Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/24/17
Area Forecast Discussion
National Weather Service Wakefield VA
949 PM EDT Mon Oct 23 2017
A weakening cold front slowly push through the local area late
tonight into early Tuesday. A second cold front crosses the area
Tuesday night. High pressure builds across the Gulf of Mexico
Wednesday and Thursday...as low pressure lingers from the Great
Lakes to New England.
.NEAR TERM /THROUGH TUESDAY/...
Current analysis indicates sfc high pressure well off the coast,
with low pressure deepening to the lee of the central
Appalachians (this out ahead of parent sfc low over MI). Areas
of showers are overspreading much of the western Piedmont this
evening. Earlier stronger line segments in vicinity of the Blue
Ridge in NC and VA have weakened, with the stronger activity
now in central NC. Little overall change in thinking with the
scenario tonight, with a high shear/low CAPE event expected,
which has prompted a Tornado Watch that extends into the Ern VA
Piedmont and runs through 06z. The best lift/forcing for likely
to categorical PoPs (60-90%) looks to reach to areas west of
I-95 through midnight, then pushing E to the I-95 corridor from
03-06Z, and to the coast from 06-12Z. Strong low level jet and
effective shear values to 50-60 KT (and some directional shear
through 06Z as SSE sfc winds interact with SSW winds in the H85
to H7 layer. The last few runs of the HRRR depict the potential
for some stronger convection to push into S-central VA prior to
06z, with a weakening trend thereafter. SPC has SLGT risk SVR
for SW parts of the local area (shifting to the ern shore Tue
morning). If it all comes together, an isolated severe tstm with
damaging winds and even an isolated tornado can`t be ruled out.
However, more likely it will be just a narrow line of showers
with embedded convection with wind gusts staying below severe
limits (to 40-45 mph). Will continue the mention of locally
heavy rain and strong/gusty winds in the HWO.
Expect skies to turn partly to mostly sunny by late morning W
and by late aftn E...and have continued w/ lowering PoP trend
W-E. Still rather warm as winds remain from the SW, with highs
Tues in the mid 70s W to the lower 80s SE as cold air lags well
behind off to the NW of the local area.
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Latest 12Z/23 GFS/NAM/ECMWF remain in good agreement Tue night
into Wed, but then show some fairly significant differences
with respect to the strength of the upper low over the eastern
CONUS by late Wed/Thu. The ECMWF the deepest/farthest south and
the GFS the weakest/most progressive and the NAM somewhere in
between but genly a little more like the ECMWF.
Will side a little more to the NAM/ECMWF consensus, but not
quite to the extent of how deep the upper low digs south. Thus,
the sfc cold front reaches the coast early Tue night and is
expected to exit the coast by daybreak Wed morning. Any RA
tapers/ends at the coast Tue evening. Lows will range from the
upper 40s west of I-95 to the mid/upper 50s closer to the coast
by Wed morning. Dewpoints also fall from the lower 50s NW to
lower 60s SE in the evening to 40-45F inland and 45F to around
50F by morning. On Wed...local area looks to remain in between
the sfc cold front well offshore and deeper moisture/cold pool
aloft to our WNW. Some SCT/BKN cu will tend to linger due to
some shortwave energy aloft, but should be dry with highs
mainly in the m-u60s (staying a little below MAV numbers as
they are based off the warmer GFS). For Wed night/Thu, siding to
the NAM/ECMWF allows for some digging SE of the upper level
shortwave energy from the Great Lakes through the Carolinas by
thu morning. Will keep it dry for now, with partly cloudy
conditions. Lows Wed night mainly in the 40s and highs Thu 60-65
F under partly to mostly sunny skies.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Long term period starts off dry Thu night/Fri with sfc high pressure
over the immediate area and W/SW flow aloft. With light sfc winds
under a clear sky, expect low temps Thu night in the low/mid 40s
most of the area, and highs in the mid/upr 60s Fri. Attention then
turns to an approaching deep upper-level trough Sat. Although any
pcpn will likely hold off until after daytime Sat, included a 20%
chance of a shower in case the faster ensemble member solutions pan
out. Better chance of rain (40-50%) arrives Sat night/Sun as strong
sfc low pressure forms out ahead of the upper-level trough. There is
still plenty of uncertainty over the track of this low, but the
possibility is there for moderate to heavy rain Sun. High temps in
the mid/upper 60s Sat drop to the upr 50s to mid 60s Sun.
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Low pressure and an associated cold front will approach fm the
west this evening, then the actual cold front will gradually
cross the region and move offshore later tonight into Tue
evening. Increasing SE then S winds expected this evening thru
Tue morning ahead of the front, with showers and possible tstms
moving thru the CWA later this evening into Tue morning. SE or S
winds 10-15 kt, with gusts up to 25 kt possible during this time
period, with higher gusts possible in stronger showers or tstms.
This front will bring the potential for MVFR/IFR conditions in
showers and lower CIGS. Mainly VFR conditions expected later Tue
aftn/evening through Fri.
Previous marine headlines remain in place ahead of an approaching
cold front. Decided to put all headlines in effect with this package
with SCA conditions expected to commence over all wtrs within 12 hr.
The SCA is for 15-20 kt southerly winds over the rivers/Sound and 15-
25 kt winds with gusts up to 30 kt over the Bay and ocean. Waves up
to 4 ft over the Bay with seas over the ocean up to 7-8 ft. A trough
of low pressure ahead of the cold front slides through the area
early Tue, with the pressure gradient relaxing a bit into the day
Tue and winds decreasing to below SCA thresholds. Main cold front
crosses the area Tue night with sub-SCA NW winds expected behind the
front into Wed. Will maintain the SCA over the ocean through the day
Wed due to a prolonged period of 5 ft seas. Lighter winds and sub-
SCA conditions into Thu and Fri with sfc high pressure over the
A modestly strong SSE wind ahead of a cold front will
potentially push tidal anomalies to 1.0-1.5ft above normal late
tonight into early Tuesday morning. This could push some
locations near minor flooding thresholds (mainly Cambridge and
Bishops Head) during high tide late tonight into early Tuesday
morning. Water levels at these locations potentially remain
elevated for the following high tide (aftn/early evening), which
is the higher astronomical tide.
MARINE...Small Craft Advisory until 10 AM EDT Tuesday for ANZ635>638.
Small Craft Advisory until 4 PM EDT Tuesday for ANZ630>632-634.
Small Craft Advisory until 7 PM EDT Tuesday for ANZ633.
Small Craft Advisory until 7 PM EDT Wednesday for ANZ650-652-
Area Forecast Discussion
National Weather Service State College PA
1139 PM EDT Mon Oct 23 2017
A strong frontal system will push colder air into the region
tonight into Tuesday. A second shot of cold air is expected
this weekend. Overall most of the coming 6-8 days the region
will be in a mean trough thus cooler weather will be the norm
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Regional radar at 02Z showing band of rain lifting into
the Laurel Highlands/Northwest Mtns along axis of anomalous
southerly low level jet/PWATs preceding potent shortwave lifting
into the Grt Lks. Mesoscale guidance continues to indicate most
of the rain will come with this north-south band during the
late evening hours over the western half of the forecast area
and during early Tuesday morning across the eastern half of the
Latest guidance indicates increasing low level instability late
tonight ahead of vort max lifting north from Virginia in
conjunction with 850 winds in the 60-70kt range. Thus, expect an
increasing threat of severe weather over eastern Pa late
tonight. Per collaboration with neighboring offices, have
covered much of the region with a wind advisory late tonight.
Bufkit soundings support gradient wind gusts in the 20-30kt
range, but any strong convective cores could easily bring 50+
mph winds to the surface. The v-winds are about 4 to 5 sigma
above normal ahead and along the frontal boundary.
Most areas will have a good 2-4 hour window of rain, with
ensemble mean QPF ranging between 0.5 and 1 inch. In the HRRR
and the GEFS this has a classic NCFRB look so most of the rain
will be close to the frontal boundary.
Rapidly improving indicated across the western half of the
forecast area late tonight behind the line with partial
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Cold front and associated gusty showers/storms should exit the
eastern portion of the forecast area between 12Z-15Z. Model
soundings support a good deal of morning sunshine in region of
large scale subsidence behind front. However, diurnal heating
combined with approach of upper trough axis and secondary cold
front should result in increasing cumulus by afternoon with even
a PM sprinkle possible across the Alleghenies and central
The coldest air does not filter in until Wednesday but Tuesday
will be the start of a cooler period. Enjoy what could be one
of the warmest days for some time to come.
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Surface ridging indicated over central Pa by med range guidance
late Tuesday through Friday, indicating dry weather for most of
the forecast area. The exception will be late Wed, when passage
of shortwave could produce a few showers across the northwest
mountains. Ensemble mean 925/850 temps are slightly below
normal Wed/Thu, likely translating to max temps from the upper
40s over the Alleghenies, to the upper 50s across the southeast
This cooler stretch will be short lived as heights and 850
temps rise quickly into next weekend.
Another chance for precipitation will arrive at the end of the
period when a cold front is anticipated next Sunday, bringing
rain to much of the CWA, while colder air and a few waves of low
pressure riding NNW along the front brings the chance of a light
to moderate, and elevation dependent snow event.
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Rain consolidating into a gusty line...with the leading edge
from near KBFD to KAOO to KHGR. Significant winds with low
level jet continues to strengthen...with surface wind gusts
approaching 40 kts in some locations. Line will continue to
pivot east, and is expected to intensify as instability
With 850 mb winds forecast to be in the 50 to 70 knot range
overnight, expect surface winds to regularly gust between 20
and 30 kt...and between 40 and 50 kts in the vicinity of the
CFROPA. Could also see some isolated thunder in convection
especially over eastern areas. These strong wind fields also
introduce high potential for LLWS pre and during FROPA.
Showers and rain will end rather abruptly from west to east
overnight. With the FROPA, also should see a quick drop in
strong wind gusts. Windshift behind the front will be somewhat
subtle...shifting from the SSE to the SSW. Most notable again will
likely be the noticeable drop off of strongest wind gusts
behind the front.
Ceilings will mainly be in the MVFR range overnight, but a
narrower corridor of IFR ceilings expected to accompany the
front. Visibilities may be restricted in areas of heavier rain,
but should mainly remain in the VFR/MVFR range.
Tuesday will be breezy behind the cold front, with improving
conditions as the front swings east. Showers may linger till
around 12z in the east. More scattered showers will develop in
the mountains in the afternoon. Conditions generally back to
VFR across Central Pennsylvania after about 14-16Z.
Wed-Thu...Mainly VFR, but scattered showers and ceiling
restrictions in the western and northern mountains.
Fri Night-Sat...Another approaching cold front with chance of
Through 10/22/17, the average monthly temperatures at
Harrisburg and Williamsport are 63.8F and 61.8F. When compared
to the maximum 1-month mean avg. temperature for previous
Octobers, both would rank as the warmest on record. Computing
a daily avg. temperature when only taking into account the first
22 days of the month and comparing to the previous Octobers,
the rankings are #2 at IPT and #3 at MDT.
Wind Advisory until 8 AM EDT Tuesday for PAZ028-036-037-041-
Wind Advisory until 4 AM EDT Tuesday for PAZ004>006-010>012-
Area Forecast Discussion
National Weather Service Grand Rapids MI
1003 PM EDT Mon Oct 23 2017
Issued at 328 PM EDT Mon Oct 23 2017
Low pressure moving north across Lower Michigan will continue to
bring heavy rain with some flooding expected through Tuesday. The
low will deepen on Tuesday and winds will be ramping up with some
strong wind gusts Tuesday and Tuesday night.
Issued at 957 PM EDT Mon Oct 23 2017
With the potential for Gales less than 12 hrs away we upgraded the
watch to a warning. No other changes were made to the forecast.
Satellite imagery shows the coldest cloud tops pivoting north of
the region. Radar and rain gage trends show the precipitation is
weakening in intensity. There is still a lot of forcing around
and a very moist airmass in place. Thus it appears mostly light
rain with periods of moderate rain can be expected right into
.SHORT TERM...(This evening through Wednesday night)
Issued at 328 PM EDT Mon Oct 23 2017
Heavy rain tonight into Tuesday and high winds Tuesday into
Tuesday night are the main forecast issues in the near term.
The Flood Watch was replaced with areal Flood Warning across the
western third of the forecast area and an areal Flood Advisory to
its east. The southeast zones are not expected to see flooding and
the watch was dropped there.
Surface low was centered just south of AZO at 330 PM and is moving
north with strong area of f-gen expected to continue producing
inch an hour rain rates across the warning area through the
evening. We have been fortunate that the bulk of the heaviest rain
has remained over Lake Michigan so far today, but amounts over 2
inches have occurred across parts of Ottawa, Muskegon, Oceana
Counties with a report of nearly 2.25 inches near Holland at 320
PM. The heavier rain is moving onshore and the HRRR has the f-gen
area pivoting across our northwest zones tonight.
So 3 to 5 inches of rain is possible in the warning area with
amounts of an inch or less across the southeast zones by Tuesday
The other issue we will have to deal with high winds on Tuesday as
the low rapidly deepens across northern Lower Michigan.
Tightening pressure gradient and strong cold advection will
combine to bring gusts to wind advisory criteria during the
morning across the northern coastal zones and by afternoon across
central and southern zones. We have issued a wind advisory for
this area. The winds will subside after midnight as the low pulls
.LONG TERM...(Thursday through Monday)
Issued at 328 PM EDT Mon Oct 23 2017
Main weather highlights in the long term period are a period of
milder and quieter weather Thursday into Friday, followed by more
cold air for the weekend through Halloween.
Quiet weather day expected for Thursday due to shortwave ridging in
between the exiting upper trough and the next one dropping into the
north central U.S.. Also milder temperatures expected on Thursday
with high temps 55 to 60 as warm advection strengthens in advance of
next approaching system. Friday may also be a mild day if the slower
ECMWF timing of the next cold front is correct.
Deep longwave trough is progged to impact the Great Lakes Region
next weekend, resulting in scattered showers with highs only in the
mid 40s. Some snow showers will be possible at night and in the
early morning when temperatures cool, especially inland from Lake MI
and in higher elevation areas. Any clearing at night could lead to
sub freezing temperatures.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 748 PM EDT Mon Oct 23 2017
With the storm system remaining in the region through
Tuesday...impacts will continue at the TAF sites. IFR/MVFR
conditions will prevail with local VFR possible. As the colder
air wraps in behind the storm for Tuesday lake effect moisture
will keep the ceilings and visibilities low through the day.
Gusts over 25 knots will be possible...especially on Tuesday for
Issued at 328 PM EDT Mon Oct 23 2017
No significant changes to the previous forecast. Winds and waves
will be increasing tonight and gales are still expected to develop
on Tuesday. Northwest gales will probably begin during the
morning across areas north of Whitehall and during the afternoon
south of there.
Issued at 1211 PM EDT Mon Oct 23 2017
River levels are rising across the area. Rainfall of up to two
inches has fallen through this morning and another two to three
inches are possible through Tuesday. More rain is also possible
through the week. Warnings have been issued for Croton on the
Muskegon River, Rockford on the Rogue River, and Vicksburg on the
Portage River. More river warnings could be issued depending on the
amount of rain that falls and where it falls. Areal flood warnings
and watches are also in effect though Tuesday.
MI...Wind Advisory from 2 PM Tuesday to 3 AM EDT Wednesday for MIZ050-
Wind Advisory from 8 AM Tuesday to 3 AM EDT Wednesday for MIZ037-
LM...Small Craft Advisory until 10 AM EDT Tuesday for LMZ844>849.
Gale Warning from 10 AM Tuesday to 8 AM EDT Wednesday for
Area Forecast Discussion
National Weather Service Houston/Galveston TX
953 PM CDT Mon Oct 23 2017
A cool overnight with temperatures bottoming out in the interior
lower 50s...coastal lower 60s. A secondary cold front to come
through and provide a shot of colder...drier air to the region
tomorrow. Strong northerlies in the wake of the front may reach
Wind Advisory criteria along the immediate coastline tomorrow
morning into the early afternoon. Middle 30 to lower 40 degree dew
points...with mid to upper 70 afternoon warmth...will increase
fire weather concerns as daytime relative humidities plummet into
the low to mid 20 percentile through Wednesday. Offshore winds
weaken and return onshore Thursday. The next cold frontal passage
slated for Friday will not have much moisture to work with so
late week rain chances will be low. 31
.PREV DISCUSSION... /ISSUED 624 PM CDT Mon Oct 23 2017/
A reinforcing cold front will be moving through the area later
tonight. Look for winds to increase and become quite gusty during
the day Tuesday. Otherwise...VFR conditions will prevail. 47
PREV DISCUSSION... /ISSUED 348 PM CDT Mon Oct 23 2017/
Mainly a wind and temperature forecast for this afternoon`s
update. Starting at 06Z, short term guidance such as the HRRR and
RAP13, bring a wind shift into the northern zones of the forecast
area, shifting the winds out of the north/northeast. The coast
should see this wind shift by 10Z. The pressure gradient tightens
during this time frame, and as a result winds will pick up to 5 to
9 mph over land between 06 to 12Z. A secondary cold front
following the front that passed yesterday, will act to provide an
additional reinforcement of cooler air. Low temps this evening are
still expected to range in the 50s to low 60s along the coast,
while the effects of this secondary cold front will not truly be
felt until Tuesday. Model guidance has also trended cooler Tuesday
and Tuesday night, with radiational cooling anticipated with
these clear night skies, and therefore decided to lower temps by a
As the surface high shifts southeast, Monday night into Tuesday,
this tighter pressure gradient should cause an increase in wind
speeds throughout the afternoon Tuesday, keeping winds between
10-15 mph over land, with gusts to around 20 mph. Additionally,
as cooler air continues to advect in the region Tuesday, high
temperatures will struggle to make it out of the mid 70s. Tuesday
will also be the driest day this week, with min RHs between 20 to
25%. With these RH values and stronger winds over the area,
elevated fire weather conditions will be of concern. Tuesday night
into Wednesday will be the coolest night before the weekend, with
low temperatures plummeting into the low 40s near Bryan/College
Station to upper 50s along the coast near Galveston.
Highs again Wednesday will struggle to make it into the mid 70s. The
pressure gradient slackens Tuesday into Wednesday, and a stronger
region of high pressure scoots in from the northeast. Therefore,
fire weather conditions will be less of a threat Wednesday. Onshore
winds will return late Thursday as the area of high pressure
weakens. This will help to increase moisture over the region
Thursday afternoon, and by Friday PWs will range between 0.7 to
Timing of the frontal passage late in the week amongst the various
global models is still inconsistent. GFS is still a little faster
than the ECWMF, though the solutions of both have come closer
together in time. Progression of the front through SE TX looks to
occur late Friday afternoon into Saturday morning. Sunny skies
will become partly cloudy as a result of the front Friday
afternoon. The ECMWF also brings in a bit more precipitation out
ahead of the front than the GFS, late Friday into Saturday. In
terms of intensity, the ECMWF is providing the coolest solution in
comparison to the GFS and NAM. Remaining conservative in the
forecast for now, though leaning towards the ECMWF solution.
Saturday into Sunday, 850 temperatures range between 2 to 5 degree
Celsius, which is a touch on the colder side for this time of
year. Confidence remains low on just how strong this front will
be. Therefore, temperatures could trend cooler this weekend as the
models get a better handle on the airmass in the next few days. 08
Winds over the waters are relatively light this afternoon and will
continue so into the evening as high pressure moves east of the
area. Winds should pick up overnight as a front moves through, and
are expected to reach advisory levels over the Gulf by morning. The
advisory begins a few hours before the threshold is forecast to be
met to cover the period of SCEC-level wind. The advisory carries
through Wednesday morning - the 0-20 nm zones may see a bit of a
lull in the afternoon, but with the expectation that winds will
exceed the advisory threshold again tomorrow night, chose to keep
one longer advisory.
Look for winds to diminish Wednesday as another high pressure center
moves across the region. As that high moves off to the east, onshore
flow should return on Thursday. The next front is expected to arrive
Friday, and looks strong enough to bring another period of strong,
gusty winds. 25
Dry air will be reinforced by another cold front overnight. Unlike
today, winds behind the front will be considerably stronger. As a
result, we`ll be looking at an RH and wind combo that is near the
threshold for a red flag warning. Min RHs look to be in the
neighborhood of 25 percent (a touch lower farther inland, a smidge
higher at the coast), with winds also in the 15 mph ballpark and
gusts to around 20 mph. In addition to that, overnight recovery
looks decent, but not outstanding tonight, and even worse Tuesday
night. But, with all that said, we are fortunate to have generally
wetter than normal fuels. Outside of the 10 hour fuels, which are
more receptive to changes in RH, rain from Sunday morning will help
mitigate conditions. Because of that, will decide against going with
any fire weather headlines. However, those with more grassy fuels
should be aware of the dry air and winds expected, and understand
that fire may spread more rapidly than they might expect given the
Low humidity will persist deep into the week, until the return of
onshore winds on Thursday will begin to return moisture back to
Southeast Texas. Fortunately, high pressure drifting across the area
will keep winds lighter than we`ll see tomorrow. This will mitigate
fire weather concerns to some extent for Wednesday and Thursday.
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 52 78 43 76 46 / 0 0 0 0 0
Houston (IAH) 53 76 48 76 49 / 0 0 0 0 0
Galveston (GLS) 61 76 58 73 62 / 0 0 0 0 0
GM...Small Craft Advisory from 4 AM to 4 PM CDT Tuesday for the
following zones: Galveston Bay...Matagorda Bay.
Small Craft Advisory from 4 AM Tuesday to 3 AM CDT Wednesday for
the following zones: Coastal waters from Freeport to the
Matagorda Ship Channel out 20 NM...Coastal waters from High
Island to Freeport out 20 NM...Waters from Freeport to the
Matagorda Ship Channel from 20 to 60 NM...Waters from High
Island to Freeport from 20 to 60 NM.
Area Forecast Discussion
National Weather Service Wilmington NC
849 PM EDT Mon Oct 23 2017
A strong cold front will approach from the west today and slow,
finally moving completely offshore Tuesday afternoon. Showers
and thunderstorms are expected along and ahead of the front with
the possibility for a line of strong to severe thunderstorms
this evening and tonight. In the wake of the front, dry and
cool air is expected through Thursday as Canadian high pressure
takes hold. A warming trend begins Friday. Shower chances
increase Saturday as a weak area of low pressure develops ahead
of a second cold front.
.NEAR TERM /THROUGH TUESDAY/...
As of 830 PM Monday...Axis of surface-based instability was
moving eastward across the Pee Dee region as of 00Z, with LI`s
of -2C to -3C extending from near LBT southward through
Kingstree. Modest surface pressure falls were occurring just
east of this axis of instability, and will transition eastward
and off the coast over the next few hours. Although backing of
the surface winds in response to these pressure falls has been
modest across the CWA, the shear profiles as evidenced by KLTX
VWP will remain conducive for storm rotation through the remainder
of the evening. Latest HRRR indicates the thunderstorm activity
will move off the coast around 06-07Z.
Cool advection lags considerably behind the wind-shift though
dewpoints may start dropping Tuesday afternoon temperatures will
still warm up into the upper 70s, a solid category above
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...Very quiet conditions will settle into
the area as a deep full latitude mid level trough moves from the
Tennessee Valley to just offshore through the period.
Precipitable waters dip to near one quarter of an inch by late
in the period. At the surface a somewhat blustery pressure
gradient will reside across the area and this is reflected n the
guidance. There may be some decoupling early Thursday morning
allowing temperatures to possibly drop to the coolest readings
of the season in some areas with lower to mid 40s area wide.
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 PM Monday...Very cool temperatures start the extended as
Canadian high pressure settles across the area before pushing
offshore Friday. Temps Thursday will likely be about 5 degrees below
climo before recovering to more seasonable temps Friday as the
surface high shifts offshore. Moisture will begin to increase
Saturday on increasing southerly winds as a pre-frontal airmass
returns ahead of a deep mid-level trough pushing through the MS VLY.
This will drive a cold front across the area Saturday night into
Sunday. Ahead of this feature, a weak area of low pressure may
develop and move just off the coast, and while total column
moisture remains confined below 700mb, showers are possible late
Saturday through Sunday morning associated with this feature.
This front will bring the potential for the coldest air of the
season behind it, as 850mb progs drop below 0C and extended MOS
numbers feature values as much as 10 degrees below climo early
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 23Z...Latest radar showing precipitation moving up the SC
coast soon to impact KMYR and KCRE. Light rain already at KFLO
and KLBT with nothing yet at KILM. Forecast for the overnight
period still a bit tricky with VAD wind profile showing some
veering between 8k and 17k with 35 to 45 kt winds. As front
pushes to the east storm motion is moving all cells to the NE at
greater than 30 mph. Impacts will affect all terminals through
the evening/overnight period with high confidence in MVFR and
possible IFR conditions in vsby and ceiling. Have mentioned tstm
across the inland terminals but not to confident at the coastal
terminals although cannot totally ruled out but will not
mention at terminals.
Gusty SSE to S winds will prevail overnight until FROPA and
will mention low ceilings and vsby across KLBT and KFLO with
fog as winds abate behind the front. Weather will improve from
west to east across the terminals. Concern might be for some
wind shear around 03z near the coast but will keep an eye on
this as VAD winds are pretty uniform with the wind speeds from
the sfc up to about 4-5K. main concern for all terminals will be
between 00Z and 06Z before condition slowly improve. After
25/15z VFR conditions across the region.
Extended Outlook... VFR Wednesday through Friday. Slight chance for
NEAR TERM /THROUGH TUESDAY/...
As of 830 PM Monday...Latest buoy obs are indicating strong
southerly winds across the waters, with gusts of 25-30 knots.
Seas at buoy 41013 were running near 8 feet. Latest guidance
suggests winds will diminish late tonight across the SC waters,
and early Tuesday morning north of Cape Fear. Seas will subside
below SCA thresholds beginning early Tuesday south of Little
River Inlet, and by early afternoon across the waters north of
Little River Inlet in the wake of the wind shift. Won`t make
changes to the SCA at this time, but if this timing expectation
holds, we may be able to remove the southern waters from the
SCA a little earlier on Tuesday than 18Z.
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...Northwest winds of 10-15 knots and on
occasion 15-20 knots will prevail across the area through the
period. The persistence will be provided by a very deep and slow
mid level trough at 500mb that trudges across the conus from
the Mississippi Valley. Significant seas will be mostly 2-4 feet
with the higher values across the outer waters with the
LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 300 PM Monday...High pressure moving overhead the waters
Thursday into Friday will create gusty north winds early
Thursday before weakening to less than 10 kts and shifting
slowly to NE Friday, and then E on Saturday. A secondary front
approaching very late Saturday may cause winds to uptick again
at the end of the period. The gusty north winds early will keep
seas elevated at 3-4 ft the first half of Thursday, before
falling back to 1-3 ft Fri and Sat. The increased winds late
Saturday may cause seas to begin to rise again at that time.
MARINE...Small Craft Advisory until 2 PM EDT Tuesday for AMZ250-252-254-