Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/13/23
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
618 PM CDT Tue Sep 12 2023
...Aviation Update...
.DISCUSSION...(This evening through Tuesday)
Issued at 442 PM CDT Tue Sep 12 2023
-- KEY MESSAGES FOR THE ENTIRE 7-DAY FORECAST
(generally chronological order):
* Classic early-fall weather (not too warm/not too cold)
continues this week:
As many (we know not all) reading this likely agree, weather
conditions such as today`s just don`t come much better
(comfortable temps/low humidity/light winds etc.)! Although the
next couple days will likely be very slightly warmer and a touch
breezier, all-in-all things will remain very enjoyable.
* Rain/thunderstorm chances return Thurs night-Fri night (severe
storm risk appears minimal):
Although we don`t want to get folks hopes up too much (especially
for higher amounts), there still looks to be a decent 24-36
window-of-opportunity for at least isolated/scattered (and MAYBE
somewhat widespread) convection associated with the gradual
passage of our next upper trough/weak surface front. Cumulative
rain amounts will surely vary, but latest WPC QPF forecast
generally favors an areal average of roughly 0.25" inch. On a
positive note, the combination of lackluster instability/fairly
weak looks to render any severe storm threat quite minimal. As for
actual rain chances/PoPs, intentionally opted to cap them at 50
percent for now, as was not quite comfortable enough to introduce
"likely" percentages quite yet.
* Drying out and warming up a bit this weekend-early next weekend:
Although we are not talking about an extreme warm-up by any means,
confidence is high that following a cooler Friday (due to more
widespread clouds/precip around), temps will gradually warm up
again as dry weather returns for at least the vast majority of the
Sat-Tues time frame. Although suspect our forecast temps may
still not be quite high enough (especially for Mon- Tues), we are
currently calling for a return to more widespread low-mid 80s for
highs and slightly higher humidity (dewpoints more 50s vs. 40s).
* A peek ahead slightly beyond the official 7-day (turning more
active mid-late week?):
Although far from a sure thing of course, latest ECMWF/GFS
deterministic runs (with support from ECWMF ensemble) suggest a
pattern change mid-late next week, with a western CONUS upper
ridge replaced by a larger-scale (albeit perhaps very slow-
moving/blocked up) upper trough. The net result is the possibility
for increasing rain/thunderstorm chances around the Sep 20-21
(Wed- Thurs) time frame, which is also reflected on the latest CPC
8-14 Day Outlook, which reflects a slight lean toward above
normal precip (time will tell).
-- MORE DETAILS/INFO BUILDING UPON KEY MESSAGES ABOVE (including
all further discussion of Days 2-7 Thurs-Tues):
- Biggest chances versus previous (overnight) forecast package:
Really, nothing very noteworthy. However, on a more minor level:
1) Although they were already limited in area, opted to "push
back" a touch on the default NBM model load (which populates our
longer term periods) and remove all mentionable Pops from Thursday
daytime, as odds favor any activity remaining off to our
north/west until the evening and especially post-sunset.
2) Although previous forecast already had a rain shower mention
for Thurs night, opted to also add in a thunderstorm chance with
this as well, as cannot rule out at least limited lightning
activity.
3) Although previous forecast tended to nudge high temps down for
several upcoming days, this latest package has nudged them back
up...including fairly widespread 2-4 degree increases Sat-Mon (and
perhaps not enough).
- General overview of the large-scale upper air/surface weather
pattern:
Compared to 24 hours ago, the latest ECMWF/GFS runs are in
overall-better agreement...specifically regarding the
placement/timing of a shortwave trough tracking southeastward out
of Canada into the eastern CONUS this weekend (the disturbance
responsible for our Thurs night-Fri night rain chances). Thus, the
general expectations are as follows:
1) Tonight-Thursday daytime:
Our official forecast remains a dry one (and with fairly high
confidence) as we remain under benign northwesterly flow aloft,
and in the grips of a dry/stable airmass.
2) Thursday evening-Friday night:
The aforementioned trough gradually tracks from southern Canada
southeastward into the eastern CONUS, with forcing extending
southwestward into our region (including convergence along a weak
surface boundary). Thus, this time frame contains the vast
majority of rain/thunderstorm chances in the 7-day.
3) Saturday-Sunday:
While most national attention will be on the far northeast U.S.
and Canadian Maritimes for possible Hurricane Lee impacts there,
we are looking at what currently appears to be a very nice
weekend in the wake of the aforementioned passing upper trough,
with weak upper ridging prevailing aloft. Highs in the upper
70s-low 80s with overall-light winds.
4) Monday-Tuesday:
Our surface breezes flip back around to southerly and the flow
aloft starts to transition from northwesterly to more zonal (west-
east) ahead of the potentially more active time frame just beyond
the 7-day. Confidence is fairly high in a more solid warm up into
the 80s, along with increasing low-level moisture/modest humidity
increases. Most of this time frame is probably dry, but both
ECWMF/GFS hint at at least spotty thunderstorm potential as early
as Mon night (for now our official forecast holds off any slight
PoPs until Tues daytime).
-- SHORTER TERM DETAILS FOCUSED SOLELY ON THE NEXT 36 HOURS
(through Wed night/early Thurs AM):
- CURRENT/RECENT WEATHER SCENE AS OF 4 PM:
Wow, what a spectacular day by this forecaster`s personal
definition! Following a seasonably-cool start with widespread lows
solidly in the 40s (including as chilly as 41 at Greeley per our
NWS observer), as was fully expected today has featured plenty of
sun (only pockets of shallow "fair weather" cumulus in spots) and
slightly-cooler-than-normal temperatures, with highs on track to
top out 74-78 most places. Dewpoints have mixed well down into the
low-mid 40s, keeping a distinct lack of humidity going. If
anything, southeast-southerly breezes were weaker/slower to
develop in the wake of a departing surface ridge axis, with most
places this afternoon averaging sustained speeds no more than 5-8
MPH.
- THIS EVENING/TONIGHT:
As any limited, diurnally-driven shallow cumulus fades away, the
stage will be set for another clear/mostly clear and seasonably-
cool night. Really the only difference from last night will be the
presence of very light southerly breezes...only around 5 MPH or
less, but just a smidge more breeze than last night. In theory,
this should keep temps from falling quite as far as last night,
but we are only talking by a couple of degrees in most places, and
have most of the CWA aimed into the 47-51 range, and fully expect
typical cooler spots (such as Ord airport) to reach mid 40s.
- WEDNESDAY DAYTIME:
All in all, another spectacular day for the CWA as a whole. Under
continued benign west-northwesterly flow aloft, we again expect
plenty of sun most areas, albeit probably with a bit more shallow
cumulus and some limited upper level clouds (especially south). In
fact, there are signs that a fairly widespread deck of lower
clouds could actually plague much of western KS, so will need to
watch to make sure some of this more concentrated cloud cover
doesn`t end up getting into especially the Rooks/Phillips area.
There could also be a few spotty/light showers at least somewhat
near the far southwestern edges of our CWA in the afternoon (per
latest HRRR), so this will also need monitored, but have pretty
decent confidence in the going CWA-wide dry forecast. But getting
back to the main message (comfortable, mostly sunny, dry), the
main difference from today is that temps will be slightly warmer
(highs aimed 77-80 most areas) and southerly breezes will be
slightly steadier/stronger (but still only sustained 5-15 MPH).
- WEDNESDAY NIGHT:
High confidence continues in the going dry forecast CWA-wide,
although latest HRRR tries to suggest some spotty sprinkles cannot
be ruled out mainly in KS zones toward sunrise Thurs (something
for later shifts to monitor). Otherwise, its another night of
light southerly breezes, which along with a slightly warmer low-
level airmass, should keep low temps roughly 5 degrees milder than
tonight`s lows...and thus have most areas bottoming out between
52-55. It currently appears that any potential for at least light
fog should remain slightly west of our CWA, but this will also
need watched.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 604 PM CDT Tue Sep 12 2023
VFR conditions expected through the period. Clear skies tonight
with only diurnally-driven cumulus Wednesday afternoon.
Light and variable winds expected to turn to the south on
Wednesday.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Pfannkuch
AVIATION...Mangels
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1029 PM CDT Tue Sep 12 2023
.UPDATE...
Issued at 1029 PM CDT Tue Sep 12 2023
Made just a few touch-ups to the going forecast with tonight`s
evening updates.
First, with a few nearshore buoys still reporting waves around 4
ft as of this writing, have extended the going Beach Hazards
Statement for all four of our lake-adjacent counties through
09Z/400 AM CDT.
Secondly, have introduced a patchy fog mention for our
southeastern CWA. Low dew point depressions at this hour and
light/calm winds seem to point towards at least patchy fog
developing somewhere in the area tonight, especially considering
that some fog developed last night in this same air mass. Cloud
cover remains a bit of a wildcard, though it appears that portions
of interior northwest Indiana and areas near and south of the
Kankakee River in Illinois stand a good chance at having skies
remain clear enough to permit continued good radiational cooling
there through most or all of the night. Guidance has also really
been liking this area to see some visibility reductions tonight,
so introducing some sort of fog mention here felt like the best
course of action. Can`t rule out patchy fog developing elsewhere,
but mixed signals in guidance and low confidence in cloud coverage
remaining sufficiently sparse precluded the introduction of a fog
mention into the forecast grids elsewhere at this time.
Lastly, the going precipitation forecast largely remains in good
shape with isolated/widely scattered showers currently trickling
through portions of northern Illinois as expected. Did opt to
introduce a slight chance thunder mention after midnight for far
northeastern Illinois and our Illinois nearshore waters as it
looks like up to around 500 J/kg of MUCAPE may be present here
right as a localized uptick in convective coverage is advertised
in most of the 00Z CAMs as a 700 mb vort max swings into the area.
It`s possible that most of this activity ends up remaining just
northeast of our forecast area, but the spatial footprint of this
convection depicted in the 00Z CAMs goes far enough south/southwest
to warrant having some thunder mention, in addition to holding
onto high end chance PoPs in this area. There are also some signs
that a lake-induced mesolow could develop as this activity tracks
out over the lake. If this were to occur, then that would enhance
the potential for waterspouts over Lake Michigan late overnight
into early tomorrow morning. However, confidence in this occurring
in close enough proximity to our nearshore zones was too low to
justify an increase to our going slight chance waterspout
probabilities.
Ogorek
&&
.SHORT TERM...
Issued at 305 PM CDT Tue Sep 12 2023
Through Wednesday night...
Early this afternoon, most of the area is seated comfortably
underneath some fair weather cumulus with temperatures in the upper
60s to around 70 degrees. Meanwhile, a broken line of showers and
thunderstorms is building in eastern IA and extreme SW WI, and
another in far SE MN into western WI. Only a couple of models
actually picked up on that first line with this morning`s 12Z runs.
And even the hourly-updating RAP and HRRR are struggling to resolve
this line; in fact the HRRR is dry as a bone out that way for the
next couple of hours. However, the few models that did all have this
first line fizzling away near or west of the I-39 corridor during
the late afternoon. Latest RAP analysis does place an instability
gradient across the region with nearly 1,000 J/kg of SBCAPE in
eastern IA dropping to just a couple of hundred joules in the
northwestern CWA. Additionally, the profile is notably drier over
north-central IL than eastern IA. Despite decent synoptic forcing at
play, the lack of moisture and instability will likely do well to
keep this first line of showers out of the CWA, at least for the
most part.
That second line, however, that`s currently pushing into western WI
looks like a much better shot at seeing some rain in our neck of the
woods. This line is developing in a region of good PVA just east of
the upper trough axis with the aid of a ~30kt 700mb jet max running
along the IA-MN state line. As the upper low continues to swing
across the Great Lakes, this complex of showers is expected to work
its way into the far northern CWA by this evening. Continued height
falls as we await the trough axis are expected to cool the mid
levels enough to get us to as many as 500-600 J/kg of CAPE by this
evening in the far northwestern CWA. However, this instability will
drop off pretty readily following sundown. Therefore, thunderstorm
chances, while already rather marginal, should be confined to areas
west of the Chicago metro and roughly near and north of I-88.
Guidance is hitting the thunder potential much harder across
southern and SE WI where they will see added forcing provided by
that mid-level jet. Scattered showers are then expected to move
across a good chunk of the CWA through the rest of the night and
into early Wednesday morning. Precip chances will remain highest
near and north of I-88 closer to the center of the upper low. The
cooler weather tonight and tomorrow will again result in unstable
conditions over the lake enhancing the precip potential for areas
near lake, especially tomorrow morning. With the vort hanging over
the lake for the majority of the day, lake-enhanced showers could
potentially continue to fall into the afternoon, particularly over
northwest Indiana. This could also possibly lead to a waterspout or
two over the lake tomorrow.
A large surface high will begin dropping into the area from the
north tonight. With the rain expected this evening and light winds
overnight, northwestern portions of the CWA may see some shallow fog
develop tonight, especially if we can get some good clearing with
the dry advection behind the upper low. A mix of clouds and sun
tomorrow morning will turn mostly sunny by the afternoon as dry air
continues flowing in. Tomorrow will once again be a cooler day for
us with highs forecast in the upper 60s to around 70 south of I-80.
With the high centering itself over the region late tomorrow, the
light winds and clear skies provide a seemingly good setup for some
scattered to possibly even widespread areas of fog into Thursday
morning.
Doom
&&
.LONG TERM...
Issued at 202 PM CDT Tue Sep 12 2023
Thursday through Tuesday...
Surface high pressure will be in control across the region
Thursday and Friday. Light winds and mainly clear skies will
promote mild and pleasant daytime highs in the 70s and seasonably
cool overnight lows in the mid 40s to the low 50s. Early morning
fog will also be possible, particularly early Thursday morning as
the surface high moves overhead.
While the end of the week is looking quiet weather-wise, the next
mid and upper level disturbance is set to dig southeastward
across the Upper Midwest and into the western Great Lakes region
Saturday into Sunday. As this occurs, an accompanying surface cold
front is expected to shift into the area sometime later in the
weekend (late Saturday or Sunday). While some threat for showers
exists with the frontal boundary itself late Saturday into Sunday,
it appears the best potential for showers and storms may come for
areas near the lake as a result of lake effect processes as the
cold upper trough shifts overhead on Sunday. While some lake
effect showers can`t be ruled out into Monday, it should be a dry
day for most. Forecast highs through the weekend will generally be
in the low to mid 70s, with readings likely to rebound a bit into
early next week.
KJB
&&
.AVIATION...
For the 00Z TAFs...
ISOLD to WDLY SCTD SHRA expected in the terminal air space
tonight into early Wednesday morning as an upper level disturbance
moves across the region. While SHRA threat is expected to
diminish in the terminal air space by around sunrise Wednesday
morning, robust lake effect SHRA and possibly a couple ISOLD TSRA
are expected to continue over southern Lake Michigan Wednesday
morning.
Light and variable winds expected tonight. Wednesday morning, a
meso-low over Lake Michigan could influence winds at ORD, MDW, and
GYY, resulting a west of due north component at ORD and MDW with
a south or southwest winds at GYY. Winds speeds should remain
below 10KT during the morning. By afternoon as the meso-low pushes
south and dissipates, look for lake breeze to move inland, likely
resulting in a wind shift to northeast during the afternoon.
Timing of the wind shift to northeast is low confidence.
- Izzi
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement...ILZ006-ILZ103-ILZ104 until 4 AM
Wednesday.
IN...Beach Hazards Statement...INZ001-INZ002 until 4 AM Wednesday.
LM...Small Craft Advisory...nearshore waters until 10 PM Tuesday.
&&
$$
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
930 PM EDT Tue Sep 12 2023
.SYNOPSIS...
A boundary will remain nearby through this evening before moving
to the east as a cool front later tonight. A stronger cold front
and its associated upper-level trough will pass through the
area later Wednesday into Wednesday night. Canadian high
pressure will build overhead for late in the week into the
weekend.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
Upper trough across the western Great Lks is expected to
amplify across the northern Mid-Atlantic into the central
Applachians next 24 to 36 hrs hours. As it does so, height falls
will overspread the area tonight leading to large scale forcing
and widespread showers and perhaps a few thunderstorms. This is
already underway per KLWX radar trends and lightning data. Rainfall
amounts are expected to be around a quarter of an inch, except
in northeast MD where moisture convergence and instability will
be maximized and HREF probabilities indicate possibility of
intense rainfall rates and amounts up to 3 inches. In addition,
this area has seen the most rain in the past 5 days or so and
may be the most vulnerable to flooding. For this reason, a Flood
Watch has been issued for Cecil and Harford Counties from 03Z
till 15Z Wed. As far as severe weather is concerned, a low end
threat for a brief spin-up tornado cannot be ruled as low-level
flow continues to increase. The 01Z RAP objective analysis shows
a bullseye in the Supercell Composite field across northeastern
Maryland.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Sfc cold front will be crossing the area after 12Z Wed, but 925
and 850 mb dewpoint fronts will be lagging behind as well as
500 mb trof axis. So, expect the risk of showers to persist
through much of the day particularly east of the Blue Ridge
Mountains. However, with the best moisture and instabillity axis
shifting east of the Chesapeake Bay, expect any flooding or
severe wx to remain well east of the Chesapeake Bay.
Weak high pressure builds over the region for the second half of
the week leading to cooler and fair weather conditions.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
High pressure is expected to remain overhead Friday through Sunday,
yielding dry conditions with normal temperatures. By the
weekend temperatures may gradually warm to near or just above
normal with the high pressure and ample sunshine, though the
further into the extended, the more dependent conditions will be
on the track of Lee. As we continue to monitor Lee, stay up to
date with the latest information on the tropics at nhc.noaa.gov.
For now, dry conditions are expected to continue through the
weekend with a possible weak frontal passage Sunday into the
early part of the work week. Some precipitation is possible with
this fropa, but will depend on how dry the air mass is.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
Showers and possible thunderstorms are expected tonight mainly
through the overnight hours. The greatest chances have shifted
northward given current radar trends. This places the main
threat across the DC terminals initially, before shifting to
KBWI and KMTN within the next couple hours. Some brief cig
and/or vsby restrictions are possible. Scattered showers are
still possible Wed, but most showers should be done by 15Z. As
the upper trough passes overhead, a few showers may fire up
during the afternoon, especially I-66 southward.
VFR conditions are expected Friday and Saturday as high pressure
sits overhead. Thanks to the tight pressure gradient with Lee
offshore, winds both days will be 10-15kt out of the N/NW with gusts
15-20kts, though winds will likely be strongest Friday.
&&
.MARINE...
Widespread showers and isold/sct t-storms expected tonight
through 18Z Wed. A few SMWs may be required. Gradient winds
strengthen late Wed night and remain in SCA category into the
weekend.
SCAs are likely Friday and possible during the day Saturday as a
tight pressure gradient from Lee passing offshore creates gusty NW
winds over the waters. Winds gradually diminish by Saturday night.
&&
.HYDROLOGY...
A Flood Watch remains in effect across Harford and Cecil
Counties from 11 PM this evening until 11 AM Wednesday. This
area has seen the most rainfall within the past 5 days which
would increase the risk for future flash flooding. Toward the
D.C. and Baltimore metros, locally heavy rainfall could lead to
isolated flooding across the typical more vulnerable locations.
The latter threat essentially subsides through the overnight
hours.
&&
.TIDES/COASTAL FLOODING...
With tidal anomalies slightly elevated, a couple of the more
sensitive locations should push into Action stage during the
next high tide. However, water levels should quickly drop off
behind a strong cold front which pushes through midday
Wednesday.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Flood Watch through Wednesday morning for MDZ008-507-508.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...LFR
NEAR TERM...LFR/BRO
SHORT TERM...LFR
LONG TERM...CAS
AVIATION...LFR/BRO/CAS
MARINE...LFR/CAS
HYDROLOGY...
TIDES/COASTAL FLOODING...
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
947 PM CDT Tue Sep 12 2023
...New UPDATE...
.UPDATE...
Issued at 947 PM CDT Tue Sep 12 2023
Midsouth temperatures prevailed in the 70s at 9 PM. MSAS theta-e
surface analysis showed a weak front across north MS, with upper
60s dewpoints to the south, mid 60s to the north. A true
continental airmass prevailed further north, over central MO and
IL, where upper 40s to mid 50s dewpoints were common.
00Z NAM and recent runs of the HRRR model depict mid/upper 50s
dewpoints spreading into areas along and north of I-40 by sunrise.
This modest influx of drier should be sufficient to limit
overnight fog potential. In the interim, the usual spots -
Jackson, and other spots near the TN River, may see brief patchy
fog - if clouds clear more than an hour or two.
Forecast remains on track, with no significant changes needed.
PWB
&&
.SYNOPSIS...
Issued at 232 PM CDT Tue Sep 12 2023
Rain chances will diminish tonight as a cold front brings a return
of drier air and continued cool temperatures to the Mid-South.
Lows tonight will range from the upper 50s middle 60s. Highs for
Wednesday through Friday will be in the upper 70s to lower 80s.
Another cold front will bring a slight chance for showers and
thunderstorms to areas mostly south of I-40 on Saturday, followed
by additional cooler and drier air for the remainder of next
weekend into early next week.
&&
.DISCUSSION...
(This evening through next Monday)
Issued at 232 PM CDT Tue Sep 12 2023
Upper level WV imagery depicts a longwave trough digging south
into the Mid MS Valley impacting the weather pattern within the
MidSouth. Scattered to isolated showers throughout are associated
with a cold front that cut across the region earlier today. High
temperatures area-wide are in the upper 70s due to abundant cloud
cover and rain showers. This activity should diminish by early
evening.
Drier air will continue to filter in on Wednesday with slightly
lower surface dewpoints. Mid-level flow will gradually transition
from northwest to nearly zonal flow with mainly rain free
conditions to persist through Friday. Highs are expected to
remain in the 80s for the remainder of the week but will slightly
increase as shortwave ridging builds across the Lower Mississippi
Valley.
On Saturday, a cold front will produce another round of showers
and perhaps a few thunderstorms. Global ensemble models depict
chances for showers impacting areas mostly south and east of
Memphis. Estimated QPF shows very light rainfall with values only
reaching 3/10 of an inch. Rain showers ahead of this cold front
are expected to only last into late afternoon. Rain-free
conditions are anticipated for late weekend into the beginning of
next week with highs in the lower to mid 80s and lows in the upper
50s to 60s.
&&
.AVIATION...
(00Z TAFS)
Issued at 609 PM CDT Tue Sep 12 2023
Showers are continuing to push out of the region with JBR being
the final terminal with shower activity. Cloud decks will hang
around until towards the end of the TAF period, but will continue
to lift and scatter out. MVFR cigs should remain to the west of
the terminals this evening and winds will remain from the north.
DNM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...GNC
AVIATION...DNM
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
954 PM EDT Tue Sep 12 2023
.SYNOPSIS...
A stalled front just west of the area will dissipate today, giving
way to another cold front crossing the area later tomorrow into
tomorrow night, with ridging building in behind the front late
week through the weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 955 PM Tue...Isolated thunderstorms currently occurring
over the northern coastal plain counties this evening. Expect a
few more storms to continue developing over the coastal plain
through about 6Z in region of best instability. Another night of
calm winds and moist low levels means a renewed risk of patchy
fog, but increasing clouds from the west could play spoiler
especially for areas west of Highway 17. Muggy overnight
temperatures expected, in the low 70s inland to mid to upper 70s
along the beach.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
As of 425 PM Tues...Cold front, and deeper moisture ahead of
it, will advance eastward through Wednesday. Airmass will be
sufficiently unstable to support a bit more widespread
convective activity, with the primary source of lift being
convergence between sea/sound breezes and whatever remnant
outflow from today shifts into eastern NC. Environment is
modestly sheared with the HRRR showing effective shear of 20-25
kt, increasing slightly farther south. Stronger storms could
support primarily wet microbursts as well as locally heavy
rainfall. SPC has areas along and south of US 70 in a Level 1
(Marginal) of 5 risk. Highs will be a couple of degrees cooler,
in the mid 80s for all areas.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
As of 320 AM Tues...Most important features in the long term
are (1) a cold front that will move through the region Wednesday
night, with showers and thunderstorms possible ahead of it on
Wednesday and (2) the combination of strong high pressure over
the Great Lakes that will interact with offshore Hurricane Lee
to bring increased winds and a drier, cooler airmass Thursday
through the weekend.
Wednesday and Thursday...A cold front will push into the region
Wednesday, crossing the area Wednesday night. As moisture
increases out ahead of the boundary scattered showers and
thunderstorms are expected to develop and should briefly become
widespread in the afternoon during peak heating. Marginally
supportive severe parameters will be present, and some storm
organization could lead to a few isolated stronger cells, but
severe weather is generally not anticipated.
Scattered convection will continue Wednesday evening and shift
to the coast as the front enters the NC coastal plain. The front
will push offshore overnight, but dry air will initially be
blocked from moving in by the large circulation of Hurricane Lee
as it moves northward out of the tropics. As a result, shower
chances will continue along the coast overnight and into
Thursday morning before drier air finally moves in later in the
day.
Thursday Afternoon through Monday...Strong high pressure over
the Great Lakes will quickly build southward Thursday behind the
front which will essentially become absorbed into Hurricane
Lee`s circulation. This will bring strong northerly winds to the
area as the pressure gradient tightens, with the potential for
Gale Force winds across the coast and Outer Banks. Another by
product of this setup will be the introduction of a much drier
and cooler airmass to the Carolinas with Autumn-like conditions
expected into the weekend, with highs in the upper 70s to low
80s and lows dipping down into the 50s inland. By early next
week, moderating temps and increasing moisture will bring at
least widely scattered showers and thunderstorms and near normal
temperatures.
Despite passing well offshore, confidence is very high that Lee
will bring dangerous coastal conditions, particularly the
latter half of this week, and possibly into the weekend. See
the TIDES/COASTAL FLOOD section below for more details.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /through Wednesday/...
As of 625 PM Tues...VFR conditions are forecast prevail at the
TAF sites through Wed morning. There is a very small risk for an
isolated shower/thunderstorm this evening into the overnight.
There could also be a brief period of MVFR visibilities in light
fog early Wed morning especially in areas that see some
rainfall tonight. Wed afternoon scattered to numerous showers
and storms are expected to develop vicinity of the TAF sites as
a cold front moves into the area.
LONG TERM /Wednesday night through Sunday/...
As of 320 AM Tues...A cold front moves through Wednesday night,
with drier high pressure bringing prolonged VFR conditions late
week into the weekend with breezy to gusty N winds Thursday and
Friday.
&&
.MARINE...
SHORT TERM /Through Wednesday/...
As of 955 PM Tues...Winds continue southerly at 5-15 kt this
evening. Little change in the weather pattern is expected
tonight into tomorrow. Southerly winds will continue overnight,
becoming light and variable in the morning before sea breeze
development once again drives southeast to southerly flow around
10 kts. Only difference tomorrow will be a higher coverage of
showers and thunderstorms lingering along the immediate coast in
the afternoon, eventually drifting inland. Offshore, ocean
conditions continue to slowly deteriorate as swell from
Hurricane Lee continues to build. Regional buoy observations are
reporting seas of 5-7 feet with a continued period of 13-14
seconds. Offshore, seas continue to slowly rise, likely another
2 feet or so higher than current observations to 6-8 ft.
LONG TERM /Wednesday night through Sunday/...
As of 400 AM Tues...Powerful long period swell (14-16 second
periods) from Hurricane Lee will bring hazardous marine
conditions to the coastal waters through this weekend as it
recurves across the western Atlantic.
Seas will likely build to 6-12 ft by Thursday morning. Swells
will then peak later Thursday or Thursday night at 10-16 ft
north of Cape Lookout, and 7-12 ft to the south with the
addition of northerly wind swell. Seas will then slowly subside
into the weekend, but remain hazardous.
Winds will turn to the north Wednesday night behind the cold
front and strengthen to 15-25 kts by Thursday morning. Winds
will continue to strengthen Thursday to near Gale Force and
continue at this strength through Friday morning. Winds then
drop off quickly Friday night into Saturday to NW 10-15 kts.
&&
.TIDES/COASTAL FLOODING...
As of 435 PM Tues...Hurricane Lee will slowly progress north of
Hispaniola and east of the Bahamas over the next several days,
producing strong, long period southeasterly swell that will
impact the entire eastern seaboard. This longer period swell has
begun to fill in across ENC beaches and much higher waves will
develop tonight through the rest of the week. High Surf
Advisory remains in effect for Hatteras and Ocracoke, the
Northern OBX and Core Banks, and will come into effect for the
Crystal Coast beaches beginning tomorrow morning.
Expect very dangerous surf conditions with large waves, strong
rip currents, and powerful shorebreak into the weekend at all
area beaches. Additionally, the long period (14-18 seconds)
will cause extensive wave run-up, with the potential for
significant beach erosion, ocean overwash, and coastal flooding.
Details on the severity of impacts is dependent on the eventual
track, intensity, and size of Hurricane Lee as it likely passes
offshore late week. Coastal flood headlines may be needed as
early as tomorrow.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement from 8 AM EDT Wednesday through
Wednesday evening for NCZ195-196-199-203>205.
High Surf Advisory from 8 AM Wednesday to 6 PM EDT Friday for
NCZ195-199.
High Surf Advisory until 6 PM EDT Friday for NCZ196.
High Surf Advisory until 8 PM EDT Saturday for NCZ203-205.
High Surf Advisory until 8 PM EDT Friday for NCZ204.
MARINE...Small Craft Advisory until 8 AM EDT Sunday for AMZ150-152-154.
Small Craft Advisory until 2 AM EDT Sunday for AMZ156-158.
&&
$$
SYNOPSIS...MHX
NEAR TERM...JME/MS
SHORT TERM...MS
LONG TERM...SGK
AVIATION...JME/SGK/MS
MARINE...JME/SGK/MS
TIDES/COASTAL FLOODING...MHX