Forecast Discussion From Mount Holly
000
FXUS61 KPHI 270556
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
156 AM EDT Sat Apr 27 2024
.SYNOPSIS...
High pressure will remain in control of the prevailing conditions
through early next week with low chances of showers and storms.
Below normal temperatures to start eventually rise above normal over
the weekend. A weak system will be a more widespread chance of
storms on Tuesday, although temperatures will remain above normal
through much of next week.
&&
.NEAR TERM /THROUGH TODAY/...
Latest satellite imagery shows some high clouds have filtered
into the region a bit earlier than initially expected. As a
result, our lows tonight are likely in jeopardy of not being
realized by a few degrees in many spots. Only the NJ pine
barrens have cooled substantially before high clouds have moved
in. Some breaks in the clouds are moving eastward towards the
region and could help cool a few spots. While generally
expecting most locations outside the pine barrens to end up a
few degrees warmer than the previous forecast, will maintain the
Frost Advisory as is for now since some patchy frost remains
possible in the most sheltered areas.
Saturday will start mainly clear with skies then clouding over
through the late morning into the afternoon from west to east as
the warm front approaches. There will be some showers
associated with this front approaching from the west but I think
they should be fizzling out as they reach eastern PA since the
low levels will be fairly dry. As a result, we just mention
isolated to scattered light showers in the forecast for Saturday
afternoon over eastern PA and Delmarva extending into adjacent
portions of NJ roughly as far east as around Trenton. The cloud
cover will keep temperatures a bit cool with highs in the upper
50s to low 60s.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
The main story for Sunday into Monday will be the strengthening
ridge across the East Coast. 500 mb heights look to increase to near
580 dam by Monday, values more typical of summertime. At the
surface, high pressure will be centered offshore of the Carolinas,
helping to advect warmer and more moist air into the region. The
result will be much above normal temperatures. Saturday night will
see lows nearer to normal though (mainly in the 40s), as this will
be the transition time between airmasses. Cloud cover will also
limit radiational cooling Saturday night, and winds will be from the
south near 5-10 mph. The warm advection aloft should result in some
isolated to scattered showers overnight, mainly near and north of
Philly.
By Sunday, temperatures will rise well into the 70s to near 80
degrees in many interior locations. The limiting factor for
temperatures Sunday will be how quickly the morning cloud cover
clears out. The cloud cover looks to hang on the longest across the
northern portions of the area, so areas north and east of a line
from roughly Philly to Reading will likely stay in the mid 70s at
best. Some isolated showers are possible in the Poconos, Lehigh
Valley, and NW NJ, but the strong ridging aloft will likely hinder
development. Lows Sunday night will be about 10-15 degrees above
normal, mainly in the mid 50s to near 60 degrees with clearing skies.
Monday will be the warmest day of the stretch with high temperatures
soaring into the mid 80s in most interior locations under partly
cloudy skies. Highs in the more urbanized areas could top out in the
upper 80s, though reading of 90 degrees or higher are unlikely. The
northwest flow will add a downsloping component to the winds and
thus also help to boost temperatures locally near the urban
corridor. The offshore wind will also allow for a notable warmup
even along the immediate coast, with highs getting to the low to mid
70s before the sea breeze kicks in. As the gradient flow weakens and
shifts eventually to the southwest then south, the sea breeze will
likely make significant inland progress into the I-95 corridor and
perhaps even farther inland from there during the evening. This will
cool temperatures off into the 70s and 60s by late evening.
Dewpoints will be near 60 degrees, so the Heat Index won`t be much
different than the air temperature on Monday. No heat headlines are
anticipated.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The very warm weather that was in the short term part of the
forecast spills over into the long term as the upper ridge that
promotes it only gradually moves away later Monday and Tuesday.
Highs Tuesday will be a few degrees cooler than Monday (the warmest
day of the whole forecast period) but still be in the upper 70s/low
80s most places. Temperatures will drop a few degrees Wed thru
Friday but remain in the 70s for highs most places. Cooler temps for
the southern Poconos and near the shore.
There are no widespread precipitation events foreseen during the
long term. There is an opportunity for showers Tue/Tue night as
shortwave energy rides up the backside of the retreating ridge. More
showers are possible Thursday as an upper low and surface fronts
arrive from the west. Pops during the Tue/Thu periods are in the
slight chance or low chance range.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...
Rest of tonight (through 12Z)...VFR. East to southeast winds
dropping to 5 kts or less. High confidence.
Saturday...VFR to start with increasing clouds. MVFR cigs
possible for ABE/RDG/TTN by late day with broken cigs around
5-7kft elsewhere. Southeast to south winds around 10 knots.
Moderate confidence.
Saturday night...MVFR cigs remain possible across ABE/RDG/TTN
with 5-7kft cigs lingering elsewhere. South to southeast winds
less than 10 kts. Moderate confidence.
Outlook...
Sunday through Monday...No significant weather expected. Mainly
VFR with winds near 5-10 kts.
Tuesday/Tuesday night... Mostly VFR. Scattered showers or tstms
possible with lower CIGS/VSBYS.
Wednesday... Mostly VFR.
&&
.MARINE...
Conditions will remain below Small Craft Advisory levels through
Saturday with east to southeast winds generally around 10 knots
and seas 2 to 4 feet.
Outlook...
Saturday night through Monday... No marine hazards expected.
Winds 10- 15 kts and seas 2-4 feet.
Tuesday... Scattered showers/tstms. Sub-SCA expected.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Frost Advisory until 9 AM EDT this morning for PAZ060>062-103-
105-106.
NJ...Frost Advisory until 9 AM EDT this morning for NJZ001-007>010-
012-013-015>022-027.
DE...None.
MD...None.
MARINE...None.
&&
$$
SYNOPSIS...Staarmann
NEAR TERM...Fitzsimmons/MPS
SHORT TERM...Staarmann
LONG TERM...OHara
AVIATION...Fitzsimmons/MJL/MPS/Staarmann
MARINE...Fitzsimmons/Staarmann
NWS PHI Office Area Forecast Discussion
