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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 151247
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
747 AM EST Sat Dec 15 2018

.SYNOPSIS...
Rain expected through the weekend with the approach and passage
of low pressure. Snow chances return Monday and Tuesday with
cold flow off the Lake Region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Made some minor changes to the forecast, mostly sharpening the
northern PoP gradient for the next few hours based on radar/hi-
res model trends.  Forecast generally remains on track.

Previous discussion...

Rain will continue today as an area of deep low pressure tracks
northeast over the Ohio river valley. Rates have been relatively
low at 0.10 an hour or less...but expect a slight uptick in
intensity this afternoon and evening with increased upper level
support.  Since the rainfall will persist over an extended
period of time, flooding hazards are not likely. A few isolated
creeks may rise into action stage. WPC and OHRFC data was
primarily used for QPF amounts.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
By this evening the upper level low is expected to be
positioned over central Tennessee. Rain will continue to
progress, but rainfall rates will decrease overnight as the
system continues to transition ENE.


By Sunday night our region will be on the backside of the upper
level low and northwest flow will dominate; colder air will
gradually make its way into our region...with portions of our
northern counties and areas in higher elevations expected to
experience a light wintry mix late Sunday/early Monday morning.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Strong northwest flow should maintain snow shower chances in
the regions that usually benefit from lake enhancement. Dry
weather is still expected through mid week under a building
ridge ahead of a Western CONUS trough. Rain chances return later
on Thursday as an upper level trough advances across the Great
Lakes.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
Areas of MVFR/local IFR in rain are expected through the TAF
period as low pressure advances across the TN and OH Valley
regions. In between waves of rain, occasional improvement to VFR
cigs is expected.

Outlook...
Widespread restrictions with periodic rain are expected to persist
through Sunday with the crossing low. Restrictions are possible
Monday with a crossing upper trough.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

$$