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Office: ILM

FXUS62 KILM 140052
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
752 PM EST Wed Dec 13 2017

.SYNOPSIS...
Temperatures will return to normal Thursday and Friday as a
pool of cold air aloft moves away to the northeast. Another cold
front will reinforce dry and cool weather this weekend. Low
pressure approaching from the Gulf will bring an increasing
chance of rain, and a warming trend through early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 8 PM Wednesday...Temperatures appear to have stabilized
and are even rising a bit over our western counties as warm
advection in advance of the next front takes hold. Dewpoints are
making an even more robust recovery and are now in the 20s and
lower 30s. This is all according to plan and have not needed to
make any major changes to the forecast. Previous discussion from
this afternoon follows:

Single digit dew point values are certainly a rarity in this
part of the world, but the 'Carolina Desert' appears to be in
place today with widespread dewpoints of 8-12F and RH below 30
percent. This certainly is an indicator of the dryness of the
airmass, echoed further by examination of the WV imagery, and
RAP soundings depicting PWATs around 0.25 inches. Temps have
rebounded better than forecast, approaching 50 in many spots
thanks to full sunshine, but temps will drop quickly after
sunset thanks to good radiational cooling in the dry column.

However, the temp and wind forecast tonight is less than clear-cut.
Warm advection will begin in earnest this evening as high pressure
ridges northeast from the Gulf Coast, and a clipper-type low
pressure moves through the Great Lakes creating a brief warm sector
across the Carolinas. While this regime will be short lived, it will
be quite strong, with 850mb winds forecast to exceed 40 kts, driving
surface winds through the overnight. Still expect a surface
inversion to develop, especially early, which will at least limit
gust potential overnight, but do forecast an increase in winds after
midnight and towards Thursday morning, with speeds of 10-15 mph
likely. If the inversion doesn't materialize, it could be a very
windy night, but at this time think there will be enough of a lag in
the LLJ development after sunset to permit an inversion first. As
winds pick up, temps will likely level off or increase the latter
half of the night, so mins in the low to mid 30s are expected early.

On Thursday, the aforementioned clipper will swing across the Mid-
Atlantic and drive a weak cold front into the Carolinas. Ahead of
this feature, temps will climb to seasonable norms in the upper 50s
to around 60, with continued nearly cloudless sky conditions in deep
westerly flow. The surface front, which has little to no temp
gradient across it, will swing across the region late in the period
with a wind shift to the NW at the surface but little other
fanfare.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 330 PM Wednesday...The deep east coast trough that has
been in place for some time now will relax a bit during the
short term period but not abate completely. A very broad trough
will develop out west and sink down into the area by Saturday
morning with an essentially dry frontal zone at the surface.
After a brief period of weak warm air advection Friday 850mb
temperatures will dip once again to near freezing or below by
Saturday morning. This will lead to surface temperatures at or
near freezing for most of the area for lows.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 330 PM Wednesday...The primary caption for the extended
period, 'Seasonably Cool and Dry This Weekend, Milder and
Wetter early Next Week'. In wake of a dry cold frontal passage
late Friday, a mainly fair and seasonably cool weekend appears
to be shaping up, before the onset of a warming trend into early
next week, as ridging aloft ensues. GFS and ECMWF differ on
timing and strength of ejected Baja short-wave Sunday, but both
agree on a milder and wetter pattern after the weekend. The
first chance of rain by Sunday night, as this features ejects
offshore early Monday. Despite ECMWF/GFS differences even into
Tuesday, it seems we can infer a mild pattern prevailing and
rain chances ahead of an upper trough, that in both models
appears along the east coast next Wednesday.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
aS OF 00z...Quite an airmass turnaround through the overnight hours
with dewpoints rising as much as 30 degrees. A southwest low level
jet sets up and should break the inversion sometime around midnight
with winds increasing and becoming gusty. Temperatures may rise 5 to
10 degrees. Thursday, VFR with more of a westerly wind as clipper
moves through the Great Lakes.

Extended Outlook...VFR.

&&

.MARINE...
NEAR TERM /THROUGH THURSDAY/...
As of 8 PM Wednesday...Advisory conditions have not yet
developed but winds are now increasing from the SW at 10 to 15
kts and seas are up around 2 to 3 ft. Still expect conditions
to deteriorate overnight as SW winds increase in advance of the
next front. No major changes with the latest update. Previous
discussion from this afternoon follows:

Westerly winds across the waters will transition to SW this
evening as WAA begins ahead of a cold front dropping across the
Great Lakes. This will drive increasingly strong SW winds,
reaching up to 40 kts aloft, which will manifest at the surface
as 20-30 kt winds this evening into Thursday, even with the cold
ocean temperatures. For this reason the ongoing SCA remains
unchanged into Thursday morning for these winds driving seas up
to 4- 7 ft. The weak front will cross offshore during Thursday
bringing a wind shift to the NW and speeds dropping to 10-15
kts, which combined with the offshore component help drop seas
to 2-4 ft.

SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 330 PM Wednesday...Somewhat light wind fields for the
first part of the short term period as a weak boundary will
bisect the waters. Expect northeast winds to the north of the
front with west to southwest winds to the south. Later Friday
afternoon a more consistent southwest flow develops with
stronger magnitudes, 15-20 knots. This direction will be short
lived as a northwest flow develops late Friday maintaining the
15-20 knots. Significant seas will be 2-4 feet through the
period with some five footers possible later across the outer
waters.

LONG TERM /SATURDAY THROUGH MONDAY/...
As of 330 PM Wednesday...A manageable marine period over the
weekend with moderate offshore winds in wake of a dry cold
frontal passage Friday night. As a result, inshore seas will
have limited fetch length for growth, but notably larger seas
will prevail offshore, although no advisories are expected as
weak high pressure passes over then offshore on Sunday. SW-W
winds expected Monday as high pressure settle offshore and SE
of the waters.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until noon EST Thursday for AMZ250-252-
     254-256.

&&

$$

SYNOPSIS...99
NEAR TERM...REK/JDW
SHORT TERM...SHK
LONG TERM...MJC
AVIATION...DL
MARINE...MJC/REK/JDW/SHK


Office: MHX FXUS62 KMHX 140007 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 707 PM EST Wed Dec 13 2017 .SYNOPSIS... High pressure will extend over the area from the south this evening. Low pressure will pass north of the region overnight and push a dry cold front through the area late Thursday. Low pressure will pass near the coast Friday. High pressure will build over the area this weekend. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... As of 700 PM Wednesday...Only minor tweaks to the temperature and dewpoint grids based on current trends. Overall forecast is in great shape. Prev Dis...Surface ridge extending over area from S-SW will crest over area early this evening, allowing winds to diminish and temps to drop quickly in dry air mass. Followed previous forecast indicating min temps 30-33 most inland areas during evening. Clipper low moving across to north will result in winds backing to W-SW by late evening with warm advection continuing into overnight hours, which will be reflected in non- diurnal hourly temp trend with rising or steady temps into early morning hours. Some mid and high clouds will accompany associated short-wave energy but models indicate any precip remaining well north of area due to dry sub-cloud layer. Windy conditions expected for coastal sections overnight but expected to remain below wind advisory criteria. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... As of 300 PM Wednesday...Clipper low will be moving off to N-NE in the morning with pressure gradient weakening and weak frontal passage late in the day. This will basically be a wind shift to N-NE with very limited cold advection indicated. Low level thicknesses will be 30-40 meters higher than on Wednesday, supporting max temps in low-mid 50s. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 330 AM Wednesday...An upper trough will persist across the eastern CONUS through the rest of the week with a series of shortwaves moving through the flow aloft, although expect dry conditions as moisture will be limited. Weak ridging builds into the area this weekend with a system moving into the region early next week bringing a better chance of rain. Thursday night...High pressure briefly builds into the region with lows expected in the low to mid 30s inland around 40 along the coast. Friday and Friday night...Another mid level trough approaches the region Fri and pushes across the region Fri night. Weak low pressure develops across the Southeast in response and lifts across or just off the NC coast Fri. Will likely see more clouds than the previous system but the sub-cloud layer remain fairly dry and not anticipating any precip. The low lifts NE of the area Fri night and deepens with CAA ramping up. Highs Fri generally in the mid to upper 50s with lows in the low 30s inland to around 40 coast Fri night. Saturday through Sunday...Weak ridging and sfc high pressure build into the region this weekend keeping conditions dry. Cool temps expected Sat with highs in the upper 40s to around 50 and lows in the lower 30s inland to around 40 along the coast Sat night. High pressure moves offshore Sun with increasing clouds ahead of the next approaching shortwave. Return flow will bring a warming trend Sun with highs expected in the mid 50s to around 60. Sunday night through Wednesday...A better chance of rain expected early next week as a series of shortwave troughs lift out of the southern plains and lift across the area tapping into Gulf moisture. There remains some spread among guidance, especially with the timing of the systems, so confidence is rather low in this regard but it appears the best chance for widespread precip comes Sunday night and Monday. Slower guidance suggests precip may linger through Tuesday. Temps expected to be above normal this period with predominant SW to W flow across the region. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Short Term /through 18Z Thursday/... As of 7 PM Wednesday...High confidence for VFR conditions to dominate the TAF period. A mid level cloud deck will cross through all the TAF sites late tonight, associated with the low pressure system passing to the north, then skies will clear through the rest of the TAF period. Winds are light and variable, but will increase late tonight from the SW around 10 knots as the pressure gradient tightens. There will be a LLWS threat for tonight as the wind field increases aloft. Long Term /Thursday night through Monday/... As of 4 AM Wednesday...Pred VFR conditions expected through Sunday, then some sub-VFR possible Monday. A shortwave trough and weak surface low pressure push across the region Fri bringing increasing clouds but cigs expected to remain VFR. High pressure builds back into the region over the weekend but will see increasing clouds Sun in advance of the next system approaching the region, with a chance of rain developing Monday. && .MARINE... Short Term /through Thursday... As of 700 PM Wednesday...No update needed as forecast in great shape. Prev Dis...Surface ridge axis extending over area this evening will lead to lull in gusty winds and elevated seas, then clipper low moving across to north will produce tight pressure gradient across waters late evening and overnight. Winds expected to back to W-SW and increase to 20-30 KT all waters with frequent gusts 35-40 KT for central and southern waters including Pamlico Sound. Adjusted headlines accordingly with lighter winds/seas this evening, followed by SCA/Gales developing overnight. Low will move well N-NE of area Thu morning, allowing winds to diminish but elevated seas likely to persist outer waters into afternoon. Guidance continues to indicate increasing W-SW winds will produce water levels 1-2 ft below normal overnight into Thu morning for portions of Pamlico/Neuse rivers, and no change to Low Water Advisory those areas. Long Term /Thursday night through Monday/... As of 415 AM Wednesday...Several shortwave troughs and attendant cold fronts push across the waters through the long term bringing poor boating conditions much of the period. WNW winds around 20-25 kt with gusts around 30 kt with seas around 6-10 ft southern/central waters and 4-7 ft north to start Thu gradually diminishes through the day as low pressure moves off the mid- Atlantic coast. The attendant cold front pushes through late Thu with winds becoming WNW around 10-20 kt, then becomes NE around 5-10 kt with seas subsiding to 2-4 ft Thu night with weak high pressure building in from the north. A weak area of low pressure is progged to move across the waters Fri with winds becoming SW around 10-20 kt by late Fri afternoon, then NW around 15-25 kt Fri night as the low rapidly deepens off the mid-Atlantic and New England coast. Seas build back to 4-7 ft late Fri and Fri night. Winds gradually diminish to W to NW around 10-15 kt Sat afternoon with seas subsiding to 2-4 ft late as high pressure builds into the region. Winds veer and weaken Sat night becoming E around 10 kt Sun morning, then becomes S around 10-20 kt Sun afternoon as the high moves offshore the the next system approaches from the west. Seas around 1-3 ft Sun morning build to around 3-5 ft late in the day. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Low Water Advisory from 10 PM this evening to 10 AM EST Thursday for AMZ136-137. Small Craft Advisory from 10 PM this evening to 10 AM EST Thursday for AMZ130-131-136-137. Gale Warning from 11 PM this evening to 7 AM EST Thursday for AMZ135. Gale Warning from 11 PM this evening to 9 AM EST Thursday for AMZ152-154-156-158. Small Craft Advisory from 10 PM this evening to 3 PM EST Thursday for AMZ150. && $$ SYNOPSIS...JBM NEAR TERM...JBM/BM SHORT TERM...JBM LONG TERM...SK AVIATION...SK/BM MARINE...JBM/SK/BM
Office: RAH FXUS62 KRAH 140022 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 722 PM EST Wed Dec 13 2017 .SYNOPSIS... A fast moving upper level disturbance will move just north of the region tonight, and will be followed by a weak surface cold front that is expected to pass across central North Carolina Thursday morning. High pressure will then build into the area by late Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 652 PM Wednesday... Little if any changes required to the near term forecast. A fast moving upper disturbances and attendant sfc front will cross central NC overnight-early Thu. While system currently producing a notable deck of mid level cloudiness across the central Appalachians, system moving into a very dry air mass. Thus, should see some cloudiness with the system later this evening through 2 AM but likely not to the extent currently being observed to our northwest. Due to the dry air mass, especially below 10000ft, not expecting any precip with this system across our region. The increasing clouds and a steady sly sfc wind will cause temperatures to slowly cool. Once the clouds depart overnight, temperatures will likely drop to near or below freezing by daybreak. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 248 PM Wednesday... Fair weather is in store for Thursday in the wake of tonight's departing short wave trough and the sfc cold front continuing to push south of our area. With the upper flow becoming westerly, look for the high clouds currently located over the central Plains to gradually move eastward and across our area. Otherwise, with low level thicknesses remaining close to their pre-frontal values (some 30-40m higher than today), we should see highs at least 8-10 degrees warmer than today. Overall, Thursday will be partly cloudy with highs in the lower 50s. Thursday evening the low level wind field will shift to the N/NE as high pressure over the Ohio Valley moves east. Although low level thicknesses may drop a few meters on this N/NE flow...increasing high clouds from the southwest should offset the cooler airmass. Lows in the upper 20s to around 30 under partly cloudy skies. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... As of 255 PM Wednesday... A strong upper short wave moving across the Ohio Valley will nudge a reinforcing surge of cold air into the area. Surface high pressure will then build across the area, resulting in plenty of sun, but suppressing high temperatures to the 40s Friday and Saturday. Morning lows Saturday will be mostly upper 20s, with some areas across the south only falling to near freezing. Short wave ridging will be amplifying north into the Eastern Conus by Saturday night, with increasing heights and initiation of warm air advection in return flow as the surface high moves offshore. Cloudiness will be on the increase by later Sunday with highs reaching mostly low and mid 50s after a morning low near freezing. By Monday, a low pressure area will be lifting northeast out of the Gulf of Mexico. There is a good deal of uncertainty as to how the details will play out, with model timing issues as the ECMWF has a strong fast moving short wave race across the Ohio Valley to kick the system offshore quickly, resulting in precip pretty much limited to the southeast, while the GFS's slower short wave allows for a couple of waves to ride up the upper ridge into the area to produce more widespread precip and prolonging the duration of precip chances into Tuesday. Will maintain our ongoing forecast of chance PoPs from Sunday night through Tuesday and allow details to emerge from later model consensus. That said, precipitation type will be no problem with southern stream flow into the area allowing highs Monday and Tuesday to reach the 50s after morning lows in the low to mid 40s. Wednesday looks to be a dry and a bit cooler, but still near seasonable in the 50 to 55 range. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 722 PM Wednesday... There is a high probability of VFR conditions across central NC through 00Z Friday. A fast moving upper disturbance and attendant sfc front will cross central NC later tonight through early Thu. This system will be accompanied by a deck of mid level clouds with ceilings at or above 10000ft. These clouds will depart prior to 12Z Thu. Through 12Z Thursday, there is a threat for low level wind shear in proximity of KFAY and KRWI as winds just a couple thousand feet above the surface will be swly 35-40kts. VFR conditions are expected Thursday night through Saturday night. Another area of low pressure will affect our region late Thu night through Friday. Ceilings associated with this system are expected to remain VFR. A low pressure system approaching from the west may bring a threat for sub VFR ceilings to central NC late in the weekend. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...np NEAR TERM...WSS SHORT TERM...np LONG TERM...mlm AVIATION...WSS