Area Forecast Discussion
Issued by NWS Wilmington, NC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS62 KILM 230700
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
300 AM EDT Wed May 23 2018

.SYNOPSIS...
A weak cold front approaching from the north will produce a
greater coverage of showers and thunderstorms today and on
Thursday. The front will dissipate by Friday. Low pressure
developing across the Gulf of Mexico will bring tropical
moisture northward and help fuel a higher probability of showers
and thunderstorms with heavy rain across the eastern Carolinas
Sunday and into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Wednesday...Expect an active day regarding showers and
thunderstorms as gradual height falls, a very moist column and a
cold front slipping south work in tandem. I am liking the guidance
trend of showing mostly sea breeze/air mass showers and isolated
thunder later this morning and early afternoon. More organized
activity appears to develop later in the afternoon from north to
south with the added assist from the front or more likely an outflow
boundary emanating from early convection to the north with the
front. We are still advertising likely pops from late morning on.
Regarding severe potential, plenty of CAPE but shear is a little
light. Flooding could pose a threat especially along the coast where
plenty of rain has fallen in the past few days and somewhat sluggish
storm motions. Activity could persist through the overnight hours,
but should trend downward somewhat. The MET guidance has been
spectacular with temperatures and opted for these numbers almost
verbatim.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 AM Wednesday...A weak cold front will be in close
proximity Thu and should become ill-defined to our S by Fri. An
area of high pressure will briefly nose into the area from the
N, moving progressively offshore late in the period. An upper
trough will lift out Thu followed by a building ridge Fri and
Fri night.

Precipitable water values will only drop very modestly as we
move from Thu into Fri with slightly more drying noted later Fri
and Fri night. Given a front will be slowly dissolving across
the area as it struggles to advance southward, it will be
difficult to refrain from including at least some risk for
showers and thunderstorms. Moisture profiles show the moisture
depth decreasing, especially later in the forecast period.

Will show chance to likely POPS Thu and this activity is expected
to lessen significantly or end with nightfall. Then on Fri, will
include mainly slight chance/small chance for convection, mainly
across South Carolina. Expect the convection Fri to be mainly
diurnally driven.

High temps will be near to slightly above normal for late May.
The beaches will be coolest as onshore flow prevents them from
rising above the upper 70s and lower 80s. Lows will be in the
mid 60s to lower 70s.


&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 PM Tuesday...A baggy upper level trough across the
lower Mississippi Valley and Gulf of Mexico will become better
defined Saturday and Sunday. Upper ridges building across the
Pacific coast of Mexico and out over the western Atlantic
between the Bahamas and Bermuda will help to spin this feature
up. A surge of Caribbean moisture very similar to what we saw
last weekend will be drawn northward in the deep southerly flow
between this upper trough and the offshore ridge, and this
could lead to another significant rainfall event Sunday into
Monday. The latest WPC QPF outlook for just Sunday and Monday is
around 1.5 inches across our area, with forecast 7-day totals
of 2-3 inches.

Latest models show there will probably be some sort of low
pressure development across the Gulf of Mexico late this week,
but FSU cyclone phase diagrams show only the Canadian
developing a significant warm core aloft. The 12z ECMWF (not
currently part of the FSU website) shows the cyclone keeping a
pronounced gradient in 1000-500 mb thickness above the surface
low, implying subtropical characteristics at best. The GFS is
the farthest east with its low pressure development across
Florida on Sunday, while other guidance is westward. While not
ruling out anything just yet, it`s expected the low will remain
too far west for any direct impacts on the Carolinas, but
enhanced southerly flow should help enhance our rainfall
potential Sunday and Monday when my highest rainfall chances
(50-70 percent) are currently forecast.

A warm day Saturday when there will be more sunshine and lower
shower chances. Highs should reach the mid to upper 80s inland,
several degrees cooler near the coast. Temperatures should top
out in the lower 80s Sunday, and lower to mid 80s Monday and
Tuesday. Lows in the upper 60s to lower 70s through the period
are evidence of the tropical airmass we`ll have in place.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 06Z...Local radar is mostly quiet this morning and is
expected to remain so until later in the day when heating
commences. Overall expect a similar morning to yesterday with
some tempo MVFR BR developing within overall VFR conditions.
Good coverage of showers and thunderstorms expected later today
but confidence is not quite high enough to warrant anything
other than VCTS. The 12 and certainly 18 Z package may have
just enough confidence on near term trends to better pinpoint.

Extended Outlook...The potential for MVFR/tempo IFR will
increase late Wed/Thur as a cold front drops across the area
and again during the weekend as tropical moisture returns.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Wednesday...Southwest winds of 10-15 knots will be
in place for most of the day across the waters. Some increase
in speeds to 15-20 knots is expected this evening with enhancement
of low level jetting especially across the southern waters. A
west to even northwest flow develops late tonight into early
Thursday morning as a front or arguably outflow pushes across
the waters. Significant seas remain in a 2-4 foot range.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 AM Wednesday...A weak cold front will be in close
proximity Thu and should become ill-defined to our S by Fri. An
area of high pressure will briefly nose into the area from the
N, moving progressively offshore late in the period.

The wind direction Thu will shift from W and NW early to easterly.
Easterly winds will then hold into Fri before veering to SE Fri
afternoon and S fri night. Wind speeds will be no higher than
around 10 kt through the period. Seas will be 2 to 3 ft. A SE
swell should gradually build across the waters late in the
period.

LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 300 PM Tuesday...Bermuda high pressure will remain well
off the Southeast coast this weekend. By itself it would provide
a gentle southerly wind and typical summertime weather. However
models over the past few days have been showing the potential
for a tropical or subtropical cyclone to develop across the Gulf
of Mexico by Saturday. The GFS is the farthest east of any of
the models with its latest run showing a low reaching Florida
on Sunday, while the ECMWF and Canadian are farther west. While
it`s too early to completely rule out impacts, our latest
forecast has south winds increasing to around 15 kt Sunday, with
a lengthening fetch of stronger winds extending down into the
Bahamas. This could build seas up toward 6 feet, assuming our
wind forecast is correct.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$

NEAR TERM...SHK
SHORT TERM...RJD
LONG TERM...TRA
AVIATION...SHK



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.