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000
FXUS61 KPBZ 180915
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
515 AM EDT Thu Apr 18 2019

.SYNOPSIS...
Conditions will remain mostly dry until a low pressure system
impacts the region early Friday morning and into the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Spotty showers have shifted east of the area with the supporting
shortwave. Strong warm advection aloft is expected to increase
stability today so convection chances remain low. Improved mixing
with the rising sun is expected to support highs 15 to 20 degrees
above the averages as well as gusty wind near 25 kt.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A few isolated rain showers may develop in advance of the approaching
cold front during the late evening hours. The majority of
precipitation is expected to come into our region by late Friday
morning/early afternoon as the upper level trough, aligned with a sfc
low, stalls over the Appalachian Mountains.

Sounding analysis shows that while wind shear will be respectable
high, close to 30kts at the low levels, instability will be hard to
come by due strong warm advection aloft--CAPE values go no higher
than 300 J/kg. If clouds break and temperatures have a chance to
advance higher than expected, a few strong thunderstorms MAY form.
The most likely region for these storms to develop will be southeast
of Pittsburgh and the main threat would be wind damage.

Due to the absence of a strong upper level jet downstream of this
upper level low, it will take its time for this system to move out
our region. It will continue to linger near West Virginia by
Saturday evening. However, dry air moving through the mid-levels will
help diminish widespread precipitation chances.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The upper trough will finally shift east Saturday night, allowing
showers to become more scattered. Multiple shortwaves embedded in a
broad upper level ridge Monday through Wednesday may allow isolated
rain showers to develop.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
VFR conditions are expected to be marred today only by sfc gusts of
20 to 25kt as pres gradient and mixing in the incrsg warmth on sly
flow improve.

Expect llvl wind shear development tonight with llvl jet through the
ern flank of TN Valley, to Mid OH Valley low pres. Overall condition
deterioration with eventual restrictions and rain should be expected
for Friday as that system encroaches on the Upr OH Region.

.Outlook...
Restrictions and showers are likely through the weekend as strong
low pres traverses the region.

&&

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

&&

$$