Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/17
Area Forecast Discussion...Updated
National Weather Service Billings MT
845 PM MST Fri Mar 10 2017
.UPDATE...
Have cancelled the remaining zones in the Winter Weather Advisory.
While some scattered snow showers are possible across eastern
Montana and into the Dakotas, models are not showing any
additional significant accumulations. Much of the activity on the
radar from Forsyth down to Sheridan seems to be low to mid level
clouds with some virga. Surface observations and webcams were not
showing any precip.
The main concern overnigh remains some possible patchy fog. The
HRRR is hinting at some from Roundup and Billings eastward. The
SREF probabilities of visibility less than 3 miles is also
showing some increase chances, but only as high as around 50
percent. Have continued the patchy fog in the update. Given that
models continue to show a wind shift to the northeast overnight as
a weak front tries to push back in, this may also help to keep
enough mixing to limit the fog. Reimer
&&
.SHORT TERM...valid for Sat and Sun...
Right entrance quad to upper jet passing over our eastern zones
today. This has produced widespread precipitation ranging from
rain to snow and even freezing rain and sleet thanks to the warm
air hanging over the cold shallow air mass at the surface. This
continues to gradually slide southeast this evening and overnight.
So a decreasing trend in PoP`s remains reasonable through
tonight. There is a weak push of cold air again later tonight
which will prevent the cold air retreat and bring in some low
stratus and/or fog as far east as Billings late. Not sure how fog
may pan out, but included patchy fog across east and central zones
for now.
Saturday will be mostly dry and a little warmer across our CWA as
a brief weak ridge builds over our area. However, more short wave
energy moves out of Canada Saturday night into Sunday. Cold air
will still be in place across eastern two thirds of our CWA, at
least in the low lying areas and river valleys. Progged soundings
indicate a chance of freezing precipitation again, so will add a
mention of this for late Saturday night through about noon Sunday.
As for highlights...we cancelled most of the winter highlights in
the western zones earlier this morning. The winter storm warning
for the mountains is cancelled as heavy snow is no longer expected
with cross sections indicating dryer air moving into the mid
levels. The threat of additional weather impacts beyond roads
which are already slick in the east seems low, but some banding
may produce sudden change to conditions overnight. Therefore, we
have decided to leave the remaining advisories out for Custer,
Carter and Fallon counties. The evening shift will monitor these
for possible early cancellations. BT
.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...
Warmer but still active weather can be expected through the
extended period.
Though the northern Rockies will be underneath a ridge aloft on
Monday, the combination of moisture/pv spilling over the ridge and
a colder trof digging into the northern plains to our east, looks
to bring a period of snowfall along a baroclinic zone in our
eastern zones. Cannot rule out a few rain/snow showers to the
west, but best chance of pcpn (i.e. snow) will of course be east
of the SFC trof and in the colder air. Baker and Ekalaka will
struggle to rise above the lower 20s, and could pick up an inch or
two of snowfall. Locations along our western foothills could see
50 degrees with downslope winds. Quite a temperature spread from
west to east on Monday.
Ridge axis will shift east allowing for warm air to surge across
our lower elevations on Tuesday, signaling an end to the current
cool spell. We should see temps in the 40s/50s across the area,
but with additional Pacific moisture and energy there will again
be the risk of some showers. Models are in disagreement w/ the
timing of these showers, so have broadbrushed pops across Tuesday
and Tuesday night. Have also lowered temps just a bit as previous
model runs appeared drier/ridgier on Tuesday.
Confidence is higher for a warmer and dry day on Wednesday with
temps in the 50s to lower 60s.
Next Pacific trof will move inland and bring our next chance of
showers sometime Thursday and Thursday night. GFS is more dynamic
and shows a rain to wet snow transition, with 850mb temps falling
to around 0C, but the EC is weaker and not as cold. Will
compromise and raise pops these periods. Thursday could be a warm
pre-frontal day depending on the timing of the Pacific front. Lots
of model spread here.
Friday looks dry and cooler (but likely not cold) with some post-
frontal W-NW winds.
JKL
&&
.AVIATION...
MVFR/IFR ceilings will move into areas from KBIL S and E
overnight. There will also be areas of fog with visibilities in
the MVFR range. However, locally lower visibilities are possible.
VFR conditions are expected around KLVM. Areas of MVFR/IFR will
linger over the area Sat. morning, but most areas will see
improvement in the afternoon. There will be areas of obscuration
over the NE Bighorns into Sat. morning. The next system will
approach the area from the west Sat. evening, bringing scattered
snow showers to areas N and W of KBIL. Arthur
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 020/033 029/044 025/045 036/055 038/060 041/060 035/055
10/B 32/R 23/W 22/W 21/B 13/W 21/B
LVM 031/045 037/047 032/050 040/059 038/061 039/056 030/054
10/B 32/O 23/W 23/W 21/B 23/W 21/B
HDN 017/033 024/042 018/041 028/052 033/059 036/060 029/053
10/B 32/S 23/W 22/W 21/B 13/W 21/B
MLS 012/024 021/030 012/029 022/044 031/051 035/055 031/050
31/E 45/S 24/J 32/W 11/B 13/W 21/B
4BQ 017/031 024/040 016/035 023/049 032/058 035/060 030/053
41/B 34/S 14/J 32/W 20/B 13/W 21/B
BHK 010/024 017/026 006/022 015/039 026/048 032/055 030/047
52/J 46/S 16/J 42/J 10/B 13/W 21/B
SHR 028/040 031/047 024/047 032/058 034/062 037/063 033/057
40/B 23/O 23/W 22/W 21/B 13/W 31/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service State College PA
1017 PM EST Fri Mar 10 2017
.SYNOPSIS...
High pressure will build out of the Great Lakes today in the
wake of the departing storm system. Much colder air will follow
for the weekend.
A late-season winter storm could possibly affect the region
Tuesday into Wednesday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
High Res GOES R visuals show a cellular cumulus field advecting
SE under the cold pocket aloft. The RAP shows some modest CAPE
developing in this area of steep low-mid level lapse rates. As
a result we are seeing numerous snow showers and even some
locally heavier squalls develop and move SE into the Central
Mountains. The HRRR keeps this activity going through about 21Z
before it starts to wind things down quickly toward sunset. So
an additional ground whitening squall cannot be ruled out
through late afternoon.
The numerous breaks in the clouds have let the strong March
sunshine heat the pavement causing the earlier snow to melt
rapidly, except on grassy surfaces.
Colder air will continue to filter in behind the storm on an
increasingly blustery NW wind. The overnight will be mainly dry
over central and southern locations, with little more than a
passing flurry or brief snow shower. The best chance for
measurable precip will be over the usual higher elevation areas
from the Laurels northward. Lows in the teens will average
around 15 deg colder than normal, something we have not seen
much of this winter.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Saturday will see a mix of sun and clouds with a chance of a
passing snow shower or flurry, especially over the west and
north.
Highs in the teens north to around 30 in the SE will be 20-30
deg colder than normal. Gusty winds will drop wind chill values
into the 0 to -10F range.
Additional minor snow accumulations are likely across the
NW snowbelt due to persistent cold NW flow over the unfrozen
lakes.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
*Unseasonably cold weather pattern into Mid-March
*Late-winter heavy snow risk early next week
High pressure becomes the main synoptic feature driving sensible
wx early in the period, with snow showers and flurries tapering
off over NW PA by Monday. Temperatures remain unseasonably cold
with max/mins averaging 15 to 25 degrees below early March
climo Sat night-Sunday night.
A significant late-winter storm system is expected to develop
off the Mid Atlantic Coast early next week and bring the
potential for late season heavy snow to much of Central PA.
Timing at this point would start pcpn Monday evening with the
heaviest snow from Monday night into the daytime hours Tuesday.
Assuming a storm track as currently forecast, heavy snow
amounts of 6+ inches are possible across a broad area with
double-digit snow accumulations not out of the question.
However, there are still several factors that will make snowfall
forecasts difficult even at shorter ranges including time of
day (snow accumulation at night vs. day) shifts in the storm
track and location of rain/snow line. The heavy snow risk will
continue to be highlighted in the HWO.
A reinforcing surge of cold air will follow behind the storm
with snow showers likely persisting through mid week. It should
take until next weekend for temperatures to get back to more
typical values for Mid-March.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Snow showers continue to slowly diminish with loss of daytime
heating, yet satellite continues to show broken, cellular
streamers of clouds and snow showers coming off the lake in the
brisk northwest flow. Overall, snow showers should continue to
diminish overnight, but still produce periods of MVFR to
occasional IFR conditions across the western and northern
mountains.
Gusty northwest winds have also begun to slacken a bit, but
should remain rather brisk overnight, with sustained winds in
the 12 to 15 knot range. High gusts are expected to subside
after 05z-07z, but pick up again during the mid morning
Saturday.
Saturday will feature widespread VFR conditions, with the chance
of brief reductions and scattered/isolated snow showers, mainly
over the higher elevations of the west.
Outlook...
Sun...Mainly VFR. OCNL MVFR with scattered snow showers NW.
Mon...No sig wx.
Mon Night-Tue...Widespread MVFR/IFR with snow/rain.
Wed...Windy and mainly VFR, with residual MVFR conditions and
snow showers.
&&
.CLIMATE...
Low Maximum Temperature Records for Saturday, March 11th:
MDT27 in 1934
IPT 26 in 1934
AOO26 in 1998
BFD13 in 1969
STC21 in 1992/1969
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...La Corte
LONG TERM...Steinbugl
AVIATION...Jung
CLIMATE...La Corte
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
948 PM CST Fri Mar 10 2017
.Update...
Issued at 946 PM CST FRI MAR 10 2017
Late afternoon and evening model runs have continued the trend of
advertising snow, but also of under cutting it with dry air from
the east. Given the time of day of the snow arrival --daylight
hours-- expectations have always been that models where over doing
snow totals a bit, but now models seem to be catching on as 18Z
and 00Z models from the NAM and GFS have started to pull back on
snow amounts, and the high resolutions models like the HRRR are
looking even stinger with the snow. As a result, thoughts are that
the onset of the snow might be a bit later in the morning owing
to the need to saturate a very dry surface layer, but we are still
expecting a bit of mid-level forcing in the late morning to
afternoon hours roughly along the north side of the Missouri River
which should be sufficient to generate some snow bands. Have
trimmed snow totals to below an inch in areas outside where the
mid-level frontogenic forcing is currently advertised to set up.
This means there might not be much snow --trace to half an inch--
along the Iowa border, or in areas south of Highway 50.
Additionally, late in the day there appears to be enough mid-level
warm air advection to warrant some expectation that liquid rain
showers may develop from any snow showers still occurring,
especially in areas of eastern Kansas and west central Missouri.
Otherwise, cold overnight temperatures still look sufficient to
warrant the Freeze Warning for the weekend.
&&
.Discussion...
Issued at 404 PM CST FRI MAR 10 2017
...Winter to make a brief return this weekend...
Northwest flow prevailing over the region with the next shortwave
of interest seen over the Pacific Northwest this afternoon. Fcst
models in excellent agreement that this feature will track out of
the Northern Rockies overnight, before diving through the Central
Rockies on Saturday. As this feature nears, a tightening midlevel
thermal gradient will lead to a region of strengthening
frontogenesis by Saturday morning across the Lower Missouri
Valley, with all indications suggesting this max will be oriented
in a northwest to southeast fashion directly over the forecast
area. As of this afternoon, there still remains a minor placement
issues with respect to where the axis will set up, however the
consensus seems to indicate that increased PVA in advance of this
wave will begin interacting with the increased frontogenetical
forcing to lead to quick burst of precip from Saturday morning
through mid/late afternoon.
Overall, system will have a limited moisture supply to work with
as evidenced by dewpoint depressions on the order of 30 degrees
this afternoon. As a result, a fair amount of time will be needed
to saturate the lower atmospheric column for precipitation to
reach the ground. Based on latest guidance, precip should begin
moving in between 10-13z across much of the area, however it may
take to the end of that window based on the amount of dry air
depicted on latest fcst soundings. That said, low QPF coupled
with fast system movement, poor timing (daylight hours), and warm
ground temperatures should hold accumulations to the 1-2"
range across much of the area, with localized 1-3" possible if a
decent band is actually able to establish itself. Much of this
accumulation may be confined to grassy and elevated surfaces as
road temps remain warm. Based on this, along with collaboration
with adjacent offices, have elected not to hoist any winter
headlines at this time.
Dry weather to return on Sunday along with warming temperatures
as the next feature of interest approaches in continued northwest
flow aloft. Models overall have come in warmer with this second
system, and based on latest thermal profiles, much of the
precipitation will likely fall in the form of rain across the
area. Again, not anticipating the need for any headlines unless
something drastic changes between now and then. Despite the fact
that dynamics appear better for this secondary system, too much
warm air looks to be in place ahead of it to have significant
winter impacts at the present time.
Moving beyond this, temperatures look to moderate early next week
as upper riding in place this weekend over the western U.S.
begins sliding east with time. Next strong storm system looks to
slide just to our north Thursday/Friday, not before 850 temps of
close to 16C overspread the area Thursday night. At least winter
tried to make a brief return...
&&
.Aviation...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 535 PM CST FRI MAR 10 2017
VFR conditions will prevail well through midnight, and likely for
the entire overnight period. Snow showers will start moving in
around sunrise, but with the dry east wind at the surface it will
likely take awhile for snow to reach the ground and accumulate.
Expect the late morning to early afternoon band of moderate snow
at the terminals with the snow tapering off by the mid to late
afternoon hours.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Freeze Warning from 6 PM CST Saturday to 1 PM CDT Sunday for
KSZ057-060-103>105.
MO...Freeze Warning from 6 PM CST Saturday to 1 PM CDT Sunday for
MOZ028-043-053-054.
Freeze Warning until 1 PM CDT Sunday for MOZ029>032-037>040-
044>046.
&&
$$
Update...Cutter
Discussion...32
Aviation...Cutter
Area Forecast Discussion
National Weather Service Grand Forks ND
925 PM CST Fri Mar 10 2017
.UPDATE...
Issued at 925 PM CST Fri Mar 10 2017
Temps continue to fall below zero near the Canadian border while
the southern CWA remains near 10 above. Temps under the sfc ridge
in the north should drop to near 10 below and although borderline,
get to wind chill criteria. Will maintain the headlines.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 224 PM CST Fri Mar 10 2017
Forecast challenges for short term period will focus on wind chill
headlines across the north and light snow potential across
central ND. Northerly sfc flow to continue throughout the night
and will combine with overnight lows in the 10 below to 15 below
range north of Hwy 2 to bring wind chill advisory range Apparent
Ts back to the far northern tier of zones. Coldest Apparent Ts in
the 06Z to 13Z timeframe but will go through 14Z as latest grid
update keeps LOW County in a bit longer. Advisory to be issued
with aftn forecast pkg.
WV imagery indicates an upper wave currently extending from SW
Sask through NW Montana. 12Z GFS 1.5 PV surface pressure
advection aligns nicely with wave depicted on WV imagery. 1.5 PV
surface weakens eastern extent of wave as it moves through ND
tonight while strengthening it over central ND down into SD.
Furthermore, 285K isentropic sfc shows decent lift across central
ND that is cut off along and east of about a Rugby to Fingal line,
where isentropic sfc winds parallel isobars, thus keeping best
ascent west of our CWA. This combined with continuous NE flow and
a very dry airmass to overcome, prefer HRRR guidance that keeps
QPF mainly west of CWA. Blended solutions do bring low POPs into
western counties however very little QPF, generally less than 0.5
inches snow accum in the swrn zones. This solution looks very
reasonable and therefore using CONSSHORT POPs, SuperBlend QPF but
would not be surprised to have only flurries across the western
edges of those counties. Daytime highs Saturday similar to
today...ranging from the single digits to mid teens above zero.
.LONG TERM...(Saturday night through Friday)
Issued at 224 PM CST Fri Mar 10 2017
Models are showing a short wave diving from northwest to southeast
Sunday into Sunday night, glancing our far southern FA. Yesterday
this wave was further west and now today it has shifted a little
further to the east again. Models are showing precipitable water
values rising to a little above a quarter inch and they also show
mesoscale and synoptic lift occurring together for a time. On the
flip side, the area has been stuck in a colder and drier regime. By
Sunday and Sunday night, the sfc ridge is further east, but there is
still a drier east to northeast sfc wind component.
After running snow amounts from the new QPF forecasts, areas along
the ND/SD border have increased slightly from the previous forecast.
This gives areas along the ND/SD border 4 to 5 inches, and possibly
up to 6 inches of snow. This being only the second model run showing
much of anything across the far southern FA, and the fact that it
could take a while to overcome the dry air, will lean more toward
the 3 to 5 inch totals being more accurate. Also the GEFS plumes for
this area are still only showing 3 to 4 inches of snow. Therefore,
at this time, do not plan on a winter storm watch for the southern
FA Sunday into Sunday night.
After this system moves off, most of the rest of the week is looking
pretty quiet. The 500mb flow remains mainly from the northwest, and
temperatures will stay on the cooler side until Wednesday. By
Wednesday, the 500mb ridge builds in with 850mb temps rising quite
nicely. This results in a return to above normal temps again for Wed
through Fri. Guidance brought in some pcpn chances again by Thursday
night into Friday, but confidence a little lower by then.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 639 PM CST Fri Mar 10 2017
Increasing high and in the west, mid level clouds throughout the
period. Conditions will remain VFR at all TAF sites. North to
northeast winds will stay below 12 kts.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Wind Chill Advisory until 8 AM CST Saturday for NDZ006>008.
MN...Wind Chill Advisory until 8 AM CST Saturday for MNZ004>006.
&&
$$
UPDATE...JR
SHORT TERM...Speicher
LONG TERM...Godon
AVIATION...JR
Area Forecast Discussion
National Weather Service Green Bay WI
457 PM CST Fri Mar 10 2017
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Saturday
Issued at 212 PM CST Fri Mar 10 2017
The latest rap analysis and satellite/radar imagery show arctic high
pressure entrenched from central Canada into the central Mississippi
Valley early this afternoon. Northwest winds continue to generate
bands of lake effect clouds and snow showers into far north-central
WI. Some retreat of the clouds/snow showers should continue through
the rest of the afternoon. Looking out west, clouds are spilling
across the northern Plains on the leading edge of mid-level warm
advection. With a very dry arctic high in place, forecast concerns
revolve mainly around cloud cover and temperatures.
Arctic high pressure will continue to dominate our weather tonight
and Saturday. Mid and high clouds will invade from the west tonight
on the periphery of a clipper system that is projected to slide
southeast over the northern Plains. After lake effect streamers
retreat to the north, a slight veering of the low levels winds may
cause these streamers to return southward late tonight into Saturday
morning over northern WI. A few light showers cannot be rule out
there. With higher amounts of mid and high clouds to go along with
a breezy northwest wind, remained conservative with low temps and
wind chills. Looks like a few hours of wind chill indices from 15
to 20 below will be possible early Saturday morning over north-
central WI. Highs on Saturday will be warmer that today and will
range from the mid teens north to mid 20s south.
.LONG TERM...Saturday Night Through Friday
Issued at 212 PM CST Fri Mar 10 2017
Saturday night into Sunday morning will continue to have a few
chances of snow showers along the far northern parts of Wisconsin.
Temperatures will remain well below normal through this period as
well.
Attention then turns to the clipper system expected for Sunday
night through Monday. Uncertainty of the exact track for this
system continues with the ECMWF taking a more northerly route and
bringing in higher QPF than the NAM and GFS models. Snow ratios
are expected to lower along the lake and towards the southern
parts of the region in the afternoon as warming along the
shoreline from easterly flow is anticipated. Easterly onshore
winds could also bring some additional lake effect enhancement for
far eastern Wisconsin during the afternoon on Monday. With the
majority of the available moisture sitting to the south of the
area, snow totals around 2 to 4 inches are expected for the Fox
Valley, with around an inch in far northern Wisconsin. Additional
accumulation is then possible overnight into Tuesday morning
before the upper level trough moves out, although this timing
still has inconsistent signals between models as well.
Once this system does exit, an upper level ridge will keep
northwesterly flow in place with primarily dry conditions through
Thursday. Models have begun hinting at the next clipper system for
Thursday night into Friday morning with a fast moving upper level
shortwave. After the cooler start, temperatures will gradually
warm until we get near normal by the end of next week.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 457 PM CST Fri Mar 10 2017
VFR conditions and winds at or below 10 knots are expected during
the TAF period as high pressure builds in across the western Great
Lakes. The exception will be Vilas County where light lake effect
snow showers may return late tonight into Saturday morning.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Uhlmann
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Houston/Galveston TX
917 PM CST Fri Mar 10 2017
.UPDATE...
A cold front was draped just along the northern borders of Houston
and Trinity counties at 9:00 PM. Showers and thunderstorms were
still affect locations just south of the front across portions of
Houston, Trinity and Polk counties. Latest high resolution models
all show this area of rain diminishing later this evening or
during the early overnight hours. An area of rainfall over the
lower Texas coastal areas associated with an upper level low
pressure trough is then still expected to slowly move northward
overnight tonight.
Tweaked the rain chances mainly for the northern half of the area
for the remainder of this evening and then area wide overnight
tonight.
40
&&
.PREV DISCUSSION... /ISSUED 604 PM CST Fri Mar 10 2017/
AVIATION.../00Z TAF/
Radar continues to show mainly isolated TSRA across much of SE
Texas. Storms should be dissipating over the next hour or two with
some shower activity possible afterward. Will be watching storms
closely near KIAH for the next hour or two. We may need to amend
for TSRA at the terminal but radar trends should keep it within
the vicinity only. Same can be said for storms near KUTS/KCXO.
Ceilings are mainly VFR but except for along the coast with
higher moisture and sea fog for KGLS. Ceilings should drop to MVFR
and perhaps IFR although SREF ceiling probabilities are not all
that high for IFR ceilings for the area. IFR most likely for
KCLL/KUTS/KCXO for the morning hours. Ceilings will be slow to
improve tomorrow as weak upper low over the lower Texas coast will
slowly move across the area. Widespread SHRA/TSRA are expected
late morning through the afternoon. Based timing on GFS and WRF-
ARW trends. HRRR seems on track for near term trends. Beyond 00Z
SUN look for cold front to approach the area. It should begin to
push through around 06Z Sunday.
Overpeck
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 62 74 48 59 46 / 50 60 60 10 10
Houston (IAH) 63 73 54 61 49 / 40 70 70 10 0
Galveston (GLS) 65 72 58 63 56 / 50 70 80 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...40
Aviation/Marine...39
Area Forecast Discussion
National Weather Service Lubbock TX
528 PM CST Fri Mar 10 2017
.AVIATION...
Cigs expected to raise for a few hours at CDS before more moisture
streams in tonight and at least MVFR conditions returns. PVW and
LBB have enjoyed VFR most of the day, but the cloud line is slowly
retreating and MVFR is expected to set in around 6Z. With calmer
winds tonight, some fog along with the low clouds is possible
early morning. This has been touched upon in the package and will
be honed in further for next issuance.
&&
.PREV DISCUSSION... /issued 315 PM CST Fri Mar 10 2017/
SHORT TERM...
Overall chances for precipitation look increasingly poor with a
little wrench thrown in with the latest model runs as well.
Isentropic upglide will further increase tonight with low stratus
moving back into the region. However, this lift will not likely
translate to measurable precipitation during the overnight and
morning hours. Moisture will be fairly shallow on the caprock with
much deeper low level moisture north and east of the region in the
eastern Texas Panhandle and in Oklahoma. Furthermore, a good portion
of the isentropic lift over West Texas will be above this shallow
moisture layer. Increased low level moisture and the cloud cover
will keep temperatures mild again overnight.
A very weak short wave at 500mb will move over the region tomorrow
and combined with a strong cold front may develop convection.
Cooling temperatures at 500mb will lead to very steep lapse rates
spreading over the area. Models prog mid level lapse rates between 8
to 9 C/km. However, much of the area will be strongly capped with
the frontal forcing very unlikely to break the cap. The exception to
this will be across the southwestern South Plains where clearing out
will allow enough heating to erode the cap. The latest NAM, NSSL
WRF, TTU WRF, and experimental HRRR pick up on this solution and we
have adjusted the forecast to reflect these trends. Somewhat similar
sky conditions tomorrow will create another strong temperature
gradient with 70s in the southwestern South Plains and 50s in the
southeastern Texas Panhandle.
LONG TERM...
Any storm chances lingering into Friday evening (and favoring the
southern Rolling Plains) will quickly shift south of the CWA along
with the frontal forcing and minor disturbance aloft. Cool surface
ridging will follow the front with highs on Sunday mostly in the
60s. The far eastern zones, closer to the center of the departing
surface ridge may not make it out of the 50s. In addition, gusty
southerly breezes will develop during the afternoon, particularly up
on the Caprock, as the pressure gradient between the ridge and
surface low over southeast Colorado tightens locally. The developing
low will occur in response to a quick moving shortwave trough diving
across the northern and central High Plains. A dry cold front will
follow the disturbance, sweeping through the South Plains region
early Monday. This FROPA will provide a brief period of breezy
northerly winds by little to no cooling, with near average
temperatures expected. Return flow on Tuesday should spur a modest
warming trend, though a backdoor front (in response to a closed low
sinking through the Great Lakes region) may knock temperatures back
several degrees on Wednesday, particularly off the Caprock. Another
round of return flow and warmer temperatures will follow Thursday
before the next cold front Friday or Friday night. Moisture will
gradually improve mid to late week before the end of week FROPA, and
we could perhaps see a few showers in the region Wednesday and/or
Thursday, but without any obvious upper support chances are too low
to include explicitly in the forecast at this point. Overall it
looks like a rather benign stretch of weather with your typical
temperature ups and downs for this time of year.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/74
Area Forecast Discussion
National Weather Service Nashville TN
931 PM CST Fri Mar 10 2017
.DISCUSSION...
Cold night still on tap but mid clouds are coming in later
tonight...and wind speeds are not likely to drop totally off
overnight. Will continue freeze warning as it is still
largely expected to be at or just below.
Models still in tune with quick winter event tomorrow night.
Better overrunning and energy seems to shift more south...
with the southern plateau seemingly best area for higher
snow amount potential.
&&
.AVIATION...
00Z TAF DISCUSSION.
Clouds on the increase tonight, mainly high clouds this evening,
but thickening and lowering will take place thereafter. Hrrr
spreads some light sleet and light snow southeastward after
midnight but most of this wont reach the ground and will be patchy
in coverage. Lower level dynamics pick up a little more during the
day on Saturday. Freezing levels and the max temp up through 500
mb layer does support light snow, with some sleet initially.
Coverage will be patchy and will only include a prob 30 later in
the taf pd. Cigs and vsbys for the most part will remain aoa 3kft
and aoa 4sm, respectively.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 31 42 27 48 32 / 10 30 60 10 10
Clarksville 29 39 25 46 30 / 10 40 60 0 10
Crossville 27 41 25 45 29 / 0 20 70 10 0
Columbia 30 44 27 48 32 / 0 30 70 10 10
Lawrenceburg 30 46 27 49 31 / 0 30 70 10 10
Waverly 31 41 26 47 31 / 10 40 60 0 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 8 AM CST Saturday FOR Bedford-Cannon-
Cheatham-Clay-Coffee-Cumberland-Davidson-De Kalb-Dickson-
Fentress-Giles-Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-
Lewis-Macon-Marshall-Maury-Montgomery-Overton-Perry-Pickett-
Putnam-Robertson-Rutherford-Smith-Stewart-Sumner-Trousdale-Van
Buren-Warren-Wayne-White-Williamson-Wilson.
&&
$$
DISCUSSION......01/Boyd
AVIATION........01/Boyd
Area Forecast Discussion
National Weather Service San Diego CA
1250 PM PST Fri Mar 10 2017
.SYNOPSIS...
High pressure aloft anchored over the Southwest will bring
unseasonably warm weather through next week. A shallow marine layer
may bring areas of night and morning fog to the coastal areas this
weekend.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
High pressure aloft over the Southwest will be the dominate weather
feature through next week. Small disturbances will flatten the ridge
at times, but the overall pattern shows an extended period of
unseasonably warm weather through the weekend of March 18-19th.
Today`s cirrus shield is associated with a weak shortwave that will
trek across the southern Great Basin tonight and Saturday. The
clouds were thick enough over the northern areas to limit solar
heating and keep temperatures a couple degrees lower than yesterday.
Farther south over San Diego County the cirrus deck was thinner in
the morning, and temperatures were the same or a little higher than
yesterday before the thicker clouds moved in. Rancho Bernardo hit 85
(same as Thursday) at 11:02 AM, then the clouds rolled in and the
temperature fell to 78 at 12:30 PM.
The afternoon visible satellite showed an area of low clouds (or
perhaps a fog bank) 80 miles west of northern Baja. The marine layer
will remain shallow through Sunday morning, probably less than 300
feet. The BUFKIT soundings show saturation in the lowest 300 feet
both late tonight/Saturday morning, and again Saturday night/Sunday
morning, so some coastal communities may see patchy dense fog at
times. The HRRR model doesn`t show this happening tonight, but it`s
possible. The chances will be a little greater Saturday night into
Sunday morning. If the fog does reach the coast, the marine layer
will remain too shallow for it to extend inland more than a mile or
two.
Saturday will be another very warm day with highs 10-20 degrees
above average except near the coast due to the shallow marine layer.
Sunday and Monday will be even hotter as a 584 dm high builds over
the Southwest. Model guidance usually underperforms in these highly
anomalous events, so max temps have been adjusted upward a couple
degrees in most areas. Highs will be 15-25 degrees above average
during this time. The hot spots will be in the inland valleys where
weak offshore flow and downslope warming will send highs into the
middle and possibly upper 90s in the Inland Empire on Monday. Record
highs are possible then.
Model solutions diverge Tuesday and Wednesday. The ECMWF and
Canadian models keep a strong 584 dm ridge over the Southwest. In
contrast, the GFS fcsts a weak 576 dm trough moving across northern
Baja. That 80 dm height spread is significant, and is a difference
of 4-7 degrees in max temps. Will continue to weight the forecast
more closely to the ECMWF and Canadian solutions.
Thursday through Saturday: All the models project a ridge over the
Southwest for more unseasonably warm weather and much above average
temperatures. This early, long duration warm spell will elevate the
risk of heat related illnesses since most of us are not yet
acclimated to these "summer" temperatures. Plan and prepare
accordingly to keep cool and prevent dehydration and if outdoors for
an extended period of time.
&&
.AVIATION...
102030Z...Patchy dense fog could affect the coastal TAF sites late
tonight into early Saturday morning, although forecaster confidence
is low. Otherwise...FEW/SCT clouds at/above 20000 ft MSL will
continue through Saturday.
&&
.MARINE...
Areas of fog could form over the coastal waters late tonight and
into Saturday morning, with a little better chance of fog
development for Saturday night and Sunday morning. Otherwise, no
hazardous marine weather is expected through Wednesday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
PUBLIC...Moede
AVIATION/MARINE...PG