Area Forecast Discussion
Issued by NWS -- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KPBZ 232145
Area Forecast Discussion
National Weather Service Pittsburgh PA
545 PM EDT Sun Apr 23 2017
High pressure should maintain dry weather today. Low pressure
is expected to track along the East Coast, resulting in
periodic rain chances mainly east of I 79 for the start of the
new work week.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --A weakening upper jet streak is currently transitioning through
and eventually northeast of the area. With weak layer RH values
below its right entrance region, the net effect of this is just
dynamically allowing for the cirrus shield to expand
northeastward across the area this evening, while deep moisture
remains well to the south.
As we approach the overnight hours, southerly flow in the mid-
levels will likely start to become better established. This will
work to increase mid-level moisture toward the southeastern
portions of the forecast area as well as the ridges. With the
increase in mid-level moisture as well as the northward
migration of another jet streak right entrance region, rain
chances will increase overnight in the southeastern zones.
The addition of clouds to the area will likely keep a bit more
of a lid on temperature falls tonight relative to last night.
Even still, largely normal overnight temperatures look to be in
-- End Changed Discussion --
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
The cut-off upper-level low will dig further into the
southeastern U.S. Monday. As this occurs, very little northwest
progression of rain chances will be achieved. Models hinting at
weak ascent streaming northward in the form of a deformation
band, but activity along this will largely be negated by the
presence of low-level dry air re-enforced by downsloping flow.
As a result, will keep a tight gradient of PoPs along the
Ridges, with only slight chance west.
The best chances of rain outside of the higher elevations should
come Tuesday as the low turns the corner and begins to fill over the
Mid-Atlantic. Strong easterly flow will continue to advect moisture
into the eastern facing upslopes, and some rain may be able to creep
east to west over the higher elevations. The weakening low will then
be pushed away by a building ridge through the upper Ohio Valley
late Tuesday, establishing areawide dry conditions by Wednesday
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Ridging and rising heights in response to an approaching
Midwestern trough should result in dry and warm weather for mid
week. The flow is progged to amplify by late week as broad low
pressure develops over the western CONUS. One cold front will
stream through Thursday with showers and thunderstorms likely.
This system will then open the door to more disturbances keeping
the forecast wet through the weekend. Temperatures will be above
average through the extended.
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
High pressure will maintain VFR and light northeast to east sfc
wind into Monday.
The next chance for general restrictions is expected with mid
week low pressure.