Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 220721

Area Forecast Discussion
National Weather Service Wilmington NC
321 AM EDT Sun Oct 22 2017

Warm and dry weather is expected today, as high pressure moves
off to the northeast ahead of an approaching cold front. The
front will bring showers and a few storms late Monday through
Tuesday morning, and some storms could be strong. Cooler air
will spread across the region through mid-week, as the front
moves off the coast.


As of 321 AM Sunday...Temps and dewpoints have surged across
the forecast area over the last 24 hours in return flow around
surface high pressure. In general, most locations are 3-5
degrees higher than this time yesterday, however along the
immediate coast of northeast SC, onshore flow has yielded temps
and dewpoints as much as 8-10 degrees higher. Despite the
increase in low-level moisture, winds just off the surface are
slightly higher, and have not allowed patchy, dense fog to
develop to the same extent as the previous couple of nights.

The relatively high amplitude mid-level ridge axis will linger
off the eastern seaboard today and high temps will surge into
the low 80s, except for upper 70s at the beaches. The
combination of surging dewpoints and some unstable air may allow
a few showers to pop up by late afternoon across Georgetown and
Williamsburg counties, and if so, potentially affect portions
of the Pee Dee region overnight as they advect inland. Lows
tonight will remain on the order of 10-12 degrees above normal.


As of 321 AM Sunday...The chief caption this forecast period is
`wet and unsettled`, as a vigorous low pressure system brings
strong warm air advection and a dampening, but negatively tilted
upper trough through Monday night. This will generate strong
low level winds, in excess of 50 kt below 850 mb, and the SPC
has painted a `marginal` risk here. An axis of enhanced 0-1 km
helicity will move NE across the forecast area several hours
either side of 6z Tuesday. This period could see a tornado watch

Mid-level drying in wake of the frontal system will curtail
rainfall by midday Tuesday. Latest QPF consensus suggests up to
an inch of rain on average is expected. This seems plausible
looking at the rich plume of tropical moisture over the eastern
Gulf of Mexico poised to be drawn northward. Tuesday will remain
mild in wake of the frontal band, before the onset of cold air
advection Tuesday night. Lows Wednesday at daybreak upper 40s
inland to mid 50s coast, much closer in line with climatology.


As of 220 PM Saturday...Other than Saturday, remainder of the
Long Term looks to be dry as high pressure moves east across the
eastern Carolinas. Showers moving in advance of the next cold
front may impact the area on Saturday, but model solutions are
quite divergent so will keep pops on the low side. Temperatures
will drop to normal for late October on Tuesday in the wake of
FROPA, then even cooler for Wednesday and Thursday before a
warming trend commences for the end of the week.


As of 05Z...Winds have decoupled with the exception of KCRE and
KMYR. This may lead to a brief period of MVFR visibilities in
the predawn hours. Otherwise VFR expected through the period.

Extended Outlook...Showers and thunderstorms may result in flight
restrictions Mon-Tue.


As of 321 AM Sunday...The center of surface high pressure will
lift northeast from the Mid-Atlantic coastal waters today.
This, in combination with a frontal boundary making its way
across the Mississippi River valley, will produce onshore flow
and a slowly strengthening pressure gradient across the waters
through tonight. Sustained wind speeds will increase towards 15
knots over the northeast SC coastal waters by this evening, and
these speeds should be realized north of Cape Fear by the
predawn hours Monday morning. May also see some showers develop
off the northeast SC coast this afternoon and overnight as a
result of wind speed convergence and weak instability.

As of 321 AM Sunday...An increasingly dangerous marine period
upcoming as a strong frontal system approaches and crosses the
coast late Monday night through Tuesday morning. Ahead of the
front Monday night and early Tuesday, 30 KT S wind gusts will be
common, as seas offshore build to 5-8 feet by daybreak Tuesday.
Additionally, a broken line of TSTMS or squall, may be severe
early Tuesday morning moving farther seaward. Wind and seas will
become markedly higher in and near TSTMS, since low-level winds
in the atmosphere will be strong and capable of being mixed to
the sea surface. The storms early Tuesday will be capable of
localized gusts to 55 KT. Mariners are encouraged to obtain
radar updates to avoid a possible squall passage.

As of 220 PM Saturday...A strong cold front will be in the
process of moving across the waters near the beginning of the
period and should be well east of the forecast area by Tuesday
night. Expect steadily improving conditions through mid- week.





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