Area Forecast Discussion
Issued by NWS Mt. Holly, NJ-- Remove Highlighting --
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FXUS61 KPHI 170801
Area Forecast Discussion
National Weather Service Mount Holly NJ
301 AM EST Tue Jan 17 2017
Low pressure is forecast to pass across the Great Lakes on today
with a secondary low developing near Long Island on tonight.
The system is anticipated to move out to sea on Wednesday. High
pressure should follow for Wednesday night through Thursday night.
Low pressure is forecast to move across the Ohio River Valley and
the eastern Great Lakes on Friday with a secondary low developing
off the Middle Atlantic coast on Friday night. High pressure is
expected to build into our region from the north for the weekend.
A broad area of low pressure is anticipated to approach from the
southwest early next week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
245 AM: not much happening except as modeled for the Delmarva and
then entering e PA 09z-12z. will keep portions of advy in e pa but
dropping Morris in NNJ. Final decision at 330 AM. My thinking is
that this is primarily an elevated ice event mainly
bridges/overpasses/ trees and branches later this morning through
tonight fm northern Sussex County into northwest Monroe county.
Yes there can be spotty elsewhere this morning but i dont see
widespread icing, at least not at this 245 am writing due to lack
of organized qpf while wet bulbs near freezing. Will ck new 06z
NAM at 08z and 08z temps and go from there.
Still no icing groups at any metar sites (I group) in our area
through 07z, which means, little if any icing, so far. We have
messaged FB for any reports. The 00z/17 GFS/NAM keep primary
measurable prior to 15z down on the Delmarva and s NJ. That
probably means little in the way of overnight icing and the
question thereafter, where to keep the advy on Tuesday. Wet bulbs
still say icing possible in portions of the forecast area but as
of this writing...am thinking only Monroe County Sussex County
high terrain will have any substantive icing once rain begins in
earnest between 15z-17z. Its a close call on all of this. Light
So, rain overspreads the entire area 15z-18z then may quit at
times Delmarva late day or evening. A cold rain. Light wind trending
northeast, north of I-78 as low pressure forms in central NJ late
in the day while winds are southeast over the Delmarva trending
south late in the day with max temps there late in the day.
Basically blended the 0z/17 EC 2m temps with the 00z/17 MAV MOS
temps. Met and MOS temps as well as 2m temps on the models are
substantially too cold early this morning and not used prior to
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
Cold rain and drizzle north of I-78 while s of I-78... periods of
rain and drizzle diminish, especially Delmarva where there may be
9 hours of rainfree weather. Still a risk of glazing vcnty KMPO
and High Point NJ but no advy extension attm.
Fog may become a problem, especially late and especially south of
00z/17 ECMWF 2 m temps blended with the colder of the avbl NCEP
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
The long term part of the forecast will feature a continuation of
mild temperatures for mid-late January. High temperatures will be
mostly around 10 degrees above norma thru the period.
There will be several wet weather systems. The first will be across
the area Wed morning, but pops will decrease thru the day as low
pressure and its fronts pass east of the region during the afternoon.
This will be followed by a period of dry weather from wed night thru
Low pressure will move into the upper Great Lakes region Friday and
its attached warm front will approach/cross the region Fri into Sat.
A period of showers will accompany the feature. Overall rainfall
amts will be rather light however.
A stronger system will move slowly across the Mississippi/lower Ohio
Valley region Sun-Tue next week. This will draw moisture northward
from the Gulf of Mexico. It appears that a decent rainfall event
will occur across our forecast area Mon-Tue with this system.
Rainfall amts of 1 to 2 inches could occur across our area. Pops are
already in the low likely category for this time period. We will
leave it as is for now. Latest GFS/EC are showing good agreement with
the broad scale timing/location of the system.
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Early this morning...Cigs 1500-6000 ft...mainly in the 1500-3000
ft range. light south wind. Vsby will decrease to mvfr in showery
rains toward 11z vcnty KILG.
Today...MVFR Cigs lower to IFR during midday with vsby decreasing
to MVFR in periods of rain. light wind...trending northeast or
north KABE/KRDG while light south to southeast elsewhere.
Tonight...Widespread IFR conditions expected with rain diminishing
to drizzle and eventually fog as cigs lower through the night.
Light wind trending north to west entire area overnight.
Wed...Morning clouds/showers will yield to improving cigs/vsbys.
Wed night thru Fri morning...Mostly VFR expected.
Fri afternoon thru Saturday...Lower cigs/vsbys possible. Showers.
Sat afternoon-Sat night...mostly VFR.
No headlines through Tonight. Wave heights will still be around a
foot or 2 with winds under 10 knots, fairly quiet on the waters.
Wed thru Sun...Sub-SCA conditions. Showers Wed morning, Fri-Sat
Sun night...SCA developing with low end Gale possible. Showers.
PA...Freezing Rain Advisory until 7 PM EST this evening for PAZ054-
Freezing Rain Advisory until 10 AM EST this morning for PAZ062.
Freezing Rain Advisory until 10 AM EST this morning for PAZ060-
NJ...Freezing Rain Advisory until 7 PM EST this evening for NJZ001.
Freezing Rain Advisory until 10 AM EST this morning for NJZ007.