Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Mount Holly New Jersey
407 am EDT Wednesday Apr 16 2014

a strong cold frontal system will continue moving offshore today
with high pressure building into the region for this afternoon and
tonight. The high pressure system will move into New England on
Thursday. By Friday another cold frontal boundary will approach the
region moving through the region on Saturday. High pressure will
once again move back into New England for Sunday and Monday as a low
pressure system develops in the plains. This low pressure system
will bring a warm front through the region Monday night and a cold
frontal boundary through the region Tuesday.


Near term /until 6 am this morning/...
all rain, sleet, and snow has moved offshore this morning and we
are left with partly to mostly cloudy skies early this morning.
The only exception to this is some lake effect snow
showers/flurries across the Poconos within the northeast flow.
These could continue for a few hours, but as the winds begin to
swing more north then northeast, the flow off the lakes will get
cut off and end the snow shower chance. We will keep isolated snow
showers for a few hours across the Poconos this morning.

High pressure will build across the area today allowing dry air to
settle across the area through the day and skies will be clearing
through the morning into the afternoon. Winds will be gusty through
the morning hours into the early afternoon, but as the high builds
over the area, the winds will lighten and the gusts should drop off.
Temperatures today will not be able to warm much as 925 mb
temperatures top out around -1 to -2 degrees celsius. MOS numbers
were fairly close, so we used a blend of mav/met MOS, MOS guide, and
European model (ecmwf) grids. This yields afternoon highs well below normal.

Short term /6 am this morning through 6 am Thursday/...
high pressure will build across New England overnight tonight into
Thursday morning, but still extend southward across our area. This
will keep dry weather across the area through tonight and Thursday
morning. MOS numbers were fairly close, so we used a blend of
mav/met MOS and MOS guide. This yields overnight lows well below
normal once again. The freeze watch will remain in place as
temperatures are expected to drop to or below freezing by Thursday
morning. We will keep frost in the grids as winds will be lighter
than last night/this morning, but there may still be enough of a
breeze in most places to prevent widespread frost from occurring.


Long term /Thursday through Tuesday/...

Thursday and Thursday night: looks to be a relatively quiet period
under northeasterly flow from the frontal boundary offshore and high
pressure to our north. The one concern may be some low clouds and
drizzle that advect in from the ocean along the immediate coast. For
now left it less than a slight chance for the far southeast portions of the
County Warning Area in line with the sref and 00z NAM/GFS. Thinking the frost threat
may be more limited this period due to several factors such as cloud
cover and some wind with slightly warmer temperatures. Took frost
out of the grids in this timeframe though some isolated frost can
not be totally ruled out. Think once again the raw modeled two meter
temperatures will be to cool with the 850 mb temperatures over 0c. Went
close to mav/met guidance for temperatures during the day then
went slightly warmer than mav/met at night due to clouds.

Friday through Saturday night: low clouds and some spotty showers/
drizzle may still advect in for coastal regions on Friday going more
in line with the NAM/GFS and sref. Though confidence on the extent
on any potential low clouds and drizzle is lower than ideal. This
should break up by Friday night along the coast with inland sections
remaining partly cloudy. It appears that a frontal boundary
will move from the Great Lakes through the region as a low pressure
system tracks along the southeast coast staying separate,
preventing a larger impacting event. Moisture ahead of the frontal
passage on Saturday looks limited so only a few hundredths for
quantitative precipitation forecast. Pretty tight spread among models and mex guidance with
temperatures in these periods.

Sunday and Sunday night: looks like a good weather day across the
region. With plentiful sunshine went more toward mex/wpc guidance on

Monday through Tuesday night: next system will be a cold front
approaching from the west by Monday night will include a chance of
showers from Monday night through Tuesday night. Went more in line
with the 00z GFS in this period as the new 00z European model (ecmwf) has a anomalous
cut-off low over the southeast United States which acts a block for
the front. Did go lower than wpc guidance for temperatures on Tuesday
given potential rainfall.


Aviation /08z Wednesday through Sunday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

VFR conditions will prevail through the taf period. Gusty northwest
winds will diminish through the day as high pressure builds across
the area. Winds will become more northeast later this evening and
overnight as high pressure builds across New England.

Thursday through Friday night... mainly VFR, some scattered low
ceilings Thursday night and Friday morning southeast of kphl.

Saturday: mainly VFR, possible brief periods of MVFR in scattered

Saturday night and sunday: VFR.


the Gale Warning will remain in place with no changes to the ending
time, although we may be able to cancel earlier than expected later
this morning. Winds will remain gusty across the waters until high
pressure builds across the area and helps diminish the winds.
However, winds may remain gusty around 15-20 knots through tonight.
Seas are expected to subside to around 4 feet later today into this
evening, but should build again overnight as a northeast fetch takes
place and will likely increase seas once again to 4-6 feet.

Thursday through Friday night: Small Craft Advisory seas throughout the period on
the ocean and some Small Craft Advisory gusts likely Thursday.

Saturday and sunday: sub Small Craft Advisory seas and winds.



Phi watches/warnings/advisories...
PA...freeze warning until 9 am EDT this morning for paz060-070-071-
Freeze watch from late tonight through Thursday morning for
New Jersey...freeze warning until 9 am EDT this morning for njz012>027.
Freeze watch from late tonight through Thursday morning for
Delaware...freeze warning until 9 am EDT this morning for dez001>003.
Freeze watch from late tonight through Thursday morning for
Maryland...freeze warning until 9 am EDT this morning for mdz008-012-015-
Freeze watch from late tonight through Thursday morning for
Marine...Gale Warning until noon EDT today for anz430-431-450>455.


near term...Robertson
short term...Robertson
long term...Gaines