FXUS62 KILM 190807
Area Forecast Discussion
National Weather Service Wilmington NC
407 AM EDT Mon Mar 19 2018
A warm front will lift north across the area Monday, bringing
occasional showers. A series of developing surface lows will
bring wet conditions Monday night through Wednesday, with colder
and drier weather arriving Thursday. A wintry mix is possible
Wednesday followed by a frost or freeze each morning Thursday
and Friday. Temperatures will warm into next weekend as low
pressure approaches from the west.
.NEAR TERM /THROUGH TONIGHT/...
As of 3 AM Monday...Surface high weakly building in from the
northeast this morning quickly moves farther off the NC coast today.
Resulting onshore low level flow and mid-level southwest flow lead
to increasing moisture. The lowest layers will take the longest to
moisten up and precip has been slow to move into the area. Light
rain is just about to move into Georgetown and Williamsburg counties
but it will take a while to spread farther north. Most areas are not
likely to see any rain until after sunrise. Forcing is limited with
rain during the day being mainly driven by weak isentropic lift as
the front stalled to the south slowly returns north. Flow aloft
remains progressive with very little in the way of shortwave energy
passing overhead at any point during the forecast period. Warm front
is lifted north of the area by low pressure moving into the TN
Valley this evening and overnight. Secondary wave develops along the
front tonight, as it lifts across the area, which ends up shifting
the heavy rain north of the area. Cannot rule out thunder,
especially later today and overnight as the warm front draws near.
However soundings do not look supportive of widespread thunder.
Afternoon and evening convection will be elevated with minimal
connection to the surface layer. Passage of the warm front
significantly lowers the LFC but even then conditions are not such
that severe or even strong storms are a concern.
Cloud cover and east-northeast flow will keep highs a little below
climo with lower 60s expected. Warm front lifting across the area
this evening will result in temps holding steady then slowly
increasing from around midnight on. Lows will end up well above
climo with mid to upper 50s expected.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 300 PM Sunday...Front stalled south of the area as the
period begins will be lifted north across the area by
approaching low pressure Mon night. Pattern aloft is flat, with
the surface low being a reflection of a weak 5h shortwave. Lack
of amplification will help push the system west to east pretty
quickly. Isentropic lift coupled with upward motion associated
with the low/shortwave combo will likely lead to rain, with some
convective elements, continuing for much of Mon night. Forecast
area is solidly in the warm sector for a period of time Tue.
Mid-level drying in the morning suggests there might be some
peaks of sunshine possible, but extended clearing is unlikely.
Cold front moves into the area Tue afternoon, but does so from
the north. Should be enough CAPE to generate at least some
convection along the front, especially in the afternoon when mid
level moisture picks up. Thunder might be a reach though given
limited moisture above -10C, assuming forecast vertical profiles
are correct. Front continues to sink south Tue night with a
noticeable lack of drying. Forecast precipitable water does
trend down, but not significantly and this is mainly due to the
cooling of the air mass and not dry advection. Forecast
soundings suggest low cloud and light rain/drizzle will linger
into Wed morning.
Temperatures will run well above normal Mon night and Tue. Mon night
the arrival of the warm front will bring about an atypical temp
curve with lows bottoming out in the low to mid 50s close to
midnight. Could see a several degree temp rise between midnight and
daybreak Tue. Highs Tue will be in the low 70s with potential for
mid 70s should the sun peak out for any period of time around
midday. Cold advection in the wake of the front sets up Tue night
with temps dropping into the low 40s, a little below climo for mid
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 300 PM Sunday...Deep mid to upper trough will swing across
the Carolinas on Wed as sfc low lifts north and deepens off of
the Mid Atlantic coast. CAA on the back end of the low combined
with potent shortwave energy and lingering moisture will bring
some rain or possibly even some snow showers Wed eve before all
pcp comes to an end. Model soundings show a fairly deep layer of
moisture below freezing heading into Wed eve. Too soon to tell
for certain, but have added a little SW- Wed night. CAA begins
in force leading into Wed with 850 temps dropping below 0c Wed
aftn and dropping further through Thurs morning, down to -5c.
Temps will drop into the 30s most places with some frost or
freeze potential in spots, both early Thurs morning and early Fri
morning. Continued cool through Thurs and Fri as dry and cold
high pressure builds down into the Carolinas. Temps both Thurs
and Fri may not reach above 60. Low pressure system will brush
the Carolinas Fri night into Sat as it moves toward the Mid
Atlantic coast. This will produce increase in clouds and greater
chc of rain across the area late Fri into early Sat. Temps will
be back to seasonable by next weekend.
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
As of 06Z...VFR conditions continue this morning with a large
swath of high clouds moving across the area. Surface obs reveal
much lower clouds on the doorstep and during the next few hours
these should slowly spread north across the area. Light rain
will accompany the clouds with precipitation becoming more
showery in the afternoon as a slow moving warm front lifts into
the Carolinas. Widespread MVFR is likely at times today but have
low confidence in any IFR of significance. Warm front lifts
north of the area this evening into the overnight period,
accompanied by another round of showers. Better chance for IFR
ceilings late tonight, but confidence is low.
Extended outlook...Periods of MVFR/IFR CIGs Tuesday morning
NEAR TERM /THROUGH MONDAY/...
As of 3 AM Monday...High pressure moving farther off the NC coast
today will maintain easterly flow over the waters into the evening.
Weak gradient in place will persist through the day and speeds will
be generally 10 kt or less. Front stalled south of waters this
morning slowly moves north, crossing the waters this evening as a
warm front. Gradient becomes more defined following the passage of
the front, as low pressure starts to develop. Southerly flow
develops after midnight with speeds increasing to 15 to 20 kt as the
period ends. Seas 2 to 3 ft today will start to build overnight in
response to increasing southwest flow. Not unreasonable to expect 3
to 5 ft seas as the period ends.
SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...Southerly flow will increase early in the
period as low pressure helps lift a warm front across the area.
Tightening gradient and modest low level jet will push speeds
to almost 20 kt with potential for gusts in excess of 25 kt late
Mon night into Tue. Cold front will move north to south across
the waters Tue afternoon and evening. Cold surge develops Tue
night with potential for 20 to 25 kt sustained and gusts around
30 kt late in the period. Small Craft Advisory seems quite
likely as the period ends with first speeds and then seas
exceeding thresholds. Seas around 2 to 3 ft at the start of the
period will build a little Tue due to increasing southerly flow.
However, the big increase will be Tue night, once the northeast
surge ramps up.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
As of 300 PM Sunday...Low pressure will deepen as it moves off
to the N-NE on Wed. A strong off shore flow will develop behind
departing low as plenty of cold air flows down over the waters.
Gusty N to NW flow Wed into Wed night will reach up to 20 to 25
kts. The off shore component to the flow will keep greatest seas
off shore with seas subsiding from 5 to 7 ft early Wed down to
3 to 5 ft by Wed night. CAA through Wed night will keep winds up
through the night. Seas will diminish through Thurs into Fri as
a lighter northerly flow will persist as high pressure extends
down into the waters. By Fri night into early Sat, winds will
pickup out of the south as next system moves toward the Mid
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