Area Forecast Discussion
Issued by NWS Mt. Holly, NJ-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KPHI 180917
Area Forecast Discussion
National Weather Service Mount Holly NJ
417 AM EST Sat Feb 18 2017
A warm front will lift north of the area today. A cold front is
expected late tonight into early Sunday as an area of low
pressure passes well to our north. Another cold front is
forecast to push through the area early Monday, then high
pressure moves into the area later Monday into Tuesday, before
moving offshore Tuesday night. A weakening frontal is expected
to move across the area early Wednesday. Another frontal
boundary is forecast to approach the area Thursday and stall
near the area through Friday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
It won`t feel much like a February day today! Warm front should
lift from southwest to northeast through the first half of the
day. I favored the warmer NAM MOS guidance for highs today as
guidance has underestimated warm air advection with two recent
events. The one exception to this is across the southern Poconos
and far NW NJ where a snow pack remains (at least for now).
Forecast max temperatures range from the upper 40s across the
southern Poconos to upper 60s in southern Delaware. This is 10
to 20 degrees above normal, but still quite a ways off from
daily record highs. Forecast highs are still 8 to 15 degrees
below the record highs.
Behind the warm front, expect southwesterly winds to pick up
slightly, to around 10 KT, and continue through the day time
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
Winds should shift from southwesterly to westerly overnight,
resulting in weak downslope low level flow. That, combined with
the moisture advection, will limit radiational cooling. Lows are
forecast to be 15 to 25 degrees above normal, ranging from the
mid 30s to upper 40s.
A closed mid level low, currently over OK and AR is expected to
cross VA and Delmarva late tonight. However, it is expected to
fill and weaken today and tonight as it does so. Thus, we are
not expecting the same widespread convection currently on the
front side of this low. However, isolated rain showers will be
possible generally south of Philly as the low crosses Delmarva
.LONG TERM /SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --On Sunday, the cold front that affects the area overnight
Saturday will push through the area. Any precipitation
associated with this boundary will end before daybreak, and a
dry forecast is expected Sunday through Sunday night. Sunday is
forecast to be a warm day, and several places could get within
a few degrees of normal. However, no one is expected to break
any records at this time.
A back door front is forecast to push southward through the
area early on Monday before high pressure builds across the
area later Monday into Tuesday. Cooler conditions are expected
Monday and Tuesday as compared to Sunday, but will remain above
A warm front may pass across the area Tuesday into Tuesday
night as high pressure shifts offshore. Dry weather should
continue on into Tuesday.
A cold front is then expected to approach the area Tuesday night
and pass through during the day Wednesday. Precipitation may
start overnight Tuesday as a short wave/vorticity impulse slides
across the area. If preciptaiton starts early enough, there
could be a wintry mix across the far northern areas, mainly
along and north of I-80 corridor. Guidance indicates the
precipitation beginning to dissipate as it approaches the east
coast as the front moves through the area. So we`ll keep a
chance/slight chance for isolated showers across the area
Tuesday night into Wednesday.
Another front is forecast to approach the area Thursday, then
stall near the area through Friday. There is a chance that some
scattered showers could develop overnight Thursday into Friday
as a couple of short wave/vorticity impulses move across the
area. However, the best chance for precipitation looks like
Saturday as a stronger frontal boundary moves into the area.
-- End Changed Discussion --
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
VFR conditions expected. Only high cirrus clouds are expected
through most of the TAF period. Clouds may thicken and lower to
around 10000 ft AGL near 06Z.
Southwesterly winds will increase to around 10KT through the
day time hours, before dropping off again after 00Z.
Sunday-Tuesday...Generally VFR expected. CIGS may approach MVFR
at times Sunday night into Monday morning. Gusty winds 15-20
knots during the day.
Tuesday night-Wednesday...Conditions lowering to MVFR or IFR
overnight into Wednesday morning with a chance of showers.
Winds and seas should stay below SCA criteria. Gusts above 20kt
are possible late this afternoon and this evening, but winds
are expected to remain below 25kt.
Sunday-Monday...Generally sub Small Craft Advisory conditions
expected, although winds may approach advisory levels across the
northern New Jersey coastal waters overnight Sunday into Monday
Monday night-Wednesday...Sub Small Craft Advisory conditions
expected although winds may gust up to 20 knots at times.