Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/03/16
Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
556 PM CST Fri Dec 2 2016
For the 00Z TAFs, deteriorating weather conditions from south to
north affecting all terminal sites through tonight with light rain
and light snow likely along with attendant IFR cigs and vsbys as an
upper level storm system well to our southwest affects the region.
Expect precipitation to end from north to south late Saturday morning
and afternoon. However, IFR cigs along with MVFR to IFR vsbys will
persist through Saturday afternoon at all TAF sites.
.PREV DISCUSSION... /Issued 350 PM CST Fri Dec 2 2016/
A complex weather system still dominates the short term forecast
period. Current observations show dry air remaining strong at the
surface. However, easterly flow with virga moving north into
portions of the Panhandle region will help to increase moisture in
the mid levels. With lowering bkn to ovc skies across the region,
this process might take a few hours before precipitation reaches
the surface late this afternoon into evening hours. With current
temperatures well into the 40s with an east to northeasterly flow,
precipitation will start as rain across all areas. Going into the
evening hours before midnight, areas across the far western
Panhandles will transition into a mix and then eventually snow.
Light accumulations before midnight are possible across far western
Challenges to the forecast come as we go from midnight into early
Saturday morning. The central Panhandles region is where the
borderline of sub freezing and above freezing temperatures will
likely set up. Latest forecast have a wide range of output ranging
from deep cold air within the dendritic growth zone resulting in a
persistent snowfall, to a warmer solution with drier air in the mid
levels with a mixture of rain/snow for the central Panhandles. Areas
across the southeastern TX Panhandle will remain all rain
throughout this event as temperatures will remain above freezing.
Latest 02/12Z hi-res model and probabilistic data shows the onset of
the precipitation starting between 21Z Friday and 00Z Saturday
starting in parts of the southern Panhandle as it progresses
northward throughout the night. Latest model data continues to track
the main low pressure system well to the south across northern
Mexico. As previously mentioned, current observations shows virga
across portion of the Panhandles. As the precipitation fills in
across most of the region throughout the evening into the overnight
hours, some of the GFS/HiRes WRF output runs does advecting mid
level moisture ahead of the main low pressure system into portions
of the central Panhandles near the dichotomy of temperatures above
and below freezing. This could help enhance low level moisture for
an earlier precipitation initiation time. Other outputs shows drier
air working in from the northwest which may damper QPF amounts as
well. Synoptic forcing will be limited to isentropic lift with the
best timing between 00Z and 12Z Saturday as the better established
temperature gradient sets up. Model consensus shows QPF amounts will
range between around a tenth of an inch in the northwestern areas
over a half an inch in the SE TX Panhandle by 12Z Saturday. Winds
will be out of the east and northeast between 10 to 15 kts.
Precipitation will change back to rain for the entire region by 18Z
Saturday as temperatures again warm up above freezing for all of the
Focus will be on the lingering precipitation chances through the
Not too much has changed from the previous forecast and things seem
to be in line well. Temperature profiles in the lower levels still
should be monitored closely due to the fact our area of snowfall
could change with only a couple degree differences here and there.
The main change was to end QPF and hence snowfall chances after 00Z
Simulated reflectivity from the HRRR (thru 14Z), NMM, and ARW all
have precipitation lingering around Saturday morning, mainly to our
southeast where mostly rainfall should be occurring. As mentioned
already, it will be interesting to see how our temperatures hold up
tomorrow to support mainly rainfall. There could be a transition
zone of rain or snow. The area of all snow could change as well. It
will depend on how much impact precipitation has on column temps.
Beyond the current activity, there is another cold airmass coming
into the area middle of next week. Models have backed off on
precipitation chances, so I was able to collaborate a little with
the neighbors to decrease those chances in the forecast. Since it
was day 5, there wasn`t too much to hang our hat on. A lot can
change between now and then. Most noteworthy was the GFS ensemble
mean for probability of precipitation of 0.10" over a 12 hour
period. The ensemble mean showed about 10-20% chance mainly to our
north across the Oklahoma Panhandle Tuesday through Wednesday.
These low chances really decreased my confidence for any
precipitation during this time period. That being said, if any
precipitation does form, it should be all snow as temperatures are
cold enough Tuesday night to discern p-type easily.
TX...Winter Weather Advisory until noon CST Saturday for the
following zones: Dallam...Deaf Smith...Hansford...Hartley...
Area Forecast Discussion
National Weather Service Bismarck ND
957 PM CST Fri Dec 2 2016
Issued at 947 PM CST Fri Dec 2 2016
Latest satellite imagery shows back edge of stratus cloud shield
progressing east across western ND. Clearing line through KISN and
KDIK with ragged back edge near KBIS. A period of clear skies
last hour and temperature dropped to 17 and has already risen back
to 22. Once back edge moves through central ND, we should see a
quick drop in temperatures, at least for a few hours. Farther
west, temperatures drops have slowed with evening a few rises
along the Montana border during the past hour. In general expect a
slower drop in temperatures west. Finally in the east, steady or
slowly falling temperatures into at least the early overnight
hours with a quick drop toward morning, if they clear out
There was some patchy fog over SD and can not rule out some patchyfog
late tonight over central portions of the state. Latest iterations
of the HRRR have pushed the fog farther east, between Bismarck and
UPDATE Issued at 547 PM CST Fri Dec 2 2016
Latest radar and satellite analysis shows a band of flurries
tracking east across central ND, with stratus across most of the
CWA except for a few breaks over the south central and clearing
skies in the far west. Tough forecast tonight as southerly flow
and warm advection continue to spread west to east across the
forecast area. Most model guidance is showing an erosion of lower
RH from west to east overnight, thus clearing skies. However, this
may allow for the development of fog, especially across the south
central, as noted by the last few iterations of the HRRR. Not real
confident about this right now and will continue to monitor for
development south of the forecast area this evening. Temperatures
may drop over clearing areas west this evening, but exactly how
far remains unclear. East of the Highway 83 corridor looks to
remain cloudy for at least through the evening, and into the
overnight hours over the James River Valley. current forecast has
temperatures dropping quickly in the teens this evening. Not
confident about this either. For now will blend our current
temperatures with a multi-model blend of short term guidance.
.SHORT TERM...(This evening through Saturday)
Issued at 334 PM CST Fri Dec 2 2016
For the near term, now through 00z Saturday, will continue with a
mention of isolated flurries on the leading edge of warm air
advection. Weak returns on radar continue to approach and will
move through south central ND late this afternoon.
Overall, the latest visible satellite imagery loop continues to
advertise cloudy conditions with a couple holes briefly showing up.
Trend overnight will be for some partial clearing in south central
with the HRRR/RAP13 both indicating areas of fog developing around
06z Saturday and continuing into mid Saturday morning. Surface map
indicates 3hr pressure falls getting established over southeast
Alberta into northcentral MT. This is in advance of a surface warm
front and upper shortwave slated to slide through Saturday into
Saturday night. Isentropic lift/upglide per 290K pressure surface
will result in a band of light snow moving into western ND by mid
to late Saturday morning, then shifting into central ND by late
afternoon into the early evening. Snowfall amounts will be minor,
ranging from around one tenth of an inch west and central to around
one half inch across the far northwest and north central through 00z
Sunday. Highs on Saturday around 30F for all but the west where
lower 30s will occur as warm air advection completely pushes through.
.LONG TERM...(Saturday night through Friday)
Issued at 334 PM CST Fri Dec 2 2016
Dry Sunday with some sunshine and highs in the upper 20s north to
lower 30s south and west. Active weather initiates Sunday night
with an approaching strong cold front. This front will push from
northwest to southeast Monday with widespread light snow and
increasing northwest winds. Expecting snow and patchy blowing snow
at this time. Snowfall accumulations look probable across western
and central ND, but models are all over the place on where the
highest amounts will occur. This can be refined in future forecasts.
Following the snow will be the first surge of arctic air this
season, heralding in wind chills as low as 25 below zero Tuesday
through Thursday. We messaged this earlier in a Special Weather
Statement, and now in the Hazardous Weather Outlook to give a
heads up to the public that frost bite can occur to exposed skin
in as little as 30 minutes.
A backdoor or secondary cold front will shift through Wednesday
into Wednesday night delivering more wind very cold air for Thursday.
Both the GFS and ECMWF keep an active period going beyond the extended
with periodic warm air advection snow events which should continue
through next weekend.
High temperatures during the arctic cold event, Tuesday through
Thursday will feature high temperatures in the lower single
digits above zero, with lows in the single digits below zero.
Friday remains very cold as well for all but the far southwest
where mid teens begin to emerge.
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 947 PM CST Fri Dec 2 2016
Generally MVFR ceilings this evening across central ND sites of
KBIS KMOT and KJMS, although periods of vfr possible 00-02 UTC at
KBIS. KISN and KDIK are on the western fringe of a large band of
stratus clouds and are expected to clear out this evening. KBIS
and KMOT expected to clear late evening or early overnight...and
KJMS Saturday morning. Will keep a mention of fog at KBIS late
tonight. Another band of MVFR ceilings and light snow will move
west to east during the day Saturday.
Area Forecast Discussion
National Weather Service Caribou ME
951 PM EST Fri Dec 2 2016
A trof of low pressure will cross the region through Saturday.
High pressure will build across the region later Sunday through
early next week.
.NEAR TERM /THROUGH SATURDAY/...
645 PM Update: No sig chgs to the ongoing fcst. Latest HRRR model
output still indicates the potential of additional lgt to mdt sn
banding ovr N and E Cntrl ptns of the region into the late ngt
hrs, so despite the upcoming break in precip, we will hold on to
higher PoPs a little longer.
Orgnl Disc: The storm that brought significant snowfall to
portions of northern Maine yesterday will continue to move slowly
through the Canadian maritimes. As it does so, a trof will extend
westward across the region. At the same time, an upper level
disturbance will cross the region overnight. These systems will
bring a band of snow showers to portions of northern and downeast
Maine overnight. Any snow accumulation tonight will generally be
an inch or less, although some locally higher amounts will be
possible from the Katahdin region down through Houlton. Lows
tonight will generally range from the upper 20s north and the
lower 30s downeast.
Saturday will be a mainly cloudy day as low pressure continues
to move slowly east of the region and another weak upper
disturbance crosses the area. There will be a continued chance
for a few snow showers, mainly across northern and central areas.
Highs on Saturday will range from the lower 30s north and the mid
to upper 30s downeast.
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
An upper level disturbance will move east of the region Saturday
night with mostly cloudy skies along with a slight chance of snow
showers north, with decreasing clouds across the Bangor and
Downeast areas. High pressure begins to build toward the region
later Sunday with decreasing clouds north and partly/mostly sunny
skies across the Bangor and Downeast areas. High pressure crosses
the forecast area Sunday night through Monday with mostly clear
skies Sunday night and mostly/partly sunny skies Monday.
Temperatures will be at below normal levels Sunday/Monday.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure will cross the region Monday night through Tuesday,
then begin to move east Tuesday night. Partly cloudy/mostly clear
skies are expected Monday night through Tuesday, with increasing
clouds Tuesday night. Uncertainty then develops Wednesday into
Friday regarding the track and timing of several potential lows
and fronts. Precipitation types and totals Wednesday through
Friday will be dependent on the eventual tracks and timing of the
lows and fronts. Generally expect near normal, to slightly below
normal, level temperatures Tuesday through Friday though
temperatures will be dependent on the tracks of the several
potential lows and the timing of several potential fronts.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: Expect mainly MVFR conditions across the northern
terminals through Saturday in sct snow showers with VFR
conditions at KBGR and KBHB.
SHORT TERM: Occasional MVFR conditions are possible across the
north and mountains Saturday night. Otherwise, generally expect
VFR conditions across the region Saturday night into early
Wednesday. Conditions could begin to lower to MVFR levels later
NEAR TERM: Winds/seas are expected to remain below small craft
advisory levels through Saturday.
SHORT TERM: Small craft advisory level conditions are possible
Saturday night into Sunday. Conditions are expected to be below
small craft advisory levels Sunday night into Monday.
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
1004 PM CST Fri Dec 2 2016
Swells offshore are running 5 to 7 feet with 8 second periods, and
winds are east. As a result, issued a high risk of rip currents
for tonight through noon. Mid shift can decide to extend, but
winds are expected to be more south on Saturday afternoon which
should lower rip current risk to moderate (if swells do not get
Also, extended the Coastal Flood Advisory through midnight. Tide
levels at Bob Hall Pier are about 2.2 feet and falling slowly as
high tide occurred about 3 hours ago. That should continue and
hopefully by midnight or shortly after it will be below 2 feet.
Should have less tide levels on Saturday with south winds around
high tide, but it could get close if swells get even higher. Will
let mid and/or day shift handle.
Kept the highest POPs tonight over the north and northwest, but
lowered them farther south. This is based on IR satellite trends
(showing enhanced clouds moving NE), newer HRRR model and previous
4 KM model runs. Mainly rain but could have some thunder
especially out west.
Adjusted temperatures and winds as well. Updates are out.
With seas 7 feet BOY020 and 10 feet BOY019 and seas forecast to
increase on Saturday, have decided to extend the SCA for the gulf
waters through Saturday afternoon. Winds offshore kick up on
Saturday as they shift more to the south, and seas are forecast to
be 5 to 7 near shore and to 7 to 8 feet offshore. Adjusted rain
chances tonight as well, generally lowering chances most areas
based on aforementioned reasoning in main discussion.
.PREVIOUS DISCUSSION... /Issued 527 PM CST Fri Dec 2 2016/
Will be issuing a coastal flood advisory as Bob Hall Pier near 2
feet around high tide.
See Aviation discussion for 00Z TAFs.
Main issue is the convection...whether there will be thunder and
the timing of the rain. Based on GFS vertical velocity profiles
along with 4 km model data (where available), have included
thunder for this evening, generally for the 04Z through about 08Z
time frame. Cigs will be MVFR or IFR tonight, and could fluctuate.
Rain chances will diminish overnight mainly after 09Z but could
have some lingering light rain so have kept -SHRA/-RA in the
forecast. Main activity may mainly be to the north Saturday
afternoon, with front moving more to the north and southern areas
being more in the warm sector. However, upper trough is
approaching and we could get some thunder development in the
afternoon. As a result, have PROB30 thunder most areas (VCTS at
KLRD), with CIGS possibly getting to MVFR later in the afternoon
with the warm front passing to the north especially southern
Will make last minute changes before issuance.
PREVIOUS DISCUSSION... /Issued 407 PM CST Fri Dec 2 2016/
SHORT TERM (Tonight through Saturday Night)...
Patchy rain and showers continue this late afternoon across South
Texas as the coastal trough develops. Some drying is expected,
with activity to wane this evening briefly, before redeveloping
late tonight along increased convergence zone along the coast,
extending northward toward the developing associated surface
boundary near the Victoria Crossroads. Additional shower
development is expected to move out of NE Mexico with the SE-NE
flow in the midlevels aided with divergent flow in the jet stream.
Slight lift northward of the boundary will begin to dry things
from south, however maintained 60-90% for much of the areas north
and along a line from Rockport to George West to Cotulla. The
north movement of the boundary will then begin to retrograde back
to the south as a cold front keeping elevated rain chances through
the evening and overnight hours, with best chances across the
Victoria Crossroads and Northern Coastal Bend. As moisture
continues to run 2+ SD above normal, and increased upper dynamics
come into play, moderate to occasionally heavy rainfall is
expected through Saturday and Saturday night. With model soundings
showing slight drying in the mid levels developing, some storms
may allow for strong gusty winds. Models are also showing CAPE
values reaching near 1700 J/kg and with available shearing from
increased onshore flow just off the surface, a few of the storms
may become strong to possibly severe. However, the overall
concerns are mainly the persistent rains leading to minor flooding
and strong winds within any showers/storms. Strong onshore flow
just above the surface is expected to continue as the coastal
trough deepens. Warmer conditions over the waters will allow for
strong winds to mix down, keeping Small Craft Advisory conditions
through the evening. Hazardous seas will continue through SCA
through the overnight as winds diminish. However winds are
expected to strengthen again heading into Saturday with SCA
conditions to likely continue.
LONG TERM (Sunday through Friday)...
Active weather pattern this weekend continues into Sunday. Main idea
is that a cold front will cross South Texas during the day on
Sunday, with an upper low hanging to the west of the CWA. High rain
chances will continue Sunday and Sunday night, tapering off on Monday
as the upper low finally passes and forcing moves to the east. May be
just enough instability and forcing for thunder, but the primary
threat may be excessive rainfall. Best chances for this appear to be
east and northeast of the Coastal Bend, but localized flooding is
South Texas dries out Monday and Tuesday before another system moves
in on Wednesday. Small chances for rain on Wednesday will end behind
the front, with much colder conditions Thursday and Friday as South
Texas sees its first modified Arctic air of the season.
Small craft advisories will likely be needed in the wake of the
midweek cold front. Models currently are hinting at the possibility
of gusts to gale force Wednesday night and early Thursday.
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 68 77 64 69 56 / 60 60 70 70 70
Victoria 60 73 57 61 53 / 80 90 80 80 70
Laredo 67 80 59 63 52 / 60 30 70 70 70
Alice 66 79 62 66 54 / 60 50 70 70 70
Rockport 67 74 65 67 58 / 70 80 80 80 70
Cotulla 63 70 55 59 50 / 90 60 70 70 70
Kingsville 69 80 65 72 55 / 50 40 70 70 70
Navy Corpus 69 75 68 72 58 / 50 60 70 80 70
TX...High Rip Current Risk through Saturday morning For the following
Coastal Flood Advisory until midnight CST tonight For the
following zones: Kleberg...Nueces.
GM...Small Craft Advisory until 5 PM CST Saturday For the following
zones: Coastal waters from Baffin Bay to Port Aransas out
20 NM...Coastal waters from Port Aransas to Matagorda Ship
Channel out 20 NM...Waters from Baffin Bay to Port Aransas
from 20 to 60 NM...Waters from Port Aransas to Matagorda
Ship Channel from 20 to 60 NM.
GW/86...SYNOPTIC AND MESO
Area Forecast Discussion
National Weather Service State College PA
1033 PM EST Fri Dec 2 2016
A large and deep storm system will move slowly across northern
New England through Saturday, keeping a prolonged period of cool
northwest flow and a gusty wind over the local area. A ridge of
high pressure will slide east across the commonwealth for Saturday
night and Sunday accompanied by fair dry weather and light wind. A
weak frontal boundary will then cross the region Sunday night and
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Cold cyclonic flow over the Great Lakes will keep a blanket of
strato-cu clouds over practically all of the CWA overnight.
Chances for lake enhanced snow will increase as the low level flow
becomes more favorable to steer the snow showers into the northern
mountains. The HRRR shows this support for increased banding by
midnight, and even hints that narrow bands of snow showers could
reach into central areas.
The JST ASOS reported UP for a time so there could be some patchy
freezing drizzle. A light accum of a coating to one inch should
occur across the Laurel Highlands overnight, while the NW mtns
(specifically Warren and Mckean counties see snowfall totals of
1-2 inches with locally higher amounts possible north and west of
the city of Warren. Additional light snowfall Saturday morning
from LES showers could bring 18-24 hour totals to 3 or 4 inches
throughout the typical snowbelt of NW Warren County (and perhaps
portions of Mckean County). However, these amounts will be just
under LES Advisory Criteria of 3 inches/12 hours.
Min temps early Saturday will vary from the upper 20s across the
higher terrain of nrn and wrn PA, to the l-m 30s elsewhere.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
The stacked low pressure over moves over the Canadian Maritimes.
The mean WNW boundary layer flow off the Great Lakes will be
persistent with multiple narrow bands of mainly lake effect
snow expected to spread a little more inland (developing south
across the Laurel Highlands) and last into Sat Night.
Clouds will be pesky and linger across much of the CWA right
through the day Saturday.
Max temps Saturday will be slightly colder across the north and
west, but slightly warmer than today (Friday) across the
Susquehanna River Valley. Still, these numbers are within a few
degs of normal for the first part of Dec.
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Late Sat night and Sunday brings a brief respite as high pressure
builds east across the state. Sunday evening and night, a period
of light snow is looking likely as a northern stream shortwave
races through the region with a burst of warm advection. QPF looks
to be on the order of a tenth of an inch or less, but occurring
overnight many places could see their first coating of snow of the
young season by Mon morning. Snow is more likely in the NW than
Another ridge moves through on Monday as progressive weather
pattern becomes more active. On Tues there is decent agreement in
bringing the SW US upper low up through the Ohio Valley as a
shearing out shortwave and diffuse surface low. Unless cold air
damming traps enough chilly air in the low levels to make for some
freezing rain, the precip type with this midwest system looks to
be mainly rain.
The end of the week brings some model disagreement with the
GFS/GEFS being faster than the ECMWF with the next large upper
trof and frontal system. Either way, precip looks like a good bet
around the Thu/fri period as all solutions eventually bring this
trough through. So predictability is increasing, but timing issues
remain. Best bet for precip at this point is mainly rain over the
SE as decent push of warm air lifts ahead of the system, with a
rain/snow mix further north where warm air will not infiltrate as
Behind the trough, looks like a chilly weekend in store with a
potential sharp dropoff in temps.
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Satellite continues to show a pretty solid deck of clouds covering
all of Central Pennsylvania. Ceilings ranging from low MVFR in
the west and north, to VFR in the east. Additionally, radar shows
an area of light snow and rain moving across norther tier of
Central Pennsylvania this evening. This precipitation is falling
as occasional light snow in KBFD, to occasional light rain in
KIPT. This area of precipitation corresponds well to shortwave
depicted on models.
Persistent WNW flow will keep threat of lake precipitation into
the mountains overnight into Saturday. After passage of shortwave,
flow settles down, which may add somewhat to organization of lake
snow bands. HRRR and RAP has the idea of somewhat organized lake
snows developing into the NW after 03z...then continuing into
Saturday as well.
Overall, MVFR to occasional IFR in snow in KBFD, with same thing
possible at KJST. Will wait and see the evolution of exactly where
banding sets up, and adjust TAFs as appropriate.
Downsloping flow east of the mountains should result in better
conditions further east. Mainly VFR expected at
KUNV/KIPT/KMDT/KLNS through the TAF window. Temporary dips to
MVFR cigs overnight at KAOO.
The entire region will continue to see breezy conditions last
through the next 24 hours.
Sat...SHSN with ocnl IFR vsbys at KBFD/KJST, mainly in the
morning. VFR elsewhere.
Sun...Light snow/reduced vis possible at night, mainly NW Mtns.
Mon...No sig wx expected.
Tue...Mixed precip/low CIGs possible across the nrn mtns, with a
mdtly heavy 0.50-1.00 rainfall expected across much of Central and
NEAR TERM...La Corte
Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
849 PM MST Fri Dec 2 2016
Issued at 838 PM MST Fri Dec 2 2016
Latest water vapor loop showed the mid/upper shortwave trough
axis from east through south central WY this evening. Lift ahead
of trough across portions of southeast WY was waning, indicative
of diminishing radar reflectivities. HRRR showing similar trend
this evening, with possibly a few snow flurries still possible.
Lowered PoPs to 10 percent or less for the remainder of the
evening. With light southerly flow tonight, cannot completely
eliminate fog potential for low lying/valley locations. If it
forms, it will be brief as winds shift to southwest toward
morning. High winds still on target by Saturday morning at
Arlington and Bordeaux, so no changes to the warnings. Lowered
temperatures a few degrees for areas east of I-25.
.SHORT TERM...(This evening through Sunday)
Issued at 147 PM MST Fri Dec 2 2016
Light snow showers have been falling from Laramie to Cheyenne
over the past few hours ahead of a weak upper trough that is
positioned across western WY. Still not expecting much
accumulation through the evening as lift is rather weak. Snow will
come to an end by the late evening as subsidence moves into
southeast WY behind the shortwave. The weather concern in the
short term will be the increase in winds by late tonight into
Saturday morning over the wind prone areas of southeast WY. The
850mb CAG-CPR gradient rises to 55-60 meters shortly after sunrise
on Saturday. This looks like a favorable pattern for Bordeaux with
the sfc trough just to the east of the Laramie Range. The office
wind model is giving some high probs of high winds for Bordeaux.
Went ahead and upgraded to a High Wind Warning for Arlington and
Bordeaux, but left the southern Laramie Range out. Confidence was
not high enough to include that zone even though isolated gusts to
50-60 mph will be possible.
It will be a breezy day over much of southeast WY, but winds will
decrease some over the wind prone areas by aftn as the gradient
weakens. Zonal flow aloft will prevail through Sunday. It will be
the warmest on Sunday with highs rising into the 40s to the east
of the Laramie Range. The CAG-CPR gradient will remain around 50
meters, so it will still be windy over Arlington. The precip
threat will remain slim after the snow showers wind down this
.LONG TERM...(Sunday night through Friday)
Issued at 230 PM MST Fri Dec 2 2016
Confidence remains fairly high that we will be experiencing some
of the coldest temperatures we have seen so far this season by
midweek, confidence remains good that we will see snow over the
mountains late Sunday through Wednesday...but fairly low on
seeing significant snowfall across our eastern areas early to mid
next week. The pressure gradient Sunday night should increase with
strong west to southwesterly winds for areas along and west of
I-25 Sunday night into early Monday ahead of an approaching Arctic
cold front. We have good agreement amongst the 12Z guidance that
we will see that front move quickly southeast across our region
during the day on Monday, with readings dropping into the teens
on the plains and subzero to single digits west of I-25 by Tuesday
morning. Coldest readings by mid-week look to be -10 to zero for
elevations above 6000 ft msl Wednesday morning and single digits
for the lower elevations. Basically, the current forecast doesn`t
have the lower elevations in the eastern areas going above
freezing until Friday. The snowfall forecast is a bit trickier.
The general trend of the models is to have the heavier snow over
Colorado but the ECMWF still depicts more widespread heavier snow
farther north Tuesday into Wednesday across southeastern Wyoming
and the western Nebraska Panhandle while the GFS remains less
robust. Carried higher snow chances in the Snowy and Sierra Madre
Ranges starting Sunday night through Tuesday night with a chance
of snow east along and north of the Colorado border with lesser
chances farther northeast towards the South Dakota border. With
westerly 700 mb winds around 35 kts during the day Monday through
Wednesday, the models are not hitting the mountains as hard
amount-wise with orographic snow production. Our most likely
scenario as we can see it now would be for a few inches to fall
over the Sierra Madre and Snowy Ranges with lesser amounts
eastward. This far out that can change so stay tuned.
.AVIATION...(For the 00Z TAFS through 00Z Saturday afternoon)
Issued at 415 PM MST Fri Dec 2 2016
Occasional MVFR cigs/MVFR-IFR vis in light snow will continue at LAR
and CYS thru 03Z then taper off with the passage of a weak
shortwave. Winds will become light southerly this evening with MVFR
cigs lingering at LAR and CYS until 07Z. Elsewhere, VFR cigs will
prevail. Cannot rule out patchy fog toward morning for the western
valleys between LAR and RWL. Southwesterly winds will become breezy
after 16Z Saturday with gusts 20-30 kt.
Issued at 300 AM MST Fri Dec 2 2016
Minimal fire weather concerns will continue through next week as
cold temperatures will remain over the area. Winds will increase
Saturday as low pressure begin to approach from the west. Another
winter storm system set to move into the area Monday into
Wednesday that may bring widespread accumulating snow.
WY...High Wind Warning from 3 AM to 3 PM MST Saturday for WYZ106-110.
Area Forecast Discussion
National Weather Service Wilmington NC
938 PM EST Fri Dec 2 2016
High pressure will be reinforced from the northwest and as a
result the weather will remain dry and cool through early
Sunday. The high will move offshore Sunday night. A strong and
complex low pressure system will likely bring good soaking
rains to the forecast area early to mid next week. A strong
cold front late next week will usher in the coldest and driest
air of this late Autumn season thus far.
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 915 PM Friday...The sfc trof, or one could even call
it a reinforcing cold front, drops south across the ILM CWA
from late this evening thru and during the pre-dawn Sat hours.
This can be seen with the latest RAP model using its progged sfc
pressure pattern and 1000-850mb thickness fields respectively.
Around midnight, the RAP 1000-850mb thickness fields range from
1325 northern portions to 1342 southern portions of the ILM CWA.
By daybreak Sat, the 1000-850mb thickness fields drop to 1312
north portions and 1330 south portions of the ILM CWA. The FA
will get some decent CAA and slightly lower sfc dewpoints but
will be short-lived, ending by midday Sat. Only clouds for
tonight will be mainly thin Cirrus given upstream trends and
various model rh time height displays across the FA thru Sat
morning. Have only lightly massaged the latest min temp fcst
and the hourly sfc temps and dewpoints. Mainly as a result of
the sfc winds decoupling prior to the sfc trof passage later
tonight. This a result of the decent rad cooling conditions and
winds having decoupled ahead of the sfc trof.
As of 215 PM Friday...Dry, zonal flow across the Eastern United
States will continue through the remainder of the afternoon and
tonight. The bulk of the column will remain dry however some
cirrus will potentially overspread the area overnight as a
storm system across the Southwest United States begins to
direct some moisture toward the Carolinas. Scattered cirrus and
just enough wind will likely hinder optimal radiational cooling
tonight, nevertheless the typical cool spots may dip into the
lower to mid 30s.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
As of 215 PM Friday...The atmosphere will be in transition
during the short term period as high pressure loses its
influence to a developing coastal front and approaching
southern stream system. As a result, rain chances will be on
the rise, especially by Sunday night given the proximity of the
coastal front and increasing isentropic lift. Followed a blend
of MAV/MET numbers for the highs/lows each period, however
expect non-diurnal temp trends along the coast Sunday night with
the coastal front moving onshore late.
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM Friday...Very active weather slated for the long
term with some minor uncertainties yet to be hashed out.
Monday`s weather will be quite unsettled with high pressure to
our north being overrun by moderately strong warm advection.
Rainfall should initially be light to moderate as there is
little deep layer forcing and all of the resulting upglide will
be confined to the lower levels. Rainfall rates increase heading
into Tuesday as height fall and PVA deepen the ascent. The
interplay between two surface lows may dictate temperatures and
their positions are not agreed upon superbly between various
guidance. Drying should be rapid Tuesday night as this
conglomerate system lifts northward. Wednesday and Thursday will
feature a series of moisture-deprived cool fronts moving
through from the northwest. The latest front Thursday night will
usher in some true Arctic air.
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...VFR is expected for this 24 hour TAF valid period.
Winds of 3-8 kt, highest at the coastal terminals, will veer
from W- NW to NNW-NNE overnight. No significant clouds
expected. After sunrise winds speed will increase to 8-12 kt.
High clouds will be on the increase with mid level clouds moving
in from the west late in the day.
Extended Outlook...VFR. Moderate confidence for MVFR/TEMPO
IFR late Sun into Mon. Highest confidence of IFR is Mon night
NEAR TERM /THROUGH TONIGHT/...
As of 930 PM Friday...SCEC for the ILM NC waters remains in
The winds and seas have been tweaked to take into the account
of the passage of a sfc trof or weak cold front, dropping from
south to north late this evening and into the overnight hrs.
After its passage, winds will veer to the NW-NNW at 15 to
possibly 20 kt across the ILM NC Waters, and NNW to NNE at 10-15
kt and possibly up to 20 kt.
Significant seas initially will have an influence from a weak
SE 1 to 1.5 foot, 8 second period ground swell. After the
passage of the sfc trof, locally produced 3 to 5 second period
wind waves will become dominate.
As of 215 PM Friday...Surface high pressure will continue to
build across the waters from the W-NW through tonight. A minor
surge will build south across the waters generally after
midnight. The increase in northerly winds as a result of the
surge will allow for a period of Small Craft Should Exercise
Caution conditions primarily for the NC waters which will carry
into the short term period. Along the Cape Fear waters seas are
expected to build to 4-5 ft, especially away from the inshore
waters given the orientation of the fetch.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 215 PM Friday...Northerly winds will diminish during
Saturday afternoon as high pressure builds eastward. The high
will slowly progress off the Mid-Atlantic coast by Sunday night
allowing the flow to veer to a northeasterly direction beginning
late Saturday night. A coastal front will become better
established by Sunday night and as it lifts northward the wind
is expected to sharply veer to a southerly direction late in the
period. Seas of 4 to 5 ft Saturday morning off the Cape Fear
coast will subside during the afternoon. Seas should remain
below 3 feet during Sunday then begin to build again Sunday
LONG TERM /MONDAY THROUGH WEDNESDAY/...
As OF 3 PM Friday... Winds will be light on Monday but the
wind direction is uncertain. High pressure to our north will be
eroding along the coast as a coastal warm front develops ahead
of low pressure developing over the Gulf. By Tuesday the winds
should swing to the south and ramp up to where wind or seas will
necessitate Small Craft Advisory. Wind turns offshore by
Wednesday and decreases as dual-barreled high pressure lifts out
to the north.
Area Forecast Discussion
National Weather Service Norman OK
937 PM CST Fri Dec 2 2016
Main update was to increase POPs.
Widespread rain continues to spread northeast across the area.
Every mesonet station across the southwestern half of the forecast
area has measured rain and the precipitation area continues to
look solid in the short-term as it moves into central and
northern Oklahoma. Therefore have increased POPs to categorical
across most of the southwestern two-thirds of the area, and
increased POPs to likely almost everywhere. Temperatures in the
northwest have stayed up so far, but those will begin to fall as
the precipitation spreads into that area with airmass cooling and
dewpoints rising with the precipitation. The temperature and even
wet bulb temperatures across far northwest Oklahoma looks like it
should remain above 32 so frozen precipitation looks unlikely in
our forecast area. Forecast min temperatures still look
.PREV DISCUSSION... /issued 509 PM CST Fri Dec 2 2016/
Please see the 00Z aviation discussion below.
Rain will continue to make its way out of TX from the SW this
evening. There is high confidence in at least MVFR cigs developing
over most terminals by sunrise...with even lower (IFR) cigs
expected shortly after that. Lightning strikes appear very
unlikely right now. Winds will remain east to southeast for most
of the forecast period.
PREV DISCUSSION... /issued 411 PM CST Fri Dec 2 2016/
Primary forecast concern is focused on increasing rain chances
tonight through Saturday.
Currently, a dynamic 500 mb trough continues to dig east/southeast
across the southwestern U.S. From latest WV imagery, the trough
axis extends from the northern western high plains of WY/NE/SD to
the Gulf of California. Ahead of it, increasing moisture return
from both the Pacific and the Gulf of Mexico have combined to
result in increasing stratus through the day from the Rio Grande
Valley to Oklahoma. Additionally, isolated to scattered showers
have been developing off and on across portions of western north
Texas and southern Oklahoma, primarily in response to a weak 850mb
boundary and isentropic response around 310 and 315 K. RAP
soundings through the day have done an excellent job capturing
With continued warm air advection ahead of the slowly approaching
500mb trough, profiles will continue to moisten through the low to
mid levels. In response, showers and rain chances will gradually
increase in coverage from western north Texas into Oklahoma through
the overnight hours into early Saturday. Overall, temperature
profiles in the low levels across the region will remain above
freezing. As with the previous forecasters (BRB/VM/MAD, etc.)
sticking towards the deterministic models for temperatures
although the blends have been catching on to the warmer trend.
Therefore expect precipitation to remain as rain overnight across
the region. However, across far northwestern Oklahoma, the RAP,
GFS, and ECMWF continue to show 0-5km show a weak warm nose of 1
to 3 C wet bulb temperatures, which would result in some partial
melting, but surface wet bulb temperatures are likely to remain
just above freezing. Therefore, kept the slight chance of snow,
but with higher chances for Rain. If any snow does develop, it
would pose no impacts to roads or visibility.
Widespread scattered rain will continue through Saturday as the
500mb trough continues to churn over western Mexico. The highest
rain chances will continue to slide to the east and southeast
overnight into Sunday. As the 500mb low begins to lift eastward
across Mexico into Monday morning, towards the lower Rio Grande
Valley, rain chances will persist across the Red River valley and
increase across southeastern Oklahoma before ending into early
A colder, more winter-like pattern will emerge by midweek. A broad
trough will position itself over the central U.S. Still some
noticable differences between guidance suites of the
GFS/ECMWF/Canadian with the 500mb trough. The GFS remains about 8 to
12 hours faster than the ECMWF overall, with the ECMWF more
aggressive with the depth of the trough. This has made for a
tricky temperature and potential precipitation forecast for
Wednesday into Thursday. Similar to the night shift and similar to
the Canadian model, split the difference between the two.
Currently expecting some frosty temperatures, especially Wednesday
night into Thursday, where lows will dip into the lower teens
across northern Oklahoma to the upper teens to lower 20s toward
the Red River. Additionally, with the frontal passage Wednesday
afternoon/evening, some light snow may develop, with little to no
impacts to travel expected at this time as any snow will be
flurries to very light. The big impact will be strong north winds
which will result in overnight wind chills in the single digits
across northern and central Oklahoma Wednesday night.
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 43 46 38 53 / 90 80 50 10
Hobart OK 42 45 38 53 / 100 70 50 10
Wichita Falls TX 45 47 41 55 / 100 80 50 20
Gage OK 35 42 31 54 / 80 60 30 0
Ponca City OK 40 47 37 55 / 60 70 50 10
Durant OK 45 47 42 53 / 90 100 70 20