Heat Advisory 6, NWS Philadelphia/Mount Holly

815 
WWUS71 KPHI 302248
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
648 PM EDT Thu Jul 30 2020

DEZ001>004-MDZ008-012-015-019-020-NJZ016>018-020>027-310000-
/O.CAN.KPHI.HT.Y.0006.000000T0000Z-200730T2300Z/
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Salem-Gloucester-Camden-Ocean-
Cumberland-Atlantic-Cape May-Atlantic Coastal Cape May-
Coastal Atlantic-Coastal Ocean-Southeastern Burlington-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Elkton, Chestertown, Centreville, Easton, Denton,
Pennsville, Glassboro, Camden, Cherry Hill, Jackson, Millville, 
Hammonton, Cape May Court House, Ocean City, Atlantic City, 
Long Beach Island, and Wharton State Forest
648 PM EDT Thu Jul 30 2020

...HEAT ADVISORY IS CANCELLED...

$$

Area Forecast Discussion
National Weather Service Mount Holly NJ
1009 AM EDT Thu Jul 30 2020

.SYNOPSIS...
A warm front will lift into the region today and then stall over the
region into tonight before sinking just to our south into Friday.
This front will then gradually lift back northward through the area
this weekend as several weak waves of low pressure move through the
eastern Great Lakes. A mid and upper level trough will then meander
over the east for much of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
No big changes to the forecast so far today. Mostly high level
clouds will continue to affect the area for much of the day and into
the afternoon hours. It will be another hot and muggy day with
temperatures 5-10 degrees above normal, but as dewpoints mix some
through the day, heat index values are forecast to remain just below
Heat Advisory levels for most places. The first half of the day
through the early afternoon will be dry, but as we move into
the middle to late afternoon, a few showers and thunderstorms
will be possible. Instability will be building with MLCAPE
exceeding 2000 J/kg into the afternoon, so a few isolated
showers or thunderstorms are possible into the afternoon, but
coverage should remain limited. Any more robust cells may be
capable of producing strong to locally damaging winds late this
afternoon and evening.

A frontal boundary will approach the area from the north and begin
pushing through into the late afternoon and evening, when chances
for thunderstorms will increase substantially. The greatest chance
for storms will be generally across Delmarva and southern NJ and up
to around the Philly metro where the greatest instability will
reside. Deep layer shear isn't particularly poor, around 25-30 kts,
so there could be a bit more organized nature to convection into the
late evening and overnight period. DCAPE appears to be up to around
900 J/kg, so the stronger cells could result in gusty to perhaps
locally damaging winds. Lapse rates are poor though, so not
expecting much of any hail in this environment.

Deep layer shear and propagation vectors will be nearly parallel to
the initiating boundary moving very slowly southward, so it's
probable that we'll see some training of convection. Guidance
indicates that PWs will rise well over 2" in the vicinity and south
of the boundary. Therefore, expecting a heavy rain threat also be
present in addition to the isolated severe threat. With that said,
antecedent dry conditions and high flash flood guidance suggest any
flash flooding treat would be fairly isolated at best, so we've
opted against issuing a Flash Flood Watch at this time.

&&

.SHORT TERM /FRIDAY/...
The boundary will stall near the southern portion of the area into
Friday and lingering instability will keep chances of convection
especially across far southern NJ and Delmarva through Friday
afternoon. The rest of the area looks mostly dry for Friday outside
of perhaps a few stray showers or storms up north. PWs will remain
high though, so heavy rain will remain a threat with any of the
lingering convection across Delmarva and southern NJ. Chances of
convection will end quickly into the late afternoon and evening
hours Friday.

Friday will likely be the coolest day in a while for most with
forecast highs in the low to mid 80s and mostly cloudy skies
providing a break from the heat.  Unfortunately though, it'll still
be muggy with dewpoints remaining within a few degrees of 70. Skies
will begin clearing across the north portion of the area into the
late afternoon and evening.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Friday night through Sunday...

A weak frontal boundary will sit to our south Friday night and this
should keep most of the area dry with showers mainly to our south
towards Virginia. However by Saturday this boundary will start to
move back to the north as an upper level trough and weak low
pressure try to organize near the Gulf Coast. This will start to
bring in some increasing chances for showers/storms by Saturday
afternoon mainly over Delmarva, SE PA, and far southern NJ. However
it doesn't look to be a washout. Expect seasonable temperatures and
humidity levels with variable cloud cover as highs will be mainly in
the 80s to around 90 over the urban corridor.

For Saturday night, the aformentioned front should lift north
into the region as the upper trough deepens to our west with
weak surface low pressure moving north towards Ohio.
Shower/storms may become more widespread across the area by this
time as a result and also could include heavy downpours. Dew
points will also be on the rise so it will be a warm, muggy
night with lows mainly in the upper 60s to mid 70s.

Sunday looks to be hot and humid with a southerly flow in the wake
of the frontal passage. Dew points look to be back into the 70s for
much of the region. As an upper level trough continues to take shape
over the midwest this will result in a fairly deep moisture feed so
expect fairly widespread showers/storms to develop by the
afternoon...especially N/W of the I-95 corridor. While it's early to
get into specifics, PWATs around 2 inches along with ML CAPEs around
1000-2000 j/kg combined with modest shear could result in both the
potential for heavy rainfall and even some severe weather.

Sunday night through Wednesday...

The overall pattern looks to remain muggy and unsettled through at
least the first part of next week as an upper level trough remains
centered to our west over the Great Lakes into the midwestern
States. This will keep the region in a moist southerly flow. That
said the details of the forecast remain uncertain with one of the
wildcards being the track of Isaias as it could track near the
region either Monday or Tuesday. Again though, since this is several
days out this is far from a certainty. Nevertheless, given that
there should be abundant moisture around either way we keep at least
high chance POPs in the forecast through Tuesday. High temperatures
look to generally be around seasonal but dew points and RHs will be
quite high.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Today...Prevailing VFR with scattered showers and thunderstorms
developing after 21Z. Winds southwesterly around 5-10 kts. High
confidence.

Tonight...Widespread showers and thunderstorms expected for much of
the I-95 corridor and south/east, especially after 03Z. While VFR is
expected to prevail initially, it is probable that convection
will lower ceiling and visibility restrictions, especially after
06Z. Winds variable around 5 kts or less, but generally
favoring a northerly direction outside of convection. Confidence
on timing and placement is low, but confidence on showers and
storms occurring is high.

Outlook...

Friday...Lingering sub-VFR restrictions will improve slowly
around 15-18Z. Scattered showers or thunderstorms will remain
possible at MIV/ACY/ILG/PHL through 00Z. Winds northeasterly
around 5 kts. Moderate confidence.

Friday night - Saturday...Mainly VFR. Occasional showers or
thunderstorms possible especially at MIV/ACY/ILG with localized
sub-VFR conditions. Winds initially light and variable becoming
E/SE 5-8 knots on Saturday. Moderate confidence.

Sunday...Prevailing VFR. Widespread showers and thunderstorms will
locally reduce restrictions. Winds southerly around 10 kts with
higher gusts possible. Moderate confidence.

Sunday night and Monday...Prevailing VFR. Showers and thunderstorms
possible, especially south, on Monday. Low confidence.

&&

.MARINE...
Conditions are forecast to remain below advisory criteria through
the period. Showers and thunderstorms will develop into the evening
hours and last through much of the overnight period. Scattered
showers and thunderstorms remain possible into the day Friday with
below advisory criteria expected otherwise. Seas 2-3 feet on the
ocean waters and 1-2 feet on Delaware Bay. Winds will be southerly
on Thursday around 10-15 kts then will become northeasterly early
Friday around 5-10 kts.

Outlook...

Conditions are forecast to remain below advisory criteria
Friday night through most of the weekend. However a developing
tropical system well south of the area may bring seas exceeding
5 feet by Monday and Tuesday. Scattered showers and
thunderstorms possible each day, especially Sunday.

Rip Currents...

There is a low risk for the development of dangerous rip currents
through Friday.

&&

.EQUIPMENT...
The NOAA Weather Radio All-Hazards broadcast from Hibernia Park,
Pennsylvania (Station WNG-704) remains off the air, but repairs are
anticipated later this week.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

Synopsis...Fitzsimmons
Near Term...Robertson/Staarmann
Short Term...Staarmann
Long Term...Fitzsimmons
Aviation...Fitzsimmons/Robertson/Staarmann
Marine...Fitzsimmons/Staarmann
Equipment...WFO PHI

Hazardous Weather Outlook
National Weather Service Mount Holly NJ
345 AM EDT Thu Jul 30 2020

NJZ001-007-008-PAZ054-055-061-062-310745-
Sussex-Warren-Morris-Carbon-Monroe-Lehigh-Northampton-
345 AM EDT Thu Jul 30 2020

This Hazardous Weather Outlook is for northern New Jersey, east
central Pennsylvania and northeast Pennsylvania.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

ANZ430-431-450>455-310745-
Delaware Bay waters north of East Point NJ to Slaughter Beach DE-
Delaware Bay waters south of East Point NJ to Slaughter Beach DE-
Coastal waters from Sandy Hook to Manasquan Inlet NJ out 20 nm-
Coastal waters from Manasquan Inlet to Little Egg Inlet NJ out 20 nm-
Coastal waters from Little Egg Inlet to Great Egg Inlet NJ out 20 nm-
Coastal waters from Great Egg Inlet to Cape May NJ out 20 nm-
Coastal waters from Cape May NJ to Cape Henlopen DE out 20 nm-
Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm-
345 AM EDT Thu Jul 30 2020

This Hazardous Weather Outlook is for Atlantic coastal waters and
Delaware Bay Waters.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

DEZ001>004-MDZ008-012-015-019-020-NJZ009-010-012>027-PAZ060-070-071-
101>106-310745-
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Atlantic Coastal Cape May-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Berks-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
345 AM EDT Thu Jul 30 2020

This Hazardous Weather Outlook is for central Delaware, northern
Delaware, southern Delaware, northeast Maryland, central New
Jersey, northern New Jersey, northwest New Jersey, southern New
Jersey, east central Pennsylvania and southeast Pennsylvania.

.DAY ONE...Today and tonight.

Showers and thunderstorms this evening and overnight will be capable
of producing heavy rainfall which may lead to localized flash
flooding.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

There is a low probability for widespread hazardous weather.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Staarmann