Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/04/20
Area Forecast Discussion
National Weather Service Caribou ME
716 PM EST Fri Jan 3 2020
.SYNOPSIS...
Weak high pressure will build across the area tonight into
Saturday. Low pressure from the Mid-Atlantic states Saturday
morning will track south of Nova Scotia by Sunday afternoon.
Weak high pressure builds Sunday night into Monday followed by
weak trough of low pressure over the area Tuesday. Stronger low
pressure from the Ohio Valley is expected to arrive Wednesday.
&&
.NEAR TERM /THROUGH SATURDAY/...
705 PM Update: Temps were adjusted to fit the latest conditions.
Clouds holding on across the CWA w/the lower clouds mainly
across the northern 1/2 of the region. Dewpoints across the
northern areas were slowly coming up. Some the higher resolution
guidance such as the NAM12 and HRRR hint at the potential for
some partial clearing later in the evening before clouds fill
back in w/the apch of the cold front. This could lead to some
fog formation. The NBM hinted at the fog potential as did the
HREF w/the highest probabilities across the Downeast. Followed
the daycrew w/the fog, but did add some patchy fog across some
northern areas given the partial clearing potential and light
winds. As far as the precip chances go, mainly slight
chance(20%) and this will be across the n and w.
Previous Discussion...
A weak cold front will cross the area this evening and
overnight. Moisture remains in place below 750mb, and if the
front has enough lift, a few isolated showers are possible
before midnight across the north. Winds will remain on the calm
side, but it may become a little breezy in the north when the
front does pass.
With dewpoints remaining elevated Downeast and cloud bases
relatively high, there is the chance for some patchy fog tonight
into Saturday morning. This is especially evident along river
valleys via the HREF vis probabilities.
Fog will linger until the front passes offshore, with weak cold
air advection. Saturday will again see above normal temperatures
for the season, but a handful of degrees cooler than Friday. 500
mb jet moves very little, but by the time the next weather
system tracks towards New England, a trough will be pushing out
of the Great Lakes. This will slow onset time of precip until
Saturday evening and overnight, although some scattered rain or
snow showers cannot be ruled out in the Bangor Region Saturday
afternoon.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Next light pcpn-maker wl be in the offing for the beginning of the
short term pd. Sfc low located ovr the Upr Midwest wl begin to drift
to the south and east tonight bfr weakening. Sfc low ovr the TN Vly
wl strengthen as it heads twd the northeast tomorrow as H5 trof
deepens back to our east.
By the start of the pd all guidance is suggesting sfc low wl be
located in vicinity of Cape Cod. Guidance has slowly come into
agreement on ultimate track of sfc low to the south of our waters.
Hv contd with mention of likely pops ovr Downeast zone for Sat
night. Question then bcms what happens further north. As mentioned
by previous shift, H8 low looks to be the catalyst for snow acrs the
north. 12z guidance rmns with this idea and hv retained chc pops
acrs the entire CWA aft 06z.
Winds look to pick up behind low pressure on Sun aftn and may result
in blowing snow acrs the north, especially over lakes and fields.
Winds look to gust to btwn 20-25kts.
Cold air streaming in on nrly flow on Sun wl drop high temps closer
to normal late in the weekend and blo normal to start off the week.
Brief ridge of high pressure wl affect the region Sun night into the
early part of Monday before next wmfnt brings overrunning pcpn to
the wrn part of the region starting late Mon aftn but weakening as
it heads east into CWA.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Vry light snow wl accompany a weak trof lifting north thru the area
Mon night. As wmfnt lifts north on Tue expected that temps wl climb
to abv normal values once again with highs in the m20s acrs the
north and abv frzg for Downeast zones.
The next in the way of significant storms appears to approach the NE
on Tue with potential Nor`easter on Wednesday. 12z GFS, EC, GEM,
UKMET and majority of GFS ensemble members showing fairly potent
storm by this time. Way too early to get specific on details this
far out but above average confidence exists for a storm. This is
still highly dependent on upr air features coming together at just
the right time thus phasing comes into question as to location of
low and ultimately ptype as a result. Either way, something to
certainly keep an eye on over the weekend. High pressure wl build
over the area as system departs on Thu with dry and cooler wx thru
the end of next week.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR ceiling conditions will persist through the
afternoon at FVE, CAR, and PQI. A period of IFR is possible for
FVE and CAR tonight as a cold front passes over. Downeast, VFR
is expected through early tonight. Patchy fog will be possible
after midnight along river valleys near BGR and the coast into
BHB through mid-morning.
SHORT TERM: Sat night...MVFR at all terminals as weak system
approaches. Downeast terminals may see IFR restrictions during
the bulk of the nighttime hours in -sn. Light N wind.
Sun...Slow improvement to VFR during the morning hours though
may see lingering MVFR stratus for northern terminals. NW wind
10-15kts gusting to 25kts.
Sun night/Mon...Mainly VFR. Light N winds Sun night becoming
light S Mon.
Mon night/Tue...MVFR in very light -sn Mon night. MVFR cigs may
linger across the north on Tue with improvement to VFR for
Downeast. Light S winds.
Wed...IFR in sn during the day. Potential for NNE winds.
&&
.MARINE...
NEAR TERM: Conditions will continue to remain below SCA criteria
with waves 2-3 feet.
SHORT TERM: SCA will likely be needed late Sat night through the
day on Sunday. Winds may come close to gales Sun aftn for the
outer waters. Winds drop blo SCA levels early Mon morning. Seas
increase abv 5 ft in srly swell Sun morning and remain above SCA
levels through midnight Sun night. Seas wl then be aob 5 feet
into the middle of the week. Winds will be under SCA levels
until early Wed morning.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...Cornwell/Hewitt
Short Term...Farrar
Long Term...Farrar
Aviation...Cornwell/Hewitt/Farrar
Marine...Cornwell/Hewitt/Farrar
Area Forecast Discussion
National Weather Service Des Moines IA
807 PM CST Fri Jan 3 2020
.UPDATE...
Issued at 753 PM CST Fri Jan 3 2020
Strong PV anomaly continues to pin wheel over central Iowa this
evening. The heaviest snowfall totals should behind us now as the
anchored band of heavy in north central Iowa has started to push
south. HRRR/RAP in solid agreement with a more westerly trend for
snowfall through the remainder of the night, likely due to drier
air that has now wrapped around the southeasterly edge of this
system. The RAP model highlights the potential for heavier
snowfall rates on the western periphery of the upper low with
appreciable lift and super saturation with respect to ice through
the dendritic growth zone. This would highlight areas generally
between Hwy 71 and I-35 over the next couple hours. The more
accelerated movement of the snowfall should limit total amounts,
but some could see a quick 1 to 2 inches, possibly up to 3 in
localized areas. Visibility may become quite low at times in areas
where heavier snowfall rates combine with gusty northwest winds.
Conditions are expected to improve overnight as the system quickly
exits the area.
&&
.DISCUSSION.../Tonight through Friday/
Issued at 318 PM CST Fri Jan 3 2020
.Overview...Quick shot of precipitation (mainly snow) this
afternoon into tonight will create tricky Friday evening travel
across parts of central Iowa. Winds will be stronger over western
Iowa where total snowfall should be less, but winds in general
with falling snow will have reduction on visibility through
snowfall end tonight. A cold front will pass through on Sunday
with gusty winds with a clipper bringing precipitation chances on
Tuesday. Temperatures will be near if not mostly above normal for
the next week.
.Details...Emphasis on this forecast cycle was on the quick shot of
snow that is already moving through this afternoon and will continue
to do so through tonight. Already have precipitation, mostly snow,
but some rain on the southern periphery, over many parts of central
Iowa mainly north of I-80. This precipitation is associated with
warm air advection ahead of the surface low that is over southwest
Minnesota early this afternoon and will be diving southeastward
tonight as the PV anomaly over central South Dakota moves in a
similar direction. Initial snow over northwest Iowa this morning did
accumulate for a bit, but at midday the roads were mainly wet as
road temperatures were near if not above freezing. However, recent
phone calls from spotters reported snow beginning to accumulate once
again over parts of north central Iowa.
Challenge today has been where the band of heavier snow may set up,
the pivot point where snow totals may be highest, and where the
highest winds will be and if they will coincide with the higher
snowfall. There has been general agreement that the band may be a
little more northwest to southeast oriented than previously
forecast. The 12z HREF and latest WPC and NBM are highlighting a
corridor from our northwest forecast area through our east central
(roughly Estherville to Marshalltown line) as the axis of highest
snowfall. Snowfall rates may exceed 1"/hr at times in this corridor
as shown by the 12z HREF and recent HRRR and cause significant
reduced visibility. As for the pivot point, the 12z HREF 4"
probability has relatively higher probabilities over Tama and
Marshall counties and latest NBM and some other CAMs also indicate
a longer duration of snow as the system pivots through this
evening over this area. While current forecast is around 2.5 to 3
inches in this area, it may need further refinements going forward
this evening. Overall, the snowfall forecast has narrowed the
swath of highest snowfall.
As for winds, the core of the strongest winds should remain west the
surface low over western Iowa as the low moves southeastward over
central Iowa. This will create visibility reduction to a degree, but
it is not clear if it will be to the same reduction where snow rates
may be higher. Further, it is also expected near and west of the low
track that snow duration will be shorter than in the pivot
point/east of the low track. So, for now, have continued to focus
Winter Weather Advisory along the low track and through the pivot
location where snow totals and impacts may be greatest. Trends
upstream will need to be watched this evening for any possible
expansion.
This quick system will exit the area overnight with snow ending from
northwest before midnight to southeast before daybreak Saturday. A
transient mid-level ridge will pass over the state on Saturday with
increasing amounts of sunshine and dry conditions. Another cold
front trailing from a surface low pressure moving over southern
Canada will cross the state Saturday night into Sunday morning.
Soundings show an increase in moisture in the mid-levels, but not
enough for precipitation. However, in the cold air advection
regime expect gusty winds to develop behind the front early Sunday
morning through midday Sunday before decreasing later in the
afternoon. Winds at this point remain on the cusp of a wind
advisory so will need to keep a watch on this time period.
Into next week, there are two possible systems with mid-level
ridging fostering dry conditions between them. The first will be
later Monday into Tuesday and will bring light snow (perhaps
initially rain) as a clipper passes quickly through the region.
The latter system later Thursday into Friday may bring a shot of
precipitation with the highest chances over the southeast part of
the state. However, like today`s system a week ago, it will
depend on phasing of a northern and southern stream wave, which
remains uncertain at this time.
&&
.AVIATION.../For the 00Z TAFS through 00Z Saturday evening/
Issued at 535 PM CST Fri Jan 3 2020
Snow and low stratus will be the main forecast concerns for the
current TAF period. Cigs have been up and down over central Iowa
for the last few hours, ranging anywhere from MVFR to LIFR at
times. Expecting IFR to prevail at most TAF sites into the
overnight hours along with visby restrictions from passing -SN/SN.
Expect gradual improvement from west to east across the area
Saturday morning and afternoon as cigs rise and cloud cover
diminishes.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 1 AM CST Saturday for IAZ039-
047>050-061-062.
Winter Weather Advisory until 9 PM CST this evening for IAZ004-
005-015>017-023>028-035>038.
&&
$$
UPDATE...Martin
DISCUSSION...Ansorge
AVIATION...Martin
Area Forecast Discussion
National Weather Service Goodland KS
414 PM MST Fri Jan 3 2020
.SHORT TERM...(This evening through Saturday night)
Issued at 119 PM MST Fri Jan 3 2020
Water vapor imagery and 500 mb RAP analysis showed northwest flow
over the region today as a trough pushed east across the Plains. To
the west, upper ridging built along the west coast. Some mid level
clouds traveled over the area, with northwest winds observed at
generally 10 to 20 mph. At 1 PM MST, temperatures were mainly in
the low 40s.
Dry weather is expected to continue tonight as high pressure moves
into the region ahead of the upper ridge. Mid level clouds could
increase in the evening, particularly east of the Colorado border,
before clearing after midnight. Temperatures fall into the low 20s,
with light winds shifting from northwest to west.
Mostly sunny skies are forecast on Saturday as high pressure moves
southeast and a weakening ridge progresses to the Plains. Warmer air
filters into the region and temperatures climb into the mid 50s to
low 60s, with southwest winds at 15 to 20 mph.
A shortwave traverses the northern Plains Saturday night, sending a
cold front through the area. No precipitation is currently
anticipated, but breezy northwest winds appear likely behind the
front. Due to mixing, temperatures stay a little warmer in some
places, ranging from the low to upper 20s.
.LONG TERM...(Sunday through Friday)
Issued at 149 PM MST Fri Jan 3 2020
The forecast will remain dry with near normal temperatures through the
extended forecast. Normal temperatures for this time of the year
are in the low 40s for highs and the mid-teens for lows.
A deamplifying ridge will move over the Tri-state region through the day
Sunday. A deepening upper trough coming ashore over the West
Coast will progress eastward over the Rockies. High temperatures
will be right around normal, ranging from the low to mid-40s. Lows
will be in the low to mid-20s.
Monday will be breezy as the trough advances into the Central High Plains
and a surface lee cyclone develops. Though mid-levels do try and
moisten up through the afternoon as the low moves through, am
currently looking at dry conditions remaining prevalent through
the day. Highs will top out in the 40 with lows ranging from the
mid-teens to mid-20s. Northwest flow aloft will set up over the
Central High Plains on Tuesday with a ridge over the West Coast.
The ridge will move eastward, over the Tri-State area by
Wednesday. Wednesday is expected to be the warmest day of the
extended forecast with highs ranging from the mid-40s to mid-50s.
A broad, upper level trough will move into the region on Thursday
with a low moving through the Dakotas and a cold front pushing
into the Tri-State region from the northwest. Precipitation is not
expected, however, temperatures will be impacted, returning to
near normal with highs in the low to mid-40s and lows in the mid-
teens to low 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 412 PM MST Fri Jan 3 2020
VFR expected at both KGLD and KMCK through the TAF period.
Occasional high clouds will spill across the Rockies with a ridge
located over the western CONUS. At the surface, winds will be
light and variable tonight, but some increase from the southwest
by Saturday afternoon as a trough of low pressure develops across
eastern Colorado.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JBH
LONG TERM...AW
AVIATION...024
Area Forecast Discussion
National Weather Service Wilmington NC
929 PM EST Fri Jan 3 2020
.SYNOPSIS...
A pair of cold fronts will bring showers to the area through
early Saturday. High pressure will rebuild from the Gulf Coast
states Saturday night through Monday. This will allow cooler and
drier area to impact the region. The next cold front approaches
Tuesday before pushing offshore into Wednesday.
&&
.UPDATE...
Tweaks to temperatures and timing of showers was the main focus
of this late evening update. 01z HRRR run looks very reasonable
with its eastward movement of precip overnight into Saturday
morning. Elevated instability is diminishing across the Pee Dee
region into Lumberton and I have removed thunder from the
forecast there. Dense sea fog continues offshore, and south-
southwest wind is keeping visibility very low in Southport and
Oak Island according to webcams.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
Main concern over the next 36 hours includes chances for moderate to
heavy rainfall at times during heavier showers and isolated
thunderstorms.
Surface low pressure system developing out of the Gulf of Mexico
will bring developing fronts passing through the Carolinas. A warm
front pushes through the region today with high temperatures in the
mid to upper 70s, which is on average about 20 degrees above normal
for early January. A cold front approaches from the west and will
bring chances for rain showers and isolated chances for thunder
mainly to locations along and west of I-95 this evening. Latest
model guidance indicates the line will become more disorganized and
scattered as it approaches the coast late this evening into the
overnight hours. Chances for rain will continue Saturday with
scattered precipitation until a second cold frontal passage occurs
late Saturday into early Sunday morning with rain moving off the
coast.
Temperatures Saturday will drop into the mid to upper 60s, which is
still on the order of about 10 degrees above normal, but the second
frontal passage will bring low temperatures Saturday night into the
upper 30s to lower 40s, which is closer to normal for early
January.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A different air mass will be over the area on Sunday as deep layered
NW flow ushers in dry conditions (pwat around 50% of normal), cooler
high temps in the low to mid 50s, and abundant sunshine. Subsidence
inversion above ~2500ft will limit mixing but with center of
~1030mb surface high still well to our SW near central Gulf
Coast, expect NW winds 8-13 with gusts to 15-20mph to persist,
making temps feel a little cooler than they really are. The
surface high will gradually settle over the SE US as it weakens
through Monday allowing winds to gradually diminish. Meanwhile,
mid and upper flow will become more zonal. This leads to a
chilly start on Monday morning (mid to upper 30s), with another
dry and sunny day warming to slightly above normal values into
the upper 50s to near 60 most zones.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The next deep layered trough and associated sfc cold front
approach on Tuesday. Expect prefrontal airmass to lead to warmer
temps (low-mid 60s) and an increase in clouds. Most of the
daylight hours currently look dry although have maintained low
chance pops far western counties which is in line with latest
guidance trends. Better precip chances exist Tue night as
forcing improves aloft with PVA ahead of H5 trough and sfc
boundary swings through. Moisture overall is lacking though so
have kept PoPs in the low chance variety for now. Wednesday and
Thursday look dry and cooler as airmass changes again with deep
layered ridging taking over. Wednesday/Wednesday night has the
potential to be the coolest period of the forecast although am
only advertising slightly below normal at this time. Showing a
slow, modest increase in PoPs at the end of next week as next
frontal system begins to impact the area, but low confidence in
related specifics at this time.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
IFR sea stratus affecting coastal terminals attm due to warm, moist
southerly flow over cool water. Area webcams showing scattered IFR
fog too but that isn`t affecting the terminals attm. It could
impact approaches, especially in SC. Expect this fog and stratus to
persist for several hours, perhaps until winds become more westerly
later tonight.
Bands of showers moving in from the west should begin to affect
inland terminals in the 01Z to 03Z time frame and reach coastal
terminals in the 06Z to 09Z window. Generally expect MVFR cigs with
the bands of showers though tempo IFR is not out of the question. It
should take until about 18-20Z for cigs to improve to VFR and for
shra to end.
Expect S to SW winds of 10 to 15 KT with higher gusts to become SW
late tonight and W to SW after sunrise. LLWS potential exists at
times all terminals tonight, mainly in the 02Z to 08Z time frame.
Extended Outlook...VFR conditions return for Saturday night through
Monday. Cold frontal passage expected late Tuesday could produce
MVFR conditions showers.
&&
.MARINE...
Small craft advisory (SCA) begins this afternoon and evening as
cold front approaches from the west. As warm air moves over the
waters for the next ~12 hours, dense marine fog is a possibility
especially near shore. Another cold front will push through the
offshore waters late Saturday and could bring even worse
conditions as gales are possible. Waves 4 to 7 feet this
afternoon through Saturday with winds shifting from the south to
the southwest at 15 to 20 kts and gusts in excess of 25 kts
into Saturday afternoon. Conditions worsen Saturday evening with
waves between 6 and 10 feet and a hard wind shift from the
southwest to the northwest at between 25 and 35 kts with gusts
up to 45 kts at times.
Expect the potential NW gales from Saturday night to ease to
SCA levels through Sunday morning, and then come down below SCA
threshold through Sunday afternoon as the recent cold front
pushes further offshore and high pressure slides east along the
Gulf Coast. Much tamer marine conditions develop during Monday
as high pressure settles over the area allowing winds/seas to
fall to at or below 10kt/3ft. Return flow develops Tuesday ahead
of next front, with potential for low end SCA conditions later
Tuesday and Tuesday night. Gusty W/NW winds and associated short
period seas may keep marine conditions hazardous into Wednesday
behind the front.
&&
.CLIMATE...
As recently highlighted on our social media outlets
(@NWSWilmingtonNC), Florence, SC and Lumberton, NC have broken
high temperature records, both hitting 79 degrees. Meanwhile,
Wilmington has tied its record high of 77 degrees. Expect more
info in our RERFLO, RERLBT, and RERILM text products around 5pm.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...Dense Fog Advisory until 7 AM EST Saturday for NCZ110.
MARINE...Dense Fog Advisory until 7 AM EST Saturday for AMZ250-252-254-
256.
Gale Watch from Saturday evening through Sunday morning for
AMZ250-252-254-256.
Small Craft Advisory until 9 PM EST Saturday for AMZ250-252-
254-256.
&&
$$
SYNOPSIS...MCW
UPDATE...TRA
NEAR TERM...MCK
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...RAN
CLIMATE...MCW
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
540 PM CST Fri Jan 3 2020
.SYNOPSIS...
Issued at 311 PM CST Fri Jan 3 2020
H5 analysis from earlier this morning had a large ridge
of high pressure extending from southern California north into
British Columbia and Alberta. East of this feature, a strong
shortwave and trough of low pressure extended from the western
Dakotas into northeastern Nebraska. Another shortwave trough of low
pressure was located from central into southern Texas. East of these
two features, broad southwesterly flow extended from the Gulf of
Mexico into the Mid Atlantic. Across the central CONUS this morning,
the Dakota shortwave had led to snow showers across eastern South
Dakota, and forced a cold front through the forecast area earlier
this morning. Winds were gusty behind the exiting cold front,
particularly over northern and northeastern portions of the forecast
area. As of 2 PM CST, winds were gusting as high as 31 MPH at
O`Neill and temperatures were in the 30s to around 40.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 311 PM CST Fri Jan 3 2020
The main forecast challenges in the
near term are temperatures and wind potential. For tonight: Surface
high pressure, will build south from north central Nebraska into
central Kansas tonight. On the western periphery of the high,
abundant mid level cloudiness will persist into the evening hours
across western portions of the forecast area. Clouds will then begin
to dissipate overnight as the high builds south into Kansas. As for
the threat for light precipitation tonight on the western periphery
of the high, the latest NAM12 soln does generate some very light
precipitation from the Pine Ridge into the western Sandhills early
this evening. With each run of the HRRR this morning, dry conditions
continue to be advertised. With no model support for pcpn other than
the NAM12, will hold onto a dry fcst for tonight. A warm front will
push east of the area Saturday morning with a pre frontal trough
extending across the forecast area Saturday afternoon. Winds will be
relatively light during the afternoon along the trough. The latest
MAV guidance has mid to upper 50s for highs Saturday for Valentine
and North Platte. With limited mixing along the surface trough
Saturday afternoon and snow cover, will opt for the cooler MET
guidance which favors highs from the mid 40s to around 50 over snow
covered areas. Across far southwestern portions of the forecast
area, highs will top out in the middle 50s. A clipper system will
track along the ND/Canadian border Saturday night, forcing a cold
front through the forecast area. Gusty winds will develop behind the
front Saturday night with the strongest winds expected over north
central into northeastern areas. The models do drop an area of
strong H85 winds from South Dakota into Nebraska Saturday night. The
degree as to how much of this wind can mix to the surface is still
uncertain. The latest Bufkit sounding data, including the GFS and
NAM12 solns, do not mix winds much off of the surface Saturday
night. Even mixing up to H900 Saturday night only yields gust
potential to 40 to 45 MPH. With the FROPA being at night, mixing
potential will be limited somewhat. That being said, do not see any
issues with headline type winds Saturday night. The blowing snow
threat should be very limited as well as recent warm days have
crusted over the existing snow cover across the forecast area.
.LONG TERM...(Sunday through Friday)
Issued at 311 PM CST Fri Jan 3 2020
Surface high pressure will build into the area Sunday with mainly
clear skies and light winds. Highs Sunday will be in the lower
40s. A weak clipper system will track across North Dakota Sunday
night into Monday. There will be an increased threat for rain or
snow showers Monday. Given the fast movement of the system and a
lack of moisture, any precipitation will be very light. After
Monday, a dry pattern will continue as ridging builds into the
central CONUS Tuesday into Wednesday. A southern stream trough
will bring precipitation to the southern plains and Mississippi
valley late Thursday into Friday. This will be followed by another
ridge building into the central Conus Friday night into Saturday.
Highs next week will generally be in the upper 30s to 40s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 539 PM CST Fri Jan 3 2020
Scattered flurries underway across wrn Nebraska are expected to
move south and out of the area this evening. VFR is expected
thereafter throughout wrn and ncntl Nebraska.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...CDC
Area Forecast Discussion
National Weather Service Marquette MI
628 PM EST Fri Jan 3 2020
.SHORT TERM...(This evening through Saturday)
Issued at 324 PM EST FRI JAN 3 2020
GOES visible shows mostly overcast skies across much of the Upper
Great Lakes region as RAP analysis shows a passing wave across the
Dakota/MN border. This wave is bringing -SN across MN/IA this
afternoon, but the UP remains dry. Temperatures remain a touch above
normal this afternoon and should remain at or slightly above normal
through the short-term period.
Heading into tonight, GFS and WRFs 850mb temps remain warmer than
NAM/EC/GEM, -7C to-8C vs -10C to -12C, but have chosen to continue
the light -SHSN/-FZDZ chances tonight. Model soundings show limited
DGZ saturation with inversions at or below 3000 feet depending on
model/location. A shortwave trough will also be passing across Upper
Michigan tonight, which may give a little extra push for some
flurry/fzdz development. There are a few model soundings that dry
out further tonight cutting off these chances. Overall have
generally capped chances at 20% or less as any precipitation will
likely create minimal accumulations and impacts, similar to this
morning`s light fzdz/flurries. By Saturday morning, the shortwave
from overnight will be east of the UP as rising heights and slight
ridging builds in from the west. Winds are expected to slowly back
from the SW by the afternoon, but lingering nuisance precip chances
will remain until these winds change over.
.LONG TERM...(Saturday night through Friday)
Issued at 414 PM EST FRI JAN 3 2020
Models suggest that a progressive pattern will prevail into next
week with shortwave troughs bringing periods of light snow followed
by batches of colder air with LES. Temps are expected to drop below
average from Tue into Wed with recovery later in the week as WAA
strengthens ahead of a developing mid level trough in the wrn CONUS
and sfc troughing moving toward the Upper Mississippi Valley.
Saturday night, lingering anticyclonic w to wnw flow along with 850
mb temps to around -10C may support some light lake effect pcpn into
the Keweenaw and northeast portion of Upper Michigan. With
relatively shallow moisture, inversion heights from 3k to 4k ft,
some fzdz may mix in with any light snow or flurries.
Sunday, a shortwave trough moving in from the Northern Plains with
moderate 700-300 qvector conv will support widespread light snow
across Upper Michigan. However, with limited moisture inflow,
accumulations are expected to remain in the 1 to 2 inch range. Some
additional lake enhancement may be possibly with southerly flow off
of Lake Michigan, but with marginal instability, 850 mb temps to -7C,
and a veering vertical wind profile any amounts should remain light.
Gusty west winds will develop, especially over the Keweenaw, behind
the surface trough with strong CAA and isallobaric gradient.
Sunday night into Monday, w-wnw flow LES will increase as 850 mb
temps drop to around -15C. Although amounts may be limited as the
deeper (850-700 moisture) lifts off to the northeast, advisory level
accumulations are still possible if any persistent areas and
stronger bands develop especially to the east of Munising.
Tue-Wed, another shrtwv trough with a batch of light snow is
expected Tue with even colder air (850 mb temps to near -20C) in its
wake that will bring nw flow LES.
Thu-Fri, conditions will moderate with the potential for some light
WAA snow. A cold front with somewhat colder air will then move
through toward the end of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 626 PM EST FRI JAN 3 2020
Expecting MVFR cigs to prevail at the terminals through the
forecast period with a chance of temporary higher-end IFR cigs at
IWD. There is a chance for some -SHSN or -FZDZ tonight downwind
of Lake Superior but will likely remain sporadic so have left it
at VCSH for now.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 324 PM EST FRI JAN 3 2020
NW winds will back to the SW on Saturday night as a developing low
pressure system approaches Lake Superior from the NW in Canada.
Pressure falls ahead of this low pressure will help increase the
winds in addition to the increased pressure gradient. Winds veer to
the NW by Sunday afternoon increasing to gale force by Sunday
evening through Sunday night, a gale watch has been issued. Expect
these NW winds to slowly diminish through the day Monday into
Tuesday and will remain below 25 knots through Thursday. Some models
suggest a low pressure system to develop across the Northern Plains
which may increase winds from the south up to 30 knots.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Watch from Sunday evening through Monday morning for
LSZ249>251-265>267.
Gale Watch from Sunday afternoon through Monday morning for
LSZ162-240>245-263-264.
Lake Michigan...
None.
&&
$$
SHORT TERM...JAW
LONG TERM...JLB
AVIATION...Voss
MARINE...JAW
AREA FORECAST DISCUSSION
National Weather Service Charleston WV
1009 PM EST Fri Jan 3 2020
.SYNOPSIS...
Low pressure brings rain into Saturday. Cold front passes early
Saturday. Colder air arrives with snow showers Saturday night.
Another cold front crosses early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1000 PM Friday...
The forecast holds strong and no changes were needed at this
time. Rainfall amounts will continue to slowly taper off
through the period.
As of 620 PM Friday...
The forecast remains on track and no changes were needed at
this time.
As of 1250 PM Friday...
This is one of those periods where confidence is high that
there will be light to moderate rain around for most of us, but
a few hours of dry are possible here and there. Have generally
low confidence on timing those out individually, so a more broad
brushed approach was used for POPs, utilizing a blend biased
towards the NAM and HRRR to try to capture some of these times
of lower precip chances. So do have a period of chance POPs
across the eastern forecast area this afternoon, gradually
filling back in as the next slug of rain arrives from the
southwest.
A couple waves of low pressure at the surface followed by an
upper trough/low will drive the overall pattern tonight and
Saturday. The first will ride up through the middle Ohio River
Valley overnight, gradually pushing a cold front through from
west to east. Another wave develops along the front Saturday,
slowing is progression down a bit as it tries to cross the
Appalachian spine. Have the area of highest POPs transitioning
across the forecast area overnight into Saturday with these
waves and cold front. By Saturday afternoon, the upper level
trough axis moves into the middle Ohio River Valley, turning the
precipitation to more showery in nature by late afternoon.
Colder air also arrives with this feature, and rain should begin
transitioning to snow late Saturday. At the surface, expect
nearly steady to slowly falling temperatures through the day as
cold air begins filtering in.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 110 PM Friday...
Colder air moving into the region behind departing cold front
will result in a change over to light snow area wide Saturday
night. Still looking at less than half an inch across the
lowlands, with a general 1 to 4 inches across the higher
terrain. In addition, gusty winds are expected Saturday night
into early Sunday across the area, particularly the higher
terrain. A few spots 3500-4000 feet elevation could hit
advisory criteria gusts of 40 kts, but coverage not expected to
be enough to warrant an advisory.
Light snow showers are possible across the north late Sunday
night into Monday from a passing disturbance to the north, but
any impacts should be limited.
Another disturbance will affect the region mid week with rain
and snow showers once again with light accumulations possible.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 150 PM Friday...
A trough moves across the area Wednesday bringing a precipitation
chance. Snow may fall early in the day and then change to rain as
the day progresses; however, in the mountains, snow will likely
linger throughout the day and taper off overnight. High pressure is
expected for Thursday and part of the day Friday. This is followed
by another trough that may yield precipitation over the weekend.
Temperatures are expected to remain cool on Wednesday and then warm
up above normal again through the end of the work week as warm air
is pulled into the area ahead of the next system.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 640 PM Friday...
Unsettled weather persists through this period along with low
MVFR to around IFR CIGs and variable VIS as low as IFR. A
southwest flow changing over to a more westerly flow by sunrise
will advect cooler air in as a cold front sweeps through the
area. This will cause post frontal stratus to occur at all sites
bringing down CIGs to essentially widespread IFR. Visibility
will improve early Saturday morning as the front kicks out and
winds pick up out of the northwest pulling in drier, cooler air.
This will help much of the area to eventually improve to VFR
VIS by sunrise although CIGs will get little improvement until
late afternoon. The eastern mountains will not gain much
improvement to either categories and eventually worsen as an
upper level trough brings in more precipitation late Saturday
afternoon maintaining around low MVFR conditions into Sunday
morning.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Timing of category changes may vary into
Saturday afternoon.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 01/04/20
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY M H H H H H H H M M H H
HTS CONSISTENCY L M M H H M M L H H H M
BKW CONSISTENCY H H M H H L H H M M H M
EKN CONSISTENCY H M H M M M M H H L M L
PKB CONSISTENCY H H H M H M M M M H H M
CKB CONSISTENCY M M M L L M M M M M M M
AFTER 00Z SUNDAY...
IFR conditions possible in rain and low clouds for the higher
elevations trough Saturday night and also in snow showers
from Saturday night through Sunday morning.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...MZ/JP
NEAR TERM...MZ/JZ
SHORT TERM...SL
LONG TERM...JLB
AVIATION...JZ
Area Forecast Discussion
National Weather Service Blacksburg VA
651 PM EST Fri Jan 3 2020
.SYNOPSIS...
Passing waves of low pressure will bring spotty rain to the
mid- Atlantic region this evening and tonight. A cold front will
pass east across the central Appalachians on Saturday,
resulting in gusty northwest winds and mountain snow showers for
Saturday night. High pressure will return for Sunday, resulting
in clearing skies and near-seasonable temperatures.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 651 PM EST Friday...
High wind watch for Saturday evening into Sunday morning is in
effect for along the southern Blue Ridge mountains.
Modified the temperatures with the latest surface obs, and
their trends for this evening into tonight. Periods of
rain,drizzle and fog are expected to continue tonight into
Saturday morning. Still looks like the heaviest rain will occur
across the southeastern portions of the forecast area. The HRRR
and HiRes Arw-East keep the stronger convection to our south
with the better instability and some outflow boundaries to work
with. More changes later tonight.
As of 330 PM EST Friday...
Doppler radar indicates widespread light to moderate passing
across the central Appalachians through the mid-Atlantic this
afternoon as waves of low pressure pass across the region in
this unseasonably- moist southwesterly windflow. Synoptic
analysis indicates a deep upper level trough situated across the
Plains states, with a surface cold front stretching from the
central Great Lakes through the western Gulf coast.
This evening and overnight, expect rounds of rain to pass
across the area. Heaviest/most widespread rainfall will occur
across the Virginia Southside into north-central North Carolina,
where deepest moisture is located - precipitable water values
here edging around or above 1.5 inches. That stated, do not
anticipate rainfall rates or amounts that will amount to any
flooding, with totals by Sunday morning in the 1.00 to 1.25 inch
range. Amounts further north and east will be significantly
lower. The deep moisture and widespread cloudcover will also
maintain patchy, locally dense fog, especially where the low
clouds intersect the higher terrain. Expect little change from
evening temperatures, with lows tonight ranging from the
mid/upper 40s across the mountains to the low 50s for the
Piedmont.
The cold front will pass east across the central Appalachians
on Saturday morning, causing winds to shift westerly with its
passage. Wind speeds will gradually increase through the
afternoon as high pressure builds in, though strongest winds
will not arrive until the base of the upper level trough moves
through Saturday night. Downsloping will make for clearing
conditions in the east and a wider range of afternoon
temperatures, with afternoon highs ranging from the upper 40s
west to the low 60s east. The approaching upper trough will
also bring colder air during the afternoon/evening which will
cause rain to change over to snow showers by sunset across
western Greenbrier County.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 200 PM EST Friday...
The biggest concern post-cold front will be an increasing
northwest wind. The latest guidance offers a solution of 6mb
pressure rises maximized Saturday night with 850mb winds around
40 to 50 kts right at or slightly below the inversion height.
The area along the crest of the Blue Ridge between roughly
Boone, NC and Roanoke, VA looks to have the greatest impact with
the winds. There is a concern for wind gusts approaching the
60mph threshold Saturday night with a gradual tapering Sunday
morning. Will be issuing a High Wind Watch for this area. Much
of the rest of the region west of the crest of the Blue Ridge,
and perhaps even a couple tiers of counties east of the crest of
the Blue Ridge could be strong candidates for Wind Advisories.
However, we are still going to allow for one more look of the
newest guidance tonight to see how well/poor this potential is
trending. However, the current forecast time is appropriate for
heightened awareness for the potential for the high winds, hence
our High Wind Watch.
These strong northwest winds ushering in colder temperatures
will have the impact also of lifting residual low level moisture
not only into clouds, but first rain showers, and then
transition into snow showers as the night progresses. Our
current forecast has most locations between roughly western
Greenbrier County, WV south into the Northern Mountains of North
Carolina with less than one inch of snow during the Saturday
night/early Sunday time frame. However, higher elevations could
see snowfall in the one to three inch range, with an even
smaller subset of peaks in the four to six inch range. No
advisories for snowfall are planned at this time given the
timing of the event still more than 24 hours away, and the less
than desired amounts and areal coverage to justify an advisory
at this time. Blowing snow could become a winter headline factor
across the Northern Mountains of North Carolina as this would
be an area that can expect the very strong/damaging winds plus
at least a small covering of snowfall.
By Sunday afternoon, low level winds are forecast to have
backed to the west-southwest. While still maintaining healthy
speeds, their orientation will not be as conducive for mixing
to the surface or helping to generate snow showers. While
eastern parts of the region will have clear skies by daybreak
Sunday, the remainder of the region should see skies clear by
early Sunday afternoon.
Sunday night, the low level flow veers northwest again, but the
amount of drier air that will have arrived across the region
will limit any upslope cloud/snow shower development. Perhaps
western Greenbrier County, WV will see some isolated snow
showers Sunday night. We will have to continue to monitor these
trends, but indications are looking promising again for
additional wind headlines Sunday night into early Monday, with
the best probability this time across northern sections of the
forecast area.
Surface high pressure will be across the region by Monday
afternoon, and start to transition to the coast by Monday night.
This will be in response to an approaching upper level trough
that will be heading toward the mid-Mississippi River Valley.
Low level winds across the region will trend southwest. This
will mean a trend towards warm air advection, and moisture
levels will start to increase. Clouds will be on the increase
across the area by midnight, some patchy light precipitation
will be inching its way northward across the far western parts
of the forecast area. There is some question to just what the
low level thermal profile will be in regards to the p-type. At
this time, will keep the forecast a simple rain versus snow
forecast based solely upon the surface temperatures.
Temperatures during this portion of the forecast will about
five to ten degrees above normal.
Forecast confidence during this segment of the forecast is
moderate.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 1230 PM EST Friday...
Tuesday into Wednesday, we are expecting precipitation across
the area thanks to two systems. The first system will have its
origins as a developing shortwave trough in the Central Plains
states Monday night. By Tuesday, this feature will head across
the mid-Mississippi River Valley. In advance of this feature,
southwest flow will develop, and help advect Gulf of Mexico
moisture into the region. However, this advection is not
expected to be as robust as compared to similar systems so far
this winter. An associated cold front will cross the area
Tuesday evening, but this is also about the same time the
second system make its contribution. The next system will be a
northern stream shortwave trough that will head across the Great
Lakes region Tuesday night and bring its own reinforcing cold
front through the region.
Precipitation on Tuesday is expected to be primarily rainfall,
with a few pockets of wintry weather possible at the highest
elevations immediately at the onset Tuesday morning, and then
again towards the late afternoon as temperatures start to cool.
Tuesday night, we expect a switch to rain showers. As
temperatures continue to fall through the night, coverage of
snow showers is expected to increase from west to east across
the region. Gusty winds are expected behind the system on
Wednesday, along with some lingering isolated to scattered snow
showers across the mountains.
Wednesday night into Thursday, high pressure will first be
centered over the region, and then shift east to the coast. This
will allow for dry conditions, and the start of temperatures
beginning to moderate a little.
A trend toward milder and wetter conditions will take place
Thursday night into Friday. Another trough is expected to be
making headway east towards and then east of the Mississippi
River valley. A generous fetch of Atlantic and Gulf of Mexico
moisture is expected to stream into the area in advance of this
system. This will result in increasing chances of precipitation
across the region, and rising temperatures. Near the beginning
of the precipitation, there may be a few pockets where the low
level thermal profile may support some wintry precipitation.
Temperatures during this portion of the forecast will start
around five to ten degrees above normal on Tuesday, five degrees
above normal for on Wednesday, near normal Thursday, and five
to ten degrees above normal for Friday.
Confidence in the above weather scenario is moderate.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 640 PM EST Friday...
Generally poor flying conditions are expected tonight into
Sunday morning, with gradually improving conditions expected
thereafter. Low pressure moving across the region this evening
into tonight will result in widespread IFR/LIFR ceilings as
well as pockets of IFR visibility. Rain will diminish this
evening into tonight. This will allow the low clouds to break up
from time to time, only to fill in again after a short while.
Areas of IFR fog and drizzle will form tonight into Saturday
morning, especially across the mountains where the ceilings
intersect with local terrain.
On Saturday, winds will shift westerly and increase in speed
during the late morning as a cold front passes from west to east
across the area. Gusts across higher terrain may reach 25 knots
Saturday afternoon and continue to increase into the evening.
Expect gradual improvement in ceilings and visibility along/east
of the Blue Ridge during late morning into the afternoon in the
downslope flow. IFR ceilings will remain in place at BLF as
winds shift increasingly northwesterly. Once enough cold air
arrives in the west, snow showers will develop in the western
upslope areas.
Confidence is low to moderate for ceilings and visibilities.
Extended Aviation Discussion...
Saturday evening into Sunday, the low pressure system will
depart offshore, which will result in a continuation of flight
restrictions in mountain clouds and snow showers, along with
gusty northwest winds - with a return to VFR weather as skies
clear in downsloping areas east of the Blue Ridge. Flying
conditions should improve back to VFR in the mountains later
Sunday night into Monday, and persist into Tuesday, as high
pressure arrives from the west. A few MVFR snow showers may be
possible Wednesday morning into the western mountains.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...High Wind Watch from Saturday evening through Sunday morning
for VAZ015>017-022-032-033.
NC...High Wind Watch from Saturday evening through Sunday morning
for NCZ001-002-018.
WV...None.
&&
$$
SYNOPSIS...NF
NEAR TERM...KK/NF
SHORT TERM...DS
LONG TERM...DS/WERT
AVIATION...KK/NF
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php