Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
913 PM EST Sat Nov 28 2015
areas of light rain will end from the north tonight and early
Sunday as a cold front sags through the upper Ohio region.
Near term /until 6 am Sunday morning/...
evening update...the changes made to the forecast were not
particularly large and generally centered around pulling
southward the back edge of probability of precipitation this evening around and north of
Pittsburgh and the I-70 corridor in Ohio. The regional radar
mosaic has revealed the back edge pulling eastward as the upper
jet streak right entrance region supporting ascent over the
majority of the region north of the surface front has been falling
apart and trucking eastward.
Additionally...dewpoints are falling toward 30f across the far
northern reaches of the area and even into the middle 20s just to the
north of Lake Erie. With cold advection and northerly flow
underway...this drier air will be making its way into at least the
northern fringes of the County Warning Area. With this in mind...low temperatures
were brought down a few degrees across the north...while farther
south...drizzle/light rain and low clouds will keep a floor under
Short term /6 am Sunday morning through Tuesday/...
residual rain over southern zones is prognosticated to be shunted further
southward on Sunday as cool high pressure builds. The dry reprieve
looks to be brief though as digging low pressure over the Central
Plains is expected to push warmth and moisture through its eastern
flank and back over the region on Monday. Probability of precipitation were increased
from south to north through the day...with likely probs continuing
through Tuesday as that low develops toward the Great Lakes and
sends an occluding/cold front across the upper Ohio.
Short term precipitation probs...and variable temperatures were forecast using
the guidance blend.
Long term /Tuesday night through Saturday/...
the aforementioned front is currently timed for a Tuesday night
passage. The forecast thus features diminished probability of precipitation...although
chance numbers were maintained under The Crossing upper low. Dry
weather is expected for the close of the with high pressure
projected to rebuild.
The fading probability of precipitation and near-average temperature forecast were constructed
using the guidance blend.
Aviation /02z Sunday through Thursday/...
as the cold front continues to sag south of the cwa, the rain will
gradually sag south and through the southern part of the
region. IFR ceilings will persist overnight with low level moisture
below a temperature inversion. Most visibilities should be in the
3-5 mile range. A gradual improvement to MVFR and eventual VFR is
expected for ports from pit north sun with dry advection.
Outlook...Sunday night through Thursday/...
low ceilings should persist through sun evening S of pit. Low pressure will
return restriction chances late Monday through Wednesday.