Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 231843
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
143 PM EST Thu Feb 23 2017

.SYNOPSIS...
A cold front moving through the Great Lakes today will stall
just north of our region tonight into Friday, before lifting
northward as a warm front Friday night. This will be followed by
a strong cold frontal passage on Saturday evening. High
pressure will traverse the middle Atlantic Sunday into Monday. A
frontal boundary will setup near our region during the early to
middle part of next week, and several waves of low pressure are
expected move along it.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Residual stratus deck from this morning had mixed out a bit
earlier than previously anticipated. A cold front was analyzed
well to our west across the eastern Great Lakes and Midwest
region early this afternoon. The leading edge of the CU field in
the pre-frontal warm sector was moving into our far western
zones of eastern PA. Otherwise, plenty of sunshine during peak
heating will allow for temperatures to reach their full
potential as we mix down the warm air aloft. Temperatures were
adjusted upward across the entire area, most notably across
eastern PA and central NJ, where we previously had kept them
lower in anticipation of a cloudier start to the afternoon. High
temperatures with the early afternoon update range from the
mid/upper 60s north and west of the Fall Line to the lower 70s
along the I-95 corridor and mid 70s farther southeast in the
coastal plain of southern NJ and Delmarva. However, it will be
considerably cooler (upper 50s-mid 60s) at the beaches due to
the influence of the colder ocean waters.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
Our region should be more solidly in the warm air for tonight.
As a result, we may see more stratus than fog development except
near the water. Nevertheless, we will continue to mention at
least some patchy fog for late tonight.

Scattered showers may spread across parts of eastern
Pennsylvania and northern and central New Jersey. Rainfall
amounts should be light, generally a few hundredths of an inch.

The wind is forecast to be light for tonight and low
temperatures should range from the middle 40s in the Poconos and
far northern New Jersey to the lower 50s on the coastal plain.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Active pattern in the Friday thru Wednesday period. Dense fog
is possible Friday and Friday night. There is a marginal risk of
severe thunderstorms on Saturday. There is also the potential
for daily record high temperatures on Friday, especially
Delmarva. Temperatures cool to seasonal levels on Sunday.

A more zonal flow sets up in the Monday thru Wednesday time
frame with additional chances of light precip along with a
return to above average temperatures. There is a lot of
uncertainty regarding coverage and timing of precip in the early
to middle part of next week.

Friday will feature a warm front just north of the area, with
diffuse shortwave energy moving along it. This will promote the
chance for scattered rain showers, mainly north of an I-195 to
PA Turnpike line. Given the proximity of a warm front, which may
briefly backdoor to the south, we anticipate considerable
cloudiness across much of NJ and eastern PA. This is reflected
in our temperature grids, and will likely limit record high
potential across this area. Further south across Delmarva, we
have maintained warmer temperatures (mid-70s), and thus there is
a greater potential of setting records across this area. With
the nearby frontal boundary, we expect fog through mid- morning
Friday and again Friday night. The fog could be dense, and we
have continued a mention of this in the HWO.

Saturday and Sunday...A strong cold front moves through the
region Saturday evening. The synoptic pattern is favorable for a
squall/convective line to move through much of the area, and
SPC has placed our entire region within a marginal risk of
severe thunderstorms in their day 3 convective outlook. Thus, we
maintain a chance of thunder in the forecast. Some heavier
downpours are also likely, but amounts are expected to be less
than one inch. High temperatures on Saturday are expected to
fall just shy of daily records. Fair weather is expected for
Sunday, with a return to near normal temperatures, and gusty
west-northwest winds.

Looking ahead to Monday thru Wednesday, several shortwaves will
interact with a frontal boundary that sets up near our region,
offering additional chances of light precipitation. Details in
timing and coverage continues to be low, so the forecast shows a
general slight chance of showers during this period. Snow
showers are possible Monday and Tuesday nights. We expect
temperatures to return to above average levels, generally around
5 to 10 degrees above normal.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

VFR conditions thru the remainder of the afternoon and into
this evening for most locations. However, convective showers and
perhaps an isolated thunderstorm may organize ahead of a cold
front this afternoon, possibly reaching RDG-ABE during the late
evening or overnight (02Z-07Z). Then a return of low clouds and
fog is expected late tonight.

A light southwest and south around 5 kt this morning will
increase to 10 kt this afternoon. Gusts at or slightly above 15
kt are likely for the southern (PHL south) mid to late afternoon.
The wind is anticipated to become light and variable again for
tonight.

OUTLOOK..

Friday through Saturday...There is the potential for MVFR/IFR
at times, especially Friday night, and again on Saturday with
showers and potential thunderstorms ahead of a cold front. Winds
out of the south on Saturday could gust up to around 20 knots.

Saturday night and Sunday...Becoming VFR Saturday night with
gusty west-northwest winds anticipated into Sunday, 25 to 30
knots at times.

&&

.MARINE...
No marine hazards expected this afternoon and evening. A light
S-SW wind 5-10 kt early this afternoon will increase to 10-15 kt
late in the day and this evening over the Atlantic coastal
waters.

Another round of dense fog may occur over the waters as early
as overnight tonight or early Friday morning. We will consider
issuing a marine dense fog advisory later this afternoon or this
evening.

OUTLOOK...

Dense fog on Friday could potential persist into Saturday across
a portion of the waters as anomalously moist air (characterized
by dewpoints in the 50s) ahead of a cold front moves atop the
colder waters (SSTs still in the low to mid 40s).

Sub-SCA conditions are forecast Friday. SCA possible Friday
night thru Monday, with period of gales possible on Sunday. Sub-
SCA conditions are forecast Tuesday.

&&

.CLIMATE...
As of 140 PM...two daily record highs were set as of 130 PM
this afternoon:  74F at Georgetown and 61F at Mount Pocono.
Atlantic City is currently 71F, which is one degree shy of tying
its daily climate record. RERs are currently being sent.

For reference, here are the high temperature records for today,
Friday and Saturday (not including the records broken so far
today).

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.

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 February 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
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

Note for ABE: There is a pretty good chance ABE will end up
warmer and possibly very close to their monthly temp record.


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:

Atlantic City should/could end up tied for 5th least snowiest
February on record.

&&

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

&&

$$
Synopsis...Franck
Near Term...Klein
Short Term...Iovino
Long Term...Franck
Aviation...Franck/Iovino/Klein
Marine...Franck/Iovino/Klein
Climate...Drag/Klein



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