Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Mount Holly New Jersey
835 am EDT Wednesday may 6 2015

Synopsis...
a cold front will slowly move through our region today as high
pressure settles into the area from the north and east on Thursday
through the weekend. Another slow moving cold front will approach
our area early next week...and move through the region by middle week.

&&

Near term /until 6 PM this evening/...
820 am early estf: the somewhat diffuse but still significant
cool front at 12z from northern Maryland through northern Delaware into S New Jersey
may settle a little more to the southwest today, especially Delaware
where sea breezes develop. 12z radar reality and a preponderance
of multi model guidance forecast showers across much of the region
from near Interstate 78 north.

Probability of precipitation were just raised 20-30 percent for showers northern half of the
forecast area. This probably associated with weak warm air advection near 850 mb.

Thunderstorms this morning vicinity kcxy should die out as they try to enter
the kcxy area.

This afternoon...the showers should diminish north and then we watch
for heavier convection to develop North Maryland and possibly leak into md's
East Shore late in the day.

&&

Short term /6 PM this evening through 6 am Thursday/...
ridge continues to build closer, and with the loss of diurnal
instability, any lingering showers should quickly dissipate.
Previous model runs had shown a weak short wave moving over the
region tonight. However, latest model runs show it much less defined
and really not much of a factor for our region.

&&

Long term /Thursday through Tuesday/...
middle-level pattern features a rexy looking block through the first
half of the longterm period, with split flow being the main player.
Closed low over the southeast coast will begin to lift/open up over
the weekend and the split flow breaks down by early next week.
Confluent flow with multiple waves of energy will affect the region
for the remainder of the longterm...Monday Onward.

Thursday and Friday...have gone dry both days with the offshore
ridge's axis across the region and the lack of a defined lifting
mechanism. Light south-southeast flow will keep low-level moisture
streaming into the region, though not a significant increase but
dewpoints climb into the middle to upper-50s. Temperatures will remain
above normal with Friday being the warmer of the two days...low-80s.

Saturday - Sunday...even with a decent surface and middle-level ridging
around the region, the slow northward advancement of the coastal/sub-
tropical low off the Carolina coast gives some pause for concern
with possible showers spreading northward into our southern zones
both days. Have introduced some slight to low-end chance probability of precipitation this
weekend. Light upslope flow across our western zones may allow for
an enhancement/convergence along the ridges for better chances of
showers/convection on Saturday. The flow veers towards the southwest
on Sunday with another increase in moisture and temperatures. Once
again have pegged our western zones, with the differential heating
and moisture pooling along the ridges for chances of convection.
Have also introduced some patchy fog/stratus along the eastern zones
each morning with the light onshore flow and damp marine layer.
Temperatures each day expected to be in the low-80s.

Monday and Tuesday...as a cool front approaches...there will be
greater moisture, lift, and instability available. Given a slow
frontal passage with ample Gulf/subtropical moisture, and favorable
jet dynamics...heavy rainfall is possible during this time frame.

&&

Aviation /12z Wednesday through Sunday/...
the following discussion is for kphl, kpne, kttn, kabe,
krdg, kilg, kmiv, kacy and surrounding areas.

Today...VFR ceilings with brief MVFR conds in showers vicinity kabe/krdg/kttn.
Light NE wind.

Tonight...VFR ceilings. Light mostly NE wind.

Outlook...

Thursday - Friday...VFR. Light south-southeast winds expected.

Saturday - Sunday...mostly VFR. Some early morning fog/stratus
possible around our eastern most terminals. Southeast flow giving
way to southwest winds on Sunday. Possible afternoon showers/thunder
each afternoon...better chances across the western terminals.

&&

Marine...
winds and seas should remain below Small Craft Advisory criteria today and tonight.
Winds should gradually shift to be out of the northeast through the
day, but wind gusts will remain less than 20 knots.

Outlook...

Thursday - Sunday...generally a sub-Small Craft Advisory forecast with seas
increasing a bit under a persistent southeasterly flow through
Saturday.

&&

Phi watches/warnings/advisories...
PA...none.
New Jersey...none.
Delaware...none.
Maryland...none.
Marine...none.

&&

$$
Synopsis...franck
near term...drag/Johnson 836
short term...Johnson
long term...Heavener
aviation...drag/Heavener/Johnson 836
marine...drag/Heavener/Johnson 836

National Weather Service Glossary of Abbreviations