Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/23/16
Area Forecast Discussion
National Weather Service Amarillo TX
633 PM CST Thu Dec 22 2016
.UPDATE...An ejecting vort max from upper low over northern Arizona
has resulted in increasing precipitation coverage across eastern New
Mexico and the western Texas Panhandle. Have updated grids to
increase PoPs along projected path of precipitation band and to
account for possibility of mixed precipitation along the core of
this band. As precipitation band moves east across the region, drier
air will filter in behind the vort max along with increasing
downslope winds. This should effectively end any further chances for
precipitation by Friday morning except over the far southeastern
Texas Panhandle.
Bieda
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 32 58 32 64 42 / 60 5 5 0 20
Beaver OK 31 58 26 60 42 / 60 5 5 0 40
Boise City OK 28 55 26 57 34 / 50 5 0 0 20
Borger TX 35 61 33 65 45 / 60 5 5 0 30
Boys Ranch TX 33 60 30 65 40 / 80 5 5 0 20
Canyon TX 31 58 32 65 41 / 60 5 5 0 20
Clarendon TX 32 59 33 64 45 / 50 10 5 0 30
Dalhart TX 31 57 25 59 36 / 70 5 0 0 20
Guymon OK 32 58 26 62 40 / 60 5 5 0 20
Hereford TX 32 58 32 64 41 / 70 5 5 0 20
Lipscomb TX 32 59 28 61 45 / 60 5 5 0 50
Pampa TX 32 59 32 63 44 / 50 5 0 0 30
Shamrock TX 33 56 31 61 47 / 50 20 0 0 50
Wellington TX 33 56 33 62 49 / 50 30 5 0 50
&&
.PREV DISCUSSION... /Issued 526 PM CST Thu Dec 22 2016/
AVIATION...00Z TAFs...Another band of precipitation is approaching
the Panhandles this evening, with KDHT expecting mixed precip thru
03/06Z. This precipitation band should arrive at KAMA and KGUY BTWN
23/02Z and 23/04Z. CIG and VIS could briefly drop with this band,
with IFR to MVFR conditions possible. Will monitor and amend as
necessary. Otherwise, as the precipitation band moves thru in
association with passing weather disturbance, southerly winds will
increase to BTWN 15 to 25 kts at all terminals. Winds will veer to
the southwest around 20 to 30 kts as upper disturbance clears the
region AFT 23/10Z with VFR conditions at all terminals thereafter.
Bieda
PREV DISCUSSION... /Issued 353 PM CST Thu Dec 22 2016/
Discussion...
Noteworthy items include the ongoing precipitation
which has impacted visibilities at times earlier across the local
area, as well as the windy conditions forecast this weekend.
Simulated reflectivity from the HRRR and NAM 4km both have a break
in precipitation. Precipitation should push out northeast by late
afternoon/early evening with a small break in precipitation behind
these showers. But it wont be too long behind this break for
precipitation to pick back up. Temperatures are warm enough now that
the entire forecast area is at or above freezing at this point (20Z).
This will help keep our chances for snow limited as the lower levels
are forecast to stay above freezing for a good portions of the next
24 hours. I`m not really worried about frozen precipitation at the
surface at this time. Guymon is the only site reporting snow at 20Z,
and even then this will not last much longer. There is also some
warm air advection going on today along with some dry layers in the
forecast soundings which should hamper our frozen precipitation
chances at the surface as well. I am expecting rain showers tonight
for the remainder of this precipitation event.
Big story will be this weekend, mainly Christmas day as conditions
are forecast to be windy. Showers and thunderstorms will be possible
on Saturday night and into Sunday as a large upper level trough
approaches the Four Corners region. The greatest chance for
precipitation will remain along the eastern half of the Panhandles.
Models are also hinting at some instability across the area, so
there is a small chance for some isolated thunderstorms that night,
mainly for our counties across the east. Severe weather is not
expected at this time. Lingering showers and a few rumbles of
thunder on Christmas Day will rapidly give way to clearing skies and
drying conditions. Wind speeds around 30 to 35 mph with gusts to
around 50 to 55 mph are likely in some areas. These strong winds
coupled with dry relative humidities will result in conditions
favorable for explosive fire growth. Also, any outdoor holiday
decorations could be thrown around as projectiles given the windy
conditions forecast across the local area.
Sunday evening through Thursday Once the wind dies down on Sunday
night, fairly tranquil weather conditions are expected through mid-
week. Upper level flow will become more zonal, and then southwesterly
as a weak upper level ridge builds over the Gulf of Mexico, and
another upper level low churns in the Pacific off the Baja Coast. The
evolution of this system could bring us another chance for precip
later in the week, but right now it appears that a strong surface high
pressure could keep the weather fairly quiet the majority of the
week.
FIRE WEATHER...
Very windy and rapidly drying conditions are expected across the
Panhandles on Christmas Day. This will lead to elevated and probably
even critical fire weather conditions across a portion of the area.
Relative humidity values will drop throughout the day and approach 20
percent during the afternoon. Southwest winds will increase by late
morning to around 30 to 35 mph with gusts up to 50 mph. Fire officials
should closely monitor the forecast for updates in the days leading
up to this event.
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
98/29
Area Forecast Discussion
National Weather Service Denver/Boulder CO
333 PM MST Thu Dec 22 2016
.SHORT TERM...(This evening through Friday)
Issued at 333 PM MST Thu Dec 22 2016
A potent Pacific storm system have moved onshore the U.S. near
San Diego and will continue to move northeast today. By tonight
the 500 mb trough axis will be located across eastern Utah to
central Arizona. Colorado will be under a moist south- southwest
flow. Wind direction is not favorable for advisory level snows in
the mountains, but areas above 9000 feet could see up to 6
inches. The HRRR, RAP, and ESRL HRRR have been showing mesoscale
bands forming across Summit County tonight, increasing our
confidence in the potential for 3-6 inches, with locally higher
amounts possible. The northern mountains should see 3-5 inches.
By the time the rich Pacific moisture crosses the continental
divide in Colorado, the majority of the precipitable water will
have fallen as snow across the southwest and central mountains,
leaving the east slopes of the Front Range foothills dry tonight
and tomorrow. There is ample model agreement in a dry scenario
from Weld County west to the Front Range and west of I-25.
But the weather could still be very interesting tonight across the
plains of northeast Colorado. The Pacific storm system dug a ways
south and tapped into sub- tropical moisture, resulting in a plume
of relatively warm moist air above 750mb. HRRR, RUC, EC, NAM, and
GFS soundings all indicate a layer of +4-5C temperatures 2000
feet off the ground. Wet bulb effects of evaporating precipitation
into that layer do not look like enough to drop the temperature in
that layer cooler than +1-2C. HRRR and and ESRL HRRR both show a
band of light precipitation forming east of the Denver metro area
after about 2 AM and moving northeast. QPF amounts will be 0.05 or
less associated with the band. Given the warm layer above surface
temperatures in the upper 20s, freezing rain is a real possibility
tonight. Confidence in this scenario is low for precipitation
forming across the Eastern Plains, but higher near the Kansas
border. However, if precipitation forms like the high res models
indicate, confidence is relatively high it would fall as freezing
rain given the thermodynamic profiles tonight. Any accumulating
ice would result in slick bridges and overpasses and potentially
slick spots on the rest of the highways and roads. Any
precipitation that forms should exit the state before sunrise
Friday.
Tomorrow...any ice accumulation across Eastern Colorado should
melt quickly with temperatures warming above freezing by 9 or 10
AM and high temperatures on Friday reaching the low 50s most areas
east of the mountains with clearing skies. Snow in the mountains
should taper off by midday after the trough axis moves northeast
into Kansas/Nebraska and a much drier northwest flow impacts
Colorado.
.LONG TERM...(Friday night through Thursday)
Issued at 333 PM MST Thu Dec 22 2016
Dry and mild weather will prevail Friday night through most of
Saturday, before the next storm system begins to impact the area
by Saturday afternoon or evening (Christmas Eve). Q-G lift will be
increasing by nightfall with snow likely developing in the
mountains despite the strong southerly flow with poor orographics.
Surface low pressure will move into eastern Colorado and deepen
overnight.
By Christmas (Sunday) morning, the upper level trough will begin
to swing into the state, with strong Q-G lift noted right over the
forecast area. Models remain very consistent regarding the path
of the upper low right across the Denver area. With this track, we
could still see snow spread down onto the plains. However, this
would only be a brief shot before strong downslope kicks in and
leads to strong gusty west/northwest winds over the plains. The
mountains will continue to see snow and blowing snow through most
of Christmas with strong orographics and sufficient wrap around
moisture. Accumulations should be moderate, but hard to pin down
amounts this far out. Initial thoughts for the high country would
be in the 4-8 inch range. It should be noted we can`t be totally
confident in the solutions despite their excellent agreement, as
the storm itself is still well out over the Pacific. These dynamic
systems can sometimes develop farther south so will continue to
monitor and adjust forecasts as necessary.
Beyond that, the weather should be quiet by Monday and most of
Tuesday, before the next weather system moves in from the
northwest in strong flow aloft. This should bring more snow to the
high country and bouts of gusty winds to the entire forecast area
late Tuesday into Wednesday and Thursday. Temperatures should
average near normal levels, with perhaps a slight downward trend
through Thursday. At this time, don`t see much threat of any snow
in the lower elevations.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 333 PM MST Thu Dec 22 2016
Winds will remain light all terminals throughout the period. VIS
also not expected to be an issue. The challenge for tonight is the
potential for a rare but potentially high impact freezing rain
event at KDEN. Overnight surface temperatures will be in the upper
20s. The high resolution models develop a band of light
precipitation very near KDEN and then move it northeast. Best bet
on timing is around 2 AM for onset of precipitation at KDEN. Have
included freezing rain from 09-12Z in the KDEN TAF even though
the chance of any precipitation falling at KDEN is low, because of
the potential impacts to the airport. If precipitation develops,
MVFR conditions are likely. Radar trends will be watched very
closely for the development of the precipitation band tonight. Any
ice accumulation will be light and should melt quickly after 9 AM
as temperatures warm above freezing. Friday during the day looks
like a good day to fly in and out of the Denver metro area.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Schlatter
LONG TERM...Barjenbruch
AVIATION...Schlatter
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
654 PM CST Thu Dec 22 2016
...Dense fog advisory issued for coastal counties and Coastal
waters...
.DISCUSSION...Marine/advection fog has formed over portions of
the Laguna Madre and the Nearshore Gulf waters in association
with a weak cold front and warm dew point air flowing over
slightly cooler coastal waters. Local Coast Guard station,
observation sites and webcams are reporting or indicating
visibilities dropping below one quarter mile or less. Conditions
should persist or worsen over the next several hours with the fog
advecting inland impacting coastal sections of Willacy and Cameron
counties. Will continue to monitor the progress of the fog and if
Dense fog moves or develops farther inland the Dense Fog Advisory
may have to be expanded.
&&
.DISCUSSION...Updated for latest marine discussion below.
&&
.MARINE...A dense fog advisory has been issued for the Laguna
Madre and the near shore gulf waters through mid morning Friday.
See discussion above.
&&
.PREV DISCUSSION... /issued 604 PM CST Thu Dec 22 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...A weak cold front has passed south of all TAF
locations with Northeast winds expected through the evening. An
area of sea fog/low stratus deck has formed over the Laguna Madre
and pushed inland affecting KHRL with IFR cigs and LIFR cigs at
KBRO. Meanwhile...conditions at KMFE will lower a bit more slowly
starting out with MVFR cigs. Conditions will deteriorate through
the overnight hours and do expect another round of LIFR
cigs/visbys as low level moisture lingers. However...there is
still some uncertainty as to how low visbys will drop as a wind
shift to the SE occurs overnight into the morning hours Friday.
Conditions will improve to VFR levels by Friday afternoon.
PREV DISCUSSION... /issued 244 PM CST Thu Dec 22 2016/
SHORT TERM (Tonight through Friday Night): The biggest issue
will be the fog forecast for tonight. Signs point to another round
of dense fog for the lower valley as a weak front essentially
stalls over the area, and the location of the boundary will impact
fog development. The HRRR shows persistent dew points in the mid
to upper 60s and very light winds for the lower valley tonight,
supporting heavier fog formation. The NAM forecast sounding at 12Z
for BRO shows a saturated profile below a low level inversion at
around 1200 feet, and therefore placed a mention of dense fog for
that area in the forecast for tonight. The oncoming shift will
once again need to refine the effort as trends shape up.
Southeast winds should reestablish themselves during the day Friday
as high pressure shifts east and pressures fall across the high
plains ahead of a short wave trough. Rain chances will end for the
CWFA as any remnant surface boundary dissipates or gets pushed back
north of the area. Partly to mostly cloudy skies will continue and
temperatures will remain above average during the short term with
50s and 60s at night and mid 70s to near 80 on Friday.
LONG TERM (Saturday through Thursday):
As the next H5 trough races northeast from the four corners into
the northern plains, a surface reflection low will sweep through
those region, with a cold front trailing around it. Saturday into
Sunday will see modest southeast winds wrapping into this develop
storm system, which will help push local temperatures will into
the 80s, especially on Christmas Sunday. Models continue to back
off the progression of the tail end of the front, keeping our
region in the warm sector. Deeper Gulf moisture and weak
instability will possibly spark a few showers from time to time
Monday into Tuesday, depending on the proximity of the front. With
the showers in the vicinity and increased cloud cover, highs early
next week will be slightly lower than the weekend, but still
running above normals for the last week of the year.
MARINE:
Now through Friday night: A weak cold front will pass slowly
through the Lower Texas coastal waters but will quickly dissipate
and allow surface high pressure to resume over the western Gulf of
Mexico. Light to moderate winds and low to moderate seas will
prevail along the Lower Texas Coast during the forecast period.
Saturday through Monday: Onshore flow continues through the
weekend into early next week as the next storm system moves
through the central plains. Models continue to push the storm
track further north, so gradient will not be very tight as it
crosses the plains. Thus the southerly winds will likely not
reach advisory criteria through the period. Strongest winds would
be on Sunday, with possible 15 to 20kt range for the Laguna Madre.
Continuous southeast flow will keep seas elevated through the
period, generally 4 to 5 feet.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 9 AM CST Friday for TXZ256-257.
GM...Dense Fog Advisory until 9 AM CST Friday for GMZ130-132-135-150-
155.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
69/59/62
Area Forecast Discussion
National Weather Service Caribou ME
930 PM EST Thu Dec 22 2016
.SYNOPSIS...
Low pressure will pull away from the region tonight into the
Maritimes. High pressure is expected to build across the area on
Friday. A cold front will cross the area Saturday and strong high
pressure will build toward the region from the northwest Sunday.
&&
.NEAR TERM /THROUGH FRIDAY/...
9:30 PM...The last of the precipitation will be ending over the
next hour in eastern Washington County. The main concern over the
next few hours is for areas of fog with reports of locally poor
visibility. The fog situation should improve overnight as the
pressure gradient increases and the wind picks up a bit. A weak
weather disturbance is visible on satellite moving across Quebec
that may clip northern areas with a snow shower in spots
overnight. Made some adjustments to the grids for the remainder
of tonight based on the latest observations, and the latest
satellite and radar trends.
Previous discussion...
Snow will be winding down this evening with temps remaining above
normal into Friday.
18Z analysis showed low pres moving across the state w/the 2nd low
moving off the southern New England coast. The latest runs of the
RAP and HRRR in line w/this analysis. It looks like low pres will
merge off the coast of Maine and pull away tonight. Snow has been
winding down across the n per the latest radar loop. Reports of
moderate snow across portions of central and interior Downeast
this afternoon. Radar indicated decent returns in these areas.
Slight adjustments were made to the QPF and snowfall amounts
keeping 1-3 in the aforementioned areas and less than 1 inch
across the northern areas. Coastal areas were seeing rain as temps
warmed well into the 30s. Another band of precip is set to move
across the interior Downeast and coastal region later this
afternoon into the evening. This precip associated w/50 kt
jetstreak at 700mbs. Temps look like they will cool down allowing
for rain to go to a period of snow along the downeast coast
w/some accumulation before ending. Upper trof moving across the
region will aid in ending the snow near or after midnight. Cooler
air will filter into the region overnight allowing temps to drop
back into the teens and 20s. Low lying areas will see 15-20 as far
s as into the Central Highlands and interior Downeast. This could
lead to some wet roads icing back up overnight.
At the sfc, high pres to our s is forecast to ridge across the
region on Friday while aloft a disturbance is forecast to slide
across the region. Mid level lapse rates look like they will
steepen and there is some weak forcing. This would allow for the
potential for some showery type of precip. The caveat to this is
that the deep moisture is lacking w/the bulk residing at 850 mbs.
Attm, isolated snow showers/flurries possible and kept precip
chances 20-30% across the western areas. Daytime temps will
continue to run above normal w/upper 20o to lower 30s northern
1/2 while central and downeast forecast to hit mid 30s. The coast
will hit 35-40F.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
High pressure will slide east of the mid atlantic coast
Friday night. As it does so, high clouds will begin to increase
overnight. Low temperatures will be mild for this time of year
with low to mid 20s across much of the area. Clouds continue to
thicken up early Saturday in advance of an approaching short wave
from the west. Some light precipitation will develop later
Saturday morning and continue into Saturday afternoon as the
disturbance crosses the region. The precipitation will be in the
form of light snow across the north with perhaps an inch or so of
accumulation by late afternoon. Across central and downeast light
snow will mix with rain, and even change to all rain close to the
coast. Any snow accumulation there will be less than an inch. High
temperatures on Saturday will be unseasonably mild, with low to
mid 30s north and upper 30s to lower 40s downeast. Somewhat colder
air will move in for Christmas eve night but it will still well
above normal for this time of year. Expect mostly to partly cloudy
skies across the north and partly cloudy to mainly clear downeast.
No travel problems are expected on Christmas Day as Canadian high
pressure builds toward the area from the northwest. Expect mainly
sunny skies across the region with highs ranging from the low to
mid 20s north and lower 30s downeast.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Sunday night will be clear and quite cold as good radiational
cooling conditions will be in place. Monday will see
increasing clouds with precipitation was again overspreading the
area by afternoon, as an area of low pressure tracks to our
north. This system will bring another round of snow to northern
areas later Monday and Monday night and a mix of snow and rain
downeast. Colder air will move in behind this system for Tuesday
and Tuesday night. Dry and cold conditions will return for
Wednesday as another Canadian high builds in from the northwest.
Another system could bring another round of snow or mixed
precipitation by Thursday.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: LIFR in areas of low cloud and fog will improve to MVFR
later tonight. It looks like MVFR for all terminals right into
Friday morning. Conditions are expected to go VFR for KBGR and
KBHB later Friday morning. MVFR cigs look to hang on across the
northern terminals right into the afternoon.
SHORT TERM: VFR Friday night. MVFR with possible IFR Saturday
afternoon in snow north and snow/rain mix south. VFR Saturday
night though Sunday night. MVFR and possible IFR once again later
Monday and Monday night in snow north and snow or mix south.
Outlook for Tuesday is VFR except possible MVFR conditions in isld
snow showers and stratocu ceilings across the north. VFR all areas
Wednesday.
&&
.MARINE...
NEAR TERM: Winds are forecast to increase this evening to 15 to 20
kt w/gusts hitting 25-30 kt. Seas will be building to a range of
4-6 ft. The wind will drop off later Fri morning as low pres
pulls away. Seas look like they will stay up longer around 6 ft
especially over the outer zones as a swell component remains.
SHORT TERM: Winds/seas are expected to remain below small craft
advisory levels Friday night and then increase to small craft
advisory levels Saturday through Sunday.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 10 AM EST Friday for ANZ050>052.
&&
$$
Near Term...CB/Hewitt
Short Term...Duda
Long Term...Duda
Aviation...CB/Hewitt/Duda
Marine...CB/Hewitt/Duda
Area Forecast Discussion
National Weather Service Dodge City KS
735 PM CST Thu Dec 22 2016
.UPDATE...
Issued at 735 PM CST Thu Dec 22 2016
Calls to spotters indicate most of the precipitation across the SW
zones is falling in liquid form (either rain or freezing rain).
Snow is becoming increasingly unlikely and took out of the weather
grids. Showers will move quickly with light QPF. limiting impacts.
That said, HRRR continues to spread widespread light precipitation
over SW Kansas overnight. Temperatures are just below freezing at
most locations, and if freezing rain becomes the dominant type, a
short-fused advisory may be required.
UPDATE Issued at 642 PM CST Thu Dec 22 2016
Realigned pop and weather grids through tonight based on latest
radar and model trends. HRRR appears to have the best grasp on
reality, with a light mix reentering SW KS, and the large mass of
light rain/mix across the NW TX panhandle. HRRR suggests this
precip will flirt with the southern border for the next several
hours, but any QPF will be light. As warm advection and strong
LLJ kicks in after midnight, precipitation will trend to being
more liquid, but again very light. Temperatures will hold steady
or slowly rise tonight. Will monitor for any freezing rain
reports, as it doesn`t take much to cause problems. Increased wind
grids a few knots toward morning with the strong low level jet,
and increased high temperatures a couple degrees Friday with
sunshine and downslope.
&&
.SHORT TERM...(This evening through Friday)
Issued at 230 PM CST Thu Dec 22 2016
A weak disturbance moving through the area will bring a chance of
precipitation this evening into the early overnight period.
Precipitation looks to fall as mostly rain this afternoon with an
occasional mix of snow or freezing drizzle. Freezing drizzle or
snow will be possible this evening through around midnight,
otherwise expect mostly cloudy skies. Precipiation chances will be
confined across central and south central Kansas after midnight
but this should move out of the area by sunrise tomorrow. Winds
will generally be from a southerly direction through tonight as a
dome of high pressure shifts eastward with a trough of low
pressure setting up across eastern Colorado. Cloudiness decreases
tomorrow with mostly clear skies anticipated by tomorrow evening.
Winds are expected to shift to a northerly direction tomorrow as a
weak cold front slides through the area. As for temperatures, lows
tonight look to dip to around freezing with highs tomorrow
reaching to the low 50s to around 50 degrees.
.LONG TERM...(Friday night through Thursday)
Issued at 230 PM CST Thu Dec 22 2016
Partly cloudy skies and dry conditions are expected Friday night
through Saturday as an upper level ridge moves over the Rockies
and Plains. Meanwhile, a strong upper level trough/low will dig
into the Western United States Saturday, then into the Rockies
Sunday. This system then pushes northeastward into the Northern
Plains Sunday night into Monday morning. Cloudiness will increase
Saturday night as this system approaches with cloudy skies
anticipated by sunrise Sunday. As of now, far western Kansas looks
to be dry slotted with this system with decreasing clouds from
west to east as we progress through the day Sunday. Scattered
showers and embedded thunderstorms will be possible across central
and south central Kansas Sunday morning then push eastward out of
the CWA Sunday afternoon. A dry weather pattern is progged by the
models during the beginning of next week with the next system
moving into the area mid to late week. As for temperatures, highs
will generally range from the upper 40s to upper 50s Saturday and
Sunday then dip into the 40s Sunday through the mid part of next
week. Lows in the low to mid 20s are expected Friday night then
only dip into the 30s to lower 40s Saturday morning ahead of the
next system. Lows in the teens to 20s are anticipated through the
remainder of the extended forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 500 PM CST Thu Dec 22 2016
Weakening shortwave will continue to produce scattered -SHRASN
through this evening. NAM model suggests GCK northward for this
light precipitation, while HRRR suggests a more southerly
solution. With this dichotomy, just left VCSH in the TAFs for a
few hours this evening. Any precipitation will be light with
impacts on aviation flight categories minimal. MVFR cigs will
gradually improve overnight as lift from shortwave wanes. After
06z, strong LLWS expected with a strong 850 mb LLJ progged of
50-60 kts. This will also keep nocturnal winds gusty and elevated
overnight, gusting as high as 30 kts at DDC. After 15z Fri, winds
will weaken and veer NW under a clearing sky.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 56 23 51 / 60 10 0 0
GCK 34 52 22 53 / 50 0 0 0
EHA 29 55 29 57 / 50 10 0 0
LBL 31 56 25 57 / 60 10 0 0
HYS 33 50 21 49 / 40 10 0 0
P28 32 55 26 52 / 30 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Turner
SHORT TERM...Hovorka_42
LONG TERM...Hovorka_42
AVIATION...Turner
Area Forecast Discussion
National Weather Service Wilmington OH
1000 PM EST Thu Dec 22 2016
.SYNOPSIS...
Surface high pressure will build east across the region tonight
into Friday. Most of Friday looks dry with rain chances increasing
Friday night with the approach of the next frontal system. Rain
chances will diminish Saturday afternoon after the passage of the
frontal system. A chance of light rain will return with warm
temperatures on Christmas day.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A persistent stratocumulus shield over eastern Ohio has finally
just about cleared through the ILN forecast area, with just some
sections of the far eastern counties (Licking/Fairfield/Hocking)
still affected. Once these clouds are gone, increasing
cirrostratus (20kft-25kft) will still remain in place. This should
help limit the potential for significant cooling overnight, even
as winds are becoming fairly calm across the region. Not
surprising to see some slight drops in visibility, but HRRR signals
have been fairly consistent in suggesting that any potential for
dense fog will remain northwest of the ILN forecast area.
Though the clouds over the east have temporarily kept temperatures
higher than expected, overall the current forecast trends are in
line with observations, and thus no changes were made to the min
temp forecast.
Previous discussion >
Zonal mid level flow with surface high pressure building east
across the region overnight. Latest satl imagery shows post
frontal low clouds eroding across ILN/s western counties. This
trend will continue with low clouds diminishing through the
evening, resulting in mostly clear skies for a period late this
evening. Moisture in the form of high and mid level clouds will
increase late tonight. Lows to range from the lower 20s nw to the
mid 20s se.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
In zonal flow pattern surface high pressure to slide east of the
region Friday. Next progressive mid level shortwave to track
through the Great Lakes Friday night and Saturday. Ahead of this
shortwave, favorable isentropic lift develops by Friday evening.
Expect most of the day to remain dry and have a slight chance west
late in the afternoon. This chance increases to categorical Friday
night across most of the FA as 50 kt low level jet and associated
lift comes into play. High temperatures on Friday to range from
the upper 30s nw to the mid 40s se. In strong waa regime, under
the influence of a 50 kt southerly low level jet expect non-
diurnal temperature trace Friday night. With rising temperatures
Friday night, have mainly rain across ILN/s FA.
Given favorable lift have continued categorical pops early
Saturday across the southeast ahead of sfc cold front. Behind the
shortwave expect a temporary break in the precipitation due to
weak subsidence.
The weak cold front will stall across the far southern parts of
the CWA. Expect considerable cloudiness Saturday with highs from
the upper 30s northwest to the upper 40s southeast. Chance pops
for rain to continue mainly across the southwest Saturday night
closer to the frontal boundary as ridge builds across the eastern
CONUS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Upper ridge will be in place across the eastern CONUS to start the
period. For Sunday, a surface low is forecast to ride up the west
flank of the upper ridge to the northern plains, while a warm front
pushes across the ILN area. This will bring a chance of showers
which will diminish by Sunday night as the front lifts north. A cold
front will follow on Monday, with showers likely. High pressure and
drier conditions are expected Tuesday. Another low and frontal
system may impact the region with more showers Wednesday into
Thursday, with snow possibly mixing in at night.
Above normal geopotential heights combined with warm advection on a
southerly low level flow will produce much above normal temperatures
Sunday and Monday, when highs will reach the 50s and 60s. Closer to
normal highs around 40 are indicated for Tuesday through Thursday
under cold advection at the surface and aloft.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
The edge of the borderline VFR/MVFR stratocumulus clouds is now
moving east through the region, and should clear the ILN/CMH/LCK
TAF sites in the next hour or two. After this occurs, VFR
conditions are expected through the overnight, outside of some
possible MVFR fog at LUK.
Tomorrow, winds will very gradually increase in strength from the
SE, as high clouds begin to thicken and lower. By late afternoon,
mid-level clouds are likely to be in place, with rain showers
likely holding off until evening. Once the rain showers move in,
MVFR (and eventually IFR) conditions will be expected.
OUTLOOK...MVFR/IFR ceilings and visibilities are possible at
times from Friday night into Monday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...AR
NEAR TERM...Hatzos/AR
SHORT TERM...AR
LONG TERM...Coniglio
AVIATION...Hatzos
Area Forecast Discussion
National Weather Service North Platte NE
934 PM CST Thu Dec 22 2016
.UPDATE...
Issued at 934 PM CST Thu Dec 22 2016
Just hoisted a winter weather advisory for portions of
southwestern and central Nebraska. The HRRR and 00Z NAM solution
now has a band of light precipitation across southwestern into
portions of central Nebraska late tonight into Friday morning.
Temperatures will hover in the upper 20s to around freezing
during the greatest threat for precipitation. This will also hit
right at commute time in the morning so timing figured into the
issuance of the advisory. By late morning, temps will rise back
into the mid to upper 30s, ending the freezing precipitation
threat. Turning to the main storm this weekend, with the latest
NAM, beginning to become more concerned about a freezing rain
threat over northern Nebraska late Saturday night into Christmas
morning. Like last night`s model runs, the greatest threat for
accumulating snow continues to be over the northeastern panhandle
and northwestern sandhills.
&&
.SHORT TERM...(This evening through Friday)
Issued at 323 PM CST Thu Dec 22 2016
The latest near term projections continue to indicate the
potential for mixed precipitation overnight tonight across
southwest Nebraska and northeast through our north central zones.
The models suggest the closed low currently over northern Baja
will rapidly advance east to southern Colorado and open to a wave.
The main PV anomaly with the wave is then shown to advance
northeast across Kansas Friday reaching the upper Mississippi
River Valley late in the afternoon. As broad large scale forcing
increases ahead of the system, solid moisture will advect
northward over the High Plains and reach the CWA as early as this
evening. Soundings across southwest Nebraska northeast through
north central Nebraska reveal rapid saturation both in the lower
levels and within the DGZ. As the precipitation expands northeast
from southwest Nebraska we anticipate a change over to a mix or
even all snow. The previous shift eluded to the loss of saturation
in the DGZ as dry air invades the upper levels, leading to drizzle
concerns. Bufkit soundings still hint at the possibility, so will
continue a slight chance mention in the grids, but agree with the
previous shift that the potential is low and if fzdz is realized,
then accumulations would be a trace or less. The Ptype forecast is
somewhat questionable given marginal thermal profiles for a change
over to snow and the timing of the arrival of the dry air aloft.
We decided to keep Ptypes simple as possible, only focusing on the
potential impacts of rain changing to snow and if freezing drizzle
is realized. As for snow amounts, qpf with the system is light,
thus most locations will only see a dusting or possibly as much as
a tenth of an inch.
The rapid progression of the system will allow for transitory
shortwave ridging to build into the high plains late Friday.
Precipitation will end from southwest to northeast through the
day. Temperatures will largely return above average for most
locations. Highs in the 30s are likely for northern Nebraska, but
mid to upper 40s are likely across southwest Nebraska. Elsewhere
lower 40s are forecast.
.LONG TERM...(Friday night through Thursday)
Issued at 323 PM CST Thu Dec 22 2016
Friday night through Thursday...a storm is over the Gulf of Alaska
is forecast by all models to lift through Nebraska Sunday. The sfc
low triple point moves from Swrn Neb to Ncntl Neb Sunday afternoon.
Areas along and east of the triple could see an isolated
thunderstorms...maybe more...leading to scattered thunderstorm
coverage.
A locally developed multimodel severe weather ensemble procedure has
trended west favoring thunderstorms across Scntl Neb Sunday which
could easily lift north and northwest through the forecast area.
This convection would feed into a deformation zone forecast to
develop across Northwest Nebraska Sunday afternoon.
It is uncertain how far south arctic air will move in ahead of this
system. A lead short wave will move through Srn Canada Friday and
this will tug arctic air south into the Dakotas Saturday. There may
be enough cooling at night for periods of freezing rain or drizzle
Saturday night. This cold air should quickly erode as south winds
increase Sunday morning leading to all rain.
Once the upper low lifts north of Nebraska Sunday afternoon...a rain
snow line will move rapidly east through Western and North Central
Nebraska. All models indicate a mix of freezing rain and sleet
before change over to snow. Snow chances decrease Sunday night.
The wind forecast is very modest increasing west and northwest winds
to 25 to 30 mph late Sunday afternoon. The model consensus indicates
35 mph winds at 00z Sunday evening using 500m AGL winds mixed down
to the sfc. There is a brief period of 60-70kt 700mb winds which
will pass over the region late Sunday afternoon and evening. This is
a fast moving storm moving at 30 mph so these strong winds may not
mix down.
The snow forecast is similar to WPC with close to 6 inches across a
small portion of Northern Sheridan County...Pine Ridge. The ECM and
NAM are the srn solns with the Storm track while the GFS and
ensemble are farther north basically sparing the forecast area of
significant snow. The SREF was in the middle of the model cluster.
Later forecasts may trend north or south as the storm is still 3
days out.
The storm will pull arctic air into the region Monday morning but
the upper flow is so progressive that temperatures will moderate
Tuesday. Another weak cold front will move through Thursday. The
forecast is dry Monday through Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 604 PM CST Thu Dec 22 2016
Ceilings will continue to fall this evening as an upper level
disturbance lifts northeast across southwestern into northeastern
Nebraska. Light freezing drizzle will be possible at the KLBF
terminal toward 12z Friday Morning. Ceilings may drop as low as
1000 FT AGL as well. Ceilings will fall tonight at the KVTN
terminal, but should remain VFR and no freezing drizzle is
expected ATTM. Skies are expected to clear out Friday afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 2 AM CST /1 AM MST/ to 10 AM CST /9
AM MST/ Friday for NEZ038-059-069>071.
&&
$$
UPDATE...Buttler
SHORT TERM...Jacobs
LONG TERM...CDC
AVIATION...Buttler