Area Forecast Discussion
Issued by NWS Mt. Holly, NJ-- Remove Highlighting --
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FXUS61 KPHI 290811
Area Forecast Discussion
National Weather Service Mount Holly NJ
411 AM EDT Wed Mar 29 2017
High pressure near Hudson`s Bay will build into our region
through Wednesday night. Low pressure moving through the Ohio
Valley on Friday will redevelop near the New Jersey coast
Friday night and move offshore on Saturday. High pressure
will move into the area for Sunday and Monday. Low pressure
over the Ohio Valley and its associated fronts will approach
our region on Tuesday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Early this morning...slow clearing. north to northwest wind 5-15
Today...Partly to mostly sunny with a gusty north to northwest
wind 10-25 mph. Max t in PHL today around 62-63F. Slightly above
normal max temps.
Forecast basis: 50 50 blended 00z/29 GFS/NAM MOS guidance and
the EC 2m temps which has 58 in PHL at 2 PM. I usually add 4-5F
on a p-m/s day with decently mixing n-w wind.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
Clear or mostly clear skies, a few fragments of sc in the early
eve and possibly a little cirrus. Some radiational cooling
expected. Light north wind. Normal or slightly below normal
Forecast basis: 50 50 blended 00z/29 GFS/NAM MOS guidance.
Applied minor 1-2F cooler than guidance adjustments in our 330
AM fcst for tonight.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The primary players during the long term will be two southern
stream systems that are expected to impact our region in the
Friday-Saturday and Tuesday time frames.
The first system may produce 1 to 1.5 inches of rain across
portions of the region, especially in the Delaware Valley. While
there could be some urban and poor drainage flooding, we do not
expect any major impacts on rivers and streams. There is also a
consistent signal in the models for mixed precip north of I-80,
with sleet and freezing rain the primary concerns, during the
Friday night and Saturday morning period. We have mentioned this
in the HWO.
Looking ahead to early next week, the next system is expected to
bring more precip to our region Monday night into Tuesday. This
setup looks warmer, given the absence of high latitude blocking,
and would favor predominantly rain.
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Through 12z...Still some leftover IFR/MVFR conds which will be
improving to VFR sct clouds by 12z. North to northwest wind 5 to
After 12z...VFR sct-bkn near 4000 ft will become VFR clr by
21z. North to northwest wind gusty 20-25 kt.
Tonight...VFR with fragments of sc in the evening and maybe some
thin cirrus at times. Light north wind.
Predominantly VFR, except MVFR possible Friday into Saturday.
No headlines through tonight. Northerly flow becomes northwest
during the daylight hours with gusts 20 kt. A few gusts 25 kt
possible this evening in the NNJ waters when we may need to
issue a short fuse SCA, then northerly winds diminishing early
SCA likely Friday into Saturday, with the potential for gale
force southeasterly wind gusts Friday night, mainly across the
northern NJ waters. Otherwise, sub-SCA.
Though astronomical tides will be gradually diminishing through the
week now that we are past the new moon, the threat of minor tidal
flooding along the NJ and DE Atlantic coasts increases late in the
week. This is a result of a low pressure system bringing a prolonged
period of onshore flow. The tide of most concern at this point
is the high tide on Friday evening/late Friday night. By this
tide cycle, it will take a surge of 0.8 to 1.0 feet to reach
minor flooding thresholds, which is possible but still uncertain
(it will be dependent on how quickly the on shore flow develops
and how strong it will be by then). At least one source of
guidance shows water levels reaching minor tidal flooding
thresholds with the Thursday evening/night high tide, but that
seems unlikely as the latest forecast depicts onshore flow
either developing right around or just after the time of that
We have mentioned the potential of minor flooding along the
northern NJ coast in the HWO, where the threat is greatest
during the Friday evening/late Friday night high tide cycle.
-- Changed Discussion --Mo avg temps
March Dep Feb DEP
ABE 38.0 -1.1 39.2 +8.5
ACY 41.6 -0.6 43.0 +7.7
ILG 41.7 -1.3 43.1 +8.0
PHL 42.2 -1.3 44.2 +8.5
First of all: This March will be a below normal month for
temps.... One of the VERY few the last two years.
Second, we appreciate that this is possibly old news, but March
temperatures will average colder than the FEB average at all 4
long term climate locations. The last time this occurred, 1984.
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