Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
FXUS61 KPHI 011548
Area Forecast Discussion
National Weather Service Mount Holly NJ
1148 AM EDT Sat Oct 1 2016
Persistent low pressure to that has been sitting to our west the
last few days will finally start to lift northeast as it weakens. By
Monday, the low will be over New England, and the associated cold
front will slide through our region. A surface high will build and
stay north our our region through much of the remainder of the work
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A moist low-level flow continues with high pressure in eastern
Canada and a closed low well to our west. A frontal boundary to
our south is trying to work northward in response to a short wave
that is just off the Delmarva coast. Radar data shows an area of
showers north of this feature, which also extends northwestward
into southern Pennsylvania. There has been some lightning with the
convection near the lower Delmarva coast, however it appears to
becoming more stratiform as it shifts northward. Otherwise, some
drizzle continues given the moist low-level onshore flow and a
pronounced inversion. Some fog remains, mainly in the higher
terrain of the Poconos.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
The low to our west will begin lifting into the Great Lakes
overnight. While doing so, the associated occluded front to our
south is expected to begin lifting toward the area late in the
night and into Sunday morning. There could be some showers to
begin the evening as a vorticity impulse slides north of the area.
Another vorticity impulse may approach the area overnight, leading
to more scattered showers, but areas of fog and drizzle will
likely continue through the night. Visibilities could get quite
low tonight, so we will need to monitor in case we need a Dense
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Sunday and Monday...The low pressure system that has been
stubbornly sitting to our west the last several days should first
lift NE on Sunday, with continued on shore flow, there could be
some light rain during the day, but in general the period will be
mostly dry. By Monday, the low may dig southeast, sliding off
shore. In its wake, an upper level short wave ridge builds in.
Tuesday through Thursday...through this period, a surface high
will remain north of our region, with the upper level ridge slowly
sliding east through the period. Low level on shore flow is
expected, but expect little precip through the period as
subsidence associated with the ridge should continue through the
period. More likely, we will just see persistent cloud cover for
much of the period.
Friday through Saturday...forecast through this period is very
uncertain thanks to uncertainty with the evolution of Hurricane
Matthew. For now have stayed close to the previous forecast and an
average of guidance through this period. However we will
continue to monitor the forecast track over the next several days.
Please see latest NHC advisories for the latest information on
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
IFR/LIFR ceilings due to low clouds and some drizzle for the rest
of today and tonight. Some showers may arrive from the south this
afternoon. While the visibility through this afternoon are mainly
VFR, some lowering is expected at times due to drizzle and or a
shower. Northeasterly winds mostly around 10 knots.
For tonight, visibilities late into Sunday morning could get
quite low in some areas due to fog (one mile or less). Northeast
to east winds diminish overnight to 5 knots or less.
Sunday through Tuesday...mostly VFR conditions expected. Small
chance of showers with MVFR conditions Sunday and Tuesday.
Wednesday...conditions lowering to IFR for Delaware Valley Sites
(KPHL, KILG, KTTN, KPNE) and Coastal Plains (KMIV and KACY) as
onshore flow results in low stratus clouds.
The Small Craft Advisory for the lower Delaware Bay was extended
until 4 PM as some gusts to 25 knots are still occurring.
The winds will diminish by later this afternoon into tonight,
however seas on the ocean will remain at or above 5 feet through
about the first half of tonight.
Sunday and Monday...winds and seas should stay below SCA criteria.
Tuesday and Wednesday...Winds and seas are expected to build
through the day Tuesday, and SCA conditions could develop as early
as mid day Tuesday.
The Coastal Flood Advisory was cancelled as the departures lowered
substantially going into the high tide. As of now, levels should
be below advisory threshold for the next high tide cycle.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ450>455.
Small Craft Advisory until 4 PM EDT this afternoon for ANZ431.