Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/30/17
Area Forecast Discussion
National Weather Service Albany NY
748 PM EDT Sun Oct 29 2017
.SYNOPSIS...
A powerful coastal low pressure system will rapidly
intensify as it tracks northward into upstate New York late tonight
and moves into southern Quebec tomorrow. The cyclone will tap into
tropical moisture, with the rain becoming heavy at times tonight.
Strong winds capable of damage will develop over eastern New York
and western New England tonight into tomorrow. The winds will
subside Monday night into Tuesday, as some lake effect rain and snow
showers will impact the western Adirondacks with seasonably cool and
dry weather for the rest of the region.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 720 EDT...
A High Wind Warning will be is in effect until 6 PM Monday from
the Hudson Valley eastward including all of western New
England...
A High Wind Warning will be in effect from Midnight Tonight
until 6 PM EDT for the western Adirondacks, western and central
Mohawk Valley, Schoharie Valley, Helderbergs, and the eastern
Catskills...
Flash Flood Watch remains in effect across the entire region
until noon Monday...
A significant multi-hazard event is ongoing as a deepening and
intensifying low pressure system impacts the region with heavy
rain, the potential for flooding/flash flooding and
strong/damaging winds.
Low pressure has now deepened to about 988 hPa just
east/northeast of the Delmarva Region, as an impressive
rainshield with embedded heavy rain elements continue to impact
the forecast area, except for some shadowing/downsloping that
may be going on west of the southern Greens Mtns. A pronounced
heavy rain band is lifting north of Long Island toward NW
CT/mid-Hudson Valley. This is associated with the strong upward
vertical motion and 2-d FGEN in the deformation region ahead of
the wave. The winds have not materialized yet, but the
GFS/NAM/ECMWF and several HIRES CAMS, such as the 3-km HRRR and
3-km NAM show a dry slot punching into the region as the deep
and intense low races north/northwest west of the Hudson River
Valley and into the Catskills and Mohawk Valley between 06Z-09Z.
We tried to account for the dry slot by lowering the PoPs east
of the intense cyclone. Some of the strong southeast to
northeast winds will likely impact the higher terrain in
western New England, and the Taconics and Hudson River valley
corridor shortly before or just after midnight. We have some
flood advisories out, and are monitoring for some some
potential warnings with rain totals up to 3.30" at the
Tannersville NYS Mesonet site in the past 24-hrs with 2.55" in
the 6-hrs. Some isolated thunderstorms are not out of the
question shortly before or just after midnight especially from
the Hudson River Valley south still.
Previous near term....
The latest 12Z NAM/GFS data coupled with some of the HI RES
CAMS are showing an intense and deep cyclone to impact the
region tonight. This will be an unusual storm with it becoming
potentially a sub-970 hPa cyclone moving over the lower Hudson
River Valley by 09Z-12Z. The sfc low looks to go through rapid
cyclogenesis late this afternoon /currently at 20Z on the RAP it
is 991 hPa/ as it lifts north from near Cape Hatteras to
southeast of southern NJ by 00Z/MON...and continues a
north/northwest motion to over the lower/mid Hudson Valley at
03Z or so, and then to the Tug Hill Plateau by 09Z-12Z. The
storm deepens to 965 hPa on the latest 12Z GFS and the NAM has
it lower to 968 hPa! The 12Z ECMWF is not quite as is intense
with a 977 hPa double barrel low pressure system. This storm
will qualify as a meteorological bomb with at least a 25 hPa
fall in pressure in well under 24 hrs. The water vapor loop with
H500 heights overlaid shows the full-latitude trough becoming
negatively tilted. Moisture from Philippe gets entrained in the
system. We have a dual jet streak signature over the East Coast
with the right entrance region over NY and the Delmarva Region
and the left front quad of the equatorward jet streak coming
northward from the Carolinas allowing the meteorological bomb to
form.
An anomalous low-level jet at 925 hPa strengthens to 40-50+ kts
based on the NAM/GFS. The latest 12 GEFS has the +v-component
/southerly/ low-level wind anomalies remain +3 to +4 standard
deviations above normal tonight, and the minus u-component
/easterlies/ remain at -3 to -4 STD DEVS above normal. The
locations from the Capital Region north and east tap into these
wind anomalies overnight. Some of the strong east to southeast
winds may reach the valley locations in the Hudson River Valley
tonight. For example, the latest GFL MAVMOS sustained 10-m winds
are 27 kts, as the intense low passes to the west. The 30 AGL
winds on the NAM/GFS are widespread in the 40-60+ range
overnight. This is the main reason why we posted the High Wind
Warning from the Hudson River Valley eastward. Some of the winds
may gust below 58 mph, but still bring down some large tree
limbs, trees, and power lines. The 850 hPa moisture flux
convergence increases to +5 to +6 STD DEVS above normal as the
tropical moisture streams in on the nose the anomalous low-level
jet. PWATS remain above normal at +1 to +3 STD DEVS above
normal. There may be a few rumbles of thunder with weak elevated
instability over the forecast area especially from the Mohawk
Valley/Capital Region/southern VT south especially prior to
midnight. Rainfall rates may approach or exceed an inch an
hour.The QG lift should continue to increase quickly this
evening with the enhanced moisture advection and favorable upper
level dynamics.
Locations west of the Hudson River Valley...the High Wind
Warning begins at Midnight, and we kept it going until 6 pm Mon.
The better wind gusts may occur in these areas after daybreak
with the cold advection and the strong rise/fall isallobaric
pressure couplet in the wake of the meteorological bomb. The 850
hPa winds increase to 50-70+ kts. The BUFKIT profiles show the
potential for strong/damaging winds to mix down from a couple
thousand feet AGL, and strong funneling down the Mohawk Valley.
The wind gusts are more marginal for the mid Hudson
Valley/northwest CT but we felt there is some concern for downed
trees/tree limbs with the soaked ground even with winds gusts
below 58 mph. This storm system will likely have a large
societal impact on the region in terms of the strong to
potentially damaging winds and heavy rainfall.
The heavy rain/flash flood or main stem river flood threat will
continue tonight into tomorrow. The Flash flood Watch continues.
The forecast rainfall amounts are generally 1.5 to 4 inches
with some 5+ inch amounts in the eastern Catskills due to the
orographically enhanced east to southeast flow. Some
enhancement is also possible along the western New England
higher terrain, such as the southern Greens/Berkshires/Litchfield
Hills where some 3+ inch amounts are not out of the question.
Also the southeast to northeast flow with the sfc wave passing
west of the Hudson River Valley will allow for some enhanced
rainfall amounts along the east facing slopes of the southern
Adirondacks. The favorable moisture advection and tropical
connection from the subtropics and Philippe will allow for the
periods of rain to continue most of the night.
Some reduced rainfall amounts of 1.5 to 2 inch amounts are
expected for areas north and east of Albany in the upper Hudson
Valley, where downsloping/shadowing will occur. These locations
may be prime for some stronger winds to mix to the sfc tonight.
Embedded convective elements will locally enhance rainfall as
well tonight with some strong/damaging winds mixing to the sfc.
The flash flood threat remains in place until noon tomorrow. A
dry slot to the system may quickly move into the region as the
sub-970 hPa low moves over northern NY. Lows tonight will fall
off some towards daybreak with mid 40s to lower 50s with some
upper 30s to lower 40s west of the Hudson River Valley with cold
advection spilling in.
The steady rain diminishes tomorrow morning from the
south/southeast to the north/northwest, as the intense cyclone
moves over southern Quebec. There will continue to be a river
response and we will have to watch for some main stem river
flooding. As stated earlier, the H850 winds increase to 50-70+
kts with strong/damaging winds impacting most of the region. The
wind gusts may be in the 40-60 mph range as far south as the
mid- Hudson Valley/NW CT but again power outages due to down
limbs/trees are possible. The rise/fall isallobaric pressure
couplet on the GFS shows 12-20 hPa pressure rises in 6 hours in
the late morning through the early afternoon. Past CSTAR
research has shown with these intense storms in the cold
advection, deeper mixing occurs with the storm moving into
southern Quebec. The final result is the deeper mixing potential
with some wind gusts of 50-60 kts impacting parts of the
region. The high wind warning goes until 6 pm. It may be dropped
in the southern most zones earlier if the sfc pressure gradient
weakens, and the stacked cyclone drifts further north.
Max temps will not rise much with the cold advection occurring
with highs only in the mid 40s to mid 50s. Clouds will mix with
some sun in the afternoon, but the westerly flow will favor some
lake effect rain and possibly snow showers for the western
Adirondacks in the mid to late pm. We kept some chc/likely pops
in for the western Adirondacks.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
The potential for lake effect rain/snow showers will increase
Monday night into Tuesday, as colder air aloft continues to
filter in over the relatively warmer Great Lakes. Boundary layer
temps should get cold enough for some minor snow accumulation
mainly north of Old Forge and Route 28 late Monday night into
Tuesday morning. Lake effect snow showers will change to rain
during the day Tuesday as the boundary layer warms. With a W-SW
flow regime, most of the lake effect activity should be confined
to the western Adirondacks with dry and seasonably cool
conditions elsewhere. Lows Monday night will be in the 30s to
around 40 with highs on Tuesday in the upper 30s to mid 50s.
After a chance for some lake effect rain and snow showers into
the southern Adirondacks Tuesday night, mean upper trough axis
holds west of our region while slowly lifting and deamplifying.
Little upper impulses track quickly through the broad cyclonic
flow within the upper trough making for some potentially
unsettled weather through the entire period of Tuesday night
through Wednesday night.
The boundary layer thermal gradient lifts north Wednesday into
Wednesday night with some low level wind energy and isentropic
lift supporting chances for showers.
There will be periods of dry weather but the quick upper flow
is causing some differences in sources of guidance and ensembles
as to the timing, strength and moisture of the upper impulses.
So keeping most of the area with a mostly cloudy sky and chances
for showers but some periods of more isolated coverage as well.
Lows Tuesday night will be in the upper 20s to mid 30s with highs
Wednesday in the 50s with some mid to upper 40s southern
Adirondacks. Lows Wednesday night will be in the 30s to lower
40s.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A couple of disturbances rotating through fast mid/upper level flow
will bring chances for precipitation during the long term. Model
consensus favors Thursday and Friday for rain chances, followed by
brief high pressure Friday night and possibly another rain-producing
system for the weekend. For now, thermal profiles look to favor rain
as the p-type. Temps look to average above normal for Thursday and
Friday and getting knocked back down toward normal by Saturday.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Low pressure system will rapidly intensify as it moves up the
Eastern Seaboard tonight. Copious tropical moisture will allow
precipitation to continue, heavy at times through around 06Z.
Flight conditions will trend toward IFR through 04-06Z in cigs
and vsby. An isolated rumble of thunder is possible. A dry slot
looks to track south to north through the terminals around
04-07Z, which should allow precipitation to lighten in
intensity with vsby and cigs improving. Conditions will trend
back toward MVFR late tonight and VFR toward morning.
Winds will be a major concern with this strong system. First,
low-level wind shear is ongoing with winds at the 2kft level
around 50 kt. Winds will tend to become gusty as we go on into
the night, with some of the higher winds likely mixing down to
the surface once the dry slot passes. Gusts to 35-50 kt out of
the east-southeast are possible mainly after 04Z, possibly
earlier at KPSF. Confidence with the occurrence of these strong
gusts is somewhat low.
Winds will back to the south late tonight and eventually to the
southwest Monday morning as the low continues to intensify and
moves north of the region. After 12Z is likely when the winds
will become strongest, with strong and potentially damaging gusts
to 45-55 kt likely at KALB/KPSF, somewhat lower at KPOU/KGFL.
Winds should eventually come down a bit late in the TAF period.
Outlook...
Monday: Very High Operational Impact. High Winds Likely SHRA.
Monday Night: Low Operational Impact. Breezy NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: Moderate Operational Impact. Chance of SHRA.
Thursday: Moderate Operational Impact. Chance of SHRA.
&&
.FIRE WEATHER...
A low pressure system will develop near the North Carolina
coast early this evening and rapidly intensify as it tracks
into the Northeast tonight into early Monday. The system will
tap into tropical moisture, with the rain becoming heavy at
times this afternoon into tonight. Strong winds capable of
damage will develop over western New England and eastern New
York tonight. As the storm system moves north on Monday, strong
damaging westerly winds will impact much of the area as colder
air filters in. Rain will diminish from south to north on
Monday.
&&
.HYDROLOGY...
A Flash Flood Watch remains in effect for all of eastern New
York and western New England from until noon Monday...
A widespread moderate to heavy rainfall will continue across
the HSA as a significant storm system tracks northward through
the region tonight into tomorrow. Forecast rainfall amounts of
1.5 to 4 inches are still expected, with highest amounts
generally south and west of Albany in the eastern Catskills
where some isolated 5+ inch amounts are possible. The higher
terrain of the eastern Catskills, eastern Adirondacks, eastern
Berkshires, Litchfield Hills and southern Greens will receive
the higher amounts on the range. The period of heaviest rainfall
will be tonight.
Excessive rainfall with rates up to one inch per hour at times,
could lead to flash flooding of urban, poor drainage, and low
lying areas, as well as small streams. Leaves clogging storm
drains is another concern that could lead to flash flooding in
urban areas. Isolated thunderstorms are also expected from the
Mohawk Valley and southern Vermont south, which will locally
enhance rainfall rates. Some main stem river flooding will also
be possible over portions of the southern Adirondacks, Mohawk
Valley, eastern Catskills, and possibly portions of western New
England including Bennington on the Walloomsac, Williamstown on
the Hoosic and Brookfield on the Still River. The rain will
taper off Monday morning with still some river responses.
Mainly dry conditions will then return through the middle of
next week, except for lake effect rain/snow showers over the
western Adirondacks. The next chance for widespread
precipitation will be Wednesday night into Thursday.
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...Flash Flood Watch through Monday morning for CTZ001-013.
High Wind Warning until 6 PM EDT Monday for CTZ001-013.
NY...High Wind Warning from midnight tonight to 6 PM EDT Monday for
NYZ032-033-038>040-047-048-051-058-063-082.
Flash Flood Watch through Monday morning for NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
High Wind Warning until 6 PM EDT Monday for NYZ041>043-049-050-
052>054-059>061-064>066-083-084.
MA...Flash Flood Watch through Monday morning for MAZ001-025.
High Wind Warning until 6 PM EDT Monday for MAZ001-025.
VT...Flash Flood Watch through Monday morning for VTZ013>015.
High Wind Warning until 6 PM EDT Monday for VTZ013>015.
&&
$$
SYNOPSIS...Wasula
NEAR TERM...Wasula
SHORT TERM...11/NAS
LONG TERM...Thompson
AVIATION...Thompson
FIRE WEATHER...11
HYDROLOGY...JPV/Wasula
Area Forecast Discussion
National Weather Service Burlington VT
1045 PM EDT Sun Oct 29 2017
.SYNOPSIS...
Strong and damaging wind event expected for parts of the North
County late tonight into Monday with scattered to widespread power
outages possible...especially along the Western Slopes. Periods of
rain...heavy at times will continue overnight with minor flooding
possible. Storm system will slowly lift north of the region by
Monday Night with lighter winds...cooler temperatures...and drier
weather expected by Tuesday.
&&
.NEAR TERM /UNTIL NOON MONDAY/...
As of 1044 PM EDT Sunday...Forecast still on track. Seeing VAD
wind profile showing up to 60 kt as low level jet is increasing.
Heavier rain moving northward may drop an inch or so of rain in
the next few hours before a dry slot moves in after 06z. This
should help wind gusts to increase overnight with near hurricane
gusts upwards of 70mph possible in downslope wind locations
west of the Green mountains.
Winds still fairly light in the immediate Lake Champlain region
of the valley while downslope wind gusts 40-50mph have occurred
along the western slopes of the Greens. See our latest Public
Information Statements (PNS) for the latest reports.
Mountain wave activity seen nicely on the radar base velocity
with wind speeds exceeding 50 kts. This is just a taste of
things to come. Highest resolution models have best handle on
the mountain wave phenomena as local BTV 2km, its time lag,
HiResARW, and HRRR has best handle on wind gusts which are
confined to a very small area west of the mountains at the
moment. They are in general agreement that the highest winds
will occur when the low level jet maxes out between 06-12z with
the core of the jet of 90-105kt 3-5k feet. Froude numbers
running just over 1 indicative of downslope wind storms. The
Froude creeps a bit over 1 during the core of the jet so
expecting wind gusts to increase over a larger area causing an
increase in power outages by 09z.
High wind warnings and advisories continue for entire forecast
area from this evening through Monday. See Non-precipitation
produce for specific details.
Localized wind gusts to 70 mph possible tonight along the western
slopes from near Rutland to Underhill to Enosburg with scattered to
widespread power outages possible. Also...gusts 50 to 60 mph
possible on the VT side of the CPV tonight...with widespread gusts
up to 50 mph on backside for Monday. High wind warnings and
advisories have been posted to highlight power outages and expected
tree damage.
Synoptic scale shows deepening 980mb low pres near KACY this
evening...tracking north toward KBGM by 06z and near KMSS as a 970mb
low by 12z Monday. Well advertised 850mb southeast jet of 80 to 90
knots continues to shift from south to north across our cwa between
00z and 15z Monday. High resolution data shows the classic MSLP
couplet developing along the western slopes...along with a 925mb to
850mb omega couplet on lee side of green mountains. Sounding data
continues to show mixed signals on the amount of mixing...but BTV
4km/2km and NAM 3km show bottom of the mixed layer winds of 45 to 55
knots possible...with localized higher amounts in downslope regions
tonight. Also...noted strong mixed layer winds at Newport and parts
of the higher trrn of central/eastern vt...so warnings and
advisories look reasonable. Expecting scattered to widespread power
outages...along with tree and minor property damage possible. As dry
slot develops toward 06z...expect mixing of stronger winds to
develop from south to north across our cwa...with pulse like bursts
of stronger winds likely.
Interesting mesoscale feature develops btwn 09-12z Monday morning
associated with potent 5h vort rounding closed 5/7h circulation.
This potent energy...combined with surface boundary with winds
shifting from southeast to northwest to produce a fine line of low
top convection from eastern dacks into the cpv. High resolution
guidance continues to show potential for damaging winds to develop
along this convective fine line boundary on Monday Morning...with
localized gusts to 60 mph...especially over the warmer lake
champlain waters where better mixing could occur.
As 970mb low pres lifts into southern canada on Monday...20 to 24mb
6 hr pres rise couplet develops over the cwa and gusty southwest to
west winds develop. Expecting strongest winds over the SLV/eastern
Dacks and parts of central/eastern and northern Vt...with additional
gusts up to 50 mph possible. As cold air advection develops and low
levels dry out...mixing heights will increase...support localized
wind gusts to 50 mph with additional power outages likely.
Still anticipating a band of moderate to locally heavy rainfall
tonight btwn 00z and 08z tonight...before well defined mid/upper
level dry slot and downslope winds increase. NAM/GFS/RAP continue to
show strong 850 to 700 mb fgen forcing...along with nose of low
level jet helping to enhance convergence/moisture advection. Expect
rainfall totals of 0.50 to 1.5 inches with this band. Storm total
precip will range from near 1.0 NEK/CPV to 1 to 2 inches se upslope
of the dacks/southern greens to 3 or 4 inches western dacks/slv.
Temps will be very tricky with boundary nearby tonight and
associated developing southeast winds. Thinking lows mainly in the
50s east to m/u 40s west...with some values rising toward after
midnight as winds continue to increase. However...as sharp boundary
with low top showers develops from southwest to northeast on Monday
morning...expect a sharp 10 to 15 degree drop in temps...with very
gusty winds.
&&
.SHORT TERM /NOON MONDAY THROUGH TUESDAY NIGHT/...
As of 245 PM EDT Sunday...Cold air advection pushes in to the CWA
Monday night into Tuesday. This push temperatures back near
seasonal normals and bring fall like weather back to the the
region. Strong southwesterly flow across Lake Ontario will bring
about some lake effect showers. This band will waver across the
southern halves of St Lawrence and Franklin counties.
Temperatures will cool enough that some of the rain could mix
with snow in the highest elevations both Monday and Tuesday
night. Expect high temperatures for Tuesday in the mid 40s to
mid 50s, while overnight lows for Monday and Tuesday will be in
the 30s with higher elevations dropping into the 20s.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 245 PM EDT Sunday...Cyclonic flow dominates through the
period with a few embedded shortwaves or fronts that are the
focus of any precipitation.
The first is a shortwave and surface low moving across the Great
Lakes on Thu/Fri with warm frontal showers possible Thu then cold
frontal showers Friday...ending west to east during Friday with
falling temperatures during the day.
Discrepancies for late Sat/Sun with a chance of showers
possible with a weak disturbance to our southwest trying to ride
the upper flow into the northeast while ridging takes place in
northern areas.
Right now...best chance of any showers would be southern areas.
Temperatures largely above normal thru period with Saturday being
cooler than normal. Still real no cold as temps should stay above
freezing for Champlain Valley thru the period.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Through 00Z Tuesday...A mix of VFR/MVFR/IFR conditions will
continue through the period as various rounds or rain move
through the region. Every station will see varying conditions
that can last for a few minutes to a couple of hours. After 18Z,
stations should start to see steady improvement back to VFR.
Winds are currently in a lull, but will begin to pick up at
most stations from the southeast at 15-30 knots. This will begin
a continual ramp up of winds, peaking during the 08Z - 14Z time
frame with sustained winds in the 15-25 knot range and gusts as
high as 50 knots at KRUT, with all other locations in the 30-45
knot range. In the brief periods that the winds do lull again
during this time period, expect to see wind shear conditions at
2000ft at 40-55 knots. Even after 14Z winds will still remain
gusty through the period.
Outlook...
Monday Night: VFR. Breezy. Chance SHRA.
Tuesday: VFR. Breezy. Slight Chance SHRA.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. Slight Chance SHRA...Slight Chance SHSN.
Wednesday Night: VFR. Chance SHRA.
Thursday: VFR/MVFR. Likely SHRA.
Thursday Night: VFR. Chance SHRA.
Friday: VFR. Slight Chance SHRA.
&&
.HYDROLOGY...
As of 823 PM EDT Sunday...QPE estimates through 00Z from MRMS
running from as little as 0.25 in the northeast kingdom of VT to
over an inch in the far western part of St. Lawrence
Valley and far southern VT.
Banded heavy rain moving onshore in southern New England as
low pressure near KACY really cranking up. Still expecting
another 1-2" of rain overnight, possibly locally heavier in SE
upslope flow.
No river rises noted yet, but rain will cause rises on local
streams and rivers with some gages possibly approaching action
stage by Monday. Some minor urban street flooding is possible
from leaves clogging storm drainages, especially in areas of
heavier rainfall rates on tonight. At this time the only river
that may reach flood stage is the Ausable. Storm total precip
will range from 0.75 to 1.50 with localized amounts over 2.0
inches in VT and up to 3 or 4 inches over the Saint Lawrence
Valley in NY.
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 at http:/weather.gov/btv/rivers
&&
.MARINE...
Lake wind advisory for southeast winds increasing 30 to 40 knots
tonight with localized bursts up to 50 knots possible on Monday
morning. These winds quickly shift to the southwest and west by
mid morning Monday...before slowly weakening to 15 to 25 knots
by Monday Night. Waves build 3 to 6 feet tonight.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Flash Flood Watch through Monday morning for VTZ011-012-019.
High Wind Warning until 11 AM EDT Monday for VTZ002>006-009-
011-016>019.
Wind Advisory until 8 PM EDT Monday for VTZ001-007-008-010-012.
NY...Flash Flood Watch through Monday morning for NYZ026-027-
029>031-034-087.
Wind Advisory from 6 AM to 8 PM EDT Monday for NYZ026>031-034-
035-087.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Taber/Sisson
SHORT TERM...Verasamy
LONG TERM...SLW
AVIATION...Verasamy
HYDROLOGY...Taber
MARINE...Taber
Area Forecast Discussion
National Weather Service Caribou ME
1106 PM EDT Sun Oct 29 2017
.SYNOPSIS...
Intense low pressure will track to our west overnight through
Monday bringing strong winds. The low will continue north
through Quebec Monday night into Tuesday as strong gusty winds
continue behind the low.
&&
.NEAR TERM /THROUGH MONDAY/...
1055 PM Update...
Radar showed a band of rain moving nw across the downeast and
central areas. This area will continue to lift nw over the next
few hrs. The more steadier rainfall is yet to come and looks
like it will overspread the region from south to north by early
morning. Some of this rainfall will be heavy at times. Winds are
slowly picking up across the southern portion of the state
w/gusts to 40 mph at KPWM(Portland). This wind will move north
overnight and increase into Monday morning. High Wind Warnings
remain in place.
Temps had leveled off earlier and are starting to warm again as
waa hits as shown on the 00Z UA. Sfc analysis showed the low
intensifying low e of NJ lift nnw. The latest NAM and RAP show
the low lifting into the Hudson River Valley overnight. This is
picked up well by the latest HRRR. Temps/dewpoints were adjusted
to fit the latest conditions w/the warm up.
Previous Discussion...
Intensifying low pressure combining a deep trough to our west
and tropical storm Philippe off the Southeast coast will track
north into the Hudson Valley tonight. The tightening gradient
between the strong low and high pressure to our east will bring
increasing winds overnight with very strong winds expected
across the area from late tonight through Monday. The strongest
winds Downeast and along the coast will be early Monday morning
with the highest winds further north during the morning and
midday. A high wind warning remains up for the entire area late
tonight through Monday. The storm will bring a windswept rain
tonight into Monday with amounts ranging from an inch north to
two inches in west central locations.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
Low pressure wl hv lifted north twd Hudson Bay by the beginning of
the short term pd. May see a few lingering showers acrs the north as
cyclonic flow conts in the evng. Skies wl clr fm south to north drg
the ovrngt hrs hwvr with low-lvl moisture rmng acrs the north
expect pcldy skies on Tue. Gusty sw winds cont on Tue leading to
temps once again abv normal as minimal caa wl exist.
Hipres wl build south of the area Tue night into Wed with sw flow
aloft. H8 temps wl drop thru the end of the short term with temps
Tue night and Wed just slightly blo seasonal norms.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Next system wl wrap up to the west Wed night and spread rain,
and possibly snow showers in the St. John Vly, into CWA by Thur
morning. Temps quickly rise in the morning with all rain during
the day. System wl bring cold front thru Fri night with colder
air expected for Sat. May see isold snow showers Sat morning
acrs the north bfr finally heading north and east. Hipres wl
quickly follow for the first half off the weekend.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR to LIFR conditions are expected tonight through
Monday with very strong winds from late tonight through Monday.
Some wind shear is likely for SSE winds up to 50 kt at 2K ft.
SHORT TERM: VFR conditions expected Mon night as low pressure
pulls off to the north. Gusty southwest winds will continue
through Tue evening. VFR expected through Wed night before
lowering to MVFR in showers Thursday through the end of the
week.
&&
.MARINE...
NEAR TERM: Powerful low pressure lifting to our west is expected
to bring strong winds, and wind gusts up to hurricane force,
very late tonight into early Monday morning. The tightest
gradient across the waters is expected to occur around, or just
before dawn Monday morning. A hurricane force wind warning is
being issued for the offshore waters from 2 AM to 8 AM with a
storm warning for the intracoastal waters. Seas are expected to
quickly build to over 20 feet early Monday morning in response
to the strong winds.
SHORT TERM: Expect storm conditions Mon morning into the
afternoon hours before diminishing to gales and remaining high
through Tue morning. SCA conditions will continue through the
middle of the week as winds and seas remain high.
&&
.TIDES/COASTAL FLOODING...
Current storm surge models forecasting 1.5 foot storm surge
however expect this to be closer to around 2 feet since the
storm surge models are based on GFS wind forcing and forecaster
winds are a little higher than model winds. In addition, off-
shore wave heights of up to 28 feet and breaking wave heights in
the surf zone of up to 14 feet are expected. Will issue a
Coastal Flood Statement for splash-over and minor beach erosion.
Astronomical high tides Monday Morning are well below the
highest levels of the month. Therefore concern over coastal
flooding is greatly reduced. However with large breaking waves
in the surf-zone some minor splash over or overtopping in
exposed areas can be expected. In Machias storm surge is
expected to be a little higher (2.5 feet) due to the convergent
shape of the Machias Bay, so with the astronomical tide of 11.8
feet combined with the storm surge, water levels are still
expected to stay below the critical flood level of 16.93 feet
MLLW.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...High Wind Warning from 2 AM to 8 PM EDT Monday for MEZ001>006-
010-011-031-032.
High Wind Warning from 2 AM to 2 PM EDT Monday for MEZ015>017-
029-030.
MARINE...Storm Warning from 2 AM to 8 AM EDT Monday for ANZ052.
Hurricane Force Wind Warning from 2 AM to 8 AM EDT Monday for
ANZ050-051.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Cleveland OH
931 PM EDT Sun Oct 29 2017
.SYNOPSIS...
Deep low pressure near New Jersey will track north into Quebec on
Monday helping to pull several reinforcing cold fronts southeast
through the area Monday and Tuesday. High pressure will briefly
spread north into the region for Wednesday before moving off to the
northeast. Another cold front will push east across the area
Thursday night with high pressure spreading southeast into Lake Erie
by Friday night.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
Through the near term our weather will be dominated by cold flow
over the lake, deep low pressure moving north into Quebec Monday and
another cold front dropping SE across the area Monday.
For tonight, the main concern will be lake effect rain showers,
possibly mixed with a little snow inland. Flow will be backing
through the night. The shifting flow and fringe subsidence from the
east coast system have combined to temporarily end almost all of the
lake effect shra. Even though the HRRR currently has more lake
effect activity than reality, do see some support for a weak band of
shra with a Lake Huron connection to redevelop late tonight in the
NE OH snowbelt before shifting into NW PA by 12z.
Any partial clearing in the west tonight will be gone by Monday
morning with increasing moisture from the west ahead of the next
reinforcing cold front. Lows tonight in the 30s so did allow for a
possible mix away from the lake.
On Monday, will go with low chance pops for showers in general due
to the cold front. Expect lake effect to be increasing through the
day on Monday as moisture and colder air move in from the west and
winds line up for a long fetch. In southwest flow, expect the
primary band to be off shore possibly skimming the ERI lakeshore.
Monday night colder air continues to pour in and winds begin to veer
to more of a westerly direction the first half of the night. BUFKIT
suggests extreme instability from the warm lake. Through the evening
and the first half of the night brought the band inland with
categorical pops for the traditional snow belt. Towards morning
winds back to southwest pushing the band off shore. With lows in the
30s did bring in a light accum Monday night inland Ashtabula Erie
and Crawford counties.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Between Tuesday and Wednesday we will transition temporarily away
from the persistent cyclonic flow as high pressure passes from the
lower Ohio Valley to the mid-Atlantic. This will take the lake
effect activity out of northwest PA/far northeast Ohio depending on
timing of the shift in the flow. For now continued precip chances
across the extreme east snowbelt through Tuesday night. There is
enough variability in guidance to produce a decent spread in precip
chances and temperatures Tuesday and Tuesday night. For now have
gone toward a national blend and following the recent trend of
pulling back on precip chances Wednesday but bumping them up
Wednesday night and lingering them into Thursday. Daytime highs will
be cool Tuesday and Wednesday with no real air mass change until
Wednesday night/Thursday. Night lows Tuesday night may vary if we
can get a brief window of clearing and decoupled winds. Thursday
will be more seasonable with a south-southwest wind.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Not many changes to the long term from the earlier forecast. Similar
to yesterday the models start out in fair agreement and then diverge
during the period. Both the GFS and ECMWF drag a cold front across
the area Thursday night with precip chances increasing ahead of this
feature. Have gone ahead and bumped precip chances to likely over
much of the area. The showers should end from west to east Friday
morning with the models then having differing ideas when precip will
return to the area. Similar to yesterday the ECMWF shows a stronger
high building into the region which keeps the area dry into
Saturday. The GFS quickly bring showers back to the area with a warm
front on Saturday while the ECMWF shows better chances Saturday
night. Will go with some low chance pops for now Saturday and
Saturday night but will again dry things out on Sunday. Temperatures
will start out the period near normal but will try to sneak back
into the 60s by Sunday.
&&
.AVIATION /00Z Monday THROUGH Friday/...
Conditions should improve from west to east tonight as winds back to
SW bringing drier air in from the west for a while. With potential
for lake effect shra and lower clouds will be slow to improve YNG
and ERI above MVFR until around or after daybreak.
Reinforcing cold front will drop SE across the area Monday causing
SW winds to veer to west while increasing to be gusting 25 to 35
knots. Sct shra will probably work SE across the area with the front
but should only lead to brief effects on any airport. Most of the
lake effect shra should try and stay just north of ERI until near
sunset when they should start pushing inland.
OUTLOOK...Non-VFR in the vicinity of ERI with lake-effect showers
near the lakeshore Monday night into Tuesday. Non-VFR redeveloping
area wide for Wednesday into Thursday.
&&
.MARINE...
Winds will veer around to the southwest and a substantial increase
Monday is expected as low pressure deepens along the east coast and
moves across New England and to Quebec. Highest confidence in Gales
resides across the far east end of the lake for late tonight through
the better part of Monday where the strongest winds could mix down.
Otherwise with the low a bit removed from the lake and neutral
temperature advection, Gales across mid lake will be more
intermittent and marginal. With Gale Watch out previously and Gale
Warnings posted across all of the Canadian waters, have hoisted the
Gale Warning for the eastern half of the lake. Small craft advisory
west of the Gales now in place across the remainder of the nearshore
waters. Winds subside for Tuesday night into Wednesday as high
pressure makes its closest pass shifting across the Ohio Valley. The
remainder of the week will feature the next low tracking across the
northern lakes with increasing southwest flow Thursday followed by a
shift to the north behind the cold front early Friday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory from 8 PM this evening to 5 AM EDT Monday
for LEZ147>149.
Gale Warning from 5 AM Monday to 5 AM EDT Tuesday for
LEZ147>149-167>169.
Small Craft Advisory from 10 AM to 10 PM EDT Monday for LEZ142-
143.
Small Craft Advisory from 8 PM this evening to 2 AM EDT
Wednesday for LEZ144>146.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/Adams
SHORT TERM...Oudeman
LONG TERM...Kubina
AVIATION...Adams
MARINE...Oudeman
Area Forecast Discussion
National Weather Service State College PA
1137 PM EDT Sun Oct 29 2017
.SYNOPSIS...
A developing East Coast storm will impact central PA through
tonight with moderate to heavy rainfall and strong gusty winds.
As colder air wraps into the departing system, rain will likely
mix with or change to wet snow late tonight into early Monday
over the higher elevations of the Alleghenies. Temperatures
should gradually moderate with wet weather possible into the
second half of the week.
&&
.NEAR TERM /THROUGH MONDAY/...
Flash Flood Watch remains in effect for my northeastern
counties late this evening with still 2 to 4 more hours of
moderate to heavy rainfall. HRRR conts to bring locally 2"+
amounts through 2 AM, with locally higher amounts over Sullivan
County. This on top of 1-2"+ which fell last night into today
and caused highly localized minor small stream and poor drainage
flooding earlier in the day.
Rapid cyclogenesis and strong southeast to easterly low level
flow over the northern Mid Atlantic is pushing dry slot rapidly
northward into southeast PA at this hour, and this will spell
the end of the heavy rain threat for my northeastern counties by
07z. The deepening consolidated surface low is expected to
track north- northeast overnight to a position just west of
Montreal, Canada by 12z Monday morning.
Rain changing to snow on schedule down to ~3k feet in the WV/MD
panhandles and highest peaks of the Laurel Highlands are
seeing the changeover mid to late evening. Added a few more tenths
of an inch above 1500 feet to going snow totals there, with
some areas see an inch or a little more at the highest peaks.
As rainfall begins to end early Monday, strong gusty winds will
sweep colder air into the area. Max wind gusts in the 40-50 mph
range are forecast and could result in downed tree
limbs/branches and isolated power outages. The wind advisory was
expanded to include the entire CWA.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
The weather will begin to calm down Monday night as the storm
moves into Canada and we see the NW winds diminish. Lows will
drop into the lower 30s. Any showers over the far NWRN zones
associated with the cool cyclonic flow across the lakes will mix
or change over to snow showers. No accum is expected. By
Tuesday the region will be between the cool cyclonic flow to our
north and high pressure off to our SW. If there is a shower, it
will favor the areas just downwind of Lake Erie, but the best
chance will be north of the border. From Central PA down into
the Lower Susq Valley, it will be dry with partly to mostly
sunny skies and high temps in the low to mid 50s. Continued
fair weather Tuesday night as high pressure moves across PA.
Temperatures will drop down into the mid 20s northwest to low
30s southeast.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
By Wednesday afternoon, the surface high will begin to slide
east off the coast, paving the way for a series of weak
short-waves to speed toward the region in the fast WSW flow
aloft. The chance for rain will return before the day is over
and we will have the chance of scattered showers remaining in
the forecast into Friday when a weak cold front should bring at
least a brief break Saturday. The model blended POPs are not
optimistic for any kind of significant drying hanging around too
long however as the flow aloft remains strong quasi-zonal, with
the potential for weak impulses racing our way along the
northern tier of the US right through Sunday.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
An intensifying storm moving up the east coast will bring rain,
heavy at times, to the region late this evening, with strong
northwest winds lasting into Monday. Rising cigs noted across
the region late this evening, as winds have shifted to the
northwest, resulting in downsloping/drying at low levels. This
will not be the case at KBFD/KJST, where northwest winds ascend
the higher terrain, locking in the IFR cigs until late tonight.
Bufkit soundings support increasing winds overnight with
frequent gusts of 30-40kts likely after midnight into early
Monday.
The pattern will remain blustery into Monday but model soundings
indicate lingering MVFR cigs at KBFD/KJST will give way to
widespread VFR conditions during the afternoon.
Outlook...
Tue...No sig wx expected.
Wed...Slight chance of PM showers/reduced cigs.
Thu...Showers/reduced cigs possible KBFD.
Fri...AM showers/reduced cigs possible KBFD/KJST.
&&
.HYDROLOGY...
Streams and rivers across central PA will experience significant
rises into Tuesday. Smaller streams and creeks are starting to
respond and will remain most susceptible to minor flooding. No
river flooding is currently forecast for larger main stem rivers
although some are projected to crest near to above
caution/action stage.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 8 AM EDT Monday for PAZ037-041-042-046.
Wind Advisory until 2 PM EDT Monday for PAZ004>006-010>012-
017>019-024>028-033>037-041-042-045-046-049>053-056>059-
063>066.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...DeVoir/Steinbugl
SHORT TERM...Watson/La Corte
LONG TERM...Watson/La Corte
AVIATION...Fitzgerald
HYDROLOGY...
Area Forecast Discussion
National Weather Service Cheyenne WY
530 PM MDT Sun Oct 29 2017
.SHORT TERM...(This evening through Monday night)
Issued at 143 PM MDT Sun Oct 29 2017
Strong cold front currently pushing south through our northern
counties. As the flow becomes more northerly and northeasterly
behind the front, seeing some low cloudiness developing in favored
upslope locations to our north along with some light
precipitation. This trend should continue southward through this
evening along with cooling temperatures in a brisk north wind.
Temperatures will fall to near freezing over SE Wyoming by 9 pm or
so and over western Nebraska after midnight. Precip will likely
start as liquid but quickly change over to light snow and/or
freezing drizzle late this evening. Not much in the way of forcing
for ascent other than low level upslope flow and some transient
frontogenesis centered around 700 mb per RAP analysis. The 12Z
sounding from Great Falls earlier today showed a shallow saturated
layer up to around -10C. This airmass doesn`t look to change much
as it heads south so mentioned freezing drizzle in many areas due
to lack of deep saturation and lift in the preferred snow growth
zone. Some areas of fog are likely along the South Laramie Range
near the I-80 summit late tonight and there could be a few travel
impacts in this area with the cold temps/freezing drizzle/light
snow. Nothing that would reach advisory criteria at this time
however.
Monday should feature any lingering precip ending early in the
morning with clouds thinning or even breaking up by the afternoon.
It will be quite cold with temperatures struggling to make it back
to the freezing mark over SE Wyoming and only into the mid/upper
30s over Nebraska. As the surface high slides just to our east on
Monday night, winds should die or become light. Thus should see
temperatures plummet after sunset with lows in the single digits
and teens likely.
.LONG TERM...(Tuesday through Sunday)
Issued at 143 PM MDT Sun Oct 29 2017
Main concern in this period will be the strong northwesterly jet
and associated upper shortwave forecast to dive into the northern
Rockies and high plains on Tuesday night into Wednesday. This
shortwave will induce a 994 mb low over eastern MT on Wednesday
with significant lee troughing extending southward into SE
Wyoming. Low level gradients and winds respond rapidly on Tuesday
night peaking around 75 meters by early Wednesday morning. Both
the NAM and GFS indicate 700 mb winds increasing to 60-70 kt
Wednesday morning. Think high wind headlines are likely for the
wind prone areas of SE Wyoming and possibly even into the Cheyenne
area for Wednesday if this trend continues. After Wednesday, the
area will remain in zonal flow aloft until Friday when significant
troughing is forecast to develop over the NW US. Still much
disagreement amount various guidance in regards to individual
shortwaves and frontal placement. For now, things look mostly dry
until the weekend although breezy to windy most days.
&&
.AVIATION...(For the 00Z TAFS through Monday afternoon)
A cold front is currently pushing southwest across the Laramie
valley this evening and will continue to make progress westward
before it stalls near the mountains. MVFR CIGS are developing from
north to south with KDGW showing CIGS below 3000 feet AGL. Expect
MVFR CIGS to devleop over the next few hours across the area, and
VIS with light precip developing late this evening. Precip may be
light snow, drizzle, freezing drizzle through tonight with VIS
occasionally lowering to near IFR levels at times, mainly around
KLAR and KCYS, although KSNY and KRWL may see these conditions
briefly as well. Conditions are expected to improve shortly after
sunrise, although some fog is possible between 06z to 15z.
&&
.FIRE WEATHER...
Issued at 143 PM MDT Sun Oct 29 2017
It will be cool with some light precip through Monday which keep
fire weather concerns at a minimum. Drier and windier conditions
return by Wednesday although at this time forecasted RH values
remain above critical levels.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...DEL
LONG TERM...DEL/JG
AVIATION...TJT
FIRE WEATHER...DEL
Area Forecast Discussion
National Weather Service Des Moines IA
617 PM CDT Sun Oct 29 2017
.SHORT TERM.../Tonight through Monday/
Issued at 350 PM CDT Sun Oct 29 2017
Light rain looks to persist across northern to eastern sections of
the forecast area during the rest of the afternoon into the early
evening hours. Very weak forcing with this shortwave and still
plenty of dry air below 850mb to contend with, so low confidence
with any widespread measurable rain. Thus, lowered QPF amounts
today. Other change for today was pulled pops further south to
incorporate the DSM Metro as latest few runs of the HRRR/ESRL
HRRR continue to bring the light rain as far south as Highway 34.
Rain looks to quickly push east of the forecast area past 03z
Monday.
Another shortwave, this one much stronger with respect to winds,
pushes across the state by the morning hours Monday. Sharp surface
pressure gradient combined with decent mixing through the day will
provide some blustery conditions Monday. Across the north, have
mention for some brief sprinkles/flurries per saturation within
the dendritic layer at MCW to ALO past 20z. Certainly confident a
few flakes will be generated, but timing of the surface
temperatures cooling enough for flakes to reach the ground is
still questionable. Regardless, confident enough to remove
measurable pops Monday afternoon due to the lack of significant
frontogenetical forcing and still the dry layer below 4kft to
overcome. Winds atop the mixed layer range around 35 knots through
much of the evening Monday and can expect a blustery evening for
Beggar`s Night.
.LONG TERM.../Monday night through Sunday/
Issued at 350 PM CDT Sun Oct 29 2017
The only significant weather producer to discuss looks to be a
cold front and associated surface low pressure to push across the
region on Wednesday. Light snow chances across northern Iowa early
Wednesday within the WAA regime, but the WAA looks to be strong
enough to push temperatures above freezing late in the morning
into the afternoon. However, lack of significant forcing and deep
moisture bodes for low confidence any measurable snow and/or
rainfall Wednesday. The rest of the week remains dry with the next
potential for any precipitation appearing on Saturday.
&&
.AVIATION.../For the 00Z TAFS through 00Z Monday evening/
Issued at 617 PM CDT Sun Oct 29 2017
Clouds and persistent showers will continue through 02-03z east
with brief period of lower cigs reaching MVFR possible north sites
KFOD/KMCW and KALO prior to 06z then becoming VFR conditions
through 13z. Secondary front with increasing mixing/wind and
lowering cigs will move quickly southeast across the region aft
13z. Strong NW winds expected with Hires models also showing
potential for MVFR cigs to return to KMCW/KALO/KFOD between 15 and
18z as cold air advection takes over. Winds will remain strong
through 23z. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Podrazik
LONG TERM...Podrazik
AVIATION...REV
Area Forecast Discussion
National Weather Service Green Bay WI
607 PM CDT Sun Oct 29 2017
Updated aviation portion for 00Z TAF issuance
.SYNOPSIS...
Issued at 216 PM CDT Sun Oct 29 2017
Seasonable temperatures and a few rounds of light precipitation
are expected for the next week.
A very energetic large scale pattern typical of late autumn or
early winter will continue throughout the period. The dominant
upper level feature will be a strong positive upper height
anomaly initially just off the West Coast. It will shift westward
to near the Aleutians by late in the week, then remain in place
through next weekend. The position and amplitude of the eastern
Pacific ridge will strongly influence the downstream flow across
North America. The retrogression of the eastern Pacific ridge
will allow the upper trough currently near 80W to temporarily
reform back near 95W by mid-week, before it takes a more
substantial jump westward to near the West Coast by next weekend.
Once it gets to the West Coast, a broad west-southwest flow
will develop across the mid-section of the country.
The period will begin with temperatures a little below normal,
then readings will rebound to near or a little above normal as the
upper trough shifts west and southwest flow eventually develops.
But it`s still probably going to feel cool to most people after
the recent prolonged stretch of warm weather. Shortwaves and
cyclones moving through the large scale pattern will bring
numerous opportunities for precipitation. Moisture is likely to be
limited for most of the forecast period. Normal precipitation for
a week at this time of year is a little over 1/2 inch, and the
best guess is that most locations will end up close to that.
&&
.SHORT TERM...Tonight and Monday
Issued at 216 PM CDT Sun Oct 29 2017
Clouds were on the increase across the area this afternoon.
Temperatures were in the middle 30s to around 40 north,
and in the lower to middle 40s south.
An upper level disturbance and associated cold front will move
across the area this afternoon. Models a little slower with the
arrival of the precipitation based on the latest HRRR model. Have
back off on precipitation chances across the far east early this
evening, then ramp them up by late evening. Latest HRRR model
depicts more widespread precipitation developing later this evening
across eastern Wisconsin. It is possible that portions of central
Wisconsin could remain dry through the night. Also, latest model
guidance indicated boundary layer temperatures will be a tad bit
warmer than previous thought. This would remain more rain across
east-central Wisconsin, thus do not expect to see any snow across
the Fox Valley/lakeshore region. There will be a more rain/snow
mix across central into far northeast Wisconsin. Across the far
north, think most of precipitation will be in the form with a
small chance of rain. Used a non-diurnal curve with temperatures
not falling off to much this evening, then dropping overnight
behind the passage of the cold front.
Blustery conditions will develop across the area late tonight or
on Monday morning, with windy conditions expected throughout much
of the day. Gusts to around 35 mph are possible across central and
northeast Wisconsin. Precipitation chances will be on the increase
during the day Monday with lake effect snow showers likely across
the far north during the afternoon with small chances of rain/snow
over the remainder of the north. Across central and east-central
Wisconsin, precipitation will be in the form of rain. Did not
stray far from previous forecast for highs on Monday.
.LONG TERM...Monday Night Through Sunday
Issued at 216 PM CDT Sun Oct 29 2017
Lake-effect snow showers are likely in the Lake Superior snowbelt
Monday night. Most of the guidance suggests winds across the
western part of the lake will shift to the NNE behind a cold front
dropping south through the area during the evening. Winds should
back NW during the night, but there is some disagreement among
the guidance on what happens after that. Most of the models keep
backing the winds, to W by some point Tuesday morning. That would
result in a limited duration of the favorable trajectories for
Vilas county. A few of the hi-res models (Canadian, the hi-res
WRFs) hold onto favorable trajectories a little longer, but even
on these models the period with a favorable trajectory is limited.
But trajectory isn`t the only limiting factor. Large scale
subsidence is also likely to be setting up over the region as a
shortwave departs the region. These factors suggest maintaining
the course of previous forecasts which means keeping high PoPs for
snow showers, but having only light accumulations.
After a lull in the precipitation chances once the lake-effect
ends, another cyclone will track eastward across southern Canada
Wednesday into Thursday. The GFS looked too aggressive with the
coverage/amount of precipitation it generated. Preferred to keep
the higher PoPs and QPF across the north, where it`s more likely
the lift will result in saturation. That fits well with the new
ECWWF. Precipitation type could again be an issue, so stuck with
mainly a mix/snow across the north and rain south.
The potential for a more substantial precipitation event looms
toward the end of the period as southwest upper flow develops
next weekend. But models still differ on the details of the
pattern, so we`ll need to wait until closer to the event for the
specifics to become apparent.
Given the changeable pattern and model differences, few changes
were made to the standard forecast initialization grids.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 603 PM CDT Sun Oct 29 2017
An upper level disturbance will track across the area tonight,
bringing a mix of rain and snow to the TAF sites. Mainly snow is
expected across the north, with mainly rain over east-central
Wisconsin with a mix elsewhere. There will be a break in the
precipitation across much of the area except over the far north
late tonight into Monday morning. Precipitation chances will
gradually increase and spread southward during the day Monday as
northerly flow gets established. Lake effect snow showers across
the north, with a mix of rain/snow showers central into far
northeast Wisconsin with mainly rain showers across the Fox
Valley/lakeshore region.
CIGS are mainly expected to be VFR, with conditions falling to
MVFR in showers. Conditions expected to eventually fall to MVFR
across the north and west later tonight into Monday. Gusty west
winds to 30 knots are possible across central and east-central
Wisconsin with winds a tad bit lower across the north on Monday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....Eckberg
LONG TERM......Skowronski
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Gray ME
1118 PM EDT Sun Oct 29 2017
.SYNOPSIS...
Intense low pressure will track northward through the Hudson
River Valley tonight, bringing a period of heavy rain and strong
winds to much of New England. Coastal areas will be hardest hit
by the wind, while the mountains will be hardest hit by the
rain. As the low moves north, a cold front will sweep westward
across New England Monday morning, ushering in colder, drier air
on a stiff westerly wind. The westerly winds will continue but
gradually decrease in intensity through Tuesday as high pressure
builds in from the southwest. The next frontal system will
arrive late next week bringing another chance of rain, but not
as heavy this time.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
1115 PM Update...Winds continue to ramp up at this hour with
peak gusts between 35 and 40 knots. These will continue to
increase overnight before peaking just ahead of the nose of the
dry slot around and just prior to dawn. This is also when the
leftovers of Philippe move up through western ME and NH. There
may be a brief extra burst of winds on the east side of that
feature as well. Overall, wind and flood headlines remains as
is. Wind gusts of 40 to 60 MPH are still expected...with the
highest values on the coastal plain and w/nw slopes of the
Whites. Not out of the question that someone on the immediate
coast sees a 70 MPH gust late tonight in convection. Otherwise,
100% PoP for the next several hours as rain increases in
intensity as anomalous PWAT air streams northward.
9 PM Update...Have updated PoPs for the next few hours across
central and northeastern portions of the CWA as dry air is
holding the rain back. It`ll fill by midnight most areas.
Otherwise, winds continue to gradually ramp up this evening. As
per a plethora of forecast sounding data, a gradual ramp-up will
continue for the next 6 hours or so and then probably pop into
that 45-60 mph (in gusts) for 1-3 hours (at any given location)
in the pre-dawn hours. This will be especially true along the
coast and portions of the coastal plain. Lesser winds will be
found inland (except for the n-nw slopes of the Whites). It`s
possible that much of NH and far interior ME see their strongest
wind gusts from this system Monday afternoon when better mixing
takes place in the wake of the low.
630 PM Update...Very little change to the going forecast. Things
are progressing as planned so far...with rain very gradually
increasing in coverage. Winds are also increasing gradually, and
these should peak between after 2 am. Rain will become heavy at
times mainly after 10 PM in the south and after midnight further
north. Will continue to watch trends in wx obs to the south of
us for any forecast changes, but at this time we are on target.
Previously...
Strong and complicated storm system moving though the region
overnight. From a general perspective, forecast thinking not
much different from previous forecast, and high impacts are
expected both from wind and heavy rain. The two most respected
models, Euro and HRRR are in good agreement on the track of the
secondary sfc low /the one associated with remnants of
Philippe/, taking across Cape Cod, crossing onshore around KPSM
and ending up in the NE Kingdom of VT by Mon morning.
Wind: Core of the low lvl wind should be just to the east of
this low, which would pretty much put across all out coastal
zones and the waters. Jet speeds at 925 mb are forecast to be
around 80 kts, pushing close to 100 kts around 850 mb. Strong
inversion will prevent full momentum transfer but even some
moderate mixing will get some gusts of 40-50 mph to the sfc
over the waters and near the coast. The problem is that this a
very dynamic system, and both convection, and other sources of
strong downward motion could mix a bigger chunk of the winds
down to the surface, and this will be where the 50-60 mph winds
may make it down, although they will be less frequent. Cannot
rule out a few gusts in the 60s as well.
Strongest winds should fall between midnight and 8 am, earlier
in the timeframe in NH, and later in western ME. Further inland,
should see some gusts to 40-50 mph, with some higher winds
above 1500 feet in elevation. Also, the SE wind downslope areas
and notches of the Whites in NH will se some of the stronger
gusts, perhaps to 60 mph.
Rain: Given the strength of the low lvl jet, and the tropical
source of the air, should see impressive upglide over both the
coastal front and the SE upslope areas of the mountains. These
regions will likely see 2-3.5 inches of rain, with locally
higher amounts. Most other spots will see 1.5-2.5" and the bulk
of this precip will fall overnight, so flooding is an issue.
Mostly minor urban and poor drainage flooding will occur, but
could see localized flash flooding as well. Several rivers in
the mountains are forecast to go flood as well, and this is
detailed in the hydro section.
Temps stay close to where they are now overnight, generally a
few degrees either side of 60.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Winds and rain should begin diminish during the morning hours,
with most of the rain ending or tapering showers by midday. So
additional rainfall of impact will likely be limited to early to
mid morning. Again the winds should begin to diminish after
around 12Z or so. However, when the winds shift to WSW will
likely see another surge of winds in the well-mixed atmosphere
of CAA. We will likely need to extend wind products into Mon
afternoon, but the thinking now is that these will be advisories
across the CWA. Should begin to see clearing outside of the
mountains in the afternoon as well. Temps will start off around
60 in the morning, but once the CAA begins, will see temps fall
thru the 50s during the afternoon.
Winds gradually diminish Mon evening, but will probably stay
10-15 mph thru the night. It`ll be colder with lows in the mid
30s to mid 40s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
We remain in a stiff westerly flow on Tuesday between high
pressure to our south and low pressure well to the north in
Canada. Winds will be gradually decreasing, though, but
temperatures will be cool by recent standards, normal by longer
term standards. High pressure moves in from the southwest
Tuesday night, allowing winds to go calm by morning especially
over New Hampshire. There may be some higher level cloud cover
spilling in by morning, though, which would prevent ideal
radiational cooling conditions. Should still see temperatures
drop to near or below freezing in the cold spots. Portland is
still waiting for its first freeze of the season and is already
in second place on the all time list of latest first fall
freezes. If it doesn`t happen Wednesday morning we will likely
set a new record.
High pressure moves east on Wednesday with a southerly flow
returning. This will bring gradually more warmth and moisture
into the region. Models are slowly coming into better agreement
on timing and track of the next wave which will begin affecting
us later in the week. It is looking more and more like this low
will track fairly well to the north of our area, keeping us out
of the heavier precipitation, with the best shot of rain being
on Friday with the cold front moves through. However, there
will be increasing cloud cover as the southeast flow off the
water brings in some low level clouds and perhaps some drizzle
on Thursday. The GFS has a more defined warm front with warm
advection precipitation on Thursday, but it appears to be the
outlier at this point, with other models keeping these dynamics
further to the north.
The front moves through on Friday with colder air moving in for
the weekend. Cold high pressure moves in Saturday night. GFS
brings another weak wave through the area Saturday night with a
chance of rain (and snow to the north). However, CMC and ECMWF
both keep the high over Maine through Sunday morning. Given the
consistency with these models, have discounted the GFS just a
bit and favored the forecast towards the ECMWF/CMC. This would
mean Sunday morning could be a good radiational cooling morning
with a widespread freeze. The cold won`t last too long, though,
as we get back into the southwest flow again early next week.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Short Term...Strong low pressure moves north through the Hudson
River Valley tonight. To the east of the low track, we expect
gradually lowering ceilings and increasing rainfall rates. In
addition, a strong low level jet will develop, with winds of
60KT or more at about 2000 FT overnight tonight, especially over
Maine locations. This will cause low level wind shear, but we
may actually mix down some higher gusts from within this jet.
Gusts to 50KT are possible along the coastline and even a bit
inland from the coast. Southeasterly downsloping winds at
Whitefield may also gust to 50KT at times. The rain will come to
an end early Monday morning along with the lower ceilings, with
the winds shifting to the southwest and diminishing in
intensity. However, as a cold front moves through Monday morning
expect winds to shift to the west and gust to 35 or 40 KT area
wide, gradually diminishing into Monday night.
Long Term...Westerly winds remain fairly strong on Tuesday but
will finally calm down Tuesday night as high pressure moves
through. A return southerly flow begins on Wednesday, with lower
ceilings possibly moving in off the Gulf of Maine as early as
Wednesday night or Thursday. Another cold front moves through
from the northwest on Friday, pushing out the low level moisture
and returning VFR conditions to the region after a brief shot of
rainfall.
&&
.MARINE...
Short Term...Flags will stay as they are with storm force winds
developing this evening, and a period of hurricane force gusts
in the outer waters. Will likely see a short window of a couple
of hours for hurricane force winds shifts from W to E across
the waters during the warning period. Given the strength of the
winds should see seas rise to 18-25 ft early Monday. On Monday
should see storm force winds continue through most of the day,
eventually diminishing to gales Mon night.
Long Term...Westerly winds on Tuesday will gust into the 30 to
35 KT range before diminishing Tuesday night with high pressure
moving by. A southerly flow begins again by Thursday, possibly
reaching advisory levels before the next cold front arrives on
Friday.
&&
.HYDROLOGY...
Flash Flooding:
A very quick hitting storm with deep tropical moisture
connection means that flash flooding is likely across the
foothills and mountains of Western Maine and New Hampshire. Most
of the QPF /around 2-3 inches/ falls in less than 12 hours which
should easily exceed the flash flood guidance across portions
of the region. A flash flood watch remains in effect and flash
flood warnings may be needed overnight.
Rivers: Many rivers are already running a bit high from our last
batch of rain and that combined with now fairly saturated soil
will result in river flooding. The area of greatest QPF is in
the White mountains where some of the fastest reacting rivers
are located. With confidence high for widespread 2-3" amounts
through this area, and the potential for higher amounts river
flood warnings have already been issued for the Pemigewasset
river at Woodstock, the Saco at Conway, and the Swift at
Roxbury. These rivers are expected to reach flood stage by
morning. Anyone with interests along these rivers should take
action tonight before nightfall.
Elsewhere in the Whites, there are several points which may
reach flood stage, but with less confidence in reaching flood
and a later crest time have opted to hold off on warnings at
this point. These points include the Ammonoosuc river at
Bethlehem, the Baker at Rumney, and the Pemi at Plymouth.
Extending into Maine widespread 2-3" amounts are anticipated
into the upper Kennebec basin, including the Sandy and
Carrabassett rivers. These rivers take longer to react and thus
will hold off on flood warnings for now. The mainstem Kennebec
is also heavily regulated and may be able to hold off folding.
Interests along the Kennebec should monitor this storm closely.
&&
.TIDES/COASTAL FLOODING...
Despite a low tide of around 8.5 ft
at Portland, storm surge of 2-2.5 feet is expect, which will
remain below coastal flood levels. However, with high waves and
the surge some splash over and minor beach erosion will be
possible at highs tide around 745 AM Monday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Flash Flood Watch through Monday afternoon for MEZ007>009-
012>014-018>028.
Wind Advisory until 11 AM EDT Monday for MEZ007>009-012>014.
High Wind Warning until 11 AM EDT Monday for MEZ018>028.
NH...Flash Flood Watch through Monday afternoon for NHZ001>015.
Wind Advisory until 11 AM EDT Monday for NHZ004>009-011-015.
High Wind Warning until 11 AM EDT Monday for NHZ010-012>014.
High Wind Warning until 8 AM EDT Monday for NHZ001>003.
MARINE...Storm Warning until noon EDT Monday for ANZ151-153.
Hurricane Force Wind Warning until 8 AM EDT Monday for ANZ150-
152-154.
&&
$$
NEAR TERM...Ekster
SHORT TERM...Cempa
LONG TERM...Kimble
Area Forecast Discussion
National Weather Service Omaha/Valley NE
641 PM CDT Sun Oct 29 2017
.SHORT TERM...(Tonight through Wednesday)
Issued at 335 PM CDT Sun Oct 29 2017
After A Cold Start to the week, warmer Wednesday and Thursday.
Forecast concerns will be small/subtle chances for light
precipitation and temperatures...along with gusty winds Monday.
Warm air advection combined with a weak shortwave quickly moving
from South Dakota into Iowa this morning produced an area of
sprinkles and light rain. Trailing this initial area of rain with
the warm front is a cold front. At midday...the winds had shifted
at KONL and temperatures were in the 60s with 40s and light rain at
Huron. By 3pm...the front had moved into east central Nebraska and
winds were from the north at FET and around 17kts at KOFK.
By 00Z tonight, the cold front should be moving through far
southeast Nebraska and southwest Iowa. Upper level jet support
drops south this evening and into Monday. Ceilings upstream are
generally fl040-100, so high based. Although the short range
models are generally dry, the HRRR/RAP hint at a little more
light precipitation and based on the radar, should see some
sprinkles or light rain behind the cold front. North winds will
pick up behind the front with h9 30-40kts winds. At midday, wind
gusts were mostly 30 to 35kts. Resulting surface winds should be
10-20kts with gusts 25 to 35kts. The Experimental HRRR is a little
more aggressive early this evening toward Fairbury, with gusts
around 40kts...so will need to watch. Will boost winds behind the
front for a couple of hours.
H85 temperatures start out from +2 to +8 at 00Z and drop to -2 to -6
deg C by Monday morning with continued cold air advection as the
closed cyclone over the Great Lakes/trough rotates toward Quebec
brings lowering heights the to Midwest. In addition to the colder
temperatures, strong h85 winds will move into the area. A 35 to
40kt h85 wind max drops south, so this should result in windy
conditions for Monday. Current progs highlight sustained winds in
the 20 to 25kt range with gusts 30 to 35kt, which is below wind
advisory criteria. Monday afternoon, temperatures aloft will be
cold enough for snow, however at this time moisture does not
appear deep enough. Deeper cold air moves in from the north Monday
night and could see some flurries for parts of the area with the
right rear exit region of the jet nearby.
Halloween...a weather shortwave on the backside of the trough
results in UVM and some low level warm air advection in a pocket of
moisture across eastern Nebraska Halloween afternoon and Halloween
night. The models and blends are mainly dry with this feature,
however the EC does have a little light perception in southeast
Nebraska. The snow algorithms for the GFS20/EC/UKMet spit out a
little snow/rain there, although this is washed out in the
blends. For now will mention flurries/sprinkles and continue to
monitor as the system approaches.
After a couple of colder days Monday and Tuesday (highs in the
40s), temperatures should warm into the 50s for Wednesday.
.LONG TERM...(Wednesday night through Sunday)
Issued at 335 PM CDT Sun Oct 29 2017
A cold front move through Wednesday night and Thursday with
surface high pressure building into the Northern Plains. The
coldest air never makes it to the MO Valley as mid level height
rises develop with increasing south for across parts of the
western High Plains. Fairly strong warm air advection aloft least
to a few showers in northeast Nebraska Friday and there may be
some small shower chances Saturday into Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 636 PM CDT Sun Oct 29 2017
Mainly VFR conditions are forecast through Monday evening. Broken
to overcast mid clouds are expected overnight, with one band of
cigs near FL030 that may briefly affect KOMA and KLNK for a hour
or so. Otherwise gusty north wind behind a cold front will average
15 to 25kt for a few hours into the evening before settling back
toward 12kt. Then strong winds are again forecast Monday with
northwest winds 20 to 30kt beginning at 14Z and continuing through
the afternoon.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Dergan
Area Forecast Discussion
National Weather Service Pocatello ID
916 PM MDT Sun Oct 29 2017
.UPDATE...Satellite imagery shows broad area of thin high clouds
spreading across central mountains and northeast corner. Have
nudged Sky grids upwards overnight in response to cloud trends.
Cold front has dropped well into East Idaho per surface obs.
Coldest air remains north of Divide, well evidenced by IR
satellite imagery and sfc obs, but north winds currently slightly
higher than forecast. Have nudged winds upwards slightly,
especially through upper valley and close to Divide were a few
sites gusting well over 30 mph. Strongest winds still expected to
migrate down the Snake Plain through the remainder of the
overnight. If HRRR trends hold true, could see a few locations
across central portions of Snake Plain near Great Rift east of
Shoshone experience winds close to or over Advisory criteria, but
area is limited and timing of strongest winds quite short so will
continue to hold off on any headlines overnight. DMH
&&
.PREV DISCUSSION... /issued 130 PM MDT Sun Oct 29 2017/
SHORT TERM...Tonight through Tuesday Night.
A pair of cold fronts will move through the region tonight. The
initial front is more of a wind shift and will move through late
this afternoon and early this evening. The stronger front arrives
late evening and overnight. The stronger front will produce gusty
winds overnight. Potentially could see wind gusts up to 40 mph
across the Snake Plain. Also temps are much colder behind this
second front. Although we are not expecting precipitation with
this system as the air mass is simply too dry. Expect nippy
conditions for the Monday morning commute as wind chills will be
in the teens across much of the area. Look for highs to be about
15 degrees cooler on Monday with most areas staying in the 40s for
highs. Cool dry weather will hang around through Tuesday. A very
weak system will pass northeast of the region, there`s an outside
shot of some light snow across the Island Park region Tuesday
night, but right now looks more likely that it will remain dry.
Valle
LONG TERM...Wednesday through Sunday...The northwest flow regime
in the upper atmosphere forecast for Wednesday will gradually break
down into a west to southwest regime as an area of low pressure from
the northwest digs along the PacNW coast Thursday. Moisture will
surge into Idaho by this time with snow showers expected over 7000
ft and rain below it. As a cold front approaches our area and
passes through over the weekend, expect an increase in
precipitation. The timing of this feature currently differs
between the global weather solutions. Precip amounts are also
widely varied during the weekend time frame with rather decent
amounts possible, especially in mountainous territory. Look for
cooler temperatures by Sunday and into early the following week.
NP/Valle
AVIATION...The primary weather hazard to be aware of will be very
strong north to northeast winds starting in the overnight hours and
persisting during the day. For KPIH, KIDA and KBYI, sustained winds
of at least 18 knots are forecast with gusts to 30 knots or more.
There is potential for a short period of LLWS prior to the arrival
of these winds as well, with the most confidence in shear at BYI.
DIJ is not showing much indication of much increase in winds at all
per the latest guidance in high resolution models, but this could
change by morning. KSUN should be not see that strong of winds as
well. NP/Valle
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
320 PM MDT Sun Oct 29 2017
.SHORT TERM...(This evening through Monday)
Issued at 320 PM MDT Sun Oct 29 2017
A cold front will move through southeast CO this evening, with winds
becoming north to northeast. The forecast models then show
increasing low level moisture, low clouds and the potential for
areas of fog late tonight, and the sfc winds becoming easterly. The
NAM and the HRRR show light pcpn moving into the Palmer Divide
around 4 am. The GFS is similar. The pcpn then spreads southward
through the morning hours on Mon. Much colder air spreads into the
area for Monday, and temps will be 40 some degrees cooler than today
over the southeast plains. High temps for Mon along the I-25
corridor are expected to occur around midnight, with temps then
cooling. Forecast soundings show the potential for some light
freezing drizzle Monday, mainly along portions of the I-25 corridor
and near the eastern mtns, otherwise light snow is expected. Don`t
feel confident enough that a widespread freezing pcpn event will
occur, so will not issue a weather highlight. However, if
subsequent model runs look more favorable for a widespread freezing
pcpn event, an advisory may be needed. At this time, all models
are showing pcpn chances ending over the far southeast plains during
the afternoon hours, with the best light pcpn chances being mainly
right along the eastern mtns.
Western portions of the forecast area are expected to be only
slightly cooler on Monday. At this time, it appears that the western
mtns and the high valleys should stay dry thru midday Mon. Then in
the afternoon, some light pcpn develops in the afternoon, but
doesn`t look widespread or significant.
.LONG TERM...(Monday night through Sunday)
Issued at 320 PM MDT Sun Oct 29 2017
Monday night through Tuesday...The upper trough axis swings
southeast across the Great Basin and bring snow chances back to all
of the higher terrain, with a focus on the Continental Divide. With
snow increasing along the Divide, and continuing over the e mts,
forecast snowfall amounts pointed towards the issuance of a Winter
Weather Advisory with fairly widespread 4 to 7 inches, and localized
10 to 12 inches, for areas above roughly 10000 feet for the Divide
as well as the Sangres. There should be some patchy higher amounts
for Pikes Peak and the Wets, but did not feel it was widespread
enough to warrant any highlights there. Models are painting a
picture that indicates some upper jet dynamics playing a part, as
the right rear quad of the jet moves across the CWA at about the
same time that snowfall amounts blossom for the Divide and the
Northern Sangres. Where this actually sets up is of course fluid at
this point. Pcpn will begin to taper off Tue aftn across the e
plains, then for all areas through Tue evening. Look for a very cold
night across the region Monday night with min temps in the teens and
20s, then warming into the 40s to around 50F for Tue.
Wednesday and Thursday...Dry conditions with gradual warming as the
upper trough moves out, and northwest to westerly flow aloft settles
in. Expect max temps in the 50s to lower 60s for the high valleys,
and mid 60s to lower 70s for the plains.
Friday through Sunday...Long range models show the upper flow
strengthening and becoming more southwesterly into the weekend, as a
strong upper low pressure system rotates over the Pacific NW. Expect
isolated snow along the Continental Divide and especially the
central mts over the weekend. Temps will warm into the upper 50s to
around 60F for the high valleys, and 60s to lower 70s for the
eastern plains. Moore
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 320 PM MDT Sun Oct 29 2017
VFR conditions are expected at KALS thru the next 24 hrs, with winds
generally under 10 kts until about midafternoon Mon, at which time
southerly winds are expected to increase.
KCOS should have VFR conditions through the evening hours, but then
later tonight the ceilings will lower into the MVFR category and
will likely be IFR by about 12Z Mon and should remain that way thru
the day. Freezing drizzle or light snow will be possible on Mon.
KPUB should have VFR conditions through at least midnight. Late
tonight the ceilings will lower into the MVFR category, probably by
10Z. MVFR conditions are then expected thru 00Z. There will be the
potential for light precipitation Mon, including freezing drizzle
and snow, and there could be periods of IFR conditions.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 9 PM Monday to 6 PM MDT Tuesday for
COZ060-066-068-073-075.
&&
$$
SHORT TERM...28
LONG TERM...MOORE
AVIATION...28
Area Forecast Discussion
National Weather Service Blacksburg VA
829 PM EDT Sun Oct 29 2017
.SYNOPSIS...
Low pressure will deepen off the North Carolina coast this
evening and track north into New York by morning. High pressure
will cover the southeast United States tonight through Monday
night. A front will move into the area on Tuesday then move north
of the region by Thursday.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 815 PM EDT Sunday...
Minor updates to account for negative tilt shortwave trof
enhancing upslope show showers with flurries extending out the
Blue Ridge. Winds have been gusting 40MPH to 50MPH and guidance
supports continuation robust winds into Monday morning, so no
changes needed to the current advisory.
Previous discussion...
Upper low along the Tennessee/Georgia border as seen on water vapor
loops will shortly close off then race northeast tonight, reaching
eastern Pennsylvania by morning. Left wide broad ribbon zonal flow
over the region on Monday. Much of the synoptic scale forcing
moves northeast out of the area by early morning.
Low level jet from the northwest increases today and brings the
850MB winds up to around 50 knots along the Blue Ridge tonight.
At the surface low pressure over eastern North Carolina moves
northeast and rapidly deepens, increasing the pressure gradient
over Virginia, West Virginia, and North Carolina. No change
needed to the Wind Advisory at this time.
Models similar in timing of the western edge of the showers tonight
and the erosion on the upslope clouds in the west on Monday morning.
SPC HRRR and other short range guidance has precipitation east of
Buckingham and Charlotte Counties by midnight. Less of a pressure
gradient on Monday and winds turn more to the west which will also
aide to eliminate upslope clouds.
Temperatures and dew points had dropped into the 50s in the Virginia
and North Carolina piedmont behind the front. Will have mildest lows
tonight in the east where clouds will take the longest to clear. In
the foothills that were already seeing breaks in the clouds and have
surface dew points in the 30s, temperatures should have more of a
drop. 850mb temperatures begin to moderate on Monday and there will
be primarily sunshine for a large part of the area. Will stay
close to National Blend and MAV for maximum temperatures.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 230 PM EDT Sunday...
Synoptic flow across the area will continue to back to more of a
westerly component with zonal flow establishing itself across the
region. The broad upper low over Quebec will make a slow progression
northeast through this portion of the forecast with its associated
moisture and dynamics remaining north of the area. Surface high
pressure will build overhead by Tuesday morning. Anticipate dry
conditions with temperatures trending cooler.
By Tuesday night into Wednesday, the flow aloft continues to back,
becoming southwest with a warm front developing east of a shortwave
trough heading eastward through the Arklatex region. The result will
be increasing cloud cover overnight, temperatures and dew points
with patchy light rain developing along the warm front. Coverage
across our region will be confined to primarily the northwestern
sections on Wednesday. Temperatures will trend milder Wednesday and
Wednesday night as compared to 24 hour prior.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 1230 PM EDT Sunday...
A warm front will lift north of the area Wednesday night in response
to the approach an upper level trough moving east of the Mississippi
River Valley. The associated baroclinic zone with this trough is
progged to lag behind the eastward progression of the parent upper
low over Ontario/Quebec. The result will be a frontal boundary that
stalls near the Ohio River Valley into parts of the Tennessee Valley
heading into the weekend.
Not until the next upcoming weekend does the guidance look promising
to bring a shortwave trough move through the Great Lakes region to
eject this front eastward into and through our area.
The result is expected to be some patchy light rain across the
northwest section of the region Thursday and Thursday night, nearest
the location of the warm front. Look for increasing chances of
showers as we head into and through the weekend. Convective
parameters hint at the potential for some isolated thunderstorms
Friday afternoon in areas along and near the Blue Ridge, Saturday
afternoon across part of the Mountain Empire region of southwest
Virginia and Northern Mountains of North Carolina, and with
potential across the entire forecast area Sunday afternoon.
Temperatures during this portion of the forecast will trend milder
to readings some ten degrees above normal by Friday, then cool to
values about five degrees above normal on average by Sunday.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 810 PM EDT Sunday...
Low pressure will deepen rapidly as it moves up the middle
Atlantic coast and into New England tonight. This will allow
northwest winds on the backside of the low to strengthen and
bring very gusty conditions to TAF sites through daybreak. Gusts
of 30kt to 40kt can be expected at most sites, but stabilization
and stratification in the boundary layer may create periods of
slacker winds with no gusts as the night wears on. Will choose
to focus on the more impactful higher gusts with no mention of a
lull. The low level flow will gradually diminish Monday morning
and allow gusts to slowly subside though the end of the TAF
period.
The northwest flow is also causing upslope snow and MVFR/IFR
cigs/vsbys west of the Blue Ridge. Expect this will be the case
most of tonight before moisture starts to wane as we get closer
to daybreak, when conditions begin to improve. Expect VFR all
sites by mid morning Monday through the end of the valid period.
Extended Discussion.... Wind gusts will slacken and continue to
diminish Monday evening. High pressure over the southeast
United States will provide VFR conditions through Tuesday.
By Thursday, another cold front will be just west of the area,
so the potential for showers and sub-VFR conditions will
increase again, especially in the west.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Wind Advisory until 11 AM EDT Monday for VAZ009>020-022>024-
032>035.
NC...Wind Advisory until 11 AM EDT Monday for NCZ001>003-018-019.
WV...None.
&&
$$
SYNOPSIS...AMS
NEAR TERM...MBS/AMS
SHORT TERM...DS
LONG TERM...DS
AVIATION...MBS/AMS