Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
FXUS61 KPHI 230019
Area Forecast Discussion
National Weather Service Mount Holly NJ
819 PM EDT Thu Sep 22 2016
A cold front will move across the area later on Friday into Friday
night. High pressure will build across the northeast over the
weekend into early next week. A warm front is expected to lift north
of the area around Tuesday, while a cold front remains to our
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
High pressure off the coast will move away from the area tonight.
This will keep quiet and dry weather conditions over the region.
Temps will be at or slightly above normal values.
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A wk front will pass to the n late Friday as large high pressure
builds down from Canada. This front may trigger some showers or
even a thunderstorm mainly over nrn areas late Fri aftn. There is
some disagreement in the guid wrt this feature. THe NAM/WRF brings
the precip further s, even to the 1-95 corridor. The ECMWF, on the
other hand, is virtually dry. For now, the GFS seems like a good
compromise, keeping the precip over the n. Temps will be more
summer-like in the mid to upper 80s.
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
The cold front will fully push south of the area Friday night.
There will be a slight chance of showers, mainly across the
northern third of the area, as a short wave/vorticity impulse
slides across the area and interacts with the front. High pressure
will then build across the northeast over the weekend and into
Monday of next week. This will bring cooler weather to the area,
along with dry conditions.
There are differences between the GFS and ECMWF as we move into
Tuesday, as the GFS lifts a warm front through the area, while the
ECMWF moves a cold front across the area. We decided to stay
closer to WPC and continuity. This would keep the cold front to
our west through the end of the week, before it possibly reaches
the area Thursday into Friday. There will remain a slight chance
of showers each day from Tuesday through the end of the week,
although it will only be 20 percent at this time.
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
VFR conditions are expected tonight and tomorrow. There remains a
small chance for fog, primarily at the more rural TAF sites, but
have removed any mention from the TAFs as dew points are running
lower than they were at this time last night, and there was
limited fog development last night. Winds are expected to be
light and variable through at least 12Z, before settling in out of
the west by 15Z. Even after 15Z, wind speeds should be less than
Friday night-Tuesday...VFR conditions expected.
Have canceled the small craft advisory as all available
observations are well below 5 feet, and seas are forecast to
decrease slightly through the evening hours. Wind gusts near 20 kt
are possible through the overnight hours, and seas should stay in
the 2 to 4 foot range tonight and tomorrow. However, winds and
seas are expected to remain below SCA criteria.
Friday night-Saturday...Conditions may approach Small Craft
Advisory levels. Winds may gust around 20 to 25 knots at times
behind a cold frontal passage Friday night into Saturday morning.
Seas could approach 4-5 feet during the day Saturday as well.
Saturday night-Tuesday...Sub-Small Craft Advisory conditions
expected through. Winds may gust around 20 knots at times.
The probable risk for the formation of dangerous rip currents on
Friday is low, but it may be on the cusp of moderate depending on
how quickly winds will shift out of the west.
Weekend...There is a chance of a moderate risk for the formation of
dangerous rip currents on at least one of the weekend days, as a 3
to 4 foot east-southeast swell from Tropical Cyclone Karl arrives
along with a gusty northeast wind. Karl`s lack of development may
result in a lower swell which would help reduce the potential
risk for the formation of dangerous rip currents.