Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/04/23
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
904 PM EST Tue Jan 3 2023
.SYNOPSIS...
High pressure continues to move offshore this evening. Rain
chances hold off until after midnight with the bulk of the rain
falling tomorrow afternoon, as a cold front approaches and
pushes into the region. Temperatures will fall back to around
average by the weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 900 PM EST Tuesday...
Evening analysis shows low pressure over IL with a warm front
extending to the east across northern IN, OH, and PA. Mid and
high level clouds have moved in from the SW with radar showing a
few echoes aloft over the SW corner of the CWA. This precip is
likely not reaching the surface with low reflectivity and dew
point depressions still running 5-10 degrees. Cut PoPs back for
much of the overnight with chance PoPs confined the south and
southwest prior to sunrise. Temperatures have been roughly
steady through the evening and are not expected to fall much
given continued warm advection, winds 5-10 kt, and increasing
cloud cover. Lows in the upper 50s to low 60s will obviously be
well above seasonal norms and record high minimum temps are
likely in jeopardy at a few sites. See climate section below.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
As of 250 PM EST Tuesday...
The low pressure system (currently over the Plains) becomes
vertically stacked as it slowly tracks into the Great Lakes from Wed-
Thu. The associated cold front will cross the region Wed night-Thu
AM. Very mild/breezy with a noticeable increase in humidity on Wed.
S-SW winds are expected to gust to ~25 mph and dew points will rise
into the low-mid 60s by late in the day. Forecast highs range from
the upper 60s W to the mid 70s SE. Hi-res models disagree on just
how much rain the FA will see from this front. HRRR is the most
aggressive so far, bringing a decently strong (for January) line of
showers/tstorms through the area, while other models mostly break up
the line once it gets here. Decided to limit highest PoPs to the
northwestern third counties during the early afternoon hours (~70%).
Lowered the PoPs to 50-60% as the progresses E later in the
afternoon/evening. The front and associated precip should be
offshore by early Thursday morning. Regarding thunder, still
sticking with a slight chance in the afternoon. SPC is maintaining a
MRGL Risk for severe wx across SE VA/NE NC on Wed (mainly during the
aftn/evening), but there is still a lot of spread in the guidance,
and am not confident that we will see enough instability to break
the capping inversion evident on model soundings between 850-700 mb.
CAA will be very weak w/ the initial FROPA. Lows Wed night generally
in the 50s. Highs Thu in the 60s (but with noticeably less
humidity). A secondary (stronger) push of CAA arrives Thu night as
the low pressure system tracks into srn Ontario/Quebec. Still above
average Thu night with lows in the upper 30s-mid 40s. The low
pressure system (at the sfc and aloft) will finally cross the
Atlantic Coast and move offshore Friday into Saturday. Areas along
the MD Eastern Shore could see some light rain associated with this
Friday. Much cooler on Fri with highs in the low-mid 50s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 250 PM EST Tuesday...
Expecting mostly dry weather through the weekend. The deterministic
global models show a weak system tracking across the area (bringing
light rain to NW portions of the FA) late Sat-Sun AM. Added a slight
chance of showers for these areas, but given the dry air at the
surface, would not be surprised if not much made it to the ground.
Seasonable temperatures return this weekend as high pressure builds
to the north. Highs will mainly be in the mid 40s-lower 50s from Sat-
Mon. Lows Sat AM in the upper 20s-mid 30s, then 30s Sunday morning,
and upper 20s-mid 30s Mon AM.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
As of 630 PM EST Tuesday...
VFR conditions in place this evening with some scattered to
broken mid and high level clouds streaming into the region from
the W and SW. Winds at the terminals are generally SSW 10-15 kt
as the gradient remains tight between high pressure offshore and
an approaching cold front. Some LLWS noted on forecast soundings
that will likely persist well into tonight. CIGs gradually lower
from W to E by early Wednesday morning with IFR conditions most
likely at RIC and SBY and MVFR to the SE. SW winds increase
after sunrise with gusts 15-20 kt. Showers move in from the west
by early afternoon with the chance for some thunder, especially
at the SE terminals, though not confident enough in
timing/coverage to mention specifics yet.
Outlook: the cold front will push offshore by early Thursday
morning. Other than a slight chance of showers at SBY on Friday,
expecting dry and VFR conditions through the weekend.
&&
.MARINE...
As of 250 PM EST Tuesday...
This afternoon, high pressure is located well offshore and a slow
moving cold front is located west of the region. SSW winds have
increased this afternoon due to the tightening pressure gradient
between the two systems. SSW winds are generally 10 to 15 knots with
gusts to ~20 knots. Seas range from 2 to 4 feet, and waves in the
Chesapeake Bay are running around 2 feet.
Winds will increase to around 15 to 20 knots with gusts up to 25
knots across the bay and 20 to 25 knots with gusts up to 30 knots
across Atlantic coastal waters later this evening into tonight.
Winds will likely peak this evening. Small Craft Advisories remain
in effect for the Chesapeake Bay, Lower James, and coastal waters
north of Cape Charles through tonight. The SSW winds will continue
through Wednesday, but there may be a period of lighter winds early
Wednesday morning before increasing again during late morning and
afternoon. Therefore, have still held off on any additional SCAs,
but SCAs will likely be needed again for at least the coastal waters
Wednesday evening and overnight. The cold front is forecast to move
off the coast early Thursday morning. Winds will weaken behind the
front and turn from the NW on Thursday, as there will not be much
cold air advection immediately following this front. NW winds will
increase later in the week as colder air moves into the region.
Waves in the bay are expected to increase to around 3 ft later today
through Wednesday as southerly winds increase. Seas north of Cape
Charles will increase to 3-6 ft, and 2-5 ft south later today though
Wednesday.&&
.CLIMATE...
As of 630 AM EST Tuesday...
Very mild-warm wx is expected through Wednesday, possibly
challenging a few daily records at long-term climate sites which
are listed below.
Record Highs:
* Site: Tue 1/3 Wed 1/4
* ORF: 76 (2004) 78 (2004)
* RIC: 74 (2000) 76 (2005)
* SBY: 70 (2000) 72 (2000)
* ECG: 73 (2000) 76 (2000)
Record High Mins:
* Site: Wed 1/4
* ORF: 62 (2004)
* RIC: 57 (2004)
* SBY: 60 (1950)
* ECG: 60 (2015)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 4 AM EST Wednesday for ANZ630>632-
634-638.
Small Craft Advisory until 8 AM EST Wednesday for ANZ650-652-
654.
&&
$$
SYNOPSIS...RHR
NEAR TERM...RHR
SHORT TERM...AM/ERI
LONG TERM...AM/ERI
AVIATION...RHR
MARINE...AJB
CLIMATE...
AREA FORECAST DISCUSSION
National Weather Service Albany NY
959 PM EST Tue Jan 3 2023
.SYNOPSIS...
warm front will continue to bring scattered
showers and patchy drizzle overnight. Temperatures will remain
steady or slightly rise with plenty of clouds, as the front stalls
over New York and central New England. As the front returns back
southward on Wednesday, temperatures will be falling through the day
after a mild start, with more rain for late Wednesday into Wednesday
night. The rain may change to a wintry mix across northern and
eastern parts of the area for Wednesday night into Thursday. Some
lingering rain or snow showers may continue into Friday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
.UPDATE as of 958 pm EST...The warm front is just north of the
NY-PA border and extends eastward into southern NY and southern
New England. The rain shield has dissipated and transitioned
into scattered to numerous showers with some patchy drizzle. The
water vapor loop shows the short-wave has moved east of the
region near southeast New England.
The 00Z 3-km HRRR continues to show a weak sfc wave move along
the boundary over the next few hours until midnight to 2 am, so
we maintained some likely PoPs before going to scattered the
rest of the night for the majority of the area. Temps continue
to be stagnant and slow rising, except over the higher terrain
to the south and east of the Capital Region with the warmest
readings over the southern Taconics and southeast Catskills in
the NYS mesonet.
Overall, temps continue to be cool with the dank conditions
with 30s to lower 40s in the valley areas and from the Mohawk
Valley/Capital Region northward based on the NY mesonet and 30s
and lower 40s across the Berkshires and southern VT.
Tannersville has reached 53F and Copake 49F this hours. Locations
to the north of I-90 will continue to rise slowly into the mid
to upper 30s. Locations along and to the south closer to the
boundary or on the south side will be in the upper 30s to lower
50s. The boundary likely will stall near the I-90 corridor.
Patchy fog was expanded across the area through day break in the
damp air mass. Rainfall amounts have been in the tenth to half
inch range in the NYS mesonet and METAR observations with the
higher amounts south and west of the Capital District.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
At the start of Wednesday, our area will be under broad
southwest flow aloft, with a digging trough to the west and
ridging just off the eastern seaboard. There should be a break
in the precip for Wednesday morning into the start of Wednesday
afternoon, although there still will be plenty of clouds around.
Temps will vary considerably across the area, depending on just
where the boundary remains stalled. Model guidance has been
having issues with the exact placement and this has been showing
large variations in the potential for temps on Wednesday.
Northern areas will probably remain rather chilly in the 30s,
while far southern areas should be mild, with highs well into
the 50s. The middle area (including the Capital Region) is the
highest uncertainty. For now, it looks like the day may start
somewhat mild in the 40s, but temps will likely be falling in
the afternoon, as the boundary starts shifting back southward.
Another round of steady precip looks to occur for Wednesday
evening into Wednesday night, as the next wave of low pressure
moving along the stalled boundary heads towards the area from
the southwest. All areas should be starting out seeing some
steady plain rainfall on Wed evening. However, northern areas
will be starting to shift to freezing rain and possibly some
sleet through the overnight, as the low-level cold air bleeds
southward into the area from the North Country. This will be
most likely in the upper Hudson Valley (from Indian Lake and
North Creek southward towards Hadley) and in the Lake
George/Glens Falls area, as cold air drains down the Champlain
Valley. Also, parts of southern VT (especially just along and
east of the Greens) will start to see a threat for some mixed
precip towards late Wednesday night as well. The steadiest
precip should end towards daybreak Thursday, but any lingering
precip may be wintry for early Thursday for the rest of the
Adirondacks, southern VT and into the northern Berkshires as
well. A light accretion of flat ice (mainly a trace to 0.25 of
an inch) is expected for these northern and eastern areas, with
the highest totals in northern Warren and northeastern Hamilton
Counties NY. Elsewhere, the precip will stay just rain, but
temps will be falling for Wed evening into Wednesday night. Lows
will be in the 30s for most spots, although far southern areas
may only fall into the low 40s.
The steadiest precip will be done on Thursday morning, however,
some additional showers can`t be ruled out into the day on
Thursday, as the remnant occluded front decays over the area
and the departing surface low strengthens slightly as it exits
off the New England Seacoast. P-type will likely be variable,
with just rain showers for valley areas, but a wintry mix,
including snow for the high terrain. The highest coverage of
precip on Thursday looks to be across western New England, but
even there, the additional amounts look very light, with under
an inch of snow/sleet and just a trace of ice. Rainfall amounts
looks light too and most of the time will just be dry. Most
areas will be seeing steady temps in the 30s, although southern
areas will still be topping out in the low 40s, but clouds
remaining in place through the day.
A few lingering rain and showers will still be around on
Thursday night as the upper level trough starts to approach. Any
precip looks light and spotty, but it will remain cloudy across
the entire area with temps mainly in the 30s (some upper 20s
across the Adirondacks and Greens).
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Moderate to high confidence in the overall temperature pattern as
forecast models/ensembles continue to suggest a warmer than normal
pattern regime continuing through the long-term period with higher
geopotential heights and a mean H500 flow that`s flat (semi-zonal)
over the region. With average high/low temperatures January 6-10th
in the lower 30s/mid teens, respectively, forecast high temperatures
will be on the order of 5F-10F degrees above normal with values near
the 40F degree mark each day. Meanwhile, low temperatures will be on
the order of 10F-15F degrees above normal with values in the mid 20s
to lower 30s during this period.
As far as precipitation, there`s less certainty due to the large
model spread in the handling of several weak perturbations in a split-
flow regime tracking over the region that could trigger clouds and
precipitation. There still remains quite a bit of uncertainty in the
precise northern/southern stream tracks and magnitude of these weak
impulses.
We start off the long-term period on Friday with a weakening double
barreled low pressure system with the primary low off the New
England Coast and a weakening secondary surface low and associated
upper low approaching the region. Scattered precipitation (mainly
valley rain/mountain snow showers) will be taking place Friday
morning. These showers could continue into the afternoon hours
before waning in coverage and intensity Friday afternoon/evening as
the low departs to our east. The could be some lake effect snow
showers impacting our northwest zones Friday afternoon/evening into
Saturday as the low departs. A 1025-1032 mb Canadian surface high to
our northwest is expected to build into the region on Saturday
bringing dry weather to much of the area. Forecast uncertainty
increases Saturday into Sunday as a vigorous shortwave/developing
low pressure system develops over the Ohio Valley and tracks east.
At this time, most models/ensembles has the aforementioned Canadian
high deflecting the approaching storm system to our south. This
keeps the area precipitation free Saturday evening into Sunday.
Because of the uncertainty in the track of this next storm system,
have just low grade PoPs (20%) over the area Saturday evening into
Sunday. Beyond Sunday, the pattern looks mainly dry. However, will
have to watch for yet another storm system or two (one to our north
attached to the northern stream and another to our south attached to
the southern stream). Some models are projecting/signaling these
disturbances to impact our area Sunday night into early next week
while others keep the area dry. Have kept things dry for now until
things become more apparent.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Through 00z Thursday....MVFR to LIFR conditions due to a combination
of rain, drizzle, low stratus, mist, and/or fog as a warm frontal
boundary stalls over the region is expected to persist through the
entire 00z TAF cycle. As of this update, conditions are ranging
between MVFR at KGFL to LIFR at KPSF with cigs between 300-1800 feet
AGL and visibilities between 3/4 and 8 statute miles. Latest radar
reflectivity shows the first batch of rain showers east of the
Hudson River Valley and pushing east with fragments of light rain
showers or drizzle from the I-87 and points west. The expectation is
that for tonight any rain showers will taper off to drizzle with a
continuation of low stratus and mist/fog. Overnight into Wednesday
morning, a BKN-OVC deck of low stratus with mist/fog will continue
with patches/areas of drizzle. The second batch of rain is expected
to arrive Wednesday afternoon/evening between 20z-24z.
Winds are expected to remain calm through the 00z TAF period. Low
level wind shear could be a problem at KPOU amid the calm surface
winds with winds 2 kft AGL 35-40 kts out of the southwest.
Outlook...
Wednesday Night: High Operational Impact. Definite RA.
Thursday: Moderate Operational Impact. Chance of RA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...SHSN.
Friday: Moderate Operational Impact. Chance of SHRA.
Friday Night: Low Operational Impact. Slight Chance of SHRA.
Saturday: Low Operational Impact. NO SIG WX.
Saturday Night: Low Operational Impact. Slight Chance of SHRA...SHSN.
Sunday: Low Operational Impact. Slight Chance of SHRA...SHSN.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Frugis/Wasula
NEAR TERM...Frugis/Wasula
SHORT TERM...Frugis
LONG TERM...Evbuoma
AVIATION...Evbuoma
Area Forecast Discussion
National Weather Service Binghamton NY
927 PM EST Tue Jan 3 2023
.SYNOPSIS...
A stalled out front across central New York will keep spotty
showers around tonight into Wednesday morning, with a second
bout of steadier rain expected Wednesday afternoon. Unsettled
weather will continue through the remainder of the week, and
some wintry precipitation may return by Friday.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
915 PM Update...
Showers developed across PA since the last update, so PoPs were
increased across NEPA and the Catskills. Some breaks in the rain
showers are present in portions of CNY, especially west of I-81.
Some minor adjustments were made PoPs into the overnight hours,
mainly relying on NBM and past forecast as the CAMs vary from
solution to solution. These showers will continue through the
overnight and eventually move out early Wednesday morning. Some
minor adjustments were needed to hourly temperatures as well to
better match observations.
An SPS was issued earlier for fog in Pike (PA) and Sullivan (NY)
Counties as visibilities had dropped as low as 1/4 mile. That
will be evaluated at the top of the hour if another is needed.
Fog remains present across the region. Latest observations show
that the valley around Elmira has also dropped to 1/4 mile.
Patchy areas of low visibilities will remain possible over the
next few hours. Then there may be some improvements though fog
will remain present.
600 PM Update...
Showers continue to move through the region, though activity is
more isolated across NEPA and the Catskills. With less activity
south of the Southern Tier and not much to the west on the
regional radar mosaic, PoPs were lowered in the southern half of
the region. It seemed like the HRRR has been handling this the
best, so that was blended in with the previous forecast. This
does keep higher PoPs across CNY through the evening, which is
also supported by most of the CAMs. Patchy fog was added for
more areas based on the visibility forecast that is used for the
TAFs. Forecast soundings are saturated in the lower levels
throughout the night. Conditions may improve some once the
showers move out.
Some minor adjustments were needed for the hourly temperatures
as well. Observations in Oneida County are reporting 30s. The
northern portions of the Finger Lakes are also slightly cooler
than forecasted. Conshort and ADJLAV were blended with a little
bit of the NAMNest to get the forecast closer to what the obs
were reporting.
Previous Discussion...
Light Rain showers continue across the area this afternoon with
some moderate showers moving into the Finger Lakes. The warm
front has stalled out over central NY, with upper 40s to low 50s
across the southern Finger Lakes, Southern Tier and NEPA. Low
40s are present across the northern Finger Lakes extending into
the Mohawk Valley and Tug Hill.
Looking at the overall picture, a stacked low is currently
sitting over Nebraska and Iowa, very slowly drifting to the NE.
A shortwave was ejected from the low and pushed into our region
this morning, initiating the rain showers. This shortwave is
slowly exiting our region to the east and south, taking the
strong upper level forcing with it. The warm front will morph
into a quasi-stationary front this evening and into tomorrow,
continuing to sit across central NY. Mid-level winds will flow
almost parallel to this front, allowing for isolated rain
showers to develop across NY tonight. Continued WSW flow through
the overnight hours will keep lows very warm, only dropping a
few degrees from todays highs and almost 30 degrees above normal
south of the front. Mid 40s to low 50s are expected here while
north of the front, upper 30s to low 40s are expected.
A brief lull in the rain showers is expected Wednesday morning
as some drier air moves across the region. Another shortwave and
associated surface low is expected to eject from the parent
stacked low over the upper midwest, bringing another batch of
rain showers Wednesday afternoon through late Wednesday night.
This surface low will move through the Ohio River valley and
into western NY, keeping the CWA in WAA through Wednesday
evening. The stationary front will keep the thermal gradient in
a somewhat similar place as Tuesday. Warmer temperatures are
expected south of the front across the southern Finger Lakes,
Southern Tier and NEPA, with highs in the mid 50s to low 60s.
North of the front, mid 40s are expected.
As the low moves north and east of the region, it will kick the
stationary front east and pull a cold front through the area,
continuing rain shower chances through the overnight hours.
Temperatures will slowly cool Wednesday night from west to east,
with NY areas in the upper 30s to low 40s and NEPA and the
southern Catskills in the mid 40s.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
335 PM update...
Main concerns in the short term are focused on the lingering
rain showers expected Thursday with the potential for some light
freezing rain possible in northern Oneida County Thursday
night...with a transition to a mix of rain and snow during the
day Friday and lingering snow showers Friday night.
Low pressure system rolling east across the Great Lakes will
have a weakly amplifying ridge out ahead of it across the
Northeast that will have a wedge of drier air associated with it
and allow for a period of relatively dry conditions early on
Thursday. The stationary front draped across the northern
counties will lift farther to the north and the warm, dry air
will shift eastward through the day. The southwest flow in the
mid and upper levels should keep the high terrain light
precipitation...in the form of rain...going into the early
evening hours.
Stronger forcing associated with the upper low will arrive
Thursday night and Friday morning in the form of mostly a
rain/snow mix for the low elevation and valley locations, but
generally light snow for areas above roughly 1400 ft. Could see
around a half inch in the hills south of Syracuse and into the
western Catskills. There is a narrow window for some light
freezing rain across northern Oneida County Thu night as the
warm nose aloft is undercut by the cold temperatures coming in
from the west. The probabilities look even less than before, and
confidence is low, so have keep with just a slight chance of
freezing rain.
The cold air makes a stronger push to the east behind the
departing system which will cause a change to all snow by the
late afternoon/evening time frame. A steady west/northwest flow
will set up in the boundary layer and cause some lake effect
snow showers to be generated across central NY through Friday
night. Accumulations at this time look to be fairly light.
Mild temperatures are expected Thursday with highs topping out
in the 40s to around 50. Overnight lows Thu night/Fri morning
will bottom out in the 30s...before recovering into the mid 30s
to near 40 on Friday and then drop back into the upper 20s and
lower 30s Friday night.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
335 PM update...
Positively tilted, weak, low-amplitude upper trough across the
Great Lake into the Ohio Valley will drag slowly eastward across
the Northeast US this weekend and trigger some precipitation
over central NY and ne PA Saturday into Sunday. This system is
expected to produce light snow, mixed with some light rain in
the valleys and low elevation areas during the day Saturday
before the slightly colder air moves in Saturday night and
Sunday...changing lingering rain over to snow.
Boundary layer temperatures will hover around or just above
freezing with a fairly cold layer aloft which will allow for
mostly snow for the region, but potentially melt some snow
around the flakes in areas that see temperatures in the upper
30s and lower 40s. At this time, any light snow accumulations in
the higher elevations should be limited to an inch or less.
Temperatures drop into the 20s to around 30 Saturday night and
only climb into the 30s for most of central NY to near 40 in the
Wyoming Valley in PA Sunday. There may be a weak lake effect
potential that could continue into Monday morning off of Lake
Ontario, but confidence is not there yet, so will keep with
mostly dry weather Sunday night and Monday with temperatures
down into the 20s in the morning and back into the 30s to near
40 Monday afternoon.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
645 PM update...
Rain over ITH/SYR/RME will taper off to spotty showers by 05z.
Steady rain will move in around 17z Wednesday at all sites
continuing through 00z.
All sites will remain MVFR/IFR through 00z Thursday. Rain will
cause IFR vsbys as well as higher terrain at BGM for the
overnight. Cigs will lower into the IFR category this evening at
all sites. Cigs lift to MVFR Wed morning at ELM/AVP then fall
back to IFR when the rain returns. BGM/ITH could have cigs near
airport minimums late tonight.
With a warm front over the area winds are light and will remain
that way. East winds at SYR then south to southeast further
south in NY and southwest at AVP.
Outlook...
Wednesday night...MVFR/IFR restrictions likely.
Thursday and Friday...MVFR and VFR with low chances for rain or
snow showers.
Saturday...Mainly VFR; low chance for lake effect snow showers
and associated restrictions at RME and SYR.
Sunday...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...JTC/MPH
NEAR TERM...BTL/JTC
SHORT TERM...BJT
LONG TERM...BJT
AVIATION...TAC
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
931 PM CST Tue Jan 3 2023
.UPDATE...
Issued at 928 PM CST Tue Jan 3 2023
Have now added the remainder of the southwest into the dense fog
advisory as the western edge of the fog has now started gradually
moving west. High-res guidance indicates this trend should
continue over the next few hours.
UPDATE Issued at 750 PM CST Tue Jan 3 2023
Have added another tier of counties to the Dense Fog Advisory to
the north and east side of the advisory as Rugby and Harvey have
dropped below 1/4 mile, and Carrington has been hanging out at 1/2
mile. A look at the webcam by Medina also looks quite foggy.
UPDATE Issued at 632 PM CST Tue Jan 3 2023
For early evening update about the only change was to spread
widespread fog to the southwest. As mentioned before, the tricky
part is wondering if we need to spread the advisory out, mainly to
the southwest, but so for visibility has been holding up over that
area. Will continue to closely monitor.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 229 PM CST Tue Jan 3 2023
The main forecast issue in the short term period will be the ongoing
dense fog.
Latest satellite imagery shows fog continues to slowly dissipate
this afternoon. However, there are enough sites with low visibility
to continue the Dense Fog Advisory along the Missouri River. Will
cancel northern and eastern portions of the Advisory, as well as
for portions of southwest ND. Fully expect that the current
advisory mainly along the Missouri River will need be expanded,
but exactly when and how much areal extent remains a question.
Will leave that for the evening and overnight shifts.
Surface high pressure is situated over western and central ND and
looks to remain through the short term period. RAP and HRRR guidance
tend to be overdone with stratus/fog during the winter, but since it
has a pretty good handle on the fog with this event, think they are
reasonable with their fog depiction increasing again this evening
and continuing into Wednesday.
The storms system from the central Plains into Minnesota could lift
and bring more clouds into the James River Valley which could help
inhibit fog development here, but otherwise fog can be expected just
about everywhere through Wednesday. Other than the low stratus and
fog, the weather remains pretty quiet. Lows tonight will be mainly
in the single digits to low teens with highs Wednesday in the mid
teens to mid 20s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 229 PM CST Tue Jan 3 2023
Fog concerns continue into the long term period. A warming trend
looks to be in store late in the extended period.
A weak upper level pressure pattern with a weak surface flow remains
to begin the long term forecast period. On Thursday, a weak upper
level wave slides southeast through central and eastern ND, but with
little surface reflection, don`t think this will have much influence
on our weather. After this we continue to see a series of storms
impact the West Coast, with a general high over low upper level
pattern over the central portion of the country. This would be
indicative of a quiet weather pattern, but some potential fly`s in
the ointment being low stratus/fog issues into the weekend. Building
heights and a more progressive flow late in the period may bring
some warmer temperatures our way. However, a large spread remains in
the NBM ensembles so confidence is not overly great at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 632 PM CST Tue Jan 3 2023
Widespread LIFR to IFR ceilings and visibilities are expected to
continue through Wednesday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until noon CST /11 AM MST/ Wednesday for
NDZ009>013-017>023-025-031>037-040>047-050.
&&
$$
UPDATE...JJS
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...JJS
Area Forecast Discussion...Updated
National Weather Service Billings MT
849 PM MST Tue Jan 3 2023
.UPDATE...
Challenging fog forecast for SE MT tonight. High clouds were
moving NW into the area from central plains, while Nighttime
Microphysics showed broken areas of fog over N Rosebud County into
Custer County with some fog or stratus developing over Powder
River County. Some webcams showed dense fog such as Sweeney Creek
and Ingomar...while KMLS visibility was up to 2 1/2SM. Decided to
stay the course and leave the Dense Fog Advisory in place over
Treasure, Custer, Fallon, and Northern Rosebud based on HRRR
guidance. A vort max was nearly stationary over the S. Central
part of the area with some radar echo that was likely just mid
cloud based on nearby obs. Models showed a colder airmass moving
in overnight, while a favorable pressure gradient for gusty winds
remains in place over western areas. Forecast covered temps and
winds well, except the Northeast Bighorns were at/near forecast
lows, so have lowered temps there. Arthur
&&
.DISCUSSION...
Tonight through Wednesday Night...
Fog remains the main issue over the next 24 hours. Visibility of a
quarter mile continues to be reported at Miles City and Forsyth as
of 130pm. Satellite imagery shows fog persisting along the
Yellowstone as well as some other eastern valleys, and web cameras
in northern Rosebud County remain quite foggy. We remain under we
weak flow aloft with light easterly surface winds across our
east. High res models continue to support dense fog across mainly
our northeast from Rosebud to Fallon Counties thru the night. By
Wednesday morning we will begin to advect drier air from the west
and this should erode the fog for good. In the meantime, we have a
dense fog advisory in effect for these areas thru 18z tomorrow.
Satellite imagery shows departing low well to our east (moving
into MN/IA), having undercut a region of high pressure centered
over southern Saskatchewan. Upstream there is a shortwave
approaching the Pacific coast, and a deeper trof further west.
Overall theme is to increase the Pacific flow over the coming
days. This will of course result in a warming trend for us.
Other than some light snow showers over the mountains, the next 36
hours will be dry under slowly building heights. Temps will be
seasonable. Look for highs on Wednesday in the upper 20s and 30s
(coldest east where there remains some snow cover).
Regarding wind, there appears to be a brief opportunity for
Livingston to reach 50 mph gusts tonight into early tomorrow. Mid
level winds do not appear to be strong enough for higher gusts
than that so no need for a wind highlight...but high-profile
traffic on I-90 should take note.
JKL
Thursday through Tuesday...
Very quiet weather will continue into next week. The only
exception to this is a weak shortwave which will bring some light
snow/rain showers Thursday night and Friday. Main forcing tracks
well to our south and latest model trends are drier for our
region. Not much else to say.
Looking across the Pacific we see an enhanced zonal jet across
much of the Ocean, and this is leading to warm air pushing into
all of western North America...a pattern that will change very
little over the next week. There is an occasional weak/splitting
shortwave embedded in the Pacific flow...thus periodic chances of
light snow for our mountains. Otherwise, any chance of precip at
lower elevations will remain quite low thru next Tuesday and
likely beyond. Seasonable temps Thursday will climb to above
normal for the the end of the week...where they will stay for an
extended period of time. Look for highs generally mid 30s to upper
40s this weekend thru the middle of next week. Could see some 50s
in there too.
Looking for a return to something colder & snowier? You`ll have to
wait til the second half of January, at least. There are signs of
a disruption to the Pacific jet by the middle of the month, which
could change the longwave pattern eventually. Stay tuned.
JKL
&&
.AVIATION...
Areas of dense fog and low clouds causing VLIFR/LIFR conditions
will continue across eastern Montana into Wednesday morning. This
will impact KMLS and KBHK. Visibility will drop to a quarter mile
or less at times. VFR conditions are expected in the rest of the
forecast area. Conditions will improve to VFR for the entire
forecast area by Wednesday afternoon as the fog lifts. Archer/TWH
&&
.PRELIMINARY POINT TEMP/POPS...
Wed Thu Fri Sat Sun Mon Tue
-----------------------------------------------------------
BIL 021/037 020/036 026/043 027/045 026/043 027/045 026/045
00/U 00/B 14/W 10/U 00/B 01/B 01/B
LVM 020/034 020/041 029/043 026/043 026/042 027/042 026/045
00/N 01/N 22/J 00/U 01/B 11/B 12/W
HDN 012/035 009/033 018/039 021/041 017/040 019/041 017/042
00/U 00/B 14/W 10/U 00/U 00/B 00/B
MLS 010/028 007/028 013/029 016/034 014/034 016/034 016/034
00/F 00/U 02/J 10/B 00/U 00/B 00/B
4BQ 015/035 012/034 018/036 023/040 019/041 019/041 020/044
00/U 00/U 02/J 10/B 00/U 00/B 00/B
BHK 010/028 009/028 012/028 013/032 017/034 016/033 017/034
00/F 00/U 01/B 00/B 00/U 00/B 00/B
SHR 013/035 012/036 020/038 022/041 018/041 021/041 019/042
00/U 00/B 14/W 20/B 00/U 01/B 00/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Dense Fog Advisory in effect until 11 AM MST Wednesday FOR
ZONES 30>33.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Columbia SC
819 PM EST Tue Jan 3 2023
.SYNOPSIS...
Moisture will increase across the region through Wednesday with
showers along with possible thunderstorms expected ahead of a
cold front. Fair and cooler conditions Thursday into the
weekend behind the cold frontal passage.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
Showers moving into the western portion of the forecast area
this evening. While convection earlier today generated by an
upper shortwave in central GA was strong to severe at times,
with a loss of daytime heating and a more stable airmass in
place over the forecast area, storms have continued to weaken,
denoted by warming cloud tops on IR satellite imagery. While
temperatures across the area have cooled by around 10 degrees
from the high, not expecting much more cooling for the rest of
the night with thick cloud coverage moving in and increasing
winds in the boundary layer out of the SW. Lows generally in the
low 60s tonight. Upper ridging will continue to break down over
the area with some cooling aloft which will lead to at least
weak elevated instability. This should be able to maintain at
least a chance of thunderstorms in the forecast area. GOES GLM
continues to show lightning with the convection moving into the
area from the west but the coverage has decreased significantly.
Still think occasional strikes will be possible through early
tonight. By late tonight into early Wednesday morning, recent
HRRR runs (00z runs of other HiRes models are still coming in
as of writing this) are indicating a break in coverage of
showers and storms. This trend will need to be watched closely
as the earlier this break occurs, the better chance for surface
destabilization ahead of the line storms associated with the
cold front Wednesday.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Cold front will continue to track eastward from western Ga early in
the day. Upper flow pattern at 250mb remains mostly difluent
throughout the day ahead of the front, with stronger jet pushing
towards the cwa by the afternoon. Showers and storms are expected
to be ongoing Wednesday morning along both a prefrontal trough and
along leftover surface boundary from the overnight hours across the
southern portions of the cwa. Convection early in the day may not
be surface based, but more elevated with limited instability due to
weak lapse rates. Better chance for more organized convection should
occur during afternoon just ahead of the main advancing cold front.
There will be a good amount of shear in the lower levels with a
strong 850mb jet moving through. While a widespread severe threat
remains limited, can not completely rule out an isolated severe
storm ahead of the front. With limited instability and stronger
shear, winds or tornadoes continue to be the main concern if a
strong storm takes hold. SPC continues with a Marginal risk for
the majority of the cwa, with a Slight Risk barely nudging into
the western CSRA.
Once the convection and the front move through Wednesday evening,
drier conditions will filter into the cwa overnight and into
Thursday. Temperatures Wednesday are forecast to reach the 70s
again, but may be highly dependent on cloud cover and rainfall.
Lows Wednesday night down to around 50. Cooler air may be a
little slow to move into the area on Thursday, and with a good
amount of sunshine expected, highs should reach the mid to upper
60s in most areas. By Thursday night, cooler air will have
taken over, allowing overnight lows down in the upper 30s to the
lower 40s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Not really a lot of change to the longer term thinking. As the
deeper upper trough moves through the Mid-Atlantic and the
Southeast, drier and cooler air will continue through Saturday
night. Another approaching upper trough will begin to influence the
pattern by Sunday, bringing the next chance for rainfall to the
area. Moisture may still be limited, so pops mainly slight chance
into early next week. Temperatures close to normal through the
period.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
Periodic restrictions expected this evening with showers and
isolated thunderstorms, with more widespread restrictions at all
terminals late tonight into Wednesday morning.
VFR conditions continue for another hour or two at the
Augusta/Columbia terminals, and slightly longer at OGB. BKN-OVC CIGS
are expected to decrease as -SHRA and ISOLD TSRA move into the
region from west to east. Rainfall may be heavy at times with
periodic VSBY restrictions. Confidence in thunder remains too
limited to include in the TAFs. The main area of precip should be
east of the terminals by 04/09-04/11z, with VCSH continuing
thereafter through much of Wednesday morning. Moisture will continue
to rapidly increase with a high likelihood of IFR cigs returning
through mid-morning tomorrow or later, when MVFR cigs are expected
immediately ahead of a cold front. Another line of SHRA/TSRA is then
expected to move through the area early Wednesday afternoon. SFC
winds generally light from the S/SW tonight into Wednesday, with
stronger SW winds 10-15 kts with gusts to 25 kts late Wednesday
morning through the afternoon.
NOTE: The KAGS observation is not available in or unrepresentative
of current conditions at night when an observer is not present. This
has led us to include AMD NOT SKED there and we`ll keep it in there
until further notice due to a communications outage.
EXTENDED AVIATION OUTLOOK...
Showers become more numerous during the day on Wednesday, including
the possibility of thunder through the afternoon. Behind a frontal
passage later Wednesday, conditions should improve and restrictions
are expected to lift at all terminals.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
Area Forecast Discussion
National Weather Service Grand Rapids MI
954 PM EST Tue Jan 3 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 946 PM EST Tue Jan 3 2023
There could be a few stronger storms over the next 2 hours as
instability continues to advect in from the southwest. Deep layer
shear is supportive of organized convection. Model forecasts show
the instability to decrease as it advects in...however given the
current growth of the cells on radar...it appears some of the
storms will contain small hail. A tight frontal zone existed along
I-94. As the 30 knot low level jet crosses this frontal
zone...continued thunderstorm development should occur. So we will
maintain the risk for thunderstorms for the next couple of hours.
UPDATE Issued at 519 PM EST Tue Jan 3 2023
The potential for thunderstorms was increased and brought in
sooner with the forecast update. Radar trends show an area of
showers and thunderstorms over Southern Lake MI tracking
northeast. They appear to have enough momentum to potentially move
into the Muskegon to Grand Rapids area between 700 pm and 800 pm.
Then for the remainder of the night...the steeper mid level lapse
rates advect in from IL and IN during the evening hours. A 30 knot
low level jet also moves into Southern Lower MI. These two
features will help to maintain a risk for at least a few
storms...and increase the potential for small hail.
&&
.DISCUSSION...(This evening through next Tuesday)
Issued at 315 PM EST Tue Jan 3 2023
--Dense Fog Threat Tonight and Wednesday Morning--
Sfc warm front is still located just south of the MI/IN border
but expected to make some northward progress tonight before
becoming a triple point/occlusion overhead on Wednesday. Sfc dew
points are in the upper 50s just south of the front and the
arrival of a juicier air mass and lighter winds/baggier pressure
gradient from the south tonight will set the stage for at least
areas of dense fog, if not widespread.
One limiting factor this evening for dense fog is the potential
for a decent batch of showers (and perhaps even isolated tstms)
to come through, which would temporarily mix out the lower
visibilities. This would be associated with the lobe/spoke of
vorticity currently heading northeast from IL, which also
represents the leading edge of the mid level dry slot. RAP
continues to show 500-800 J/KG MUCapes arriving in srn Lwr MI
after 22Z/5PM ahead of this feature so a clap of thunder is
certainly a possibility.
After passage of the mid level shortwave around 06Z tonight, the
dense fog potential should be on the increase and an advisory may
be needed to cover the Wednesday morning commute period.
Confidence in location/coverage of the densest, most persistent
fog is currently too low to issue a headline. Visibilities are
expected to slowly improve by Noon Wednesday.
--Light Snow/Rain Mix Wednesday Night and Thursday--
As the upper low over Iowa slowly meanders in our direction the
next few days, periodic light precip will persist within moist
cyclonic flow pattern. Colder air aloft arrives from the
west/southwest on Wednesday night which eventually changes the
scattered rain showers over to snow showers or a rain/snow mix.
Minimal travel impacts expected as any snow accumulations should
be under an inch and sfc temps look too marginal to support much
of a freezing rain or drizzle threat.
--Mild/Tranquil Pattern over the Weekend--
The upper low moves away on Friday although upper troughing and
the cold air aloft lingers into Friday night. This could support
some lingering light precip, but surface ridging is shown to
eventually build in over the weekend. Actually it looks like some
sunshine potential exists for Sunday and Monday which has been an
extreme rarity over the last month or so.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 627 PM EST Tue Jan 3 2023
Earlier we updated several TAF sites to add some thunder to the
forecast. With this issuance we expanded the thunder mention and
added a few more hours. One batch of storms was rolling northeast
through KMKG and almost into KGRR. Those will not last long as
they are moving quickly. We should see a break for an hour or
two..but the next round of storms is already developing in IL.
These storms should continue to expand as they track northeastward
into Southwest Lower MI. They will be around for a few hours this
evening before moving away from the TAF sites by midnight.
IFR and lower conditions will prevail for most of time through
18z. After 18z Wednesday...there are some indications that we
could see conditions going to MVFR as slightly drier air advects
in from the west. We did feature an improving trend to the
ceilings and visibilities during this timeframe.
&&
.MARINE...
Issued at 315 PM EST Tue Jan 3 2023
Will cancel the Small Craft Advisory early since stronger east
winds north of the warm front never really materialized.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...MJS
DISCUSSION...Meade
AVIATION...MJS
MARINE...Meade
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
958 PM EST Tue Jan 3 2023
.SYNOPSIS...
Widespread rainfall and possible thunderstorms are expected to
develop from the west late today and persist through Wednesday as a
cold front sweeps east across the region. Drier and cooler
conditions return by the end of the week. Increasing cloud cover and
low precip chances return by the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 935 pm EST: A wide band of showers and embedded thunderstorms
driven by a lead short wave continues to work its way east across
the Upstate and western Piedmont this evening, with the radar mosaic
showing less coverage over the mtns. This appears to be the lull
in the action to which the day shift expected. Precip probs will be
adjusted accordingly. Still a few lightning strikes in the activity
across the eastern zones in a lingering band of weak most-unstable
CAPE of around 250 J/kg. Our severe chances are very low for the
next few hours, but may ramp up from the west and southwest as we
get on toward daybreak Wednesday as suggested by the most recent
run of the RAP showing air mass recovery and destabilization ahead
of the front working its way in from the SW. Temps are in need of
adjustment based on the evolution of the widespread precip.
Otherwise...a deep mid-level vortex is expected to stall over the
upper MS River basin tonight and Wednesday. A vigorous cold front
stretched south of this system along the length of the Mississippi
River. This boundary will make steady progress eastward toward the
southern Appalachians through tonight, driven forward by a pair of
strong short waves rotating through the upper trof, before crossing
the region through Wednesday. After our brief lull into the early
overnight, discrete coverage is expected to pick up through the
morning hours east of the mountains, and a wider upslope and frontal
focus should develop near the southern mountains. Hydro concerns
will ramp up steadily through daybreak, but flooding issues should
be isolated enough to avoid a Flood Watch. Any flooding associated
with training cells will be harder to pin down through Wednesday,
and a Marginal risk of excessive rainfall will be possible just
about anywhere until the front passes.
The approaching cold front will reach the spine of the southern
Appalachians late Wednesday morning and then cross the region
through late day. The 18Z run of the NAM shows a favorable overlap
of 500-1000 J/kg of sfc-based CAPE and deep layer shear on the
order of 45 kt...which is corroborated by the 21Z RAP. Hodographs
elongate in the morning with the passage of a 50+ kt low level
jet, and look...compelling. As we like to say...we`ve done more
with less. The Day 2 Convective Outlook shows Marginal east of
the mtns, but the previous run of the HREF and subsequent HRRR
runs have shown some rotating storms along/S of the I-85 corridor
through the morning and early afternoon, so it might be best to
anticipate a better severe storm risk for Wednesday.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 100 PM EST Tuesday: The trailing cold front associated with
a stacked occluded low over the northern Great Plains and Upper
Great Lakes region will be in the midst of making a full fropa
across the CFWA by the start of the forecast period as any lingering
precip in the eastern zones should come to an end by Thursday
evening. Dry conditions will be in store as surface high pressure
gradually builds in as it slides across the Lower MS Valley and Deep
South through the short-term. Temperatures on Thursday will remain 5-
10 degrees above normal as a downslope component will offset any
post-frontal cooling. With the axis of the stacked low lifting out
of the area Thursday night into Friday, northwest flow will begin to
filter in. Upper forcing from the passing vort lobe on the base of
the lifting upper trough and just enough cold air and low-level
moisture should promote the development of a few NWFS showers along
the TN border in the favorable upslope locations. Accumulations will
be very light, but the overall ingredients don`t support a more
significant event. High pressure remains in control through the end
of the work week as deep layer northwest flow pushes into the area
late Thursday into early Friday. This will support a dropoff in
temperatures by Friday to more seasonal values as weak CAA settles
in.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 230 PM EST Tuesday: The pattern becomes more uncertain in the
extended period. Model guidance currently overlays quasi-zonal flow
aloft over the region with embedded shortwaves traversing within
this regime for much of the forecast period. Sporadic areas of
forcing could lead to mentionable PoPs over the weekend into early
next week as a weak low pressure system develops over the mid-MS
Valley and travels eastward. This will bring on and off chances of
light precip across the area, especially over the High Country.
Thermal profiles are too warm to support anything other than rain
outside of the ridgetops. Good consensus with drier weather being in
store for the D6/D7 time period. Temperatures will generally run
near-normal for much of the period, with some variability due to
precip chances and cloud cover.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Grim aviation weather for the next 12-18
hours with widespread IFR to LIFR ceiling and MVFR/IFR visibility
in waves of rain and embedded thunderstorms. There will be MVFR/VFR
holes in this activity, with still a decent chance for an overnight
lull in the precip activity, but the IFR or worse will prevail. Wind
will be mainly S to SW away from convective storms. Models indicate
another round/wave of convection that will organize to the west
overnight and then move eastward across the fcst area from daybreak
through mid afternoon. The convection will bring an improvement
to IFR and MVFR along with a good chance of thunderstorms that
should affect mainly the Upstate terminals and KCLT. A PROB30 was
employed to indicate a 6 hour time period when the storms are most
likely to cross the region. An isolated severe storm will not be
ruled out. Wind will be gusty from the SW. Rapid improvement will
occur as an effective cold front crosses the region in the mid to
late afternoon. All terminals should become VFR by sunset.
Outlook: VFR with dry conditions return by Thursday and continue
into Saturday. Another moist low pressure system could affect the
region late in the weekend.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...CAC
NEAR TERM...HG/PM
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...PM
Area Forecast Discussion...UPDATED
National Weather Service Hanford CA
444 PM PST Tue Jan 3 2023
.UPDATE...Updated AIR QUALITY ISSUES section.
&&
.SYNOPSIS...Active weather continues for at least several
more days. A break in the rain today will eventually lead to a
strong storm system impacting the area Wednesday morning into
Thursday evening. On Friday, calmer weather is expected before
another low pressure system arrives into the area Saturday.
&&
.DISCUSSION...Calmer weather and warmer temperatures are
prevailing today, before tomorrow’s activity. On Wednesday
morning, a warm frontal surge will bring light to moderate
precipitation into our area with showery conditions continuing
later in the afternoon. From late Wednesday evening into Thursday
a strong (150+ kt at 250 mb) jet will position itself at a
favorable position for some dynamic lifting to be associated with
the second punch. This will result in strong winds across
downslope prone portions of our CWFA.
The 18Z HRRR model indicates high winds in the San Emigdio and
Tehachapi Mountains with sustained winds reaching 40 to 50 mph
and gusts approaching 95 mph. Combined with low visibility,
treacherous travel is a concern at the Grapevine/Tejon Pass. A
High Wind Warning has been issued for this part of the forecast
area between 400 am PST Wed and 400 am PST Thu. In addition,
increased downslope winds are expected along the West Side Hills
and in the south end of the San Joaquin Valley with sustained
winds reaching 20 to 30 mph and gusts approaching 55 mph.
As the cold front approaches on Wednesday night and Thursday
morning, it will bring moderate to heavy precipitation and high
elevation snowfall. A Flood Watch is in effect for the entire
CWFA except the Kern County Deserts and the higher elevations of
the Sierra Nevada from 400 am PST Wednesday until 400 am PST
Friday. With the anticipated rainfall from the incoming system
combined with saturated soil from previous rainstorms, this could
lead to another round of widespread nuisance flooding and the
potential for rock slides. A Winter Storm Warning remains in
effect for the high elevations of the Sierra Nevada. The forecast
include 6 to 18 inches of new snow above 5000 feet and 2 to 4 feet
of new snowfall above 7000 feet.
Another concern with this system is that with post-frontal
unstable airmass over central CA on Thursday afternoon,
thunderstorms will be possible across the San Joaquin Valley,
West Side Hills and Sierra Nevada foothills. The Storm Prediction
Center is showing a marginal risk of severe thunderstorms in the
western half of the San Joaquin Valley and over the West Side
Hills by Thursday afternoon.
A lull in activity is expected for Friday before an approaching
low pressure system affects our region on Saturday. This storm
system is expected to be drastically weaker. Afterward, a
potentially strong storm system will have to be monitored closely
for potential impacts across our area next Monday and Tuesday.
The Climate Prediction Center continues to show chances of above
average precipitation across the entire state of California 6 to
10 days out. This combined with heavy Sierra Nevada snowfall will
lead to a wet first half of January.
&&
.AVIATION...Increasing MVFR conditions with areas of mountain
obscuring IFR conditions will become prevalent across the Sierra
Nevada and adjacent foothills by 15Z Wed. Obscuring IFR and
possibly LIFR conditions in low clouds and precipitation will be
focused for the Sierra Nevada and Tehachapi Mountains and the
adjacent foothills and valley facing slopes. Areas of MVFR in rain
and low clouds over the San Joaquin Valley after 12Z Wed.
Elsewhere, VFR conditions will prevail across the central CA
interior for the next 24 hours.
&&
.AIR QUALITY ISSUES...On Wednesday January 4 2023,Fireplace/Wood
Stove Burning Status is: No Burning Unless Registered in Fresno
and Kern Counties. Burning Discouraged in Kings, Madera, Merced,
and Tulare Counties, and Kern (Greater Frazier Park Area) and
Sequoia National Park and Forest.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
and/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 4 AM PST Wednesday through late Thursday night
for CAZ300>327-329>336-338.
Wind Advisory from 4 AM Wednesday to 4 AM PST Thursday for
CAZ300-304-308-313-316.
Winter Storm Warning from 7 AM Wednesday to 4 AM PST Friday for
CAZ323-326>330.
High Wind Warning from 4 AM Wednesday to 4 AM PST Thursday for
CAZ334>336.
&&
$$
public...Chamberlain
grids/aviation/fire wx...DAS
pio/idss...BS
weather.gov/hanford
Area Forecast Discussion
National Weather Service Lincoln IL
823 PM CST Tue Jan 3 2023
.SYNOPSIS...
Issued at 243 PM CST Tue Jan 3 2023
Scattered showers and thunderstorms are possible west of I-55
through Tuesday evening. A few storms could be strong to severe.
It will be much cooler on Wednesday, with high temperatures
returning to near normal, in the upper 30s. Scattered flurries or
light snow will be possible Wednesday afternoon through Thursday,
primarily north of I-74.
&&
.UPDATE...
Issued at 822 PM CST Tue Jan 3 2023
At 8pm this evening, a cold front was located roughly just east of
the I-55 corridor and will continue east across the remainder of
central and east central Illinois clearing the forecast area by 1
or 2 AM. A few spotty showers remain ahead of the front, most
notably over northern Champaign and Vermilion Counties, but also
an isolated cell southwest of Effingham. These should diminish or
move out of the area over the next couple hours with dry
conditions expected the remainder of the night. Based on earlier
reports, it`s possible that 5 tornadoes touched down during storms
this afternoon/evening and will be sending out a survey crew
Wednesday morning to confirm.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 243 PM CST Tue Jan 3 2023
As of 2PM, visible satellite imagery showed mostly sunny skies
across E MO and west-central IL, aside from diurnal cumulus.
Records are falling across the area as temperatures soar into the
mid-60s. Areas along and east of I-57 were still overcast, but the
corridor of clear skies should pivot eastward this afternoon
resulting in at least some sun.
A dewpoint gradient is present across the CWA, with dewpoints
decreasing with westward extent from I-55. Despite the latest RAP
mesoanalysis showing 1000 J/kg of uncapped CAPE, vis satellite
shows limited vertical extent to any of the diurnal cumulus across
our area at the moment. Updrafts look a little more vigorous
across SW IL as of 230PM. With sunshine prevailing and a slight
increase in upper level forcing expected this afternoon, still
anticipate shower/t- storm development within an hour or two.
Much of the thinking regarding hazards has not changed since the
early morning and mid-morning AFDs. There is a low, but non-zero,
tornado potential. RAP analysis is in line with forecast
soundings in showing 100+ J/kg of 0-3km CAPE in the vicinity of
the sfc boundary, but the low-level wind profile appears largely
unidirectional, with the KILX VWP hodograph showing no curvature
and RAP analysis showing less than 100 m2/s2 SRH in the lowest
kilometer. Small hail and damaging wind gusts look like more
relevant concerns with any stronger updrafts this afternoon.
Showers and storms may linger east of I-57 through 9 PM, then the
rest of the night will be dry with cooling temperatures overnight.
By Wed morning, the upper low will be positioned near the MN/IA
border. A much cooler airmass will advect into the area behind the
cold front, with 850mb temps falling to around -5 degC, a drop of
nearly 15 degC in 24 hours. Expecting highs to only be in the 30s
west of I-57, and while that`s right in line with typical temps
for early Jan it will feel much cooler after the record setting warmth
on Tues. With sfc winds of 10-15 mph, it will feel even cooler,
with wind chills in the 20s through the day. It will be mostly
cloudy on Wed. Steep low-level lapse rates and a shallow layer of
instability atop the boundary layer could result in scattered
flurries or light snow, primarily north of I-74 beginning Wed
afternoon.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 243 PM CST Tue Jan 3 2023
Main forecast highlights through early next week include:
1) Cloudy and seasonable on Thurs, with isolated flurries or light
snow across the northern half of the area.
2) The next chance for measurable precip is Saturday, in the form
of a mix of rain and snow.
3) Dry with slightly above normal temps Sun into early next week.
Thurs looks quite similar to Wed: cloudy with seasonable temps,
modest westerly winds, and a chance for flurries or light snow
across the northern half of the CWA as the upper low swings
through N IL. By Fri, the upper low will have shifted off to the
NE, and a sfc high pressure ridge builds into the Midwest,
resulting in lighter winds and perhaps some breaks in the clouds.
By Fri night, the next shortwave of interest is expected to be
emerging over the central Plains. An associated sfc low develops
and leads to precip across central IL on Sat. Rain and snow both
appear possible at this time, though it`s somewhat difficult to
discern between the two as both sfc temps and wet-bulb temps are
currently forecast to be in the mid-30s, and the specific values
will likely change depending on the exact track of the sfc low.
Forecast soundings do not show much signal for mixed precip at
this time, except for perhaps a chance of freezing rain/drizzle as
precip winds down and cloud ice is lost. But confidence in that
occurring is not high, so kept any mention of freezing rain out of
the forecast. Ensemble members suggest QPF amounts of a few
tenths are possible with this system, but there is currently not a
signal for anything more than minor snow accumulations, if that.
Behind that system, sfc high pressure builds in and should result
in several days of dry weather across central IL, along with
slightly above normal temps into early next week. Models show a
disturbance moving through the southern Plains and mid-MS Valley
Sun night into early next week, but current indications are that
it should track far enough south to keep precip away from our CWA.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 518 PM CST Tue Jan 3 2023
A cold front is sweeping across central Illinois this evening.
Scattered showers and storms are occurring near the front and will
end as southerly winds veer to westerly behind the front. West
winds will gust to around 20 kt behind the front and conditions
should return to VFR for several hours before cold air
stratocumulus develops resulting in MVFR ceilings that last the
remainder of the period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Deubelbeiss
SYNOPSIS...Erwin
SHORT TERM...Erwin
LONG TERM...Erwin
AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Indianapolis IN
957 PM EST Tue Jan 3 2023
.Forecast Update...
Issued at 957 PM EST Tue Jan 3 2023
Thunderstorm activity in Illinois has diminished quite a bit in the
past couple of hours. However, there are still some showers and
embedded thundershowers along the front. Some activity is starting
to pop up in southern Illinois and western Kentucky, and this may
propagate downstream into Indiana as the night goes on. Trimmed PoPs
in the immediate near term and confined them to the timing of the
cold front, as any showers or storms will be along this boundary.
Latest HRRR and RAP runs tend to agree with this idea. SPC
mesoanalysis shows a lingering pocket of up to 500J/Kg MLCAPE across
our western and northwestern counties. Therefore kept a mention of
thunder for a few more hours until instability wanes.
Elsewhere in the forecast, made minor adjustments to wind and
temperature to reflect latest observations. Otherwise, forecast
remains on track.
&&
.Short Term...(This evening through Wednesday)
Issued at 259 PM EST Tue Jan 3 2023
* Scattered showers and a few thunderstorms possible late
today/tonight. Isolated severe cannot be ruled out mainly west.
* Warm rest of today and tonight, temperatures falling Wednesday in
wake of the cold front.
Currently across the larger region, an area of low pressure is
located across western Iowa, with a stationary front extending
eastward across northern Illinois and Indiana, and a cold front
extending southward just west of the Mississippi Valley.
Much of the warm sector has remained socked in with low stratus
today, which has limited insolation and allowed advection to
dominate warming processes today. There is a clear slot just ahead
of the front with an area of low level convergence along the
backside of the stratus deck. Some very modest instability has
developed in this area, and CAMs have pretty consistently developed
some scattered convection in this area late this afternoon into
early evening. They have backed the timing up slightly which appears
reasonable given the earlier more aggressive runs and the minimal
initiation thus far.
Do expect a few showers and perhaps isolated-widely scattered
thunderstorms to develop over the next couple of hours in this area
and move toward central Indiana late today into this evening. Deep
layer shear is ample, which may allow a few updrafts to at least
minimally organize. Timing of arrival is not ideal, and activity
should be steadily weakening as it moves into the area, but an
isolated severe storm cannot be ruled out entirely before about 9-10
PM in the western portions of the area. Strong wind gusts and
perhaps some hail would be the primary threats, but this remains
highly conditional.
Any precip will continue to spread eastward ahead of the front
overnight as the boundary moves into the area. Thunder threat should
wane rapidly after dark, ending by midnight. Any lingering rain will
come to an end by around daybreak Wednesday as the front exits.
Temperatures will remain very warm for the time of year ahead of the
boundary, with overnight lows likely to also be near Wednesday`s
maximums. Temperatures will steadily drop through the day on
Wednesday as cold advection ramps up and have made sure grids
reflect this.
Wind gusts on Wednesday in the wake of the front can be expected in
the 20KT range out of the west/southwest.
&&
.Long Term...(Wednesday night through Tuesday)
Issued at 259 PM EST Tue Jan 3 2023
* Seasonable temperatures in the 30s and 40s
* Multiple chances for wintry precipitation through the weekend
.Thursday and Friday...
*Chance for snow showers Thursday*
Long term period begins with a deep upper trough in place over the
southern Great Lakes with multiple waves rotating around it through
Indiana. Strong vort max pivots into the northern half of Indiana
Thursday afternoon resulting PVA ahead of it and sufficient lift for
precipitation. Forecast soundings show a deep saturated layer around
3-5 km thick through the DGZ with sufficient frontogenetical forcing
for snow shower development Thursday afternoon. Guidance tends to
perform poorly in these scenarios, therefore deviating from the NBM
and adding "scattered PoP" wording to the forecast. Any
accumulations would likely be light and since snow showers would be
scattered in nature. So do not expect a widespread accumulating snow
event..more like nuisance snow showers. Steep low level lapse rates
under a cold air advection regime may also allow for gusty winds to
20-25mph to mix down to the surface, especially under any shower
activity. So bumped up gusts during the daytime hours Thu and Fri to
near NBM 90th percentile to account for higher gust potential.
Upper level convergence on the backside of the departing upper low
in addition to surface high pressure moving in from the south and
west will promote subsidence and drying of the atmosphere into
Friday. Despite slowly moderating temperatures aloft, still
expecting highs to remain cool in the mid 30s to low 40s with the
most sunshine to occur across south and western portions of the
state.
.Next Weekend Into Early Next Week...
*Another chance for wintry precipitation*
Towards next weekend, southern branch of the jet stream becomes
active with a 130kt jet pushing into the Ohio Valley and stretching
southwestward toward Baja California and the Pacific Ocean. Leeside
troughing off the Rockies in combination with the left exit region
of the upper jet will result in surface cyclogenesis along the Front
Range Friday. Guidance shows the low tracking eastward as the exit
region of the jet enters the Ohio Valley. Weak high pressure and a
somewhat colder airmass remain just to the north of this low. Due to
a weaker thermal gradient and the low forming on the right exit
region of a relatively zonal jet, not expecting rapid
intensification of this low. With a sufficient moisture fetch from
the Pacific Ocean and a weak LLJ developing ahead of the low
bringing up moisture from the Gulf, expect precipitation to break
out across the region Saturday. This set up is typically favorable
for a winter precipitation event across the Ohio Valley as a weaker
low would keep warmer air to the south and colder air locked in at
the surface. Latest forecast soundings do show an interesting set up
as colder air remains at the surface Saturday and slightly warmer
air moves in aloft. With guidance showing the track of the low right
through Kentucky, just south of the area, this could leave to a
potential wintry event for Central Indiana. Track of the surface low
is key in determining exact impacts from this system. With the
surface low being weak, fully expect there to be run to run waffling
of the exact track of it. Therefore, confidence remains low on the
forecast for Saturday. However, no matter the exact track, a
conceptual model of this event leads us to believe a wintry event is
possible somewhere in the Ohio Valley and Great Lakes region this
weekend. Will be monitoring this closely as the potential is there
for mixed precipitation.
Looking toward next weekend, broad upper ridging should prevail over
interior Canada, blocking cold air intrusions from diving south
across the region. Surface high pressure along the eastern side of
the upper ridge would likely set-up near the Great Lakes, although
guidance is suggesting any such ridging would be rather weak. Longer
range guidance keeps high pressure over the Great Lakes region and
NE CONUS Sunday through much of next week. Other than the chance for
precipitation Saturday, the rest of the weekend and into next week
appear dry and cool.
&&
.Aviation...(00Z TAF Issuance)
Issued at 637 PM EST Tue Jan 3 2023
Impacts:
* Widespread MVFR ceilings this evening.
* Showers and a few thunderstorms possible this evening.
* MVFR ceilings return tomorrow.
Discussion:
MVFR ceilings are present across Indiana this evening, and these
ceilings should persist into the night. A brief period of low-end
MVFR ceilings near 1000ft are possible as a cold front and
associated rain showers pass through. A few isolated thunderstorms
are possible as well, but with an expected weakening trend of
convection currently in Illinois, thunder wasn`t included in the
TAFs. Ceilings may lift out of MVFR territory into VFR for a few
hours after the front passes by and drier air moves in.
Southerly winds will veer and become more west-southwesterly as the
front swings through. Speeds will generally remain in the 5-10kt
range, with some gusts to 20kt possible after sunrise tomorrow.
Behind the front, a cooler air mass with widespread low stratus will
move in. Expect ceilings to lower to between 2000 to 2500ft during
the day tomorrow. These MVFR ceilings should persist to the end of
the TAF period and beyond as an occluded low pressure system passes
overhead.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Eckhoff
Short Term...Nield
Long Term...CM
Aviation...Eckhoff
Area Forecast Discussion
National Weather Service Lake Charles LA
853 PM CST Tue Jan 3 2023
...New UPDATE...
.UPDATE...
Issued at 851 PM CST Tue Jan 3 2023
A cold front is roughly along a Opelousas to Grand Chenier line
and continues to gradually move east. A drier and more stable air
mass is filtering in behind the boundary decreasing rain chances.
This is in line with the previous forecast and no changes are
needed at this time.
&&
.SHORT TERM...
(Tonight through Thursday night)
Issued at 305 PM CST Tue Jan 3 2023
The storm system continues to take its sweet time moving across
the region this afternoon, so the threat for showers/storms
continue from roughly Lake Charles to Alexandria east. While the
severe threat is steadily dropping, we still cannot rule out a
brief strong or severe thunderstorm. Best chance will be across
the far eastern third of the CWA.
Latest HRRR guidance suggests the frontal system and
showers/storms will have exited the entire CWA by 06Z tonight.
Once the front moves through, expect gradual clearing. Fog
development looks limited tonight and any fog should be patchy at
best. The fog would be confined to along the coast from Grand
Chenier east and from areas around New Iberia south and east.
Wednesday and Thursday are shaping up to be pretty nice days.
Temperatures will generally be around 70 degrees give or take,
with mostly sunny skies. Thursday will be a little cooler, but
highs still in the middle to upper 60s under mostly sunny skies.
&&
.LONG TERM...
(Friday through next Monday)
Issued at 305 PM CST Tue Jan 3 2023
Warm and dry conditions are expected on Friday as the region remains
beneath modest ridging over the southern plains and a surface high
centered east of the area. Moisture will increase over the area
Friday night into Saturday as the ridge axis aloft translates east
in advance of the a weak shortwave crossing the southern Rockies.
Surface low pressure over OK will lift northeast, pulling a cold
front into the region. Increasing ascent ahead of the system will
improve rain chances Saturday, mainly across the western half of the
area, with the best chances areawide by Saturday night into Sunday
as the front slides into the region. Forecast soundings show modest
CAPE, generally below 1000 J/kg, but sufficient for thunder
development in some of the convection. Conditions overall look too
limited for any organized or severe storms but this will continue to
be monitored over the coming days.
High pressure building behind the front should help to nudge the
boundary offshore by Sunday night, although some overrunning
moisture will likely keep clouds and low PoPs over the area until at
least Monday. Rain chances should taper off after Monday.
However, there is still quite a bit of variability in model
solutions toward the end of the long term period, so forecast
confidence for the Day 7 and 8 time periods remains low.
A warm advection pattern will become established on Friday as
southerly winds develop with the surface high to the east. This will
allow high temperatures to climb to about 5 to 10 degrees above
normal, with maximums in the upper 60s to lower 70s. Temperatures
will be even warmer on Saturday with highs into the lower to middle
70s. Temperatures will remain above normal Saturday night, but the
passage of the front on Sunday will usher in a slightly cooler
airmass and more seasonable temperatures for early next week.&&
.AVIATION...
(00Z TAFS)
Issued at 305 PM CST Tue Jan 3 2023
VFR/MVFR at most TAF sites this afternoon, with the exception of
KARA seeing IFR due to low CIGs. KARA should lift out of IFR
through the evening.
While the threat for showers/storms are lowering by the hour,
eastern TAF sites cannot rule out a brief storm/shower. The
activity could briefly lower any TAF site down to IFR in heavy
rain.
The area will clear from west to east with VFR expected at all
TAF sites by late evening or in the early morning hours. The
signal for FG looks limited, but cannot rule out patchy FG along
the coast and over by lower Acadiana.
&&
.AVIATION...
(00Z TAFS)
Issued at 305 PM CST Tue Jan 3 2023
VFR/MVFR at most TAF sites this afternoon, with the exception of
KARA seeing IFR due to low CIGs. KARA should lift out of IFR
through the evening.
While the threat for showers/storms are lowering by the hour,
eastern TAF sites cannot rule out a brief storm/shower. The
activity could briefly lower any TAF site down to IFR in heavy
rain.
The area will clear from west to east with VFR expected at all
TAF sites by late evening or in the early morning hours. The
signal for FG looks limited, but cannot rule out patchy FG along
the coast and over by lower Acadiana.
&&
.MARINE...
Issued at 305 PM CST Tue Jan 3 2023
Winds over the waters are diminishing and seas subsiding, thus the
Small Craft ADV was allowed to expire at Noon today. There remains
a few showers/storms over the waters and this will persist
through the rest of the day and perhaps into the evening hours as
the frontal system is slow to exit the region. While the storms
have been marginal, cannot rule out the occasional Special Marine
Warning.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 51 73 43 66 / 10 0 0 0
LCH 51 71 45 67 / 10 0 0 0
LFT 55 74 47 68 / 40 0 0 0
BPT 50 73 46 69 / 0 0 0 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
SHORT TERM...05
LONG TERM....24
AVIATION...78
Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
1049 PM EST Tue Jan 3 2023
.SYNOPSIS...
A warm front will slowly push northward tonight. A cold front
will approach from the west Wednesday before slowly passing
through Wednesday night into Thursday. Temperatures remain
above normal through Thursday with slightly cooler air following
behind the cold front. More seasonable conditions are expected
into the weekend. A weak low pressure system may impact the
region later in the weekend as well.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Surface warm front remains wedged into the Potomac Valley west
of the Blue Ridge and across northeast Maryland this evening,
where temperatures remain in the 50s with minor visibility
restrictions thanks to saturated low levels. Elsewhere
temperatures remain in the mid 60s with a steady south wind.
A weak shortwave and jet streak aloft are passing through this
evening. Lack of low level forcing and moisture east of the
mountains is causing most of the precipitation to evaporate, but
a few showers or sprinkles could occur through the early
overnight hours. Some guidance indicates fog may form late
tonight near the Chesapeake as humid air moves over the cooler
waters.
Very mild temperatures continue tonight with lows well into the
50s. The current forecast would bring overnight lows to near
current daily records.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Actually think much of the area stays dry on Wednesday morning.
Recent trends in guidance really make it hard to have any POPs
in the forecast before around noon or so. A gusty southerly flow
will pump very warm and moist air into the region Wednesday
ahead of the line of showers and storms expected during the
afternoon. We could see highs hit the low 70s tomorrow during
the early afternoon hours with dew points perhaps in to the low
60s. This could lead to at least some small amounts of CAPE
ahead of the line, which could mean a few rumbles of thunder. Do
think the severe threat is pretty limited though, as the best
forcing comes in well behind the line of showers and storms.
However, could see some gusty winds with the showers given the
50-60 knots of available wind shear. Just don`t see it being
enough to get severe storms in our area, but can`t rule out some
Special Marine Warnings over the waters. Lightning production
may be quite limited as any convection would be low-topped in
nature. Will maintain a slight chance for thunderstorms through
late in the evening as the cold front does not arrive until the
overnight hours. High-resolution models continue to vary in
their depictions of the event. Several models keep us dry, while
the 12z NAMNest brings a broken line of storms through the
whole CWA. Meanwhile, the HRRR keeps activity south of DC, where
instability is likely to be the highest.
With decreasing temperatures aloft with the cold front, some
drop off in temperatures are expected at night and into
Thursday. Westerly flow in the column will offset some of the
cold advection given a downsloping regime. Forecast soundings
show decent mixing in the lowest 100-150 mb. Based on 850-mb
temperatures around 0C, this would favor high temperatures in
the mid 50s to low 60s. A few showers are possible early on near
the Chesapeake Bay. With the front racing ahead of the main
upper trough.
Some rain/snow mix is possible along the Allegheny Front on
Thursday night which may cause light accumulations on untreated
surfaces. Overnight lows fall into the 30s to low 40s with
mid/upper 20s along the Alleghenies.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
On Friday, surface low pressure will be located to the northeast as
high pressure builds into the area behind an exiting cold front.
Lingering moisture wrapping around the low in New England may bring
precipitation to Alleghenies. Given the expected temperatures in the
low 30s, upslope light snow may be possible Friday morning, as well
as Saturday morning.
Guidance is in good agreement showing a shortwave trough moving
eastward out of the Plains on Saturday, but details regarding this
feature are less certain. The GFS and ECMWF are in good agreement
bringing a surface low eastward toward the region with associated
precipitation moving into the area late Saturday into Sunday. The
Canadian is slower with the feature, not impacting the area
until late Sunday into Monday, and takes it more north. As of
now, most of the precipitation, is expected along and west of
the Blue Ridge, though some light showers may spread east. Any
wintry precipitation should also be restricted to along and west
of the Blue Ridge.
Temperatures will still be slightly above normal through the period,
with high temperatures hovering in the 30s to 40s, and lows in the
the 20s to 30s.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
Warm front remains near MRB and MTN this evening but should inch
to the north tonight. That would allow MVFR vsby at MRB to
improve, but confidence isn`t too high given the current
persistence. Areas of MVFR ceilings also moved across CHO, but
current thinking is primarily VFR should occur overnight behind
a departing disturbance. Southerly winds could gust up to 20 to
25 knots at times through the evening. Some guidance indicates
fog may develop near the Chesapeake toward dawn as humid air
moves over cooler waters. For now have introduced a period of
MVFR at BWI/MTN.
On Wednesday, some showers will impact the region which may lead
to some restrictions at the terminals. A non-zero thunderstorm
threat exists as well, especially for the southern TAF sites
like KCHO. Gusty, low-topped showers are possible through
Wednesday night as the cold front treks through. Otherwise, most
guidance does indicate MVFR to IFR ceilings through a large
portion of the day. Can`t rule out LIFR if we end up in a more
stable/stratiform rain event.
Winds quickly shift to northwesterly by Wednesday evening in
the wake of this frontal passage. Shower chances are pretty low
as much drier air begins to move into the region.
VFR conditions are expected Friday and Saturday. Winds out of the
W/NW will likely be gusty with an exiting upper trough, with gusts
around 15-20 kt. Winds should diminish Friday night. Some
precipitation may approach western terminals Saturday evening.
&&
.MARINE...
Southerly winds are resulting in SCA conditions across much of
the waters this evening. These winds should gradually diminish
overnight as low level stability develops. A few gusts near
criteria may continue into Wednesday, but confidence is not high
enough to extend the advisory. By Wednesday evening, SCAs may
be needed once again, although there doesn`t appear to be an
exceptionally strong push of winds with a relatively weak cold
front. Additionally Wednesday afternoon, some gusty low-topped
showers are possible ahead of a cold front. A Special Marine
Warning or two is not out of the question for portions of the
waters, especially over the lower Potomac and Bay zones.
Winds shift to northwesterly on Thursday with gusts quickly
falling below SCA criteria.
Winds out of the W/NW may approach SCA criteria for portions of the
waters Friday afternoon. Winds should diminish overnight with sub-
SCA conditions expected on Saturday.
&&
.TIDES/COASTAL FLOODING...
Tidal levels have been rising today ahead of an approaching
cold front. Anomalies are expected to further rise through
before the cold front tracks through on Wednesday evening. A few
locations are forecast to hit Action stage.
&&
.CLIMATE...
The following record high temperatures were set today (Jan 3):
DCA: 69 (68, 2004/2000)
IAD: 69 (68, 2000)
BWI: 69 (68, 2000)
Continued warmth through Wednesday may lead to some daily
records across the region, both for high temperatures and warm
overnight lows.
*Wednesday January High Temperature*
DCA: 73 (1997)
IAD: 74 (1997)
BWI: 70 (2000)
MRB: 75 (1997)
*Wednesday January 4 High Minimum Temperature*
DCA: 60 (1950)
IAD: 51 (1997)
BWI: 61 (1950)
MRB: 54 (1997)
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until midnight EST tonight for ANZ530-531-
535-536-538-539.
Small Craft Advisory until 6 AM EST Wednesday for ANZ532>534-
537-540>543.
&&
$$
SYNOPSIS...CJL
NEAR TERM...ADS/CJL
SHORT TERM...CJL
LONG TERM...CAS
AVIATION...ADS/CJL/CAS
MARINE...ADS/CJL/CAS
TIDES/COASTAL FLOODING...LWX
CLIMATE...LWX
Area Forecast Discussion
National Weather Service Morristown TN
933 PM EST Tue Jan 3 2023
...New UPDATE...
.UPDATE...
Issued at 918 PM EST Tue Jan 3 2023
We`re in a lull between rounds of showers and thunderstorms
tonight into early Wednesday morning. High resolution CAMs are
coming into better agreement that a second round of strong
convection will move into southeast Tennessee during the overnight
hours. Sounding profiles would suggest another round of a mainly
wind threat with overnight/early morning storms. However as the
shortwave from the plains begins to approach we could see an
uptick in lower level shear. Dew points in the 60`s are starting
to move into northeast AL and parts of southern TN indicating that
the atmosphere is destabilizing ahead of this next round of
convection. Still think the primary threat will be strong winds up
to around 60mph, but cannot rule out an isolated tornado either.
Highest risk area is southeast TN counties along the AL/GA border.
Secondarily, will extend parts of the wind advisory for the far
southern Appalachian Mountains into the early afternoon on
Wednesday. Previously we had hoped there would be a lull in
observed wind speeds in the mountaintops ahead of the second LLJ
strengthening over northern GA overnight... However there are
still observations in the Smoky mountains recording wind speeds
around 50mph. Lower confidence on hitting advisory criteria winds
overnight into tomorrow as the jet looks to be displaced a bit far
to our south, but enough of the high resolution models are
showing 10m winds gusts over 40 knots that an advisory is
warranted.
&&
.SHORT TERM...
(This evening through Wednesday)
Issued at 221 PM EST Tue Jan 3 2023
Key Messages:
1. Showers and thunderstorms, possibly severe, will affect the
area through the rest of this afternoon.
2. A second round of showers and thunderstorms is expected
Wednesday morning, with the potential for severe storms in SE TN
and SW NC.
3. Strong winds continue this evening in the mountains of East
Tennessee.
The threat of severe thunderstorms with a QLCS will continue for
the next few hours, with the area of highest threat of damaging
wind gusts being in the southern TN Valley and SW NC counties.
Although the Tornado Watch is south of our area, a quick spin-up
along the line cannot be ruled out.
Behind this line, we should have a lull in precip as the
atmosphere will be stabilized. However, a second round of showers
and thunderstorms is expected late tonight and Wednesday morning
in association with the surface frontal passage. Frontogenesis
strengthens as the front moves into Middle TN/AL, which draws
moist and unstable surface air northward. The northward extent of
this instability, and the pattern of convective development across
GA, will determine the severe potential on our area. The HRRR had
been the most bullish model with the northward surge of
instability with previous runs, but has trended southward with the
most recent runs. Other CAMs, such as the FV3 and ARW, develop
more convection in GA with a SW-NE orientation, keeping surface-
based instability well to our south. The NAM and RAP bring SBCAPE
values of 400-700 J/kg just across the GA border between 11-14Z,
with 0-1 km shear values of 30-35 kt. Overall, confidence is low
that the severe threat will reach our area, but if it does, our
southern tier of counties (Hamilton to Clay NC) could have a
threat of damaging winds and tornadoes in the early morning hours.
For most of the area outside the southern-most counties,
convection Wednesday morning will remain elevated, with a lesser
potential for strong/severe storms. However, these will be
efficient rain-producers, with strong upper divergence acting on
anomalously high PW values of 1.3-1.5 inches. If storms
repeatedly track over the same areas, flooding will be a threat.
QG forcing should exit the area between 15-18Z, and dry air will
build in behind the exiting front through the afternoon. With the
main upper trough axis still to our west, decreasing clouds, and
a SW flow through the column, we will remain rather mild on
Wednesday afternoon, with temps in the 60s.
The Wind Advisory will be extended until 10 pm this evening based
on obs showing winds continuing to gust between 30-50 mph in the
mountains and foothills. After that time, the models show the LLJ
quickly diminishing.
&&
.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 221 PM EST Tue Jan 3 2023
A quieter weather pattern is expected for this period, with
temperatures generally close to normal values for early January.
A closed low will be tracking east across the Great Lakes to New
England through Thursday into Friday. As the mid/upper level
trough axis crosses our area, we will have cold advection and
some steepening lapse rates in northern portions of the area.
This could result in some sprinkles/flurries in SW VA and the
mountains Thursday night/Friday morning. Moisture appears too
limited at this time to expect any accumulation.
A weak ridge builds over the area on Friday, which should provide
a dry period through Friday night. Rain chances return on
Saturday as a trough moves across the Plains, and a brief window
of moisture advection from the Gulf opens up ahead of this system.
With models disagreeing on the evolution and timing of this
system, will have just a low to slight chance PoP Saturday and
Sunday. The models continue to diverge regarding a potential
system in the Monday/Tuesday time frame. Will carry a slight
chance PoP for these periods, as shown by the NBM.
&&
.AVIATION...
(00Z TAFS)
Issued at 626 PM EST Tue Jan 3 2023
Rain remains near the KTRI terminal, but should clear out in the
next few hours. Expect most of the overnight hours to remain calm,
before another round of storms in the morning. Some uncertainty on
when the front edge will move in. Have gone with TEMPO VCTS during
the period when strongest storms are expected. Once the storms
move out expect VFR conditions to slowly return during the
daytime.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 62 69 43 57 / 80 70 0 0
Knoxville McGhee Tyson Airport, TN 60 68 41 54 / 70 80 0 0
Oak Ridge, TN 60 67 40 54 / 60 70 0 0
Tri Cities Airport, TN 57 66 40 53 / 80 80 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Wind Advisory until 1 PM EST Wednesday for Blount Smoky
Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains-
Southeast Monroe.
VA...NONE.
&&
$$
SHORT TERM...
LONG TERM....DGS
AVIATION...
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 300 PM CST Tue Jan 3 2023
Key Messages:
- Light snow north of I-80 corridor gradually ending this evening
south to north.
- Dry conditions heading into and through this weekend.
Water vapor imagery this afternoon clearly showing upper low
pressure centered over eastern NE slowly lifting toward the upper
Midwest. Meanwhile, regional 88D was showing bursts of
light/moderate snowfall along/north of I-80 within area of
upglide/steep mid layer lapse rates on the backside of the system.
Per the RAP it appears that adequate omega the rest of this
afternoon and evening via vort lobes rotating down the backside of
the system/pockets of isentropic upglide to support areas of
light snow over the northern CWA. This may equate to an
additional inch of snow by midnight. Current headlines for
advisory expire at 6pm. At this point, do not believe conditions
will be significant enough to warrant extending the advisory into
the evening hours. Late tonight into Wednesday, soundings
suggesting patchy freezing drizzle possible over portions of
northeast NE as well as west-central IA.
Otherwise, it appears per medium range models that a dry forecast is
best fit for the CWA heading into and through next weekend. However,
have noted that models push a system through KS on Saturday and
generate QPF from eastern KS into MO. Will be interesting to see
if models end up shifting its track a bit father north. But again,
feel comfortable enough to go dry all the way through early next
week.
Highs:
Wed - mid 20s/mid 30s
Thu - mid 20/mid 30s
Fri - low 30s/low 40s
Sat - low 20s/low 30s
Sun - upper 20s/mid 30s
Mon - low 30s/low 40s
Tue - low 30s/low 40s
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 521 PM CST Tue Jan 3 2023
Lingering light snow will continue to taper off over the next
couple of hours across northeast Nebraska. Another light burst of
snow could develop over the KOFK area around 12Z Wednesday
morning, otherwise, dry conditions will prevail. VFR conditions
should spread back into KLNK by 18Z Wednesday. MVFR ceilings will
remain over KOMA and KOFK through the period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory until 6 PM CST this evening for NEZ011-
012-015>018-030>034-042>045-050>053-065-066-078.
IA...Winter Weather Advisory until 6 PM CST this evening for IAZ043-
055-056-069.
&&
$$
DISCUSSION...DEE
AVIATION...KG
Area Forecast Discussion
National Weather Service Nashville TN
805 PM CST Tue Jan 3 2023
...New UPDATE...
.UPDATE...
Issued at 753 PM CST Tue Jan 3 2023
The lull before the cold front is currently happening. The HRRR
has the next wave of showers and thunderstorms coming up from the
south after 05Z. This still looks like the eastern 2/3 of the
forecast area /I-65 and east/ will be the area of focus. The good
news is the showers move off the plateau by 15Z with the threat
for severe weather ending around 6 am. The main threat damaging
winds and hail...with a tornado or two possible.
&&
.SHORT TERM...
(This afternoon through Thursday Night)
Issued at 159 PM CST Tue Jan 3 2023
The second of three rounds of potential severe weather has now
exited the cwa, The tornado watch has been cancelled for those last
remaining eastern counties. Conditions have stabilized across the
mid state, but we are looking at the main frontal boundary upstream.
Thus, that 3rd round of potentially severe weather is upcoming this
evening and overnight. SPC still holds a slight risk for the
southeastern two thirds of the mid state through 12Z.
The light rain that covers eastern areas of the mid state will
continue to decrease from west to east. This activity will exit our
Plateau around 5p to 6p or so. then, we will begin to see some
destabilization once again as the aforementioned cold front heads
our way. The good news is that it appears that the forcing along and
ahead of the boundary looks a touch weaker. Furthermore, 850 mb
energy and helicities look weaker as well. Nonetheless, showers and
tstms will increase once again just after 00Z and spread eastward
overnight. Additional qpf does not appear to pose any flood threats.
The system will continue to be a slow mover, with the residual
shower activity finally exiting our Plateau just after 12Z.
Moving on, some sunshine will return on Wednesday, with even more on
Thursday. The replacement airmass looks rather mild still with lows
expected to be in the 30s and highs in the 50s.
&&
.LONG TERM...
(Friday through next Tuesday)
Issued at 159 PM CST Tue Jan 3 2023
In the extended forecast, looking nice into Friday. Then the
southern branch of the jet stream will become active. A frontal
boundary will bring some showers to the area over the weekend. This
feature may stall to our south with some energy forming along the
boundary. Moisture will spread back northward into early next week.
Precip amounts look light and the airmass to our north does not look
all that cold. Thus, just looks like low chances for rainfall for
now. There is quite a bit of uncertainty with the timing of any
precip during the period. So with the light amounts expected, will
just include low pops for a lengthy duration.
For the extended temps, values will run about 5 to 10 degrees above
normal.
&&
.AVIATION...
(00Z TAFS)
Issued at 629 PM CST Tue Jan 3 2023
VFR conditions are expected at BNA/MQY/CKV this evening before
another round of SHRA/TSRA brings MVFR conditions between 05-09Z.
Conditions will improve back to VFR thereafter. At CSV, MVFR/IFR
conditions are expected this evening and overnight as TSRA spread
back over the airport from 06-12Z, followed by a return to VFR on
Wednesday morning. South winds this evening will veer to southwest
overnight then westerly on Wednesday morning, with gusts to 20
knots during the day on Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 57 61 38 53 / 90 10 0 0
Clarksville 52 57 35 51 / 50 0 0 0
Crossville 57 63 36 50 / 90 70 0 0
Columbia 56 61 37 53 / 90 10 0 0
Cookeville 59 63 37 51 / 90 60 0 0
Jamestown 57 63 36 49 / 90 70 0 0
Lawrenceburg 58 62 37 54 / 90 20 0 0
Murfreesboro 58 63 37 53 / 90 30 0 0
Waverly 52 56 35 51 / 60 0 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......12
SHORT TERM...21
LONG TERM....21
AVIATION.....Shamburger
Area Forecast Discussion
National Weather Service Raleigh NC
825 PM EST Tue Jan 3 2023
.SYNOPSIS...
Mild, moist southwesterly flow will increase ahead of a cold front
approaching from the west through tonight. The cold front will move
into the area late Wednesday and Wednesday night. Cooler high
pressure will follow Thursday into the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 825 PM Tuesday...
Radar indicated a continued weakening line of showers (mostly light,
with a few isolated heavier bursts of rain) pushing quickly to the
ESE across the Piedmont. Some light rain or sprinkles continue after
the initial line passes over northwest and west-central NC. Rainfall
amounts have been less than 0.10 for the most part with this line.
The HRRR seems to have a fairly good handle on the current
convective trends. This initial line should continue to weaken as it
moves east toward FAY and RDU. The lack of any instability will keep
any additional activity weak overnight. Expect some showers to be
focused over the southern Piedmont and Sandhills for a few hours
between late evening and the early morning hours.
The thunderstorms over GA will gradually move ESE toward the more
unstable air over central and southern SC (stay to the south of our
southern counties overnight. Additional storms will form along the
cold front over the TN Valley later tonight - and with additional
showers and isolated storms not expected for our region until
Wednesday.
Temperatures: Temperatures were in the lower to mid 60s at mid-
evening. Lows in the upper 50s to lower 60s are still expected. The
forecast lows would tie or break record high minimums at all three
climate sites.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 252 PM Tuesday...
Aloft, the low will meander over the upper MS Valley through Wed
night as the attendant trough and embedded shortwaves migrate
eastward. Gulf and Pacific moisture will increase Wed/Wed night,
with the moist axis moving through central NC Wed eve/night. The
moist axis extending north-northeastward through the Southeast and
mid-Atlantic should shift off the East Coast by Thu. At the surface,
a warm front will lift northward through the area late Tue night/Wed
ahead of the approaching cold front. While the parent low sits over
the upper MS Valley on Wed, a secondary low will break off and
progress eastward through the OH Valley and into the northern mid-
Atlantic/Northeast Wed/Wed night. Meanwhile, the attendant cold
front will progress east of the Appalachians Wed night and move
through central NC thereafter, though timing is uncertain. The best
chance for heavy rain and thunder will be ahead of the front Wed/Wed
night. The timing of the cold front continues to vary between the
medium-range guidance, with fropa timing sometime between late Wed
night and Thu eve.
Temperatures: Although forecast uncertainty remains, there is high
confidence temperatures will be significantly above average and wide
ranging across central NC. Expect highs in the mid 60s NW to upper
70s SE across the Coastal Plain. Lows will ultimately depend on
fropa timing, but for now expect mid 40s NW to mid/upper 50s SE.
Rain and Storms: Instability still appears to be somewhat limited,
generally 500 J/Kg or less, while shear and helicity are still more
robust. There is at least a slight chance for thunder across all of
central NC Wed aft/eve. The SPC has all of central NC in a marginal
risk for severe weather on Wed with the primary threat of isolated
strong to severe storms capable of damaging wind gusts. Rainfall
totals should generally range from half an inch to an inch, though
some locally higher amounts are possible.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 219 PM Tuesday...
The main moisture axis should be well offshore by 12Z Thursday
promoting dry conditions locally as the upper trough lifts into the
northeast. The sfc cold front will slowly move across central NC
during the day on Thursday, clearing cloud cover from west to east
through Thursday night. CAA will lag behind the cold front, allowing
daytime highs on Thursday to still reach well above normal into the
mid to upper 60s. Overnight lows will dip down into the mid to upper
30s.
Flow aloft turns more nearly Friday through Saturday as weak upper
ridging builds across the southeastern US. At the surface, high
pressure from the deep south will ride northeastward along the
southern Appalachians Friday through Saturday promoting dry
conditions across our area. Daytime highs in this period will be a
bit chillier compared to this past week, reaching the mid to upper
50s (near-normal). Calm to light winds coupled with relatively clear
skies Friday night could promote good radiational cooling potential.
Thus, lows are forecast to drop into the upper 20s to lower 30s
Friday night. Increasing clouds Saturday night should negate
decoupling potential, with a bit warmer lows in the upper 30s to
lower 40s expected across our area.
A upper level shortwave is expected to dig into the central
Appalachians region Sunday into Monday. Ensemble guidance is in
pretty good agreement to track a sfc low well north of our area, but
an associated cold front will likely push through Sunday into
Monday. Generally wnwrly flow aloft is expected in this time period
which should keep things relatively dry (the latest GFS has come
more into agreement with the Euro in depicting more zonal flow aloft
and dry conditions Sunday into Monday). However, models are still a
bit split on light rain potential later on Monday through Tuesday.
The GFS develops a second sfc low along the departing cold front
producing light rain late Monday into Tuesday. Conversely, majority
of the most recent Euro runs have kept this period dry (although the
latest 12Z run does produce some precip in this period). Ensemble
wise, median output from the GEFS and EPS are currently depicting
very low probabilities of rainfall for this time period (the CMC is
a bit more enthused, but still only pumps out a few hundreds of an
inch). Given the trends in the ensemble data, decided to keep the
forecast dry at this point for Sunday through Tuesday, but will be
worth re-evaluating as we get closer.
Daytime highs should remain near normal from Sunday through Tuesday
mostly in the mid to upper 50s (perhaps a touch warmer on Sunday; a
touch cooler on Monday). Overnight lows will dip into the mid 30s
over this period as well.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 645 PM Tuesday...
Predominantly VFR conditions are observed across central NC with the
exception of the Triad (GSO/INT) on the edge of a band of low MVFR
ceilings. CIGS are expected to lower into the IFR/LIFR categories
between 08z and 11z tonight and remain Wednesday morning. SW surface
winds should remain between 5-10kts overnight beneath a strong low-
level jet that will be located around 2-3k feet at 30-40kt.
However, pilots should be advised that strong winds will persist at
2kft over all terminals through the TAF period, even strengthening
to 40-50kts out of the southwest Wednesday afternoon. A line of
showers and possibly isolated thunderstorms will move through ahead
of a cold front near the end of the TAF period with the latest
timing for terminals as follows: 16-20z at GSO/INT, 19-22z RDU, 20-
23z FAY/RWI.
Looking beyond 00z Wednesday, MVFR/IFR cigs and vsby will be
possible, especially in the east, Wednesday night into Thursday
morning. VFR conditions return by Thursday.
&&
.CLIMATE...
Record Temperatures for Wednesday January 4:
SITE RECORD MAX RECORD HIGH MINIMUM
GSO 74/2005 57/1950
RDU 76/2005 58/1950
FAY 77/2004 60/2004
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett/KC
NEAR TERM...Badgett/KC
SHORT TERM...KC
LONG TERM...Luchetti
AVIATION...Badgett/Swiggett
CLIMATE...RAH
Area Forecast Discussion
National Weather Service Sacramento CA
317 PM PST Tue Jan 3 2023
.SYNOPSIS...
A weak weather system will continue to bring light rain and
mountain snow tonight. A serices of stronger storms will move
through Wednesday into next week. Strongest storms are expected
Wednesday through Thursday and again over the weekend. Widespread
damainging winds are expected Wednesday afternoon into Thursday.
Heavy precipitation will keep flooding threats elevated and
mountain travel impacts at the forefront for the rest of the week
into the weekend.
&&
.Discussion...
A weak shortwave moving through today and tonight will continue to bring
light precipitation with little to no impacts.
A much stronger storm will spread into the region bringing strong,
damaging winds with heavy rain and mountain snow Wednesday through
Thursday. This is hybrid storm, with a deep Pacific low off the
coast tapping into a very moist Atmospheric River(AR). The
combination of strong dynamic lift and abundant moisture will
bring moderate to heavy rain and heavy mountain snow, especially
Wedensday evening into early Thursday. Elevated flood and recent
burn scar concerns are expected, as well as major mountain travel
impacts in periods of heavy snow are expected.
A strong surface pressure gradient coupled with a strong low level
wind jet (65 kt at 925mb) will bring increasing southerly winds
through the day Wednesday, peaking Wednesday night. Sustained
winds 25 to 35 mph with gusts up to 50 to 60 mph are expected in
the Valley and foothills, so the High Wind Watch has been upgraded
to a Warning from 10 AM PST Wednesday to 4 pm PST Thursday. These
strong winds coupled with saturated ground will likely bring down
trees and cause the potential for widespread power outages. This
will also cause difficult travel for high profile vehicles such as
trucks and RVs. The wind is expected to diminish Thursday
evening.
Precipitation will spread into the area with a warm front early
Wednesday. Snow levels will initially be low early Wednesday,
around 4,000 feet, then rapidly with warmer air advecting in to
around 7,000 feet Wednesday night. Snow levels will drop to around
5,550 feet early Thursday behind a cold front. The majority of
the snow is expected above 5,000 feet, but snow levels associated
with AR`s can be tricky, resulting in either higher or lower snow
levels at times. If driving along roadways between 4000-6000 feet,
be prepared for both heavy rain and/or heavy snowfall. Mountain travel
impacts are likely, with 1 to 3 feet of mountain snow, locally
hight over peaks. Snow may fall at rates up to 3 inches an hour,
bringing very slippry conditions and whiteout conditions, when
combined with winds gusting to 60 to 70 mph. The winds could also
bring down trees, potentially blocking roads and causing power
outages. The Winter Storm Warning continues for elevations above
5,000 feet from 7 am PST Wednesday through 4 AM PST Friday.
The wet moisture tap from the AR will bring moderate to heavy rain
for elevations below 5,000 feet. Uplsope flow will be less of a
factor than the previos system, with rainfall amounts 1.50 to 3.00
inches in the Valley, with 3 to 7 inches in the foothills and
mountains. Rainfall will bring river rises, as well as renewed
flooding threats, mainly to small streams and creeks and to low
lying areas. This is due to streams already being elevated by the
previous storm, as well as saturated ground. A Flood Watch
continues for the Valley, Delta and foothills from Wednesday
morning through Friday morning.
The HREF and HRRR show heaviest rainfall is expected to be
Wednesday evening into early Thursday. Narrow Cold-Frontal
Rainbands have been porjected by the HRRR, which could bring
locally heavy rainfall. These could impact recently burned areas.
Confidence this far our in rain rates exceeded debris flows is
currently low, but due to the potential extreme impact a Flash
Flood Watch has been issued during the expected time period of
heaviest rainfall, from Wednesday afternoon to Thursday evening.
Lingering showers are expected on Friday, as the storm exits and
weak mesoscale ridging develops. This will be a brief lull before
the next system spreads in Friday night.
&&
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)...
Wet weather continues through the extended forecast period as
models indicate additional Pacific storms moving through but
differ with timing and QPF. CW3E AR Landfall tool points to
multiple ARs with the strongest Sunday into Monday. There is the p
otential for significant flooding issues as snow levels rise
through the extended period and run-off intensifies on already
saturated soils and elevated rivers and streams. While exact
details remain uncertain, early projected rainfall amounts are
around 2 to 4 inches in the Valley. High elevation snow totals
could be heavy and measure up to a few feet.
&&
.AVIATION...
MVFR/VFR conditions are forecast with localized IFR/LIFR ceilings
over the next 24 hours. Surface winds today generally at/below 15
kt. Southerly winds increase at the tail end of the TAF period
with possible low level wind shear in the Sacramento area
terminals and points south.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 7 AM Wednesday to 4 AM PST Friday for
Mountains Southwestern Shasta County to Western Colusa County-
Shasta Lake Area / Northern Shasta County-West Slope Northern
Sierra Nevada-Western Plumas County/Lassen Park.
Flash Flood Watch from Wednesday afternoon through Thursday
morning for Burney Basin / Eastern Shasta County-Motherlode-
Mountains Southwestern Shasta County to Western Colusa County-
West Slope Northern Sierra Nevada-Western Plumas County/Lassen
Park.
Flood Watch from late tonight through Friday morning for
Carquinez Strait and Delta-Central Sacramento Valley-Motherlode-
Mountains Southwestern Shasta County to Western Colusa County-
Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-
Northern San Joaquin Valley-Southern Sacramento Valley.
High Wind Warning from 10 AM Wednesday to 4 PM PST Thursday for
Carquinez Strait and Delta-Central Sacramento Valley-Motherlode-
Mountains Southwestern Shasta County to Western Colusa County-
Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-
Northern San Joaquin Valley-Southern Sacramento Valley.
&&
$$
Area Forecast Discussion
National Weather Service Topeka KS
425 PM CST Tue Jan 3 2023
...AVIATION UPDATE...
.DISCUSSION...
Issued at 243 PM CST Tue Jan 3 2023
Forecast Key Points:
- Near normal temperatures through Thursday, the above normal Friday
and early next week.
The mid level low was located near the Nebraska and Iowa line moving
northeast this afternoon. Areas of clouds rotating around the low
continued across much of Kansas northward into Nebraska and Iowa.
Latest surface analysis had a surface low in western Iowa with
westerly winds on the backside across northern Kansas. Temperatures
have remained nearly steady or have fallen through the day.
Expect the clouds to gradually decrease tonight from southwest to
northeast as the mid level low moves off to the northeast. Lows
tonight will drop into the low to mid 20s. Some clouds may linger or
redevelop in the northeast on Wednesday, keeping highs in the 30s
there while highs in the 40s are expected elsewhere.
A northwest flow regime will transition to weak ridging over the
central Plains on Friday as a trough moves across the west. Friday
looks to be the warmest day this week with highs in the mid 40s to
lower 50s. The western trough will moves across the Plains with a
surface low moving across Friday night and Saturday. This will bear
watching as some light precipitation will be possible with this
system. Cool advection on the backside of the departing system on
Saturday will keep highs in the 30s to lower 40s for the weekend.
Temperatures warm back up for the start of next week as heights rise
in advance of the next trough approaching the Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday)
Issued at 425 PM CST Tue Jan 3 2023
With the low pressure system still over western IA and models
showing it slow to move east, think the MVFR CIGS are going to be
hard to get rid of. The 18Z guidance is trending this way as well
keeping the CIGS until mid morning Wednesday. Bases may fluctuate
around 3 KFT but for the most part think CIGS will prevail between
2500 and 3000 feet. The RAP wants to hold onto the MVFR CIGS well
into Wednesday. But forecast soundings show the cloud layer
thinning with decent mixing. So will go with the NAM and GFS that
scatter out the low clouds by the late morning hours.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...53
AVIATION...Wolters