Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KPBZ 202303
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
603 PM EST Mon Nov 20 2017

.SYNOPSIS...
A cold front will bring the next chance for precipitation on
Tuesday night. Dry weather and below average temperatures can
then are expected for the remainder of the week.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Retreating high pressure will ensure another dry night, marred
only by encroaching cirrus with a weak shortwave. Warm advection
on the van of the next shortwave trough is forecast to further inhibit
a radiational temperature drop. Nevertheless, areas which received
accumulating snow yesterday may still see readings a couple degrees
below guidance given the initially colder start. Changes for the
early eve update were thus minor and confined mainly to hourly
trends.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
Warm advection on southerly flow and limited insolation are
progged to drive Tuesday high temperature a few degrees above
the seasonal averages as the aforementioned trough advances.

That cold frontal system is timed plough over the Upper Ohio on
Tuesday night. Model indications of strong differential PVA and
frontogenetical forcing seems sufficient to forecast likely to
categorical POPs with the frontal passage; however, the cold
airmass in the wake of that front is not expected to be deep
enough to sustain low level convection/i.e. snow showers for
long. Any post frontal snow accumulation should be thus be limited
to the I 80 corridor and ridges. Less than an inch is
anticipated even in those areas.

High pressure will then ensure a dry midweek and Thanksgiving
holiday, but sub average temperatures are progged to be
maintained under broad Eastern CONUS troughing.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
More active conditions look to return into the extended as a
longwave trough starts to become established over the eastern
CONUS. Successive clipper-like systems look to drop into the
area starting Friday night. Initial warm advection will mean all
precipitation will likely start as rain, but as a couple of
systems pass and cold advection becomes a bit more efficient,
most areas should gradually change toward better chances of snow
by Sunday.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Eroding high pressure will maintain VFR through Tuesday although
an increasing pressure gradient in advance of the next trough
digging across the Great Lakes will support low level wind shear
tonight, and wind gusts around 20 kts on Tuesday.

Restrictions are then likely with a Tuesday night cold front.

.Outlook...
Subsequent cold avection is expected to maintain MVFR cigs into
Wednesday, but improvement can be expected as the day progresses.
The next chance for restrictions is forecast with an early Saturday
cold front.

&&

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

&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.