Area forecast discussion
National Weather Service Mount Holly New Jersey
539 am EDT Sat may 25 2013
Synopsis...
strong low pressure east of Cape Cod will drift northward into the
Maine on Sunday. It then will slowly weaken Monday over the Maritimes
as high pressure moves into the Middle Atlantic States. A warm front
develops over the Delaware-Maryland-Virginia Tuesday and slowly lifts northeast of
our area by late Wednesday. Thereafter... summerlike Bermuda high
pressure should be our primary weather influence Thursday into
next weekend.
&&
Near term /until 6 PM this evening/...
low pressure continues to circulate over the New England waters...while
slowly deepening. High pressure is to the west over the upper Great
Lakes and Ohio Valley. The northwest flow between these systems will cause
winds to be gusty from the northwest today. Wind gusts of 25 to 30 miles per hour
will occur at times. Clouds and a few showers will linger North/East
this morning before diminishing. Partly cloudy skies South/West
will become mostly clear during the morning. High temperatures will
remain well below normal for late may with highs middle 50s to low
60s north and low to middle 60s elsewhere. This would be 10 to 15
degrees below normal.
&&
Short term /6 PM this evening through 6 am Sunday/...
the low across New England will continue to bring cooler and drier
air across the region. High pressure will inch eastward from the
Ohio Valley. Skies will be mainly clear across the area tonight. A few
lingering clouds far North/East should dissipate this evening. It
will remain breezy with northwest winds 10 to 15 miles per hour with some g20
miles per hour early. Low temperatures (based mostly on mav mos) will dip into
the upper 30s to low 40s north and middle 40s to low 50s south.
Probably no threat of any frost far north...due to the continuation
of light-moderate winds overnight.
&&
Long term /Sunday through Friday/...
500mb: an unusually cold strong closed low will be lifting northward from
Maine on Sunday with a large strong very warm ridge building eastward
from the Midwest on Monday and Tuesday then becomes locked in along
the middle Atlantic coast for the end of the week and possibly beyond.
Temperatures: calendar day average temperatures nearly 10 degrees below normal
on Sunday will warm to near 5 degrees below normal Monday and Tuesday...
and then from Wednesday Onward...a warmer than normal period occurs
as the Summer ridge replaces this currently out of season cold damp
blustery weather. Temperatures could average almost 10 degrees above
normal Thursday and Friday.
Frost: small chance for a touch of frost in Monroe County early
Monday morning. Severe weather potential statement.
Heat: greater potential for a heat wave beginning Wednesday or Thursday into the
start of the weekend. Not yet in severe weather potential statement. Need a little more continuity
for this day 5-7 or day 6-8 potential hot spell.
The dailies below...
Sunday and Monday are based on 50 50 blended GFS/NAM MOS guidance
and then Tuesday is 00z/25 GFS mexmos. Tuesday night Onward through
Friday is based primarily on the 0543z/25 NCEP extended guidance
which was modified upward on the daytime temperatures where the GFS mexmos
or 00z/25 European model (ecmwf) 2m temperatures were warmer than HPC. All this data is
checked against ensemble pop guidance as well as the European model (ecmwf) mass
fields and their 2m temperatures.
Sunday...partly sunny day and blustery. Northwest gusts 25-30 miles per hour. Clear
and chilly at night. Low probability isolated frost Poconos. Despite climatology
impact on the guidance...which might forecasting the nighttime temperatures
a tad on the mild side Monday morning...it just appears the night is
too short after a daytime maximum in the 60s to permit frost.
Monday...mostly sunny. West-northwest g to 15 miles per hour. 35 to 40 degree diurnals
in the Countryside.
Tuesday into Wednesday...a small warm frontal shower risk but overall
I think acceptable for outdoor activity. Variable clouds.
S-SW g 15 Tuesday and west-southwest on Wednesday.
Temperatures Thursday and Friday could run 3 degrees warmer than what we are currently
forecasting in the 330 am kphi forecast package. It is day 6-7 but it looks hot
in the 90-93f range. For now a more conservative around 90f forecast.
Thursday...sunny and probably hot. SW g 15. 16-17c at 850mb
Friday...partly sunny and probably hot. For now the 12z/24 European model (ecmwf) idea
of a backdoor cool front was squashed by its 00z/25 deterministic
run and the gefs argues strongly against a backdoor. SW g 15 miles per hour.
16-17c at 850mb.
&&
Aviation /10z Saturday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Low pressure at the surface and aloft will continue to spin about across
New England today and then slowly move away tonight. This system
will continue to produce abundant cloudiness North/East with
improving conditions arriving from the South/West through the day.
Even with the clouds (and early morning showers)...conditions are
expected to remains VFR at the terminals. Winds will be gusty today
and into early tonight with northwest winds 10 to 20 g25
early...then 15 to 25 g30 knots from late morning into the early
evening. Winds gradually subside overnight Sat night. Skies Sat
night into sun will be mostly clear.
Outlook...
Sunday...mainly VFR conditions with scattered-broken clouds at or above 5000 feet.
Gusty northwest winds to near 25 knots during the day diminish at
night as skies clear.
Monday...VFR generally clear with west northwest winds g near 15 knots.
Tuesday through Wednesday...mostly VFR conditions. Small chance sub-
VFR ceilings/visibilities in showers Tuesday night with a warm front lifting through
the region.
&&
Marine...
we will put up the gale at the northern two coastal zones with the
400 am coastal waters forecast issuance. The gale flag will continue though the
today/tonight period with the decent pressure gradient across the
region and the cold northwest flow. The only weather of significance
in the short term will be some morning clouds/showers across the New Jersey
coastal waters which will gradually erode from S to north today. Winds
will decrease a little tonight...with gales probably being converted
back to Small Craft Advisory flag overnight.
Outlook...
leftover Small Craft Advisory winds and seas Sunday (after the gale subsides) then
no headlines anticipated Sunday night through at least early
Wednesday. There may be an Small Craft Advisory late Wednesday but its a small chance
at this time and capped seas at 5 feet due to warm air advection. That 5 feet late Wednesday forecast
may also be too high by a foot or so.
&&
Tides/coastal flooding...
the low water advisory across del Bay will continue through 800 am.
The departures overnight have gone down to -1.5 to -2.5 below normal
and they haven't changed much as the low tide has arrived across the
Bay. If it appears that these departures will carry up into the del
river...an Special Weather Statement will be issued shortly.
&&
Rip currents...
there is a moderate risk of rip currents forecast for today and probably
tomorrow. Thereafter...for Memorial Day and Tuesday the outlook is for a
low risk for the formation of rip currents as winds and swells diminish.
SSTs along the coast are quite variable...especially New Jersey where its
still chilly waters near Atlantic City.
&&
Climate...
the monthly average at phl should come in about 1 degree above
normal based on the latest projections.
&&
Phi watches/warnings/advisories...
PA...none.
New Jersey...none.
Delaware...none.
Maryland...none.
Marine...Gale Warning until 2 am EDT Sunday for anz430-431-450>455.
Low water advisory until 8 am EDT this morning for anz430-431.
&&
$$
Synopsis...drag
near term...O'Hara
short term...O'Hara
long term...drag
aviation...drag/O'Hara
marine...drag/O'Hara
tides/coastal flooding...
rip currents...
climate... 538
