Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/12/19
Area Forecast Discussion...Updated
National Weather Service Billings MT
834 PM MST Wed Dec 11 2019
Light snow showers continued over eastern areas this evening as a
shortwave tracked east into the Dakotas. Snow will gradually
diminish through the remainder of the evening over the plains.
Patchy fog is possible from Miles City to Baker late tonight and
tomorrow morning. At the same time, snow will increase over the
southwest mountains tonight as a plume of Pacific moisture works
into the region. The Winter Storm Warning for the
Beartooth/Absaroka mountains in effect from midnight tonight
remains on track. Have adjusted temperatures, pops, and sky cover
to reflect latest trends and observations. The rest of the
forecast looks to be in good shape and the previous discussion
and an updated aviation discussion are below. STP
Tonight through Thursday Night...
Satellite imagery shows a shortwave moving through central
Montana, an area of drier air over the northern Rockies (just
upstream of our area), and a moist westerly flow spreading into
the PacNW. At the surface, lee side surface low remains but there
are pressure rises noted along the MT/Canada border. Winds have
been decreasing at Livingston and have cancelled the wind advisory
for the Livingston area and Beartooth Foothills. Winds at these
locations will remain elevated tonight through Thursday night,
with some gap enhancement again tomorrow, but currently we expect
gusts to remain at 50 mph or less. A heads up for travelers on
Moist Pacific flow will bring a period of accumulating snowfall to
west aspects of the Beartooth Absarokas late tonight thru Friday.
This appears to be a typical heavy snow set-up for the mountains
around Cooke City with convergent mid level winds, and a deep
moisture fetch extending west to near the dateline. Have upgraded
the Watch to a Winter Storm Warning for 12-18" of snow from
midnight tonight through Friday. By Friday, jet energy and deeper
moisture will sag to our south. Heaviest snow should occur on
Shortwave currently in central Montana will bring some light
precip to our eastern cwa between now and 03z. There was a concern
that some precip could be in the form of light freezing rain,
with an elevated warm layer on top of cold valleys, but spotter
reports, web cameras and local observations all support the precip
being just snow. Once this exits to our east, we will see another
weak backdoor front slide into our east bringing another
reinforcement of colder air and quite possibly some low stratus.
HRRR is suggestive of fog late tonight and while it may turn out
to be just low cloud, have added patchy fog to Miles City and
Baker after 06z tonight.
Next Pacific shortwave on Thursday may produce some very light
showers at our lower elevations, but downsloping will keep things
mainly dry. Subsidence behind this wave will push stronger west
winds to Big Timber and Harlowton tomorrow afternoon, with gusts
near 50 mph possible. By late Thursday night, we may begin to see
the effects of the next Canadian fropa, a stronger one which
could produce some snow at lower elevations on Friday.
Temperatures over the next 36 hours will continue to moderate.
Look for widespread 40s on Thursday, with the exception of
lingering 30s in the cooler air in our far east.
Friday through Wednesday...
Unsettled pattern persists through the first half of the extended
forecast period. Elevated winds will also continue to be a
concern in the Livingston/Nye Friday, and again at the beginning
of next week.
A backdoor front will slide into the region late Friday, bringing
cooler temps and a chance for snow to our CWA. The high temp of
the day is expected to occur early in the day, decreasing
throughout the rest of the day behind the front. Heaviest precip
is expected mainly over the central zones to just west of Billings.
At this time, the front does not appear to reach foothills,
before beginning to recede. That said, would not be surprised if
this changes, so have kept lower PoPs in place in foothill and
further west. Uncertainty does remain relatively high, based on
expectations of developing snow band, which could be stationary at
times. Current models keep band moving, but do favor a period of
heavier precip over central zones for a time, as front moves in
Friday, and recedes late Friday night. Front sliding east Saturday
necessitated most significant change, which was to add and
increase pops for eastern zones Saturday. Also lingered PoPs over
the east into Sunday morning.
Winds will remain gusty near Livingston/Big Timber area early
Friday, before decreasing as the front moves in later in the
afternoon. Winds are expected to pick back up again as front
recedes Sunday. Models point to another period of strong and gusty
winds in this area to start the work week, but specific remain a
bit uncertain. Have kept at subadvisory levels at this time.
High temps Friday will vary significantly with FROPA, but should
generally see mid 20s east to upper 30s west. Temps in the 30s
will continue for the western and central portion of the CWA
through early next week, while areas along the ND border will
remain in the teens and 20s.
Scattered light snow showers will produce local MVFR east of KBIL
though the evening. After the precip ends, a combination of low
clouds and fog is expected to produce MVFR or lower conditions
near KMLS and KBHK late tonight into Thursday morning. To the
west, VFR will prevail over the next 24 hours, w/ westerly winds.
Expect gusts of 30-45 kts at KLVM. A moist Pacific flow will bring
snowfall and obscured tops to the Beartooth Absarokas late
tonight through tomorrow. JKL
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
BIL 028/046 031/039 021/034 019/033 019/035 020/038 021/037
01/B 34/O 53/S 21/B 11/B 10/B 11/B
LVM 032/046 031/038 022/032 017/029 018/032 020/036 021/035
15/W 45/O 42/S 21/N 12/S 20/N 11/N
HDN 021/046 025/038 015/033 014/032 013/032 015/038 017/036
21/B 35/O 53/S 21/E 11/B 10/B 11/B
MLS 016/039 022/028 010/022 012/028 013/030 017/035 015/032
22/W 24/S 23/S 21/E 00/B 11/B 11/B
4BQ 018/041 024/036 012/029 013/028 013/030 015/035 016/035
21/B 24/O 22/S 22/S 00/B 10/B 00/B
BHK 010/037 018/025 002/018 007/025 010/025 012/031 012/029
30/E 12/S 12/S 22/S 00/B 11/B 01/B
SHR 019/045 023/038 014/032 011/030 010/032 012/038 016/039
01/B 34/O 42/S 22/S 11/B 11/B 00/B
MT...Winter Storm Warning in effect from midnight tonight to 5 PM
MST Friday FOR ZONE 67.
Area Forecast Discussion
National Weather Service Caribou ME
1003 PM EST Wed Dec 11 2019
An Arctic cold front will cross the region tonight. Cold
Canadian high pressure will build over the region Thursday. A
warm front will lift north of the area Friday. Low pressure will
lift north across Maine Saturday. A cold front will cross the
region Sunday. High pressure will build toward the region later
.NEAR TERM /THROUGH THURSDAY/...
10 PM Update...
Adjustments were made to the precip coverage w/a band of light
snow associated w/a a pre-frontal trof was pushing east. The
latest radar showed light returns moving east across northern
and central Aroostook County. Mesoanalysis showed some
convergence w/this band. Therefore, decided to bring snow
showers in a bit earlier and further to the east. Obs showed
some warming indicative of weak WAA aloft w/the boundary.
K40B(Clayton Lake) rose to 16 degs the last hr. Tweaked the hrly
temps to take this warming into accounts. The cold front that
is expected to move through by early Thursday morning was still
back across the Maine-Quebec border. Regional radar showed a
line of enhanced reflectivity w/the front. Some of the dynamical
parameters from the HREF, RAP and NAM12 point to the potential
of a few snow squalls later tonight moving across western and
then into northern areas. The previous forecast looks to have
this handled well and little adjustment was needed.
The cold air advection and bitterly cold northwest winds will
be the primary byproducts of the front for later tonight into
Thursday. The only precipitation will be a brief snowshower with
fropa, mostly in Aroostook County. Lapse rates steepen briefly
with the front, but the front moves so quickly that
accumulations more than a half-inch in a squall seem unlikely.
The snow squall parameter does flash a signal after midnight in
northern Aroostook County with those steeper lapse rates and
potential gusts to 40 mph. Thus visibility in a squall could
briefly go to zero for pre-dawn travelers in that region. The
air is so cold that St Lawrence moisture may continue to provide
flurries in the Saint John Valley well into Thursday morning.
Highs on Thursday will only reach the low teens in northern
Aroostook County and no more than the lower 20s towards Bangor
and the coast. More notable will be subzero wind chills through
the day in the northern half of the forecast area, and just
single digits in the southern half of the forecast area. Winds
will start to decrease during the afternoon as the high builds
and radiational cooling will get off to a quick start after
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
High pressure begins to exit across the Maritimes Thursday
night, with a developing warm front across the region. Clouds
will increase across the forecast area Thursday night, with a
chance of snow showers across northern areas in the vicinity of
the developing warm front. The warm front lifts north Friday.
Expect mostly cloudy skies across the region Friday with a
slight chance of snow or snow showers. The warm front moves
north of the region Friday night, with developing low pressure
across the Mid-Atlantic region. Expect rising temperatures
Friday night with warm advection. Moisture also begins to
expand north in advance of the Mid-Atlantic low with increasing
precipitation chances. Across Downeast areas, expect a rain/snow
mix early Friday night which will transition to rain overnight.
Snow will transition to a snow/rain mix across central portions
of the forecast area, with mostly snow across northern areas.
The intensifying low lifts north across New England Saturday.
Precipitation will remain in the form of rain Downeast Saturday.
Snow will transition to rain across the remainder of the region
through Saturday morning into the afternoon. Total snow
accumulations through early Saturday, before the transition to
rain, will generally range from 1 to 3 inches across the north
and mountains with the greater totals across the Saint John
Valley and higher terrain areas. Snow totals diminish southward
across the forecast area with less than an inch expected across
Downeast areas. Temperatures will be at near normal levels
Friday, warming to above normal levels Saturday.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The low will lift across Maine Saturday night, reaching northern
Maine late. Rain will persist Saturday night with near steady
temperatures. The low will lift across the Gulf of Saint
Lawrence toward Labrador Sunday. The low will draw a cold front
across the region Sunday morning into the afternoon, though the
exact timing is still uncertain. The heavier precipitation will
exit across the Maritimes in advance of the cold front.
Precipitation will remain in the form of rain in advance of the
cold front, then transition to snow or snow showers following
the cold front. Gusty southwest/west winds will develop
following the cold front then persist into Monday. Snow showers
could also linger across the north and mountains Sunday night
into early Monday with partly cloudy/mostly clear skies
Downeast. High pressure will build across the region Monday with
decreasing winds along with partly cloudy/mostly clear skies.
Low pressure should affect the region Tuesday. However, the
track of the low remains uncertain. Precipitation types/amounts
will be dependent on the eventual track. The low should exit
across the Maritimes Wednesday. Generally expect partly/mostly
cloudy skies Wednesday, with a chance of snow showers.
Temperatures will be at above normal levels in advance of the
cold front Sunday. Below normal level temperatures are expected
Monday through Wednesday.
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR conditions are expected outside snow showers
with the cold front, mostly at FVE. These snow showers could
provide tempo IFR vis. Low level wind shear is possible at
sites north of BHB later tonight into early Thursday morning.
Thursday night...VFR early. MVFR/IFR conditions developing
overnight. A chance of snow showers across northern areas.
Friday...VFR/MVFR. A slight chance of light snow or snow
Friday night...Conditions lowering to IFR/LIFR levels with snow
north, a snow/rain mix across central areas and snow changing
to rain Downeast.
Saturday...IFR/LIFR. Snow or a wintry mix transitioning to
rain north, with rain Downeast.
Sunday...IFR/LIFR early. MVFR/IFR during the afternoon, then
VFR/MVFR late. Rain early. Precipitation transitioning to snow
or snow showers following a cold front. Gusty southwest/west
winds following the cold front.
Monday...VFR/MVFR early, then VFR. A chance of snow showers
early across the north and mountains. Gusty west winds.
NEAR TERM: Continue to anticipate a quick hitting gale later
tonight into early Thursday morning. SCA conditions will follow
the gale into later Thursday afternoon.
SHORT TERM: Conditions below small craft advisory levels
Thursday night. Small craft advisory conditions Friday through
Saturday, with gusts possibly approaching gale levels later
Saturday. Visibilities reduced in rain Friday night through
MARINE...Small Craft Advisory until 9 AM EST Thursday for ANZ052.
Gale Warning until 9 AM EST Thursday for ANZ050-051.
Area Forecast Discussion
National Weather Service Cleveland OH
929 PM EST Wed Dec 11 2019
A ridge of high pressure over the region this morning will get
pushed south as a cold front moves through the eastern Great
Lakes this afternoon. Behind the front, high pressure will
reassert itself over the Ohio Valley for Thursday before moving
off the East Coast for Friday. A pair of low pressure systems
will then surround the region for the weekend, as a low moves
through the northwest Great Lakes, eventually merging with a
stronger low moves up the East Coast.
.NEAR TERM /THROUGH THURSDAY NIGHT/...
A westerly low-level flow of cold air should continue directing
bands of light lake effect snow in/near the snowbelt of
northeast OH and northwest PA before these snow bands dissipate
by the predawn hours of Thursday morning. As high pressure at
the surface and aloft builds from the west, decreasing low-level
moisture, a lowering subsidence inversion, and decreasing lake-
induced instability will lead to the eventual demise of this
lake effect snow.
Outside the lake effect snow, light snow showers are also moving
eastward across interior portions of north-central and
northeast OH. Latest RAP data suggest these snow showers are
associated with lift along and ahead of a subtle shortwave
trough axis. As the shortwave trough axis continues moving
eastward, these snow showers are expected to end from west to
east through 10 PM this evening. Any additional snow
accumulations here in our CWA will likely be less than an inch.
Over and near the snowbelt, skies are expected to remain partly
to mostly cloudy through Thursday morning. Lake effect cloud cover
over and near the snowbelt should finally exit the area around
and especially after daybreak as the low-level flow backs from
westerly to southwesterly. However, mid- to upper-level cloud
cover associated with isentropic lift should eventually
overspread our entire CWA from west to east Thursday morning.
Used NBM guidance to update our sky cover forecast to better
match observed and expected trends. Also decreased Thursday
morning low temperatures by a few degrees for locations outside
the snowbelt. 10th percentile low temperature values from all
available model guidance were used for this adjustment. Outside
of the snowbelt, mainly clear skies, light surface winds, and
limited low-level humidity should permit efficient radiational
cooling before the aforementioned west-to-east increase in cloud
cover. The rest of our near-term forecast remains valid.
PREVIOUS DISCUSSION...Heavy lake effect snow over Lake Erie has
moved onshore over the past hour or so with winds gusting up to
40 mph. Heavy snow and gusty winds will produce blowing snow
and visibilities down to 1/4 mile or less at times. Snow
observed elsewhere, near places such as Youngstown, Akron,
Canton, and Mansfield is associated with a shortwave trough at
700 mb, which is producing more moisture advection and forcing
than predicted by model guidance. Around half an inch or less is
expected out of this snow, just enough to put a coating down.
Heavy snow is expected to persist through the next few hours
especially for Lake, northern Ashtabula and northern Erie. Snow
is expected do diminish tonight as moisture decreases as
moisture associated with the upper level trough exits the area
to our east. Total snow expected through this evening and
tonight will be highest across the northeastern part of Erie
County, where 3 to 5 inches of snow is expected. Other areas
such as Lake, northern Ashtabula, and northern Crawford can
expect 1 to 3 inches of snow through tonight.
Sustained west winds of 10 to 15 knots with gusts up to 25 to
30 knots will diminish through the evening and tonight as high
pressure builds into the area. Temperatures are expected to
decrease to the teens tonight and with elevated winds continuing
into the evening and early tonight, wind chills could drops
into the single digits.
High pressure is expected to move the mid-Atlantic by midday
Thursday, with southerly winds developing over the CWA by early
afternoon Thursday. This should warm temperatures back to the
mid to upper 30s by Thursday afternoon. A weak warm front moves
north across the area on Thursday night keeping it from cooling
down too much Thursday night. No precipitation is expected on
Thursday or Thursday night.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The short term begins Friday with low pressure moving east across
the lakes as broad high pressure moves east from New England. Over
the next 24 hours the low will dissipate as another low develops
through the Central Plains. To our east a coastal low will also
begin developing along the Mid Atlantic coast. Between these two
systems, moisture will begin to increase out of the south late
Friday and Friday night affecting the southern and eastern counties.
Saturday, the coastal low will continue rapidly deepening as it
moves northeast along the New England coast. The low to our west
will be absorbed into the coastal circulation with increased
moisture and colder air eventually being wrapped into the back side
of the low and across the area Saturday night into Sunday. Will
have chance pops into the area Friday night for much of the area as
the moisture surges north. For now will have the precip type as rain
with a possible mix far northwest towards morning as pops increase
to likely east. Saturday will continue with likely pops most areas.
Saturday night the precip will begin to mix with then change to snow
from the west as cooler air moves in. Pops will be focused more
across northeast OH and nwrn PA through the overnight. Drier air
will move in from the west for Sunday drying out much of the area
while lake effect snow persists across northeast OH and nwrn PA.
Highs Friday and Saturday in the 40s. Highs Sunday low to mid
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
The main weather maker for the long term will be low pressure
developing out of Texas Monday and moving northeast across the Ohio
Valley Monday night and Tuesday. For some, this will be a snow maker
and others rain into snow on the back side. At this time, the ECMWF
track takes the main low to the New Jersey coast by Tuesday morning
while a weak reflection reaching the Pittsburgh area before
dissipating. The GFS takes the low across the central lakeshore
Tuesday 06z with warm air surging north into the area ahead of the
low. At this time, the system is too far out to really nail down
details but will have likely pops in place for the event and a mix
of precip. Will likely have lake effect develop on the back side of
the system Wednesday with 850mb temps dropping to -14 to -18C
depending on model but high pressure and dry air will also be
building in for again, will not hit too hard. Highs Monday and
Tuesday in the mid and upper 30s. Highs Wednesday upper 20s to lower
.AVIATION /00Z Thursday THROUGH Monday/...
Mainly VFR expected next 24-hours. A subtle disturbance aloft
will exit our region to the east by 03Z/Thurs, while high
pressure at the surface and aloft will build eastward over our
CWA through about 18Z/Thurs. Thereafter, a trough at the surface
and aloft should begin overspreading the area from the west as
the high pressure ridge moves farther east. Lingering bands of
light lake effect snow over northeast OH and northwest PA should
end between 06Z and 09Z/Thurs, while light snow showers over
interior north-central and northeast OH should end from west to
east by 03Z/Thurs. Periods of MVFR ceilings and visibility may
accompany the snow. Breezy westerly surface winds will become
light and variable this evening. Surface winds should then
become southerly and breezy around and especially after
.OUTLOOK...Non-VFR possible Friday afternoon through Sunday
with rain/snow each night and all rain during the daytime hours.
Non-VFR possible with snow and/or rain on Monday.
Will continue with headlines unchanged. Water level will begin
rising between 4 and 6 pm but at 3pm was still close to the critical
mark. Gales not showing up in shorline obs but HRRR 10m winds
suggest 30-35 knots sustained over the water through 00Z before
dropping off. Expect a small craft advisory to replace the gale.
Winds by morning Thursday should turn out of the south at 10 knots
or less but increase through the day to around 20 knots in the open
waters and points north. Waves will be highest along the north
shore. At this time am not anticipating a small craft advisory my
may be close northern reaches of the nearshore waters. Winds will
remain fairly light from much of friday through saturday. The next
chance of small craft headlines will come Saturday night as winds
increase out of the wnw behind deep low pressure in northern New
England. Expect winds will reach 20 to 25 knots Saturday night and
Sunday. Winds and waves will drop back for Sunday night and
MARINE...Small Craft Advisory until 4 AM EST Thursday for LEZ142>149.
Area Forecast Discussion
National Weather Service Gray ME
941 PM EST Wed Dec 11 2019
Arctic air mass will drop south through the region tonight with
snow showers in the mountains and windy conditions. High
pressure will build in and then cross the region on Thursday.
Low pressure will track up the East Coast over western New
England Friday night through Saturday night bringing mainly
rain, possibly heavy rain to the area. Precipitation may briefly
start as a wintry mix before quickly changing to rain except in
the mountains where the highest elevations may see prolonged
wintry precipitation before changing over. Windy and colder
conditions follow Sunday into Monday. Another colder system will
approach New England Monday night into Tuesday that may bring
more wintry precipitation.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
940 PM...The line of SHSN with embedded squalls moving through
nrn NH and NW corner of ME attm. holding together fairly well,
but HRRR starts to weaken after 03Z, so will go with this idea
as it moves away from best forcing and weakening lapse rates.
Have increased the POPs in the grids further to the S and E
thru about 05Z though.
645 PM...Main issue this evening will be snow showers and
potential squalls over the far nrn zones, as second surge of
cold air moves in with wave aloft. Pretty good band coming
across nrn half of Lk Champlain attm, with secondary bands in
the Adirondacks and Mohawk vly of NY. These bands are currently
being enhanced by Lk Effect off Ontario, and will likely loose
some of their punch as they work way into the nrn half of NH.
Still the nrn part of the band may hold together better given
it`s proximity to best forcing aloft, and so areas N of the
White mtns in NH and N and E of Rangeley and Jackman in ME are
where the best chc for a squall exists this evening. Otherwise
in and around the Whites and into the Mahoosucs some sct SHSN
are expected. Temps should hold where they are until the front
goes thru later this evening, and then drop quickly, with lows
from 5-10 above in the mtns and in the teens to the south.
As the cold air moves in overnight snow squalls are possible in
the mountains. Snow squall parameter continues to highlight the
Canadian border from 00-03Z time frame. Further, forecast
soundings support this with a shallow saturated layer right in
the snow growth zone and steep low level lapse rates. Brief
periods of heavy snow with wind gusts to 35mph are possible as
this moves through. Have increased the Pops along the Canadian
border as well as the Snow amounts for this time period and will
issue an SPS to highlight the potential.
As cold air moves in overnight expect windy conditions to keep
the lower levels well mixed and thus while temps aloft fall to
around -17C at 850mb, the mixed will keep the temperatures
above zero across the north. Have still leaned a bit on the
colder side of guidance as after the initial cold push this
evening some calming of the winds may occur in sheltered valleys
early tomorrow morning.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
High pressure will build in for Thursday with winds steadily
decreasing as the high crests over the region for Thursday
afternoon. Stuck with a consensus for the temperatures for what
should be a nice day. Thursday night had been looking like the
coldest night of the week as the high passes to our east but
some mid level clouds may prevent the radiational cooling from
taking hold in the north and so have not gone quite as bullish
on the cold as past forecasts. Still temperatures will remain in
the single digits overnight.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
High pressure will be well east of the area Friday morning with
return flow advecting warmer air into the region. Highs on
Friday will run 10 to 15 degrees warmer than Thursday with
mostly cloudy skies.
The next system of consequence will be an area of low pressure
that develops over the southeast US Friday. Deterministic and
ensemble solutions have come in better agreement with a westward
track of this system cutting up into the St. Lawrence Valley.
With milder air already moving into the region ahead of this
system and a westward track, this system is looking to be a
mostly rain event. Precipitation will break out from SW to NE
and may briefly start as a wintry mix before quickly changing
over to rain south of the mountains. In the mountains
precipitation will start as snow changing to a wintry mix before
changing to rain Saturday morning except for the highest
elevations where snow will last the longest. There are some
model differences with regards to QPF with the GFS trending
drier while the ECMWF and CMC suggest upwards of 2 inches are
possible. High PWATS and good orographic flow have led towards
the wetter solutions with 1 to 2 inches of QPF along and south
of the mountains. See the hydrology section for information
about river flooding.
The system moves northeast Sunday with upslope snow showers in
the mountains. High pressure builds into the region Monday
followed by low pressure tracking from the Ohio Valley towards
New England Tuesday. This system looks colder with a track
closer to the coast or just offshore.
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term... VFR will prevail through the next 36 hours.
Another push of cold air moves in tonight and as it does some
snow squalls are possible in the mountains with brief reductions
to visibility for HIE through to Jackman. NWly flow will
continue through evening with VFR and calm conditions for
Long Term...Low pressure will track over western New England
bringing widespread rain to the area Friday night into Saturday
night with MVFR likely. Conditions will improve to IFR Sunday
Short Term...A secondary cold front pushes through off shore
tonight with increasing NWly wind gusting across the waters.
Gales will remain in place and have actually increased
wind speeds above the median as the low level profiles of cold
air over the (relatively) warmer water should help support
mixing down of the higher wind speeds from aloft.
Long Term...Low pressure tracking up the East Coast over western
New England will bring possible gales and elevated seas Saturday
morning into Monday.
Low pressure tracking up the East Coast will bring 1 to 2 inches of
rain to the region Friday night into Saturday night. Recent rain
and mild temperatures have lead to many rivers in New Hampshire to
be running high into the 90th percentile for this time of year.
While much of the snowpack south of the mountains has been decimated
from recent warmth, NOHRSC estimates show that a ripened snowpack
remains from the New Hampshire Lakes Region southwestward towards
the border with MA and VT. This snow pack, although heavily reduced
will likely melt off with this system and along with rainfall
will lead to flooding concerns for rivers in central and
southern New Hampshire. Farther north, into the White Mountains
a rain on snow scenario will likely serve to moisten the
snowpack leading to less runoff and flooding concerns.
Low pressure tracking to the west of the area Friday night
through Saturday night will bring strong onshore flow and
increasing near shore waves. Peak surge with this system is
forecast to occur a few hours after the mid-day high tide
Saturday and this with near shore waves around 5 to 7 feet may
pose some beach erosion and minor coastal flooding concerns.
MARINE...Small Craft Advisory until 7 AM EST Thursday for ANZ151-153.
Gale Warning until 7 AM EST Thursday for ANZ150-152-154.
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
916 PM EST Wed Dec 11 2019
High pressure will build south from the Great Lakes through Friday.
Another cold front will cross the area Friday night and move
offshore early Saturday. High pressure will then build over the
region Sunday into Monday of next week. Another front will impact
the area early next week.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 915 PM Wednesday...No changes to previous thinking.
Strong high pressure centered north of the area will ridge south
producing dry weather across NC through Thu. A canopy of
widespread Cirrus clouds remains across the area this evening.
These clouds are forecast to shift east of the area after
midnight resulting in skies becoming mostly clear overnight. As
the chilly airmass settles over the region, lows tonight will
range from the upper 20s well inland to the mid 30s Crystal
Coast and around 40 Outer Banks. Gusty north winds will persist
near the coast, but will diminish inland.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 310 PM Wednesday...Strong high pressure will pass by our
region to the north during the day Thursday. Despite plenty of
sunshine, low-level thickness values only support high
temperatures that are similar to just a few degrees warmer than
today, with mid/upper 40s inland and low/mid 50s along the
immediate coast. Moderate winds continue inland during the day
Thursday with gusty winds near the coast. Per latest high-
resolution guidance, a stray shower or two may skirt the Outer
Banks later in the day.
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 310 PM Wed...Periods of unsettled weather expected
through the long term period, with roller coaster temps as a
progressive/amplified active weather pattern is expected to
Thursday night...Thursday night will exhibit a non-diurnal temp
curve, with lows likely being realized before midnight,
thereafter clouds and increasing TD`s ahead of next system will
bring temps up towards daybreak, esp near the coast. There may
even be a stray shower that brushes the OBX zones late overnight
Friday through Saturday...Rain chances inc Fri as deep srly
flow increases with digging long wave trough across the lower MS
River Valley, which will spur low pressure development over the
deep south. This low will ride up the coast rapidly, with rain
becoming likely through the day Fri, peaking Fri evening when
best UVV/Fgen/PWATS will converge. Maintained the categorical
pops this period, as good model to model consistency as well as
spaghetti ensembles converging on this solution. Widespread
moderate to heavy rain will be possible. Depending on exact
track of the low, there could be potential for strong to even
severe storms if storm track is further inland. Latest 11/00Z
ECM continues to indicate aoa 500 J/KG of sfc based capes
advecting into the area with plentiful shear overnight Friday.
Upr trough will still be west of the region though deepest
moisture will be offshore Sat morning. Could be quite a bit of
showers around first half of Sat due to good forcing with upr
trough, and have a likely pop for most of the area early, with
rapid drying later in the day. It will be mild both days with
highs in the 60s.
Sunday through Monday...Drier conditions with near to above normal
temps expected late weekend to early next week as quasi zonal
Tuesday...Next potent cold front and possible low pressure
system quickly advance towards the region by Mon night or Tue,
and introduced high chc pops to account for this. Continued warm
as swrly flow ahead of the system will be present.
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term /through Thursday/...
As of 550 PM Wednesday...High confidence in VFR conditions
through the TAF period. Strong high pressure will ridge south
into NC through Thu producing dry weather across the area. The
low clouds have dissipated with widespread high clouds
continuing over the region this evening. These clouds will shift
east after midnight with SKC then expected through much of Thu.
Some clouds will approach from the east late Thu, but any
ceilings should be VFR. Though winds have diminished, good CAA
will result in enough low level mixing to preclude any fog
Long Term /Thursday Night through Monday/...
As of 310 PM Wed...Some increase in clouds on Thurs night ahead
of next system. The low pressure area will quickly advance in
on Friday, with sub VFR expected possibly into Sat morning with
widespread rain showers and low clouds. Return to VFR later Sat
Short Term /Tonight and Thursday/...
As of 915 PM Wednesday...Gusty N/NNE winds continue on the
coastal waters early this evening with a few gusts around 25 kt.
Seas continue in the 4-7 foot range. Winds on the Sounds are
currently 10-20 knots, but should ramp up after midnight as
latest 3km NAM and HRRR show another CAA surge developing and
persisting through early afternoon Thursday. Issued a SCA
earlier for the Pamlico, Albemarle, Roanoke and Croatan Sounds
and the Alligator River for the late tonight through Thursday
afternoon period. There may be somewhat of a lull in the winds
over the northern coastal waters this evening as well, before
ramping up again after midnight in the aforementioned surge.
Long Term /Thu Night through Monday/...
As of 315 PM Wed...No changes to previous thinking with an
active weather pattern expected through the end of the week and
into the weekend which will result in hazardous boating
conditions with strong winds and elevated seas AOA 6 ft through
the period. Winds will continue N 15-25 kt with large dangerous
seas continuing above 6 ft will persist through at least Sat as
yet another storm system moves through the waters Fri night and
Sat with winds switching to srly and swrly 15-25 kt with higher
MARINE...Small Craft Advisory from 1 AM to 4 PM EST Thursday for AMZ131-
Small Craft Advisory until 7 PM EST Sunday for AMZ150-152-154-