Area NWS Forecast Discussion
000
FXUS62 KILM 061927
AFDILM
Area Forecast Discussion
National Weather Service Wilmington NC
327 PM EDT Sat Jun 6 2020
.SYNOPSIS...
Warm tropical moisture will fuel scattered showers and thunderstorms
this weekend. A cold front will drop slowly south through the
Carolinas late Sunday, stalling near or just south of area on
Monday. Limited showers on thunderstorms Monday and Tuesday will
increase through late week ahead of a front.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
A complex upper level pattern will sharpen further over the 36 hours
as a shortwave off the East Coast deepens the trough out there, and
Tropical Storm Cristobal lowers heights over the Gulf Coast. In
response, an upper ridge will almost become a cutoff feature across
the Ohio Valley on Sunday night. Our steering flow aloft will shift
from westerly to northwesterly between the narrow ridge and the
offshore trough.
Deep westerly wind aloft has developed a Piedmont Trough across the
interior Carolinas. This feature will work in concert with an cold
front approaching from the north to sustain a low level jet across
the eastern Carolinas tonight. Speeds at 1500 feet are expected to
increase to 30-35 kt. Down at the surface winds should die away to
10 mph tonight, but boundary layer turbulence should help hold low
temps in the lower to mid 70s for most areas. Convection so far
today has remained shallow across Bladen and Pender counties. The
window for any new convection should close before sunset with mainly
dry conditions expected overnight.
The cold front will make it into southeastern North Carolina by late
Sunday afternoon, easing down to near the state line shortly after
midnight. High res models are particularly insistent thunderstorms
will precede the front, and this makes sense given good convergence
and uncapped instability present along it. There is very little
support aloft, and a dry troposphere above 7000 feet AGL won`t help
matters either. I`m holding PoPs in the "chance" range (30-50
percent) across southeastern NC Sunday afternoon, spreading down
into northeastern SC Sunday night with 20-30 percent PoPs. There
won`t be a significant push of wind behind the front and dewpoints
will hardly budge even with light northeast winds expected to spread
in late.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Drier high pressure will reach in from the N to NE on Monday
into Tues, but lingering boundary and moisture could keep some
clouds and shwrs around, mainly across SC or inland NC. A ridge
in the mid to upper levels should help produce enough dry air
and subsidence aloft to limit convective growth, but a lingering
front could be the focus for afternoon shwrs on Monday
afternoon. Confidence is low as to exact location of the front
with areas north of the front in drier high pressure with below
normal temps in the lower to mid 80s, especially across NC. Any
convection will dissipate Monday evening with slightly below
temps for Mon night.
A deeper southerly flow will develop into Tues over the
Carolinas as remnants of Cristobal lift north up the
Mississippi Valley. The ridge will begin to get squeezed out
with increasing moisture in the upper levels, but enough
subsidence and dry air through the mid levels should help limit
convection or possibly may remain further inland. Clouds should
be on the rise though. Temps will be in the mid 80s most places
on Tues.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As remnants of Cristobal lift north through mid week, a deep
southerly flow of moisture will slide east into the Carolinas
ahead of deep trough and front. This plume of moisture with pcp
water values over 2 inches will pool ahead of the front and
should produce increasing clouds and chc of shwrs and
thunderstorms late Wed into Thurs before shifting offshore
Fri. Drier high pressure will build in briefly on Fri into Sat,
before digging trough pushes another front over the area over the
weekend, increasing convective activity once again. ECMWF is
slower with features and keeps more unsettled weather into Fri
with the dry day on Saturday. Temps look like they will remain
slightly below normal during the day and slightly above normal
at night with such increased moisture and clouds.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A weak trough may kick off some afternoon showers, otherwise VFR
conditions will prevail. Southwest winds will bring warm humid air
into the region. The HRRR model has isolated showers this afternoon,
mainly near the coast. Southwest flow continues tonight with little
or no fog expected.
Extended Outlook...A cold front passage will bring a slight
decrease in showers and thunderstorms into early next week, but
MVFR ceilings are possible in wake of the front.
&&
.MARINE...
High pressure is well offshore out beyond Bermuda. A Piedmont Trough
nearly stationary across the interior Carolinas plus a cold front
dipping south across the Mid-Atlantic states will both tighten up
the pressure gradient tonight, producing a period of 20-25 kt
southwesterly winds. Wind speeds are already increasing with today`s
seabreeze, but should continue to rise through the evening as a low-
level jet develops with 30-35 knot winds just 1500 feet up. Gusts
could approach 30 kt by late this evening, but will begin to die
away late tonight.
The cold front should continue to move south across North Carolina
during the day Sunday, reaching the Cape Fear area during the late
afternoon or early evening. A line of thunderstorms may accompany
the approach of the front. Southwest winds will shift northeasterly
behind the front Sunday night, but will little increase in wind
speed expected.
High pressure extends down from the north as it migrates
eastward to the north of waters through midweek. This will
produce a NE to E wind initially veering around to SE to S by
Wed into Thurs. Seas will mainly be 3 feet or less. A cold
front will approach on Thursday with increasing southerly winds
at 10 to 15 knots as early as Wednesday evening. Seas will
build to 3 to 4 feet in this southerly push.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Beach Hazards Statement until 8 PM EDT this evening for SCZ054-
056.
NC...Beach Hazards Statement until 8 PM EDT this evening for NCZ106-
108-110.
Coastal Flood Advisory from 9 PM this evening to 2 AM EDT
Sunday for NCZ107.
High Rip Current Risk until 8 PM EDT this evening for NCZ110.
MARINE...Small Craft Advisory until 7 AM EDT Sunday for AMZ250-252-254-
256.
&&
$$
SYNOPSIS...ILM
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
MARINE...TRA/RGZ