Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
210 am EDT Monday Jul 28 2014
a broad area of low pressure will keep rain chances in today with
a drying trend through midweek. Below average temperatures will be
felt through the end of the week.
Near term /through today/...
as the surface low moves east of the area this morning...so do the
thunderstorms that cleared the area by about 05z. The current
water vapor loop shows the dry conveyor belt pushing in across our
south working towards a temporary drying trend...and even breaking
up the clouds across the region. However...another vorticity lobe on
the backside of the low is swinging through Lake Erie currently.
Already seeing additional showers and thunderstorms generating off
of residual outflow boundaries making their way on shore near
kcle. Have this wave timed to reach our northwestern periphery by about
09z with shower chances increasing southwestward once again
through mid-morning. While we will see spatial coverage of the
shower activity increase spreading south through the County Warning Area today...strength
will remain limited as instability wanes. Expecting gusty winds as
the low level pressure gradient remains tight and cold air advects
in behind the low. Near term models are a little more aggressive
with the erosion of the low level moisture this evening and thus have sped
up the drying trend tonight.
Short term /tonight through Wednesday/...
moisture will continue to wrap around the exiting trough on
Monday...keeping in the risk for showers. Atmosphere is not
showing a great deal of instability Monday and with lots of cloud
cover...storm threat should be greatly reduced.
Showers will end Monday night...and much cooler air will dive
southward over the upper Ohio Valley.
Tuesday should see an increase in sunshine...but with below normal
Long term /Wednesday night through Sunday/...
high pressure under upper level trough will provide a cool and
comfortable midweek. Another weak cold front may bring showers
Thursday. High pressure will return Friday. Warmer air and the
risk for showers for the beginning of the weekend.
Aviation /06z Monday through Friday/...
with the main surface low pushing east of the area...drier air is moving
in aloft with cloud cover at varying stages. Middle and high clouds
are continuing to break up and low level stratus is beginning to develop.
Expecting stratus and visible restrictions to spread throughout...but
timing will be difficult pinpoint. Shower chances will also
increase through the day as the middle-level cold air will give rise
to showers with isolated thunder chances. The cold air advection
and proximity to the surface low will combine for gusty northwest
winds today. Drier conditions with clouds breaking up tonight.
Outlook.../Monday through Thursday/...
no significant restrictions are expected through Thursday.