Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 240049
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
849 PM EDT Mon Oct 23 2017

.SYNOPSIS...
A strong cold front will approach from the west today and slow,
finally moving completely offshore Tuesday afternoon. Showers
and thunderstorms are expected along and ahead of the front with
the possibility for a line of strong to severe thunderstorms
this evening and tonight. In the wake of the front, dry and
cool air is expected through Thursday as Canadian high pressure
takes hold. A warming trend begins Friday. Shower chances
increase Saturday as a weak area of low pressure develops ahead
of a second cold front.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 830 PM Monday...Axis of surface-based instability was
moving eastward across the Pee Dee region as of 00Z, with LI`s
of -2C to -3C extending from near LBT southward through
Kingstree. Modest surface pressure falls were occurring just
east of this axis of instability, and will transition eastward
and off the coast over the next few hours. Although backing of
the surface winds in response to these pressure falls has been
modest across the CWA, the shear profiles as evidenced by KLTX
VWP will remain conducive for storm rotation through the remainder
of the evening. Latest HRRR indicates the thunderstorm activity
will move off the coast around 06-07Z.

Cool advection lags considerably behind the wind-shift though
dewpoints may start dropping Tuesday afternoon temperatures will
still warm up into the upper 70s, a solid category above
climatology.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...Very quiet conditions will settle into
the area as a deep full latitude mid level trough moves from the
Tennessee Valley to just offshore through the period.
Precipitable waters dip to near one quarter of an inch by late
in the period. At the surface a somewhat blustery pressure
gradient will reside across the area and this is reflected n the
guidance. There may be some decoupling early Thursday morning
allowing temperatures to possibly drop to the coolest readings
of the season in some areas with lower to mid 40s area wide.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 PM Monday...Very cool temperatures start the extended as
Canadian high pressure settles across the area before pushing
offshore Friday. Temps Thursday will likely be about 5 degrees below
climo before recovering to more seasonable temps Friday as the
surface high shifts offshore. Moisture will begin to increase
Saturday on increasing southerly winds as a pre-frontal airmass
returns ahead of a deep mid-level trough pushing through the MS VLY.
This will drive a cold front across the area Saturday night into
Sunday. Ahead of this feature, a weak area of low pressure may
develop and move just off the coast, and while total column
moisture remains confined below 700mb, showers are possible late
Saturday through Sunday morning associated with this feature.
This front will bring the potential for the coldest air of the
season behind it, as 850mb progs drop below 0C and extended MOS
numbers feature values as much as 10 degrees below climo early
next week.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 23Z...Latest radar showing precipitation moving up the SC
coast soon to impact KMYR and KCRE. Light rain already at KFLO
and KLBT with nothing yet at KILM. Forecast for the overnight
period still a bit tricky with VAD wind profile showing some
veering between 8k and 17k with 35 to 45 kt winds. As front
pushes to the east storm motion is moving all cells to the NE at
greater than 30 mph. Impacts will affect all terminals through
the evening/overnight period with high confidence in MVFR and
possible IFR conditions in vsby and ceiling. Have mentioned tstm
across the inland terminals but not to confident at the coastal
terminals although cannot totally ruled out but will not
mention at terminals.

Gusty SSE to S winds will prevail overnight until FROPA and
will mention low ceilings and vsby across KLBT and KFLO with
fog as winds abate behind the front. Weather will improve from
west to east across the terminals. Concern might be for some
wind shear around 03z near the coast but will keep an eye on
this as VAD winds are pretty uniform with the wind speeds from
the sfc up to about 4-5K. main concern for all terminals will be
between 00Z and 06Z before condition slowly improve. After
25/15z VFR conditions across the region.

Extended Outlook... VFR Wednesday through Friday. Slight chance for
showers Saturday.

&&

.MARINE...
NEAR TERM /THROUGH TUESDAY/...
As of 830 PM Monday...Latest buoy obs are indicating strong
southerly winds across the waters, with gusts of 25-30 knots.
Seas at buoy 41013 were running near 8 feet. Latest guidance
suggests winds will diminish late tonight across the SC waters,
and early Tuesday morning north of Cape Fear. Seas will subside
below SCA thresholds beginning early Tuesday south of Little
River Inlet, and by early afternoon across the waters north of
Little River Inlet in the wake of the wind shift. Won`t make
changes to the SCA at this time, but if this timing expectation
holds, we may be able to remove the southern waters from the
SCA a little earlier on Tuesday than 18Z.

SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...Northwest winds of 10-15 knots and on
occasion 15-20 knots will prevail across the area through the
period. The persistence will be provided by a very deep and slow
mid level trough at 500mb that trudges across the conus from
the Mississippi Valley. Significant seas will be mostly 2-4 feet
with the higher values across the outer waters with the
offshore flow.

LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 300 PM Monday...High pressure moving overhead the waters
Thursday into Friday will create gusty north winds early
Thursday before weakening to less than 10 kts and shifting
slowly to NE Friday, and then E on Saturday. A secondary front
approaching very late Saturday may cause winds to uptick again
at the end of the period. The gusty north winds early will keep
seas elevated at 3-4 ft the first half of Thursday, before
falling back to 1-3 ft Fri and Sat. The increased winds late
Saturday may cause seas to begin to rise again at that time.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 2 PM EDT Tuesday for AMZ250-252-254-
     256.

&&

$$
SYNOPSIS...JDW
NEAR TERM...CRM
SHORT TERM...SHK
LONG TERM...JDW
AVIATION...MAC



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