Area Forecast Discussion
Issued by NWS Wilmington, NC
FXUS62 KILM 291426
Area Forecast Discussion
National Weather Service Wilmington NC
1026 AM EDT WED JUN 29 2016
A cold front will stall near the coast today. This front will
linger in the vicinity through the rest of the week maintaining
near normal temperatures and a chance for thunderstorms each day.
A slight warming trend is expected this weekend into early next
week, but thunderstorm chances will continue.
.NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM Wednesday...Fog has dissipated in most places
leaving an extensive fetch of mid level cloud cover essentially
bisecting the area on a northeast to southwest plane. Forecast
dilemma shifts to this area persisting through most of the day
thus limiting convection and making high temperatures problematic.
I have shifted cloud cover some as well as pops. Will wait another
hour or two (knowing a few breaks can make a dramatic difference)
before trimming highs in these areas. No other changes.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 415 AM Wednesday...The longwave upper pattern is now set
for this period, and will persist into the long term period. This
in regard to the upper trof which will affect basically the
eastern 1/3rd to 1/2 of the U.S. It`s trof axis will remain west
of the ILM CWA this period, thus any sfc cold front that drops
toward the FA will not be able to punch thru. The front will
basically become parallel with the upper flow and thus stall
oriented ne-sw, as is the case this Wednesday. Will stay closer
to the wetter GFS and European Models this period. The NAM remains
too dry which includes it`s low pop Mos Guidance.
Occasional embedded mid-level s/w trofs within the flow aloft
will affect the FA. The dynamics associated with these will
further aid convection with both initiation and an increase
to the thunderstorm strength. This will be the case for Thu, from
early morning thru midday, and again during Friday, from midday to
the evening. Sfc features to aid convection include the stalled
front draped across the Coastal Carolinas which will begin to
retrograde by the end of this period, outflows from previous
day/night activity, and finally the daily sea breeze. Again, all
of these will aid the initiation of convection as well as maintain
them with the various boundary collisions. POPs will be highest
during the time frame associated with the effects from the mid-
level s/w trof mentioned earlier.
Used a consensus of GFS and European max and min temps. Daily
maxes to run in the mid to upper 80s with some low 90s inland.
This is basically the norm for this time of the year. And daily
lows in the mid to upper 70s, about 5 to 10 degrees higher than
the norm. Basically, not much of a diurnal temperature range.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 AM Wednesday...Increasing temperatures and humidity
through the 4th of July holiday, but this will be accompanied by
unsettled weather. A stationary front/cold front north of the area
Saturday will waver across northern NC into Sunday as it remains
parallel to the mid-level flow beneath broad northeast troughing.
This boundary will slowly sag southward through Monday, and with
PWATS remaining AOA 2 inches, diurnal convection will become more
widespread each aftn. The strength and coverage of convection will
be determined by weak impulses moving overhead which are hard to
time this far out, but it appears Sun/Mon may have the best chances
for storms with heavy rainfall as the front sags into the area,
acting as a focus on which mid-level energy will aid in increasing
tstm coverage. WPC mentions heavy rain potential Sunday, and this
could be carried into Monday as well. Still too much uncertainty to
highlight that in the forecast or HWO. On Tuesday, this front may
get pushed out to sea as a stronger shortwave digs through the mean
trough, but its possible this doesn`t happen until Wednesday since
the front may initially get pulled back NW. Will maintain slightly
above climo POP and Temps through the period.
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...Fog will be a factor for the first hour or two, scattering
at all terminals by 14Z. Lots of old boundaries from yesterday`s
convection. Precipitable water is highest near the coast, so expect
convection will be most likely in this area. Not sure of the coverage
so will go with VCTS at this time. Winds will be light and mainly
northwest, becoming southeast along the coast with the resultant.
EXTENDED OUTLOOK...Mainly VFR. Possible brief MVFR/IFR from scattered
convection each day. Possible brief MVFR from fog or low ceilings
NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM Wednesday...Very modest west to northwest flow still
in place following convection early this morning. Seabreeze and
the waning influence of the convection will allow south to
southeast winds to gradually develop. Seas remain on track at 2-3
SHORT TERM /ThursDAY THROUGH FRIDAY NIGHT/...
As of 415 AM Wednesday...Basically a persistent forecast with S
to SW flow becoming dominant. The sfc high centered well offshore
will ridge back to the local waters during this period. The
stalled boundary early on this period draped along the immediate
coast will slowly retrograde back to the west this period, thus
allowing this ridging to sneak in. The sfc pg will be relaxed at
the start with a weak tightening later in this period. Speeds will
run 10 to occasionally 15 kt. Significant seas will start out 2 to
3 ft and slightly build to 2 to 4 ft. The 4 footers primarily off
Cape Fear. Dominant periods will run 8 to 9 seconds with 3 to 5
seconds near shore during the day from the extent of the sea
breeze circulation. Convection will be ongoing this period with
the strongest occurring during early to mid-day Thu and again Fri
afternoon and evening.
LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 300 AM Wednesday...Stalled cold front north of the waters
will sink slowly southward through the weekend, but not cross into
the area until beyond the extended. This leaves offshore high
pressure as the dominant feature, with SW return flow persisting
both Saturday and Sunday. As the front sags southward, the
gradient will pinch, so wind speeds will rise from 10-15 kts
Saturday, to around 15 kts or higher on Sunday. The wave spectrum
will consistently feature a 9 sec E/SE wave and a 5-6 sec S/SW
wave, producing seas of 2-3 ft Saturday, 3-4 ft on Sunday.