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Area forecast discussion 
National Weather Service Mount Holly New Jersey
938 am EDT sun Apr 26 2015

Synopsis...
low pressure along the North Carolina coast will move out to sea
today and merge into a large low pressure circulation near Nova
Scotia early this week. Low pressure along the Gulf Coast Tuesday
moves to the southeast United States coast Wednesday then
intensifies northeastward Thursday. It becomes a large circulation
Friday to the east of New England. Warmer high pressure spreads to
our south next weekend.

&&

Near term /until 6 PM this evening/...
for the 930 am update...the current forecast seems pretty much on
track so no big changes have been made to the forecast grids for
today. Ocean water temperatures are still in the 40s and there will be
somewhat of an onshore breeze today so maximum temperatures near the shore
were lowered a bit. Otherwise...maximum temperatures today should be 5 to 10
degree f warmer than yesterday...especially from phl southward where clouds are
clearing out and a mostly sunny afternoon is expected. Light northerly winds
will prevail in the relatively weak pressure gradient between the offshore
low and high pressure ridge over the MS valley.

Previous discussion below...
low pressure off the NC coast will continue to pull away to the
east while high pressure gradualy builds across the area. A dry
day is expected with varying amounts of clouds. There will still
be some clouds associated with the offshore low across the south
this morning and then it should become sunny there later. Some
daytime cumulus will develop across the region this afternoon. Winds
will be mostly north or NE at 5 to 10 miles per hour. High temperatures will be a few
degrees below normal...but mostly in the upper 50s or low 60s...so
overall quite pleasant.

&&

Short term /6 PM this evening through 6 am Monday/...
the fair weather will continue tonight. High pressure remain to the
west while an upper trough will approach from the north.
Overall...sky conditions will average partly cloudy. Temperatures
will be milder than this morning with lows in the upper 30s north
and low to middle 40s elsewhere. Winds will be light...mostly from the
northwest.

&&

Long term /Monday through Saturday/...
500 mb: colder than normal heights prevail here most of this
forecast period with a large cyclonic circulation in the western
Atlantic near Nova Scotia, dominating the flow here through Tuesday.
Then a potentially complex interaction between the northern and
southern streams may yield another closed low near Long Island by
Friday. Ridging follows next weekend.

Temperatures: calendar day averages around 5 degrees below normal
Monday, maybe a few degrees below normal Tuesday then near normal
Wednesday - Friday, with a definite warming trend to follow next
weekend!

The 12/25 naefs situational awareness table has nothing extreme for
our forecast area the next 6 days.

Hazards this 6 day period: fire weather is the most likely consideration
prior to next weekend.

Forecast basis: unless otherwise noted, a 50 50 blend 00z/26 GFS/NAM
MOS guidance Monday-Tuesday, 00z/26 mex MOS Tuesday night and
Wednesday, then the 0521z/26 wpc gridded elements of maximum/min temp,
12 hour pop, 6 hour dewpoint-sky-wind from Thursday through next
Saturday.



The dailies...

Monday...breezy with northwest gusting 20-30 miles per hour during the day,
diminishing at night. Considerable cloudiness during the day with
scattered instability showers, mainly the daylight hours.
Confidence: above average.

Tuesday...partly sunny day, probably clearing at night. North-northwest wind
gusting to 20 miles per hour during the day, diminishing at night. Confidence:
above average.

Wednesday...partly cloudy. Light west wind. Confidence: average
except below average on the small chance of showers mentioned in
the afternoon.

Thursday...considerable cloudiness with chance of a sprinkle or
shower as the western lobe of the the Atlantic trough rotates southeastward
overhead and tries to form a closed low. North to northeast wind
gusting to 20 miles per hour during the day, possibly higher coast. Confidence:
below average.

A caveat for Thursday...there is a chance that the interaction of
the northern and southern stream short waves may yet result in a
strong rainy gale for our coast Thursday.

Friday...partly cloudy to clear. Northwest wind gusting 20 to 25 miles per hour.
Confidence: above average.

Saturday...partly cloudy. Northwest wind. Confidence: above
average. 00z/26 GFS MOS guidance.

&&

Aviation /13z Sunday through Thursday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.

VFR conds expected today at all taf sites with mostly clear skies.
Light north-northeast winds are expected this morning...shifting to north-northwest this
afternoon. Somewhat gusty NE winds have been reported at phl this
morning...this seems to be a local effect and should diminish this
afternoon.

Previous discussion below...
good flying weather is expected across the region today and tonight.
A low pressure system is moving well south of the area while weak
high pressure remain across our area. Clouds associated with the low
will remain over the region before moving east. Clouds are of the
middle variety across the Delaware-Maryland-Virginia and southern New Jersey with high clouds father
north. Winds are mostly light northwest/west and they will turn NE after
sunrise. Later today...a continuation of VFR with daytime cumulus scattered
across the region. Winds mostly NE 5 to 10 knots. Tonight...VFR
(mostly clear) with northwest winds 5 to 10 knots.

Outlook...
Monday...mainly VFR ceilings with scattered showers, mainly daylight hours.
Northwest wind gusty 20-25 knots during the day diminishing at night.
Confidence: above average.

Tuesday...VFR scattered-broken at or above 5000 feet. North-northwest wind gusty 20 knots.
Confidence: above average.

Wednesday...VFR with scattered-broken at or above 5000 feet. Small chance of an
afternoon shower. Light west wind. Confidence: average.

Thursday...VFR ceilings with a chance of a shower, mainly daylight
hours. North-NE wind gusty 20 knots. Confidence: average. Uncertainty
exists regarding the potential of the developing ocean gale
coming closer to the coast than now generally expected.

&&

Marine...
not a bad day to be out on the waters. Winds and seas will be gentle
with weak high pressure across the waters. Winds will mostly NE
today and then turn more nwrly tonight. Winds speeds mostly under 10
knots. Seas on the ocean mostly around 2 feet today and tonight
and on the Bay 1 to 2 feet through the period. A few showers far S
before dawn today...then dry the rest of today and tonight.

Outlook...
Monday...Small Craft Advisory may be needed for the nearshore waters during the
afternoon and evening where it will be more unstable with northwest wind
gusts near 25 knots along the nearest mile of the coast but less wind
once away from The Dock. No Small Craft Advisory hazard yet. Confidence for a
nearshore Small Craft Advisory is above average but not yet categorical.

Tuesday through Wednesday...no marine headlines are anticipated. Northwest
wind Tuesday gust to 20 knots and then a light wind Wednesday.
Confidence: above average.

Thursday...a Small Craft Advisory appears likely, especially the
Atlantic waters where hazardous seas will probably exceed 5 feet
off New Jersey and 7 feet east of Delaware. There is a small chance of
gale force gusts and 13 feet seas. Confidence: below average due
to the uncertainty regarding the size, strength and track of the
northeastward moving coastal Carolina low.

&&

Fire weather...
dry fuels and minimum afternoon rh's of 25 to 35 percent may necessitate
statements for increased fire danger sometime between this
afternoon and Tuesday afternoon. Winds today and Tuesday will be
close to the needed criteria or just below. Rh's are marginal.

&&

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

&&

$$
Synopsis...drag
near term...amc/O'Hara
short term...O'Hara
long term...drag
aviation...amc/drag/O'Hara
marine...drag/O'Hara
fire weather...

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