Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 291106
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
706 AM EDT Wed Mar 29 2017

.SYNOPSIS...
Relatively cooler and drier high pressure will build in from
the north beginning today. Showers and thunderstorms are
expected on Friday as warmer and more humid air returns ahead
of an approaching cold front. The cold front will sweep offshore
late Friday night. Some of the thunderstorms may be strong to
severe Friday. The weekend should be dry as high pressure takes
hold. Then early next week, a southern stream system will again
bring the risk for showers and thunderstorms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Wednesday...A cold front is slowly making its way
through the area this morning. There has been some patchy fog
but overall the drier air seems to be keeping significant
development at bay. A weak pressure pattern will become better
defined as the potent storm system crawling through the Central
U.S. pushes high pressure down the east coast. With some very
modest cold air advection there should be some convective
cloudiness mostly across northern areas. Some mid level clouds
may move across the area tonight from a glancing system to the
south. Guidance is in good agreement on daytime highs a little
lower than Tuesday with middle 70s eastern areas, where there
will be more clouds and possibly 80s again inland. Thursday
morning lows will be in the lower to middle 50s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 AM Wednesday...A strong area of high pressure centered
across eastern Canada at the start of the period and ridging
south across the Carolinas will drift E with the ridge axis
moving offshore during Thu. Low pressure across the Missouri
Valley Thu will move ENE across the Mid-West, ending up
offshore of the Mid-Atlantic states late Fri night. Its
accompanying warm front should reach the eastern Carolinas
late Thu night and then move to our N on Fri. A cold frontal
passage is expected later Fri night.

Still looks like a wet period beginning late Thu night and on
Fri with widespread showers and thunderstorms developing and
then coming to an end with the passage of a cold front late in
period.

The combination of upper level support and strong and deep moisture
return and lift should bring widespread half inch to one inch
rainfall amounts with amounts in excess of one and a half inches
possible.

There is a risk for strong to severe thunderstorms during this
time. 0-6 km effective bulk shear parameters have become more
conducive for severe weather. Instability does grow with mixed
layer CAPE values on the order of 500 to 1000 J/kg. These CAPE
values are certainly conservative when we talk about severe
weather in the Carolinas this time of year. The instability may be
somewhat limited given that rainfall is expected to develop Thu
night as isentropic upglide increases sharply ahead of warm
front. Clouds and rainfall should help to mitigate the
instability, especially early on, but a period of dry slotting
may allow clouds to thin during Fri which could support greater
instability and increase the severe risk.

Highs on Thu will be in the upper 60s to lower 70s with sunshine
giving way to increasing clouds Thu afternoon. Lows Thu night
will be in the upper 50s to lower 60s with temps having a tendency
to rise overnight. Highs on Fri will be in the mid and upper 70s.
Any signifiant breaks in the clouds will allow temps to surge
into the lower 80s Fri afternoon. Lows late Fri night will drop
into the mid and upper 50s with around 60 at the beaches.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 AM Wednesday...In the wake of this system, dry weather
and above normal temps are expected for the weekend as mid-
level ridging builds across the area and surface high pressure
to our N ridges S. Attention then will turn westward as next
potent southern stream system along the Gulf Coast Sun night
lifts to the NE and drags a warm front to the N. This will again
bring deep moisture into the Carolinas, and with that, showers
and thunderstorms early next week. Timing differences have
decreased slightly and it looks like the greatest risk for
showers and thunderstorms will be Mon night. Showers and
thunderstorms should be increasing from the SW and W Mon
afternoon with the risk decreasing from W to E during the day
Tue as broad low pressure consolidates offshore of the Mid-
Atlantic states Tue and Tue night. Drier air will work into the
eastern Carolinas during Wed.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
As of 12Z...VFR conditions expected through the valid TAF period.

Few to scattered stratocumulus will persist at the terminals and
may briefly become broken as a push of colder air noses in from
the NE this afternoon and tonight. The lowest of these clouds
will develop around 3500-4000 ft. Could be some patchy fog/
stratus late tonight and at this time will include mention of
stratus at KFLO with a scattered deck around 1 kft.

Extended outlook...Flight category restrictions are probable in
showers and thunderstorms late Thu night through Fri eve.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Wednesday...Currently there is a west to southwest modest
flow across the waters. A front will continue to push south over the
next few hours leading to a northerly flow. Speeds will remain
modest along the lower end of a 10-15 knot range. A stronger
northeast surge will develop later today with winds increasing to 15-
20 knots where they will remain through tonight. Once again leaning
toward the lower end of the range. Regarding seas, some lingering
five footers will abate later this morning with 2-4 feet ensuing.
Later tonight some five footers will once again develop across the
outer waters.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 AM Wednesday...A Small Craft Advisory is expected
for all waters late Thu night and into Fri night.

A strong area of high pressure centered across eastern Canada at
the start of the period and ridging south across the Carolina
waters will drift E with the ridge axis moving offshore Thu.
Low pressure across the Missouri Valley Thu will move ENE
across the Mid-West, ending up offshore of the Mid- Atlantic
states late Fri night. Its accompanying warm front should reach
the Carolina waters late Thu night and then move N of the waters
on Fri. A cold frontal passage is expected later Fri night.

Significant shower and thunderstorm activity is expected to
develop Thu night and continue through Fri before ending Fri
night.

The wind direction at the start of the period will be NE. Winds
will veer to easterly Thu afternoon, SE Thu night and S and SW
on Fri. SW winds Fri night will shift to NW toward Sat morning.
The strongest winds will occur Fri into Fri night, 20 to 25 kt,
increasing Thu night and decreasing later Fri night.

The highest seas, 5 to 7 ft and up to about 8 ft near Frying Pan
Shoals, are expected later Fri into Fri night. Seas will be
building Thu night and subsiding later Fri night.

LONG TERM /SATURDAY THROUGH MONDAY/...
As of 300 AM Wednesday...Small Craft Advisory conditions
possible late on Mon and Mon night.

Low pressure will be intensifying south of New England Sat
morning. Its attending cold front will be offshore by the start
of this forecast period. Low pressure will continue to intensify
as it moves E and then NE during the weekend. High pressure
centered across eastern Canada will build south across the
Carolina waters during the weekend with the ridge axis moving
offshore Sun night. Next in series of potent southern stream
systems will be approaching from the W on Mon. Its attending
warm front is expected to move across the waters Mon night.

NW winds will generally dominate Sat although an inverted
trough poking N may cause winds to back, especially across
southern waters ahead of reinforcing cold and dry push. Winds
late Sat night and Sun in the wake of this push will be NE. The
wind direction will veer to E later Sun afternoon and then ESE
Sun night. The wind direction will become SE during Mon.

The highest wind speeds during this period are expected on Mon
when they are expected to increase to 20 to 25 kt late day and
Mon night. Wind speeds Sat through Sun night should be mainly 5
to 15 kt.

Seas will be 3 to 4 ft Sat morning, subsiding to mainly 2 to 3
ft Sat night and then 1 to 2 ft Sun. There will be a tendency
for backswell to slow the slow the rate of subsiding seas
through the first part of the weekend. Expect seas will reverse
higher late Sun night and Mon, possibly reaching Small Craft
Advisory levels Mon night.

&&

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

&&

$$

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


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