Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/07/20
AREA FORECAST DISCUSSION
National Weather Service Albany NY
951 PM EST Thu Feb 6 2020
.SYNOPSIS...
Intermittent periods of rain and freezing rain will occur
overnight, turning to snow from west to east Friday morning into the
afternoon. The snow is expected to be heavy at times, especially
along and north of I-90. It will become windy and much colder Friday
night into Saturday. Mainly dry weather is expected for the weekend.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Winter Storm Warning for portions of the southern Adirondacks
and western Mohawk Valley through Friday night...
Winter Weather Advisory for areas mainly along and north of
I-88/I-90 through Friday...
Winter Weather Advisory for eastern Albany and Rensselaer
Counties until Midnight...
As of 945 pm EST...A full-latitude mid and upper level trough
centered over the MS River Valley will become negatively tilted
overnight with a strong sfc cyclone going through rapid
cyclogenesis moving northeast from the Southeast towards the
Piedmont Region overnight night. Strong water vapor transport
continues out of the Gulf. An inverted sfc trough coupled with
weak impulses in the southwest flow aloft bring intermittent periods
of rain and freezing rain. We have caught another lull in the
wake of one impulse in the last hour. However, we believe
another one will cause the pcpn to increase once again between
midnight and 3 am. We lowered the PoPs briefly, but then start
to increase them after midnight based on the 3-km HRRR and
upstream radar returns.
The temps are slowly creeping up in the Capital Region. KALB
finally hit 33F but the dewpt is 29F. The NYS mesonet shows
most temps in the 30-32F range in eastern Albany and Rensselaer
Counties, so we will keep the advisory going until midnight for
any patchy freezing drizzle or light freezing rain around.
Further north, shallow cold air remains in place with
north/northeast winds. Temps remain in the upper 20s to lower
30s.
A gradual upward trend is done tonight, though locaitons in the
Mohawk Valley north into the southern Adirondacks may never get
above freezing. We also added patchy fog to much of the forecast
area due to the adbundant low-level moisture and some melting of
the snow/sleet/ice.
Additional ice accretion of a light glaze in the Capital
District up to a quarter to third of an inch over the southern
Adirondacks/Lake George Region. Temps will be steady in the
upper 20s to mid 30s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
Winter Storm Warning for portions of the southern Adirondacks
and western Mohawk Valley through Friday night...
Winter Weather Advisory for areas mainly along and north of
I-88/I-90 through Friday...
On Friday, a shortwave rounding the base of the trough will
become negatively tilted as it progresses northward from the
southern Appalachians to southern New England. Models have been
consistent in depicting the potential for rapid cyclogenesis
attendant to this wave as it moves into the lee of the
Appalachians. For instance, several solutions show the central
pressure falling 20 mb in 12 hours, from ~990 to ~970 mb 06-18Z
Friday. The track of the storm has come into better agreement,
from south-central PA to near KPOU to the Maine coast 12Z Fri to
00Z Sat. Impressive dynamics attendant to the wave and surface
low will work into the area, resulting in a band of heavy
precipitation in the deformation zone which looks to set up from
the Catskills, Capital District, and southern Vermont and points
west. Strong frontogenesis in the 850 to 700 mb layer will be
occurring here, and could lead to a band of intense snowfall.
Temperatures will be rapidly crashing throughout the troposphere
as the low pulls away. One question for snowfall accumulations
is how much of the heavy QPF occurs as rain before turning to
snow, and how quickly can it accumulate on the relatively warm
ground. HREF probabilities for greater than an inch per hour
are mainly confined north and west of the Capital District,
which is where the highest probability of accumulating snow will
occur. A Winter Storm Warning was issued for the zones with the
highest combination of snow and ice, as there will likely be
some freezing rain ongoing over portions of the southern
Adirondacks/western Mohawk Valley after sunrise before turning
to snow. In the Winter Weather Advisory area, periods of
moderate to heavy snow are still possible in the afternoon, and
even briefly for areas outside of the advisory area.
The rain/snow transition zone is expected to be located in the
Glens Falls to Schoharie vicinity by around noon, and from
southern Vermont to the eastern Catskills by around 3 pm. There
could be a brief period of sleet/freezing rain with temps near
the surface possibly falling faster than aloft. As the wave
pulls away, strong westerly winds will develop in the afternoon
and evening, enhanced by the strong cold advection. This could
result in borderline wind advisory criteria, although mixing
depths will likely be hampered by cloud cover. Still, pressure
rises of up to 10 mb in 3 hours are modeled. The gusty winds
will exacerbate issues where there is snow and ice on the trees,
and could result in some power outages. The snow will be
tapering off from west to east roughly 4-7 pm, except lingering
over the western Adirondacks and southern Vermont due to
orographic lift. A much colder airmass will be filtering in
Friday night, with minimum wind chills ranging from the
negative to positive teens.
On Saturday, it will be mainly dry as high pressure briefly
builds in. A weak wave interacting with some lake-induced
instability may result in a few snow showers over the western
Mohawk Valley; otherwise, dry weather is expected. The pressure
gradient will relax, but it will still be a bit breezy with high
temps around 5-10F below normal.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
An active weather pattern looks to continue during the long range
period as a series of systems affect the region every two or so days.
High pressure will remain overhead for Saturday night which will
result in a mainly clear sky and bitterly cold night. Lows are
expected to range from -10 F across the northern Adirondacks to the
mid-teens across the mid-Hudson Valley.
As the surface high pushes off the coast on Sunday, an upper-level
shortwave and warm air advection will bring the return of clouds and
perhaps a few flurries. Little if any accumulation is expected with
this activity.
The southwesterly warm air advection flow will continue Sunday night
ahead of the next system set to arrive on Monday. This will result
in a milder night Sunday night and a milder day on Monday.
Precipitation is expected to begin as snow late Sunday night before
changing to rain in most locations on Monday. Precipitation may
remain all snow across the Adirondacks.
This system and associated cold front will push through the area
Monday evening and stall somewhere across the mid-Atlantic on
Tuesday. The next upper-level trough reaches the Great Lakes late
Tuesday into Wednesday as a surface low attempts to form along the
stalled front to our south. These two features may collide across
our region late Tuesday into Wednesday with another round of
rain/snow.
Yet another system may arrive on Thursday; however, there are widely
variable model solutions on this. Went with a blended approach for
this update which led to chance PoPs for more rain/snow.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
An inverted trough and a low pressure system will continue to
bring mixed precipitation to eastern NY and western New England
tonight through tomorrow.
Widespread IFR and low MVFR conditions continue to impact
KGFL/KALB/KPSF/KPOU tonight. Light freezing rain and drizzle
continue to impact KALB/KGFL/KPSF this evening with IFR and
periodic LIFR conditions, especially in terms of cigs and
sometimes vsbys. KPOU is above freezing and has had some
IFR/MVFR conditions with rain.
Expect widespread IFR/low MVFR cigs/vsbys overnight with some
lapses to LIFR. The ptype should transition to plain rain at
KALB/KPSF between 04Z-08Z/FRI. KGFL will likely have -FZRA/-FZDZ
until possibly 12Z-14Z, where a brief period of rain occurs, but
then a deepening sfc low will pass north of KPOU drawing in
colder air transitioning all the rain to sleet/fzra and then
snow at KALB between 17Z-20Z/FRI. Expect conditions to remain
IFR into the afternoon. Widespread IFR/low MVFR will persist the
duration of the TAF cycle.
KPOU will continue to have rain with IFR conditions rising to
MVFR briefly in the afternoon, before a rain/snow mix could move
in between 22Z/FRI to 00Z/SAT and a PROB30 group was used to
for now.
Winds will be light from the north/northeast to east at 4-6 kts
tonight, and the shift to the northeast to southeast at less
than 10 kts toward daybreak. The winds will increase quickly
from the west/northwest at 10-16 kts shortly before or just
noontime, and further strengthen from the west/northwest at
15-22 kts with some gusts 30-35 kts at KALB/KPSF/KPOU between
19Z/FRI and 00Z/SAT.
Outlook...
Friday Night: Low Operational Impact. Breezy. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: Low Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. Slight Chance of SHSN.
Sunday Night: Moderate Operational Impact. Likely SHSN.
Monday: High Operational Impact. Likely SHRA...SHSN.
Monday Night: Low Operational Impact. Slight Chance of SHRA.
Tuesday: Moderate Operational Impact. Chance of SHRA...SHSN.
&&
.HYDROLOGY...
Precipitation will increase in coverage tonight, becoming
moderate to heavy Friday morning into the afternoon. Rain and
freezing rain will turn to snow from west to east. Total QPF of
0.50 to 1.25 inches is expected through Friday evening, lowest
south and highest north. The heaviest precipitation is expected
where temperatures are not likely to be much above freezing, so
hydro issues are not anticipated.
Mainly drier and much colder weather is expected over the
weekend, allowing for rivers and streams to recede and potential
build ice.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory from 1 PM to 10 PM EST Friday for CTZ001-013.
NY...Winter Weather Advisory until 7 PM EST Friday for NYZ039>041-
043-047>051-082>084.
Winter Storm Warning until 10 PM EST Friday for NYZ032-033-038-
042.
Winter Weather Advisory until midnight EST tonight for
NYZ052>054.
MA...Winter Weather Advisory until 7 PM EST Friday for MAZ001-025.
VT...Winter Weather Advisory until 7 PM EST Friday for VTZ013>015.
&&
$$
SYNOPSIS...Thompson/Wasula
NEAR TERM...Thompson/Wasula
SHORT TERM...Thompson
LONG TERM...Rathbun
AVIATION...Wasula
HYDROLOGY...Thompson
Area Forecast Discussion
National Weather Service Binghamton NY
1006 PM EST Thu Feb 6 2020
.SYNOPSIS...
A rapidly developing low pressure system will bring a wintry mix
changing to snow tonight through Friday. Several inches of
snow is expected in Central New York through Friday. Steadier
snow tapers off Friday afternoon, before lake effect snow
showers kick in southeast of Lake Ontario late Friday.
&&
.NEAR TERM /THROUGH FRIDAY/...
With the 18Z model guidance and some of the 00z model guidance
such as the NAM and HRRR some trends are becoming more apparent. The
18Z RGEM/00z NAM appear a bit overdone with snow banding having
almost 1 inch of QPF centered from Tioga to Chenango county
late tomorrow morning in a six hour period. However, the
possibility of an intense snow band leading to dangerous travel
is increasing from the mid-morning to early afternoon hours.
The latest Snow Banding tool from FSU indicates frontogenesis
supportive of snowfall rates of 2 to even perhaps 4 inches per
hour under the band for a few hours.
The location of this snow band is still somewhat uncertain as
any deviation in the expected low track could lead to altered
snowfall totals with the next update. Some modeling is also
keying on two different bands a weaker one from Ithaca to
Syracuse around mid-morning then another one from across NE PA
into the Catskills. This possibility appears less likely at this
time, particularly with the less than reliable track record of
the GFS.
Model consensus is shifting to the band having more of
an impact further southeast into the Souther Tier and perhaps
Bradford PA than the previous update. As a result, portions of
the southern Finger Lakes and Southern Tier have been upgraded
to a winter storm warning. Based on the trends so far tonight
the warning may need to be expanded into Otsego and Broome
counties as well.
515 PM Update:
Temperatures continue to run at or just below freezing at many
locations across the western portions of the area. Some light
freezing rain/freezing drizzle as been reported at several
locations across these areas. Therefore, made adjustments to
hourly temperatures for this evening and increased coverage of
freezing rain/freezing drizzle somewhat. Also issued an SPS to
address potentially slippery conditions on untreated surfaces
this evening in these same areas. Otherwise, the forecast
remains on track and the previous discussion remains valid.
Previous Discussion:
Temperatures continue to be the main forecast challenge this
afternoon, as cold air at the surface continues to be locked in
across a good portion of the area, especially in Central New
York. As a result, some light freezing rain and freezing drizzle
has lingered a bit longer than expected across portions of the
Finger Lakes and northward towards the Syracuse area and towards
the Tug Hill. At this point, expecting temperatures to remain
fairly steady across these areas the remainder of this afternoon
and into this evening, allowing for an additional glaze of ice
accumulation.
Further south and east, temperatures are above freezing and
therefore any light precipitation the remainder of this
afternoon and this evening will likely be in the form of rain.
Conditions really begin to go downhill tonight as a strong and
rapidly deepening low pressure system moves up the Appalachians
and to the Hudson Valley by midday Friday. 12Z model consensus has
indicated that this storm will be deeper/stronger than previous
model runs, potentially near 970mb as it will be situated over
the Hudson Valley midday Friday.
Frontogenesis axis at the mid levels appears to set up right
over the Finger Lakes through NY Thruway, with dynamic cooling
changing rain/freezing rain to heavy snow late tonight-early
Friday. The axis may pivot into the Twin Tiers for a time early-
to-mid Friday before precipitation begins to take on a more
showery nature, and lake-enhanced for that matter southeast of
Lake Ontario late Friday into Friday night. The exact
positioning of this band is what remains somewhat uncertain, as
a small shift west or east from the current forecast can have a
significant impact on overall snowfall totals. Opted to upgrade
the Winter Storm Watch to a Winter Storm Warning for Seneca,
Cayuga, Tompkins, Cortland, Onondaga, Madison, and Oneida
counties, as this is where the greatest confidence is for higher
snowfall totals, mainly 6 to 9 inches with locally higher
amounts possible. Further south and east, Winter Weather
Advisories will be in effect for generally 4 to 7 inches of
snow. Potential expansion of the Winter Storm Warning will be
re-evaluated in future forecast updates as updated high-res
model guidance continues to come in. No headlines have been
issued for Sullivan, Pike, Southern Wayne, Lackawanna, and
Luzerne counties as any snowfall accumulations will likely be
minimal in these locations (generally 1 to 3 inches, with some
areas seeing less than an inch).
It is important to note that this will be a high impact system
for Central New York, as most of the snow will fall within a 6-8
hour period Friday morning with snowfall rates of 1 to 2 inches
per hour in the heaviest snow bands. This will be a rather
large concern for the morning commute. Heavy snow combined with
gusty winds may also cause scattered power outages. Snow tapers
off Friday afternoon, but transitions to lake effect snow
showers southeast of Lake Ontario.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Lake effect snow showers will set up Friday night and should
persist into early Saturday afternoon. However, high
pressure/ridging pushes in from the west and moves over Central
NY by Saturday evening and this will bring an end to any
lingering lake effect snow showers. Skies clear out Saturday
night and with a fresh snow pack temperatures should drop below
zero across Northern Oneida County and to near zero to single
digit readings across Central NY and into the Catskills.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
After a quiet and seasonable Sunday, a lake cutter approaches
the area. Surface low track is from lake Huron then up the St
Lawrence valley on Monday. This will bring snow to the area
initially, followed by mixed precipitation Monday as warmer air
is dragged into the area. Best chance of a full change over will
be over NEPA while the Tug Hill may remain as all snow.
Tuesday features another low, this time zipping up the east
coast. Mild air left in place may result in rain of mixed precip
at the start, turning to snow as colder air moves in behind the
low as it moves into New England. Brief lake effect snow showers
are likely Wednesday before high pressure builds in late in the
day.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
IFR conditions are forecast for much of the next 24 hours. Light
fog and patchy drizzle or freezing drizzle will keep clouds
between 500 and 1500 feet this evening with visibilities between
2SM and 5SM.
A mix of freezing rain, sleet, and rain will slide across the
terminals overnight. Ceilings will drop to between 200 and 1000
feet. As colder air moves into the region early Friday, snow
will develop and become heavy at times. Widespread LIFR
conditions are likely.
Outlook...
Friday night...Lake enhanced snow showers and occasional
restrictions for KSYR-KRME; possibly at times KITH-KBGM.
Saturday through Monday... Occasional snow showers with
restrictions, mixed with rain on Monday.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 1 AM to 5 PM EST Friday for
PAZ038>040-043.
NY...Winter Weather Advisory from 1 AM to 5 PM EST Friday for
NYZ046-056-057.
Winter Storm Warning until 4 PM EST Friday for NYZ023-024-055.
Winter Storm Warning until midnight EST Friday night for
NYZ009-016>018-025-036-037-044-045.
Winter Weather Advisory until 1 PM EST Friday for NYZ015-022.
&&
$$
SYNOPSIS...BJG
NEAR TERM...BJG/MWG
SHORT TERM...MPK
LONG TERM...DGM
AVIATION...DJP
Area Forecast Discussion
National Weather Service Bismarck ND
934 PM CST Thu Feb 6 2020
.UPDATE...
Issued at 934 PM CST Thu Feb 6 2020
Latest fog/stratus imagery loop show clearing continuing to push
from northeast to southwest, with the leading edge now nearing
locations along and east of the Missouri River. The NAM and RAP13
925mb-850mb are the closest models to reality when initializing
with the current satellite and surface observations. Over the next
few hours, have essentially cleared out the sky and lowered
temperatures significantly along and east of a line from near
Crosby to New Town, and from Hazen to Linton. Although there is
another batch of stratus just east of Jamestown that will roll
into the James River Valley 04z-09z then clearing.
With this update, also have opted to issue a wind chill advisory
for Rolette County until 15z Friday as they are and will continue
to meet wind chill advisory until shortly after daybreak Friday.
This also blends in well with the wind chill advisory already in
place across northeast North Dakota.
UPDATE Issued at 521 PM CST Thu Feb 6 2020
Latest surface map shows the surface-850mb cold front/isotherm
packing/baroclinicity residing over southwest North Dakota.
Reflectivities have been increasing over the past hour per Bowman
radar. SPC mesoanalysis indicates an area of low level/925mb
frontogenetical forcing with additional forcing from a mid
level/700mb over eastern Montana sliding atop the low level front.
Expect forcing at its peak now, then on the decrease shortly
after 00z Friday as the mid level shortwave shifts into northwestern
South Dakota by 03z Friday. Current forecast has the southwest
PoPs handled well and no changes needed. Clearing continues to
slowly nudge back to the southwest from the Turtle Mountains. Feel
the HRRR has the best initialization on this and would anticipate
some clearing to push into the James River Valley, but fall short
of reaching Bismarck at this time. Low level winds back from
north-northeast to the northwest 12z-15z Friday, and in doing so,
will counteract any clearing trying to progress in from the
Turtle Mountains. Otherwise, with a clear sky in the Turtle
Mountains, wind chills will be monitored closely tonight. As of
now, wind chills at Rolla are at 16 below zero.
&&
.SHORT TERM...(This evening through Friday)
Issued at 308 PM CST Thu Feb 6 2020
The short term forecast is highlighted by light snow accumulations
in western North Dakota, and very cold morning temperatures in the
north central.
The base of a longwave trough was located over the south central
CONUS, with ridging over the Pacific and northwest flow aloft over
the Northern Plains. At the surface, a slow-moving cold front was
draped from Beach to Linton. A weak area of low-level
frontogenesis and warm air advection behind the frontal boundary
is continuing to produce light snow across much of central North
Dakota this afternoon.
Although snow is expected to taper off this evening across central
North Dakota, a weak upper-level impulse has already started
producing snow in western Montana and far southwestern North
Dakota. This is likely to continue tonight, with an additional 1
to 2 inches of snow for the western part of the state. Locally
higher amounts are possible in the far southwest with a potential
for banded snow, due to a band of low-level frontogenesis
collocated with strong lapse rates.
Clouds are expected to clear in north central North Dakota tonight
as surface high pressure moves in. Radiational cooling coupled with
cold air advection behind the front will drop overnight low
temperatures much lower than they have been lately. Forecast lows
are currently in the -10 to -15 range for Bottineau, Rollette, and
Pierce Counties, with lows near zero and colder along and north/east
of the Missouri River.
Light snow could linger in the western half of the state through
much of Friday, although no accumulation is expected. As the high
pressure slides through eastern North Dakota, expect highs
temperatures ranging from the single digits in the east to the
lower 30s in the west.
.LONG TERM...(Friday night through Thursday)
Issued at 308 PM CST Thu Feb 6 2020
The extended forecast is highlighted by more snow in southwest North
Dakota Saturday night, with more precipitation possible midweek
and colder temperatures on the horizon.
Quiet weather on Saturday ahead of a shortwave moving through the
broad northwest flow that will bring more snow to the region. A
surface low is projected to slide to our south with a baroclinic
zone setting up on the northern side of the low. This, along with
large- scale ascent aloft, may produce an area of higher snow
accumulations. Model guidance is quite variable in QPF and thus
snow amounts with this system, which will be dependent on where
exactly this baroclinic zone ends up. GEFS/WPC plumes have a wide
range of solutions but for our forecast area, the highest snow
amounts are expected in far southwestern North Dakota, with
amounts decreasing to the north and east. For QPF amounts with
this update, opted to blend the previous shift`s amounts with the
latest WPC guidance. Due to it being a banded snow event with
amounts quickly decreasing through the forecast area, it`s not
surprising to have fluctuations in how much and where the snow is
expected, but we wanted to keep some continuity to the forecasted
snow totals.
Snow should end quickly on Sunday before a few days of quiet
weather and high temperatures in the 20s and 30s with northwest
flow aloft. The potential exists for more precipitation mid-week,
but model guidance has been too inconsistent to have much
confidence in anything specific. However, there is agreement in
both model guidance and CIPS analogs that temperatures will drop
well below average by the end of next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 934 PM CST Thu Feb 6 2020
MVFR to low VFR cigs can be expected this taf period at KXWA and
KDIK. Clearing continues to push from KMOT and on into KBIS by
06z. Expect KJMS to clear after 09z Friday. Flurries and/or a
period of light snow also can be expected KDIK through Friday
afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until 9 AM CST Friday for NDZ005.
&&
$$
UPDATE...KS
SHORT TERM...MJ
LONG TERM...MJ
AVIATION...KS
Area Forecast Discussion
National Weather Service Boston/Norton MA
1032 PM EST Thu Feb 6 2020
.SYNOPSIS...
Low pressure in the Mississippi Valley will intensify into a strong
storm as it tracks across New England Friday. This will bring a
period of rain tonight into Friday, changing to snow across interior
Massachusetts before ending late Friday or Friday evening. The storm
will also result in strong to damaging wind gusts Friday afternoon
and evening as the storm exits. Expect dry and cold conditions to
prevail Saturday as high pressure builds across. Quick moving
weather systems may bring periods of light rain and/or snow at times
from Sunday through Thursday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Tweaked the forecast this evening, mainly temperatures and
timing of precipitation. For temperatures, preferred the ideas
presented by the 06/18Z 3-km NAM and the latest few runs of the
HRRR, which held temperatures closer to freezing across the
northern tier of MA through much of tonight. Thus, a slightly
higher risk for additional freezing rain/drizzle later tonight.
Since this is where the present Winter Weather Advisory exists,
will let that continue as is.
Latest NationalBlend and HRRR guidance also picked up on current
relatively dryness across much of southern New England. While
not a widespread rainfall, trace precipitation reports indicated
plenty of lingering drizzle. Expecting measurable rainfall
chances to increase once more after midnight.
Previous Discussion...
Next area of steady rain lifting north from the Mid Atlc
region. Potent mid level shortwave rounding the base of a deep
and amplified trough with right entrance region of upper jet
will result in deepening low pres as it moves into PA late
tonight. Strong low level jet develops ahead of this system.
While the axis remains offshore, enough convergence combined
with deep and anomalous PWAT plume, 3-4SD above normal, will
bring widespread rainfall to SNE tonight. A period of heavy rain
is possible along the south coast and Cape/Islands closest to
the low level jet. There is some instability noted above the
frontal inversion over the southern waters late tonight and
toward daybreak so can`t rule out a t-storm over Nantucket and
adjacent waters. Potential for 1-2 inches rainfall Cape/Islands
tonight with amounts dropping off to the north, decreasing to
around 0.25" in northern MA.
Temps are mostly above freezing, but still near and a bit below
32F over the higher elevations in interior MA. Most of the hi-
res guidance keeps temps in the elevated terrain near freezing
through the night as light north persists so pockets of freezing
rain possible. As a result will extend the winter weather
advisory through tonight for higher terrain in MA. Additional
ice accretion will be less than one tenth of an inch.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
Highlights...
* Period of strong to damaging wind gusts mid/late afternoon,
strongest near the south coast
* Rain changing to a period of snow mid/late afternoon in western
and interior northern MA before ending
Rather potent storm will be tracking across interior SNE, deepening
below 970 mb as it moves across the region and to the NE. The main
concern with such an anomalous and rapidly deepening low pres is
strong to damaging winds as it lifts to the north. 60 to 75 kt low
level jet with strong cold advection behind the storm and
isallobaric contribution from a very impressive pressure fall rise
couplet gives high confidence in damaging west wind gusts from about
mid afternoon into Friday evening as the storm lifts to the north.
Expect the strongest gusts, 60+ mph near the south coast and
Cape/Islands. This is where temps should briefly spike well into the
50s which will enhance boundary layer mixing. We issued a high wind
warning for this area, with a wind advisory for 50-55 mph gusts for
much of the rest of central/eastern MA and Rhode Island. The
advisory may eventually need to be expanded across rest of SNE.
While the strongest winds are expected mid/late afternoon, may see
an initial surge of strong SW gusts along the south coast early
afternoon.
Mid level low will be tracking well to the north across northern NY
and northern VT. This will result in dry slot moving up across New
Eng during the morning which will bring a temporary lull in the
rainfall. Then what`s left of the comma head will bring another shot
of precip, especially to central and western MA during the
afternoon. Ptype starting as rain but as colder air deepens, expect
a change to snow for interior northern and western MA toward mid
afternoon. A coating to 2 inches possible before the snow ends in
the early evening. By the time the colder air arrives in the coastal
plain, it will likely have dried out so not expecting any snow here.
Temps tricky as warm front will be lifting north across SNE with
temps warming well into the 50s to the south of the boundary and
remaining in the 30s/low 40s to the north. Best chance of seeing 50s
will be across RI and SE MA for a brief time in the afternoon.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Highlights...
* Dry and cold Saturday
* Light snow/rain showers possible sunday
* Next widespread rain/high elevation snow system comes Sunday
night/Monday
* Periodically unsettled weather and mild temperatures continue
through next week.
Details...
Friday night...
The main takeaways for Friday night will be drying out, dropping
temps, and decreasing wind. By the overnight hours the last vestiges
of snow will be lingering over the Berkshires, with dry weather
elsewhere as the low moves past Nova Scotia, taking the moisture
with it. Behind it and behind the cold front CAA will be in full
force bringing 850 mb temps from ~0C Friday afternoon down to
-15 C by Saturday morning. Given this pattern we can expect a drop
in low temperatures of about 10 to 15 F from Friday morning to
Saturday morning...in the teens and low 20s. This puts us right
around normal for this time of year...something we haven`t been able
to say much in the past month. Winds will be diminishing after
peaking in the late afternoon/evening along the southeast coast as
the low quickly exits and the pressure gradient on the backside
begins to relax. We`re looking at wind gusts 40-45 kts before
midnight, coming down to around 30 mph for the early morning hours
of Saturday. Highest gusts will continue to be over southeast MA but
it will be windy everywhere as CAA promotes good mixing of 40-50 kt
850 mb jet.
Saturday and Sunday...
Saturday will be both the coldest and driest day of the extended
forecast as high pressure moves overhead. W and NW winds continue to
bring in colder air before we`ll rebound to end the weekend. Highs
on Saturday will likely be subfreezing for many, especially along
and north of the MA Pike, with highs in the low to mid 30s along the
immediate south coast. A nice break from the clouds is on tap as
well, given the drier air moving in through the entire column,
though winds will still be a bit breezy, moreso along the coast.
Saturday night with calm winds and clear skies we`ll see good
radiational cooling; lows dipping into the single digits in northern
and western MA and teens elsewhere.
Sunday we`re tracking a very weak mid level shortwave as well as a
sfc disturbance to our south that may work with some marginal
moisture (PWATs approaching 0.40") to bring light snow/rain showers
to the region. Odds are that the majority of locations will miss the
precip...best chance of showers being the orographically favored
western MA/CT. Clouds do increase through the day, though, as mid
and low level moisture increases. High temps rebound as flow turns
out of the south ahead of the next system...reaching low to upper
30s.
Sunday night and Monday...
A more organized (though still weak) system impacts southern New
England Sunday night and Monday as a trough and ~1010 mb surface low
move out of the Great Lakes into Canada. A warm front moves north
Sunday night bringing warm and moist flow into Monday which will
take temps back well above normal, in the mid to upper 40s Monday.
Rain and high elevation snow begin early Monday morning as a robust
LLJ moves in and precip lasts at least through the day on Monday
bringing up to a quarter inch or locally more.
Tuesday through Thursday...
This is where confidence drops appreciably as long range guidance
introduces very large discrepancies with the synoptic pattern,
especially toward mid week. The overall pattern continues to be very
zonal and progressive, which most likely keeps things unsettled with
quick hitters periodically through the week. Next chance comes as
soon as Tuesday, but timing these systems will be better done in the
coming days. Temperatures remain mild as the zonal flow precludes
any real intrusions of arctic air.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through tonight...High confidence overall, but lower confidence
in exact details.
Widespread IFR with areas of LIFR continue through tonight.
Patchy drizzle this evening with steady rainfall returning
after midnight. The rain may be locally heavy along the south
coast. The risk for pockets of freezing rain/drizzle will
continue tonight over the higher elevations.
Friday...Moderate confidence.
IFR/LIFR in the morning with areas of rain and fog, improving to
MVFR/VFR in the afternoon as winds shift to west. Rain with
pockets of freezing rain in the Berkshires may change to a
period of snow across western MA during the afternoon before
ending. The main issue for Friday afternoon will be very strong
west wind gusts developing behind departing strong low pres.
Wind gusts 40-50 kt will develop after 20z, especially south of
the Pike. Gusts may exceed 50 kt late Fri over Cape/Islands.
KBOS Terminal...High confidence overall. Lower confidence in
exact timing and details.
KBDL Terminal...High confidence overall. Lower confidence in
exact timing and details.
Outlook /Friday Night through Tuesday/...
Friday Night: Mainly VFR, with local MVFR possible. Strong
winds with gusts up to 50 kt.
Saturday through Saturday Night: VFR. Breezy.
Sunday: Mainly VFR, with areas MVFR possible. Slight chance SN.
Sunday Night: Mainly MVFR, with local IFR possible. Breezy.
Chance SN, chance RA.
Monday: Mainly MVFR, with local IFR possible. Breezy. Chance
RA.
Monday Night: Mainly MVFR, with areas VFR possible. Chance SN,
slight chance RA.
Tuesday: Mainly MVFR, with local IFR possible. Chance RA.
&&
.MARINE...
Short Term /through Friday/...High confidence.
Continued Storm Warnings for all south coastal waters with
gales elsewhere. Expecting a surge to 45-55 kt westerly wind
gusts Fri afternoon and early evening as the strong low pres
moves by. Seas building to 15-20 ft over southern waters.
Outlook /Friday Night through Tuesday/...
Friday Night: Moderate risk for gale force winds with gusts up
to 45 kt. Rough seas up to 18 ft.
Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 14 ft.
Saturday Night: Winds less than 25 kt. Areas of rough seas.
Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain.
Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas. Chance of rain.
Monday Night: Winds less than 25 kt. Areas of rough seas.
Chance of rain.
Tuesday: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain.
&&
.EQUIPMENT...
KBOX WSR-88D had a transmitter failure early Thursday morning.
It will remain offline until further notice. It is currently
expected to be fixed by Friday afternoon or evening.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory from 2 PM to 10 PM EST Friday for CTZ002>004.
MA...High Wind Warning from 2 PM to 10 PM EST Friday for MAZ022>024.
Wind Advisory from 2 PM to 10 PM EST Friday for MAZ005>007-
011>019.
High Wind Warning from 2 PM to 7 PM EST Friday for MAZ020-021.
Winter Weather Advisory until 7 AM EST Friday for MAZ002>004-
008-009-026.
RI...High Wind Warning from 2 PM to 10 PM EST Friday for RIZ008.
Wind Advisory from 2 PM to 10 PM EST Friday for RIZ001>005.
High Wind Warning from 2 PM to 7 PM EST Friday for RIZ006-007.
MARINE...Storm Warning from 1 PM to 10 PM EST Friday for ANZ232-254>256.
Storm Warning from 1 PM to 7 PM EST Friday for ANZ231-233>237.
Gale Warning from 1 PM to 11 PM EST Friday for ANZ230.
Gale Warning from 1 PM Friday to 4 AM EST Saturday for ANZ250-
251.
&&
$$
SYNOPSIS...KJC/BW
NEAR TERM...Belk/KJC/BW
SHORT TERM...KJC
LONG TERM...BW
AVIATION...Belk/KJC/BW
MARINE...KJC/BW
EQUIPMENT...Staff
Area Forecast Discussion
National Weather Service Goodland KS
548 PM MST Thu Feb 6 2020
.UPDATE...
Issued at 545 PM MST Thu Feb 6 2020
Simulated reflectivity forecasts via the most recent runs of the
HRRR suggest that light snow will largely be confined to eastern
Colorado (Kit Carson/Cheyenne counties) and will end later this
evening (by midnight). Given that snow is light/intermittent, for
example -- Burlington reported snow for only 10 minutes
(5:00-5:10 pm MST) with visibilities no lower than 2-3 miles --
and that temperatures are in the lower 30s, expect little in the
way of accumulation. A dusting to half inch will be possible in
western portions of Kit Carson and Cheyenne counties -- where
light snow will be relatively more persistent.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 219 PM MST Thu Feb 6 2020
Today, 500 mb RAP analysis and water vapor imagery showed a large
upper trough exiting the region to the east across the center of
the CONUS. As northwest flow increased over the western half of
the country, a series of weak shortwave troughs pushed through the
flow across the Rockies. As a result, some thick mid level clouds
developed and filtered into the area through the day. At 2 PM MT,
temperatures were in the upper 30s through mid 40s with northwest
winds at 10 to 20 mph (gusting to around 30 mph).
The main forecast concern during this short term period is the
potential for some light snow this evening through Friday for
locations west of the Colorado border.
Narrow bands of snowfall are expected to develop along the
Rockies and adjacent Plains in Colorado starting this evening and
continuing into Friday. The tri-state region is on the eastern
edge of the system making it very difficult to determine how far
east will be impacted. At this time, it appears that up to one
inch of snowfall is possible for the the western portions of our
Colorado counties. However, if the storm shifts its track, that
will change snow amounts so please stay tuned for updated
information.
Chances for light snow linger into Friday with strong northwest
flow continuing aloft. Any snow in the area should dissipate
Friday afternoon and evening, yielding dry conditions overnight.
Low temperatures tonight will be warmer than previous nights, as
our cold air mass continues to shift east, mixing keeps winds up
slightly, and cloud cover remains in place. Am expecting lows in
the upper teens to low 20s. Highs on Friday will be slightly
cooler behind a weak cold front, ranging in the mid 30s to low
40s. And finally, low temperatures on Friday night should be in
the mid teens to low 20s.
.LONG TERM...(Saturday through Thursday)
Issued at 317 PM MST Thu Feb 6 2020
Long range models show a ridge moving across the central Plains
through Saturday.A trough moves southeast from the Pacific
Northwest into the central Plains Saturday night. A low cuts off
over the western U.S. from the main trough by Sunday night. This
is when models start going their own way on the upper level
pattern.
Most models show the main trough continuing eastward as
the cutoff low shifts southward over the Baja of California. The
GFS is the outlier so while it could be correct, it is not as
likely. Continuing the split flow, a ridge follows behind the
trough into the central Plains Tuesday as the cutoff low remains
to the southwest.
Another trough digs south over the Intermountain West towards the
cutoff low. The cutoff low rejoins the main flow over the
southwestern U.S. Wednesday becoming a shortwave along the front
edge of the trough. The shortwave crosses the central Plains into
the Midwest Wednesday night into Thursday. The trough deepens over
the northern Plains Thursday with the Tri-State area remaining
under west-southwest upper level flow just ahead of the trough
axis.
A cold front moves south through the Tri-State area by Sunday.
High pressure then moves over the area through Tuesday. As a
surface low shifts southeast from northwest Canada into the
northern Plains by Wednesday, a surface low develops along the
Front Range of the Rockies in eastern Colorado. As both surface
lows move south and east across the central U.S. through Wednesday
night, a strong cold front is expected to trail behind the lows
and pass through the Tri-State area Wednesday. Once again, high
pressure begins pushing back into the central U.S. behind the
system of lows.
The first cold front this weekend will lower temperatures
slightly but be dry. The second cold front looks to be more
significant with a much more noticeable change in temperatures as
well as being accompanied by rain and snow. For Saturday through
Wednesday, highs will range from the mid-30s to lower 50s and lows
will drop into mid-teens to lower 30s. Wednesday night and
Thursday will be much colder with lows Wednesday night in the
teens and highs Thursday in the upper 20s to mid-30s.
There are some slight chance PoPs after midnight Monday night
until Tuesday afternoon but confidence is very low in any precip
at that time. The better chances for rain and snow will be Tuesday
night continuing through Thursday. There is still a lot of
uncertainty in how the upper level pattern will progress next week
therefore reflecting the same uncertainty on the precipitation
chances.
It looks like a breezy extended forecast period with a hectic
surface pattern. Much of the extended forecast period could see
gusts up to 35 mph particularly when associated with passing cold
fronts.
This next week upper level pattern will need to be monitored
closely particularly for snow and wind potential.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 342 PM MST Thu Feb 6 2020
Increased cloud cover is expected this evening and overnight as
light snow develops in eastern Colorado. Biggest concern during
this TAF period will be how low ceilings get as well as how far
east snowfall pushes into the region. At this time, low end VFR
conditions are forecast for this evening. However, it is possible
that ceilings could dip into the MVFR category. Additionally, it
appears that any precipitation should remain west of KGLD, but
this will need to be monitored. Northwest winds are forecast
through the period, generally around 10 knots.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...VINCENT
SHORT TERM...JBH
LONG TERM...NEWMAN
AVIATION...JBH
Area Forecast Discussion
National Weather Service Wichita KS
600 PM CST Thu Feb 6 2020
.SYNOPSIS...
Issued at 323 PM CST Thu Feb 6 2020
Near normal temperatures will continue through Friday, followed by
above normal temperatures and breezy conditions on Saturday. Late in
the weekend, a cold front will cross the region, sending
temperatures back down closer to, or below, normal. The chance of
precipitation looks very low through Saturday. On Sunday, a band of
showers may develop across southeast Kansas ahead of the advancing
cold front. Behind that front, precipitation may tend to be focused
south of Kansas, but at least a low chance may develop by mid-
week.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 323 PM CST Thu Feb 6 2020
Early this afternoon, a weak area of low pressure was centered over
eastern SD, with a cold front trailing back to the W/NW into the NRN
Rockies. South of the low, a light, westerly downslope flow has
allowed temps to reach the low to mid 40s across central Kansas.
Lingering snowcover and less of a downslope component to the wind is
keeping eastern Kansas cooler (only in the mid to upper 30s).
The SFC low will gradually shift E/SE through Friday, allowing a
weak cold front to push SE across central/eastern KS. We`re not
expecting a significant airmass change behind the front, with
thickness values very similar to what we are seeing today. 850mb
temps will be colder than today, but the NW component of the SFC-low
level flow may offset the cooler temps aloft somewhat.
Weak high pressure then settles in Friday night. Mid-level clouds
may attempt to stream into the area during that time, preventing a
more ideal radiational cooling setup. However, I did go ahead an
nudge lows down some, especially SE KS where winds will likely
remain lighter the longest.
Return flow very quickly ramps up on Saturday within a transient,
zonal flow regime. While the SFC winds may tend to back a bit as
cyclogenesis occurs over the Central High Plains, the westerly low-
level flow combined with increasing southerly SFC flow should
support above normal temperatures Saturday afternoon. The more
backed/southerly component of the SFC winds may lend itself to a
less-than-perfect downslope setup, but confidence is still high
regarding warmer temps. For those reasons, I went above blended
guidance for highs Saturday. Warmer SFC temps (assuming that
verifies) should also support steeper low-level lapse rates and
better mixing, leading to stronger winds than blended guidance
suggests.
Martin
.LONG TERM...(Sunday through Thursday)
Issued at 323 PM CST Thu Feb 6 2020
The focus during this period continues to be the evolution of a
broad, amplified, and positively-tilted upper level trough
developing over the WRN US. Within that trough, embedded shortwaves
will also be an important consideration. Initially, the SFC low
developing over the High Plains on Saturday will translate east,
allowing a cold front to push across the Central Plains Sunday
afternoon/evening. Ahead of this front, we may briefly be able to
tap into some Gulf moisture returning north ahead of the developing
upper level trough. As the previous shift mentioned, the best chance
of this still appears to be focused over SE KS where PWats may
approach 1" briefly. It is in that area where a narrow band of
showers should be able to develop ahead of the front.
In the wake of that front, a more broad area of SFC high pressure
will spread south across the Plains, and more or less remain in
place through mid-week. From mid-week on, model guidance
(deterministic and ensemble) begins to show more variation. The main
culprit appears to be what happens with a deeper, closed low that is
forecast to dig south along the US West Coast early next week. The
trend has been deeper and further south with the low as it digs into
the SW US, potentially reaching as far south as NRN Mexico. This
trend would likely favor a drier solution, with precip being focused
south of Kansas. That said, we don`t want to jump too quick on a
completely dry solution as there remains some uncertainty in how
that WRN US closed low evolves. Should it not dig as far south, the
precip potential could end up higher in our neck of the woods. Even
with the further south solution, there could still be some precip
potential with other waves embedded within the trough. We`ll
continue with some low pops next week, but keep in mind the latest
trend has been towards less precip potential. Temperatures also fall
in the less-certain camp due to differences with the timing and
amplitude of various embedded waves. In general, it appears each
wave may have a brief warmup followed by a quick surge of colder
air. The net effect is probably near average temps.
Martin
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 600 PM CST Thu Feb 6 2020
At issuance, a weak pre-cold frontal sfc trof was entering Eastern
Nebraska, Central & South-Central KS while the cold front extended
from Central Nebraska, thru NW KS to extreme SE CO. Winds across C
& most of SC KS have shifted to the NW but speeds were only ~10kts
with no gusts. The trof & front will continue their E/SE treks
across the rest of KS tonight with Altocu from 10,000-13,000ft
dropping to ~50,000ft (Stratocu) late this eve & overnight. Cigs
may become a problem across C KS 09-12Z as short-term soundings,
more specifically the HRRR & RAP, depict a potential for IFR &
perhaps even LIFR cigs spreading into the KRSL, KGBD & KSLN
terminals during this period. This period will be monitored
closely as evening progresses.
&&
.FIRE WEATHER...
Issued at 323 PM CST Thu Feb 6 2020
Overall, fire weather concerns should remain on the lower side
through the weekend. However, it is worth noting there will be a
period of breezy conditions on Saturday, which may slightly
elevate fire concerns during the afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 26 45 25 53 / 0 0 0 0
Hutchinson 27 44 23 52 / 0 0 0 0
Newton 26 42 24 51 / 0 0 0 0
ElDorado 25 43 24 51 / 0 0 0 0
Winfield-KWLD 25 47 26 53 / 0 0 0 0
Russell 25 43 21 51 / 10 0 0 0
Great Bend 26 44 22 53 / 10 0 0 0
Salina 26 42 22 52 / 10 10 0 0
McPherson 26 42 22 51 / 0 10 0 0
Coffeyville 22 46 24 51 / 0 0 0 0
Chanute 23 44 23 48 / 0 0 0 0
Iola 23 43 23 48 / 0 0 0 0
Parsons-KPPF 22 45 23 49 / 0 0 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...RM
SHORT TERM...RM
LONG TERM...RM
AVIATION...EPS
FIRE WEATHER...RM
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
907 PM EST Thu Feb 6 2020
.UPDATE...
Issued at 905 PM EST THU FEB 6 2020
The last few HRRR runs and RAP runs continue to predict a band of
heavier QPF between 6Z and 12Z a few miles either side of a line
from near the I 75 corridor northeast to near Hazard and Jackson
and then into Martin and Johnson Counties. With this agreement and
a slightly quicker changeover it appears that snowfall could
reach the 2 to 3 inch range, especially on the ridgetops from near
Williamsburg and London northeast to near Jackson, West Liberty,
and Paintsville. QPF, snowfall, T, and min T were updated
accordingly for the overnight hours. This scenario will continue
to be monitored for any needed further adjustments.
UPDATE Issued at 730 PM EST THU FEB 6 2020
Drizzle or light rain is occurring across the region at this time
as a shortwave trough approaches from the southwest. Precipitation
should increase in coverage and probably intensity as well as
midnight approaches. Temperatures aloft will also begin to cool
and additional cooling is expected overnight which should lead to
rain changing to snow. Warm and wet ground will limit any
accumulations at least initially with elevated and grassy
surfaces and ridgetops being most favored for accumulations.
Some minor adjustments were made at this point based on hourly
observations to temperatures and dewpoints. Trends for the wintry
weather threat and HRRR trends for later tonight will continue to
be monitored for any adjustments to qpf and snowfall. High water
and some flooding will continue overnight on portions of the KY,
Cumberland, and Big Sandy basins.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 451 PM EST THU FEB 6 2020
An area of low pressure is progressing east this afternoon based
on the afternoon surface analysis. An upper level trough axis is
set up across the ARKLATEX region. We remain more or less in a dry
slot ahead of the previously mentioned upper level trough axis.
This feature will eject northeastward tonight and become
negatively tilted. This along with frontogenetical forcing at
around 700mb will lead to a swath of precipitation across eastern
Kentucky. This moisture will arrive as west and northwest winds
advect cold air into the region through the night. This will allow
this to change from rain to snow through the night as this colder
air arrives. There are some caveats to this...first one is it has
been relatively warm heading into the event that would lessen any
initial accumulations, and the second is where the higher
precipitation amounts setup is in question. This is mainly
agreement among the models on where the deformation zone sets up.
However, despite the caveats we issued a Winter Weather Advisory
for all of eastern Kentucky given this will be falling during
commute time and could at least affect elevated road surfaces.
This west to northwest flow on Friday will give portions of the
Ohio Valley some weak connection to lake Michigan into the day
tomorrow especially in the far southeast. This will keep chances
of rain and snow and eventually flurries as we move through the
day. Eventually moisture will dry up some as weak nosing of high
pressure progresses north. The next wave will arrive after this
period so keep it mostly dry on Friday night.
.LONG TERM...(Saturday through Thursday)
Issued at 505 PM EST THU FEB 6 2020
The long-term period starts 12Z Saturday with a broad low-
amplitude 500 mb trough across much of the CONUS with its mean
axis near the Mississippi River Valley. Meanwhile, a persistent
subtropical ridge will be parked across eastern Pacific. Closer to
the CWA, a robust shortwave trough and vort max, embedded in the
fast cyclonic flow rounding the base of the trough, will be
crossing the Lower Ohio Valley.
The trough axis and attendant vort max pass across eastern
Kentucky during the day Saturday, then dampen and exit to the east
Saturday night. At the same time, a positively tilted trough will
dig across the Pacific Northwest, resulting in a fast, zonal flow
across much of the US for Sunday. Multiple shortwaves will
continue to carve out the deep upper-level trough across the
Western CONUS Monday through Thursday, while a compensating
subtropical ridge builds northward from the Caribbean into Western
Atlantic.
At the surface, Saturdays shortwave trough will be accompanied
by a weak surface low traversing the Ohio Valley. This will bring
renewed chances of light precipitation, starting off as snow
during the morning hours, changing to mainly rain in the valleys
by afternoon; but, likely remaining more of a mix over the higher
elevations. Some models are hinting at some weak instability late
afternoon and early evening with a pseudo-cold frontal passage,
which could result in briefly heavier precipitation rates. At this
time, confidence in this materializing is low, so little to no
accumulation is expected. This weak system quickly exits Saturday
evening as the zonal flow takes over aloft.
Surface high pressure builds across the Southern Appalachians
Sunday morning, bringing dry conditions and sunshine, which should
boost afternoon temperatures into the upper 40s to mid 50s. While
we enjoy a brief respite from the gray skies, a weak clipper low
will race from the High Plains of Montana early Sunday to the St.
Lawrence Valley by 12Z Monday.
The next chance of precipitation arrives Monday as this system
drags a trailing cold front across eastern Kentucky. The front
becomes nearly stationary to our south and east Monday night
through Tuesday night while multiple disturbances ride along the
front. Models diverge as to where the front stalls, which will
have significant bearing on the sensible weather in Eastern
Kentucky during this time frame.
At this point, the GFS keeps the front farther to the south
keeping our area colder, with most precipitation, aside from a
little snow early Wednesday, falling to our southeast. Meanwhile,
the Euro brings periods of heavier rainfall into eastern Kentucky
ending as a little snow Wednesday morning. The Euro, then brings
in surface high pressure for Wednesday with modest height rises
while the GFS keeps the area under a more cyclonic pattern. Ahead
of the cold front on Monday, temperatures will warm well into the
50s. Thereafter, temperatures will strongly depend on the location
of the front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 730 PM EST THU FEB 6 2020
Mostly IFR with some spotty MVFR was observed at issuance time.
CIGs will generally remain in the IFR range through 12Z as low
stratus persists as a shortwave trough approaches. This should
lead to an increase in coverage of precipitation with a change
over to snow from around 4Z to 12Z. This snow or a rain and snow
mix should lead to IFR or lower vis at times as well. Improvements
into the MVFR range are generally expected 11Z to 18Z as the
shortwave departs. Overall the winds will remain northwest and
west near 10 KT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 1 PM EST Friday for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JP
SHORT TERM...DJ
LONG TERM...GEERTSON
AVIATION...JP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
610 PM CST Thu Feb 6 2020
.SHORT TERM...
207 PM CST
Through Friday night...
Lingering deformation with transient f-gen bands continues to
peel slowly off to the east and lingers mainly over northwest IN
early this afternoon. This synoptic system snow will end late this
afternoon and likely an inch or less of additional snow before
ending.
Attention will then turn toward lake effect snow (LES) potential.
Have already seeing some lake effect/lake enhanced snows into
northeast IL. Will probably see some waning in the intensity of
the snow this afternoon as depth of saturation decreases with
departing synoptic forcing and otherwise marginal lake effect
parameters. Forecast soundings this evening suggest inversion
heights will rise with the approach of the upper trough. Air mass
is not particularly cold, so instability isn`t terribly
impressive. However, ambient low level lapse rates are progged to
already be pretty steep which when combined with some modest lake
induced instability and a developing land breeze convergence axis,
the set-up looks modestly decent for LES.
LES can be very difficult to predict, particularly in these
somewhat borderline cases. Most likely scenario looks to be light
to occasionally moderate lake effect snow showers, potentially
with some fairly deep inland penetration given the steep low level
lapse rates. Residence time of the beefier LES and will probably
be short enough to keeps mainly less than 2" most areas. Have seen
LES over perform in otherwise marginal looking set-ups before, so
wouldn`t completely rule out higher totals, but not seeing
anything that would lead me to believe that will be the case this
go around. LES should shift into northwest IN late tonight/early
Friday, then east out of Porter County Friday afternoon.
- Izzi
&&
.LONG TERM...
226 PM CST
Friday Night through Thursday...
An unsettled pattern with frequent disturbances and associated
precipitation chances will be the rule for the next week. In
summary of forecast expectations, first light snow is likely for
at least a portion of the area Friday evening into the night with
minor accumulation of one inch or less expected. On Sunday, the
likelihood of precipitation has increased and mainly looks to be
snow north. Depending on the specific track of this system, which
is still of lower confidence, some of that snow could be moderate
in intensity. A couple inches north are certainly in the realm of
possibilities with this. Temperatures have fluctuations but
nothing major either way through Tuesday, typical of a progressive
pattern and mainly low amplitude features.
A low amplitude short wave across the Dakotas this afternoon will
gradually work its way southeast in the next 36 hours, rounding a
broader long wave trough over central/eastern Canada and United
States. This looks to hold its own at least through Friday evening
before de-amplifying/weakening. While upper forcing is limited with
this detached wave from the stronger upper flow, the lift and
saturation are collocated with the dendritic-growth zone in
forecast guidance. Commonly in these situations, it does not take
much to rattle out light snow. So have increased PoPs for this low
QPF event, and this increase was especially in the western and
southern forecast area. Flurries may linger into Saturday.
The next system arrives on Sunday with stronger jet support but
is more progressive. This is a Pacific/Clipper hybrid system and
brings precipitable waters up to one half inch with it. The warm
sector of this system is quickly impinging into the area on
Sunday, but depending how early precipitation starts (especially
in the northern CWA) it may prevent a changeover to rain and a wet
snow would be more favored. This system has an orientation and
path that would favor a swath of decent accumulating snow
immediately north of the surface low given the forecast parameters
presently in the GFS and ECMWF, but right now on both of these
this is projected across central/southern Wisconsin. The Canadian
model is more focused over the area though and that will be
something to watch. For now have raised PoPs consistent with
guidance and their ensembles, and do have some minor accum noted
in the northern half of the CWA.
The northwest flow continues for the first part of next week. The
split flow pattern has waves forecast midweek that have shown
phasing in the EC guidance but a more mixed signal in others.
Conceptually there are several ingredients in place for a
broader-reaching synoptic system and one with a lot of moisture
and baroclinicity to work with in the middle of the country. A
great deal of uncertainty but a fair signal for six or so days
out.
MTF
&&
.AVIATION...
For the 00Z TAFs...
Aviation forecast concerns:
-Lake effect snow showers impacting ORD/MDW/GYY this tonight
(into Friday for GYY). Brief IFR visibilities in heavier snow
showers.
Low pressure continues to track northeast across the upper Ohio
Valley and Appalachians early this evening, pulling away from the
local area. Light snow on the trailing edge of this system is
transitioning to lake effect snow showers, due to northeasterly
low level flow off the lake and colder air aloft. The main low-
level convergent axis was focused along the west shore of the lake
as of late afternoon, from off MKE into the Chicago terminals.
High-res model guidance is not doing a particularly good job of
indicating the westward extent of this activity at this time,
though the general trends in guidance would support a gradual
southward shift of the band through the evening hours. RAP model
forecasts of the low-level convergence fields indicate the focus
would setup mainly just east/southeast of ORD (into MDW) by mid-
evening. Surface observations beneath the stronger radar returns
have generally indicated IFR visibilities (around 1 1/2SM) and
MVFR ceilings. Given the bands expected southward movement, ORD
would likely have the shortest period of potential impact early
this evening, with the threat lingering longer at MDW, and
persisting into Friday morning at GYY.
Outside of the lake effect snow bands and associated MVFR clouds,
quiet VFR conditions are expected. Winds will shift from north or
north-northeast this evening, to northwest and eventually west
during the day Friday as the low pressure system to our east
continues to move away, and weak high pressure moves in. A
clipper-like system will approach the area later Friday and Friday
night, with development of a gradually lowering VFR cloud layer
during the day. The greatest potential for precipitation with this
approaching system looks to go mainly south of the terminals
Friday night, though there is the potential for some low-impact
light snow across the terminals. Have indicated a PROB30 at ORD
and MDW later in the evening for that potential.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IL nearshore waters until noon Friday.
Small Craft Advisory...IN nearshore waters until 3 PM Friday.
&&
$$
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Area Forecast Discussion
National Weather Service Newport/Morehead City NC
843 PM EST Thu Feb 6 2020
.SYNOPSIS...
A strong cold front will cross through tonight and move offshore by
Friday morning. High pressure will have a brief stint Friday before a
weak shortwave passes through late Saturday. High pressure will
rebuild into the area for early next week before more unsettled
weather possible by Tuesday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 815 PM Thu...Tornado Watch remains in effect for all of
MHX CWA through 1 AM. Latest radar imagery shows strong bowing
storms lifting ENE through Eastern NC. Instability has lessened
with loss of diurnal heating with MUCAPE around 500 J/Kg ahead
of this line however shear remains very strong around 60-70 kt.
Will continue to watch this convection for tornado and damaging
wind threat through early this evening as it moves into a more
favorable environment. Generally seeing stratiform rain behind
the heavier line, but HRRR shows another enhanced line as the
LLJ increases to aoa 70 kt ahead of approaching cold front as
the sfc low deepens as it moves newrd through the interior
Carolinas. Have seen 1-2" of rainfall and locally up to 3" where
cells have been training this evening. Still think any flash
flooding would be localized, and be mainly associated with the
main QLCS moving through. Gusty gradient winds will continue,
peaking tonight along the coast, with gusts reaching 45 to 50
mph for the coastal areas, namely downeast Carteret through the
OBX, where Wind Advisory continues.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
As of 250 PM Thu...Cold front will push offshore Friday
morning, and bulk of precip assoc with front should be offshore
by daybreak with just low chc of lingering shra mainly cst and
north through late morning. Main story Fri will be gusty winds
due to tight pres grdnt and deep mixing. Expect WSW winds to
gust 40 to 45 mph inland and 45 to 55 mph coast. Issued Wind
Advisory for all counties beginning Fri morning. High temps will
be mild still, mostly in the low 60s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
As of 230 AM Thu...Quiet weather expected thru early next week.
Unsettled weather will develop Tue as another front impacts the
region.
Saturday through Monday...Cooler and drier high pressure
returns for Sat with highs around 50. Temps then begin to
moderate Sun as SW winds return with highs around 60. Very warm
again by Monday with some inland sites reaching 70...60s for
the coast. This period will be mainly dry with just slight chc of
a shra Sat night as weak short wave passes to the N.
Tuesday and Wed...Rain chc increase Tue as next cold front
approaches and crosses Tue night...for now will keep pops in
chc range given uncertainty on timing. Looks like front will
push thru Wed with just very slight chc of shra. Cont mild with
highs Tue ahead of the front 65 to 70 inland...highs Wed in the
60s.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Short Term /through Friday/...
As of 730 PM Thu...Line of strong storms moving across rtes
this evening with stratiform precip continuing behind the line.
Sub-VFR conditions expected much of the overnight, generally
MVFR, but dropping to LIFR in heavier showers. A period of
LLWS is likely tonight as well. The widespread precipitation is
forecast to end by 10Z Fri with VFR conditions following through
Fri. Gusty SSW winds with gusts to 40 kt will occur through
early Fri afternoon.
Long Term /Fri night through Tuesday/...
As of 100 PM Thu...VFR conditions are expected through Tue with
only slight chc of a shra Sat night, otherwise dry.
&&
.MARINE...
Short Term /through Friday/...
As of 830 PM Thu...Dangerous marine conditions will continue
across the waters through Friday. Latest obs show SSW winds
20-30 kt gusting to 35-45 kt across the outer waters with seas
4-6 ft north of Oregon Inlet and 7-12 ft south. Strong winds
will continue through Friday along with dangerous seas. Gale
Warnings continue for the waters with SSW winds 25-35 kt gusting
40-45 kt tonight, becoming more W/WSW Friday. Seas will build
to 10-20 ft, highest across the outer waters. Winds may briefly
diminish early Friday morning, but increase again dramatically
again Friday behind the front. Low water expected across the
Neuse, Pamlico, Pungo Rivers tonight into Friday.
Long Term /Fri night through Tuesday/...
As of 230 AM Wed...Winds become NW and diminish to 10 to 20 kts
later Fri night. On Sat winds become light as high pres builds
across. Seas will subside to 6 to 9 feet late Fri night and drop
to 3 to 5 ft later Sat. Light winds cont Sun with seas dropping
to 2 to 3 ft. SW winds return Mon as high pres moves offshore
with speeds increasing to 10 to 20 kts late and seas building to
3 to 5 ft.
&&
.HYDROLOGY...
As of 3 PM Thu...The combination of already high river levels,
and heavy rains across most of the state, will lead to the
possibility of minor river flooding on the main stem rivers
(Tar, Neuse, NE Cape Fear basins) by this weekend.
&&
.TIDES/COASTAL FLOODING...
As of 3 PM Thu...Coastal Flood Advisory conts for soundside
Outer Banks with minor inundation 1-2 ft agl. Strong southwest
winds will peak tonight. This may bring minor coastal flooding
across soundside locations of the northern Outer Banks and
Hatteras Island. Then gusty west to southwest winds will
continue through Friday night keeping water levels elevated
along soundside Hatteras Island. High Surf Advisory conts for
oceanside areas south of Rodanthe, with potential for minor
beach erosion and localized ocean overwash. Low water levels are
likely to occur on the Neuse River starting tonight and a Low
Water Advisory has been issued as water levels up to 2 ft below
normal expected thru Fri evening. Low water advisory continues
into Fri evening for Neuse, Tar, Pamlico and Pungo Rivers.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...High Surf Advisory until 1 AM EST Saturday for NCZ195-196-199-
204-205.
Wind Advisory from 8 AM to 7 PM EST Friday for NCZ029-044>047-
079>081-090>092-094-193>195-198-199.
Wind Advisory until 7 PM EST Friday for NCZ196-203>205.
Coastal Flood Advisory until 1 AM EST Saturday for NCZ203-205.
MARINE...Low Water Advisory from 10 AM Friday to 1 AM EST Saturday for
AMZ136.
Gale Warning until 5 PM EST Friday for AMZ136-137.
Low Water Advisory until 1 AM EST Saturday for AMZ137.
Gale Warning until 7 PM EST Friday for AMZ131-135-150-230-231.
Gale Warning until 11 PM EST Friday for AMZ152-154-156-158.
&&
$$
SYNOPSIS...MHX
NEAR TERM...CQD/SK
SHORT TERM...CQD
LONG TERM...RF
AVIATION...JME/SK/TL
MARINE...RF/CQD/SK
HYDROLOGY...MHX
TIDES/COASTAL FLOODING...MHX
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Morristown TN
904 PM EST Thu Feb 6 2020
.DISCUSSION...
Updated to extend Winter Weather Advisory into the northern
Plateau and Lee County Virginia. Also, up winds for Friday to near
wind advisory levels.
Satellite shows another short-wave rotating across the lower
Mississippi valley into the Gulf coast states. A 135-140kt 300mb
jet associated with the trough will rotate across the Gulf coast
states toward the southern Appalachians overnight placing the area
under the favored left exit region of the jet. Mosiac radar
already shows an increasing coverage and intensity of
precipitation developing.
Decent dynamics will occur between 04-13Z time-frame spreading
widespread precipitation across the region. Enough dynamic cooling
and closer proxmity to colder airmass west and northwest of area
will allow the northern Plateau to change quickly over the snow.
This is being advertised by the SPC HRRR Browser. Expect several
hour period of light to moderate snow there between 06-12Z with
accumulations of 1 to 3 inches possible over mainly grassy and
elevated surfaces. However, secondary roadways and higher
elevations of intersate 75 on Jellico mountain may experience
travel concerns.
As dynamics lifts northeast Friday morning cold air aloft will
steepen the lapse rates with models showing 40-80 J/Kg of CAPE.
This will be enough to keep scattered showers in the forecast.
Also, orogaphic lift will increase as surface low lifts northeast
and high pressure builds into the region tightening the pressure
gradients. Windy conditions will develop Friday with westerly
winds of 15 to 30 mph.
Made some minor changes to hourly temperature forecast especially
across the northern Plateau.
&&
.AVIATION...
00Z TAF DISCUSSION.
Another system will move across the area overnight through Friday
morning producing another round of precipitation, mainly rain but
may mix with snow or sleet at TRI (possibly TYS) tomorrow. Flight
conditions will remain MVFR/IFR through most of the forecast but a
period of LIFR due to ceilings expected between 06-14Z.
Winds will increase to the west Friday morning as the associated
surface trough moves through the region tightening the pressure
gradients. Gusts over 25kts are possible.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 35 42 32 50 31 / 60 30 20 20 10
Knoxville McGhee Tyson Airport, TN 35 39 31 46 29 / 100 50 10 40 20
Oak Ridge, TN 34 39 30 46 28 / 90 50 10 40 10
Tri Cities Airport, TN 34 38 27 42 28 / 100 70 30 40 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Winter Weather Advisory from 1 AM to 4 PM EST Friday for Blount
Smoky Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
Mountains-Southeast Carter-Southeast Greene-Southeast
Monroe-Unicoi.
Winter Weather Advisory from 1 AM EST /midnight CST/ to 1 PM EST
/noon CST/ Friday for Bledsoe-Campbell-Claiborne-Morgan-
Scott.
VA...Winter Weather Advisory from 1 AM to 4 PM EST Friday for Russell-
Wise.
Winter Weather Advisory from 1 AM to 1 PM EST Friday for Lee.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
641 PM MST Thu Feb 6 2020
.UPDATE...
Issued at 638 PM MST Thu Feb 6 2020
upper dynamics and a little low level upslope, have caused a band
of heavier snow to develop over western El Paso County. Forecast
models have a poor handle on this situation and it is difficult to
know how long this band of snow may remain over the area. Have
added a winter weather advisory for southern El Paso County (there
is already one out for northern El Paso County), for the snow and
the potential for icy/snowpacked roads in El Paso County.
&&
.SHORT TERM...(This evening through Friday)
Issued at 334 PM MST Thu Feb 6 2020
Main forecast concerns are with heavy snow and strong winds across
the central mountains continuing tonight into Friday, as well as the
higher likelihood of light to moderate with occasional bursts of
heavy snow across the lower elevations, especially along and just
east of the I-25 corridor.
Have seen snow really blossom across the central mountains over the
last several hours, as stronger mid/upper level northwest flow with
embedded shortwave energy has moved overhead. This will not only
continue but also likely further intensify tonight, as even stronger
flow and impulses of energy moves overhead. Latest RAP analysis
indicating steepening lapse rates across the region with short term
guidance showing this trend continue into tonight, which will
further support increasing snow intensity. With high snowfall rates
and with increasing gusts up to 65 mph tonight, current winter storm
warning is on track for the Mosquito and Sawatch Mountains as well
as Lake county. No real change expected for these areas going into
Friday as the pattern will remain the same, and support additional
heavy snow with strong wind gusts. Snow should begin to see a
diminishing trend late in the day on Friday as this system begins to
slowly pull away. However, do think snow will likely continue across
the central mountains into Friday night.
Concerns for snow across the lower elevation remains at this time,
especially for northern El Paso county where a Winter Weather
Advisory had been issued tonight into Friday. Latest radar imagery
depicting some light returns across the plains this afternoon, but
with little to no snow likely falling at his time. Flow and forcing
are increasing this afternoon, however, some drier air in the lower
levels will need to be eroded first. The previously mentioned
strengthening mid/upper level flow with embedded energy will help
support additional snow development this evening into later tonight
and Friday for parts of the plains. As flow aloft further increases
this evening and as additional upstream energy moves overhead, will
see already noted lee troughing across the eastern half of Colorado
dive south across the state. This trough axis is anticipated to push
across the Palmer Divide this evening, with this low level
convergence and then northerly flow assisting in snow development
this evening into the overnight hours. The support/forcing along
with the previously noted mid level lapse rates and now steep low
level lapse rates, will support light to moderate snow, with
occasional brief bursts of heavy snow. Highest confidence for this
occurrence is across the northern half of El Paso county, where the
current Advisory is in effect. Have not made any changes to the
forecast snowfall, with 2 to 5 inches still expected across this
location. Also, no changes to this start time with snow beginning by
early to mid evening. Those traveling in this location can expect
rapidly deteriorating conditions through mid evening, with the brief
bursts of heavier snow supporting high hourly snowfall rates
possibly up to 1-2 inches at times. This will significantly reduce
visibility and quickly create snow covered roads, with hazardous
driving conditions likely this evening. Snow will likely continue
across this location on Friday and have maintained higher pops
during the day. Somewhat lower confidence with additional snowfall
on Friday, however, do think the hazardous conditions will remain
and impact the Friday morning commute.
Have been closely monitoring additional snow expected for areas
along and just east of the I-25 corridor tonight. Guidance
indicating the southward moving trough axis will support snow over
additional parts of southeast Colorado. However, guidance also
continues to vary greatly as to the placement of this snow as well
as the amount of snowfall. Even at this time, short term guidance
and even 18z guidance coming in at this time is varying. This has
been frustrating as guidance has been hinting that the moderate to
heavy snow which will be observed to the north could extend
southward. Additional forcing owing to strengthening FGEN has been
something worth watching, as well as the possibility for both
upright and slantwise instability. This would support more banded
snowfall, with moderate to occasionally heavy snow. However, once
again guidance has not been consistent with this idea or placement
of any bands of snow tonight. It`s possible that bands of snow could
setup along a line from Colorado Springs to Pueblo, or to the east
maybe more towards the La Junta area. With this lower confidence,
have not issued any additional Advisories this afternoon, but did
try to raise pops and snowfall amounts as well as issued a Special
Weather Statement to highlight this possible snow and impacts. If
this band sets up, wherever it does I do think that a quick 1-2
inches or possibly more under heavier snow will be possible. This
would support reduced vis, snow covered roads and hazardous driving
conditions. Please continue to monitor the forecast for any updates
this evening, and those traveling along and just east of I-25 from
Colorado Springs southward should be prepared for possible hazardous
driving conditions.
.LONG TERM...(Friday night through Thursday)
Issued at 334 PM MST Thu Feb 6 2020
Friday night-Saturday...Strong north to northwest flow aloft across
the region is progged to moderate Friday night and then become more
westerly through the day Saturday, as an embedded jet streak,
translating east across the Rockies, continues out into the Upper
Midwest and High Plains, as more eastern Pacific energy, moving
onshore across the Pacific Northwest Friday night, digs across the
Intermountain West. With that said, will continue to see orographic
snowfall across the central mountains Friday evening, with snow
tapering off into early Saturday morning. Looking at an additional 1
to 4 inches across the central mountains through Saturday morning,
greatest accumulations north of Cottonwood Pass. Further east, best
potential for banded snow remains generally north and east of
southeast Colorado, though kept scattered pops intact across the
Palmer Dvd through the evening, with all pops tapering off through
the overnight hours. Pops slowly increase again into Saturday after
noon across the central mountains, with moisture increasing once
again within the westerly flow aloft. Near seasonal lows expected
across the region overnight Friday, with the developing westerly
flow expected to help boost temperatures into the mid 40s to mid 50s
across the lower elevations on Saturday, with highs mainly in the
30s and 40s across the higher terrain.
Saturday night-Monday night...Latest model runs and ensemble data
are in fairly good agreement of a split flow pattern developing
across the region, as a portion of the Intermountain West system
continues across the Northern Tier and Upper Midwest through the day
Monday, while secondary energy digs across the southern Great Basin
and into the Desert Southwest by Monday night. This pattern supports
good chances of precipitation for areas over and near the higher
terrain, especially along the ContDvd where more winter weather
highlights may be needed in the near future. Pattern also supports
below seasonal temperatures, especially across the Plains behind a
passing cold front late Saturday night and early Sunday morning.
Tuesday-Thursday...Lower confidence forecast remains in the offing
as more, hard to time energy, digs across the Rockies within a
continued northwest flow pattern. Models are also struggling on
where or if the southern stream energy across the Desert Southwest
merges with more northern stream energy digging across the Rockies.
With that said, stayed with the blended model solution, which starts
to ramp up pops again from west to east Wednesday and Thursday,
along with temperatures at to slightly below seasonal levels.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 334 PM MST Thu Feb 6 2020
No real big changes to the TAFs at this time, with the main
concerns/challenges still snow and low ceilings later this evening
through Friday morning mainly for COS and PUB. Latest radar imagery
is showing some returns, however, snow is not likely occurring at
this time. Still expect snow to develop by early to mid evening for
both locations, with COS likely starting slightly sooner than PUB. A
period of light snow, possibly moderate to briefly heavy, is then
expected for a time during the overnight hours. Have maintained
similar vis and not really trended the TAFs toward the heavier snow
with this forecast as confidence is still low on this occurrence.
Will continue to monitor trends though, and update as needed. Under
this snow, VFR ceilings will fall to MVFR, possibly low end MVFR,
tonight. These lower ceilings will likely remain Friday morning as
well as some snow, but do expect an upward trend through midday
along with diminishing snow.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until midnight MST Friday night for COZ058-
060.
Winter Weather Advisory until 8 PM MST Friday for COZ084.
Winter Weather Advisory until 3 AM MST Friday for COZ085.
Winter Storm Warning until 5 PM MST Friday for COZ059.
&&
$$
UPDATE...28
SHORT TERM...RODRIGUEZ
LONG TERM...MW
AVIATION...RODRIGUEZ