Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/30/16
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
500 PM MST Thu Dec 29 2016
00Z TAF CYCLE
VFR conditions are expected at TAF sites and northward through the
next 24 hours. Moisture advected by the subtropical jet could
result in isolated showers over the southern fringe of the
forecast area (mainly in the mountains) tonight and Friday
morning. Rain and snow showers will move into the state from the
west Friday evening as an upper level trough approaches from
.PREV DISCUSSION...308 PM MST Thu Dec 29 2016...
Cloudiness mostly of the high, thin variety will continue to
stream northeast across much of New Mexico tonight. The thickest
cloud cover will be found across the southern part of the area and
could yield a few rain or high elevation snow showers near Ruidoso
but precipitation amounts will not be significant. Temperatures
will rebound on Friday ahead of the the first in a series of quick
hitting weather disturbances that will impact the area Friday
night and Saturday. Another system will move through New Year`s
Day with more rain and snow especially favoring western and
southern areas. Confidence is growing in a significant change to
colder and more impactful wintry weather the first full week of
Looks like 2016 will end much like it began-- rather active. While
we`re not looking at blockbuster mountain snowfalls with any one
individual system, the cumulative totals do look pretty good.
Anticipate at least minor to moderate winter wx travel impacts
for higher elevations of western and northern NM as well as the
San Juan Basin-Four Corners Friday night- Saturday, and near/above
6500 feet for NYD with the focus shifting more into central/southern
12Z model guidance as well as latest HRRR still insist keeping
measurable QPF south of our area through 12Z Fri. Boundary layer
remains very dry across our southern zones and best low level
moisture/WAA advection above the NW-SE oriented frontal zone
appears to extend from SE AZ to NM bootheel to near KELP and not
expected to shift much farther north. Few very weak echoes across
southern Catron, southern Socorro and southwest Lincoln counties
evidence of top down moistening. Cannot completely rule out
isolated measurable precip for areas near Ruidoso/Dunken tonight
but not going to be significant. Already seeing western edge of
cirroform cloud shield shift eastward over southeast AZ.
Lee-side surface trough quickly reestablishes on Friday as mid-
level westerlies strengthen ahead of a shortwave trough, formerly
the system west of Baja, that has now trended slower and wetter/snowier
for some areas Friday night into Saturday. Increasing precip
chances after sunset Friday with main window from about 06Z Sat to
00Z Sun. The GFS and ECMWF are now more bullish with QPF in the
Four Corners Friday night where 1-2 inches of slushy snow very
possible for Farmington- Bloomfield-Aztec especially if GFS
verifies. Other feature of interest will be a secondary surge of
cold air into NE/EC New Mexico early Saturday that could set up
favorable upslope and enhanced region of precip as upper wave
translates eastward. Precip types here do look tricky with
potential for sleet/freezing rain. Otherwise, thinking snowfall
totals broadly in 2 to 6 inch range near and above 6500 feet with
higher west facing slopes favored. The GFS is noticeably colder
than the NAM at 700mb with this wave and wet bulbing effects could
come into play and be rather significant at locally lowering snow
The NYE wave should exit Saturday evening with precip coverage
trending downward from late evening to several hours after
midnight but the break will be short-lived. An even stronger
and colder shortwave/upper low will cross the area NYD. 12Z
models maintain previous trend of tracking the primary low center
toward NM bootheel by 00Z Mon but a nice deformation precip band
sets up east of the Divide toward the RGV late Sunday before the
wave pivots east- northeast Sunday night. The Upper Gila and SC
ranges could do quite well, as well as the Sandia/Manzanos,and
700mb temps of -2 to -4 will allow accumulating snow down to 6500
feet if not a bit below. Monday/Tuesday next week transitions to a
much winder/mountain wave/westerly orographic pattern with Arctic
air making a return visit to eastern NM by Tuesday/Wednesday and
dominating much of next week. Looks messy with precip types in the
east and west facing slopes of the northern mountains should do
particularly well with snowfall. KJ
For just a short while longer, NM will remain between weather
systems with a deep upper level trough over the eastern U.S. and a
cut-off low over the open waters of the eastern Pacific. High
level moisture is pushing northeastward ahead of the Pacific low
and into NM, giving widespread high clouds over much of our
forecast area. These will gradually drift out of the area
overnight, but lower- based clouds will filter into the southern
sections of NM, largely south of the ABQ fire weather forecast
area. Overall, tonight`s low temperatures will not stray too much
from the observed lows of last night and early this morning, and
RH recoveries will be excellent in most zones, the exception being
the Sangre de Cristo mountains where much lower dewpoints will
By Friday, the aforementioned Pacific low will have made landfall
into southern CA. Variable cloudiness and shifting winds over NM
will offer some temperature changes, primarily in the northeastern
plains of the state where readings will escalate some 10 to 15
degrees due to a lee side trough and the consequential downslope
breezes. This will push all zones at or above normal temperature-
wise with the largest departures in the northeastern plains. Despite
some stronger breezes along the highlands-high plains interface,
smoke dispersion/ventilation rates will remain poor on Friday. Also
of note, the best subtropical moisture is projected to stream south
and east of NM through Friday, and thus it will not be until Friday
night and Saturday when precipitation will be observed.
The remnants of the weakened low will cross NM Friday night into
Saturday, and as precipitation spreads from west to east, snow
accumulations of any significance will generally be confined to
higher elevations with lighter amounts in the valleys and lower
elevations of northern and central NM. Still, wetting liquid
equivalent amounts of 0.10 or greater seem plausible for many
central to western zones Friday night into Saturday. In addition to
the precipitation, a cold front will back into northeast NM
Saturday, disrupting the above normal temperature trend.
Another low pressure system will arrive on the heels of the Friday
night and Saturday system, and this second disturbance should weaken
some as it crosses the southern border of NM during the daytime
Sunday. Cooler air will filter into western NM Sunday with a second
shot of rain and high elevation snow leading to a few more inches of
accumulation upon the highest peaks.
Winds strengthen into Monday as a perturbed and stiff westerly flow
aloft sets up. Slightly below normal temperatures in the central to
western zones will persist along with slightly warmer than average
readings in the eastern plains of NM Monday. Any precipitation would
be focused over the north central to northwestern zones, and
ventilation is currently advertised to be fair amidst the stronger
westerlies. A quasi-similar regime would hold through Tuesday before
the flow buckles on Wednesday, spilling much colder air into NM.
Despite some periods of breezy to occasionally windy conditions next
week, critical fire weather is not forecast at this time. 52
Area Forecast Discussion
National Weather Service Caribou ME
1017 PM EST Thu Dec 29 2016
Low pressure developing off of the Delmarva this afternoon will
rapidly intensify as it lifts into the Gulf of Maine tonight. It
will cross central sections of the state overnight. A weak area of
low pressure will cross the region Saturday night into Sunday morning.
.NEAR TERM /THROUGH FRIDAY/...
Update 10:15 pm: Have raised snow accumulation for zone 15 to the
north of Bangor based on developing banding and for zone 32 based
on latest expected storm track. Will extend winter storm warnings
into both of these zones.
Sfc low developed this mrng off the Delmarva and has dropped 10mb in
4 hrs. Greatest pressure falls are centered to the northeast of the
low cntr and over Nantucket MA at this time. Latest RUC and NAM are
slightly too weak with sfc low as of 18z this aftn. Snow has mvd
into wrn parts of CWA this aftn and wl continue thru the ovrngt.
Hires models are hinting that sfc low wl mv acrs Houlton by 12z
Fri, dropping an average of 22-24 mb in 12 hours. This is in
agreement with NAM and GEM. Latest GFS tracks low west while EC
tracks the low east, thus have gone with the compromise and hv
allowed for low to mv ovr Houlton Fri mrng. This keeps all snow
north of a Dover- Foxcroft to Danforth line.
Warm air wl be drawn in on strong srly flow ovrngt switching pcpn
ovr to rain as far north as Bangor to Calais this evng. Locations
in the Upper Penobscot Vly will likely see a rain-snow mix
tonight. May see svrl hours of sleet in southeast Aroostook for a
time right around daybreak, enough to drop the snow totals but
still retaining warning amnts. Snow should be fairly close to a
10:1 ratio and hv reduced areas of blowing snow back to patchy for
As low tracks north thru the state, expect gusty east winds thru
midnight to near 30 MPH. Winds will back around to the northwest as
the low slides into New Brunswick toward morning with gusts
increasing to near 35 MPH in the afternoon. This may result in
scattered power outages through tomorrow.
Further to the south, coastal zones will likely see SW winds exceed
40 MPH around midnight and into the morning hours therefore will
continue with High Wind Warning.
Expect temps to rise during the course of the nighttime hours
tonight before dropping acrs the nw after 07z as low tracks acrs
cntrl sxns. Lopres wl pull twd the Gaspe Peninsula tomorrow aftn
with snow showers ending drg the aftn.
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
The models are in good agreement through the period. A low
tracking northeast across eastern Quebec will bring a few
lingering snow showers to northern Maine early in the period. By
Saturday morning higher pressure will briefly ridge into the area,
another frontal system will move into southwestern Maine Saturday
afternoon. Saturday evening the warm front will across western
Maine into Downeast Maine. The frontal system will track across
the state overnight and by Sunday morning the front will be along
the Maine and New Brunswick border. Higher pressure will once
again build across the region, as the front moves into New
Brunswick and will remain through the end of the period.
Loaded a blend of the GFS/GEM/NAM/ECMWF to smooth out the minor
differences in the models. Loaded NAWAVE4 for seas in the coastal
waters. Loaded windgust by factor tool. For QPF used GFS.
.LONG TERM /MONDAY THROUGH THURSDAY/...
The extended models are in good general agreement, a low over the
Gulf of St Lawrence may bring a few lingering snowshowers to
northern Maine otherwise higher pressure will build across the
area. The GFS and ECMWF differ about 6 hrs on timing of the next
system moving into western Maine. The GFS moves it in around 2 AM
Tuesday morning, the ECMWF around 8 AM. Both models move it to the
central portions of the state by mid day, and slowly moves it
through the state. Finally moving it to New Brunswick Wednesday
afternoon, higher pressure will briefly build in, but will be
moved out Wednesday evening as a secondary cold front moves
through the state. By Thursday morning the front will be east of
the area. High pressure will ridge across the area and will remain
through the end of the period.
Loaded a blend to smooth out the minor differences in the models.
Loaded NAWAVE4 for seas in the coastal waters. Loaded windgust by
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: MVFR restrictions will give way to IFR this evening as
pcpn moves in from the west. Snow expected for terminals north of
HUL. May see several hours of -SNPL at HUL around daybreak. BGR
will likely see -RASN after 00z then becoming -RA overnight before
going back to -SHSN after 12z. BHB will see -RA remainder of TAF
valid time. LLWS expected after 00z through 09z tonight as
southeast winds increase to between 45-50kts out of the southeast.
Confidence too low to include at BGR.
SHORT TERM: VFR conditions with a few lingering snowshowers across
northern Maine early in the period. IFR conditions in snow will
move across the region from the Saturday night into Sunday
morning. VFR conditions will return to the area by early afternoon
Sunday and will remain through early morning Tuesday. Conditions
will deteriorate to IFR in snow at all sites by late morning
Tuesday and will remain IFR through the end of the period.
NEAR TERM: Storm warnings will be in effect this evening through
tomorrow afternoon. Seas will range from 12-20 feet in swrly
SHORT TERM: A small craft warning will be in effect through the
period with near gale force winds early. Winds and seas will
subside below SCA briefly early Sunday evening, however will build
again above SCA by late evening.
Splashover is possible tonight around the time of high tide. High
tide at Bar Harbor is 1107 pm tonight. A storm surge of 1-2 feet
is possible. The astronomical tides are not all that high, but
some minor splash over is possible around the time of high tide.
Minor splash over is also possible around the time of high tide
Friday morning. A coastal flood advisory has been issued for the
high tide late this evening.
ME...Winter Storm Warning until noon EST Friday for MEZ002-005-006-
Winter Storm Warning until 4 PM EST Friday for MEZ001-003-004-
Winter Weather Advisory until 7 AM EST Friday for MEZ016-017.
High Wind Warning until 1 PM EST Friday for MEZ029-030.
Coastal Flood Advisory until 1 AM EST Friday for MEZ029-030.
MARINE...Storm Warning until noon EST Friday for ANZ050>052.
Area Forecast Discussion
National Weather Service Wilmington OH
912 PM EST Thu Dec 29 2016
An upper level trough will move east through the Great Lakes
tonight, bringing snow showers and snow squalls to the region this
evening. Snow showers will diminish on Friday, as high pressure
builds into the southeast states, extending northward into the
Ohio Valley. A series of low pressure systems will move northeast
through the region from Saturday through Monday, bringing
additional chances for precipitation.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
With initial batch of snow showers east, and shallower moisture
arriving, have reduced pops and intensity of snow showers through
tonight. Added flurries that will fall from a shallow moist and
unstable layer between about 2500 to 5000 feet agl.
The middle Ohio Valley is currently located in a regime of deep-
layer WNW flow. While there is evidence of a weak surface trough,
along an axis from roughly Port Huron MI to Springfield IL, this
trough is not well defined -- just a slight 20-30 degree wind
shift and little change in boundary layer air mass. There is also
very little going on at 500mb and above, with the upper jet
curving well south of the region, and no real indication of
notable forcing further aloft. The features to monitor are located
in between, showing up nicely on recent RAP13 runs. A compact
shortwave at 700mb is currently moving through northern Illinois,
and will move WSW across Indiana and Ohio over the next few hours.
As this occurs, there will be a rapid cooling/moistening of the
850mb-700mb layer, which will have a pronounced effect on weather
conditions over the region -- a significant deepening of the
boundary layer. The clear skies observed over much of the forecast
area this afternoon will be quickly replaced by thick convective
stratocumulus in a very-well- mixed near-surface environment. The
genesis region for this change in atmospheric conditions is
presently over NE Illinois, as evidenced by the curved band of
clouds on visible satellite and the developing 20-30 dBZ echoes
between Chicago and Springfield -- and, to note, not the
unidentified non-meteorological echoes over southern Indiana.
Recent HRRR runs / 12Z WRF-NMM / 12Z SPC-WRF runs suggest that a
broken band of snow squalls will cross the ILN forecast area from
WNW to ESE between 21Z and 02Z, with continued scattered snow
shower activity following behind. Current observations suggest
this may be a little too fast, maybe by an hour or so. As this
activity crosses through the area, the mixed layer will extend far
enough aloft to support wind gusts in the 30-35 knot range, with
steepening lapse rates that will allow for convective instability
through about 8kft AGL / 700mb. This instability will overlap the
dendritic growth zone with increasing relative humidity within the
-12C to -18C layer, resulting in efficient snow production for
what should be a relatively brief period of time. Across multiple
model datasets as viewed in BUFKIT, values for these parameters --
such as low-level lapse rates, wind speeds, SBCAPE, and DGZ
depth/RH -- fit nicely within WFO ILN (Kurz/Haines) research from
verified snow squall cases. To no surprise, this is also indicated
on the WFO BTV snow squall parameter (Banacos/Loconto/Devoir).
Despite this, there are a few factors that might keep this from
being one of the truly high-impact snow squall events -- the lack
of a classic arctic front to focus low-level convergence,
relatively un-hazardous (warm) antecedent conditions, and the lack
of upper support (shortwave or PV anomaly) to increase lift.
The ultimate expectation is that most of the CWA will be impacted
by the initial broken band of snow showers / snow squalls, some of
which may become strong enough to support hazards of rapid
accumulations and loss of visibility. Once the initial band has
passed, RH in the dendritic growth zone decreases significantly
with southwestward extent, and continued snow shower activity will
be much more likely further to the northeast (especially
along and north of a rough line from Richmond IN to Chillicothe
OH). Forecasting accumulations for this sort of scenario is
difficult, as some locations impacted by the squalls or repeated
snow showers could quickly pick up a half inch (possibly up near
an inch) while other locations (especially in the southwestern
sections of the CWA) may receive little to no accumulation.
An overall diminishing trend in snow shower coverage and wind
gust intensity is expected after 06Z, with continued cold
advection heading into Friday morning, and lows in the middle to
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
A few persisting snow showers or flurries may occur on Friday
morning in central Ohio, but overall, conditions are expected to
dry significantly -- with clearing skies from west to east over
the course of the afternoon, with rising heights. Some wind gusts
of 20-25 MPH may continue through the day.
A switch to warm advection will allow temperatures to slowly rise
on Friday night into Saturday morning, ahead of the next low
pressure system moving through the Great Lakes. With a southern
stream of moisture helping to develop precipitation across the
area, a mix of rain and snow is expected to develop -- favoring
rain in the ILN CWA on Saturday afternoon, but perhaps switching
back to snow again as temperatures cool Saturday evening. Though a
cold front will be moving southeast into the area, it will
eventually stall on Saturday night and fail to make it south into
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A weak cold front will move south/southeast through the area early
Sunday morning. Models have hinted at some moisture/light
precipitation lingering along/south of the Ohio River behind the
front Sunday morning. This may allow for a few light rain/snow
showers in southern parts of the FA during the morning hours before
sufficient surface warming changes all/any precipitation to rain. As
the frontal boundary stalls just south of the FA during the day
Sunday, overrunning moisture is expected to work back northward as
the front begins to pivot back north into the Ohio Valley by Sunday
night into Monday.
Although some of the details still differ slightly, global models
have come into better agreement regarding strength/amplitude and
timing of a S/W which will move from western Texas early Monday into
the Ohio Valley Tuesday morning. At the surface, a strengthening low
pressure system in the central Plains will push toward the Ohio
Valley, and as such, expect that temperatures will trend well above
normal Monday even as WAA-induced scattered showers linger in the
FA. Have maintained likely PoPs Monday evening into early Tuesday as
the system moves through the region.
Colder air will begin to slowly build back into the area late
Tuesday into Wednesday as a cold front moves through and the upper
level trough continues to dig southward into the upper Midwest and
Great Lakes region. Temperatures may even trend below normal towards
the end of the period as the CAA regime persists in the Ohio
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Snow showers associated with a mid level short wave and low level
cold advection will impact TAF sites tonight. Main effects will be
at DAY CMH LCK and ILN where MVFR is expected, with lesser impact
at CVG and LUK which will probably stay VFR. All sites should
become VFR by Friday morning as drier air moves in amid decreasing
short wave energy.
West winds will be quite strong, with gusts near 40 knots to
start, subsiding somewhat Friday while gusts remain over 20 knots.
OUTLOOK...MVFR ceilings and visibilities are possible Saturday
afternoon into Monday.