Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/07/16
Area Forecast Discussion
National Weather Service Bismarck ND
1000 PM CST Tue Dec 6 2016
.UPDATE...
Issued at 943 PM CST Tue Dec 6 2016
No significant changes with the late evening update. Surface
observations at Rolla, Rugby and Jamestown continue to indicate
consistent visibilities under a mile. Expect open areas from the
James River Valley to the Turtle Mountains are still well within
Blizzard criteria with near zero visibilities.
Area webcams from western portions of the Blizzard warning show
improving conditions. Will allow the Warning to expire as
advertised in Minot and Sherwood, Wishek and Napoleon, at
Midnight.
In western North Dakota, wind chills are currently around 20 below
zero. We did extend the wind chill advisory farther east to
include all areas west and south of Lake Sakakawea and the
Missouri River, as well as the Bowbells and Stanley areas north of
the lake.
Winds will continue to slowly diminish across western and central
North Dakota tonight. A few flurries or light snow showers are
possible over the central, but any light accumulating snow will be
confined to far eastern portions of the James River Valley into
the Turtle Mountains.
UPDATE Issued at 811 PM CST Tue Dec 6 2016
We have allowed the blizzard warning to expire for portions of
western and central North Dakota. Mainly from Bowbells and Stanley
south through Beulah, Glen Ullin, Bismarck and Selfridge. Winds
continue to slowly diminish and visibilities have greatly
improved. However, per the NDDOT travel is still not advised in
these areas. Any streets and roads that have not been cleared may
still be impassable.
The Blizzard Warning Remains in effect through midnight for areas
like Minot and Sherwood in the north central, and Napoleon and
Wishek in the south central.
The Blizzard warning will remain in effect for eastern portions of
central ND, mainly from the Turtle Mountains to the James River
Valley. Expect strong winds to continue here through the night
with near zero visibilities, especially in open country.
UPDATE Issued at 548 PM CST Tue Dec 6 2016
We have extended the blizzard warning through 6 am Wednesday
morning for eastern portions of central ND. this included the
Turtle mountains through the James River Valley. Some cities
include Bottineau...Rugby...Harvey...Carrington and Jamestown.
With some of the heaviest snow accumulations over the northern
James River Valley into the Turtle mountains, and strong winds
expected to continue through the night, we extended the warning
through 6 am Wednesday for the areas mentioned above.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 149 PM CST Tue Dec 6 2016
Continued blizzard conditions through this evening highlight the
short term forecast.
Extended the Blizzard Warning through 02 UTC form Burke county
through Bismarck and Mandan...Fort Yates and Linton and through
06 UTC for points further east into the James River Valley and
the Turtle Mountains area. This extension is based on 0.5km winds
of 40-45 kts continuing for these areas based upon the 17-18 UTC
HRRR well into the evening. Across the far west, the Wind Chill
Advisory remains unchanged through Wednesday morning. As the
Blizzard Warning expires this evening, some counties may need to
be added to the Wind Chill Advisory. As the arctic high builds
into the region on Wednesday, widespread single digit highs are
expected across western and central North Dakota.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 149 PM CST Tue Dec 6 2016
Dangerous wind chills Wednesday through Friday and the potential
for accumulating snow on Saturday highlight the extended forecast.
The 12 UTC global suites are in good agreement on arctic high
pressure across the Northern Plains Wednesday through Friday.
Dangerous wind chills are possible at least during the overnight
and morning hours each day across portions of western and central
North Dakota. Dependent on cloud cover, Thursday night into Friday
morning may be very cold with the arctic high centered over
western and central North Dakota with a large snowpack.
Thereafter, accumulating snow is favored for Saturday across the
area north of a surface low forecast to propagate across the
central plains. The arctic airmass may rebuild across the area
Sunday into next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 943 PM CST Tue Dec 6 2016
IFR visibilities at KJMS will continue through the evening and
into the overnight hours. Some improvement to MVFR visibilities
can be expected by early Wednesday morning. Elsewhere low VFR to
occasional MVFR ceilings will be the rule through the night and
into Wednesday morning. Occasional MVFR visibilities in blowing
snow can also be expected, especially at KMOT. Occasional MVFR
ceilings and visibilities can be expected through the day Tuesday
in gusty afternoon winds and snow showers.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until noon CST /11 AM MST/ Wednesday for
NDZ001-002-009-010-017>021-031>034-040>045.
Blizzard Warning until midnight CST tonight for NDZ003-011-047-
050.
Blizzard Warning until 6 AM CST Wednesday for NDZ004-005-012-013-
022-023-025-036-037-048-051.
&&
$$
UPDATE...TWH
AVIATION...TWH
Area Forecast Discussion
National Weather Service Denver/Boulder CO
811 PM MST Tue Dec 6 2016
.UPDATE...
Issued at 811 PM MST Tue Dec 6 2016
Snow has spread onto the Front Range, mainly west of Interstate
25. A couple of snow bands are stretching across the area with
heavier snowfall. Will make a couple of adjustments to the
forecast. First will be to trim snowfall amounts by an inch over
the eastern plains. The latest GFS, ECMWF and HRRR all show
precipitation amounts less than 0.15 of an inch. This would result
in less than 3 inches. An exception will be under snow bands
where an extra inch or two is possible. Also, increased snow
accumulation by about an inch over Boulder county where heavier
snow has started. Not a fan of the 00z NAM. It is not far enough
east with the current snow and doesn`t show any of the snow bands.
Also made minor changes to overnight lows to line up with current
trends.
UPDATE Issued at 605 PM MST Tue Dec 6 2016
Atmosphere along the Front Range continues to moisten from the
20 to 30 deg dewpoint spreads observed earlier this afternoon.
In addition KDEN and KCYS radars have detected an expanding area
of light precip...i.e. snowfall over and along the Front Range
especially within the past hour. The moistening is originating
from aloft with mid and high level moisture spreading in from Utah
in advance of the 700-500 mb trough axis. Recently updated the
weather and pop grids to delay measurable snowfall within the i-25
corridor until after 01z which appears to be working out. Also
delayed snowfall farther out on the plains by a couple of hours
even though radar is now indicating some banning out there. In
addition...the gusty southeasterly winds acrs eastern metro area
and points east should ease as they turn easterly with arrival of
the cold front presently slipping south through central
Weld...northern Morgan and Logan counties. At its present
speed...should see it in the metro area in the next hour or so.
That`s when snowfall should enhance along the I-25 corridor range
including the Denver metro area. Although the heavier snowfall not
expected until later tonight when the upstream jet enhanced
forcing arrives.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 154 PM MST Tue Dec 6 2016
Light radar echoes have blossomed over the mountains and northern
Front Range...foothills...and northern front range. Not much has
been reported at the ground...but the process has begun. I had
considered delaying the start of the mountain advisory...but snow
will begin impacting roads during the afternoon. For the lower
elevations...the Ruc13 shows snow starting in the metro area
around 3z...the HRRR around 07z...the Nam after 03z...the GFS
after 03z. Will mention mid evening as a starting time...this is
good news because the evening rush should not be severely
impacted. The morning rush is another story, as snow is expected
to fall through mid morning Wednesday and roads will likely become
snowpacked.
snow accumulations are another difficult forecast today...latest
SREF plume forecasts give a mean of 2-3 inches over much of
northeast Colorado...with barely an inch at Limon. In the Urban
Corridor the numbers were a bit higher. I was considering an
extension of the advisory to cover parts of northeast Colorado...but
these snow amounts in eastern Colorado were below criteria. snow
will begin to decrease across the area during the afternoon on
Wednesday.
Temperatures will be frigid tonight and tomorrow. With clouds the
mountain valleys will be warmer...but eastern Colorado will have
lows in the single digits tonight...and mid teens on Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 154 PM MST Tue Dec 6 2016
By Wednesday night subsidence will be moving in over the region
bringing clearing skies and snow to an end by late Wednesday.
Winds will be light and combined with clear skies bring overnight
temperatures below zero over the forecast area. Mountains could
see temperatures fall overnight to -20...especially in the
valleys.
On Thursday increasing NW flow aloft will bring a continual supply
of moisture to the mountains with some polar jet influence keeping
orographic snow possible. Temperatures will moderate on the plains
but with snow on the surface and some lingering cloud cover
expect temps to be slow to increase so kept highs lower then
guidance. by late Thursday the jet stream will drop south
bringing instability to the Northern Mountains and increase
snowfall intensity slightly. The strong westerly flow will create
downsloping off the foothills and keep the plains dry.
Temperatures on Thursday will continue to be below normal with
highs in the teens increasing back into the 40s by Friday.
Conveyer of moisture will continue to move into Colorado from the
NW as the jet moves south over the state by the weekend. This
will create increasing snow for the mountains with a slight chance
on the plains by Saturday evening with the passage of a cold
front late Saturday. The front will turn surface winds more
northerly...however, model guidance has just limited moisture for
the plains so do not expect much in the way of accumulation.
Temperatures for the weekend will drop once again but only into
upper 30s and lower 40s. winds will increase in the mountains with
the help of the upper jet with gusts up to 50 mph possible at
higher elevations. This will cause areas of blowing snow and
possible hazardous driving conditions for weekend travelers.
The weather pattern will remain active into the start of next week
with winds at lower elevations as the jet remains over the state.
Temperatures will average closer to normal by monday into Tuesday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 811 PM MST Tue Dec 6 2016
Snow has been slow to arrive at KDEN and KAPA. Light snow/flurries
should begin soon with heavier snow to start around 06z. Lowered
snowfall amounts a little at KDEN to KAPA with around 3 inches
expected. Low clouds with ceilings less than 2000 feet should hang
on through about 18z Wednesday with reduced visibility. Conditions
will slowly improve through the day, though ceilings are expected to
stay below 6000 feet.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon MST Wednesday for COZ031-
033>036-038>041.
&&
$$
UPDATE...Meier/Baker
SHORT TERM...RTG
LONG TERM...Bowen
AVIATION...Meier
Area Forecast Discussion
National Weather Service Columbia SC
1020 PM EST Tue Dec 6 2016
.SYNOPSIS...
Dry high pressure will briefly build across the forecast area for
Wednesday. Another cold front will cross the region Thursday
bringing much colder air for the end of the week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Winds out of the west/northwest through the night as an area of
low pressure moves off the Mid-Atlantic coast tonight. Plenty of
cloud cover remains over the region, and expect continued high
low-level moisture. Combine this with drier air moving in aloft,
along with overnight cooling, and the potential exists for significant
fog development. This is being shown by the latest hrrr, nam12,
and rap models late tonight into the morning hours. Best chance
for development early based on the models may be across the
western cwa, before spreading eastward towards morning. If this
occurs, and depending on the fog density, a dense fog advisory
may be needed. Followed the guidance consensus for the temperature
forecast.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Expect lingering fog and low cloudiness in the morning Wednesday.
Visibilities gradually improving, but some concern over lingering
cloud cover near an inverted trough setting up near the CSRA.
Otherwise, expect dry conditions Wednesday. Weak isentropic lift
near the boundary ahead of an approaching front could promote some
continued cloud cover Wednesday night, but no precipitation
expected.
Upper trough will swing from the central CONUS to the E CONUS
Thursday, ahead and south of which an upper impulse will ride
across the southern tier of states and across our region. A cold
front will move through our region Thursday. Models indicating
limited moisture with the system, with the most recent guidance
blend confining slight chance pop to the N FA. Behind the front,
cold dry polar high pressure will shift into the SE CONUS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The center of the polar high is expected to shift across the Ohio
Valley and towards the Central/Southern Appalachians Friday
night/Saturday morning. Some uncertainty as to how ideal the
radiational cooling conditions can get over our FA as the high
center may remain just to our north. However, if the high center
can get close enough, this air mass is cold and dry enough to
support undercutting guidance min temps for early Sat morning.
Will maintain min temps 20-25 across the FA. Daily record low for
Columbia for Dec 10th is 20, and for Augusta is 16. Latest GFS and
EC continue to indicate a front coming through Monday/Monday
night, with some weak isentropic lift light precip possibly
developing ahead of it Sunday/Sunday night. Some uncertainty with
the next system that could affect our region late Tuesday into
Wednesday. Used guidance blend.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
The complex low pressure system extending from the Ohio River
Valley to Southeast Coast will move northeast and be mainly off
the Mid-Atlantic Coast late tonight. The models show a weak
pressure gradient in the forecast area. Latest CAE VWP showing LLJ
slowly weakening. Expect continued high low- level moisture and
with the dry air aloft and nocturnal cooling, IFR/possible LIFR
ceilings and fog will likely continue through the overnight hours. Wind
should remain light Wednesday with a lingering inversion.
Improving ceilings and visibilities associated with some heating
may be slow to occur Wednesday.
EXTENDED AVIATION OUTLOOK...
A cold front with little moisture will move through the area
Thursday. Breezy conditions may be associated with the front.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
550 PM CST Tue Dec 6 2016
.DISCUSSION...
Updated for the 00Z Aviation Discussion.
&&
.AVIATION...
Not much change from the previous TAF set. Did slow the increase
in cloud coverage a few hours...with lower clouds beginning to
push south into VCT around 05Z...reaching ALI-CRP-LRD around 07Z.
Mostly MVFR CIGs overnight...however with -DZ possible...CIGs may
lower to IFR. Slight lifting in CIGs through the day...but should
maintain MVFR around 2000-2500 FT during the afternoon...along
with -RA possible. Winds will generally be light out of the north
becoming more east-northeast after 18Z.
&&
.PREVIOUS DISCUSSION... /Issued 356 PM CST Tue Dec 6 2016/
SHORT TERM (Tonight through Wednesday night)...
The front continues to advance through South Texas, south of a
Columbus to Uvalde line at 21Z, with post-frontal stratus a little
behind the boundary. Appears this cloud cover will reach the area
after the front moves through this evening. Went closer to the
HRRR with timing of cloud cover increase. Updated the TAFs to show
this adjusted timing also. Isentropic lift will gradually be on
the increase from Deep South Texas Wednesday morning. Will show
possibility of light drizzle over the Brush Country to the Coastal
Bend. Isentropic lift/warm air advection axis shifts toward the
coastal plains in the afternoon. But chances for measurable rain
look minimal, so will only show 10 percent PoP for now. With cloud
cover assisting with keeping shallow cool air mass in place, high
temperatures may struggle to reach 60 degrees over the northern
Brush Country. The front is expected to stall early Wednesday
morning just east of the offshore waters and move back toward the
coast as a warm front but still be over the Gulf waters through
Wednesday evening. Arctic air mass will be surging south toward
the area Wednesday night and reach the coastal waters before
daybreak Thursday. The models usually struggle with timing of
arctic air masses so would not be surprised if it arrives sooner.
With that in mind, kept the start of the Gale Watch for the Gulf
waters at 09Z Thursday. Low level warm air advection over the
coastal plains and coastal waters will lead to a chance for
showers with the frontal passage Wednesday night.
LONG TERM (Thursday through Tuesday)...
Post frontal winds will be very strong during the day on Thursday
with a 7 to 8 mb pressure gradient across the forecast area at its
peak. Strongest winds will occur in open marine waters where warm
SSTs will promote efficient mixing down of 30 to 40 knot winds.
Gusts as high as 30 to 40 knots will be possible for marine areas
with 30 to 40 mph gusts possible for much of South Texas.
Enough moisture will linger aloft that a developing weak upglide
flow around the 700mb level will linger a chance of showers behind
the front, mainly in the south. Expect a cold day with highs in the
50s. Rain chances should diminish Thursday night with a cold night
in store. Decreasing clouds in the north will allow temps to drop to
near freezing...currently have lows of around 34 degrees, but could
see a few locations colder than that. If clouds clear faster would
also expect colder temperatures. Expect mid to upper 30s farther
south with clouds lingering longer. Northerly winds weaken Friday,
but temperatures will stay cold. Locations north and west may not
make it out of the 40s. Wind will gradually shift around to the east
and southeast Saturday and Sunday. This will allow for a gradual
moderation of temperatures with a return to near or even slightly
above normal temperatures expected. Moisture will also increase
along the coast bringing a slight chance for showers back into the
forecast.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 50 68 53 54 39 / 0 10 30 30 20
Victoria 45 65 47 50 34 / 0 10 30 10 10
Laredo 49 65 49 52 37 / 10 10 10 50 20
Alice 48 66 50 53 37 / 10 10 20 40 20
Rockport 52 65 51 54 41 / 0 10 30 30 20
Cotulla 45 60 46 51 35 / 0 10 10 20 10
Kingsville 49 68 52 54 38 / 10 10 30 50 20
Navy Corpus 54 67 54 56 42 / 0 10 30 40 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Gale Watch from late Wednesday night through Thursday evening
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.
&&
$$
CB/85...AVIATION
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1100 PM EST Tue Dec 6 2016
.UPDATE...
Issued at 1100 PM EST TUE DEC 6 2016
Rain has exited eastern Kentucky as drier air filters in behind a
cold front. Stratus will slowly erode through the night as
west/northwest winds diminish to near and eventually below 5 mph.
UPDATE Issued at 653 PM EST TUE DEC 6 2016
Light rain continues to push east across far eastern Kentucky
ahead of an impending cold front. West/northwest wind gusts of
10-20 mph will continue this evening before diminishing as high
pressure inches closer. Should see upslope induced rain come to an
end by midnight as drier air advects in.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 300 PM EST TUE DEC 6 2016
Cool damp weather to continue throughout the afternoon and
evening hours today, although the ongoing rain is tapering off
quite a bit faster than previously forecast. The HRRR model has
the last of the rain out of eastern Kentucky by between 0 and 1Z
this evening. Based on the latest radar trends, and the HRRR data,
have decided to speed up precipitation evolution across eastern
Kentucky by several hours, with the last isolated showers or
patches of drizzle moving out of the area between 3 and 4Z. The
rain may actually end even faster than this, but did not feel
comfortable going completely dry as quickly as the HRRR is
currently suggesting. The latest model data has eastern Kentucky
experiencing a dry period of weather on Wednesday as the current
upper trough continues to move off well to our east. There could
be a brief period of light rain and snow showers Wednesday night
into early Thursday morning, as a second upper level low moves by
just to our south. At this time precipitation probabilities late
Wednesday into Thursday look be quite low, 15 to 24 percent on
average, so only isolated rain/snow showers are expected at this
time. With such a small chance of precipitation expected, decided
not to include any snowfall accumulations at this time.
Temperatures should be running slightly below normal tomorrow and
tomorrow night, with daytime highs on Wednesday in the 40s and
overnight lows ranging from the mid 20s to lower 30s. Tonights
lows should be at or slightly above normal due to the influence
of the expected widespread cloud cover. Tonights lows should be in
the low to mid 30s for most locations.
.LONG TERM...(Thursday through Tuesday)
Issued at 309 PM EST TUE DEC 6 2016
While not official by the calendar, winter will arrive on
Thursday as a very cold airmass filters into the region. Models
continue to back away from the precipitation potential on Thursday
as a weak wave forms on the polar front to our southeast, but too
far away to produce much precipitation this far west. Will
maintain a 20 PoP for our southeast counties, but that`s it.
Temperatures will likely not rise much on Thursday, remaining in
the mid 30s for most locations. Cold advection engages Thursday
night with a better upslope component to the winds developing and
continuing into the day on Friday. Models show sufficient moisture
in the -8c to -12c layer for snow flurries to develop, and I would
not be too surprised if we don`t eventually need to add some
isolated snow showers into the forecast for our higher terrain.
Whatever the case, Friday will be our coldest day since last
February with highs remaining below freezing for most locations.
Low temperatures Friday night are still a little tough to figure
out as despite the fact high pressure moves overhead, some mid and
high level cloudiness may disrupt prime radiational cooling
conditions.
Our weather pattern transitions quickly to southwest flow aloft
over the weekend as a shortwave traverses the Pacific Northwest
and northern Plains states. As a result, temperatures will
moderate out of the freezer to the mid 30s Saturday and mid to
upper 40s by Sunday. The shortwave will continue across the Great
Lakes and into New England into early next week forcing a surface
cold front through the region. Timing differences remain, but are
not as extreme as yesterday, and models appear to be settling on a
Sunday night frontal passage. Was able to nix PoPs for Saturday
night, and ramp them up Sunday into Sunday night. Will continue to
mention a rain/snow mix at onset Sunday morning over our northern
counties, but that is looking like a minimal concern with the bulk
of the precipitation not entering the area until Sunday afternoon
when it will fall as rain. This system moves through quickly on
Monday with decreasing PoPs and a brief cool down which may allow
some of the precip to end as snow or a rain/snow mix into Monday
night. High pressure is then progged to build in on Tuesday with
seasonable conditions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 653 PM EST TUE DEC 6 2016
Ceilings currently in the LIFR/IFR category will slowly improve
toward IFR/MVFR criteria this evening and tonight as rain exits
off to the east and drier air filters in behind a cold front. As
this occurs, west/northwest winds of near 10 knots with a few
gusts near 15 knots will take place before approaching high
pressure moves toward eastern Kentucky later on tonight. VFR
ceilings should return by mid Wednesday morning as mixing ensues
in tandem with aforementioned drier air advecting in. Winds will
continue veering northwesterly while decreasing below 5 knots
Wednesday afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GUSEMAN
SHORT TERM...AR
LONG TERM...ABE
AVIATION...GUSEMAN
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
849 PM CST Tue Dec 6 2016
.UPDATE...
The forecast was updated to account for lower overnight
temperatures. Some TTU mesonet sites have already reached their
forecast low this evening or were approaching it. Scattered clearing
of the high level cirrus and relatively light winds have allowed
temperatures to rapidly decrease this evening at some locations
more than others. Low level moisture will continue to increase
through the rest of the evening and overnight hours. Additionally,
low stratus is expected to move in early Wednesday morning.
However, these activities will likely be too late to greatly
affect the already low temperatures observed.
&&
.PREV DISCUSSION... /issued 549 PM CST Tue Dec 6 2016/
AVIATION...
Good low level moisture return this evening will spread stratus
northwestward, likely affecting KLBB and KPVW late tonight. IFR
conditions looking the most likely outcome. Veering of winds to
the west ahead of an arctic cold front should restore VFR
conditions by Wednesday afternoon.
PREV DISCUSSION... /issued 343 PM CST Tue Dec 6 2016/
SHORT TERM...
Colder weather has settled in across the area and we will see
another reinforcing surge of arctic air on Wednesday. Surface
high pressure ridge is centered to our NE and is moving away as
winds respond to low pressure across Colorado. Broad cyclonic flow
to continue across the southern Conus with strong jet and flow of
Pacific moisture keeping mid and high clouds over the region.
Focus late tonight turns toward prospect of low stratus and
freezing fog as NAM...HRRR and RAP all indicating areas of
advection fog developing as low level warm moist advection
commences above cold surface temps. Not expecting significant
precipitation early Wednesday as moisture is very shallow so left
out mention for now. Low stratus/fog likely to lift by mid to late
morning as westerly surface winds increase ahead of next cold
surge in the late morning to early afternoon. Would normally
expect this type of front to be well ahead of schedule...and that
may happen but given shallow nature of front and cyclonic zonal
flow aloft...model timing may be pretty close. We are currently
expecting front into northern zones by noon to 1 pm...through
Lubbock by 1-3 pm...and clearing the remainder of the Rolling
Plains and southern South Plains by 5 pm. Leaned toward the lower
end of MOS guidance given nature of this modified Cp airmass.
Highs occurring early...then temps falling quickly toward sunset.
James
LONG TERM...
Only change of concern to the inherited long term package was to
introduce non-measurable wintry precip late Wed night into early
Thu following tomorrow`s strong FROPA. Model soundings are
trending more moist in the post-frontal regime with decent
saturated depths progged along the frontal inversion. Coldest
temps within this saturation are at -10C or warmer at times, so
some ice nucleation/snowflake development is possible. However,
muted ascent and dry air advection should limit any of this to
just light freezing drizzle and flurries before the stratus erodes
from N-S Thu afternoon. On that note, latest MAV is very stubborn
in clearing out clouds during the day, hence its highs only in the
upper 20s for Lubbock. Feel lower 30s is a safe bet for now given
some clearing and very dry air advecting south, which will set the
stage for another bout of chilly lows Fri morning.
Largely zonal upper pattern through late week will keep the chilly
surface ridge progressive and allow a nice recovery in max temps
by Sat, before another cold front becomes dislodged by a shortwave
trough to our north. GFS is more bullish with this wave than the
ECMWF and therefore is about 12 hours faster with the front. Not
inclined to bite on any one solution yet, but have nudged temps
cooler on Sun - somewhere between the chilly GFS and unseasonably
mild ECMWF. Thereafter, an even more significant cold wave looks
to be materializing given a southward dislodging of the Polar
vortex progged through the Canadian Prairies, with bitterly cold
air (850mb temps of -20C or colder) possibly overspreading a large
chunk of the Great Plains Mon-Tue.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
01/07