Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
FXUS61 KPHI 300432
Area Forecast Discussion
National Weather Service Mount Holly NJ
1232 AM EDT SAT JUL 30 2016
Scattered showers and thunderstorms with locally heavy rainfall
will re-develop Saturday afternoon and linger into Monday with low
pressure and a frontal boundary hung up across the mid Atlantic
States. High pressure will then bring mainly dry and less humid
weather for the remainder of the next work week.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Showers associated with an area of convergence continued from the
lower Susquehanna River Valley into Berks County around 12:30 AM.
They will continue to drift eastward and they should dissipate by
3:00 AM. Otherwise, we are anticipating a clear to partly cloudy
sky over our forecast area.
The wind should remain light and temperatures are expected to
drop into the 60s up north and into the lower 70s elsewhere. The
light wind and a fair amount of low level moisture should result
in some patchy fog, especially at locations that received heavy
rainfall over the past day or so.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SUNDAY/...
The upper level trough becomes more defined as it moves closer to
the region. As a result, should see an area of precipitation move
into the region (exact timing is uncertain by the higher chances
look to be in the afternoon). As far as hazards, the primary
hazard appears to be heavy rain. Precipitable water values are
well above normal, and storm motions look to be quite slow (<15
kts) as the flow is weak. However, with limited focus for surface
convergence (at least over our immediate area), not confident that
there will be a widespread flooding threat. Thus, not planning to
issue a flash flood watch at this time.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
* Scattered showers and thunderstorms Saturday night/Sunday with the
potential for heavy rainfall and a very localized flood threat
* Scattered showers/thunderstorms linger Monday, otherwise much of
the next work week will be dry and less humid
Saturday night and Sunday...
A couple of additional shortwaves will move across our region
along with a frontal boundary in the vicinity. The result will be
periods of scattered showers and thunderstorms Saturday night into
Sunday. Specific timing is uncertain at this point, but Pwats of
2+ inches will bring the potential for locally heavy rainfall.
While any flood threat looks very localized, weak low level wind
fields may result in slow movement and back building of any
thunderstorms, so that will need to be watched. Weak wind fields
will also result in a low overall risk for severe weather, but a
few strong storms can not be ruled out.
Guidance has trended a bit slower over the past 24 hours. Frontal
boundary will still be across our region along with another piece
of shortwave energy moving in on Monday. The result will be the
continued chance for scattered showers and thunderstorms.
Tuesday Through Friday...
Large high pressure will be building across the mid Atlantic
States. While we can not rule out a few lingering showers Tuesday,
mainly dry and less humid weather is expected through Friday. High
temps will mainly be in the 80s for much of the next work week.
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...VFR with sct clouds aoa 6000 ft. Showers lingering
around KRDG. Light wind becoming calm with a chance of patchy fog
nw NJ and in the seabreezed areas of coastal NJ and coastal DE.
Saturday...cirrus ceilings lower to sct-bkn aoa 3500 ft during
the afternoon with showers and isolated tstms with heavy rain
spreading newd. showers could begin to move into the western TAF
sites (KABE, KRDG) after 15Z and Delaware Valley TAF sites (KPHL,
KPNE, KILG, and KTTN) after 18Z. east or southeast wind.
Saturday night through Monday...Moderate to high confidence. VFR
dominates but periods of lower conditions expected in scattered
showers and thunderstorms.
Tuesday and Wednesday...Moderate to high confidence in mainly VFR
Winds and seas should remain below SCA criteria through Saturday.
Mainly variable winds overnight becoming predominantly southeast
Saturday night through Wednesday...A wave of low pressure may
result in a brief period of marginal small craft advisory seas
across our northern waters Sunday afternoon/early evening.
Otherwise, weak pressure gradient should keep winds/seas mainly
below small craft advisory thresholds through Wednesday. Main
concern for mariners will be the threat of scattered thunderstorms
Saturday night through Monday.
The probability for the development of dangerous rip currents on
Saturday is low. Sunday may become a moderate risk along parts of
the central and northern NJ shore, dependent on the strength of
the onshore flow. A longer period 2 to 3 foot se swell may develop
around Wednesday August 3.
PHL: heading for top 8 warmest July on record. July avg temp for
PHL will be about 80.9 or 81.0F, 8th warmest July in the period of
record since 1874. if its 81.1...it would be tied for 7th.
ACY: 8.77 inches as of 5 PM ranks 6th wettest July on record with
its monthly record of 13.09 set in 1959. The por is back to 1874.
ACY entire July normal rfall 3.72
Still opportunity for ACY to rise in the monthly rainfall
ranking, though WPC has only about .75 for the rest of the month.