Area Forecast Discussion
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FXUS62 KILM 200509
Area Forecast Discussion
National Weather Service Wilmington NC
1209 AM EST Fri Jan 20 2017
Weak high pressure will move offshore tonight. A series of mid
level systems will bring unsettled conditions Friday through
Monday. The strongest system will move across Sunday and into
early Monday. High pressure will build back in toward the middle
of next week. A weak cold front will move into the southeast and
stall in the region on Thursday.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 930 PM Thursday...Cloud cover continues to thicken as a
warm front advances from the south. Forecast in good shape with
no changes needed. Previous discussion follows:
Copious moisture streaming NE out of the GOMEX will start to
impinge upon the area through the period. Initially this will
take the form of cirrus/cirrostratus clouds but the overnight
period will introduce some mid and low level moisture as a warm
front approaches from the south. The mid level ridging will
shunt most of the precipiation north and west of the area.
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
As of 300 PM Thursday...Warm front lifting to the north on
Friday and mid level ridging should allow for waning rain
chances as the day wears on. Although cloud cover will decrease
slightly it will still be a mostly cloudy afternoon. Despite
this most locales should warm to 70 or better. Similarly the
clouds will help bring a very mild Friday night with low
temperatures just a few degrees shy of seasonable highs. Late
Friday night into Saturday the mid level ridging moves offshore
while another slug of mositure lifts out of the Gulf of Mexico.
Rain chances will increase as the day wears on. Overall amounts
may be rather limited however as the flattening ridge does hold
on just enough to shunt most of the shortwaves north and west of
the local area. This will hold less true heading into Saturday
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 300 PM Thursday...Uncertainty remains higher than normal
with respect to the system affecting the southeast Sun and Mon.
Period beings with warm front north of the forecast area and
what is likely to be convection ongoing across the region.
Initially coverage may be limited but as instability increases
Sun coverage will try to increase. The biggest limiting factor
during the day is likely to be mid level dry air which may or
may not be present. If there is an abundance of dry air Sun
afternoon, convection may end up rather isolated. However
anything that does develop would have the potential to produce
damaging wind gusts given low level jet of 40 to 50 kt.
Another round of unsettled conditions is expected Sun night and
early Mon as the stacked low moves from the southern Mississippi
Valley into the southeast. Severe weather is expected ahead of the
cold front, but the biggest unanswered question is where. Latest
GFS/ECMWF keep the bulk of the low level instability south of the
forecast area. Favored area for severe weather will depend on
location of occlusion/triple point low and is something guidance
continues to struggle with. Worst case, as far as severe threat
goes, would be a high shear/low cape event Sun evening/night but
confidence in this is rather low. 5h low moves overhead Mon which
would tend to generate some diurnal convection Mon afternoon but
potential for strong to severe storms Mon would be very low.
Storm exits northeast Mon night as weak surface and mid level ridge
move in from the west. In coming airmass has origins in the west
with very little cold air to speak of. Ridging aloft helps ensure a
couple dry days Tue/Wed as mid level subsidence prevents any upward
motion. During the middle of next week another stacked low will move
northeast from the plains through the Great Lakes and into
southeastern Canada. A cold front trailing the low will move into
the region before stalling as it ends up laying parallel to the flow
aloft. Increasing deep moisture in the presence of the front and
weak dynamics may generate a few light showers later Thu and Thu
night. Temperatures will be above to well above climo through the
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 06Z...Clouds lowering and thickening from the W and the S.
Expect MVFR ceilings to fill in through 12z throughout with perhaps
some sct IFR bases across KFLO and KLBT around daybreak and into the
morning hours as some light showers reach the area. These
showers may briefly drop visibility to MVFR inland, but
prevailing VFR visibility is expected to continue. MVFR ceilings
are forecast to hang on through the TAF period inland. At
KMYR/KCRE and KILM, ceilings should lift to VFR. Expect
widespread stratus and fog to develop tonight at all the TAF
sites with a frontal boundary lingering in the area. A look at
model soundings support IFR or lower conditions first at KCRE
and KMYR and so have introduced there 03/04z.
Extended outlook...IFR/LIFR likely developing Fri night and
continuing into Sat morning. Tempo MVFR or lower ceilings and
visibility expected in showers and thunderstorms Sat afternoon
through Sun night. Weekend convection will have the potential
for strong to severe wind gusts.
NEAR TERM /THROUGH TONIGHT/...
As of 930 PM Thursday...Latest obs show very light winds with
seas of only around 2 ft. That should be the rule for the
remainder of the overnight period. Previous discussion follows:
A poorly defined gradient will bring minimal conditions
overnight. Additionally any swell energy will remain well
offshore and also be shadowed locally by Cape Hatteras. The end
result will be light NE winds and waves no larger than 2 ft.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 PM Thursday...A south to southwesterly flow will
become established on Friday as a warm front lifts northward
across the area. With wind speeds capped at 10 kt or so through
the veering seas will remain no larger than 2 ft. Southwesterly
flow continues to be light into Saturday but may start taking up
more space across the western Atlantic. Wave periods may
increase slightly as a result.
LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 300 PM Thursday...Storm system affecting the region Sun
and Mon will create hazardous conditions across the near shore
waters for much of the period. Southerly winds will approach 25
kt at times Sun and Mon with gusts near gale force. The
prolonged period of south to south winds exceeding 20 kt will
build seas well over 6 ft with potential for double digit seas
in favored locations. Storm exits northeast during Mon and by
evening southwest flow will be west or even northwest. Gradient
is slow to relax and winds will remain near 20 kt through Mon
night and the first part of Tue. High pressure building in from
the west Tue afternoon will bring about a reduction in offshore
flow with speeds dropping below 15 kt by early evening. Offshore
flow will lead to a gradual reduction in seas with waves
dropping below 6 ft Tue morning and down to 1 to 3 ft by the end
of the period.