Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
FXUS61 KPHI 270731
Area Forecast Discussion
National Weather Service Mount Holly NJ
331 AM EDT FRI MAY 27 2016
High pressure off the middle Atlantic coast will settle over our
region through the weekend, gradually giving way to a cold front,
that is expected to move through our area Tuesday. Canadian high
pressure is expected to settle over our region by mid week, while
a persistent area of low pressure lurks off the southeast coast.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
300 AM ESTF: Showers in northeast Pa were moving slowly for northwest
NJ during the predawn hours and should move out of our CWA of northwest
NJ area by 7 am or so. PWAT is building and so slow moving showers
means torrents. Hamburg in Berks County earlier had 0.4 inches.
Today...Confidence on where and when any showers and tstms is
below average. Thinking mainly north of I-78 and mainly this afternoon.
pwat of 1.7 inches and slow ene movement of 15 to 20 kt could mean
the issuance of flood advisories for poor drainage street
flooding this afternoon in a few locations...maybe Morris County
is the focus?
Otherwise very warm and more humid with a potential for D2 of 90F
temps at KABE/KPHL/KPNE/KTTN/KACY/KGED/KESN. Depends on how much
sunshine and how much non marine influenced flow. Best chance for
90F temps is near and north of I-78 possibly extending down to
KPHL? Airmass is as warm as ydy with higher dewpoints. More cloud
cover may make it more difficult to maximize heat potential but
for now we have issued 90F Philly north. This again is above all
available NCEP guidance which includes the Super and National
blends which were biased low with respect to reality. EC also
indicates says about the same as ydy. this would mean max temps 10
to 15F above normal.
Max heat index today...roughly in the lower 90s...or about 5 to 6f
warmer than yesterday...because of the higher dewpoints.
South to southwest wind with afternoon gusts 15 mph.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
Any convection should diminish and end by midnight. Otherwise fair
and mild. Looks like haze and/or patchy fog early tomorrow morning
with the fog in your typical spots...northwest NJ and also vcnty
KRDG and KMIV. Min temps about 10 to 15F above normal.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
The main story will continue to be above average temperatures
thru Sunday with high temperatures near 90 degrees, as well as
uncomfortable humidity levels into early next week. Temps will
remain above average into the middle of next week
The main uncertainty will be the interaction between an approaching
cold front early next week and an early season tropical/sub-tropical
system modeled to develop in the Bahamas. The models continue the
trend of drawing a plume of moisture northward along the east coast,
with PW values nearing 2.00 inches, or 2 to 3 Standard Deviations
above normal by Monday. With the approach of a cool front and
weak steering currents aloft, there is the potential for heavy
downpours on Monday. Otherwise, there is a chance of diurnally
driven showers and thundershowers Saturday and Sunday. For
Saturday, this activity should be focussed northwest of I-95,
while Delmarva may see an increase in activity by late Sunday.
A cold frontal passage is anticipated Tuesday, with a drying
trend for Wednesday and Thursday. But with low pressure off the
southeast US coast, this front may get hung up close to our
region, which would lead to a more pessimistic forecast.
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Early this morning through 12z...VFR with showers vcnty kabe
ending by 08z. Light south to southwest wind.
Today after 12z...VFR with sct-bkn aoa 5000 ft. South to southwest
wind gusting around 15 kt during the afternoon. Chance of a shower
or tstm but not in the TAFS till more convinced of nearby passage
of any convection. for now we have prob30 of a mdt afternoon shower
in KRDG and KABE.
Tonight...VFR. Any evening convection diminishes and end early and
think mostly north of our TAF sites. Light south to southwest wind.
Predominantly VFR during the day through the period, with MVFR
possible Sunday night thru Monday night.
No marine headlines through tonight.
Southerly flow persists...at times gusty to 15 or 20 kt. Seas generally
1-3 ft. More conservative NWPS wave heights were used for this 330AM
Winds and seas are expected to remain below SCA criteria during
the Saturday thru Tuesday time frame. Some maritime fog is possibe
RIP CURRENTS: Probably issuing low risk today. Again with warmer than
normal temperatures, that seems to be one part of the recipe for
heightened surf zone danger. Another part: unguarded beaches. The
water temperatures were still only in the lower 60s.