Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/03/18
Area Forecast Discussion
National Weather Service Bismarck ND
1013 PM CDT Fri Nov 2 2018
.UPDATE...
Issued at 951 PM CDT Fri Nov 2 2018
Main update issue tonight is temperatures at the surface and aloft
and resulting snow amounts.
Settled on a mix of the NAM with the RAP/HRRR for snow tonight and
Saturday. The mesoscale models seemed to generally follow the
conceptual model of snow along and north of the 700 MB low,
although amounts might be a bit high. The NAM seemed to have a
better handle on the current cooling aloft and resulting snow over
the southwest. Tonight, the RAP continues to want to bring a nose
of warm air into the southwest, while the latest NAM keeps the
warm air just southwest of the far southwest corner of ND. Baker
which turned over to snow quickly early this evening, has since
turned back to rain and has been rain the last couple of hours,
meaning that warm air is very near to the far southwest. However,
we decided to lean a little more toward the NAM due to the current
snow that is falling, with the mix of some dynamic cooling
effects and higher elevation. Basically a little more of the NAM
this evening is resulting in higher snow amounts over Bowman
county. The RAP would keep the southwest half of the county in
rain. Since its already snowing and latest webcams show snow
continuing, will cool temperatures aloft this evening, yielding
more snow for Bowman county.
Late tonight the higher qpf shifts eastward, with accumulations
far southwest slowing down substantially. The problem late tonight
also shifts east as temperatures remain quite warm mainly along
the Lake and Missouri river from Williston to Bismarck. This
limits snow over these areas. Very late tonight and Saturday
morning, temperatures aloft cool significantly from north to south
and we see a band of higher snow amounts east of the warm
temperatures mentioned above. These are within the advisory area,
so no changes to our current advisory. The only change considered
was Bowman county. Updated amounts range form under 2 inches far
west to just under 4 east, which is right at or below criteria if
you average the whole county. We can see how things go through
this evening and overnight shift can adjust if needed.
Highest snow totals now are mainly along and south of Highway 200,
west of the Big Lake and Missouri river, including Golden Valley
and Billings, Dunn, Stark, Hettinger and Adams counties, and
portions of western Morton and Grant, and eastern Slope and Bowman
counties. Lesser amounts of 1-3 inches along the Missouri from
Williston to Bismarck and east.
Updated products will be sent shortly
UPDATE Issued at 658 PM CDT Fri Nov 2 2018
From webcams, snow has started in far southwest ND. Bowman county
EM relayed that it`s been snowing in Bowman for 2-3 hours but snow
is just starting to stick. Have lowered temperatures through the
evening in the southwest and adjusted snow totals due to these
colder temperatures. Snow does end here first late this evening or
shortly after midnight, before another band drops through
tomorrow. Current totals for Bowman 2-4 inches county are not
into advisory criteria but will monitor through the evening.
UPDATE Issued at 550 PM CDT Fri Nov 2 2018
No significant changes with this update. Populated latest current
sensible weather elements and blended to mid evening values.
Currently, rain has pushed from eastern MT into western ND.
Webcams in Beach, Trotters, Bowman, Marmarth and Amidon all look
wet at this time with no snow. Temperatures were generally in the
upper 30s to lower 40s in western ND. However, Baker MT is at 33F
with snow, so would not be surprised to see some mix or
changeover to snow over higher elevations of western Bowman and
Slope counties.
Main problem tonight will be monitoring temperatures and when rain
does change over to snow. There appears to still be some
disagreement on when this takes place, which would influence snow
totals. Current temperatures are running warmer than forecast this
evening. but as noted above, in areas of heavier precip, and
higher elevations, temperatures are quite a bit cooler. For now
not enough confidence to change the current forecast. We only
slightly delayed the onset of precipitation in the west.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 310 PM CDT Fri Nov 2 2018
Winter Weather Advisory headline for most of western and
central North Dakota is the main highlight in the short term.
Latest water vapor imagery shows our next mid/upper level
shortwave now located over southeastern Alberta. Initial large
scale ascent via warm air advection/isentropic lift processes will
continue to allow rain/snow to form in eastern Montana and expand
into western North Dakota late this afternoon. Rain will
transition to snow this evening west, and across central North
Dakota by around midnight. A 700mb closed low will shift into
southwest North Dakota by 12z Saturday, coinciding with a
pronounced TROWAL. This results in the heaviest snowfall totals of
between 3 and 5 inches and isolated pockets of 6 inch amounts
sandwiched within the I-94 and US 85/83 corridors. Elsewhere,
snowfall totals will mostly range between 1 and 3 inches. The
current winter weather advisory was adjusted to add Golden Valley,
Slope, and Adams counties, given the expected ascent and position
of the mid level low mentioned above. Surface temperatures also
problematic tonight and Saturday morning, as overnight lows around
freezing to the mid 30s will make a significant difference with
accumulations.
The mid level low shifts into South Dakota mid/late Saturday
morning, with the TROWAL lingering over south central and the
southern James River Valley through the afternoon. THus, expect
the snow to taper off from northwest to southeast Saturday, with
south central and the James River Valley holding onto light snow
through the afternoon.
.LONG TERM...(Saturday night through Friday)
Issued at 310 PM CDT Fri Nov 2 2018
A series of clipper type systems will reinforce and maintain below
normal temperatures through the long term period. Western and
central North Dakota remain entrenched with a northwest flow aloft
as a longwave trough will essentially be located from Hudson Bay
south into the Great Lakes and the Ohio valley.
The clipper system Saturday exits the James River Valley Saturday
evening followed by a brief break for central North Dakota through
most of Sunday. Warm air advection processes will lead to light
rain/snow chances Sunday afternoon across the west, then a chance
of snow west/central Sunday night into Monday as another clipper
type cold front pushes through. Precipitation amounts at this time
remain light, up to one inch across the north. Colder temperatures
with highs in the 30s dominate next week and overnight lows in the
20s. Could be colder by the end of next week, however the EC is
not as cold as the GFS at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 951 PM CDT Fri Nov 2 2018
Rain will develop across the western terminals KISN/KDIK by early
evening, transitioning to snow by 03z-06z. Rain will make it into
the central aerodromes around 03z, then transition to snow around
09z. Expect snow across all terminals 10z-18z Saturday. Through
this taf period, expect cigs in the mvfr to ifr range, while vsbys
will deteriorate to ifr/lifr due to snow and fog.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 7 PM CDT /6 PM MDT/ Saturday for
NDZ018>022-031>036-040>042-044>047-050.
Winter Weather Advisory until 1 PM CDT /noon MDT/ Saturday for
NDZ001>003-009>011-017.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...KS
AVIATION...TWH
Area Forecast Discussion
National Weather Service Denver/Boulder CO
912 PM MDT Fri Nov 2 2018
.UPDATE...
Issued at 912 PM MDT Fri Nov 2 2018
Radar data and web cameras in the mountains are showing increasing
snowfall over the last couple hours as the first wave of the
upcoming parade of storms gets going. Mountain road conditions
currently vary from bare and wet on I-70 to snow and slush over
Rabbit Ears Pass. Several inches of snow are expected over the
next few hours according to the latest runs of the HRRR, RAP and
NAM. The ongoing Winter Weather Advisory looks appropriate for
now, and will remain in effect. Strong downsloping will keep areas
along the foothills dry, but areas of precipitation will develop
and increase over the plains after midnight.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 249 PM MDT Fri Nov 2 2018
Satellite and radar imagery show our much anticipated short wave
dropping southeast across the spine of the northern Rockies this
afternoon. The main shot of lift and precipitation was just
reaching western Wyoming and southeast Idaho, and probably an hour
or two behind original schedule. As a result, we now expect the
sharp increase in snowfall to reach the Rabbit Ears Pass to Rocky
Mountain National Park area toward 7 PM, and then the I-70
Corridor closer to 10 PM. Snow intensity still expected to
increase significantly with snowfall rates around 1 inch per hour
later this evening into the early morning hours. Overall, the
moisture depth per latest satellite imagery is limited and
therefore amounts may be reduced by an inch or so. However, the
orographics are very strong (upwards of 40-50 knots at 700 mb for
a few hours this evening), lapse rates improve to 7-8 C/km, cold
advection occurs, and we have strong lift on the nose of the
powerful Pacific jet increasing to 120-130 knots. Those parameters
would help make up for the limiting moisture so overall we`ll
maintain the same forecast snow accumulations at this point.
Snowfall rates will be decreasing later tonight through much of
Saturday with some drying aloft and gradual decrease of the
orographic component. The current Winter Weather Advisory for the
mountains above 9000 feet looks good, with a 5 to 12 inch snow
forecast and hazardous travel due to blowing snow and snow-packed
and icy roads. Road conditions may gradually improve on Saturday
especially in valley locations.
On the plains, we should see a couple showers spill out of the
mountains later this evening with the passage of the mid level
cold front and lift from the upper jet. Most of this precipitation
would be in the form of rain. Later tonight into Saturday morning,
a few snowflakes may mix in but no accumulation is expected given
relatively mild temps.
Other concern is the wind. For this evening, the cross mountain
flow increases to nearly 50 knots, but at the same time the stable
layer is lifting so a brute force event is in the works, and not a
mountain wave event. Cross mountain gradients are near warning
guidance (75 mph gusts), so the gusts to 70 mph in the forecast
are good for mountain tops and exposed ridges across the
foothills. On the nearby adjacent plains, could see a few gusts
around 60 mph before weakening later this evening. Winds on the
eastern plains will increase Saturday with good mixing and
stronger northerly flow. Using forecast soundings and mixed layer
data, most locations east of Greeley to DIA should see speeds of
25-35 mph with gusts up to 50 mph.
.LONG TERM...(Saturday night through Friday)
Issued at 249 PM MDT Fri Nov 2 2018
Active pattern during the long term period with area under fast
northwest flow during the entire extended period. Forecast
Saturday night picks up in relative lull of activity behind
departing wave as shortwave ridging briefly in charge. Continued
northwest flow will keep clouds and wring a few more snowflakes
out of residual moisture, and left chc to slight chance pops in
the mountains but otherwise fair weather through Sunday morning.
POPs increase again Sunday with next approaching 500 mb shortwave
trough. Good upward vertical motion over the area with 150 kt jet
at 300 mb stretching from Pacific NW into four corners area Sunday
night through Monday, putting the forecast area in favorable left
front quadrant. Overall this system will resemble tonight`s, with
most precip in the mountains and little on the plains. Blustery
NW wind again Sunday in the mountains, then spreading out onto the
plains with a cold frontal passage Monday morning in northeast CO.
Broad upper level cyclonic flow aloft over the central US, with
weak surface high pressure over the forecast area through the
first part of the week. Our next shortwave trough in northwest
flow moves across southwest Colorado Wednesday night, and east to
northeast upslope flow on the plains will give better chances on
the plains than the mountains for precip this time around. Have
high chance pops for now. Cold enough for snow Wednesday night,
although too soon for forecast amounts.
Temps...no real airmass change during the extended period, and
with NW flow over the region temps will keep a few degrees below
normal. Lower heights during the week and temps will be a few
degrees cooler in the last half of the forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 912 PM MDT Fri Nov 2 2018
Winds will be tricky overnight. Currently the surface winds at
local airports have de-coupled from the stronger winds aloft.
However, strong pressure gradients will be in place across the
state overnight as the storm system aloft causes pressure falls
over the eastern Colorado plains. As flow aloft increases late
tonight, gusty winds may mix down to the surface, possibly before
sunrise. Gusty west and northwest winds will be the primary
concern through tomorrow as the strong flow aloft remains over the
state.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM MDT Saturday for COZ031-033-
034.
&&
$$
UPDATE...Dankers
SHORT TERM...Barjenbruch
LONG TERM...Hanson
AVIATION...Dankers
Area Forecast Discussion
National Weather Service Charleston SC
1016 PM EDT Fri Nov 2 2018
.SYNOPSIS...
A cold front will move through this evening followed by high
pressure through Saturday night. A trough of low pressure will
bring unsettled weather to the area Sunday afternoon through
Tuesday. A cold front will move through early Wednesday,
followed by high pressure through Friday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The cold front crossed the Charleston Airport just before
03/02z and will clear the upper Charleston County coast within
the hour. A few showers will linger near McClellanville for the
next half hour or so, but rain-free conditions will prevail all
areas for the remainder of the night. Both dewpoints and
temperatures will exhibit a steady fall overnight as post-
frontal cold air advection intensifies. Opted to nudge lows
early Saturday down a degree or so based on the latest high
resolution data. Lows will range from the lower-mid 40s well
inland to the upper 40s/near 50 at the coast with minimum wind
chills running a few degrees colder than that. Low/mid-level
clouds are gradually pushing offshore with the cold front, but
it will take several more hours before the thick cirrus
associated with the upper jet pushes offshore.
Lake Winds: Latest H3R surface and RAP boundary layer winds
suggest a strong wind surge will occur along the warmer waters
of Lake Moultrie tonight as post-frontal cold air advection
intensifies. West winds should peak 20 kt with gusts as high as 30
kt at times, which will allow waves to build to 1-3 ft, highest
central and eastern portions of the lake. A Lake Wind Advisory
has been posted through 8 AM Saturday. Mariners are urged to
remain off the lake tonight due to these hazardous conditions.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Surface high pressure and dry conditions will build back in Saturday
behind the cold front and persist through early Sunday. By Sunday
afternoon, a coastal trough is expected to deepen near the coast as
mid-upper level troughing persists over the central United States,
drifting east. Though some model disagreement remains with locating
the trough axis, POPs will generally begin to increase late Sunday
into Monday as the trough lingers near or over the area.
Temperatures will moderate through the period as flow eventually
veers onshore, bringing increased moisture and warmth.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Scattered showers will remain possible Monday night through
Tuesday as a weak trough persists along the coast. A cold front
will sweep through the area late Tuesday night or Wednesday
morning. Ahead of the front, there may be enough instability to
produce a few thunderstorms in addition to scattered showers.
High pressure will prevail Wednesday into Thursday before
another coastal trough potentially affects the area.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Cold front will clear the terminals shortly after sunset with
VFR conditions thereafter. The risk for rain impacts has
generally ended.
Extended Aviation Outlook: Periods of flight restrictions will be
possible at both terminals Sunday through Tuesday due to shower
and/or thunderstorm activity and associated low ceilings and/or
reduced surface vsbys.
&&
.MARINE...
Tonight: A strong west/northwest surge of winds in excess of 20
kt will occur over all waters tonight as strong cold air
advection develops in the wake of a cold front. Seas will
subside with the offshore flow, ranging from 3-6 nearshore
waters and 5-7 ft offshore waters. Small Craft Advisories remain
in force for all legs through the night.
Saturday through Wednesday: Wind and seas continue to subside
through the day Saturday as high pressure returns to the area
and persists through early Sunday. A deepening coastal trough
and subsequently increasing gradient force will lead to elevated
winds/seas Sunday into early Monday, but latest guidance
indicates conditions will remain just below Small Craft Advisory
criteria. Winds/seas are then likely to increase again Tuesday
into Tuesday night ahead of an approaching cold front.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until 8 AM EDT Saturday for SCZ045.
MARINE...Small Craft Advisory until 5 AM EDT Saturday for AMZ330-352-
354.
Small Craft Advisory until 8 AM EDT Saturday for AMZ350.
Small Craft Advisory until 11 AM EDT Saturday for AMZ374.
&&
$$
Area Forecast Discussion
National Weather Service State College PA
1151 PM EDT Fri Nov 2 2018
.SYNOPSIS...
A wave of low pressure will move rapidly through the region this
evening with brisk and cooler conditions expected on Saturday
on the back side of the departing storm. A brief period of fair
weather will occur on Sunday followed by a new frontal system
by Election Day. Cooler and drier weather will follow for the
second part of Wednesday into Thursday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The strongly forced rapidly moving system is rapidly winding
down with the steady rain over the far eastern edge of the CWA.
Quite a shot of rain with 1-2 inches common over the SE, and
some higher amounts in spots.
Meso anal shows the low pretty much on top of Coatsville in
Chester county. Lancaster-York and Reading all seemed to
experience the passage of a gravity wave feature with a rapid
pressure fall-rise couplet and wind gusts in the 35-45 mph
range.
At any rate, things will continue to wind down through midnight.
From earlier...
A strong jet streak is enticing a frontal surface wave
and a burgeoning area of rain that is racing NE over the region
this evening. A quick interpolation has the back edge of the
steady rain moving into Somerset County soon. The rain will be
ending in the Altoona and State College areas between about 8
and 9PM. Rain will taper to showers over the Susq Valley between
about 10 and midnight.
HRRR shows QPF on the order of 1-2" over the SE from about Adams
County up through Schuylkill and eastward. This area will need
to be monitored for short-term mainly nuisance flooding issues
this evening.
Concern remains that a stray stronger shower could bring down
some of the howling winds aloft, but convective instability is
meager at best. Latest RAP meso anal shows no CAPE and anemic
lapse rates. However dynamics are vigorous associated with a
170+ upper jet streak. GFS progs show 500 absolute vorticity on
the equatorward side of the jet to be strongly negative,
suggestive of an inertially unstable airmass and possibly the
potential for slantwise convection.
One feature to watch will be the upper low pivoting across the
area in the 06-12Z Saturday window. Model consensus has trended
a bit wetter during this time and temperatures will be cold
enough to support rain/wet snow mix over north-central PA.
Surface and road temps remain too warm for accumulation but a
coating on the grass is not out of the question in the highest
elevations >2000ft.
West-northwest winds will direct cooler air into central PA
by Saturday morning with upslope rain/snow showers lingering
over the Laurel Highlands and northwest Alleghenies.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Expect a drying trend through the day on Saturday with clearing
skies into Saturday night. After a few relatively mild days, it
will feel noticeably colder with a brisk/gusty wind adding to
the chill. Gusts in the 30-35 mph range are expected and could
blow around unsecured property. Highs will vary from around 40F
in the northwest mtns to the low 50s in the southeast. 24-hr
maxT change will be -10 to -20 degrees colder than yesterday.
Gusty winds will gradually subside by late in the day.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Not a lot of change for this period. Mainly did edge
temperatures up a little in some periods.
The other change was to go with a dry fcst after Wednesday.
Anyway, skies should clear into Saturday night with temps
bottoming out very close to minT climo. Expect max temps to
moderate a bit on Sunday with clouds increasing by late in the
day.
The early part of next week looks to be rather unsettled. Monday
looks rainy, damp and cool. A deep storm is forecast to move
through the Great Lakes on Tuesday, sending a strong cold front
through central PA for Election Day. Heavy rain is possible
along with a band of low-topped convection. Gusty winds and
cooler air will follow in the wake of this system for Wednesday
into Thursday.
Pattern favors a low lifting northeast late Tuesday, like last
night. The combination of west to northwest flow at low levels
and west to southwest flow at mid lvls, not good for seeing
lake effect late Wednesday into Thursday, thus I did cut most
of the lake effect showers out.
Went with a dry fcst for Friday into next Saturday, largely
based on the 00Z EC, current pattern, and superblend, which
shows a pattern similar to Wednesday and Thursday. Some hints
that southern branch of the jet could phase in better, but many
days out, so will go with a dry fcst for now.
Should current pattern hold, then one would see a cool down
every few days, followed by a warm up and some showers between
systems, with nothing real cold.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Rain and associated vis reductions will end over eastern Pa
late this evening, as low pressure lifts northward into New
England. Behind the storm, upslope flow will yield borderline
ifr/low mvfr cigs along the spine of the Appalachians from KBFD
south through KJST overnight. The drying effect of downsloping
flow should yield progressively better conditions further east,
with borderline high mvfr/vfr cigs at KUNV/KAOO and predominantly
vfr conditions east of there.
A gusty west-northwest wind will develop Saturday morning in
the wake of departing storm system. Bukfit soundings indicate
gusts between late morning and late afternoon could range
between 30-35kts over northwest Pa and 35-40kts over the
southeast half of the state. Lingering low cigs over the western
high elevation terminals should lift to primarily vfr
conditions during the afternoon.
.Outlook...
Sun...No sig wx expected.
Mon...Rain/low cigs possible.
Tue...Rain/low cigs/LLWS possible.
Wed...Gusty west winds possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...Steinbugl
LONG TERM...Martin
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1037 PM EDT Fri Nov 2 2018
.SYNOPSIS...
Clear and cooler conditions move in for the weekend. A series of
storm systems will bring a return of unsettled weather through
the middle of next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1025 PM EDT: A cold front is crossing the area, easily
discerned on water-vapor imagery as the sharp edge of a cirrus
deck. A few very light radar returns are seen as well, and KAVL
did report -RA as these moved overhead. Revised PoPs to include a
mention of sprinkles as the front moves across the Piedmont over
the next 3-4 hrs. Generally clear skies are expected behind the
front; along the TN border, however, upsloping will maintain moist
conditions and clouds/PoPs linger. The setup for NW flow precip
looks pretty typical, with moisture not particularly deep. A small
pocket of shallow instability is seen east of Knoxville that is
producing somewhat better precip rates, but RAP prog soundings
indicate this will not last much longer. If the precip lasts long
enough, it may change to snow at high elevations before ending. Any
snow accumulation will be minimal particularly in light of the
recent warm temps. Updated overnight temp trends by blending in
some of the HRRR, which usually performs well during FROPAs. The
slightly colder values in the mtns did result in a little expansion
of the snow mention there, but over the Piedmont temps shook out
a little warmer initially.
Gusty NW winds will expand across the area in the wake of the
front. They will get especially gusty across the higher elevations
of the northern NC mountains; a wind advisory is in effect for
locations above 3500 feet. Winds diminish overnight outside of
the mountains but will remain gusty across the mountains.
High pressure builds in on Saturday. The pressure gradient relaxes
through the day bringing an end to the winds and gusts. Despite
nearly full sunshine, the air mass is much cooler, so highs end
up around 5 degrees below normal.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 1230 PM Friday: Dry profiles will persist atop the region on
Saturday night and linger through most of Sunday, but with flow
quickly increasing from the southwest through the day on Sunday as
heights fall from the west. Anticipate surface high pressure setting
up from the Mid-Atlantic to the western Carolinas on Sunday, with
maximum temperatures a touch below climo.
Atlantic moisture and weak upglide will then return in earnest
Sunday night. The nose of surface high pressure will remain in a
favorable location for cold air damming on Monday. Will shade
temperatures to the cooler side of guidance and maintain solid
chance to low likely PoPs for light rain showers Sunday night
through Monday.
Meanwhile, a plains low pressure system deepening on Monday will
keep robust, moist, southerly flow in the place across the region
Monday night through Tuesday ahead of an approaching, stronger cold
front. The best 850 mb jet ahead of this system will transit the
area during peak heating Tuesday afternoon. SBCAPE values bubbling
to at least 500 to 1000 J/kg as the last vestiges of the wedge
disappear will ramp up instability and support a severe weather
threat across the region as surface to 3 km bulk shear values top 50
kt by 18Z Tuesday. An HWO mention could soon be needed for the
severe thunderstorm potential.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 1230 PM Friday: A dry slot will wrap in quickly from the
southwest following the strong frontal passage Tuesday night. West
to northwest drying, downslope flow is expected on Wednesday along
with brief surface high pressure crossing the area. Good insolation
and downslope warming will keep maximum temperatures above climo
despite the cooler thicknesses.
A weak, reinforcing front will cross the area from the northwest
Wednesday night into Thursday. This boundary will likely stall
somewhere over the southeast, with weak return flow moisture
possibly developing over the front on Friday. Uncertainty is quite
high on the progress of the front across the southeast, so PoPs will
remain quite conservative. Temperatures will fall below climo by the
end of the week.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Winds will veer to NW and maintain modest
speeds in the wake of a cold front tonight. Some guidance members
depict gusts persisting overnight, but downstream of the mtns they
have been overdone compared to obs so far this aftn/evening. Gusts
should be somewhat infrequent. A few patches of MVFR cloud cover
remain, but these will dissipate as drier air advects in. Cirrus
will depart by morning. Winds will settle down and veer around
to NE in the Piedmont over the course of the day as high pressure
centers over the region.
Outlook: VFR should prevail through this weekend, with high pressure
building in from the north. Unsettled weather will return through
early next week as a series of frontal systems moves in.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 98% High 97% High 100% High 100%
KHKY High 100% High 100% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory until noon EDT Saturday for NCZ033-049-050.
SC...None.
&&
$$
SYNOPSIS...RWH
NEAR TERM...RWH/Wimberley
SHORT TERM...HG
LONG TERM...HG
AVIATION...Wimberley
Area Forecast Discussion
National Weather Service Lincoln IL
856 PM CDT Fri Nov 2 2018
.UPDATE...
Issued at 856 PM CDT Fri Nov 2 2018
Isolated showers continue this evening from near Galesburg to
Lawrenceville as an upper level trough continues to progress
through the area. This should end in another couple of hours as
the trough progresses east and a shortwave ridge approaches from
the west. The next low pressure system will be taking shape in the
central Plains overnight promoting an initiating of light SE winds
by morning as well as partially clearing skies. The clearing will
help to promote fog and stratus, however the light winds suggest
that visibilities will not get particularly low, and low stratus
may be dominant. HRRR model runs this evening have continually
suggested stratus developing before a visibility reduction, also
hinting at this. Updates this evening have been to extend the area
covered by isolated showers, as well as to bring a broad area of
patchy fog to most of central and southeast IL by morning.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 246 PM CDT Fri Nov 2 2018
Abundant cloudiness persists over central and southeast Illinois
as a shortwave moves across the state this afternoon. Once the
wave gets by us this evening some partial clearing is likely.
However, short-term models suggest that a nocturnal inversion will
develop and combined with above average boundary layer moisture
content should bring a potential once again for patchy fog across
the region. NAM suggests that the inversion should be rather deep
which may lean toward more of a low-cloud scenario rather than
fog. Will add patchy fog to some of the grids, but do anticipate
vsbys as low or as widespread as this morning.
Progressive flow continues as waves dive into longwave trough over
North America. next wave is already moving in by late Saturday.
Mid-level clouds ahead of the system should inhibit mixing and
keep low clouds around through much of the day. Clouds should
also keep highs a bit below normal despite increased warm
advection.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 246 PM CDT Fri Nov 2 2018
Saturday Night wave will bring precip to the area into the
afternoon Sunday, However, the progressive pattern continues with
waves passing through the trough every 24-36 hours. Models are
relatively consistent with timing of a stronger wave digging in
and approaching Monday, though they do differ some on strength.
The GFS exhibits strong cyclogenesis as the wave enters the
Midwest. With the developing low-level jet ahead of this low
pumping abundant Gulf moisture into the Midwest, dew points should
climb overnight possible reaching into the upper 50s to lower 60s.
With abundant deep moisture, and strong dynamics and shear,
thunderstorms will be likely with some being strong across eastern
Illinois.
As the intensifying system gets northeast of Illinois on Tuesday
much cooler air will advect into the state with strong subsidence
allowing 40-50 kt momentum winds to work down to the surface. This
package will increase gusts to around 30 kts due to some
differences in model strength, but there is potential for
significantly higher gusts with some of the model solutions. This
situation will be monitored closely.
Colder air will continue to filter into the Midwest with each
wave providing reinforcing cold air advection. Temperatures by the
end of the week will likely be around 10 degrees below normal. The
Gulf should be cutoff as high pressure builds into the southeast
for mid-week. But in this progressive pattern, dry conditions
don`t last long and the extended range models bring in the next
chance for precip by late Thursday. There are some significant
differences with the thermal profile with this late week system
with GFS substantially cooler than the ECMWF. The GEFS mean
supports an even colder forecast than the operational GFS. We will
have to watch the evolution of the pattern closely with an eye
toward precipitation type.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 639 PM CDT Fri Nov 2 2018
The main aviation weather impact for the upcoming 24 hours is the
potential for fog and low stratus cloud cover late in the night
and into Saturday morning. Currently VFR conditions are occurring
across central IL although some isolated MVFR cigs are occurring
just to the southwest in isolated -SHRA. Overnight, some breaks in
cloud cover are expected as a shortwave high pressure ridge moves
into the area. The partial clearing could promote formation of
fog and low cloud cover, with light southeast winds developing to
indicate perhaps the low cloud cover will be more significant
with visibility reduction in fog being less of a factor.
Nevertheless, IFR to low MVFR conditions are forecast from around
9Z-16Z to account for this. Winds light and variable, increasing
out of the southeast through the forecast period, with wind speeds
reaching 8-12 kts by 18Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SHORT TERM...Barker
LONG TERM...Barker
AVIATION...37
Area Forecast Discussion
National Weather Service Memphis TN
819 PM CDT Fri Nov 2 2018
.UPDATE...
A shortwave continues to move through the Mid-South this evening.
The shortwave has kicked off some showers and a few embedded
thunderstorms. The shortwave will push east into Middle Tennessee
and North Alabama by midnight ending the chances for rain. Updated
earlier to adjust POPS accordingly. Expect skies to clear out
quickly behind the system. The HRRR is even showing some fog
developing across Northeast Arkansas and the Missouri Bootheel by
sunrise. Have added mention of fog for now, but VSBYS will need to
be monitored through the overnight hours for a potential Dense Fog
Advisory. Will send another update during the late evening hours
to get rid of evening wording.
KRM
&&
.DISCUSSION... /issued 259 PM CDT Fri Nov 2 2018/
Skies are partly to mostly cloudy across the forecast area this
afternoon with temperatures ranging from the upper 40s to upper
50s. Some light rain showers are moving across central portions of
the forecast area at this time. The showers are associated with
an upper level trough moving through the region. As this trough
moves into the Ohio Valley tonight, the light rain showers will
also move out of the region. Temperatures will be on the chilly
side with lows Saturday morning from the mid 30s to lower 40s.
Some parts of west Tennessee and extreme northeast Mississippi may
seem some patchy areas of frost overnight.
On Saturday, high pressure will be centered over western Georgia
keeping things dry across the region. With south winds bringing
milder air into the region, temperatures will be warmer with highs
in the mid to upper 60s. On Saturday night, a warm front will lift
north into north Mississippi with showers and isolated thunderstorms
possible mainly west of the Mississippi River. Temperatures will
be milder Saturday night with lows Sunday morning in the upper 40s
to mid 50s. On Sunday, a weak cold front will push through
Arkansas and into the forecast area. Widespread showers and
thunderstorms are expected on Sunday. Temperatures will be a
little cooler than Saturday with highs in the mid 60s. The cold
front will start to fall apart Sunday night with only isolated
showers expected.
A stronger weather system is expected to move into the central
plains Monday morning and move into western Illinois by Tuesday
morning. As this system approaches the region, a few showers are
possible during the day on Monday. There will be a much better
chance of thunderstorms Monday night as a cold front approaches
the region. There is a chance that some of the thunderstorms could
be severe Monday night into early Tuesday morning with damaging
winds and large hail as the main threats. Isolated tornadoes are
also possible. This system is expected to move quickly out of the
region with the threat of thunderstorms ending Tuesday morning
from west to east. A few showers may linger over eastern sections
of the forecast area Tuesday evening.
High pressure will briefly build into the region on Wednesday with
dry weather and below normal temperatures. Another cold front will
drop through the region from the north Wednesday night and Thursday
morning brining a chance of showers ahead of it. An upper level
disturbance is expected to move the region Thursday night and next
Friday bringing a few more showers.
ARS
&&
.AVIATION...
Upper trough moving through the Mid-South this evening with
scattered SHRAs and a few TSRAs. Some storms could contain small
hail. Trough axis will move east later this evening with SHRAs
ending from west to east. Expect mainly VFR conditions through
the period however, as skies clear this evening some patchy dense
fog may develop in the KJBR area. Winds will be light through the
overnight hours then increase to around 10 kts from the south on
Saturday.
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Blacksburg VA
1106 PM EDT Fri Nov 2 2018
.SYNOPSIS...
A low pressure area over the southern Appalachians will move east
across the area early tonight. A cooler air mass moves in tonight,
bringing a period of gusty northwest winds to the southern Blue
Ridge mountains. Quieter weather expected for the weekend as high
pressure builds in. Unsettled weather then returns to the region
into early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1100 PM EDT Friday...
Showers associated with the passing cold front have for the most
part cleared the eastern sections of the region. There could be
a stray shower or two across this area the next hour or so.
Upslope precipitation in the west will begin to increase in
cover in a few hours. A secondary shortwave trough is expected
to progress eastward along the Ohio Valley through the night,
with increasing 850mb winds on its southern flank racing into
our region. Showers will be on the increase across mainly
southeast West Virginia and portions of southwest Virginia
through daybreak Saturday. Some of higher locations across far
western Greenbrier County will be cold enough for the rain
showers to switch to snow showers and bring light accumulation.
As of 745 PM EDT Friday...
Weather situation quieting down rather quickly as the upper
support/trough moves rapidly east of the area. Convective line,
which so far has failed to produce any lightning (IC or CG) is
along the eastern border of the CWA and rapidly shifting east.
As the upper low sags southward into WV, would expect upslope
showers and potentially snow showers to evolve in the higher
elevations. T/Td generally on track, so no major changes needed
there. Decreased pops for the next few hours as the
precipitation has moved further east.
As of 327 PM EDT Friday...
A pretty busy next 12 hours, with gusty showers/embedded thunder
this afternoon and early tonight, gusty post-frontal northwest winds
overnight into early Saturday.
Ongoing light to moderate-intensity rain currently is spreading
across the western half of the forecast area, ahead of a surface low
near the southern Appalachians. To the east of this low, composite
radar mosaic reveals a fine line of heavy rain showers across the
central Piedmont of North Carolina southward into central South
Carolina. Due mostly to overcast skies, air mass hasn`t destabilized
very well at all with CAPE values mainly less than 300 J/kg. Strong
mostly unidirectional southwest flow still exists across a good
portion of the southeast US, contributing to strong deep-layer wind
shear values. Low-level shear values also are quite stout across the
Carolinas (0-1km shear magnitudes of 30 kts) and should continue to
increase across the foothills and into the VA/NC Piedmont and
Southside. Overall a high shear but very low CAPE environment with
still a concern for at least gusty winds capable of producing
sporadic instances of wind damage associated with the fine line of
heavy showers/embedded thunder, which per HRRR and 3-km NAM,
progresses north-northeast from Yadkin and Surry Counties eastward
into Stokes, Rockingham and Caswell Counties on northward across
Southside and into the Lynchburg area between 4 pm and 8 pm. Have
included enhanced wording for gusty winds for these eastern areas.
While the threat is quite low, given low LCLs and aforementioned
strong 0-1km wind shear, an isolated spin-up tornado is still
possible embedded within this fine line. But the primary threat in
terms of overall messaging is gusty to locally damaging winds. SPC
still has a Marginal Risk area from Yadkin County to Amherst County
eastward Further west, look for light to moderate intensity rains to
continue through the early evening hours.
Have opted to hoist a Wind Advisory for the southern Blue Ridge
south of Roanoke from Floyd to Watauga County from 8 PM tonight to
noon Saturday. Per the GFS, strong pressure rises are expected to
commence this evening as winds shift to northwest behind the cold
frontal passage. So we should see an increase in winds and gusts as
this process occurs. However, a favorable overlap of strong pressure
rises and 850 mb northwest winds of 40-45 kts is expected after
midnight mainly along the southern Blue Ridge. Peak MAV wind speed
at Boone of 21 kts occurs at 09z. While wind gusts in the western
mountains may approach 30 to 35 mph overnight, in the Advisory area
peak wind gusts are expected to range in the 45 to 50 mph range from
after midnight into mid-morning Saturday.
Digging mid-level shortwave trough into western TN and mid-level dry
slot ahead of it should result in a decrease in shower coverage and
push severe threat eastward into eastern Virginia by early this
evening. Any leftover showers should be mostly associated with the
trough`s passage across the western mountains later tonight. Noted
the 12z GFS has trended cooler with its low-level thermal profile
for the overnight hours, with 0 to -2C 850 mb temps from the Blue
Ridge westward. Expect rain showers to then transition to snow
showers after midnight across western Greenbrier County, with any
leftover rain briefly mixing with wet snowflakes above 3500 ft
before ending across the Mountain Empire and NW NC mountains.
However, the best chance of accumulations is across western
Greenbrier County where I`ve shown snow totals of up to an inch from
Quinwood, Rainelle and Duo. Shown lows tonight in the mid/upper 30s
along and west of the Blue Ridge, with lows in the mid/upper 40s
across the Piedmont and Southside.
High pressure is expected to build across the area on Saturday, with
leftover breezy conditions generally easing through the afternoon.
Looking at dry conditions with plentiful sun expected After leftover
mountain upslope clouds and light showers erode around midday, all
areas should see plenty of sun with highs in the upper 40s to the
upper 50s.
Overall confidence is moderate to high, though is lower on
coverage of potential gusty winds late this afternoon.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 327 PM EDT Friday...
During this period of the forecast, we remain in a deep southwest
flow with shortwaves lifting to the north just west of our forecast
area. This erodes a wedge of high pressure at the sfc Sunday and
allows an influx of moisture Sunday night and Monday,with PWAT
values increasing to 1-2 standard deviations above average.
This will help generate showers, especially Sunday night into early
Monday, as a sfc low and associated trof moves north along NC/VA
coast.
This system shouldn`t be overlooked, as SREF spreads show the
potential for some healthy precip amounts, especially in the eastern
portion of the forecast area which the latest ECMWF now advertises.
Some Ensemble River Forecast members push the Dan River at South
Boston into action stage. This potential for localized flooding will
be added to the HWO.
Used a blend of guidance for highs Sunday, but trimmed guidance
highs Monday with an abundance of clouds that arrive late
Sunday.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 327 PM EDT Friday...
Our forecast area, along with the entire eastern U.S. will be
dominated by a broad upper level trof. Prior to the development of
this broad trof, a dynamic, negatively-tilted upper trof lifts
northeast into Great Lakes and pushes a cold front through our area
Tuesday. While the long-range models are in good general agreement
with this scenario, there is still a good spread in the ensemble
members with regard to the amplification of this upper trof, with
the 00Z/02 ECMWF deeper, which allows for a better influx of deeper
moisture into the region. Still, as noted by the SPC 4-8 day
outlook, the potential exists for severe weather with this system
and will be added to the HWO.
Lingering upslope precipitation continues into Wednesday morning.
Above well above normal temps on Tuesday, temperatures fall to below
to near normal for the rest of the long term period. Significant
model differences late in the forecast period with the GFS notably
wetter than other long-range models for Friday and kept small POPS
in for this period.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 800 PM EDT Friday...
Main line of convection has shifted to the east. Ceilings east
of the Blue Ridge are mainly MVFR to VFR behind the line of
convection. Conditions east of the Blue Ridge will generally
become VFR through the rest of the TAF valid period. West of the
Blue Ridge, skies will be holding largely in the MVFR to IFR
range overnight thanks to increasing upslope conditions. Light
rain showers will develop across eastern WV and southwest VA
overnight as the upper low digs southward and closes off in that
region overnight. Visibility restrictions will be MVFR at the
worst in -SHRA, but mostly VFR
Conditions should improve fairly quickly during the day Saturday
as the upper trough lifts out quickly in the highly progressive
pattern. VFR conditions should prevail across most of the region
by afternoon. Winds will become west to northwest 8-12kts with
gusts 20-30kts west of the Blue Ridge, decreasing by Saturday
afternoon.
/Forecast Confidence Levels/
Ceilings - Moderate,
Visibilities- High,
Winds - Moderate,
Precipitation Chances - Low.
Extended Discussion...
VFR Sat afternoon into Sunday as high pressure builds in. A
strong weather system will move into the area. Widespread
rainfall will develop across the area Monday into Tuesday as
the first of a couple of major weather systems digs into the
southeast U.S. and takes on a negative tilt. Winds, low
ceilings, and low visibilities in showers and thunderstorms can
be expected, with a period of high winds possible.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Wind Advisory until noon EDT Saturday for VAZ015>017.
NC...Wind Advisory until noon EDT Saturday for NCZ001-002-018.
WV...None.
&&
$$
SYNOPSIS...AL
NEAR TERM...AL/DS/RAB
SHORT TERM...PH
LONG TERM...PH
AVIATION...AL/RAB