Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/03/17
Area Forecast Discussion
National Weather Service Wakefield VA
940 PM EST Mon Jan 2 2017
.SYNOPSIS...
A stationary front will remain over the Carolina coastal plain
overnight, before slowly tracking back north as a warm front
Tuesday as low pressure passes through the region. A cold front
crosses the region later Wednesday, with weak high pressure
building into the area Wednesday night into early Thursday.
&&
.NEAR TERM /THROUGH TUESDAY/...
Evening update...Convective complex continues to rumble across the
deep south this evening. Next batch of rainfall extends from the
mid-south (S KY/Central TN back toward South Central GA, just
ahead of SFC warm front. Coastal trough remains aligned sw-ne
along the Carolina coast, with 1020mb low pressure associated
with the RRQ of a 110kt jet aloft has now pushed off the Delmarva
coast.
Most of the area remains within the CAD wedge airmass this
evening, with the exception of ne NC adjacent to the Albemarle
Sound and Atlantic Coast. Accordingly, expect little change (light
rain/drizzle) into the early overnight hours. By late tonight, the
time-lagged HRRR and RAP are in good agreement in bringing next
slug of moisture up the I-85 corridor into the Piedmont after
07-09z/2-4am EST. Pops increase to high end likely then back into
categorical range (AOA 80%) during and after this time late
tonight into Tuesday morning. Will also include areas of fog all
zones overnight with increasing Dewpoints/lowering Cond. Pressure
Deficits overnight. Some locally dense fog is possible along the
eastern half of the area, but will hold off on any statements or
headlines for now.
Temperatures will fall little overnight with lows ranging from
the low/mid 40s over the Piedmont to the upper 40s/low 50s se.
Next slug of moisture, associated with next trough pushes from
the Tennessee Valley tonight to the Mid-Atlantic Tuesday morning.
Categorical PoPs continue across the entire area Tuesday morning
through midday. At this time, additional QPF is expected to
average 0.5-0.75" for most of the area. A slight chc/chc of
thunder has been maintained for far se VA/ne NC where some
instability is present for late Tuesday morning into the aftn. A
dry slot pushes into the region during the aftn, so PoPs taper to
chc from sw-ne. The latest data continues to show that it will be
difficult for the wedge airmass to fully erode, so highs should
only be around 50 far nw, to the low/mid 50s for central portions,
and low/mid 60s far se.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A drier airmass pushes into the area Tuesday night,
with a cold front approaching from the nw later Wednesday aftn. Lows
Tuesday night range from the low 40s nw, to low 50s se. There will
be a lack of CAA, so some low-level moisture may linger, which could
result in patchy stratus or fog. The airmass Wednesday will be mild
and somewhat more mixed with the approach of a cold front.
Therefore, forecast highs range from the mid/upper 50s nw to the low
60s se.
The cold front will cross the region late Wednesday aftn into the
evening. Colder and drier air will gradually filter in from the nw,
with lows dropping into the upper 20s nw to mid 30s se. Weak high
pressure is progged to be over the area early Thursday, with weak
low pressure approaching from the west by aftn. Variably cloudy to
eventually mostly cloudy conditions are expected, with a slight chc
of light rain or light snow across nw portions by aftn. Forecast
highs range from the upper 30s nw to the mid 40s se.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Confidence is still not high regarding the extended period forecast,
but there have been incremental steps toward a workable forecast.
The issues now reside in developing a southern system low over the
Southern Plains or along the Southeast coast Friday night. The
ECMWF/CMC remain in good agreement (with good run to run continuity)
with developing the low along the Southeast coast, while the UKMET
and several members of the GEFS begin to trend toward the ECMWF/CMC.
However, the deterministic GFS continues to be a troubling outlier,
lifting the Southern Plains low into the region Saturday night
resulting in a major winter storm over the region. Based on it being
a significant outlier and the inconsistent run to run continuity,
have opted to trend the extended period forecast significantly
toward the ECMWF/CMC. With that said, there is increasing confidence
of some light wintry precipitable Thursday night as height falls
arrive along a weak boundary and developing low pressure along the
coast. Moisture will be limited, so any precipitation that does fall
will be light with little QPF expected. Expect a lull in POP`s
Friday as the front remains along the coast and another area of low
pressure develops along the Southeast coast ahead of more
substantial height falls from the approaching upper level trough.
Highs Friday in the upper 30`s to mid 40`s. Precipitation chances
ramp back up Friday night as the low lifts along the coast. Have
increased POPs to 30-40% across the southeast half of the forecast
area. Trough axis digs into the eastern CONUS Saturday as the front
pushes farther offshore. Large scale confluence behind the trough
axis will allow strong Canadian high pressure to plunge southward
into the Midwest, nudging eastward into the Mid-Atlantic region. The
result will likely be drying conditions Saturday. Highs in the mid
to upper 30`s. Expect dry conditions Saturday night, but will keep
mention of slight chance POPs to account for the uncertainty.
Thereafter, all guidance in good agreement with building cold
Canadian high pressure into the region Sunday. The result will be a
cold/dry day with highs in the low to mid 30`s. Teens to low 20`s
forecast Sunday night. High pressure prevails Monday with highs in
the 30`s.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Mainly IFR/LIFR conditions anticipated through the 18Z TAF period,
as a pair of shortwave trofs move through the region. First system
will exit the region over the next few hours, temporarily ending
the steady rain, but maintaining low ceilings, and some
fog/drizzle. KECG is closer to the warmer air with the initial
shortwave, and have allowed their conditions to be mainly
VFR/MVFR, through 23Z. Ceilings and visibilities may actually
drop further after 05Z tonight (to 100-200 ft/1 mile or less), as
next area of rain/showers moves in, and stronger surge of warmer
air comes northward. Expect conditions to improve just after the
18z as drier air moves into the region from the southwest.
OUTLOOK...Building High pressure and fair weather return for
Wednesday (though some lows clouds and fog may still linger Wed
morning). Overrunning moisture will bring an increase in cloud
cover Thursday. Spotty light rain or snow is possible late
Thursday through early Friday, followed by dry weather Friday
night/early Saturday.
&&
.MARINE...
Latest surface analysis centers ~1019mb low pressure just offshore
of the Mid-Atlantic coast with high pressure over the Northeast.
The result is a north to northeast wind at 10-20 knots. Few gusts
to around 25 knots still observed in the northern coastal waters.
Seas range from 3-4 feet in the south to 4-6 feet in the north.
SCA headlines remain in effect north of Parramore Island. The low
lifts northeast of the region tonight as flow becomes north to
northeast at or below 15 knots. Onshore flow will keep seas 4-5
feet in the northern waters tonight. Fog will also be a concern
where the winds are light with visibilities dropping below 1 mile
in the Bay, lower James River, and coastal waters, where a dense
fog advisory is in effect through late morning Tuesday. This may
possibly need to be extended through Tuesday afternoon.
Another area of low pressure approaches the region
Tuesday as high pressure builds into southeast Canada. Flow
becomes southerly late tomorrow at 5-15 knots. Expect 5 feet seas
to persist through the day Tuesday in the northern coastal waters,
with 4-5 feet possible from Cape Charles Light to Parramore
Island. Will keep headlines north of Parramore and extend through
Tuesday night as guidance is in good agreement. The low pushes
offshore Tuesday night as the trailing front pushes across the
waters Wednesday. Flow becomes westerly Wednesday and the
northwesterly Wednesday afternoon behind the front. Seas subside
to 3-4 feet. Waves 1-2 feet. Expect a northwest surge Wednesday
night as low level cold air advection increases, with winds
increasing to 15-25 knots. Seas 3-4 feet and waves 2-3 feet.
Thereafter, high pressure slowly builds into the region through
the end of the work week as the frontal boundary stalls along the
Southeast coast. Extended winds and waves have been trended away
from the GFS/WaveWatch, due to inconsistencies in the guidance
compared to the preferred ECMWF.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Dense Fog Advisory until 10 AM EST Tuesday for ANZ630>632-634-
638-650-652-654-656-658.
Small Craft Advisory until 6 AM EST Wednesday for ANZ650-652.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ/LKB
LONG TERM...SAM
AVIATION...LKB/WRS
MARINE...JDM/MAS/SAM/WRS
Area Forecast Discussion
National Weather Service Bismarck ND
955 PM CST Mon Jan 2 2017
.UPDATE...
Issued at 950 PM CST Mon Jan 2 2017
Little change with this update other than to convert Burke and
Mountrail counties to a Wind Chill Advisory. Elsewhere, maintained
the Winter Storm Warning as gradient winds continue to slowly
increase with 0.5 km winds of 25-35 kts expected to continue
through the night. Thus, expect significant drifting snow to
impact travel sufficiently to continue the Winter Storm Warning,
especially with light snow continuing to fall.
UPDATE Issued at 650 PM CST Mon Jan 2 2017
Based on webcam trends through 0030 UTC, have converted most of
western North Dakota over to a Wind Chill Advisory. The Winter
Storm Warning remains in effect for central North Dakota. However,
portions of this will likely be converted to a Wind Chill
Advisory later this evening.
UPDATE Issued at 455 PM CST Mon Jan 2 2017
Quick update to begin the process of replacing Winter Storm
Warning and Winter Weather Advisory headlines with a Wind Chill
Advisory as visibility improves and snowfall decreases. This has
first been completed for Bowman and Slope counties based on webcam
trends through 2245 UTC.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 404 PM CST Mon Jan 2 2017
A winter storm continues to impact North Dakota and much of the
Northern Plains. Snow is expected to taper off through early Tuesday
morning.
Significant snowfall accumulations between 8 and 14 inches are
forecast for most of western and central North Dakota. Thus far,
totals between 6 and 10 inches have been reported in west/central
areas. Higher snowfall amounts of up to 14 inches are possible in
portions of Kidder, Stutsman, Wells, and Foster counties.
Responsible for the snowfall, a mid/upper level low has progressed
northeastward and strengthened through the day. Snowfall has
intensified with rates around 1 inch per hour or greater. Forecast
soundings indicate plenty of atmospheric moisture and lift in the
dendritic growth zone, which would support intense snowfall rates.
Snowfall intensity should begin to taper off in western and central
areas by late afternoon with light snow expected to linger through
early Tuesday morning. The 18Z HRRR along with the current suite of
short term high resolution models are indicating snowfall ending
around 03Z Tuesday. Though, we will currently maintain tapering
off snowfall in the forecast through 12Z Tuesday.
Wind gusts around 35 mph will accompany this system. Blowing and
drifting snow have created dangerous travel conditions. Visibilities
as low as a quarter of a mile have been reported, along with
significant drifts causing difficult travel.
After the storm, frigid conditions with dangerously cold wind chill
values are expected through much of Tuesday. Wind chill values near
30 below zero are forecast.
.LONG TERM...(Tuesday night through Monday)
Issued at 404 PM CST Mon Jan 2 2017
Arctic air will impact the Northern Plains through much of the long
term period. Below average temperatures and extreme wind chill
values are expected. Wind chill values between 25 and 35 below zero
are forecast with periodic wind chill values near 40 below zero
overnight Tuesday/Wednesday. Otherwise, look for a fairly dry
period with only slight chances for snow returning to the
forecast towards the end of the term.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 950 PM CST Mon Jan 2 2017
Widespread IFR conditions associated with a winter storm will
gradually improve to MVFR across the region tonight through
Tuesday morning from west to east as a winter storm departs the
region. Then very cold air with follow Tuesday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 6 AM CST /5 AM MST/ Tuesday for
NDZ003>005-011>013-019>023-025-034>037-042-045>048-050-051.
Wind Chill Advisory until midnight CST /11 PM MST/ Tuesday night
for NDZ001-002-009-010-017-018-031>033-040-041-043-044.
&&
$$
UPDATE...AYD
SHORT TERM...AC
LONG TERM...AC
AVIATION...AYD
Area Forecast Discussion
National Weather Service Denver/Boulder CO
850 PM MST Mon Jan 2 2017
.UPDATE...
Issued at 830 PM MST Mon Jan 2 2017
Latest observations and radar only showing some very light snow
over Western Larimer and Jackson counties but no snow further
south over the Interstate 70 cooridor through Summit county. The
jet core across Central Wyoming will continue to put far Northern
Colorado under favored ascent region of jet through the night
along with some banded snowfall possible. Given upstream
observations over Southwest Wyoming and Northern Utah expect a bit
better enhancement of snowfall over zone 31 through the night and
sections North of Rocky Mountain National Park. Forecast amounts
tonight look a bit over done and will lower a tad, especially in
zone 33 and 34. Will go 4-8 inches in zone 31 and lower amounts
further South.
As for lower elevations, stratus deck has developed over much of
the urban corridor but much of the far plains only have mid and
high level clouds for now. Could be a few flurries that try and
drift off the hills tonight and especially far northern areas
bordering Wyoming which is closer to the jet dynamics.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 201 PM MST Mon Jan 2 2017
The jetstream will remain over Colorado with a strong
west/southwesterly flow aloft over the state. No changes regarding
the current highlights for the northern mountains tonight through
Tuesday. The HRRR runs continue to show potential for locally
heavy bands of snowfall overnight. This enhancement is evident on
the composite radar mosaic this aftn, most areas focus on zone 31
and maybe 33. The first disturbance will gradually lift northward
tonight. The best window for snowfall will be tonight into
Tuesday morning with some decrease in moisture Tuesday afternoon.
The arctic front pushed through Denver this aftn, much faster than
any of the mdls suggested. Forecast soundings tonight show
shallow post frontal moisture around but limited moisture in the
mid and upper levels. As a result, slgt chc pops for snow in most
areas tonight and Tuesday morning. Could see better coverage north
along the Cheyenne Ridge in better proximity to the jet aloft.
Fcst temperatures for Denver around 25 degrees colder than today.
.LONG TERM...(Tuesday night through Monday)
Issued at 201 PM MST Mon Jan 2 2017
Strong NW flow will continue through Thursday over the state
bringing a moist flow over the mountains for an extended period of
time. This flow combined with decent lapse rates over the higher
terrain will bring snow showers to the mountains through Friday.
Winds over the higher terrain will gust up to 35 mph over the
higher passes WEdnesday that could cause some blowing snow. For
the plains moisture will extend into the northern portions of the
state and with favorable SE winds over the Cheyenne ridge some
light snow will be possible over the CO/WY border and south into
northern Weld and Logan counties Wednesday. Conditions should
remain dry over Denver on Wednesday with highs in the lower 20s
behind the arctic push earlier in the week.
Another push will drop south over the NE plains by Wednesday
evening increasing moisture and turning winds to the NE. This will
help to bring snow into Denver with deepening moisture profiles
and favorable upslope. The upper level jet will return on
Wednesday night into Thursday with the left exit region over the
plains. Model cross sections show areas that could be favorable
for CSI late Wednesday. This set-up could result in higher
snowfall amounts under localized bands on the plains. As of right
now looking at snowfall totals from Late Wednesday into Thursday
evening being from 2 to 5 inches on the plains with aforementioned
higher amounts possible under any developed bands. Temperatures
will continue to be below normal with highs Thursday and Friday in
the teens and 20s with single digits overnight.
Thursday and Friday the models start to differ on the placement of
the next upper level feature. The EC has the open wave dropping
out of the Pacific NW faster then the GFS which keeps it a tighter
low and doesn`t move it into the state until Friday night. Both
show some surge of moisture moving through Thursday night into
Friday so kept a chance in the mountains and a slight chance on
the plains. Temperatures will slowly bounce back on Saturday to
freezing with normal expected by the Sunday when ridging and high
pressure takes over.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 830 PM MST Mon Jan 2 2017
Stratus now solid over BJC/DEN, but still hasn`t made it into
APA. Given the thickenss of the high level cloudiness it is hard
to tell where the southern/eastern extent of the stratus is but
still think it will work into APA between 04-06z. Stratus may lift
a bit over night as low level flow turns a bit more southeast.
Could be some flurries but don`t expect accumulation due to
shallow depth of moisture.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM MST Tuesday for COZ031-033.
&&
$$
UPDATE...Entrekin
SHORT TERM...Cooper
LONG TERM...Bowen
AVIATION...Entrekin
Area Forecast Discussion...Updated
National Weather Service Billings MT
848 PM MST Mon Jan 2 2017
.UPDATE...
Weak shortwave moving through the area has generated a little
light snow. Accumulation has been limited, generally less than a
half inch. Shortwave will progress east and weaken overnight and
all models trend the precipitation downward. The HRRR has been of
little use with this event and have relied on the GFS which has
seemed to handle it rather well. Trimmed back pops over the west
as definitely see the back edge of the light snow on radar.
Maintained low PoPs through the night as another weaker wave was
moving through eastern Idaho and will swing across the forecast
area overnight, though models do not generate much QPF with it
all. Some light snow just now being generated at Livingston with
this energy, hence the reason to keep some PoPs in place. This
wave was weaker though, and am not anticipating as much coverage
on the light snow as with the current wave this evening.
Will not issue any wind chill highlights at this time. Winds were
below 10 mph in most locations. As surface high pressure settles
over the area, this should keep winds below criteria. Overnight
lows will be very cold and certainly wind chills will be low, but
do not think widespread 10 mph winds will be present (as is the
criteria for a wind chill highlight) through the night.
Temperatures have dropped off quickly at Miles City and adjusted
the low there down a few degrees. Lows tonight will be tricky and
based solely on when, and to what degree, the clouds will break
up. Models project that happening after the secondary wave later
tonight and this should allow forecast lows to be touched. Will
let the temperatures forecast ride, with the exception of some
downward tweaks here and there to better match current conditions.
TWH
&&
.SHORT TERM...valid for Tue and Wed...
Arctic high pressure will remain over the area at the surface through
the short term with very cold temperatures. Aloft will continue to
see Pacific impulses work over the top of the cold air for periods
of light snow.
A disturbance moving slowly over the area tonight will bump up northeast
winds a bit tonight, enhancing upslope winds and light snowfall as
it does so. Already seeing snow increase over western foothills
and should see this activity spread east as far as Rosebud county
by midnight. Snow accumulations with this activity will be
generally an inch or less with snowflake size being hurt by
temperatures pushing colder than favored dendritic growth zones.
Despite winds increasing just a bit tonight don`t think sustained
winds will be sustained over 10 mph across a broad enough area to
justify wind chill highlites tonight, though some areas may reach
criteria for a few hours. Overnight lows will be in the teens
below zero. Any breaks in the clouds will produce some -20 type
readings in lower valley locations.
Tuesday...Any accumulating snow will likely end early in the
morning across the area. Very light snow or flurries will probably
continue at times through Tuesday night. Temperatures will hover
around zero in the afternoon as core of the 1044mb surface high
settles over the area.
After another bitter cold night expect some sunshine of Wednesday
afternoon. Expect westerly winds to increase in the afternoon as
surface high begins to shift southeast. This will trend
temperatures warmer than Tuesday but will bring threat of
dangerous wind chill values more prominently into the forecast.
Doesn`t look like winds will support blowing snow to any extent
but drifting may be a problem. Chambers
.LONG TERM...valid for Thu...Fri...Sat...Sun...Mon...
Upper pattern keeps northerly flow over the area Thursday holding
cold surface air in place. By Friday flow begins to back to the
northwest which will bring some downslope influence to begin a
warming trend for the weekend as ridging builds into the area. As
Arctic air retreats will turn focus to strong winds developing
west of Billings possibly resulting in Blowing Snow/Ground Blizzard
issues Saturday and Sunday. Looks like another chunk of Arctic air
may drop back into the area Sunday night lingering through Monday
which would end strong wind/blowing snow threat but bring in a
chance for widespread light snowfall. Chambers
&&
.AVIATION...
IFR to occasional LIFR conditions continue across central
routes...including KBIL and KSHR...with low CIGS and VIS in snow.
Clearing has occurred in LVM...but another wave of snow is
expected tonight...bringing a return of IFR to LIFR conditions
across western routes. LIFR conditions also prevail over eastern
routes...including KBHK...with low CIGS and VIS in fog.
Otherwise...occasional MVFR conditions can be expected with
scattered areas of light snow across eastern routes. Conditions
will begin to improve by sunrise Tuesday. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 914/902 916/007 904/012 001/011 002/020 011/031 016/026
61/I 22/S 00/U 12/S 11/B 11/B 23/S
LVM 916/004 913/007 910/011 000/015 004/026 018/038 023/032
41/B 22/S 01/U 12/S 11/Q 22/S 23/S
HDN 914/901 919/008 913/011 901/011 903/016 004/029 013/025
62/S 22/S 11/B 12/S 11/B 11/B 23/S
MLS 918/903 916/003 908/012 902/009 905/017 004/022 008/019
41/I 22/S 11/B 22/S 11/B 11/B 23/S
4BQ 914/001 917/004 910/013 901/010 905/019 007/028 011/026
41/E 22/S 21/B 12/S 11/B 01/B 13/S
BHK 916/903 916/000 910/009 904/005 907/012 002/023 006/016
31/I 22/S 21/B 22/S 11/B 11/B 23/S
SHR 912/002 916/006 909/015 903/014 001/020 007/034 016/031
62/S 22/S 10/U 12/S 11/B 11/B 12/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Cheyenne WY
856 PM MST Mon Jan 2 2017
.UPDATE...
Issued at 851 PM MST Mon Jan 2 2017
Watching IR satellite imagery, cloud tops cooling in a band that
is moving from northern Colorado into southern Albany County at
this time. Talking with Albany Dispatch, they have already
received 4 inches of snow in the city of Laramie and with this
band moving directly over southern Albany County, decided to
upgrade the advisory to a warning for zones 115 and 116. Moderate
to heavy snow with 6 hour QPFs on the order of .20 to .30 inches
are expected through roughly 15Z, so they should get another 3-4
inches before all is said and done. Updates have been sent.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 232 PM MST Mon Jan 2 2017
Initial band of snow that moved across parts of the CWA this
morning has pretty much lifted northeast leaving just some snow
showers over mainly western and northern parts of the CWA this
afternoon.
Overall pattern will change little overnight through Tuesday with
a moist westerly flow across the CWA overrunning a cold surface
air mass. This will keep snow going over the higher mtns through
the day Tuesday with periods of heavier snow thus the winter storm
warning there looks in good shape with an additional 6 to 10
inches of snow tonight through Tuesday. Another ripple of energy
looks to pass across southern parts of the CWA later tonight into
Tuesday and should enhance snowfall for a time over adjacent lower
elevations around the mtns to the South Laramie Range so have
opted to post a winter weather advsy for late this evening
through Tuesday morning as 3 to 6 inches look a decent bet in
those areas...highest over the S. Laramie Range. Some snow should
also trickle east over the Cheyenne Ridge area into the far
southern Panhandle but amounts lighter there. Otherwise colder air
will filter into the CWA tonight as an arctic high settles down
the high plains with cold temperatures continuing Tuesday...likely
remaining in the single digits over lower elevations east of the
mtns through the day.
.LONG TERM...(Tuesday night through Monday)
Issued at 232 PM MST Mon Jan 2 2017
Rather complex pattern expected through the course of this week
with the Arctic frontal boundary stalled to our southwest while a
series of upper shortwaves move across the region in the west to
northwesterly flow aloft. We have high confidence that
temperatures will remain some 15 to 20 degrees below normal
for this time of year through at least Friday. Of lower
confidence is the timing of the shortwaves moving across and
timing of snowfall, especially towards late in the week. We have
a little more confidence with the GFS and ECMWF trending closer
in their solutions bringing a shortave across Wednesday into
Wednesday night...so we have a bit higher PoPs for snowfall along
the Colorado border westward into the mountains where greater
forcing will be at play. This week should see some significant
snowfall totals in the mountains given the setup with the frontal
boundary stalled to the southwest and a moist westerly and active
upper flow going. Given the large spreads of solutions in the
various model guidance for Friday, we kept PoPs somewhat low for
Friday with not much expected by Saturday, but that may trend up
as model solutions start to converge on a solution by mid week. By
the weekend the frontal boundary should start to retreat northward
and that will bring PoPs up again Sunday going into Monday for
portions of Carbon and Albany counties.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 419 PM MST Mon Jan 2 2017
Hampered some with loss of HRRR guidance, but do think lowering
ceilings will be the theme tonight as upsloping low level winds
are occurring. Looking at snow moving out of north central
Colorado this evening that will aid in lowering conditions as
well. GFS and NAM soundings also showing strong surface inversion
with low cloudiness in the inversion, so there is some confidence
in IFR/LIFR becoming widespread as the evening progresses.
&&
.FIRE WEATHER...
Issued at 232 PM MST Mon Jan 2 2017
Fire weather concerns nil for at least the next few days with
conditions remaining non-critical due to cold temperatures and
snow cover.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Storm Warning until 5 PM MST Tuesday for WYZ112-114.
Winter Weather Advisory from midnight tonight to noon MST
Tuesday for WYZ110-111-113.
Winter Storm Warning from midnight tonight to noon MST Tuesday
for WYZ115-116.
NE...None.
&&
$$
UPDATE...GCC
SHORT TERM...RE
LONG TERM...JG
AVIATION...GCC
FIRE WEATHER...RE
Area Forecast Discussion...Updated for Aviation
National Weather Service Peachtree City GA
710 PM EST Mon Jan 2 2017
.PREV DISCUSSION... /issued 1042 AM EST Mon Jan 2 2017/
UPDATE...
Currently getting a break from the rain across much of the area
but areas of drizzle and patchy dense fog remain in its wake.
Does not appear widespread enough as of now for a dense fog
advisory but will be covering with a special weather statement
through this afternoon.
Main change in the grids has been to back off considerably on the
anticipated pops through late afternoon. Latest HRRR keeps
activity in check until 21Z at which time widespread activity
moves back into the western portions of the forecast area. Still
looking for some type of line of storms to move through the area
around 03Z or so with isolated severe potential at this point.
Best instability is not in phase with the best shear but enough
overlap that we will still be concerned with damaging winds and
even an isolated tornado through the overnight hours.
Latest HRRR shows an additional 2 to 3 inches possible across the
southern tier. Will likely expand the Flood Watch eastward with
next update.
Deese
&&
PREV DISCUSSION... /Issued 430 AM EST Mon Jan 2 2017/
SHORT TERM /Today through Tuesday/...
Active pattern setting up for all of the area through early
Tuesday. 06z surface analysis shows the warm front extending form
Carrollton to FFC to Eatonton and finally beginning to make
northward progression. The northward advance thanks in part to a
potent shortwave located over central Texas that is moving
through the generally southwest mid level flow. South of the front
dewpoints have surged into the 60s and even touch the upper 60s
across SW GA. Strong area of moisture convergence extending from
SE AL northeastward across CSG and MCN this evening which combined
with PW 1.7 inches is increasing the flood potential...see
hydrology section for discussion on the threat and the new flood
watch.
SEVERE...
the main focus for the short term will be the severe
risk across a good portion of the state later in the day monday
through early tue am. The strong shortwave over central TX attm
swings east and takes on a slight negative tilt by 00z. Short term
hi res solutions prog the current activity to wane by late
morning followed by a resurge during the afternoon into the
evening. the rain shield surge will be important as to potentially
hamper and significant destabilization...however...models do
generally agree on decent sfc based cape and mu cape values of
700-1200 j/kg after 18z through around 03z ahead of the rain
shield. Do think the values drop in the models after that time as
a result of the feedback from the rain shield...but am not
completely sold on values going as low as 100 late in the evening.
particularly after the event last week which maintained 500 j/kg
well into the overnight with not nearly as impressive as a system.
While shear is impressive with deep layer values ranging from 35
kts to 50kts late in the evening...it does not look as impressive
as the previous system. 0-1 km helicity values are sufficient in
the 100-200 m2/s2 range throughout the event. All of this points
to the potential for severe storms including damaging winds and
tornadoes...particularly in the afternoon and late into the
evening Monday. SPC has placed most of the region in either a
marginal or slight risk with the highest tornado probs running
generally west of I75. If any tornadoes occur...they would be
embedded with a cluster of storms or within a line making them
likely rain wrapped.
30
LONG TERM /Tuesday Night through Sunday/...
Models start off in good agreement at the beginning of the
extended but differ quite a bit around day 5. The extended period
starts off dry as main frontal system exits the area Tuesday
afternoon and a drier airmass moves in from the northern gulf. After
the cold front moves east of the state...this is where the GFS and
ECMWF start to change course. The ECMWF sets up broad zonal upper
level flow keeping moisture streaming across the region through
day 7. The ECMWF also shows another frontal system pushing through
the region Friday with cooler temps and possible rain and light
snow amounts across north GA. The ECMWF then builds in a very
Strong high pressure ridge beginning sat morning keeping things dry
through the weekend. As for the GFS...once the front exits the
area Tues it brings in a high pressure ridge and dries things out
for a bit. There is a secondary wave that develops over the
central plains and sweeps across N GA Thu but another high
pressure ridge sets up Friday and keeps things dry through Sat
morning before another frontal boundary move into the region for
the weekend. With these to very different solutions to work with
have decided to keep in a slight chance of pops in the extended
for now and keeping in the chance for some mixed precip for the
end of the week and weekend. Will have to keep modifying the
forecast over the next few days and watch to see which models
begins to get a better handle on the situation.
01
HYDROLOGY...
Main rain axis across central GA shows up nicely on moisture
convergence progs. Do expect this area to wane as a weak impulse
in the flow is generally responsible for the enhancements in the
past several hours. Short term models diffuse this area later in
the morning as another area develops further West in AL and MS.
Rainfall has been efficient which would be expected given the 1.7
PW values and we have been approaching some 1" per hour rates in
some of the stronger storms. Given the potential for 2-4" more
rain and the 1-2" that has already fallen across SW GA...have
opted to add a Flood Watch through Tuesday AM. Will need to
monitor areas further north for possible expansion.
30
&&
.AVIATION...
00Z UPDATE...
Large area of rain with embedded thunderstorms slowly moving
east through Tuesday morning. Ceilings and visibilities mostly
ifr...but varying from lifr to mvfr. Expect ifr through the
night should prevail with some improvement after 16z Tuesday.
Winds east to southeast but variable and gusty in thunderstorms.
Winds becoming southwest around 08z and west to northwest by
afternoon.
//ATL CONFIDENCE...00Z UPDATE...
Medium on LIFR duration.
High on remaining elements.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 60 55 67 49 / 80 100 60 5
Atlanta 65 59 67 50 / 90 100 50 5
Blairsville 57 53 62 45 / 60 100 70 20
Cartersville 62 56 66 48 / 90 100 50 10
Columbus 70 62 69 52 / 90 100 50 5
Gainesville 57 55 66 50 / 80 100 60 5
Macon 70 61 71 52 / 90 100 60 5
Rome 63 57 66 48 / 90 100 50 10
Peachtree City 67 59 68 49 / 90 100 50 5
Vidalia 74 63 75 55 / 60 100 70 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday morning for the following zones:
Baldwin...Bibb...Bleckley...Chattahoochee...Crawford...Crisp...
Dodge...Dooly...Emanuel...Glascock...Hancock...Harris...
Houston...Jefferson...Johnson...Jones...Lamar...Laurens...
Macon...Marion...Meriwether...Monroe...Montgomery...Muscogee...
Peach...Pike...Pulaski...Schley...Stewart...Sumter...Talbot...
Taylor...Telfair...Toombs...Treutlen...Troup...Twiggs...Upson...
Warren...Washington...Webster...Wheeler...Wilcox...Wilkinson.
&&
$$
SHORT TERM...41
LONG TERM....20
AVIATION...41
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
948 PM CST Mon Jan 2 2017
.UPDATE...
A couple updates to the inherited forecast on this much more
tranquil weather evening across the state. Regional surface
analysis places a southward-surging cold front from the Oklahoma
Panhandle, to Enid, and near Ponca City this hour. Aloft, a 100+
kt extension of the subtropical jet is guiding an abundance of
high-level cloud cover across the region, and as such, have bumped
cloud cover wording up into the mostly cloudy category for most
of the area. As a result, also nudged low temperatures up a hair
in most locales as it looks like this cirrus shield will act to
mute radiational cooling overnight.
Finally, based on upstream observations, made a few adjustments to
the timing of the aforementioned cold front based largely on the
evening runs of the NAM and HRRR which are tracking this feature
well. We`ll show the initial wind shift moving into our far
northwestern counties around 6-7 AM, and then through our far
southeastern counties during the early afternoon. After
coordinating with surrounding offices, opted to introduce patchy
drizzle/fog wording to roughly the northern two rows of counties
coincident with the frontal passage Tuesday morning. The
combination of an already cool boundary layer, some moisture
advection out of southeastern Oklahoma, and a hint of lift below
850 mb should allow for the development of patchy fog/drizzle. Any
impacts should not last long as drier air starts filtering in.
Finally, could also see some very localized fog tonight near
Palestine where dewpoint depressions are just about nil, but its
highly localized nature and increasing high cloud cover precludes
patchy fog wording at this time. Updated products have been
transmitted.
Carlaw
&&
.AVIATION...
/ISSUED 543 PM CST Mon Jan 2 2017/
/00Z TAFs/
Concerns...Cold front arrives Tuesday with breezy north-northwest
winds and MVFR cigs.
Metroplex airports: VFR conditions are expected through late
Tuesday morning. Light southwest winds will become westerly
overnight, and then shift to the northwest Tuesday morning as a
cold front approaches. Wind speeds will pick up to 12-16 kts
around midday with some gusts near 20 kts. BKN high clouds are
expected through the night, and then MVFR cigs with bases between
1200-2500 feet are expected behind the front. With this TAF
issuance, will spread MVFR cigs across all the Metroplex airports
but will monitor trends in the event the low cigs shift more to
the east.
Waco airport: VFR conditions will prevail through the period with
high clouds expected through tonight. Light southwest winds will
become westerly Tuesday morning, and then northwesterly as the
front arrives around midday. Winds behind the front will be 10-15
kts. Some MVFR cigs may approach the airport near the end of this
valid TAF period but there is low confidence in the speed and
track of the low cigs at this time.
JLDunn
&&
.SYNOPSIS...
After an active night of weather to start off 2017, a majority of
the forecast period looks to be mostly dry. Today was likely the
last day of well above normal temperatures for most areas (there
are a few exceptions) at least over the next 5 days. Right now,
the chances for any sort of precipitation look to be on the low
side, but there are a couple of days we will need to monitor
closely.
&&
.SHORT TERM (Tonight through Thursday)...
Early afternoon surface analysis showed that west to northwest
winds continued to overspread much of North and Central TX. Looking
at the temperatures across the area, one would think that it was
early spring as opposed to the dead of winter this afternoon. IF
you`re a big fan of the cold, you`re in luck as a stout cold front
continues to slide southward through portions of southwest and
central KS and is expected to move through the area on Tuesday.
For tonight---some mid/high level clouds will slide southward
into the area from the northwest. This afternoon`s west winds have
likely instigated some good drying and temperatures after sunset
should plummet quickly with partly clear skies, decreasing winds
and low dew points. Unlike the past several nights, the low levels
look too dry to support any type of fog development, but we will
keep an eye on this low potential.
For Tuesday and Tuesday Night---the front will slide southward
through the northern two-thirds of North and Central TX as the
parent upper low continues to rocket eastward towards the OH River
Valley/Great Lakes region. While the air in the wake of the front
won`t be the coldest the region has experienced over the winter
2016-2017 season, it will still feel quite cold compared to the
past week or so. Temperatures will likely fall through the day
for most locations, with some areas down across
southern/southeastern zones remaining warm through the entire day
as southwesterly flow at the surface continues. Overall lift looks
to be quite meager with the passage of this front, but there
should be enough remnant low level moisture for some
stratocumulus. Breezy north winds will likely result in wind chill
values in the teens and twenties along the Red River to thirties
elsewhere come Tuesday night into Wednesday morning. Overnight low
temperatures into Wednesday morning are expected to fall into the
20s and upper 30s across the region.
For Wednesday and Thursday---Cooler conditions can be expected on
Wednesday as north winds continue to advect colder air southward
into North and Central TX. Fortunately, north winds should
diminish so apparent temperatures should not be quite as low as
Tuesday night. With the north winds and dry airmass, however,
actual air temperatures will fall into the low to mid 20s across
northwest zones to low to mid 30s elsewhere.
Things potentially get interesting on Thursday as another surge
of colder air slides southward. While most models have little to
no QPF or PoP, most models do hint at what appears to be modest
850mb frontogenesis. I do question the amount of available low
level moisture for precip given Tuesday`s FROPA, but the tight
packing of the isotherms coupled with some modest shear along the
deformation zone does suggest that there may be the potential for
some very light precipitation, mainly along I-20 and points
northward. There may not be a ton of assistance for lift on the
synoptic scale, so this lowers the confidence as to whether or not
precipitation will even occur. With the zonal upper air pattern,
however, I cannot completely rule out a weak perturbation rippling
through the mid-level flow aloft late Thursday into Friday. For
now, I`ll increase low and mid level clouds and introduce a
mention of snow flurries along the Red River. There will also be a
slight chance for rain down across far southeastern zones where
models do indicate enough moisture ahead of the cold front for
some very light rain showers. Otherwise, Thursday looks to be
quite cold for most areas though far southern/southeastern zones
may experience slightly milder conditions ahead of the shallow
cold airmass.
&&
.LONG TERM (Friday through Monday)...
Friday and Saturday---Model differences continue into the day on
Friday lowering confidence in the extended portion of the
forecast. The GFS quickly modifies the low level airmass as it
advertises a very stout surface cyclone across southwest KS. In
this solution, the resultant wind field draws a large quantity of
moisture over and eventually through the colder airmass resulting
in likely cloudy, foggy and warmer conditions on Friday. The GFS
has exhibited a little bit of run-to-run consistency in this
solution, but given that it stands alone compared to the ECMWF
and Canadian, I`m a little hard-pressed to side with it just yet
given that it may be difficult to overcome the cold/dense airmass
at the surface. The ECMWF and Canadian appear to offer more
plausible solutions and sweep the front clear through much of the
region with high pressure building in.
The resultant forecast for Friday and Saturday features cool
conditions with a slow warming trend into the heart of the
weekend. Chances will remain near zero during the weekend with
perhaps the next best chance coming early next week. The increase
in rain chances would also mean slightly higher temperatures as
low level warm air advection occurs.
24-Bain
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 49 59 34 46 30 / 0 5 5 5 5
Waco 46 68 36 49 30 / 0 5 5 5 5
Paris 47 59 33 45 28 / 0 5 5 5 5
Denton 44 56 28 45 24 / 0 5 5 5 5
McKinney 45 58 32 44 27 / 0 5 5 5 5
Dallas 50 60 34 46 31 / 0 5 5 5 5
Terrell 47 62 35 47 32 / 0 5 5 5 5
Corsicana 49 67 37 48 33 / 0 5 5 5 5
Temple 46 74 36 50 33 / 0 5 5 5 5
Mineral Wells 43 57 28 46 25 / 0 5 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
82/90
Area Forecast Discussion...UPDATED
National Weather Service Green Bay WI
827 PM CST Mon Jan 2 2017
New Information added to update section
.UPDATE...
Issued at 827 PM CST Mon Jan 2 2017
Waushara county air temp and wautoma hovering near freezing with
mixed pcpn. Added this county to the advisory.
UPDATE
Issued at 522 PM CST Mon Jan 2 2017
More organized banded mixed precipitation gradually expanding
across central Wisconsin late afternoon before the rest of the
area by early evening. Quick glance at ongoing raob shows no warm
layer aloft, with the exception at the surface, so pcpn will
likely start out as a rain/snow mix this evening for the non
advisory area, especially with any higher radar return regions.
Will watch temp trends across the southeast area of the advisory
area for a possible earlier cancellation, otherwise no changes at
this time. Dense fog developed over parts of far southwest
Wisconsin prior to the mixed precipitation earlier today, but then
diminished a tad with the pcpn. Could see a period of dense fog
over parts of central and east central Wisconsin toward early
morning as east winds subside.
&&
.SHORT TERM...Tonight and Tuesday
Issued at 231 PM CST Mon Jan 2 2017
The latest rap analysis and satellite/radar imagery show a cold
front positioned from central Minnesota to southern Lake Superior
early this afternoon. A series of weak shortwave impulses are
lifting northeast over the central Plains and northern Mississippi
Valleys, with light precip being reported on surface obs from
northern Iowa to central WI. Closer to home, 12z soundings and rap
analysis show a significant dry wedge centered around 850-800mb over
eastern WI, that has prevented the many returns on area radars from
reaching the ground. With southerly flow in this layer advecting in
higher dewpoints, should see this dry wedge erode by mid to late
afternoon over central WI and the southern Fox Valley, which then
should mark the arrival of the better precip. With wet bulbs still
below freezing, could see a dusting of snow over central WI by the
start of the evening. Precip and precip type trends are the main
forecast concerns in the short term.
Tonight...Broad southerly flow aloft will continue until late
tonight ahead of weak shortwave impulses lifting northeast across
the region. With dry air expected to erode, light precip will
spread from southwest to northeast across the region during the
evening. Models are more ambitious in the 12z cycle in regards to
the degree of saturation above -10C, which is often used as a bench
mark for ice crystals being introduced in the cloud. As a result,
potential for freezing rain looks rather limited this evening, but
does increase from southwest to northeast after about 08z tonight
when dry slotting arrives. Until this occurs, looking at an inch or
two of snow over central and north-central WI. Then a minor glaze
could occur on top of the snow late tonight. Though snow/ice totals
do not look quite as significant as before, the combo of snow/ice
could still create hazardous conditions on roadways, so no changes
to the current headlines. Over the Fox Valley and Lakeshore,
temperatures should remain relatively steady around 34-36 degrees,
which will likely lead to a rain/snow mix for the evening, changing
to all rain/drizzle overnight.
Tuesday...A strong shortwave will be pushing an arctic front across
the region from late morning through the afternoon. Will see gusty
west winds develop as cold advection ramps up behind the front.
May also see a few snow showers move into north-central WI late in
the day. Prior to this though, drizzle/freezing drizzle may continue
through 15z before the column rapidly dries out. Therefore, the end
time of the advisory remains on track. Sky conditions remain
problematic, however, and think there is potential for some clearing
to move into central and northeast WI for a period during the
afternoon. Temps will peak around late morning or midday, before
falling during the afternoon.
.LONG TERM...Tuesday Night Through Monday
Issued at 231 PM CST Mon Jan 2 2017
Much colder air will arrive Tuesday night, with H8 temperatures
dropping to near -20 C in northern WI overnight. Northwest flow
off Lake Superior and synoptic enhancement from a sharp upper
trof will generate numerous snow showers over far north central
WI, and bring up to 2 inches of accumulation to northern Vilas
county. The rest of the region should see flurries late Tuesday
night into Wednesday morning.
The cold air will remain over the region until the first half of
the weekend, with a reinforcing shot arriving in the wake of
another arctic frontal passage on Friday. Precipitation chances
will be minimal, except in Vilas county, where scattered snow
showers or flurries will occur from time to time. The main story
during this period is below normal temperatures, with the
potential for wind chill advisories over north central and
central WI, where wind chills of -20 to -25 F are possible Wed
ngt, Thu ngt and Fri ngt. There is some concern that abundant
cloud cover may limit the temperature fall Weds ngt and Thu ngt,
so have edged min temps up a degree or two.
Arctic high pressure is expected to slide east of the region
Sunday night into Monday, with increasing south winds leading to
significant warm air advection. Aside from moderating temps, there
is a small chance of precipitation. Confidence in the details is
low at this time.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 451 PM CST Mon Jan 2 2017
Cigs will lower to IFR levels over most locations
this evening as mixed precipitation spreads over the area. After a
brief mix at the onset, mostly rain is expected at MTW/OSH/ATW/GRB
and SUE. Freezing or frozen precipitation to the north and west of
the Fox cities toward Central and North Central Wisconsin. The
precipitation will diminish to freezing drizzle and flurries
toward early Tuesday morning. Gusty west surface winds and rising
ceilings expected after late Tuesday morning and especially
Tuesday afternoon with the start of colder air pouring into the
region.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 8 AM CST Tuesday for WIZ005-
010>013-018>021-030-031-035>037-045-073-074.
&&
$$
UPDATE.........TDH
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......TDH
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1053 PM EST Mon Jan 2 2017
.UPDATE...
Issued at 1050 PM EST MON JAN 2 2017
Showers are moving north across parts of the Cumberland Plateau
and into parts of the TN Valley with a few stray showers exiting
the northeast part of the CWA. As the upper level low/trough over
the TN Valley moves northeast into KY overnight, an area of
showers should move across much of the western, central and
northwestern parts of the CWA. However, convection over the
Southeastern Conus, especially the deeper convection over GA and
FL appears to be disrupting moisture transport into the area.
Thus, parts of the region nearer to the VA border may essentially
be split and receive very light rain amounts or even not receive
measurable precipitation at all tonight. For now held onto the
previous QPF and Pops, but confidence in this is lowest nearest to
the VA border.
UPDATE Issued at 745 PM EST MON JAN 2 2017
Hourly grids have been freshened up based on radar and short term
model trends as well as recent observations. Showers continue to
move north across parts of TN and northern GA and are nearing the
I 24 corridor. This is generally in line with the most recent
couple of HRRR runs as far as timing. Thus, as it stands now it
looks like showers will encroach on the Lake Cumberland area in
about 10 to 11 PM EST and the I 75 corridor around 11 PM EST to
midnight and overspread the rest of the area by about 2 AM EST.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 310 PM EST MON JAN 2 2017
19z sfc analysis shows a developing warm front over eastern
Kentucky linked back to low pressure in the deep south. Showers
and a few thunderstorms have broken out ahead of this to the south
of the area. Locally, low clouds cover much of eastern Kentucky
with some breaks occurring in the far east. This has helped
temperatures to climb into the low and mid 60s there while mid to
upper 50s hold on north of Interstate 64 where the fog is just now
clearing up. Dewpoints remain quite moist in the low to mid 50s
north to the upper 50s and low 60s south. Winds have switched to
the southeast for most of the area but are still rather light.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict a fairly strong southern
stream wave rolling into and through the Tennessee Valley this
evening and overnight. Though it is weakening as it passes, the
core of this feature will pass fairly close to the southern parts
of the forecast area keeping its dynamics in play through the
night. The pattern then flattens a bit as trailing energy passes
through East Kentucky and a northern stream trough to the
northwest starts to influence the region on Tuesday. This mid
level low to the north is exhibiting a fair amount of spread in
the models by mid week with the GFS quicker and a smidge stronger
than the ECMWF as it passes through the Great Lakes. By Wednesday
morning, the northern stream trough will be dominant through the
Ohio Valley with falling heights for Kentucky and much of the
southeast. Given the good agreement aloft early and some
differences late will favor a general model blend, but confidence
wanes after midday Tuesday on specifics. Have also leaned toward
the HRRR and NAM12 for details through Tuesday morning.
Sensible weather will feature a mild and quiet start to the night
across eastern Kentucky, but showers will push into the CWA from
the southwest for late evening with a few embedded thunderstorms
possible. As the sfc low works its way northeast along the Ohio
River tonight, widespread showers and a few thunderstorms will
overspread eastern Kentucky. Do expect the strongest storms to
stay to the south of the area given the limited instability this
far north. Will continue a small chance for thunder into the start
of the day Tuesday as the low starts to pull away. The track of
this sfc low will keep conditions quite mild through the day with
spotty showers continuing across the area into Tuesday night. CAA
in the wake of the low will then bring in cooler air toward dawn,
Wednesday, but not enough to worry about any mixed wx.
Once again started with the CONSShort and ShortBlend for most of
the wx elements with only minor adjustments in the near term for
current conditions and then to fine tune lows tonight and Tuesday
night. Also held off the PoPs initially this evening before going
100 percent for a significant amount of the time over much of the
CWA into Tuesday morning - higher than the blend.
.LONG TERM...(Wednesday through Monday)
Issued at 300 PM EST MON JAN 2 2017
The extended period looks to be active, with one weather system and
its associated rain showers exiting the area on Wednesday. The
weather should be quiet for awhile, from Wednesday afternoon through
early Thursday morning. The models are trying to bring a weather
system across the Ohio and Tennessee valley regions Thursday and
Thursday night, but the different models are still having a
difficult time converging on a common solution, so the forecast from
Thursday onward is still going to be low confidence. At this time,
have chosen to go with low precipitation chances across eastern
Kentucky Thursday through Friday, with another dry period forecast
from Friday afternoon through early Saturday morning.
The real uncertainty is expected for the weekend. The GFS model
currently has a potent winter storm with significant precipitation
moving across the Tennessee and lower Ohio Valley regions over the
weekend. The ECMWF model, however, is building a ridge across the
region, with dry weather on tap for the weekend. That being said,
decided to split the difference between the two models with slight
chance pops across the board. Some very light snow accumulations are
possible on Thursday and again Saturday through Sunday, should the
forecast verify. For now, will be going with lower PoPs, QPF, and
snowfall amounts than what the model blend gave, accounting for
uncertainty.
Temperatures through out the period are still looking to be well
below normal, especially from Thursday onward, when we are still
expecting daily highs in the 20s and 30s each day. Nightly lows are
still looking like they will be bottoming out in the teens and 20s
across the area. The warmest day in the period will be Wednesday,
when highs are forecast to max out in the 40s for most locations.
The area along and north of I-64 may see highs only in the upper
30s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 735 PM EST MON JAN 2 2017
A mix of MVFR and VFR cigs were occurring across the area this
evening. An area of low pressure will track into Central KY by
late tonight with a rather potent mid level shortwave also doing
the same. Showers should overspread the region between 3Z and 7Z,
with ceilings dropping back into the MVFR range as the atmosphere
saturates. Later tonight, between 8Z and 14Z as the low tracks
across the area and stratus builds down, further deterioration to
IFR is anticipated as fog will also be possible. A few
thunderstorms are also possible during that period. IFR should
linger in most locations through the end of the period, though
some locations may improve to MVFR. Winds will remain light
through the period - away from any limited thunderstorm activity.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JP
Area Forecast Discussion
National Weather Service Melbourne FL
932 PM EST Mon Jan 2 2017
.UPDATE...
Tonight...Mid level shortwave trough over the lower Mississippi
Valley is lifting out and the models show pre frontal convective
complex slowly weakening and staying well north of the local area. A
vort lobe is shown crossing the area but stability over land will
preclude any additional development, except over the Gulf Stream
like both the GFS and HRRR models suggest.
The other forecast problem is stratus/fog chances. The current
Canaveral profilers are showing low level winds around 25 knots.
This would favor stratus over fog, so our current forecast which
just has patchy fog looks sufficient.
Higher dew points tonight and stronger low level winds will moderate
low temps with current forecast in the mid-upper 60s looking good.
&&
.AVIATION...
MOS continues to show low stratus and fog especially KISM-KMCO-KTIX
northward. Think that with boundary layer flow forecast around 15
knots, we will mainly have IFR ceilings. Inherited TAFs introduced
LIFR ceilings at some sites and decided not to change, but kept the
emphasis more on low ceilings rather than visibility. The breezy
low level winds will break up the stratus shortly after sunrise but
there could be lingering MVFR ceilings until around 15z.
&&
.MARINE...
Tonight-Tue...GFS shows the pressure gradient tightening ahead of
the frontal boundary with MOS indicating southerly winds 15-20
knots. Canaveral profiler confirms that winds in the low levels
will support gusty conditions over the warmer Gulf Stream. Current
exercise caution statement for the offshore waters looks good.
&&
.CLIMATE...
Daytona Beach and Vero Beach should tie or exceed record high
temperatures on Tuesday.
Record Highs for Jan 3rd
Daytona Beach 83 in 1947
Orlando 86 in 1967
Melbourne 86 in 1967
Vero Beach 83 in 2006
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Lascody/Ulrich
Area Forecast Discussion
National Weather Service Marquette MI
612 PM EST Mon Jan 2 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 348 PM EST MON JAN 2 2017
WV imagery and RAP analysis indicated a mid/upper level trough from
east of Hudson Bay to the Pacific northwest resulting in sw flow
from the cntrl plains through the western Great Lakes. A vigorous
shortwave trough was located over the wrn Dakotas. Another was
lifting through se IA while the main srn branch shrtwv was moving
into the lower MS valley. At the surface, an inverted trough
extended into Mn from low pres over cntrl KS. Radars indicated
extensive returns over WI/MN into Upper Michigan supported by
WAA/285k-295k but with only patchy light snow observed.
Tonight, expect light snow to gradually spread to the northeast
across the cwa as the nrn plains shrtwv approaches and the WAA
pattern strengthens. However, with only weak to moderate isentropic
lift and a persistent 925-750 mb dry layer, the pcpn will be slow to
accumulate. Some light rain will also be possible over the southeast
near Lake Michigan. Only around an inch of accumulations is expected.
Tuesday, models suggest that as the deeper moisture departs the
probability of ice present will drop off enough while some light pcpn
persists for the potential of some freezing drizzle. Once the sfc
trough moves through and drier low level air moves in with the wrly
flow, any lingering pcpn will end. Although snow accumulations will
be light with the fzdz possibility and SPS was issued to highlight
potential hazard with slipper roads. By late in the afternoon, lake
enhanced snow will increase over the far west with low level conv
along the sfc trough and 850 mb temps dropping to around -9C.
.LONG TERM...(Tuesday night through Monday)
Issued at 407 PM EST MON JAN 2 2017
Long duration lake effect snow event expected for northwest to
west-northwest wind favored snowbelts, Tuesday night through Friday.
This will likely require a long duration headline. At this point,
have gone with a SPS to highlight the areas of concern due to initial
weak system sliding through the area during the short-term.
Broad upper level troughing will be in place across the Upper Great
Lakes region through much of the extended forecast with several
shortwaves rotating through the area. 850mb temperatures will
steadily cool from -15C to -18C Tuesday night to the -20C to -25C
range Wednesday through Friday. This will allow for more than enough
instability to create lake effect snow downwind of Lake Superior.
Tuesday night through much of Wednesday, northwest wind favored
snowbelts would be the most likely places to see lake effect snow as
low pressure slowly lift north and east of the U.P. High pressure at
the surface will slide into the Central Plains Wednesday night and
into the Mid Mississippi Valley by Friday. At the same time, the
aforementioned low pressure will continue the trek across into
northern Quebec. The movement and positions of these systems will
allow winds to become more westerly to west-northwesterly through
this time period, effectively shifting the heaviest lake effect snow
over the Keweenaw Peninsula and the far eastern U.P. for the last
half of the work week. This looks to be a fairly long duration lake
effect snow event with heavy snowfall totals expected across the
Keweenaw Peninsula through Friday. Many locations in the Keweenaw
will see snow totals in excess of a foot through the day Saturday.
One thing that may end up pulling totals back to some extent will be
the very shallow DGZ, which crashes down to the lowest couple
thousand feet late Tuesday night through the end of the work week as
the much colder air slides in aloft. Lake effect snow will
definitely be ongoing across the Keweenaw Peninsula, but the snow
ratios may be a little lower because of the shallow DGZ. Gusty winds
over the eastern Lake will lead to waves building to 9 to 12 feet
along the Lake Superior shoreline east of Marquette. This may lead
to some minor beach erosion at times Tuesday night into Wednesday
morning.
Models continue to differ on the timing of the southerly wind shift,
which will push the lake effect over Lake Superior; however, the
GFS/EC both have the southerly winds in place by late Sunday
afternoon into Sunday evening. Due to the continued lower confidence
in the timing of this wind shift, will continue to stick with a
consensus of the models for the Sunday into Monday time period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 612 PM EST MON JAN 2 2017
Conditions will continue to deteriorate as light snow moves into the
area overnight and conditions will drop to IFR/LIFR at all sites.
Conditions will improve slowly as the snow moves out Tue afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 348 PM EST MON JAN 2 2017
East to northeast winds of 15 to 25 knots will give way to w winds
to 30 knots Tuesday as low pressure moves through Lake Superior.
Northwest winds 20 to 30 knots Tuesday night into Wednesday could
reach gales to 35 knots at times over the east half of Lake Superior
Tuesday night into Wednesday morning as the deepening low exits east
of the lake. Northwest to west winds to around 30 knots will then
linger from Wednesday afternoon into Wednesday night before
diminishing to 15 to 25 knots Thursday into Friday. There is a
potential for heavy freezing spray Wednesday into Friday as Arctic
air moves over the area.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service New York NY
959 PM EST Mon Jan 2 2017
.SYNOPSIS...
Strong high pressure over New England will slowly retreats
northeast tonight. Low pressure develops off the mid atlantic
coast Tuesday then passes over the region Tuesday night. The low
will then move into the Canadian Maritimes on Wednesday. High
pressure will then build in through Thursday night, followed by
low pressure passing to the south Friday into Friday night, and
another high building to the west next weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Continuing to see just light echoes on regional radar mosaic,
KOKX and terminal doppler radars. Most locations reporting light
rain or drizzle with the exception of the northern zones where
some drier air continues to battle with low level moisture. This
is due to the some lingering cold air damming from the high
located over Maine. Have changed the forecast wording to chance of
light rain or drizzle for the rest of the night. HRRR and latest
high res NAM agree that any precip overnight will be spotty and
light.
Temperatures across inland sections have been running a few
degrees warmer than most high res model guidance as well as
statistical guidance. Will have to watch temperature trends
through the night. With lingering cold air damming across inland
locations, temperatures may fall close to freezing. Any
precipitation would then be in the form of light freezing rain.
Have already issued an SPS possibly icy conditions for Putnam,
northern Fairfield, northern New Haven, and northern Middlesex
counties where precipitation has been spotty the last few hours
with temperatures close to freezing. Temperatures elsewhere
across the interior have remained above freezing with not much
change so far. The SPS may need to be extended or expanded
overnight if temperatures fall overnight. However, latest high res
model trends actually show temperatures holding steady or even
rising a few degrees.
Low temps elsewhere tonight should be in the mid/upper 30s most
elsewhere, and near 40 in NYC and across Long Island where
maritime influence will be greatest via easterly flow between the
retreating sfc high and the sfc low off the Mid Atlantic coast.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
With the approach of the shortwave trough, one weak sfc low
should dissipate to the south on Tue, while primary low pressure
passes west of the Appalachians late Tue into Tue night, and a
secondary low develops over the Mid Atlantic region late day Tue,
and passes over Long Island Tue evening. Best chances for a steady
light to moderate rain will be Tue afternoon/evening ahead of the
secondary low. and easterly winds between this low and the
retreating high to the north could become brisk along the coast,
especially out east.
Highs on Tue should range from the upper 30s well inland, to the
lower/mid 40s elsewhere. Temps tue night should only drop a few
degrees due to cloud cover and lighter winds, remaining
above freezing throughout.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As the secondary low moves away toward the Canadian Maritimes,
drying conditions expected for most of Wed. A few showers may be
possible well inland.
High pressure builds in Wednesday night and Thursday with with dry
conditions continuing.
Confidence starts to decrease Friday through the weekend with models
diverging on solutions. The high moves east and low pressure over
the Gulf states moves off the Southeast coast and moves towards the
Northeast. The question is how far north the precip reaches. For
now, most of the precipitation stays south of the region. However,
will continue to mention at least some slight chance pops in the
forecast mainly across the far southeast portions of the CWA. High
pressure to the north should keep enough cold air in place to keep
any precipitation all snow.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
High pressure over Maine and the Canadian maritimes tracks slowly
east overnight into Tuesday as one wave of low pressure off the
DELMARVA coast tracks south of Long Island. Another wave of low
pressure approaches during Tuesday and tracks over the terminals
late in the day and into Tuesday evening.
Ceilings will be mainly IFR to LIFR through Tuesday, with brief
periods of MVFR possible. MVFR visibilities become IFR after 04Z
and will be variable in drizzle and fog into Tuesday morning.
ENE winds around 10 KTs become more easterly Tuesday and increase
with gusts to around 20 KTs developing during the morning.
.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.Tuesday night...IFR early, improving to MVFR as rain tapers off.
.Wednesday-Thursday...VFR.
.Thursday night-Saturday...Possible MVFR or lower in snow
showers.
&&
.MARINE...
Winds have increased on LI sound, especially on the western sound
noting Execution Rocks has gusted close to 25 kt. Have therefore
gone ahead and started the SCA here to match with the eastern
Sound with both zones now in effect continuing through Tuesday
evening. Winds will gradually increase on the Harbor and south
shore Bays by day break Tuesday morning. SCA conditions continue
on the ocean.
There is still potential for gales on Tue, especially out east;
in collaboration with adjacent WFOs maintained the SCA that was
already in effect, but if this signal continues with the next
forecast cycle a gale warning could be issued. Wave forecast
during this time is close to or no more than a foot higher than a
12Z WaveWatch/NWPS blend, with max ocean seas 10-11 ft, and
possibly reaching 5 ft east of Orient.
SCA conditions should continue on the ocean Tue night, mainly for
hazardous seas remaining above 5 ft.
Decent mixing should produce some SCA gusts Wednesday evening and
overnight. Then winds fall below SCA levels for the remainder of
the week and first half of the weekend. Seas however will remain
at or above 5 ft on the ocean through early Thursday. There is a
chance that seas east of Moriches remains up a bit longer. Seas
then fall below SCA levels Thursday night through Saturday night.
Winds and seas both build back to SCA levels on Sunday as low
pressure moves near the area waters.
&&
.HYDROLOGY...
Around an inch of rain is possible Tuesday and Tuesday night.
Otherwise, no other significant widespread precipitation is
expected.
&&
.TIDES/COASTAL FLOODING...
Continued onshore flow should bring water levels close to minor
flood thresholds on Tuesday along the shorelines of Staten
Island and Brooklyn, and south shore back bays of Brooklyn,
Queens, Nassau, and western Suffolk. No special products have been
issued to address this yet.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 AM to 6 PM EST Tuesday for ANZ338-
345.
Small Craft Advisory until 6 PM EST Tuesday for ANZ330-335-340.
Small Craft Advisory until 6 AM EST Wednesday for ANZ350-353-
355.
&&
$$
SYNOPSIS...BC/Goodman
NEAR TERM...Goodman/DS
SHORT TERM...Goodman
LONG TERM...BC
AVIATION...MET
MARINE...BC/Goodman/DS
HYDROLOGY...BC/Goodman
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Charleston WV
1005 PM EST Mon Jan 2 2017
.SYNOPSIS...
A cold front crosses late Tuesday. Cold air arrives Wednesday and
remains into the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 10 PM Monday...
Slowed the onset of pops by a few hours based on radar trends.
As of 125 PM Monday...
Low stratus and fog is hanging tough across southeast OH this
afternoon and also along the eastern slopes of the mountains.
As the low level flow backs around to the southeast and
strengthens...I expect gradual improving conditions in southeast
OH later this afternoon. Elsewhere, clouds bases will lift too
with the downsloping low level wind component into this evening.
There may even be some peaks of sun or filtered sun before sunset,
primarily along the I 79 corridor and parts of southwest Virginia.
For tonight...we await the arrival of the next system and slug of
moisture. The models are in good agreement taking the upper level
short wave and associated surface meso vortex from the lower MS
Valley this afternoon into the TN Valley this evening. Have timed
the arrival of showers based on the lasted HRRR and 4KM NAM. There
is enough elevated instability that a clap of thunder or two
cannot be ruled out, particularly across NE KY and along the OH
River late tonight. Otherwise, the area will get a good soaking
rain overnight with QPF amounts ranging from half and inch to an
inch. Temperatures overnight will remain very mild despite the
rains.
This system will move into the upper OH Valley Tuesday morning,
helping to drag a cold front through Tuesday evening. As such,
showers and perhaps some drizzle will linger for much of the day.
It will remain warm, however.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 320 PM Monday...
Winter finally arrives by Wednesday as an arctic front crosses
the area Tuesday night into early Wednesday. Models in fairly good
agreement on a band of relatively light rain showers proceeding
the front Tuesday night into early Wednesday. Rain showers taper
off fairly quickly behind the front, possibly ending as a little
snow especially in the mountains. Temperatures will be falling
through the 30s during Wednesday, and well down in the 20s
Wednesday night.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 325 PM Monday...
Another arctic front will move across the area Thursday with a
band of light snow expected. An upper disturbance following the
front will bring some more light snow Thursday night, but with
minor accumulation. The big question is for the weekend with a
storm system that tracks south of our area. Model consensus has
the track far enough south so that most of the snow with this
system will be to our south. So have coded up lower pops for snow
across the southeast half of the area for this weekend. Otherwise,
arctic air with well below normal temperatures will be in control
this period.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
As of 650 PM Monday...
Widespread IFR/LIFR has formed along the higher terrain, including
at site KBKW in southeasterly upslope flow. Expect this to linger
much of the night, although could see periods of brief improvement
to MVFR mainly after 09Z as rain moves into the region.
Otherwise, still expecting areas of MVFR across parts of southeast
Ohio and northeast KY for much of the evening, with mainly VFR
across WV lowlands including at sites KCRW and KCKB.
Rain will quickly overspread the region after 09Z, with widespread
MVFR and local IFR conditions developing. Bulk of rain will move
out of the area after 15-18Z, however, the potential for
widespread IFR and local LIFR cigs exists at all TAF sites for
much of the remainder of the TAF period.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Timing of any improvement in flight
conditions across the higher terrain including at KBKW may vary
from forecast. Conditions on Tuesday may deteriorate quicker to
IFR/LIFR quicker than currently forecast.
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 TUE 01/03/17
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 H H H H H M M H M H M L
HTS CONSISTENCY H H H H H H H H M M L L
BKW CONSISTENCY M M M M L M H M M M H L
EKN CONSISTENCY H M H H M M M M M M M L
PKB CONSISTENCY H H H H H H H H M M L L
CKB CONSISTENCY H H H L H H H H H M H L
AFTER 00Z WEDNESDAY...
IFR may linger in the mountains into Wednesday.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...JMV/30
NEAR TERM...SL/30
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...SL