorm to eastern
areas today. A cold front will push into the region from the
northwest on Tuesday and Tuesday night...bringing widespread
showers and storms. The front will remain in the area through the
end of the week continuing the chance of showers and thunderstorms.
Near term /until 6 PM this evening/...
upper level low which has been drifting slowly north-northeast into eastern Kentucky
will open up and lift out across upper Ohio Valley today. This feature
will keep low chance probability of precipitation across the east today. Expect a more clouds
in the east with a fair amount of sunshine west. Temperatures
will continue to slowly warm with highs today ranging from the
lower 80s far east to the middle/upper 80s west.
Short term /6 PM this evening through Wednesday/...
with upper low opening up and lifting out to the NE this evening...
iln/S forecast area will be between systems tonight. So will end any
lingering probability of precipitation in the far east early and allow for a dry period
overnight. Clouds and increase in moisture will keep temperatures
mild with lows tonight in the middle/upper 60s.
Numerical model solutions generally similar with middle level trough sweeping
across the Great Lakes Tuesday/Tuesday night and associated surface front
pushing into iln/S forecast area Tuesday night.
Expect the front to push into extreme Northwest Ohio by Tuesday evening.
Axis of low level convergence develops ahead of this front
associated with 35-40 knots 800 mb jet. NAM continues to show typical bias
with convective available potential energy over 3000 j/kg due to widespread surface dew point/S of 75 or more.
GFS instability looks more reasonable with blyr convective available potential energy values around 1500
j/kg in a moist environment.
Precipitable water/S increase to 2 to 2.25 inches Tuesday afternoon into Tuesday evening.
With moist soundings and warm middle levels...do not expect widespread
severe weather but isolated stronger storms could produce damaging
winds. Will continue to mention this threat...along with the
potential for heavy rain in the severe weather potential statement product.
Will continue to ramp probability of precipitation up to categorical across northwest by late Tuesday
afternoon into Tuesday evening and then continue likely probability of precipitation overnight Tuesday.
With the main push of westerlies across the Great Lakes with front
stalling out east-west just north of the Ohio River Wednesday. Will
continue chance probability of precipitation with the highest probability of precipitation across southern Ohio closer
to the frontal boundary as next low develops in the plains.
Temperature wise...temperatures will be close to normal Tuesday with
highs from near 80 northwest to the middle 80s southeast. Lows Tuesday night will
range from the lower 60s northwest to the upper 60s southeast. Highs Wednesday
will be suppressed...ranging from the middle 70s northwest to the Lower/Middle
Long term /Wednesday night through Sunday/...
disturbances moving through nearly zonal flow along with a quasi-
stationary frontal boundary will result in periods of showers and
thunderstorms into Thursday. Clouds and precipitation should limit
highs but lows will be above normal.
12z models have trended towards strengthening the upper ridge over
the southeast states late in the week. The periphery of this ridge
pushes into the Ohio Valley while at the surface the boundary
appears to weaken and lift north. This will allow temperatures to
warm and generate moderate instability. So even weak forcing...which
cannot be resolved well that far out in time...could produce some
convection. Thus chance of showers and thunderstorms...albeit lower
than middle week...will persist through the weekend.
Aviation /08z Monday through Friday/...
low pressure in the upper atmosphere will move east and weaken
today...leaving surface high pressure centered to the east. Clouds
will show a decreasing trend...with scattered cirrus expected by
the end of the forecast. Some br may develop early this morning in
residual low level moisture and light winds. Otherwise...look for
VFR to persist through the period. Winds will become southwest
ahead of a cold front...while speeds remain under 10 knots.
Outlook...thunderstorms possible on Tuesday.