Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
933 am EST Sat Mar 8 2014
weak high pressure will build into the region today. A cold front
will then cross the area tonight into Sunday morning. A large area
of high pressure will then build in behind the front for the first
part of next week. A weak cold front will cross the area Monday
night as the high moves southward. Then, an area of low pressure,
developing over the Gulf of Mexico, will move northeastward and
will begin to impact the region Wednesday into early Thursday.
High pressure will build back in behind the departing low.
Near term /until 6 PM this evening/...
the biggest change with this short term update is to boost maximum
temperatures about 3-6f. Latest 12z soundings full sun potential showing
50s to middle 60s in our County Warning Area. This does not take into consideration
the leftover snow cover and some cloudiness arriving today. Thus
we shaved some off for that and also they were too energetic with
maximum temperature suggestions this week. The rest of the forecast kept
pretty much as is.
A rather pleasant early March day is in store across the region.
Ample sunshine is expected for the forecast area, especially through
the first half of the day, before a cold front begins to approach
the region from the northwest during the middle to late afternoon.
Clouds will be on the increase ahead of this boundary during the
afternoon hours, from northwest to southeast. There looks to be
limited moisture associated with this boundary as it approaches our
northwest zones late in the day, but we have kept slight chance probability of precipitation
for light rain/snow showers mainly across the southern Poconos for
the late afternoon to early evening.
Winds are expected to remain on the lighter side for most of the
region, generally out of the northwest early and becoming west-
northwest into the afternoon.
Short term /6 PM this evening through 6 am Sunday/...
going through the evening to overnight, the previously mentioned
cold front will gradually traverse the area from northwest to
southeast, clearing our region before daybreak Sunday. While
moisture overall continues to be limited with this boundary as it
passes over the region, model guidance has been consistent in
squeezing out a few rain/snow showers as it sags southeast through
the area. As the precipitation will be light and areal coverage scattered
at best, we carry mostly slight chance probability of precipitation. Less than a tenth of an
inch quantitative precipitation forecast is expected, with most areas seeing a few hundredths of an
inch at best. Some forecast sounding data indicates the possibility for
freezing drizzle, and this is included for our northwest areas into
the southern Poconos, Lehigh Valley region, and northwest New Jersey.
Overnight temperatures were mostly a met/mav blend with continuity,
and we expect minimum temperatures to range from the Lower/Middle 20s far
north to the middle 30s in the Delaware-Maryland-Virginia.
Also...daylight saving time begins Sunday morning at 2 am, so
please remember to turn your clocks ahead one hour (spring ahead)
before going to bed.
Long term /Sunday through Friday/...
the extendd period is fairly quiet, with temperatures generally near or above normal
(something that I haven't been able to say for quite some time!),
With the exception of the Wednesday-Thursday time frame.
On sun, high pressure will be build in from the W, behind the passage
of a cold front. Sun looks to be dry. Monday should be dry as well, but a
weak cold front/clipper type system will approach from the northwest. A few snow or
rain showers can not be ruled out north and west with the weak front.
By Tue, west to SW flow aloft picks up in advance of a developing low
in the Gulf of Mexico. Tuesday looks to be the warmest day of the period. This low
then moves northeastward Tuesday nigh and begins to impact the region late Tuesday
night or Wednesday morning.
All of the guidance has weakened the low with th 08/00z cycle.
However, it still remains strongest in the European model (ecmwf). The European model (ecmwf)
remains the slowest of the guidance (that is about as surprising as
the sun rising in the east!). the greatest impacts, based on
current timing look to be during the day Wednesday. The GFS is fastest,
basically ending all precipitation by Wednesday evening. The CMC has precipitation over by
Thursday morning. The European model (ecmwf) is winding things down during Thursday am, but is
probably not done until Thursday late morning or afternoon. The European model (ecmwf) is quite
a bit stronger with the low after it passes US (as it has been all
along) than the other models as well. So there is still quite a bit
of uncertainty with respect to timing and ultimately the track of the low.
For now, will go with a blend, will remove probability of precipitation from Tuesday night
then ramp things up on Wednesday and then down during Thursday. Also, attm,
this looks to be predominantly a rain event on Wed, but will
likely mix and change to snow before ending from northwest to southeast Wednesday
night into Thursday. As usual, it will be the question of how much
moisture will be left by the time the colder air moves in. The
models still have about 5 days to work these details out and will
continue to just hold onto some form of rain and snow in the
grids. High pressure will then build in behind the departing low
for Thursday night into Friday.
High temperatures should steadily rise through Tue, before decreasing but
should generally be in the 40s and 50s for most locations through the
extendd period. The colder northern and western areas will likely only see 30s
on Thursday and Friday. Overnight lows will mainly be in the 20s and 30s.
With some teens north and west.
Aviation /15z Saturday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
Today...overall, mainly VFR conditions. Mainly light and variable
winds are expected at krdg/kabe through early today. Elsewhere, a
northwest wind at 10kt or less will prevail early, becoming more
west- northwest with some possible gusts in the 15 to 18kt range
for this afternoon from around kphl south and east.
Tonight...mainly VFR conditions are expected to continue. A cold
front will be moving through the area from northwest to southeast
during the late evening to overnight. While limited moisture is
associated with this boundary, we cannot rule out a few light
rain/snow showers along and behind the frontal boundary. This could
lead to some brief periods of sub-VFR conditions, but confidence on
timing and location is below average at this time. Winds are
expected to be west-northwest at 10 knots or less during the evening,
becoming more northwest following the frontal passage.
sun...mainly VFR. There could be some lingering low clouds early
and possible lower cigs, but these should dissipate as high pressure builds
in. MDT to high confidence.
Mon-Tue...VFR. High pressure. High confidence.
Tuesday night-Wed...MVFR or lower in scattered showers. Increasing chances
for more rain/snow during Wednesday as low pressure approaches from the
SW. Low to MDT confidence on timing. Higher confidence on impacts
when they occur.
in the wake of a coastal low pressure to our southeast that is now
quickly moving out to sea, elevated seas will continue for our
coastal waters. We have extended our current Small Craft Advisory
for all of our coastal waters later into the night based on seas
running about a foot higher than latest wave watch guidance. At
this time, seas in the 5 to 8 foot range will continue for our
coastal waters, highest for our southern waters. A gradual
downward trend for seas is expected through the day. Some marginal
Small Craft Advisory wind gusts around 25 kts are also possible early, especially
out 20nm, but wind gusts will also be slowly lowering through the
Elsewhere, winds have diminished through lower Delaware Bay this
morning, and thus the Small Craft Advisory was allowed to expire
there. Winds today through Delaware Bay will primarily be between
10 to 15 knots, with seas mainly 1 to 3 feet.
sun-Tue...sub-sca conds are expected.
Tuesday night-Wed...wind and or seas may increase in advance of
approaching low pressure and possible coastal low. Small Craft Advisory flags may be needed
during the pd, but confidence is low at this time.
Marine...Small Craft Advisory until 1 am EST Sunday for anz450>455.