pa discuss
Office: CTP
FXUS61 KCTP 260551
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
151 AM EDT Fri Apr 26 2024
.SYNOPSIS...
High pressure will provide dry cool and dry conditions with
widespread frost and freeze conditions expected Friday morning.
Clouds will increase late Friday leading to a chance of showers
Friday night and into the weekend before it turns much warmer
for Sunday and even warmer still for most of next week.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
The thicker of the high clouds are slipping to the SE and
revealing only a small patch of lower clouds in
Somerset/Bedford. However, lots of guidance expands this patch
of clouds through the night with help from the gently upsloping
SSE flow. Overall, the current forecast covers this. Now, the
temps are trailing the forecast dip by a few degs. The
dewpoints are still very low across the nrn half of the CWA.
That should allow them to catch up. The main trouble with temps
right now is the SE where temps are the clouds have just
dissipated/left and there was recently a 20KT gust at LNS.
Dewpoints there are still in the u30s. But, we expect the temps
in the SE to get back on track shortly as the pressure gradient
relaxes. Will continue to hold all the frost/freeze flags as is.
There is the potential for some AM fog in the SE, too, with
those higher dewpoints. Lack of recent rainfall is a negative
for fog, though.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM SATURDAY/...
Friday will be another fair day under the influence of
retreating high pressure, with return flow freshening over
western areas, and especially the Laurel Highlands. Rain free
wx conditions will continue with morning sun mixing with high
clouds throughout the day and max temps trending warmer into
the upper 50s to lower 60s. Showers along a warm front are
likely to move into the western Alleghenies very late Fri night
or early Saturday morning based on the latest operational
model/ens consensus.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
An approaching warm front will result in a cloudy and relatively
cool Saturday, with a chance of showers accompanying the passage
of a weakening 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. 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 /06Z FRIDAY THROUGH TUESDAY/...
VFR conditions are expected to continue across most of the area
tonight under high pressure. The exception will be across
southern portions of Central PA where lingering low level
moisture could lead to some low cloud or fog formation. An area
of low clouds currently to the south of the area are beginning
to expand northward and will likely approach JST and AOO by 08Z.
Most guidance suggests that those airfields will remain VFR
through the night, but the HREF/SREF show a 20-40% chance of
MVFR or potentially IFR ceilings developing at JST into the
morning. Confidence in this outcome occurring is low, though.
Any clouds and fog that form overnight will gradually decrease
in coverage in the morning, though clouds could stick around
slightly longer across the Laurel Highlands with light upslope
flow. Otherwise, mainly clear skies are expected area-wide. An
approaching warm front will lead to an increase in high clouds
after 00Z Friday.
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. With
light winds today, the risk of fire spread remains very low.
However, return flow around departing high pressure on Friday
may increase the potential for spread on Friday afternoon.
MinRH this afternoon (Thu) is forecast to drop to 15-25% over
the northern half of the area with potential downside to 10%.
MinRH over the southern tier districts along the MD line is
forecast between 30-40%. The wind will <10 mph from the
north/northeast.
MinRH is forecast to recover a bit Friday afternoon bottoming in
the 25-40% range. However, the wind will increase from the south
southeast with gusts to 20 mph at times over the higher terrain
along the southern Allegheny Plateau.
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...DeVoir
NEAR TERM...DeVoir/Dangelo
SHORT TERM...DeVoir
LONG TERM...Fitzgerald/NPB
AVIATION...Bauco
FIRE WEATHER...Steinbugl
Office: PHI
FXUS61 KPHI 260655
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
255 AM EDT Fri Apr 26 2024
.SYNOPSIS...
High pressure moves offshore today. A warm front attached to
low pressure over the Great Lakes moves by Saturday. Highs
pressure returns for Sunday and into next week. Another low and
front arrives for Tuesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
High pressure is centered over northern New England and
southern Quebec early this morning, with a light pressure
gradient over our region. Dew points dropped notably yesterday,
so with dry air, light winds and clear skies, it looks as though
radiational cooling should be excellent through dawn. Will watch
obs closely to see if freeze/frost headlines need to be
cancelled anywhere, but doesn't currently look like we'll need
headline expansion anywhere given temps are running near to
slightly above expectations.
Otherwise, looks like a dry and mostly sunny day as the high
very slowly drifts eastward through the day. The sun should
allow rapid warming but the light southeasterly to easterly
flow on the south side of the high will limit the climb in temps
especially close to the ocean. Overall expect highs in the 60s
inland to 50s near the coast.
Tonight should stay mostly clear, but the easterly flow likely
moistens up the low levels just enough that, when combined with
some approaching high clouds ahead of a warm front and the
warmer start plus warm advection aloft, should limit the drop.
Might need some frost headlines but think another widespread
freeze is off the table... possibly for the rest of the season?
We'll see, but either way, milder than tonight. Lows mostly 30s
to low 40s.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A transition to early summer readings Saturday and Sunday. An
upper ridge will build across the area thru the period and as
this happens, low pressure moves by to the north, bringing a
warm front thru on Saturday. There will be plenty of clouds
along the frontal boundary, increasing through the day and into
the overnight period. The high elevations of the Poconos and NW
New Jersey could see an isolated light shower during the day,
but the best chance for showers (20-30%) will be along the I-78
corridor and points north.
Mild and dry weather will be around for Sunday. Following the
warm front, a deep southerly flow will arrive over the area, so
increasing warmth and humidity is expected. Highs Sunday will be
in the upper 70s/low 80s in most spots, but cooler near the
shore and up across the Poconos. A mild night expected as well
with lows only reaching the mid 50s to around 60.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Very warm temperatures for late spring will remain in place as
the upper ridge starts out across the eastern US to start off
the work week. High temperatures will likely be the warmest thus
far this season with much of the region reaching the low to mid
80s! Gradually, this ridge weakens and allows more scattered
shortwave energy to arrive across the area. For Tuesday and into
Wednesday, a cold front will approach the area and then wash
out as it moves through. Some scattered showers and
thunderstorms will certainly be possible, mainly Tuesday
afternoon and Tuesday night, but overall probabilities remain
around the 25-45% range.
Another system will approach the region Thursday, though there
remains quite a bit of model spread in timing and evolution.
Sticking close to our consensus blend, leaving a 20-30% chance
for showers.
Temperatures remain above average in the mid 70s to low 80s
through Thursday.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...
Through today...VFR. East to southeast winds increasing to near
5-10 kts. High confidence.
Tonight...VFR. East to southeast winds dropping to 5 kts or
less. High confidence.
Outlook...
Saturday through Monday...VFR prevail. A few moments of sub-VFR
conditions possible Saturday night as a warm front pushes
through with scattered showers. Otherwise, a dry forecast.
Tuesday...VFR to start with sub-VFR conditions potentially
arriving in the afternoon and evening with the arrival of a weak cold
front.
&&
.MARINE...
Seas are diminishing and should be in the 2-4 foot range through
tonight with an east to southeast wind around 10 kts with gusts
up to 15 kts. Fair weather.
Outlook...
Saturday through Tuesday... Winds and seas will remain below
SCA criteria through the period. Fair weather expected.
&&
.FIRE WEATHER...
RH values will be in the 25-30% range today. However, with
winds so low, around 10 MPH or less, the threat for the rapid
spread of wildfire remains low. The morning shift will take
another look and coordinate with partners to see if any
statements are needed.
&&
.CLIMATE...
A few records could be approached early this morning.
ABE/Allentown 30 in 2001/1967/1934
ACY/Atlantic City Airport 28 in 1967
55N/Atlantic City Marina 34 in 1883
GED/Georgetown 30 in 1964
MPO/Mount Pocono 18 in 1919
PHL/Philadelphia 35 in 1967/1919
RDG/Reading 27 in 1972
TTN/Trenton 33 in 1919
ILG/Wilmington 32 in 1919
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Frost Advisory until 9 AM EDT this morning for PAZ070-071.
Freeze Warning until 9 AM EDT this morning for PAZ060>062-
101>106.
NJ...Frost Advisory until 9 AM EDT this morning for NJZ014-023.
Freeze Warning until 9 AM EDT this morning for NJZ001-007>010-
012-013-015>022-027.
DE...Frost Advisory until 9 AM EDT this morning for DEZ001>003.
MD...Frost Advisory until 9 AM EDT this morning for MDZ012-015-019-
020.
MARINE...None.
&&
$$
SYNOPSIS...OHara/RCM
NEAR TERM...RCM
SHORT TERM...MJL/OHara
LONG TERM...MJL/OHara
AVIATION...MJL/RCM
MARINE...MJL/RCM
FIRE WEATHER...
CLIMATE...
Office: PBZ
FXUS61 KPBZ 260801
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
401 AM EDT Fri Apr 26 2024
.SYNOPSIS...
Dry and warmer today. The risk for showers returns late tonight
and Saturday. Big warmup expected Sunday and Monday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:
- Dry and warmer today
------------------------------------------------------------------
Upper level height rises today as an amplified ridge axis moves
across the Upper Midwest. Surface high pressure will drift
across the New England States this morning. Low-level flow on
the backside the high may push some moisture back over the
region this morning. Seeing some differences in the possible
cloud cover from this moisture. The NBM keeps the highest
probabilities of total cloud cover bottled up on the eastern
side of the ridges, showing around 10% prob for >50% cloud cover
west of the ridges. HREF is more bullish with cloud cover
particularly later this morning and into the afternoon.
Indicating around 60% prob of >50% cloud cover. Will lean toward
the NBM solution as it did a good job with yesterday's
persistent cloud cover.
Increased warm air advection will nudge highs back above normal
today.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
KEY MESSAGES:
- Showers late tonight and Saturday with a warm front
- Warmer Sunday with an isolated shower/storm possible in the
afternoon
----------------------------------------------------------------
Upper level ridge axis will slowly move through Ohio tonight and
then across the rest of the forecast area on Saturday. A surface
warm front will trail just behind the axis and push northward
through the region late tonight and Saturday morning. Showers
will accompany the passing boundary. Rainfall looks to be light
with NBM probs of >0.1 inches around 30 to 40% tonight and 20 to
30% Saturday morning. The highest probs are generally over the
I-80 corridor through the period. Showers should end late
Saturday morning or early afternoon as the front will move well
north of the region. Thunderstorm chances appear minimal as
forecast soundings show little to no instability and a strong
low level inversion. Warm air advection is anticipated behind
the boundary, so temperatures will continue to moderate on
Saturday. A limiting factor for highs on Saturday will be cloud
cover behind the front associated with a shortwave trough that
will push the morning ridge east of the area.
Strong height rises return Saturday night and an impressive
ridge will take hold over the region on Sunday. A weak shortwave
will try and sneak over top of the ridge bringing a small
increase in shower/storm chances Sunday afternoon. The area with
the highest probs for measurable precipitation will be north of
Pittsburgh where 30 to 40% probs for >0.01 inches rest. With
such a strong ridge, and forecast soundings showing a cap, it
should be difficult for much activity to develop.
Warm air advection will continue on Sunday and temperatures will
rise into the 80s across much of the district.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
KEY MESSAGES:
- Warm with minimal chances of afternoon thunderstorms Monday.
- More widespread showers and possible thunderstorms with a
Tuesday cold front.
-------------------------------------------------------------------
Model ensembles continue to indicate a strong ridge Monday.
The ridge axis is expected to shift slowly eastward later
in the day, with slightly better chances for afternoon showers
and thunderstorms as a shortwave trough, and associated surface
cold front, begin to approach from the Midwest.
Temperatures mainly in the 80-85 degree range (outside of the
higher terrain) are expected Monday.
Showers are likely, along with a few thunderstorms, on Tuesday
as the trough and cold front cross the region. The precipitation
should end Tuesday night as the front exits.
By Wednesday, one thing is more certain; the ridge amplitude
will decrease. Clustered variability of the 500mb pattern sits
anywhere between a weak 500mb trough to a weak 500mb ridge. This
ridge breakdown may lean towards more unsettled weather.
Late next week, a central CONUS ridge may develop (shown in 3
out of 4 clusters). Should it develop, it is favored to move
east (as shown in 2 out of 3 clusters) and allow warmer-than-
normal temperatures to continue through next weekend. Some
alternate scenarios include 1) the ridge not developing,
whereby temperature would remain closer to normal in zonal flow
and 2) the ridge develops but does not move east and enforces
eastern troughing, which would keep temperatures below normal.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR is expected through this evening as the center of surface
high pressure moves east of the region. CU rule and model
soundings indicate scattered diurnal CU developing after
sunrise, as convective temperatures are reached. These should
dissipate by evening, though mid level cloud cigs will be
increasing ahead of an approaching warm front. A few showers
are expected toward the end of the 30 hr TAF period at PIT,
though VFR should continue.
Wind will veer overnight from N to ESE by morning. Speeds will
increase after sunrise, with some downsloping gusts around 20kt
at LBE and DUJ.
.Outlook...
Showers and restrictions are likely on Saturday with the
passage of the warm front. The highest SREF probabilities of
persistent MVFR are currently north of PIT. VFR is then expected
Saturday night through Monday as a ridge builds across the
region, though an isolated afternoon thunderstorm is possible
Sunday mainly north of PIT.
More widespread restrictions in showers and thunderstorms are
expected with a Tuesday cold front.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Frost Advisory until 9 AM EDT this morning for PAZ007-013-014-
020-022-077-078.
Freeze Warning until 9 AM EDT this morning for PAZ008-009-015-
016.
OH...Frost Advisory until 9 AM EDT this morning for OHZ039>041-
048>050-057>059-068-069.
WV...Frost Advisory until 9 AM EDT this morning for WVZ001.
&&
$$
SYNOPSIS...22
NEAR TERM...22
SHORT TERM...22
LONG TERM...22/Milcarek
AVIATION...WM
