994
FXUS61 KCTP 292152
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
552 PM EDT Mon Apr 29 2024

.SYNOPSIS...
-Well above average temperatures will persist this week with
 highs in the 70s and 80s; near-record highs possible today.

-Cold fronts Tuesday and Friday-Saturday will be accompanied by
 up to a several hour period of showers and isolated
 thunderstorms. There is potential for brief heavy downpours
 with the storms.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
Near, or in some locations - (KAOO KBFD and KIPT) - record
warmth covered the region this afternoon with temps in the 80s
and moderately high sfc dewpoints in the mid to upper 50s.

Little mesoscale forcing and slight anticyclonic flow at low
levels with dry air and weak lapse rates or a nearly isothermal
layer occupying parts of the mid levels was negating any
significant vertical development of the expansive, high-based cu
field in the broad warm sector.

Weak, westerly 925-850 mb theta-E advection, combined with the
presence of an ill-defined lee trough and sfc quasi-stnry
boundary near the PA/NY border north of KIPT will bring a low
(20-30 probability) for a shower or low-topped TSRA into this
evening across our NE zones.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH TUESDAY NIGHT/...
Tonight will be similar to Sunday night with cu cloud bases
eroding/lifting by about 1000 ft and total sky cover from 2 or 3
layers adding up to SCT.

Temperatures will fall to near the dewpoint temperature (which
should stay steady or slowly drift up into the upper 50s to low
60s). Some increasing high clouds will begin streaming in
overnight ahead of an approaching cold front. A few high res
models try to develop a cluster of showers and maybe an embedded
storm moving NNE across the central mountains later this
evening, but dry conditions and the aforementioned stable mid
levels should prevail for most.

By Tuesday morning, low pressure from the Central Plains will
move northwest of the area, bringing a weak sfc cold front
across the area during the morning and early afternoon hours.
Showers are expected at the onset Tuesday morning across NW PA.
The surface low will transfer its energy to a developing coastal
low on Tuesday evening. This will help focus moisture
advection and elevated instability across eastern PA where a few
stronger showers and thunderstorms are possible. PWAT values of
1.25" are near the 99th percentile for this time of year and
will support torrential rainfall. With storm motions in a
northeasterly direction, some training is possible and could
lead to isolated flash flooding, which as prompted a Marginal
Risk of Excessive Rainfall from the Weather Prediction Center.
Recent dry conditions may mitigate any major concerns.

Showers will gradually weaken overnight Tuesday into Wednesday
morning, but a lingering stationary boundary will keep
cloudiness and unsettled weather around into the first part of
Wednesday. Another mild night is in store across the southeast
where clouds will stay put and temperatures remain in the low
60s. Some clearing appears possible in northwest PA and could
support lows touching the upper 40s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Showers become more scattered in nature Wednesday evening with
dry conditions expected by the overnight hours as an upper-
level ridge takes hold over the region.

Model solutions have started to latch onto a stronger upper-
level ridge solution, providing fair weather on Thursday and
into the first half Friday.

A low-pressure stationed over the Great Lakes will bring about
the next sfc cold front across central PA later on Friday and
throughout the day on Saturday. There is fairly good agreement
with deterministic model guidance in regards to precipitation
associated with the frontal passage, although timing remains the
biggest uncertainty at this time. The timing is likely to have
a big impact on observed temperatures on Saturday. In the warmer
scenario, a slower frontal passage would allow temperatures to
reach the mid to upper 70s areawide. A faster arrival of
precipitation and clouds could keep temperatures in the upper
50s to middle 60s. Have opted for a middle of the road scenario
at this point with highs in the 60s to low 70s.

After the frontal passage Saturday, the upper pattern trends
more zonal supporting seasonable temperatures with occasional
chances for rain for the first full week of May.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
High pressure ridge directly overhead will allow for VFR
conditions to continue across the area with scattered cumulus clouds
between 5000 and 8000 feet during the late afternoon/early
evening followed by some thin cirrus and patchy mid level alto
cu clouds later tonight.

Winds will generally average 6-8 KTS, though there could be
some gusts to 15 knots through dusk before becoming light and
variable.

An isolated shower or thunderstorm cannot be ruled out late this
afternoon/evening across the north where slightly cooler
temperatures aloft will coincide with the intersection of an
east/west stationary front and lee trough extending from North
of KIPT south through the Susquehanna Valley. Any impacts would
be brief and generally MVFR.

Upper level ridging begins to break down this evening and mid
level temps will cool slightly late tonight ahead of an
approaching cold front. A few stray showers moving NNE will be
possible after 03Z Tuesday. Some fog could develop once again
late tonight, though there is considerable disagreement in the
guidance regarding this. As of now it seems like BFD and IPT
would again be the most likely to see fog develop, but other
sites could see visibility restrictions as well.

Outlook...

Tue...Isold PM tsra impacts Eastern PA. Evening low cigs poss W
Mtns.

Wed...Early AM low cigs possible W Mtns.

Thu...No sig wx expected.

Fri...Evening showers/cig reductions possible.

&&

.CLIMATE...
Record high temperatures were set at the following locations
today (Monday):

SITE        2024 OBS     PRVS RECORD
Altoona          86F     83F (1956)
Bradford         82F     76F (1984)
Williamsport     89F     86F (1942/1974)


&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert/Banghoff
LONG TERM...Banghoff/Tyburski
AVIATION...Lambert
CLIMATE...Banghoff/Colbert