Area Forecast Discussion
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FXUS62 KILM 190519
Area Forecast Discussion
National Weather Service Wilmington NC
1219 AM EST Sun Feb 19 2017
An upper level disturbance may bring a few light showers
tonight. Warmer temperatures this weekend should last through
next week. Dry weather during the first part of next week may be
interrupted as low pressure passes to the south spreading some
clouds and possible showers into the Carolinas late next week.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 930 PM Saturday...Precip on radar has almost completely
dissipated over the past few hours. Where light rain was
reported in ASOS/AWOS observations, only trace amounts fell.
I`ll keep a small region of 20 PoPs in the forecast for late
tonight with the approach of a vort max, now moving eastward
across Georgia where some patchy light rain is breaking out near
Atlanta. I`ve also added a little patchy fog across the Pee Dee
region where light winds, clearing skies, and just enough
boundary layer moisture may coexist just before sunrise Sunday.
Discussion from 630 PM follows...
Upper level low pressure located over southern Kentucky will
weaken as it moves eastward tonight, ending up over Virginia by
daybreak Sunday. Moving downward through the atmosphere...the
low is still discernible at 700 mb but by the time you get to
850 mb there is very little perturbation left in the wind field.
Low-level baroclinicity is naturally maximized near the Gulf
Stream this time of year, and this is where surface low pressure
should develop late tonight.
Satellite and radar show a zone of clouds and light rain
extending across the central Carolinas. ASOS cloud bases are
generally 10kft where precip is falling. With surface dewpoints
in the 30s and 40s I can`t imagine precip rates are going to
become heavy enough for measurable amounts to occur. I`ve
removed PoPs for this evening, anticipating only non-measurable
sprinkles to fall across the Pee Dee region into Lumberton over
the next few hours.
What could turn out to be a slightly better potential for precip
will develop late tonight as a 500 mb vort max currently over
Mississippi moves east to the Carolina coast. Models show
steepening lapse rates aloft as this feature (and the broader
upper low) approach from the west. If low-level winds remain
backed enough to maintain a ribbon of moisture along the coast,
elevated convection could develop from bases around 6000-7000
feet AGL with tops in the 15000-20000 ft AGL range. I`ll keep a
20 PoP in the 08-11z timeframe along the coast for this
potential and will continue to monitor model trends to judge how
likely it is we need to keep this in the forecast.
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
As of 300 PM Saturday...Time-height cross sections indicate rapid
drying early Sunday as winds throughout the column shift quickly to
the northwest. The mid-levels will remain quite dry through the
period as a mid/upper ridge transitions from the central plains
states on Sunday to the eastern seaboard by late Monday night.
Mainly clear skies Sunday will start to become filtered by cirrus on
Monday and through Monday night, but the period will remain precip-
There will be some cool advection in the 1000-850 mb layer Sunday
behind the front as low pressure strengthens offshore, and this
should result in max temps a few degrees cooler than Saturday. As
heights rise on Monday, temperatures should bounce a few degrees,
though light onshore flow should keep them in check along the
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 300 PM Saturday...Medium range guidance continues to point to
a very warm and mostly dry scenario for the eastern Carolinas
through the period. Overall the mid level pattern is one of west
to east with the exception of a closed mid level system
trudging very far south through the Gulf of Mexico and out in
the Caribbean. This system will have little to no affect on the
region. Regarding surface features, high pressure to the north
will be the dominant player with a weak coastal trough
developing Wednesday and hanging around through Friday. This
prevents the forecast from being totally dry with low chance to
slight chance pops for these days. A more significant system
approaches from the west next weekend. For temperatures its
mostly highs in the 70s and lows in the 50s beyond a slightly
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 06Z...An upper vort will try to rotate through the area,
however the HRRR model keeps dissipating the precip as it tries to
enter the CWA. Will keep the current VCSH in place with only a
sprinkle possible. Will probably stay with a mid cloud ceiling at
most sites. Some MVFR fog is possible after 08Z, confidence mod/low.
Sunday, northwest flow on the backside of the surface low pressure,
EXTENDED OUTLOOK...VFR conditions are expected. Chance of
showers Wednesday and Thursday.
NEAR TERM /THROUGH TONIGHT/...
As of 930 PM Saturday...No significant changes are needed to
the forecast at this time. Discussion from 630 PM follows...
The 12z Canadian appears to be the winner with wind speeds this
afternoon and this evening. Most of the other model guidance
was several knots too weak versus observations from buoys,
piers, and coastal airports. As weak low pressure develops off
the coast tonight southwesterly winds should veer west, then
northwesterly late. Seas are generally around 2 feet, although
there is some potential for an area of 3 foot seas to develop
south of Cape Fear this evening due to the 15 knot southwest
winds that have been blowing across Long Bay for the past
SHORT TERM/SUNDAY THROUGH MONDAY NIGHT/...
As of 300 PM Saturday...Offshore flow Sunday will veer to the
northeast Monday as a large area of high pressure extends southward
across the Mid-Atlantic. Although low pressure will develop well off
the SC coast Sunday, it will progress eastward rather quickly and
the gradient winds across the coastal waters are expected to remain
15 knots or less through the period.
LONG TERM /TUESDAY THROUGH THURSDAY/...
As of 300 PM Saturday...Expect northeast winds Tuesday on the order of
10-15 knots. By Wednesday the gradient weakens considerably with
more of an east to southeast flow developing. The sea breeze will
become more of a factor both Wednesday and Thursday. The weak
gradient will only produce wind speeds of ten knots or less.
Significant seas quite unimpressive through the period as would be
expected with the light wind fields with 2-4 feet Tuesday followed
by 1-3 feet Wednesday and Thursday.