Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
618 am EDT Monday Sep 1 2014
isolated to scattered showers and storms are possible again today.
A cold front will bring more widespread showers and storms
Near term /until 6 PM this evening/...
no changes were needed for the pre dawn update.
not much to target on today as far as convection is concerned.
Atmosphere will remain unstable as we are stuck under an air-mass
with surface dewpoints near 70 degrees. Forecast soundings are
holding on to a saturated layer for most of the morning hours.
Layer somewhat mixes out in the afternoon...which should allow for
some sunshine. A weak upper level disturbance will swing through
in the afternoon which could provide enough ascent in this
unstable regime to fire convection. In accordance with this...
have slight chance/low chance probability of precipitation in the afternoon.
Temperatures will be above normal and humidity levels high.
Short term /6 PM this evening through Wednesday/...
the next shortwave trough will move through Tuesday with a weak
frontal boundary. Models continue to show an unstable atmosphere
as the high surface dewpoints remain entrenched. Timing on the
boundary appears to be in the afternoon viewable with a line of
low level forcing. Tuesday looks like a good bet to see widespread
showers with the risk for storms. Should be plenty of cloud cover
Tuesday which will limit the strength of convection. Would think
the greater threat would be heavy downpours as precipitable waters will rise to
near 2 inches right ahead of The Crossing boundary. Upper level
support will quickly move to the east in the evening...carrying
the boundary with it. This will bring an end to the threat for
Drier air will eventually settle in over the region on Wednesday.
Temperatures will still be warm but conditions will be noticeably more
Long term /Wednesday night through Sunday/...
high pressure will remain along the East Coast through Friday...
allowing conditions to remain dry. Cold front will bring showers
and storms for the beginning of the weekend...with cooler drier
air for the end of the long term.
Aviation /10z Monday through Friday/...
expect a gradual rtn to VFR by this afternoon as warmth and southerly flow mix out
the St blanketed over the region. More restrictions are anticipated
early on Tuesday with prefrontal convection.
Outlook.../tonight through Friday/...
shower/thunderstorm rstrns are likely with a Tuesday cold front.