Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
939 PM EDT Thursday Jul 2 2015
weak high pressure will build to our north tonight into Friday as
another wave of low pressure moves along a stalled front to the
south. Another area of high pressure will then move into the
region through the Holiday weekend. A cold front will cross the
area by Wednesday.
Near term /until 6 am Friday morning/...
a frontal boundary remains stalled to our south near the Virginia-NC
border and to our east just off the northern middle-Atlantic coast. The
evening water vapor satellite loop captured a shortwave trough
approaching the middle-Atlantic coast. The last band of showers with
this shortwave trough will move off the New Jersey coast late this
evening. There may be an isolated leftover shower overnight
especially in the Delaware-Maryland-Virginia and near the coast but for the most part
it will dry out.
The extent of fog development should be limited by the cloud
cover that is currently in place. However, breaks in the clouds
are expected to develop from northwest to southeast late tonight. If more
persistent breaks occur than currently expected, then the coverage
of fog may be greater, especially if The Breaks occur across the
same areas where the ground is still wet from today's rainfall.
Short term /6 am Friday through 6 PM Friday/...
upper level short wave ridge moves over head bringing mostly dry
conditions, although still a few showers may develop along the old
frontal boundary and move northeast into our region. Even though
there should be less clouds tomorrow (especially in the northwest),
still expect temperatures to be slightly below normal given the
relatively cool air mass still in place.
Any mention of thunder was removed from the forecast on Friday.
Forecast soundings for tomorrow are stable even in our southern
Long term /Friday night through Thursday/...
for the start of the extendd pd, a stalled front will be located S
of the region. Low pressure is expected to move along the front and could
trigger some rain showers/thunderstorms and rain Sat into Sat evening. The best chances are over
southern area. It still appears that any activity should be scattered and over
with by sunset or shortly thereafter. Sat looks to be the worst of
the two weekend days, if we had to pick one.
By sun, high pressure begins to build in and sun should be dry over
most, if not all of the area, continuing into Sun night.
The models have some disagreement as we move into Monday. The GFS is
dry. The CMC is also dry. The European model (ecmwf) tries to develop another wave
of low pressure and is subsequently wetter than the other models. Right
now, the European model (ecmwf) is the outlier. But, felt compelled to at least
introduce some very low probability of precipitation. However, confidence is very low. The
European model (ecmwf) keeps things wet into Tuesday while the other models are dry.
Then, by Wed, models come into better agreement again as a cold front
approaches from the W, precipitation would probability linger into Thu, but
there is still a week for the models to Iron out any diffs in
With the exception of Sat, which looks to be on the cool side,
temperatures should be near or slightly above normal through the period.
Aviation /01z Friday through Tuesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Low clouds have eroded at Acy/miv around sunset this evening as the
rain has moved out of the area. There is a potential for low
clouds to redevelop in these areas overnight and early Friday
morning. Patchy fog may develop at the terminals overnight,
especially at locations that received rainfall today. Winds will
be light and variable.
Mainly VFR after 12z Friday, though lower clouds may persist into
the late morning along the coast (acy). There is a slight chance
for showers; too small to mention in any tafs at this time. East
winds may become southeasterly during the afternoon but less than
Friday night and Sat...generally VFR. However, there will be a chance of
MVFR/IFR conds Sat afternoon/evening in scattered showers and possible thunderstorms and rain. Best chances
are for the southern taf sites. MDT confidence.
Sat night through Tuesday...VFR conds expected sun and Tuesday. High
confidence. Less certainty for Mon, due to model disagreement. Could
be a better chance of rain showers/tsra, but confidence is much lower.
winds and seas should stay below Small Craft Advisory criteria tonight and Friday.
Friday night through Sat...depending on the strength and track of low
pressure along stalled front, Small Craft Advisory may be needed, especially on the southern
waters. However, latest guidance indicates both wind and seas will
remain below Small Craft Advisory criteria during this period.
Sat night through Tuesday...no marine flags anticipated during this period.
the onshore flow combining with rather robust Spring tides
following the full moon (which occurred this past wednesday) might
cause minor tidal flooding with the evening high tide cycles on
Friday (the more likely one) and Saturday. However, latest guidance
indicates we should stay just below minor tidal flooding criteria
at this time.
the combination of an onshore flow and the full moon is expected
to increase the strength of rip currents on Friday and Saturday,
before conditions improve on Sunday. Local regression guidance
shows the rip current risk for the New Jersey beaches to be right at the
cusp for moderate on Friday.