pa discuss
Office: CTP
FXUS61 KCTP 171835
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
235 PM EDT Wed Jul 17 2024
.SYNOPSIS...
- A cold front will push through the state through tonight
accompanied by another round of strong to severe thunderstorms
that will be focused across Central and Eastern Pennsylvania.
- High pressure will build in from the Great Lakes on Thursday
and bring mainly fair weather with seasonable temperatures
through the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Surface cold front pushing southeast from the Northwest
Mountains early this afternoon with numerous showers, isolated
thunder and bands of heavy downpours. So far, rafl staying
within the beneficial category, and is moving into areas that
desperately need the rain farther south.
Severe threat is focused over my extreme southeast counties at
mid afternoon where surface heating has primed the area and
convective temps were reached after 1 PM. Greatest chance for
severe weather is in the form of strong to locally damaging
straight line winds given very straight line hodographs,
moderate values of CAPE, and fairly weak LLVL speed shear.
DCAPE is a third lower than what we saw yesterday
afternoon/evening, but is still maximized over our southeast
counties. A MRGL outlook remains over the rest of central PA as
the front drops slowly southeastward through this evening, but
the expectation is for locally heavy rainfall to be the main
sensible wx concern, and is a welcome one for most.
Right entrance region of 110 kt upper jet stretched from NW
Ohio to Southern Quebec late this afternoon may still support a
few stronger storms across central and southeast parts of the
area, but again the focus seems to be more on hydro at this time
and relatively high FFG values for most (slightly lower over
parts of Adams/York/Lancaster which saw heavy downpours
Tuesday). PWs of nearly 2" in the SE could help feed very heavy
downpours, but fast storm motions and the high FFG (widespread
4.5"/3 hrs values) keep the threat for flash flooding low. The
MRGL risk in the Day2 ERO was collaborated with WPC, mainly in
order to keep continuity with previous forecasts.
The Heat Advisory for our SE zones remains in effect through
00z Thu with temps starting the day in the mid to upper 70s.
the lack of clouds through the overnight hours has led to some
patchy valley fog, but lack of rainfall today will be a tick in
the negative column.
The cold front slides through all but perhaps a few towns on
the MD border by 03-04Z Thursday. Thus, the SHRA should press
mainly or entirely to the S of the border well before sunrise.
Falling dewpoints should lead to a lower threat of fog, but the
temps drop right along with them. Will keep the mention of fog
from the wx grids at this point.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Thursday will mark the start of the beginning of a stretch of
fair and seasonable weather with lower humidity during the day
Thursday and all of Friday as high pressure builds from the
Great Lakes.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
On Saturday, there could still be enough moisture working into
the state from the south that a shower or two could develop over
the SE and/or ridge-and-valley region if the ridge tops can help
nudge the moisture high enough. It's only worth a 20pct chc at
this point based both on coverage and probability. This is the
only mar in an otherwise stellar weekend forecast.
During the early part of the new week, the humidity levels will
creep back up as the deep upper low over ern Canada slides a
little more to the east and the Bermuda High pushes moisture
farther to the north and into the state. The stationary
boundary to our south may struggle to move northward, so we'll
keep the increase in precip chances slow for the time being.
Overall, we will see muggy nights again by mid week and a
gradual increase in cloud cover and PoPs. By Wed, PoPs get close
to 70pct. Confidence is higher than normal in the extended
pattern. Of course, confidence is lower on the day- to- day
details. But, normal diurnal trends in convection have been
leaned on for most of the long range.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
MVFR cigs cover northwest and central PA at mid afternoon, and
are overspreading southeastern airfields this afternoon with sct
to nmrs rainshowers and isold ts. Afternoon showers and
thunderstorms will become more numerous and last into the
evening along and ahead of a cold front slowly pushing southeast
from the Great Lakes. Storms should decrease in coverage and
exit/dissipate over the south/eastern airspace between 03-06Z.
There is decent model signal for post- frontal upslope low MVFR
cigs particularly at KJST and potential IFR fog impacts at
KBFD/KIPT late tonight into early Thursday morning.
Outlook...
Thu...MVFR cigs psbl northwest 1/2; low VFR elsewhere.
Fri-Sun...AM valley fog. Otherwise, no sig wx/VFR.
&&
.CLIMATE...
The max temperature hit 100 degrees at Harrisburg yesterday
7/16. The last time KMDT hit 100 was back on July 19, 2020.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for PAZ036-056-057-
059-063>066.
&&
$$
SYNOPSIS...Lambert/DeVoir/Bowen
NEAR TERM...Lambert/DeVoir/Bowen
SHORT TERM...DeVoir/Dangelo/Bowen
LONG TERM...Dangelo
AVIATION...DeVoir
CLIMATE...Steinbugl
Office: PHI
FXUS61 KPHI 172330
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
730 PM EDT Wed Jul 17 2024
.SYNOPSIS...
A strong cold front will cross the Middle Atlantic region
tonight. It will be followed by high pressure for the end of the
week and into the weekend. Another upper system and surface
front will arrive by early next week.
&&
.NEAR TERM /THROUGH THURSDAY/...
A line of loosely organized convection has now formed across
eastern PA down into the Chesapeake Bay. While there remains
sufficient instability and shear to support some severe wind
potential, storms are beginning to struggle with some
organization, at least across these areas that already saw some
convective development earlier in the day. More abundant
instability is available across southern NJ and the Delmarva, so
storms still have an opportunity to strengthen over the next few
hours. The onset of nighttime, however, will help diminish our
severe potential gradually over the next few hours. PWAT values
over 2 inches remain across the region and continue to support
heavy downpours leading to localized flash flooding. Storms
should eventually give way to just some residual showers before
tapering off from northwest to southeast overnight as the cold
front shifts further offshore. Behind the front, light NW winds
and temperatures falling into the upper 60s to low 70s. Some
patchy fog will be possible as well.
The cold front should fully cross through the region by
Thursday morning but will begin to slow down as it passes to our
south and east. So while, the northern half of the area will
begin to see some clearing, the southern half of the area
(especially near the coast), will see cloud cover linger
throughout the day. Isolated to scattered showers and storms may
hang up along the southern Jersey shore and southern Delmarva
in the afternoon. On the bright side, this cold front will knock
down temps and humidity with highs mainly in the mid 80s.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Front will continue slowly sliding southeastward away from the
area Thursday night. A few showers or thunderstorms may linger
in the evening across southern Delaware but it should clear out
after midnight. Lows will be in the considerably more
comfortable 60s for most of the area.
Friday looks like the most pleasant day of the forecast as
Canadian high pressure briefly builds southward into the area.
Dew points will be down into the upper 50s and lower 60s with
highs only in the mid to upper 80s with mostly sunny skies and
light winds.
High pressure starts to push eastward with a lee-side trough
developing on Saturday. With winds turning back to the south,
dew points will start to creep back up. The increased moisture
plus lee side trough combined with a weak upper disturbance
working in from the southwest may be enough to bring some
scattered showers and isolated thunderstorms by afternoon,
especially west and southwest of Philly. Further north and east,
dry conditions should prevail. While dew points will be back
solidly into the 60s, highs should remain mostly in the upper
80s, so still considerably more comfortable than recent days,
but not quite as nice as Friday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The stalled front to our south will gradually creep back
northward as we head into the middle of next week. Combined with
passing upper disturbances, this should result in a general
turn towards cloudier, more showery weather, with lower temps by
mid week.
At first however, Sunday should be similar to Saturday, with
some spotty convection possible mainly west and southwest of
Philly. Dew points keep creeping up, but temps remain in the
upper 80s overall.
By Monday the increased moisture is more apparent, as dews
start to approach 70 and the front starts to push back north.
This should result in a slightly better chance of convection,
but again, not huge. Still mainly upper 80s for highs.
Tuesday and Wednesday are when conditions turn wetter, with the
front pushing back into the area with clouds and scattered
showers/t- storms becoming common. This will cause cooler temps
as well, with highs down into the mid 80s, but dew points rising
into the low-mid 70s. Will need to monitor for any locally
heavy rain risks given high moisture and slow moving front in
the vicinity, but overall this looks like a beneficial change in
the weather.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...
Tonight...Sub-VFR conditions likely with numerous to widespread
thunderstorms. Some storms may be severe with locally damaging
winds. Storms should move out after 04-06Z but sub VFR cigs
likely in their wake from fog and low stratus. Winds southwest
around 10 knots early this evening veering to northwest 5 to 10
knots overnight. Moderate confidence.
Thursday...Some lingering sub VFR cigs early in the morning with
a few lingering showers possible at MIV and ACY. Some afternoon
showers and storms possible for ACY. Otherwise VFR. NW winds
around 5 to 10 knots. Moderate confidence.
Outlook...
Thursday night thru Friday night...VFR with no significant
weather.
Saturday through Monday...mostly VFR with a slight chance of
showers and thunderstorms, mainly in the afternoon and evening
hours.
&&
.MARINE...
Small Craft Advisory in effect through Thursday morning for all
coastal waters with SSW winds 20 knots gusting up to 25 knots
with seas around 5 feet. There will also be some storms moving
over the waters that could bring locally stronger winds
potentially gusting over 40 knots.
By Thursday, winds/seas should be sub SCA but there still could
be some lingering showers and storms over the waters.
Outlook...
Thursday night through Monday...Conditions will generally be
below Small Craft Advisory criteria. Wind gusts of 15 kt or less
with wave heights of 4 feet or less. Slight chance showers and
thunderstorms, mainly in the afternoon and evening hours.
Rip currents...
For Thursday, winds will turn more offshore out of the west to
northwest and decrease to around 10 mph. Wave heights will
mainly be around 1-2 feet in Delaware and 2-3 feet in New
Jersey with a 7-8 second period. As the winds should be weaker
and directed offshore across the region, the risk for the
development of dangerous and life threatening rip currents is
forecast to be LOW at the DE beaches and MODERATE at the NJ
shore on Thursday.
For Friday, winds will become northeasterly but remain around
10 mph. Wave heights will mainly remain around 1-2 feet in
Delaware and 2-3 feet in New Jersey with a 7-8 second period.
Therefore, the risk for the development of dangerous and life
threatening rip currents is forecast to be LOW at the DE beaches
and MODERATE at the NJ shore on Friday.
For specific beach forecasts, visit weather.gov/beach/phi
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Excessive Heat Warning until 8 PM EDT this evening for
PAZ060>062-070-071-101>106.
Heat Advisory until 8 PM EDT this evening for PAZ054-055.
NJ...Excessive Heat Warning until 8 PM EDT this evening for
NJZ007>010-012-013-015>023-027.
Heat Advisory until 8 PM EDT this evening for NJZ001-014.
Air Quality Alert until 11 PM EDT this evening for NJZ012>015-
017>019.
DE...Excessive Heat Warning until 8 PM EDT this evening for
DEZ001>003.
Heat Advisory until 8 PM EDT this evening for DEZ004.
MD...Excessive Heat Warning until 8 PM EDT this evening for MDZ012-
015-019-020.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for ANZ450>455.
&&
$$
SYNOPSIS...RCM
NEAR TERM...MJL
SHORT TERM...RCM
LONG TERM...RCM
AVIATION...MJL/RCM
MARINE...MJL/RCM
Office: PBZ
FXUS61 KPBZ 172215 AAC
AFDPBZ
Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
615 PM EDT Wed Jul 17 2024
.SYNOPSIS...
Showers and thunderstorms will continue through the evening with
a crossing front. High pressure will return dry conditions and
seasonable temperatures the remainder of the week and into the
weekend.
&&
.NEAR TERM /THROUGH THURSDAY/...
KEY MESSAGES:
- Showers and storms expected along and ahead of a cold front
crossing through this evening.
- A small threat of strong to severe wind gusts remains, as does
the risk of isolated flooding, although both threats will
decrease with time.
__________________________________________________________________
Update focused on minor adjustments over the next several hours
based on radar and observation trends. Outflow moving out ahead from
the main convective line has helped to sap its strength to some
degree, and the overall environment for strong wind gusts
remains poor with lackluster lapse rates and unfavorable DCAPE
values. An isolated strong to severe gust or two cannot be
totally ruled out, mainly in eastern Ohio where slightly more
favorable MLCAPE/DCAPE is located. Also, despite the lingering
high PWAT values, flooding concerns are lessening with time as
well as the overall line becomes more progressive, with urban
areas most likely to see any impact from localized 1-2"/hour
rainfall rates. The cold front itself is just now crossing into
the northwest corner of the CWA, and will continue to slowly
progress to the southeast through the evening.
Once the main line departs the region by 01Z/02Z, a few
scattered showers may linger ahead of the crossing boundary,
which should exit the region shortly after midnight. Partial
clearing is expected overnight, although stratocumulus may
linger particularly in the ridges. Patchy fog cannot be ruled
out as well, although ongoing mixing may limit its extent to
some degree. Dewpoints and temperatures will drop off through
the night as well, although a noticeable difference will likely
wait until daytime mixing on Thursday.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
KEY MESSAGES:
- Dry and cool conditions Thursday with temperatures moderating
to near normal Friday.
_________________________________________________________________
Dry and seasonable conditions are expected as surface high
pressure builds eastward over the region. Low- level cold and
dry advection will keep temperatures near or even a few degrees
below average Thursday and Thursday night with valley fog
chances.
Stout mixing into the day on Friday under high pressure will
result in temperatures near normal, and fairly low humidity.
This will leave the area feeling comfortable for the last day of
the work-week.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
KEY MESSAGES:
- Mainly dry weekend with high pressure in control.
- Precipitation chances return for the start of the week.
-------------------------------------------------------------------
Digging trough over the central Plains may lead to a slight
increase in 500mb heights Saturday/Sunday. This may also bring
some moisture return to the upper Ohio Valley but at this time,
precipitation looks to be limited to the ridges south and east
of PGH. With rising heights, temperatures will trend higher to
slightly above normal. Strengthening southwesterly flow will
return precipitation chances into early next week ahead of
approaching low pressure.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
Line of showers and storms will exit to the south of the region
early in the forecast period. A return to VFR conditions is then
expected.
The biggest question overnight will be the formation of fog. The
combination of clear to partly cloud skies and the rain
this afternoon/evening, is a good setup for fog. However, drier
air will be spreading southward overnight behind an exiting
cold front. Latest probs show a 50-70% chance of MVFR fog
generally in the ridges and some of the river valleys. Seeing
the same probs for IFR vis as well. Will mention fog at all
ports overnight and bring the forecast down to IFR in the
eastern ports and those near the rivers.
Fog will burn off quickly after sunrise and a return to VFR is
expected at all ports. Sct CU should develop with daytime
heating on Thursday.
.Outlook...
VFR is expected Friday through Sunday under building high
pressure.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...34/CL
NEAR TERM...34
SHORT TERM...34
LONG TERM...34/88
AVIATION...22
