Excessive Heat Warning 5, NWS Philadelphia/Mount Holly

987 
WWUS71 KPHI 022009
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
409 PM EDT Fri Aug 2 2024

DEZ001-NJZ010-012-013-015-017>019-PAZ070-071-104-106-030000-
/O.CON.KPHI.EH.W.0005.000000T0000Z-240803T0000Z/
New Castle-Somerset-Middlesex-Western Monmouth-Mercer-Gloucester-
Camden-Northwestern Burlington-Delaware-Philadelphia-Eastern
Montgomery-Lower Bucks-
Including the cities of Mount Holly, New Brunswick, Media,
Glassboro, Lansdale, Wilmington, Philadelphia, Somerville,
Trenton, Camden, Norristown, Morrisville, Doylestown, Freehold,
Moorestown, and Cherry Hill
409 PM EDT Fri Aug 2 2024

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS 
EVENING...

* WHAT...Dangerously hot conditions with heat index values up to 108.

* WHERE...Portions of northern Delaware, central, northern, and 
  southern New Jersey, and southeast Pennsylvania.

* WHEN...Until 8 PM EDT this evening.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

* ADDITIONAL DETAILS...Any showers and thunderstorms will bring 
  relief from the excessive heat.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of 
the sun, and check up on relatives and neighbors.

Do not leave young children and pets in unattended vehicles. Car 
interiors will reach lethal temperatures in a matter of minutes.

To reduce risk during outdoor work, the Occupational Safety and 
Health Administration recommends scheduling frequent rest breaks in 
shaded or air conditioned environments. Anyone overcome by heat 
should be moved to a cool and shaded location. Heat stroke is an 
emergency! Call 9 1 1.

&&

$$

DEZ002-003-MDZ012-015-019-020-NJZ016-021-030000-
/O.CON.KPHI.EH.W.0005.000000T0000Z-240803T0000Z/
Kent-Inland Sussex-Kent MD-Queen Annes-Talbot-Caroline-Salem-
Cumberland-
Including the cities of Dover, Easton, Centreville, Pennsville,
Denton, Millville, Georgetown, and Chestertown
409 PM EDT Fri Aug 2 2024

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS 
EVENING...

* WHAT...Dangerously hot conditions with heat index values up to 108.

* WHERE...In Delaware, Kent and Inland Sussex Counties. In Maryland, 
  Caroline, Kent MD, Queen Annes, and Talbot Counties. In New 
  Jersey, Cumberland and Salem Counties.

* WHEN...Until 8 PM EDT this evening.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

* ADDITIONAL DETAILS...Any showers and thunderstorms will bring 
  relief from the excessive heat.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of 
the sun, and check up on relatives and neighbors.

Do not leave young children and pets in unattended vehicles. Car 
interiors will reach lethal temperatures in a matter of minutes.

To reduce risk during outdoor work, the Occupational Safety and 
Health Administration recommends scheduling frequent rest breaks in 
shaded or air conditioned environments. Anyone overcome by heat 
should be moved to a cool and shaded location. Heat stroke is an 
emergency! Call 9 1 1.

&&

$$

NJZ001-007>009-PAZ060>062-105-030000-
/O.CON.KPHI.HT.Y.0008.000000T0000Z-240803T0000Z/
Sussex-Warren-Morris-Hunterdon-Berks-Lehigh-Northampton-Upper
Bucks-
Including the cities of Washington, Chalfont, Easton, Morristown,
Newton, Reading, Flemington, Bethlehem, Perkasie, and Allentown
409 PM EDT Fri Aug 2 2024

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING...

* WHAT...Heat index values up to 100.

* WHERE...In New Jersey, Morris, Sussex, Warren, and Hunterdon 
  Counties. In Pennsylvania, Berks, Lehigh, Northampton, and Upper 
  Bucks Counties.

* WHEN...Until 8 PM EDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses.

* ADDITIONAL DETAILS...Showers and thunderstorms have brought relief 
  from the excessive heat to many areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of 
the sun, and check up on relatives and neighbors.

To reduce risk during outdoor work, the Occupational Safety and 
Health Administration recommends scheduling frequent rest breaks in 
shaded or air conditioned environments. Anyone overcome by heat 
should be moved to a cool and shaded location. Heat stroke is an 
emergency! Call 9 1 1.

&&

$$

NJZ020-027-PAZ101>103-030000-
/O.CON.KPHI.HT.Y.0008.000000T0000Z-240803T0000Z/
Ocean-Southeastern Burlington-Western Chester-Eastern Chester-
Western Montgomery-
Including the cities of Jackson, West Chester, Kennett Square,
Honey Brook, Pottstown, Wharton State Forest, Collegeville, and
Oxford
409 PM EDT Fri Aug 2 2024

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING...

* WHAT...Heat index values up to 103.

* WHERE...In New Jersey, Ocean and Southeastern Burlington Counties. 
  In Pennsylvania, Eastern Chester, Western Chester, and Western 
  Montgomery Counties.

* WHEN...Until 8 PM EDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses.

* ADDITIONAL DETAILS...Some showers and thunderstorms will bring 
  relief from the excessive heat.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of 
the sun, and check up on relatives and neighbors.

To reduce risk during outdoor work, the Occupational Safety and 
Health Administration recommends scheduling frequent rest breaks in 
shaded or air conditioned environments. Anyone overcome by heat 
should be moved to a cool and shaded location. Heat stroke is an 
emergency! Call 9 1 1.

&&

$$

NJZ022-023-030000-
/O.CON.KPHI.HT.Y.0008.000000T0000Z-240803T0000Z/
Atlantic-Cape May-
Including the cities of Hammonton and Cape May Court House
409 PM EDT Fri Aug 2 2024

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING...

* WHAT...Heat index values up to 103.

* WHERE...Atlantic and Cape May Counties.

* WHEN...Until 8 PM EDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of 
the sun, and check up on relatives and neighbors.

To reduce risk during outdoor work, the Occupational Safety and 
Health Administration recommends scheduling frequent rest breaks in 
shaded or air conditioned environments. Anyone overcome by heat 
should be moved to a cool and shaded location. Heat stroke is an 
emergency! Call 9 1 1.

&&

$$

417 
WWUS71 KPHI 030005
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
805 PM EDT Fri Aug 2 2024

DEZ001>003-MDZ012-015-019-020-NJZ010-012-013-015>019-021-PAZ070-071-
104-106-030115-
/O.EXP.KPHI.EH.W.0005.000000T0000Z-240803T0000Z/
New Castle-Kent-Inland Sussex-Kent MD-Queen Annes-Talbot-Caroline-
Somerset-Middlesex-Western Monmouth-Mercer-Salem-Gloucester-
Camden-Northwestern Burlington-Cumberland-Delaware-Philadelphia-
Eastern Montgomery-Lower Bucks-
Including the cities of Georgetown, Wilmington, Philadelphia,
Mount Holly, Centreville, Moorestown, Cherry Hill, Easton, Dover,
Pennsville, Somerville, Trenton, Freehold, Doylestown,
Morrisville, Lansdale, Camden, Chestertown, Denton, New
Brunswick, Glassboro, Media, Norristown, and Millville
805 PM EDT Fri Aug 2 2024

...EXCESSIVE HEAT WARNING HAS EXPIRED...

$$

NJZ001-007>009-020-022-023-027-PAZ060>062-101>103-105-030115-
/O.EXP.KPHI.HT.Y.0008.000000T0000Z-240803T0000Z/
Sussex-Warren-Morris-Hunterdon-Ocean-Atlantic-Cape May-
Southeastern Burlington-Berks-Lehigh-Northampton-Western Chester-
Eastern Chester-Western Montgomery-Upper Bucks-
Including the cities of Oxford, West Chester, Kennett Square,
Reading, Easton, Cape May Court House, Jackson, Washington,
Pottstown, Honey Brook, Hammonton, Newton, Morristown, Wharton
State Forest, Chalfont, Bethlehem, Collegeville, Perkasie,
Flemington, and Allentown
805 PM EDT Fri Aug 2 2024

...HEAT ADVISORY HAS EXPIRED...

Temperatures have cooled as we head into the evening and while 
another hot day is expected for Saturday, conditions should remain 
below Advisory criteria.

$$

Fitzsimmons

Area Forecast Discussion
National Weather Service Mount Holly NJ
401 AM EDT Fri Aug 2 2024

.SYNOPSIS...
Hot and humid conditions expected through the weekend high
pressure eventually gives way to a slow moving cold front over
the weekend. High pressure builds again to start the week before
another cold front then settles across our region Wednesday
into Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Storms from earlier have diminished due to the loss of daytime
heating. However well to our west there is some convection over
Ohio moving into western PA. This should weaken and start to
fall apart as it moves east but still can't rule out a few
showers or isolated storms making there way into eastern PA by
later tonight. But POPs are only around 20 percent here.
Otherwise it will be a warm and sticky night with lows in the
70s across the region and dew points in the upper 60s to low
70s.

Our attention then turns to the next approaching wave on Friday
which will bring increases chances for scattered to numerous showers
and thunderstorms Friday afternoon. An upper-level trough will be
deepening to our west,  making the overall upper-level synoptic
setup more favorable. This will also increase southwesterly flow
aloft, drawing even more moisture into the region. PWATs are
forecasted to increase to 2-2.5 inches across much of the area. With
the more favorable dynamics and higher PWATs, there will be an
increased risk for localized flooding with heavy downpours from any
thunderstorms. However, model soundings show that storm motions
should be sufficient to keep storms from sitting over one place too
long. Additionally, some CAM guidance indicates that the convection
may take the form of a semi-organized cluster or line along a
surface trough moving through the region. If this scenario occurs,
it would increase the risk for damaging wind gusts across the area.
Model soundings also indicate an inverted V with strong low-level
lapse rates so localized downbursts may still be possible even if
convection is more scattered. As a result, a Marginal Risk (1 out of
5) for severe weather is in place across the area and a Marginal to
Slight risk (1 out of 4 and 2 out of 4) for excessive rainfall
mainly for the area near and northwest of the I-95 corridor, with the
Slight risk limited, mainly near and north of the I-78 corridor.

Otherwise, with the aforementioned increasing moisture, heat
indicies will once again be near or above 100 degrees across the
area. This will be despite slightly cooler temperatures on Friday
compared to today, with highs mainly in the low-mid 90s. No changes
were made to the Heat Advisory in place as a result of the
continued high heat indicies.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
An upper-level trough shifts across the Great Lakes and Ohio Valley
Friday night into Saturday, then gets to our area Saturday night.
This system will bring an increase in showers and thunderstorms
within a very moist air mass. Heat will again be the concern
initially as the forecast is for temps to quickly warm into the
upper 80s to low 90s with high humidity. The question will be how
high do the temps actually get with respect to the need for a heat
advisory again for Saturday. Looking at the ensemble guidance there
are roughly two clusters in the guidance. The first cluster has more
of a weaker trough, with cooler temps as the southerly flow isn't
quite as strong.  The second cluster within the ensembles shows a
sharper trough with enhanced southerly winds. In the second
scenario, temps from the GEFS suggest that 2m temps have a 75%
chance of exceeding 90 degrees whereas in more of the weaker wave
system from the ENS and the GEPS, the more likely scenario is
topping out in the upper 80s.

Using the location of the current trough as a proxy for tomorrow,
the GFS has initialized the wave a bit weaker today and the EC
matches quite well. So I've trended the forecast more towards the
ENS/GEPS solution for tomorrow but we'll continue to monitor.

Concerning the storms for tomorrow, with a trend towards the
EPS/GEPS solution, I've opted to keep that going for convection.
That leads to strong moisture advection over the region ample
instability. Forcing will be sufficient and lapse rates in the
low levels while not as steep as it could be, will still be
ample strong enough to generate downburst potential through the
day. In addition, with pwats forecast to be in the 90th
percentile, and warm cloud depths close to 12,000 ft, I
anticipate the rainstorms to be highly efficient and have the
potential to cause flash flooding.

For Sunday both the heat and convective potential will be more mild
as cloud cover and lower temps should be prevail however as the
previous shift mentioned, with high humidity it will still feel
fairly unpleasant outside.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Summary...The hot and humid conditions ease during the week, however
chances for some showers and thunderstorms remain.

Synoptic Overview...An upper-level trough across eastern Canada will
extend down across the Great Lakes and Northeast with our area being
on the southerly periphery. This trough may shift far enough
northeast Wednesday and Thursday to result in more of a zonal flow,
however a west-northwest flow aloft is forecast to be in place. As
shortwaves slide east or east-southeast within the mid level flow,
at the surface a front will try and settle into our area from the
north Tuesday although this will be more parallel to the flow aloft.
A weak low may track nearby Wednesday into Thursday, pulling a cold
front across our area.

For Monday and Tuesday...As our region remains along the southern
periphery of an upper-level trough, a weak cold front nearly stalls
just offshore. The cooling effect from this trough looks delayed
therefore Monday is forecast to be hot with highs expected to be in
the upper 80s to low 90s for much of the area. Some drier air
however is forecast to advect in from northwest to southeast and
therefore while still humid the heat indices are forecast to be
below Heat Advisory criteria. The gradual drying may limit
convection especially as we may be between weak systems, however
some isolated mainly diurnally driven convection cannot be ruled out
mainly north/west of I-95. Some more influence of the trough is
forecast on Tuesday along with a cold front approaching from the
west. Some additional cloudiness along with some cooling aloft
should translate to lower temperatures. Dew points are forecast to
be high enough for a humid feel for much of the area, however not to
excessive levels. The overall forcing looks week given not a strong
look to the trough aloft and therefore the chances for convection
Tuesday also looks to be isolated at this point.

For Wednesday and Thursday...The flow aloft may turn a bit more
zonal, and therefore a cold front moving through may tend to do so
on the slower side. Some shortwaves however embedded within this
flow may enhance the local lift at least some and provide the
chances for some showers and thunderstorms. Given the uncertainty
with the details, kept PoPs in the lower chance range (30 percent).
High temperatures are currently forecast to be at or even a little
below average.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of tonight (through 12Z)...Mainly VFR except some patchy
shallow mist/fog. Winds diminishing to 5 kts or less, favoring
a southerly direction. Moderate confidence.

Friday...Prevailing VFR conditions. Chances for showers and storms
increase in the afternoon, particularly after 18Z, which may result
in times of sub-VFR conditions. Southerly winds around 5-10 knots,
higher gusts possible in the vicinity of any thunderstorms. High
confidence in prevailing conditions.

Outlook...

Saturday through Sunday...Scattered showers with embedded
thunderstorms will have the potential to impact the terminals
resulting in heavy rain, reduced visibilities, and locally
strong wind gusts on Saturday. Showers will still be possible on
Sunday although the intensity should be weaker.

Monday and Tuesday...Mostly VFR with a chance for a few mostly
afternoon and evening showers and thunderstorms.

&&

.MARINE...
Conditions are forecast to remain below advisory conditions through
Friday. Southerly winds 10-15 kts, with some gusts near 20 kts
possible in the afternoon and evening today and Friday. Seas 2-3
feet. An isolated thunderstorm is possible in the afternoon both
today and Friday as well, otherwise fair weather.

Outlook...

Friday night through Tuesday...The conditions are anticipated to be
mostly below Small Craft Advisory criteria. However, the seas may
build to 5 feet on the ocean zones late Saturday into Sunday. Some
stronger thunderstorms are possible especially Friday evening and
then again both Saturday and Sunday afternoons and evenings.

Rip Currents...

For Friday, there is a LOW risk for the development of dangerous rip
currents for both the Jersey Shore and for the Delaware Beaches.
South winds will average 10 to 15 mph. Wave heights in the surf zone
will be 2 feet with a period around 7 seconds.

For Saturday, South to southwest winds increase to 15 to 20 mph with
waves in the surf zone increasing to around 3 feet. We will also be
within a day of the new Moon. For these reasons, will forecast a
MODERATE risk for the development of dangerous rip currents for the
NJ shore with the exception of Monmouth County where the risk will
be LOW. The Delaware Beaches will also have a LOW risk for
dangerous rip currents.

For specific beach forecasts, visit weather.gov/beach/phi

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory until 8 PM EDT this evening for PAZ060>062-070-
     071-101>106.
NJ...Heat Advisory until 8 PM EDT this evening for NJZ007>010-012-
     013-015-017>020-027.
     Heat Advisory from 10 AM this morning to 8 PM EDT this evening
     for NJZ016-021-022.
DE...Heat Advisory until 8 PM EDT this evening for DEZ001.
     Heat Advisory from 10 AM this morning to 8 PM EDT this evening
     for DEZ002-003.
MD...Heat Advisory from 10 AM this morning to 8 PM EDT this evening
     for MDZ012-015-019-020.
MARINE...None.

&&

SYNOPSIS...Deal/Gorse
NEAR TERM...MJL
SHORT TERM...Deal
LONG TERM...Deal/Gorse
AVIATION...Deal/MJL
MARINE...Deal/Gorse/MJL