Alert archive / New Jersey / Dense Fog Advisories in 2017

Dense Fog Advisory 3, NWS Philadelphia/Mount Holly

February 23, 20174 states

NWS Philadelphia/Mount Holly issued this dense fog advisory at Feb 23, 2017, 2:58 AM EST for 4 states. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Feb 23, 2017, 2:58 AM EST (07:58 UTC)
Expired
Feb 23, 2017, 10:00 AM EST
In force
7 hr
Issued by
NWS Philadelphia/Mount Holly
All 28 counties

Kent County, DE, New Castle County, DE, Caroline County, MD, Cecil County, MD, Kent County, MD, Queen Anne's County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 69 km from the middle of the area, began a volume at 08:02 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 8.0 hours before the alert went out and 215 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 00:00Z on 2017-02-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2017-02-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

757 
WWUS71 KPHI 230758
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
258 AM EST Thu Feb 23 2017

DEZ001-002-MDZ008-012-015-020-NJZ013>027-PAZ070-071-101>106-
231500-
/O.NEW.KPHI.FG.Y.0003.170223T0758Z-170223T1500Z/
New Castle-Kent-Cecil-Kent MD-Queen Annes-Caroline-
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-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Dover, Elkton, Chestertown, 
Centreville, Denton, Freehold, Sandy Hook, Trenton, Pennsville, 
Glassboro, Camden, Cherry Hill, Moorestown, Mount Holly, Jackson,
Millville, Hammonton, Cape May Court House, Ocean City, 
Atlantic City, Long Beach Island, Wharton State Forest, Media, 
Philadelphia, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
258 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM EST THIS MORNING...

The National Weather Service in Mount Holly has issued a Dense 
Fog Advisory. It is in effect until 10:00 AM this morning.

* LOCATIONS...Northeastern Maryland, northern and central 
  Delaware, southeastern Pennsylvania, and central and southern 
  New Jersey.

* VISIBILITY...Reduced to less than a quarter mile in spots.

* TIMING...The areas of dense fog will persist until mid morning.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be 
sure to leave plenty of distance between your vehicle and the one 
ahead of you.

&&

$$

Iovino
5 follow-up statements
391 
WWUS71 KPHI 231005
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
505 AM EST Thu Feb 23 2017

NJZ009-010-012-PAZ060-231500-
/O.EXA.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
Hunterdon-Somerset-Middlesex-Berks-
Including the cities of Flemington, Somerville, New Brunswick, 
and Reading
505 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM EST THIS MORNING...

The National Weather Service in Mount Holly has issued a Dense
Fog Advisory. It is in effect until 10:00 AM this morning.

* LOCATIONS...Northeastern Maryland, northern and central 
  Delaware, southeastern Pennsylvania, and central and southern 
  New Jersey.

* VISIBILITY...Reduced to less than a quarter mile in spots.

* TIMING...The areas of dense fog will persist until mid morning.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be
sure to leave plenty of distance between your vehicle and the one
ahead of you.

&&

$$

DEZ001-002-MDZ008-012-015-020-NJZ013>027-PAZ070-071-101>106-
231500-
/O.CON.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
New Castle-Kent-Cecil-Kent MD-Queen Annes-Caroline-
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-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Dover, Elkton, Chestertown, 
Centreville, Denton, Freehold, Sandy Hook, Trenton, Pennsville, 
Glassboro, Camden, Cherry Hill, Moorestown, Mount Holly, Jackson,
Millville, Hammonton, Cape May Court House, Ocean City, 
Atlantic City, Long Beach Island, Wharton State Forest, Media, 
Philadelphia, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
505 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM EST THIS
MORNING...

* LOCATIONS...Northeastern Maryland, northern and central 
  Delaware, southeastern Pennsylvania, and central and southern 
  New Jersey.

* VISIBILITY...Reduced to less than a quarter mile in spots.

* TIMING...The areas of dense fog will persist until mid morning.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be
sure to leave plenty of distance between your vehicle and the one
ahead of you.

&&

$$

Iovino
023 
WWUS71 KPHI 231125
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
625 AM EST Thu Feb 23 2017

DEZ002-MDZ015-020-231230-
/O.CAN.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
Kent-Queen Annes-Caroline-
Including the cities of Dover, Centreville, and Denton
625 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IS CANCELLED...

The National Weather Service in Mount Holly has cancelled the 
Dense Fog Advisory for Kent County in Delaware, and for Queen 
Anne's County and Talbot County in Maryland.

$$

DEZ001-MDZ008-012-NJZ009-010-012>027-PAZ060-070-071-101>106-
231500-
/O.CON.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
New Castle-Cecil-Kent MD-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-
Including the cities of Wilmington, Elkton, Chestertown, 
Flemington, Somerville, New Brunswick, Freehold, Sandy Hook, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Ocean City, Atlantic City, Long Beach Island, 
Wharton State Forest, Reading, Media, Philadelphia, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
625 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM EST THIS
MORNING...

* LOCATIONS...Northeastern Maryland, northern Delaware, 
  southeastern Pennsylvania, and central and southern New Jersey.

* VISIBILITY...Reduced to less than a quarter mile in spots.

* TIMING...The areas of dense fog will persist until mid morning.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be 
sure to leave plenty of distance between your vehicle and the one 
ahead of you.

&&

$$

Iovino
583 
WWUS71 KPHI 231128
NPWPHI

URGENT - WEATHER MESSAGE...CORRECTED
National Weather Service Mount Holly NJ
628 AM EST Thu Feb 23 2017

DEZ002-MDZ015-020-231230-
/O.COR.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
Kent-Queen Annes-Caroline-
Including the cities of Dover, Centreville, and Denton
628 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IS CANCELLED...

The National Weather Service in Mount Holly has cancelled the 
Dense Fog Advisory for Kent County in Delaware, and for Queen 
Anne's County and Caroline County in Maryland.

$$

DEZ001-MDZ008-012-NJZ009-010-012>027-PAZ060-070-071-101>106-
231500-
/O.CON.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
New Castle-Cecil-Kent MD-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-
Including the cities of Wilmington, Elkton, Chestertown, 
Flemington, Somerville, New Brunswick, Freehold, Sandy Hook, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Ocean City, Atlantic City, Long Beach Island, 
Wharton State Forest, Reading, Media, Philadelphia, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
628 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM EST THIS
MORNING...

* LOCATIONS...Northeastern Maryland, northern Delaware, 
  southeastern Pennsylvania, and central and southern New Jersey.

* VISIBILITY...Reduced to less than a quarter mile in spots.

* TIMING...The areas of dense fog will persist until mid morning.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be 
sure to leave plenty of distance between your vehicle and the one 
ahead of you.

&&

$$

Iovino
797 
WWUS71 KPHI 231317
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
817 AM EST Thu Feb 23 2017

NJZ016>025-027-231430-
/O.CAN.KPHI.FG.Y.0003.000000T0000Z-170223T1500Z/
Salem-Gloucester-Camden-Northwestern Burlington-Ocean-Cumberland-
Atlantic-Cape May-Atlantic Coastal Cape May-Coastal Atlantic-
Southeastern Burlington-
Including the cities of Pennsville, Glassboro, Camden, 
Cherry Hill, Moorestown, Mount Holly, Jackson, Millville, 
Hammonton, Cape May Court House, Ocean City, Atlantic City, 
and Wharton State Forest
817 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IS CANCELLED...

The National Weather Service in Mount Holly has cancelled the
Dense Fog Advisory.

The dense fog has lifted across southern New Jersey this morning.
Visibilities will continue to improve across the region later into
the morning.

$$

PAZ054-061-062-231600-
/O.EXB.KPHI.FG.Y.0003.000000T0000Z-170223T1600Z/
Carbon-Lehigh-Northampton-
Including the cities of Jim Thorpe, Allentown, Bethlehem, 
and Easton
817 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM EST THIS MORNING...

The National Weather Service in Mount Holly has issued a Dense
Fog Advisory...which is in effect until 11 AM EST this morning.

* LOCATIONS...Carbon, Lehigh and Northampton counties in eastern 
  Pennsylvania.

* VISIBILITY...One-quarter mile or less in spots.

* TIMING...The areas of dense fog will continue to expand
  northward into the Lehigh Valley through 9 AM before dissipating
  late this morning.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be
sure to leave plenty of distance between your vehicle and the one
ahead of you.

&&

$$

DEZ001-MDZ008-012-NJZ009-010-012>015-026-PAZ060-070-071-101>106-
231600-
/O.EXT.KPHI.FG.Y.0003.000000T0000Z-170223T1600Z/
New Castle-Cecil-Kent MD-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Coastal Ocean-Berks-
Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Chestertown, 
Flemington, Somerville, New Brunswick, Freehold, Sandy Hook, 
Trenton, Long Beach Island, Reading, Media, Philadelphia, 
Honey Brook, Oxford, West Chester, Kennett Square, Collegeville, 
Pottstown, Norristown, Lansdale, Chalfont, Perkasie, Morrisville,
and Doylestown
817 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY NOW IN EFFECT UNTIL 11 AM EST THIS
MORNING...

* LOCATIONS...Northeastern Maryland, northern Delaware,
  southeastern Pennsylvania and central New Jersey.

* VISIBILITY...One-quarter mile or less in spots.

* TIMING...Areas of dense fog this morning will gradually
  dissipate from southeast to northwest across the region between
  9 AM and 11 AM.

* IMPACTS...The dense fog and reduced visibility will create 
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means that the visibility will be reduced to
less than one quarter mile. If driving, use extra caution and be
sure to leave plenty of distance between your vehicle and the one
ahead of you.

&&

$$
JRK
013 
WWUS71 KPHI 231458
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
958 AM EST Thu Feb 23 2017

DEZ001-MDZ008-012-NJZ009-010-012>015-026-PAZ054-060>062-070-071-
101>106-231600-
/O.CAN.KPHI.FG.Y.0003.000000T0000Z-170223T1600Z/
New Castle-Cecil-Kent MD-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Coastal Ocean-Carbon-
Berks-Lehigh-Northampton-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Elkton, Chestertown, 
Flemington, Somerville, New Brunswick, Freehold, Sandy Hook, 
Trenton, Long Beach Island, Jim Thorpe, Reading, Allentown, 
Bethlehem, Easton, Media, Philadelphia, Honey Brook, Oxford, 
West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
958 AM EST Thu Feb 23 2017

...DENSE FOG ADVISORY IS CANCELLED...

The National Weather Service in Mount Holly has cancelled the
Dense Fog Advisory.

The dense fog has lifted with visibilities continuing to improve 
across the region late this morning.

$$
JRK

What forecasters said that day

The local office's own words before this dense fog advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before this dense fog advisory went out at Feb 22, 9:14 PM EST, 5 hours 44 minutes earlier.

Area forecast discussion, Feb 22, 9:14 PM EST, 5 hours 44 minutes before
Area Forecast Discussion
National Weather Service Mount Holly NJ
914 PM EST Wed Feb 22 2017

.SYNOPSIS...
High pressure will remain centered east of the Mid Atlantic coast
through the end of the week. A cold front will approach from the
west Thursday then stall at night, before lifting northward as a
warm front Friday. A strengthening low pressure system will develop
over the Plains and track across the Great Lakes Saturday, with a
strong cold front sweeping across our area Saturday afternoon. High
pressure then builds to our south later Sunday into Monday. The next
cold front arrives during Monday before stalling to our south, then
it should move northward as a warm front Wednesday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
930 PM ESTF: Will adjust temp/dews fcst.

SPS may be issued overnight for much of the area for patchy
dense fog by dawn.

Stratus at 300 feet has started developing near CGE. That should
reach PHL around 08z then up to our far northern areas around
10-11z/23.

Expect favorable radiational cooling conditions this evening under
variable clearing cirrus with a light south wind. Models indicate
stratus forming to our south toward the mouth of the Chesapeake
Bay and lower Delmarva this evening, then advecting/expanding
to the north- northeast overnight across the coastal plain.
Farther north into eastern PA and NJ, a better setup for radiational
fog looks to exist since the stratus should arrive later in the
night or possibly not until early morning. While locally dense
fog is a possibility toward daybreak, the current thinking is
the stratus will limit the extent of it. Differences between
models in timing and areal coverage of the fog/stratus contribute
to some uncertainty with this aspect of the forecast.

Most of the region should remain dry tonight but a weak disturbance
tracking over Delmarva may be accompanied by an isolated shower
or patchy drizzle overnight.

Forecast low temperatures range from the upper 30s in the sheltered
valleys in northwestern NJ to the upper 40s in the the cities and
mid Delmarva region.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
High pressure will remain anchored off the Mid-Atlantic coast on
Thursday. Return flow around the high will allow the spring-like
warmth with build into tomorrow. Near-record high temperatures are
forecast from about the Philadelphia region southward. It is
important to note some uncertainty with the temperatures exists with
the forecast for tomorrow. How warm we will get will depend on how
quickly the morning fog and stratus mixes out. Stratus occasionally
is stubborn to erode this time of year due to the low sun angle.
Where stratus persists into the afternoon, highs will be in the 60s
vs the 70s. Forecast soundings and RH fields show lower clouds
eroding from south to north during the late morning and afternoon.
Accordingly, highs in the low to mid 70s are favored in Delmarva,
southeastern PA and southern NJ with 60s farther north.

A weakening cold front will approach from the west during the
afternoon. Models generally show enough lift to support isolated
to scattered convection in our far western zones of eastern PA
and northwestern NJ during the mid to late afternoon. Forecast
soundings show a weak mid-level cap in place. Added a slight
chance for thunderstorms out toward Reading and in the southern
Poconos, where a relative min in CIN indicates a low potential
for deeper convective to develop.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Summary...Potential for near record warmth through late week,
followed by a strong cold front Saturday afternoon and evening.

The synoptic setup is comprised of a digging trough across the
Plains and Midwest Thursday night and Friday, then this moves across
the Great Lakes Friday night and Saturday before lifting across
the Northeast and eastern Canada. The flow may then turn more
zonal for awhile allowing for some moderation in the temperatures
once again after a brief shot of cooler air. We used a model
blend for Thursday night through Friday night, then blended in
the 12z WPC Guidance thereafter. Some adjustments were then made
following additional collaboration with our neighboring offices.

For Thursday night and Friday...A frontal boundary near our northern
zones Thursday night into Friday morning should shift northward as a
warm front. This is due to increasing flow and warm air advection
ahead of a organizing/strengthening storm in the Northern Plains.
There is not a lot of focused lift, however some showers could
result. Some fog and low clouds should develop each night as the low-
level moisture increases. Despite Friday starting out with more
clouds and some fog, enough clearing should take place to allow for
ample boundary layer warming and there is the potential for record
highs. It appears that any showers with the warm front Friday should
be shifting north of our area. Some thunder may occur near the
northward moving front especially to our west, however this may tend
to weaken with an eastward extent.

For Saturday and Sunday...A strong upper-level trough will move
across the Great Lakes and Northeast Saturday and Saturday night,
sweeping a strong cold front across our area. Some low clouds
and fog may be around to start Saturday. We should be within
the warm sector and the synoptic pattern is favorable for at
least some convection to move through the area ahead of or with
the cold front. Forecast soundings show a strengthening wind
field ahead of the cold front Saturday with some instability
(high shear-low CAPE scenario). While the instability may be on
the low side, frontal/synoptic forcing and moisture advection
could result in a low-topped convective line. As a result, a
mention of thunder is maintained in the forecast ahead of the
cold front however the strength of the convection is less
certain at this time. While it will be another warm day on
Saturday, it appears that high temperatures fall short of
records. Once the cold front sweeps through later Saturday, cold
air advection and much drier air moves in for Saturday night
and Sunday. Given the front offshore Sunday, dry and much cooler
on Sunday along with a gusty northwesterly wind.

For Monday through Wednesday...High pressure shifts off the
Southeast coast to start Monday, with a cold front moving
through our area. This looks to be on the weaker side however
cannot rule out a few rain/snow showers. As another storm system
ramps up across the Plains, the front should stall just to our
south into Tuesday before starting to move northward as a warm
front Wednesday. Low pressure looks to track once again across
the Great Lakes with a driving warm sector northbound Wednesday.
We went with a chance of showers (rain/snow showers Monday
night) Tuesday ahead of the warm front then with some higher
PoPs on Wednesday as the cold front nears.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR with some cirrus and light south wind. IFR st/fog
forms between now and 05z much of the Delmarva into far southern
NJ and then into PHL between 06z-07z ABE and TTN near 09z. Widespread
IFR conds by 10z except possibly parts of s NJ near KMIV where
it could be MVFR CIGS/VSBY. Patches of embedded LIFR st/fog
expected, especially KILG/KPHL/KPNE/KABE/KTTN toward 10z.

Confidence in quite high that cigs between 500 and 1500 feet will
form most TAF sites between 06z and 10z. But timing of the vsby
below 1 mile is below normal.

Thursday...IFR/LIFR conds in st/fog most TAF sites and maybe
even a little mist will all be slow to erode/lift from south to
north but should reach MVFR or VFR vsby by 17z with cigs at that
time between 1500-3500 and rising/thinning. Please see TAFS for
details. Light south to southwest winds in the morning increase
to around 10 kt with gusts 15-20 kt during mid afternoon.

OUTLOOK...
Thursday night and Friday...VFR ceilings may lower to MVFR/IFR
Thursday night into Friday morning along with MVFR/IFR visibility
due to fog. Conditions should improve during Friday, however some
low clouds and fog may then redevelop Friday night. Some showers are
possible mainly Thursday night and Friday morning with a warm front
lifting northward.

Saturday...There is the potential for MVFR/IFR conditions at times
with showers and potential thunderstorms with a cold front.
Conditions should improve at night in the wake of the cold front.
Southerly winds ahead of the cold front potentially gusty, turn west
and northwest at night.

Sunday and Monday...VFR overall. West-northwest wind gusts up to 30
knots possible Sunday, then diminishing at night and Monday.

&&

.MARINE...
An MWS for FOG or even MWW DENSE FOG Advisory for dense fog may
be needed for late tonight and Thursday morning.

Winds and seas below SCA levels tonight and Thursday. Expect
fog to develop tonight and may be locally dense in spots late
tonight and Thursday morning as dewpoints rise into the
mid/upper 40s and maybe near 50F south.

OUTLOOK...
A frontal zone Thursday night will lift north as a warm front
through Friday, which should become located to our north during
Friday. An increase in warmth and dew points may result in some
dense fog developing on the waters especially Friday through early
Saturday. A strong cold front arrives later Saturday, with gusty
southerly winds becoming west-northwest in its wake. Small Craft
Advisory conditions may develop mainly Saturday and Sunday. Much
warmer air over cooler waters though should limit the mixing
Saturday, then improved mixing Saturday night and Sunday as cooler
air arrives. There is a chance for a period of low-end gale force
gusts Sunday. The conditions should then be below Small Craft
Advisory criteria Monday.

&&

.CLIMATE...
For those who refer to the RTPPHI: it hasn't run correctly on
its 715 AM/PM cron since the 20th but we were able to produce
a version around 8 PM tonight. Not all the trace amounts of rain
are in there. This will have to suffice until an improved fix
hopefully is implemented Thursday evening. Thank you.

For reference, here are the high temperature records for Thursday,
Friday and Saturday.

Location    Thursday 2/23   Friday 2/24   Saturday 2/25

ACY         72-1985         75-1985       77-1930

PHL         75-1874         74-1985       79-1930

ILG         72-1985         78-1985       78-1930

ABE         71-1985         76-1985       74-1930

TTN         74-1874         74-1985       76-1930

GED         67-1985/1990    72-1961       76-1975

RDG         72/1932/1922    77-1985       77-1930

MPO         60-1977         60-1984       70-1930

The following monthly and seasonal expectations were recalculated
with todays max/min and then the official 330 PM Mount Holly
forecast.

There is some uncertainty about max temps reaching our predicted
values Thursday...they could run 4 to 6 degrees cooler than our
forecast since low clouds and fog may be slow to clear...just
like todays mid deck was slow to clear and scored very well for
the superblend/national blend and WPC forecasts from the 12z
cycles of 18th- 19th-20th...as best forecasts..for the max
temps of today...Wednesday the 22nd. The big cool bias of NCEP
MOS from late last week and last weekend is for now almost non
existent for the past two days (21st- 22nd).

It is virtually certain that the numbers below will stand and
that our forecast area is experiencing a record warm, or at
least a 2nd warmest January on record and a top 10 warmest
winter.

Records date back to the late 19th century. Details below. These
values are probably on the lower side of the solutions.

February:

PHL 43.3. #1   Normal 35.7   Record 42.2-1925     POR 1874

ABE 37.6  #2   Normal 30.7   Record 38.6-1998     POR 1922
There is a pretty good chance ABE will end up warmer, very very
close to the record.

ACY 42.2  #1   Normal 35.3   Record 41.6-1890     POR 1874

ILG 42.3  #1 tie  Normal 35.1 Record 42.3-1903    POR 1895

Winter (DJF)

PHL 40.1 #7

ABE 35.4 #5

ACY 39.6 #10

ILG 39.1 #6 tie

Past two years of monthly average temperatures through February
2017, a summary of above normal months listed below:

For ABE: 23 consecutive months of above normal temps!

FOR PHL: 22 of the past 23 months have been above normal.

For ACY: 19 of the past 23 months have been above normal. For ILG:
17 of the past 23 months have been above normal.

(Jan Feb March 2015 was the last time we had significant and
persistent below normal monthly temps.)

Snow:

February least on record:

Atlantic City should/could end up tied for 5th.

&&

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

&&

Synopsis...Gorse
Near Term...Drag/Klein 914
Short Term...Klein
Long Term...Franck/Gorse
Aviation...Drag/Gorse/Klein 914
Marine...Drag/Gorse/Klein 914
Climate...914
Hazardous weather outlook, Feb 22, 3:45 PM EST, 11 hours 13 minutes before
Hazardous Weather Outlook
National Weather Service Mount Holly NJ
345 PM EST Wed Feb 22 2017

DEZ001>004-MDZ008-012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-070-071-101>106-232045-
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Sussex-Warren-Morris-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-Carbon-Monroe-Berks-Lehigh-Northampton-
Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
345 PM EST Wed Feb 22 2017

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...northeast Pennsylvania and
southeast Pennsylvania.

.DAY ONE...This Afternoon and Tonight.

Locally dense fog may develop late tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Locally dense fog may occur Thursday morning and again Friday
morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

ANZ430-431-450>455-232045-
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 PM EST Wed Feb 22 2017

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

.DAY ONE...This Afternoon and Tonight.

Locally dense fog may develop late tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Locally dense fog may occur Thursday morning, Thursday night and
Friday morning, and Friday night.

A period of northwesterly gale force gusts to 35 knots are possible
Sunday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 23, 3:00 AM ESTMarine Dense Fog AdvisoryPHI9 hr

Nearby

Dense Fog Advisories in New Jersey, 2017Dense Fog Advisories in Pennsylvania, 2017Dense Fog Advisories in Maryland, 2017Every dense fog advisory in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.