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FXUS61 KCTP 191752
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
152 PM EDT Fri Jul 19 2024

.SYNOPSIS...
* High pressure and northwest winds will bring ample sunshine
  and lower humidity today with seasonable temperatures.
* Southerly winds usher in an uptick in humidity on Saturday
  with scattered afternoon showers and thunderstorms.
* Dry conditions on Sunday into Monday precede a more unsettled
  pattern next week with seasonable temperatures.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure centered over northern Indiana late this morning
had a ridge extended east into PA. This weather feature will
supply us with abundant sunshine and just a scattering of fair
weather cu based between 3500-4500 FT AGL across mainly the
northern half of PA

Near normal temperatures and comfortable humidity levels will
continue today. Highs this afternoon will vary from the upper
70s over the highest elevations of the north and west to the
upper 80s in the Southeast Metro Areas.

Diurnal ranges of 20 to 30F are pretty typical for a relatively
dry summertime airmass. Dewpoints will remain in the 50s for
most today and could even mix out into the upper 40s in a few
spots, which will fell fantastic relative to the recent
prolonged stretch of hot and humid weather.

An approaching warm front is likely to spread increasing
clouds/humidity into the region Friday night, but the odds of
any rain look slim. High clouds will overspread most of the
forecast area by daybreak Saturday with lower clouds more
scattered in nature and focused across the spine of the
Appalachians. Patchy fog could again develop again tonight into
Saturday morning across the NW mtns given the increasing
moisture and scattered cloud cover expected, though coverage is
not expected to be as extensive as this morning. Morning lows on
Saturday will trend a few degrees warmer than this morning -
from the middle 50s in the northwest to upper 60s southeast.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
A short wave disturbance will bring increased rain chances for
the afternoon on Saturday when isolated to scattered coverage of
showers and storms develops over parts of the Laurels, SC
Mountains and Central Mountains. Best chance for rain appears to
be along the spine of the Appalachians with current rainfall
amounts generally less than a tenth of an inch, with isolated
pockets exceeding 0.5 inches possible. Generally weak forcing
and shear should preclude any severe or flooding potential. In
fact, with expanding drought conditions across the region,
rainfall will be beneficial for all recipients.

There will be a noticeable uptick in humidity on Saturday for
everywhere except the northwest mountains with temperatures
staying pretty steady relative to Friday. High pressure will
retake control of our weather Saturday night with clearing skies
expected and patchy fog in locations that received rain earlier
in the day. Dry conditions prevail on Sunday with increasing
clouds but still partly cloudy skies. Temperatures will trend a
few degrees above normal Sunday afternoon as high temps across
the south approach 90 once again. Dry weather continues Sunday
night as clouds continue to stream in and humidity increases.
The uptick and clouds and humidity will help overnight lows
continue to moderate each day into next week.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Near to below normal pwats beneath a weak area of high pressure
will provide a rain-free and less humid end to second-to-last
weekend of July. There should also be good viewing at night for
the full Thunder or Buck moon with patchy fog developing in the
northern river/stream valleys into early Monday morning.

Latest model and ensemble guidance shows an amplified pattern
that will be fairly slow to evolve next week. The key synoptic
features will be a wavy front on the leading edge of a Great
Lakes to southern Plains mean trough that will promote multiple
days of diurnally enhanced thunderstorms and potential heavy
rainfall across the region. The southern tier of central PA
could really use some rain to lessen the impacts of moderate to
severe drought conditions (D1-D2 drought monitor).

Max/min temperatures (80-90/60-70F) will remain above the
historical average with for late July with humidity/dewpoints
returning to elevated levels; however the heat and humidity
combination is not expected to be excessive.

WPC introduced a marginal risk ERO for day 5/Tuesday with
guidance ramping pwats to 1.5-2.0 inches or +1-2SD. The Tuesday
into Wednesday timeframe appears to have the best odds for
heavy rainfall (max POPs) before pwats trend lower from NW to
SE as the frontal zone slowly presses to the southeast with
time by late week.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
There remains high (> 95%) confidence in VFR conditions through
at least 06Z Saturday. SCT-possibly BKN cloud bases over the
ridges near the PA/NY border will be near 3000 FT AGL until 17Z
before lifting to 3500-4000 ft AGL.

Patchy fog is expected to be slightly more widespread than last
night with slightly higher confidence in fuel-alternate
restrictions at BFD after 08Z Saturday. LAMP guidance outlines
some potential for IFR conds as early as 06Z; however, have
hedged closer to persistence for this forecast cycle. There is a
bit of uncertainty on how far south fog mentions will be needed
with lower potential and confidence (20%) of restrictions at
UNV/IPT so have opted to show some gradual lowering of cigs/vsby
in the 12Z TAF cycle.

Outlook...

Sat-Mon...Primarily VFR/unrestricted conditions. Patchy late
night/early morning fog and low ceilings are possible.

Tue...More widespread PM showers and thunderstorms could lead
to at least brief restrictions.

&&

.CLIMATE...
The average temperature from July 1 to July 18 at Harrisburg is
81.6F which is the warmest July month-to-date.

&&

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

&&

$$

SYNOPSIS...Lambert/Banghoff
NEAR TERM...Lambert/Banghoff
SHORT TERM...Banghoff
LONG TERM...Steinbugl
AVIATION...Lambert/NPB
CLIMATE...Steinbugl