Scientific Forecaster Discussion
fxus61 kphi 210634
Area forecast discussion
National Weather Service Mount Holly New Jersey
234 am EDT Sat Oct 21 2017
high pressure centered over the area will move offshore late
today but continue to influence our weather into Monday. A cold
front approaching from the west is expected to arrive on Tuesday
night. Low pressure is anticipated to develop over New England
and its coastal waters late in the week as another area of high
pressure noses into our region from the southwest and south.
Near term /through today/...
early this morning...clear or mostly clear. Calm or light wind.
Patchy fog possible in some of the river valleys toward dawn.
The 1230 am estf lowered some of the mins several degrees in
the Countryside. Lows will have been 0 to 5 above normal.
Today...sunny. Light wind becoming southeast during the afternoon.
High temps similar to or a couple of degrees warmer than ydy.
Used a 50 50 blend of the 00z/21 GFS/NAM except straight warmer
GFS 3 hourly and Max T today, trimmed a degree over i95. Max
temps about 10 to 15f above normal. Looks to ME like 75-59
virtually everywhere i95 corridor northwestward with support
from the 00z/21 ec 2m temp fcst at 18z today. It will be slightly
cooler high terrain. The 72 we're fcstg at kmpo is 5f short of
the record of 77 - 1959. Effective sea breezing along the coast
this aftn with water temps in the 60s...which are still
significantly above normal for this time of year. Max temps
today are fcst generally 10-15f above normal, greatest positive
departures i95 northwestward.
Short term /tonight/...
clear and nearly calm but patchy fog may form toward dawn Sunday,
especially se of I-95. The 330 am fcst is a 50 50 blend of the
GFS/NAM MOS with Countryside temps lowered 2-3f below the
blended guidance and not much above this mornings mins...ranging
from zero to +10 of normal depending on location.
Long term /Sunday through Friday/...
the axis of the mid level ridge is forecast to pass overhead on
Saturday night. Meanwhile, a sharp trough is expected to be
located over the middle part of the country during the weekend.
A mid level low is anticipated to develop over the south central
states on Sunday.
A re-enforcing mid level trough is expected to drop over the
eastern states for the mid week period. The trough is forecast
to pull the mid level low east then northeastward and over our
region on Tuesday. The long wave trough should begin to lift to
our northeast late in the week.
At the surface, high pressure moving out to sea should maintain
some influence over our weather for Sunday and Monday with no
precipitation expected. However, there should be an increase in
cloud cover during the period. A return southerly flow may
result in the development of low clouds and perhaps some fog
from late Sunday night into Monday morning.
The end of our current dry spell is anticipated to arrive on
Monday night. Showers ahead of an approaching cold front should
begin to move into our region at that time. We are expecting an
increasing chance of showers on Tuesday. As the surface cold
front nears our area and as the remnants of the mid level Low
Pass overhead there should be added lift. As a result, there may
be a period of moderate and perhaps briefly heavy rain along
with isolated thunderstorms on Tuesday afternoon and into
Tuesday evening. There is the potential for a half inch to an
inch of rain in spots.
The cold front and the precipitation associated with it should
pass off the coast on Tuesday night.
Low pressure is forecast to develop along the departing front
off the middle Atlantic coast. The low is expected to lift over
New England and its coastal waters late in the week. The system
may push clouds and showers back into our region from the
northeast for the period from Wednesday night into Thursday
night. Otherwise, surface high pressure will likely try to build
into our region from the southwest and south.
Daytime temperatures will remain about 10 degrees above normal
on Sunday, Monday and Tuesday. Readings are forecast to drop
back to near normal levels for late October on Thursday, Friday
Aviation /06z Saturday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
Through today...VFR with a few cirrus, especially this afternoon.
Light northwest wind trending northeast later this morning and
then southeast during this afternoon.
Tonight...VFR with some cirrus. The IFR St/fog may develop southeast
of I-95 toward dawn Sunday.
Sunday night and Monday...low clouds and fog are possible from
late Sunday night into Monday morning. Otherwise...mainly VFR.
Monday night through Tuesday night...conditions lowering to
MVFR and IFR in showers. Isolated thunderstorms and moderate to
heavy rain are possible on Tuesday afternoon and Tuesday
evening, along with a south wind gusting around 25 to 30 miles per hour.
Wednesday...conditions improving to VFR.
winds and seas well below Small Craft Advisory criteria through tonight.
Light northwest winds 5-10 kt with a few gusts around 15 kt over the
waters will veer over the next 24 hours, becoming north this morning,
east around midday and then S-southeast late today and tonight.
Seas in our coastal waters of around 2 ft through tonight.
Fog may develop on the coastal waters toward dawn dawn Sunday.
Sunday through Monday night...no marine headlines are anticipated.
Tuesday and Tuesday evening...a Small Craft Advisory may be
need for southerly wind gusts of 25 to 30 knots. Waves on our
ocean waters may build to 6 to 8 feet.
Late Tuesday night and Wednesday...a Small Craft Advisory may
be needed on our ocean waters for wave heights of 5 to 6 feet,
even as the wind becomes westerly and diminishes to 10 to 15
relative humidity values are likely to drop to around 25% this afternoon but
light winds will limit the risk for a rapid rate of spread of
the values below are the October departures from normal through
the 20th (yesterday).
This climate section will be expanded by 4am as we reevaluate
the month of October temperature projection.
44091 buoy drifted away from its mooring and was recovered. Its
rts date is unknown.
near term...drag 235
short term...drag 235