Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 220744
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
344 AM EDT SUN MAY 22 2016

.SYNOPSIS...
Low pressure well off the New Jersey coast this morning will
continue to track out to sea today. It will be followed by another
low Monday and Monday night. A ridge will build over our region for
Tuesday and Wednesday.  The ridge will remain to the east of the
area into the weekend while a few weak disturbances will affect the
Middle Atlantic region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
An upper air analysis placed a trough across the east with its axis
just to our west early this morning. Several short waves were
analyzed within this trough and will play the main role in our
weather for today. The forecast challenge is how much can the cloud
cover erode during the course of the day and also shower chances.
Lingering areas of rain early this morning continue to ease off to
the east and gradually weaken as an initial short wave departs.

The model guidance continues to highlight areas just to our west and
south with the best chance for shower activity during the course of
the day. This is due to the presence of the trough axis and lower
heights along with steepening mid level lapse rates. The main short
wave that will allow the trough to become closed off by late in the
day is forecast to track to our south. As this occurs, some drying
may try to work in from the north. This all spells for a tricky
forecast regarding the details as our western and southern zones may
be very close to the pop gradient. We used a model blend to try and
capture this a bit better, which results in the highest pops around
the edges of the CWA during the day. If enough breaks in the cloud
cover can develop then perhaps some low topped convection can occur.
This looks more of a chance to our west and south. Therefore we will
continue with no thunder mention.

As low pressure offshore continues to move farther away today, the
pressure gradient will continue to relax. This in combination with
the upper-level trough overhead should result in a decreasing wind
field through much of the column today. This may result in any
showers becoming slow movers with localized downpours possible.
Overall, today looks more showery as we transition from the more
stable and stratiform setup.

As for the high temperatures, we used a MOS blend overall. The
warmer temperatures are across the northern areas where a better
chance of some heating and developing drier conditions may occur.


&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
The persistent upper-level trough becomes more closed off as the
synoptic pattern is of an omega block. The closed off portion of
this trough is forecast to track to our south tonight. This should
take the bulk of the forcing with it with lingering showers across
the western and then the far southern areas waning during the
evening hours. We are still expecting a decent amount of cloud cover
although the ceilings may rise some from north to south. The extent
of any clearing though will determine if some fog can develop given
the moist ground and light winds. As of now, any fog that may form
overnight looks to be localized and therefore a mention was not
included at this time.

As for the low temperatures, we used mainly a MOS/continuity blend.
The temperatures may be slow to fall especially where cloud cover is
more notable for awhile.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...

The H5 heights across the east will be at their lowest at the
beginning of the long term with a cut-off low across the VA cape
region. The first sfc low from the near term will have moved off
into the Atlantic while a second low will be deepening well offshore
and moving northward well east of the area. The continuation of low
level moisture and cooler temps aloft will keep the area unsettled
with sct showers and afternoon tstms for mon and into tue. pops are
generally in the chc range. temperatures will be below normal Monday
and close to normal Tuesday. There will likely be more sunshine on
Tue with dryer air beginning to arrive across the area.

The Tue night thru Thu period will be mostly dry with sfc and upper
high pressure affecting the area. We have continued with a small chc
for an afternoon TSTM across the far n/w areas Thu afternoon.
Temperatures will be above normal thru the period with highs
reaching the low 80s in many areas Wed and then low and mid 80s for
Thu. Humidity levels will be mostly comfortable thru the
period...however a trend toward higher dew points will be under way.
It could be muggy across the Delmarva by Thu afternoon.

The mild temperatures will continue for the end of the ween and into
the weekend. Highs will mostly be in the 80s each day except across
the Srn. Poconos and along the shore. Chc for showers and Tstms
exist for both Fri and Sat...although the activity will be sct and
will be more of the typical summer-time variety.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Today: Areas of MVFR ceilings this morning should lift to VFR
ceilings this afternoon. Some IFR ceilings early this morning mostly
at KACY/KMIV are expected to improve through midday. Some showers
early this morning will send the local visibility into the MVFR
range, then mainly scattered showers are anticipated through the
afternoon with the best chance west and south of KPHL. Northerly
winds 5-10 knots, becoming light northwest to southwest this
afternoon and even light and variable.

Tonight...VFR ceilings overall. Some showers around mainly in the
evening can locally reduce the visibility for a time, then there is
a chance of local MVFR due to fog late. Winds mostly light and
variable.

Outlook...
Monday thru Tuesday...vfr or mvfr with sct showers/tstms mostly
   during the afternoons. fog possible mon night.
Tue night thru Thu...Mostly vfr. Sct tstms n/w thu afternoon. some
   fog possible during the overnight periods.

&&

.MARINE...
Low pressure will continue to move farther out to sea today,
allowing the pressure gradient to relax. The winds have already
diminished across much of the area already. As the wind diminishes
through the day the direction will become variable across the
waters. The seas however remain elevated across much of the Atlantic
coastal waters, however they continue to be slow in building passed
3 feet across the far north. We will continue the Small Craft
Advisory as is (through at least tonight) mainly for elevated seas.
The conditions are expected to remain below advisory criteria on
Delaware Bay through tonight.

RIP CURRENTS...There is a moderate risk of rip currents today.
Northerly winds will be less and also become variable this
afternoon, however a higher swell height into most beaches should
lead to an elevated risk for the formation of dangerous rip currents.

outlook...The last of the SCA conditions across the srn coastal
waters Monday. near SCA seas possible Tue across the ocean with
the second low out to sea. Mostly sub-sca Tue night-Thu.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ452>455.
     Small Craft Advisory until 6 AM EDT Monday for ANZ450-451.

&&

$$
Synopsis...O`Hara
Near Term...Gorse
Short Term...Gorse
Long Term...O`Hara
Aviation...Gorse/O`Hara
Marine...Gorse/O`Hara



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