NWS Forecast Discussion
000
FXUS61 KCTP 261125
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
725 AM EDT Fri Apr 26 2024
.SYNOPSIS...
High pressure near Ottawa Canada will provide a relatively cool,
east to southeasterly flow of air today, but conditions will be
dry.
A warm front will drift northeast across the Commonwealth
Saturday but moisture associated with it will be limited and
showers occurring along and ahead of this boundary will be
relatively light.
Daytime high temperatures will jump by around 20 degrees on
Sunday with just a few, scattered showers or thunderstorms
across the northern Mountains of the state.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A very weak, surface trough extended from Southwestern PA into
the Central Mtns. This boundary will combine with limited low
level moisture being transported off the Western Atlantic to
bring some shallow morning stratus/stratocu clouds over the
Laurel Highlands and South Central Pennsylvania.
Vertical Mixing reaching up to 4-5 kft agl will greatly dissolve
this cloud layer leaving just scattered, cumulus pancakus for
the late morning and afternoon hours.
Low humidity once again today will create excellent vsby as
layer PWAT values are only around 0.3 of an inch.
Temps will be 3-6 deg warmer than Thursday. Look for high in
the upper 50s across the Northern and Western Mtns and low 60s
in the Central and Southern Valleys.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Showers along a warm front will spread into the Western
Alleghenies very late tonight or more likely early-mid morning
Saturday - based on the latest operational model/HREF
consensus.
PWATs will surge from west to east very late tonight and
Saturday, reaching 1-1.2 inches, along and in the wake of a warm
front. Late Saturday morning through mid afternoon Saturday
holds the greatest chance for showers. QPF will be quite light,
ranging from 1-2 tenths of an inch across the Western Mtns to
between 0.05 and 0.10 across the Central Mtns and just a few
hundredths of an inch expected across the Southeast.
Min temps tonight will be 6-12F milder than early this Friday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Lingering clouds with just some patchy drizzle and light fog are
possible later Sat night. Mins Sat night/Sunday morning will
climb by another 7-9 deg F compared to readings early Saturday.
Brightening skies and markedly warmer conditions appear likely
Sunday, as the warm front lifts north of the region. However,
ensemble plumes indicate scattered PM convection is possible,
especially over the N Mtns, where progged pwats are highest and
temps aloft coolest.
Fair and unseasonably warm weather is likely Monday, as
anomalous upper level ridge crests over the state. Mean 850mb
temps near 15C supports max temps in the low to mid 80s. All
medium range guidance points to a good chance of PM convection
Tuesday associated with the passage of a mid level shortwave.
Diverging model solutions and greater uncertainty then creep
into the forecast the second half of next week. Upper level
ridging and above average temperatures look very likely.
However, timing differences exist with regard to an upstream
trough and associated cold front late next week. Expect a
widespread round of convection to accompany the front either Thu
PM or Friday.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
A few patches of low clouds can be seen on satellite this
morning across southern portions of Central Pennsylvania. While
they are decreasing in coverage, there is a low probability
(around 20%) that they could lead to brief periods of MVFR
ceilings at JST for the next hour or two. However, confidence
in this occurring is too low to include it in the TAF. Once
these clouds dissipate, high pressure will allow for clear skies
through most of the day.
High clouds will begin to move in from the west ahead of an
approaching warm front and ceilings will begin to lower from
west to east after 00Z Saturday. Ceilings and visibilities will
begin to drop to IFR after 12Z on Saturday as rain showers
begin to move into the region.
Model soundings indicate the potential for a brief period of
LLWS at BFD and JST this late this evening as winds around 1500
feet increase to 35 to 40 knots.
Outlook...
Sat...Scattered shra. IFR cigs possible Central Mtns.
Sun...AM low cigs possible, mainly N Mtns. Isold PM tsra
possible.
Mon...No sig wx expected.
Tue...Sct PM tsra impacts possible.
&&
.FIRE WEATHER...
Fuel moisture may fall below 10% over the next two days.
Return flow around departing high pressure on Friday may
slightly increase the potential for spread on Friday afternoon,
mainly across the higher terrain to the NW of a KCBE to KAOO and
KUNV line where SE wind gusts into the mid and upper teens are
possible for about 3 hours this afternoon.
MinRH this afternoon (Fri) is forecast to be mainly between 30
and 35 percent, though the Laurel Highlands will only dip to
between 40 and 45 percent.
An approaching warm front will result in a cloudy and
relatively cool Saturday, with a chance of showers accompanying
the passage of a weakening, south to southwesterly low level
jet. Weak large scale forcing under an upper level ridge should
result in minimal rainfall. Most likely rainfall by Sat PM based
on ensemble plumes ranges from around 0.2 inches over the N
Mtns, to just a few hundreths over the southeast counties.
Increasing low level moisture/dewpoints along with some rain will
limit fire weather concerns this weekend.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 8 AM EDT this morning for PAZ004-005-010-
011-017-018.
Frost Advisory until 8 AM EDT this morning for PAZ019-024>028-
045-046-049>053-056-057-059-063-065-066.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Lambert/Dangelo
SHORT TERM...Lambert/DeVoir
LONG TERM...Fitzgerald/NPB
AVIATION...Bauco
FIRE WEATHER...Steinbugl
NWS CTP Office Area Forecast Discussion
