Area Forecast Discussion
Issued by NWS State College, PA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCTP 230546
Area Forecast Discussion
National Weather Service State College PA
146 AM EDT MON MAY 23 2016
The seasonably cool and wet weather pattern will continue tonight
with improving conditions expected Monday into Tuesday. A noticeably
warmer and more summer-like pattern is forecast from mid week into
the holiday weekend.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
20z water vapor loop shows upper low ovr northern virginia. On
radar, light stratiform rain continues to fall across most of
central and southern Pa within region of lg scale forcing north of
upper low. On the nw periphery of upper low, there has been enough
diurnal heating/destabilization to support sct tsra ovr parts of
Warren/Mckean counties. Even some pea sized hail reported arnd 3pm
The HIRES deterministic and ensemble blend, which has performed
quite well in simulating the pcpn pattern over the past 24 hours,
supports max POPs early tonight over the southwest and south
central zones before a gradual north to south drying trend
overnight, as upper low sinks south.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
Model agreement is good with respect to additional shortwave
energy being absorbed into upper level trough crossing the Mid
Atlantic piedmont tonight and eventually closing off as it starts
to move northeastward along/off the coast on Monday. Expect an
axis of scattered showers with a few embedded tstms to develop
within a low level convergence axis on the backside of the closed
low...with the greatest coverage during the afternoon hours when
daytime heating combined with cool temps aloft/steep mid level
lapse rates will result in marginal instability. HIRES
deterministic and ensemble blend favors the southeast 1/2 of the
area with the highest pcpn probs through 24/00z followed by a
decreasing/drying trend into Monday night and Tuesday morning.
Maximum temperatures will rebound into the upper 60s and low 70s
which is near to slightly below normal with the largest departures
on the order of about 5 degrees across southern PA.
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Extended guidance is trending close to recent solutions..with
the much heralded advertisement of eastern ridge/western trough
holding sway and bringing the arrival of summer like
temperatures and humidity.
Slowly filling and lifting out upper low will be the focus early
in the period and will still keep the mention of a shower
possible overmainly eastern areas into Tuesday. By Wednesday...
central PA will bein favorable position for drying and arrival of
risingheights...delivering quite warm conditions as subtropical
ridgestarts to influence our weather. The area remains susceptible
tomainly afternoon isolated convection on Thu-Fri as zonal WSW
flow in ring of fire regime could focus some activity. However...
strong amplification of the upper ridge into central and eastern
PA Sat and Sun should put a cap on convective chances for a time.
The picture becomes muddled by late Sunday and Monday as
rex blocking along the eastern seaboard may deliver a rich fetch
of tropical moisture towards the mid atlantic and points northward
by that time...at least introducing a better chance of scattered
showers and thunderstorms at that time (Mon-Tue). Northern
stream energy sliding across the eastern GLAKS could combine with
this moisture flow Mon night and Tuesday for more focused activity.
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --For the 23/06z TAFs through 24/06z | Issued 145 am EDT 5/23/16
Mid level clouds over south central PA at 130 am. Band of showers
over central NY moving sw.
Main issue overnight is where there is some clearing...there is
fog and ground fog. Expect a wide range of conditions overnight.
06Z TAFS sent.
Earlier discussion below.
Showers continue to rotate from east to west across the region as
an upper level low pressure moves slowly to the southeast to the
mid Atlantic states. Areas of fog and drizzle will drop any site
to MVFR or briefly IFR overnight with light winds.
As the upper low moves along the eastern seaboard Monday, enough
instability remains for an afternoon shower or thunderstorm. Did
not try to paint any specific location but rather a general chance
of thunder /VCTS/.
Tue-Wed...VFR/No sig wx expected.
Thu-Fri...Chance of mainly P.M. showers/tstms.
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LONG TERM...DeVoir/La Corte