Area Forecast Discussion
Issued by NWS Wilmington, NC-- Highlight Changed Discussion --
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FXUS62 KILM 171306
Area Forecast Discussion
National Weather Service Wilmington NC
906 AM EDT Mon Apr 17 2017
A cold front will drop south into the area tonight and linger
through Wednesday, bringing the risk for showers and
thunderstorms each day. The Bermuda High will expand west over
the region Thursday through Saturday. Low pressure moving across
the southern states late in the week may bring unsettled
conditions to the area for the start of next week.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 9 AM Monday...Analysis of morning sounding data and latest
high-res guidance confirms earlier forecast. Only modest
instability this afternoon means isolated showers at best this
afternoon. Chances low enough to keep out mention of pops for
the daylight hours. Previous discussion follows:
The mid level pattern has now transitioned into a mostly zonal
configuration with a poorly amplified trough moving across the
Ohio Valley. A decent southwest flow has developed at the
surface across the region in between high pressure in the
Atlantic and the front associated with the trough to the
northwest. The system will continue to make slow progress to the
southwest with clouds and pops arriving late tonight. Guidance
is consistent with the scenario which is to say a broken line of
showers and embedded thunder should cross the area late tonight
into Tuesday morning. We continue to advertise low chance
increasing to good chance by Tuesday morning. As for today,
expect another warm and breezy day under mostly sunny skies.
Highs will be in the lower to middle 80s with overnight lows
(which have warmed a little) in the lower to middle 60s.
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.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 300 AM Monday...Primary headline this period is an uptick
in rain chances as a frontal boundary drops across SE NC and NE
SC and stalls. By daybreak Tuesday a cold front will already be
working slowly southward with plenty column moisture through
H5. Low-level onshore ENE wind flow in the low-levels and
frontal convergence should help set off showers and a few TSTMS.
A few weak upper disturbances along and behind the front in WNW flow
aloft will provide slight upper support and pockets of divergence.
Post-frontal onshore flow will knock maximums down around 10 degrees
F Tuesday compared to today, with a little warming trend into
Wednesday as the maritime influence wanes due to a decrease in wind-
speed vectors off the Atlantic inshore SSTs. No severe weather
signatures are predominant in this front. With heating Wednesday a
shower or storm may pop near the boundary but column moisture will
lessen into Wednesday.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 300 PM Sunday...A warm front will be lifting north across
the area on Wednesday while mid level flow remains flat and
weak. This should favor at least scattered coverage of
convection and some of the deeper storms may lead to nuisance-
type flooding. Things then turn quieter and much warmer on
Thursday with no appreciable surface features and a weak ridge
axis poking up well to our west. A backdoor cold front may sneak
through later Friday leading to one last warm day but also a
return of rain chances. A cooler air wedge becomes well
established on Saturday. The front associated with the leading
edge of this airmass may see cyclogenesis Sunday as a deep upper
trough gets carved into the Ohio Valley.
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
As of 12Z...VFR condtions expected through 6Z. A weakly forced cold
front will drift south across the area late TONIGHT increasing
clouds and the chance for showers and thunderstorms AFT 6Z. However
the highest pops remain at end of this forecast period as do the
better chances of flight restrictions, though MVFR ceiling possible
Extended outlook...MVFR/IFR conditions possible in scattered
convection Tuesday through Wednesday. VFR Thursday and Friday.
-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/...
As of 9 AM Monday...Latest obs of SW winds at 10 to 15 kts and 2
to 3 ft seas fits in well with the current forecast. See no need
to change things so latest update continues forecast as before.
Previous discussion follows:
The coastal waters will remain in between high pressure to the
east and a slowly increasing pressure gradient from the
northwest associated with a cold front. This leads to a
southwest flow of 10-15 knots with slightly higher speeds than
were observed Sunday. Signifiant seas will be confined to 2-4
SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 300 AM Monday...The marine environment will get a little
messy Tuesday as NE and ENE winds behind a southward moving cold
front increase to 15-20 KT and roughens up the waters with
pitchy wind- wave energy. An exercise caution statement of brief
Advisory is not out of the question since gusts to 25 KT may
become frequent for a while on Tuesday. Marine showers and
isolated TSTMS will be in the mix Tuesday into Wednesday on the
waters as well although it appears non-severe at this time.
Wednesday an improved day as winds ease up significantly, but a
few showers or a TSTM remains possible near a stalled frontal
LONG TERM /THURSDAY THROUGH FRIDAY/...
As of 300 PM Sunday...Some variability/changeability in the
wind Wednesday as a warm front lifts north across the forecast
zones. A late day southern component will become established and
a few knots of wind speed will open up late in the day and into
Wednesday night. Southwesterly flow will then round out the
period as high pressure off Canadian maritimes extends ridge
axis all the way south towards Bahamas.
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