Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/18/17
Area Forecast Discussion...Updated
National Weather Service Billings MT
727 PM MDT Fri Mar 17 2017
.UPDATE...
Sent out an early update to reflect some virga and isolated
showers moving into our CWA from the west. Added these mainly over
the Belts and Snowy Mtns. Lower elevations exhibiting pretty wide
dewpoint depressions, so will be hard to measure on the plains.
Still looks warm with record highs likely tomorrow. Overnight
temps may stay milder than previously anticipated, so nudged
overnight lows up a bit in some areas. BT
&&
.SHORT TERM...valid for Sat and Sun...
Approaching upper ridge seen on water vapor will move over the
region tonight through Saturday. Models continued to show some
high elevation moisture over the SW mountains this evening, so
kept some low PoPs in this area. Otherwise, it will be dry through
Saturday. KBHK has been slow to lose the stratus this afternoon,
but visible satellite was showing decreasing clouds, so KBHK
should become mainly clear. RAP and GFS showed moisture developing
in the boundary layer late tonight over KBHK so have added patchy
fog to Fallon County into Sat. morning. Just some mid and high
clouds are expected over the area on Saturday. Deep mixing will
combine with strong downsloping to send temperatures well into the
70s and lower 80s. Expect the four climate stations to exceed
record highs and have highlighted this in the forecast. Mixing
will allow strong winds aloft to reach the surface W of KBIL
around locations like KLVM and Big Timber, so have increased winds
in these areas.
A tight pressure gradient will persist in the western zones Sat.
evening ahead of an approaching cold front, and gusty winds will
continue in the W. Models had the front reaching the eastern
zones by 12Z Sunday under a fast WSW flow. Jet energy N of the
area will bring some lift to the area along with the front.
Moisture will be limited to over and near the western mountains
through 06Z Sun., with limited moisture spreading E through 12Z.
Thus had slight chance PoPs over the far W through 06Z, and higher
PoPs over the W late Sat. night behind the front. Any snowfall
will be limited to the mountains due to the warm airmass.
WSW flow aloft will become W during Sunday. There will be
scattered showers across the area, and the focus for higher PoPs
will gradually shift S as the front slowly moves S through Sun.
night. Low-Level flow will shift E and favor upslope areas in the
foothills as well. It will be breezy and cooler behind the front
on Sunday with highs in the 50s. Expect a mix of rain and snow
showers Sun. night as temperatures fall into the lower 30s/upper
20s. Arthur
.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...
Monday looks like the chilliest day of the extended period with
temps expected to remain in the 40s, courtesy of a Canadian
surface ridge settled in east of the mountains. Moisture
overrunning baroclinic zone across our south into WY will keep a
chance of precipitation going on Monday, especially across our
southern foothills where some wet snowfall is possible with 850mb
temps near 0C. Mid level warm front will lift north allowing for a
chance of light precipitation across the lower elevations Monday
night into Tuesday, but there remains model uncertainty here with
regard to low level dry air and QPF. Overall, there is confidence
in lowering temps a bit on Monday and raising pops Monday into
Tuesday.
Building upper ridge should bring a brief period of dry wx Tuesday
afternoon into Tuesday night. Ridge axis will slide east opening
the door to shortwave energy from the great basin and our next
chance of showers by late Tuesday night and Wednesday. A stronger
trof is expected to move thru the central Rockies by Thursday in
this evolving progressive pattern. Model spread remains high
Thursday, with the 12Z GFS staying south of our cwa and mostly
dry, while the 00Z EC is further north and wet for us. Will keep
pops broadbrushed Wednesday night through Thursday night to cover
this period, and will need to monitor model trends. However you
slice it, without a surge of Canadian air, lower elevation temps
Wednesday to Friday look sufficiently warm to keep p-type as rain,
with high temps mostly in the 50s to lower 60s (Wednesday
probably the warmest day). Expect some high elevation snow with
each of the shortwaves next week.
JKL
&&
.AVIATION...
There is a slight risk of fog at KBHK late tonight and early
Saturday. Otherwise, VFR flight conditions will prevail through
tomorrow as high pressure aloft dominates the region. SW winds
will increase at KLVM, with gusts to 35 kts by late tonight and 45
kts by Saturday afternoon. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 040/077 045/057 032/046 032/056 039/062 038/056 036/059
00/B 14/W 41/E 22/W 22/W 33/W 21/B
LVM 042/074 043/057 031/047 032/058 039/059 035/054 032/057
00/N 35/W 43/O 32/W 23/W 33/W 32/W
HDN 036/082 043/057 030/049 030/056 034/062 034/056 033/059
00/B 14/W 41/E 22/W 22/W 23/W 21/B
MLS 035/078 043/057 031/049 031/051 035/059 035/056 032/055
00/U 13/W 10/B 12/W 21/B 22/W 21/B
4BQ 034/082 043/057 031/048 029/053 033/062 034/055 032/057
00/U 04/W 42/R 32/W 21/B 23/W 31/B
BHK 029/069 040/054 028/047 025/045 030/057 033/053 030/053
00/U 03/W 10/B 12/J 31/N 23/W 21/B
SHR 036/079 042/058 031/047 030/056 036/063 034/054 032/057
00/U 04/W 33/O 32/W 22/W 33/W 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service State College PA
1202 AM EDT Sat Mar 18 2017
.SYNOPSIS...
A complex frontal system will bring a light wintry mix into the
area overnight. High pressure returns for the end of the
weekend. Temperatures will briefly moderate into early next week
before trending colder Wednesday into Thursday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A disorganized area of light snow is working across the far
southern part of the CWA, pretty much in line with the HRRR
timing and coverage. This is the leading edge of the warm
advection associated with the approach of a complex frontal
system.
The parent upper low is the driver for this system and it is
progged to dive SE out of the upper Gr Lakes right over PA
during the afternoon. The occluded front is made to more or
less fall apart in favor of a new low that is forecast to
develop along the warm front over VA tomorrow afternoon, moving
off the coast tomorrow night.
Warm air will continue to move in aloft over the next 6-10
hours while cold air remains locked in the low levels.
Temperatures in the low levels will be rather marginal after a
mainly sunny day today, but it is very dry so we have been and
will continue to see some measure of evaporational cooling as
precip overspreads the area. NCAR ensemble shows a low
probability of light freezing rain or freezing drizzle, but our
advisories are triggered with a trace or more of ice so we
issued the advisory to cover the potential for light icing to
develop as the night progresses. Over the far north temps aloft
actually stay cold enough for all snow, but forecast soundings
show the moisture packed in the very low levels making freezing
drizzle the most likely precip type.
Overall QPF is expected to be only a tenth or two, so probably
just enough of a wintry mix to make things slippery but not
amount to much in the end.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
The main sfc low does dip into the Lower Lakes Sat morning, and
then the low transfers to the Mid-Atlantic coastal plain and
continues east. The temps do mild-up enough to make a transition
to all rain for much of the area - starting in the SW and along
the MD border early tonight. This transition will push to the
NE during the second half of the night. By morning, only the NE
half of the area will be cold enough for all snow or a snow/FZRA
mix. Mins tonight will be around freezing in the south and in
the u20s in the north. Temps will rise into the m30s N and l40s
in the south. Little chance for sun exists on Sat, but the March
sun is usually very good at doing some melting even if
something frozen does fall overnight/Sat morning.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Upper low over northwest PA drops southeast to Delaware Coast by
morning. Cyclonic flow with the low followed by northernly flow
across the lakes and a weak short-wave dropping through will
lead to scattered rain and snow showers Sunday. Sunday night
into Monday short-wave ridge aloft builds in bringing fair
weather and moderating temperatures some.
A weak cold front drops southeast into Central PA around
midnight Monday night and to the coast by sunrise. ECMWF has a
stronger low develop on this front down in KY moving east to NC
which steals moisture and POPs from PA. GFS does not have this.
POPs will be blended using ensemble blends. Temps will be
cooling Monday behind this front with reinforcing arctic air
moving down. These waves of cold air continue through Wednesday
and combined with cyclonic flow aloft and a jet max some sw-
possible across the northern tier of PA.
Strong hi center builds into Michigan and Ohio late Wednesday
slides into Central PA by Thursday morning and to the coast by
evening. ECMWF is a little slower with movement of high, but
this will bring a fair and dry day Thursday.
Warm advection moves in by Friday ahead of the next rigorous
system. Increasing Thursday night and probabilities for
precipitation increasing Friday. Chance rain Lower Susq Valley
with rain or snow elsewhere. Snow mix will hold on longest
northeast zones.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
A warm front approaching from the Ohio Valley will spread
lowering CIGs and light precip across central Pa overnight.
Current model data indicates IFR CIGs will become likely at
JST/AOO/UNV/BFD between 06Z-09Z, with MVFR CIGs becoming likely
at IPT/MDT/LNS during the same time period. In addition, light
snow is likely to reduce visibilities at times late this evening
at JST and AOO and late tonight further north and east.
Any light snow is likely to transition to spotty drizzle over
most of the region early Sat morning. However, SREF and
operational model soundings both indicate a likelihood of
lingering IFR CIGs over most of central Pa throughout Saturday
in the moist southeast flow ahead of the warm front. The warm
front is progged to work into southwest Pa during Saturday,
likely bringing improving conditions to JST, and possibly AOO.
Outlook...
Sun...AM low CIGs likely, mainly BFD/JST.
Mon...Early AM low CIGs possible BFD/JST. PM shra/low CIGs
possible BFD/JST.
Tue-Wed...No sig wx expected.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 AM EDT Saturday for
PAZ004>006-010>012-017>019-027-028-037-041-042-045-046-049>053-
056>059-063>066.
Winter Weather Advisory until 11 AM EDT Saturday for
PAZ024>026-033>036.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...Dangelo/Gartner
LONG TERM...Watson/Steinbugl
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Dodge City KS
611 PM CDT Fri Mar 17 2017
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Saturday)
Issued at 111 PM CDT Fri Mar 17 2017
High pressure over the greater region will eventually shift off to
the east through the overnight. SE/S winds are eventually expected
on the backside of the departing high. These winds will keep
minimums up a bit with upper 30s to lower 40s. There will be some
high level clouds, but no precipitation within the short term
domain. For tomorrow, pleasant temperatures are expected with
widespread 70s. Critical fire weather conditions are not expected
as relative humidities will be on the marginal side.
.LONG TERM...(Saturday night through Friday)
Issued at 111 PM CDT Fri Mar 17 2017
On Sunday, there will be stronger downslope conditions and 850-hPa temperatures
will warm well into the 20s. Critical fire weather conditions could
be possible across far western Kansas. One caveat to this is winds.
The strongest winds and lowest relative humidities do not appear to
be collocated at this time. This is something to watch. Regardless,
Sunday will be hot with highs around 90. It probably won`t take much
for a fire to start. It is too early for a fire weather watch given
the uncertainty with the wind magnitude.
For Monday, cooler conditions are expected behind a fropa with upslope
conditions. Even cooler temps are expected Tuesday/Wednesday as cold
air advection and upslope flow continues.
Attention then turns Thursday. The EC and GFS are quite different in
regards to the warm sector. The GFS has a larger area in the moist/warm
sector with convection possible. The EC downslopes/dryslots much of
the region. These details will be hammered out as time moves forward.
Something to watch as there could be very high fire danger west of
the dryline and/or thunderstorms (possibly strong/severe) east of the
dryline. Uncertainty is just too high right now to go into all the
smaller details.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 606 PM CDT Fri Mar 17 2017
Easterly winds less than 10 knots will become southeast between
09z and 15z Saturday, as surface boundary remains nearly
stationary across eastern Colorado and an area of high pressure at
the surface moves into the Mississippi Valley. As surface
pressures continue to fall along this bounary on Saturday the
southeasterly winds will increase into the 15 to 20 knot range
between 15z and 18z Saturday at Garden City and Dodge City. Gusty
southeast winds at around 15 knots will develop in the Hays area
between 18z and 21z Saturday. RAP and NAM model soundings
indicating VFR conditions over the next 24 hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 73 52 91 / 0 0 0 0
GCK 39 76 49 91 / 0 0 0 0
EHA 40 78 51 90 / 0 0 0 0
LBL 40 76 51 92 / 0 0 0 0
HYS 37 72 48 88 / 0 0 0 0
P28 42 73 52 91 / 0 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sugden
LONG TERM...Sugden
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
651 PM CDT Fri Mar 17 2017
.AVIATION... /00z TAF Package/
Made only minor adjustments to the 18z TAF package as general
forecast appears to be on track. All terminals are now VFR and winds
have started to drop down from being gusty during the day. MVFR
stratus will return by 06z at the I-35 terminals and around 09z at
DRT with cigs continuing to drop to IFR by 08z along I-35, and 12z at
DRT. Numerical MOS guidance and some high resolution models do show
a few hours of possible LIFR conditions right around sunrise, but
models have been a bit bullish with low cigs the last few days, so
have held off including those in the TAFs. As confidence is low in
the LIFR cigs at this point, have opted to go with low end IFR for
SAT/DRT where models were hinting at the LIFR cigs. With lighter
winds some patchy fog is possible at the terminals through the
morning hours, but only expected visibility to drop to around 3 SM.
Improvement will be slow during the day tomorrow with MVFR by 18z and
VFR by 21z at all terminals. Winds will not be a gusty on Saturday
as they were today, but still southeasterly at 10 to 13 knots.
&&
.PREV DISCUSSION... /ISSUED 256 PM CDT Fri Mar 17 2017/
SHORT TERM (Tonight through Saturday)...
Continued quiet conditions expected through the short-term as typical
cloudy mornings give way to partly sunny afternoons with near normal
to slightly above normal temperatures.
Slight northwest H5 flow is ongoing over the region per latest RAP
and water vapor analysis as a weak mid-level ridge develops over
northwest Mexico. Surface high pressure however is more centered
over the northern gulf coast and this is allowing for persistent
southeast and south winds that will keep ample low-level moisture in
place. Despite the moisture, weak to moderate convective inhibition
and H5 ridge suppression will keep showers at bay. There will be a
few showers and thunderstorms over the higher terrain of Mexico off
the Serrnias del Burros mountains. This activity is not expected to
make it into the lower terrain of the Rio Grande Plains today nor
tomorrow. Another cloudy start is expected Saturday morning with a
similar diurnal cloud mixout to today.
LONG TERM (Sunday through Friday)...
Mostly tranquil conditions will persist through at least Thursday
with no airmass changes expected with weak high pressure over the
region. Above normal temperatures are expected through the period
with a pattern change late next Thursday into Friday as a weak cold
front and showers/storms appear more likely.
Global models agree on an extended quiet period as H7-H3 ridging
remains mostly in place across Texas late weekend through middle of
next week. Expect cloudy mornings each day with gradual mixing
during the afternoons leading to partly sunny afternoons.
Temperatures will remain above normal with low to mid 60s each day
and highs reaching the upper 70s to low 80s most areas. Mid and upper
80s will be likely across the Rio Grande Plains. While some showers
and a few thunderstorms are expected over the higher terrain of
Mexico above the capping inversion, it is not likely to shift farther
east.
By late week, global models continue to advertise a much stronger
longwave trough axis to shift across the west coast and into the
south-central CONUS plains. The GFS has slowed towards the EC output
but still remains farther south of the two storm track solutions.
Have delayed shower/storm activity until Thursday night and Friday
morning this forecast package. This time frame is not as supportive
to capture the typical maximum diurnal instability max in support of
strong to severe storms but will continue to watch as lapse rates,
divergence aloft, and wind shear appear supportive of storm
generation. A weak cold frontal passage is likely sometime Friday
when rain/storm chances appear to be highest.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 83 64 83 63 81 / 10 10 - 10 -
Austin Bergstrom Intl Airport 83 63 82 62 82 / 10 10 - 10 -
New Braunfels Muni Airport 83 62 82 62 81 / 10 10 - 10 -
Burnet Muni Airport 80 61 79 60 80 / 0 10 - 10 -
Del Rio Intl Airport 88 64 83 64 84 / 0 0 - - -
Georgetown Muni Airport 81 63 81 61 81 / 10 10 - 10 -
Hondo Muni Airport 85 61 83 61 83 / 10 - - 10 -
San Marcos Muni Airport 82 63 82 62 81 / 10 10 - 10 -
La Grange - Fayette Regional 82 64 83 62 82 / 10 10 10 - -
San Antonio Intl Airport 83 63 83 63 82 / 10 10 - 10 -
Stinson Muni Airport 84 63 82 62 82 / 10 - - 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Treadway
Synoptic/Grids...24
Public Service/Data Collection...33
Area Forecast Discussion
National Weather Service Grand Forks ND
1037 PM CDT Fri Mar 17 2017
.UPDATE...
Issued at 1037 PM CDT Fri Mar 17 2017
Cloud mass is not moving eastward as quickly as short range models
depict or as forecast expected. So will adjust package to slow
cloud cover recision a bit. Min temp fcst may need slight
adjustment as well, mainly in northwest MN, to account for
shortened period of radiational cooling prior to sunrise.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 300 PM CDT Fri Mar 17 2017
The main forecast challenge will be diminishing winds and
snow showers. First of all, ended up issuing a wind advisory for
the northern Red River Valley until 7 PM. There have been pretty
strong winds around Winnipeg than have shifted southward into the
northern valley. The HRRR shows these winds holding through the
late afternoon and then decreasing through the early evening. The
light snow showers have now shifted just east of the Red River
Valley, extending from west of Roseau to near Detroit Lakes. These
will also linger into the late afternoon or early evening before
diminishing. Cloud cover will slowly decrease from west to east
tonight, so expect Saturday to be markedly different. There will
be light winds and some sunshine with highs a few degrees warmer
than today.
.LONG TERM...(Saturday night through Friday)
Issued at 300 PM CDT Fri Mar 17 2017
An upper ridge will be over the area on Saturday night, drifting
east as an upper level trough pushes onto the BC/WA coast. A plume
of warm air will exist ahead of the upper trough and a surface warm
front will push east across the area on Sunday. Highs on Sunday
should be in the 40s north to 50s south. Clouds will be on
the increase from the west on Sunday as well, with some rain
possible late in the day or during the evening hours as a cold front
pushes through the region. A cooling trend is expected for Monday
and Tuesday following Sunday`s warmth. However, Tuesday`s highs will
be rather close to normal in most areas.
Temperatures stay slightly above normal through the rest of the
week. Also, precipitation chances increase for Wed-Fri. As the cold
surface high drifts east and warm air pushes back toward the
region, rain or snow will be possible. The best chance may come on
Thursday night and Friday as a strong Colorado low moves out onto
the plains. However, the precipitation associated with this low may
stay to the south of the area as models differ on the details this
far out in time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Updated at 1037 PM CDT Fri Mar 17 2017
Widespread MVFR CIGS will steadily shift eastward and out of the
FA through 12z.
In eastern North Dakota... expect scattered MVFR CIGS to diminish
west of a Langdon-Cooperstown-Gwinner line by 01z. East of that
line... expect areas of MVFR CIGS to diminish from 02 to 04z.
Widespread MVFR CIGS will persist across the Red River Corridor
through 06z... with VFR conditions after.
Across northwest Minnesota... Expect widespread MVFR CIGS to
persist through 07z... then slowly erode from the west through
12z... with VFR conditions after.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Gust
SHORT TERM...Godon
LONG TERM...Knutsvig
AVIATION...Gust
Area Forecast Discussion
National Weather Service Green Bay WI
647 PM CDT Fri Mar 17 2017
Updated aviation portion for 00Z TAF issuance
.SYNOPSIS...
Issued at 239 PM CDT Fri Mar 17 2017
Fairly quiet mid-March weather until the end of next week.
The large scale pattern over eastern North America will reamplify
the next couple days, then flatten again. Next week it will
gradually evolve to more of a split flow regime. Temperatures
will vary with the passage of each weather system, with no extreme
warm or cold expected. Overall, readings will probably end up
averaging a little above normal for the next 7 days. Precipitation
totals for the period will depend primarily on what falls late
next week as a southern stream storm system in the evolving split
affects the area.
&&
.SHORT TERM...Tonight and Saturday
Issued at 239 PM CDT Fri Mar 17 2017
The main short-term forecast issue is aligning weather elements
with the passage of a frontal system through the region this
evening. A small area of clearing immediately behind the front may
brush the southwest corner of the area early, allowing a brief
period of warm temperatures in that area. Otherwise, low clouds,
some fog, and drizzle will persist in advance of the front. Clouds
are widespread behind the front as well (except as mentioned
above), though a shift to west winds was resulting diminishing
fog over western Wisconsin. The fog may be a bit tougher to
dislodge from eastern Wisconsin since an inch or two of snow is
now on the ground and dewpoints have edged above freezing. Will
keep some fog into the evening, especially over the far east. But
do not expect visibilities to continue to drop once winds shift
west. Some mid-level moisture will shift back southeast into the
area this evening. Forecast soundings off the NAM, RAP and HRRR
suggest this will eventually result in a moist layer deep enough
to result in ice crystals. So gradually transitioned
precipitation from drizzle to snow showers and flurries overnight.
Quiet weather and a slow decrease in clouds is expected Saturday.
Trajectories will be favorable for lake-effect off Lake Superior
to work into north-central Wisconsin. But large-scale subsidence
and drying suggest just scattered snow showers and flurries are
likely, with only minor accumulations possible.
.LONG TERM...Saturday Night Through Friday
Issued at 239 PM CDT Fri Mar 17 2017
Main forecast concerns in the long term are timing/strength and
precip types with a weak system Sunday night into Monday then with
a much larger/stronger system toward the end of the week.
Dry weather is expected Saturday night as surface high pressure
and upper level ridging spread across the western Great Lakes. The
surface high quickly slides east of the area Sunday with the upper
flow becoming more zonal as an upper jet rides along the southern
part of a trough over Canada. Within the zonal flow, a cold front
will sag across the area Sunday night into Monday, along with
decent warm air advection (WAA) as 850mb temps climb 5-7C from
Sunday AM to Monday AM. The best forcing and moisture stays well
north of the area, but with the approaching cold front, WAA, and
some moisture being advected in on south winds. Think slight
chance / chance POPs are reasonable as there should be some
isolated/scattered shower activity, especially overnight Sunday
into Monday morning as model soundings continue to show some
saturation below 750mb. Temp profiles look warm enough for rain
for most of the period, but some snow could mix in over northern
WI, mainly with any post-frontal precip Monday morning.
Dry weather returns to the area behind the front as a sprawling
area of surface high pressure moves from northern Saskatchewan
Monday night to WI on Wednesday. The only exception could be far
north-central WI where some light lake effect activity is possible
from Monday night through Tuesday night as the colder air flows
over the relatively open waters of Lake Superior. However, the
high will bring some pretty dry air with it, so not expecting
much accumulation, if any, over northern WI.
As the high pressure shifts east of the Great Lakes later in the
week, attention turns to a developing low pressure system in the
Plains on Friday. A split flow aloft will make for a complicated
forecast as phasing/timing is always difficult. First, we will
have to deal with WAA and a warm front which will kick off an area
of precip Wednesday night. GFS is the most aggressive and
farthest east with the precip associated with these, with the
ECMWF and Canadian not as bullish as they hang on to some drier
air on the western side of the departing high pressure. Will put
some low POPs across north-central Wisconsin to cover for now, but
if there is more moisture available, those features could bring a
shot of wintry weather to the area before the main system
arrives. Although long range models are not drastically different
with the main system at the end of the week, there are still many
details to worked out. It is safe to say precip is looking likely
Thursday night into Friday, but who gets rain, snow, storms?, and
how much of each will have to play out the next few model runs.
Temperatures will be above normal Sunday into Monday, then a
return to near or slightly below normal behind the front on
Tuesday/Wednesday. Temps look to climb back to above normal ahead
of the next system next Friday.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 647 PM CDT Fri Mar 17 2017
Ceilings across parts of the forecast area improved during the
late afternoon as winds shifted to light southwest. Part of
central and east central Wisconsin had MVFR and even some VFR
ceilings, but IFR visibility was the general rule due to mist
and/or drizzle.
Have a trend toward VFR visibility during the evening remaining
that way overnight through Saturday. Models showed deeper moisture
later tonight so think that MVFR ceilings with areas of IFR will
be the rule overnight, then conditions should improve to VFR on
Saturday. Have included a mention of flurries overnight as a cold
front and upper trough move into the state. Scattered MVFR/IFR
ceilings and MVFR visibility possible in lake effect snow showers
across far northern Wisconsin.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....Skowronski
LONG TERM......Bersch
AVIATION.......MG
Area Forecast Discussion
National Weather Service Huntsville AL
812 PM CDT Fri Mar 17 2017
.NEAR TERM...(Tonight)
Issued at 810 PM CDT Fri Mar 17 2017
The storms over NE AR/W TN formed at the edge of a deeper moisture
plume where dewpoints in the 60s were nudging into the area. For
a brief window they appeared to be surface based but as the storms
continued to shift E/SE they move out of the better moisture and
have taken on a more elevated look. The TN Valley remains on the far
eastern edge of the better moisture and with the better upper level
lift/support staying well to our NE we can expect the storms to remain
elevated as they enter the area after midnight.
NCAR Ensembles and the last few runs of the HRRR all suggest
limited MUCAPE, with values generally less than 250 J/kg. Deep layer
shear is also limited with only about 20 to 30 kts. So, with those
values in mind and based off the latest radar trends, think storms
remain below strong/severe limits. A gust or two of 30 mph is possible
but will be isolated. We can expect moderate to heavy rain with the
storms and rainfall totals between 0.25 and 0.40 are possible.
Made some tweaks to the grids based on the latest trends. But the
forecast timing of the storms through the area is looking good.
Will keep an eye on the line and might make another adjustment
later if the storms speed up any. The rest of the forecast is in
good shape and no other changes are needed at this time.
.SHORT TERM...(Saturday through Sunday Night)
Issued at 248 PM CDT Fri Mar 17 2017
Areas along and southeast from Fort Payne to Cullman will still have
stratiform precipitation falling at the rear of the MCS through
12-14Z. Then a rapid clearing trend should take place behind the cold
front. Temperatures do not drop off too significantly behind this
front with advection becoming about neutral during the afternoon.
Highs should still recover into the mid to upper 60s in valley
locations (lower 60s atop the higher elevations). As the surface
ridge axis shifts east across the lower OH and TN valleys on
Saturday Night, patchy frost will be possible in southern TN and much
of north central and northeast AL. On Sunday, the 850 mb ridge axis
shifts into TN and AL. Limited mixing of the low level inversion
layer near 900 mb is indicated by the forecast soundings which may
keep afternoon highs in the lower to middle 60s.
.LONG TERM...(Monday through Thursday)
Issued at 248 PM CDT Fri Mar 17 2017
Southwesterly low level winds (below 850 mb) will continue to
increase over the area ahead of a developing frontal boundary over
Missouri and Oklahoma on Monday. With very warm temperatures
advecting in low levels and adequate mixing, a very warm day is
expected with highs in the upper 70s to around 80. Winds will also
increase to around 10 mph with gusts to around 20 mph. Primarily
partly cloudy conditions are expected, with weak isentropic lift in
the area.
The frontal boundary is forecast to slide southeast overnight.
However, it still should remain north of our Tennessee counties
through daybreak. However, isolated to scattered showers and
thunderstorms look reasonable as the atmosphere becomes more moist
and convergence increases on Tuesday (especially near and north of
the Tennessee River). Although shear is not that impressive, there
may be just enough deep layer shear(~ 35 kts) to allow for some
storms to become strong. Surface based instability increases to
around 1200 J/KG in the afternoon. This along with a bit of drier air
aloft, may produce wind gusts between 40 and 50 mph in stronger
storms through ~ 7 PM on Tuesday. Overall though lift is not
especially strong with this system, so coverage is not expected to be
too widespread (30-50 percent coverage). Between 1/10 and 1/4 of an
inch of rain looks reasonable in most locations, with some isolated
higher amounts in stronger thunderstorms. Models keep this frontal
boundary between north and central Alabama through Wednesday, but
weaken it significantly. As cloud cover and scattered showers remain
over the area as a result, the atmosphere should remain worked over
and pretty stable overall. So kept only showers in the forecast
Tuesday night through Wednesday. Cold air advection should lower
highs back into the 60s primarily.
This boundary slowly falls apart before a stronger system develops
over the southwestern U.S. and moves east toward the Tennessee Valley
Thursday night into Friday. This should warm temperatures back into
the 60s at least (maybe a bit higher given the strong ridge
forecast). Both models show a very strong ridge ahead of this
system. Therefore, the GFS quicker movement east of this system
seems a bit too fast. Thus timed precipitation slower and adjusted
temperatures closer to the ECMWF. This could produce isolated
showers and storms on Friday, but a better chance of activity likely
will be Friday night or early next weekend. This system in most
models have very strong forcing associated with it. This combined
with good shear/helicity and strong southerly flow/moisture
advection ahead of it could produce some strong to severe storms
sometime next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 628 PM CDT Fri Mar 17 2017
A cold front will move across the area between 04-08Z this evening.
Showers and thunderstorms will accompany the front and the current
timing in the TAFs is consistent with latest model forecasts. Expect
CIGs to remain VFR until the storms arrive, then drop to MVFR with
brief periods of IFR under the heavier showers. Winds with the storms
could gust upwards of 40 mph.
Clouds begin to clear to VFR Saturday morning as drier air spreads
into the area. Gusty northwesterly winds are expected after 16Z
Saturday and will continue through the early evening hours.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...Stumpf
SHORT TERM...17
LONG TERM...KTW
AVIATION...Stumpf
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Wilmington OH
1152 PM EDT Fri Mar 17 2017
.SYNOPSIS...
Surface Low pressure will track through the Great Lakes, with an
associated cold front moving through the area late tonight.
Patchy drizzle and fog will continue into the early morning
hours Saturday. Saturday afternoon some rain or snow showers
will be possible, as an upper level low settles into the Great
Lakes. High pressure will move over the area again Saturday
night and Sunday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Collaborated with IND/IWX to work out a dense fog advisory for
part of the forecast area. Fog is expected to continue to
thicken over the next several hours ahead of the cold front, not
really improving until morning. Would not be surprised if this
advisory needs to be adjusted (perhaps expanded east or slightly
later in time) later on the midnight shift. No other changes as
of now.
Previous discussion >
Temperatures are currently near freezing across our
northeastern zones with mid 40s across northern Kentucky. This
is thanks to a surface warm front that pushed north into the
southern zones of the forecast area before coming to a halt. A
surface cold front is also pushing east with a clearing line now
in IN. Ahead of this front fog and patchy drizzle prevail.
Overall thinking is for the clearing line to slowly push
southeast through the night with the latest RAP now showing the
clearing conditions possibly clipping the southwestern half of
the forecast area. Looking at the latest HRRR and RAP forecast
soundings though would tend to favor fog hanging around until 8
or 10 am Saturday morning. For now have kept forecast package
reflecting this. Have also issued an SPS mentioning the reduced
visibilities across the forecast area.
Saturday afternoon lapse rates will be moderately steep with
forecast soundings across the northeastern zones indicating the
DGZ saturating. This also means that some of the scattered rain
showers might mix with snow Saturday towards CMH. New zones
already out.
Prev Discussion ->
Surface low pressure to track east across the southern Great Lakes
overnight into Saturday. Widespread precipitation associated with
isentropic lift and low level jet has pushed east of ILN/s area.
Temperatures have been slow to warm ahead of northward
advancing warm front. There may be a few locations that are
still around 32 degrees but with continued warming will allow
the advisory to expire and will issue SPS for any lingering
slick spots.
Weak elevated instability was leading to a few thunderstorms and
additional shower development over southeast Indiana/southwest Ohio
along and ahead of the warm front. Some of these storms may
contain small hail. Have added a mention of thunder early in
the forecast across the south to account for this threat.
Pops will diminish overnight with the cold front pushing east thru
ILN/s FA between 05Z and 09Z. Expect to see low clouds overnight
with lows generally in the mid and upper 30s.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Mid/upper level low to dig southeast into the Great Lakes Saturday.
CAA across the area will steepen low level lapse rates which
will result in widespread clouds. With PV anomaly pivoting thru
expect to see the development of showers. The cold temperatures
aloft will be observed across our northeast counties. Therefore,
have highest pops over the northeast with a rain/snow mix
expected to change to snow toward evening. Expect highs to range
from near 40 north to the mid 40s south.
As the upper level low tracks off to the mid Atlantic a northwest
flow will develop. Surface high pressure will build into Saturday
night into Sunday. Expect pcpn to end Saturday evening with
diminishing clouds overnight. Lows to range from the upper 20s
northwest to the lower 30s southeast.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
High pressure and a dry airmass will build east across the region
through the day on Sunday. Temperatures will be fairly seasonable
with highs ranging from the mid 40s in the northeast to the lower
50s across the southwest.
An upper level trough will pivot across the Great lakes Monday into
Tuesday helping to push an associated cold front down across the
Ohio Valley Monday into Monday night. In developing southwesterly
low level flow out ahead of this, showers will develop through
Monday morning and become more numerous Monday afternoon into Monday
evening. Instability is somewhat limited but it looks like there may
be enough to support at least a chance of some embedded
thunderstorms Monday afternoon and into the evening. With some WAA
out ahead of the front, highs on Monday will range from the mid 50s
in the north to the low to mid 60s across the south.
High pressure and a drier and cooler airmass will build in behind
the front for Tuesday and Wednesday. Highs on Tuesday will be in the
upper 40s to mid 50s, cooling into the low to mid 40s by Wednesday.
A chance of showers will return through late in the work week as a
warm front lifts north across the region. In developing WAA, highs
by Friday will be into the 60s across much of the area.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
A warm front has lifted north and stalled around KCVG and KLUK
this evening with a surface low located across southern Canada.
A cold front was also extending south through IL and IN. A
clearing line can be seen on low light in association with the
surface cold front. Currently TAF sites are mostly LIFR or IFR.
High res guidance for the most part has the clearing line diving
southeast this evening with only possibly CVG/ LUK seeing some
brief clearing. The RAP and GFS low level RH do show some
possible clearing as far north as KILN (between 5 and 10z)
though. The clearing appears that it will transient though.
The cold front will likely pass through the TAF sites around
3z. Low level CAA will help to only reinforce the low ceilings
especially across the north and east behind the clearing line.
Saturday afternoon ceilings will slowly start to rise towards
MVFR with some wind gusts of 20 to 25 kts possible. As lapse
rates steepen there will be a chance of some scattered rain
showers. Thermal profiles do support some snow mixing in across
the north but have left the mention out for now.
OUTLOOK...MVFR ceilings and visibilities possible into Monday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Dense Fog Advisory until 8 AM EDT Saturday for OHZ026-034-035-
042>044-051>053-060>062-070>072-077.
KY...None.
IN...Dense Fog Advisory until 8 AM EDT Saturday for INZ050-058-059-
066-073-074.
&&
$$
SYNOPSIS...Haines/AR
NEAR TERM...Haines/Hatzos/AR
SHORT TERM...AR
LONG TERM...JGL
AVIATION...Haines
Area Forecast Discussion
National Weather Service Lincoln IL
905 PM CDT Fri Mar 17 2017
.UPDATE...
Issued at 855 PM CDT Fri Mar 17 2017
Northwesterly winds and mostly clear skies north of the mid and
high level clouds that are settling over the southern half of the
state. However, the clearing will be short lived as low clouds
under a deep upper level low begin to settle into the region.
After midnight, expect the low clouds to creep south into Central
Illinois. HRRR/NAM/RAP have differing solutions as to how far
south the clouds will settle...which will do little to impact
overnight lows as northwesterly winds will continue to push cooler
air into the region. No major updates are anticipated at this
time.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 254 PM CDT Fri Mar 17 2017
Cold front has entered the northwest part of the forecast area early
this afternoon, and was roughly along the Illinois River at 2 pm.
Some nice clearing has taken place west of it, and temperatures have
quickly risen into the lower 60s from Galesburg to Jacksonville and
was even near 70 toward Quincy. Eastern CWA remains socked in and
temperatures were only in the mid 40s.
Much of the forecast area is expected to be clear by sunset.
However, stratocumulus clouds over the upper Mississippi Valley have
started to sink across the Iowa/Minnesota border. 925 mb humidity
plots off the RAP model suggest this reaching the northern part of
the CWA mid to late evening, and encompassing a good part of it by
morning, as an upper low tracks southeast across the western Great
Lakes region. Not going quite that fast yet in the gridded forecast,
but will bring mostly cloudy skies to the I-74 corridor toward
midnight and over the rest of the forecast area early Saturday
morning. This should diminish from west to east as the upper low
pulls away. Temperatures tomorrow should be fairly similar to
today`s cloudy areas, but some 50s will be possible if the clouds
move out fast enough.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 254 PM CDT Fri Mar 17 2017
The last half of the weekend will start out with high pressure
shifting east of Illinois, and a southerly flow developing. 850mb
temperatures will climb steadily from 00z/7pm Saturday through
Sunday night. That will result in high temps on Sunday climbing into
the mid to upper 50s, with lows Sunday night remaining in the mid to
upper 40s. The low temps will be held on the mild side by a blanket
of clouds and increasing chances of rain and storms after midnight.
The SPC Day 3 outlook indicates a Marginal Risk for our counties
west of I-55 for Sunday night through 12z/7am Monday. This appears
reasonable due to GFS MUCAPE values in the 600-1000J/kg range on
the nose of a developing low-level jet streak late Sunday night.
The storm chances will be shifted slightly southward on Monday as a
cold frontal boundary drops southeast across Illinois. The slower
forward speed of the frontal passage may lower the potential of a
continued severe threat into Monday, but rain chances will continue
through the day southeast of the Illinois River, in the vicinity of
the stalling front.
Rain chances should generally come to an end on Tuesday as the front
progresses toward the Ohio River Valley. We will carry just some
slight chances of rain in our far southern tier of counties, due to
the close proximity of the front just to our south.
High pressure moving from south central Canada into the Great Lakes
will provide dry and seasonable temperatures for Tuesday night
through Wednesday night. Rain chances increase again on Thursday,
as a warm front lifts through Illinois. On Friday, a cold front
will approach Illinois, helping to trigger another round of rain
and a few thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 701 PM CDT Fri Mar 17 2017
Low pressure sliding across the Great Lakes this evening pushing
clouds into the nrn ILX terminals...PIA and BMI most likely to see
cloud cover as a result. Timing of the clouds vary from
08-12z...and the HRRR is far lower into the MVFR cat than the
RAP13 at closer to 8000ft. Have pushed the forecast closer to the
HRRR for PIA and BMI due to current cigs north of IL.
Northwesterly winds throughout...staying up overnight to limit fog
development. Expect scattering out tomorrow afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Geelhart
LONG TERM...Shimon
AVIATION...HJS
Area Forecast Discussion
National Weather Service Lubbock TX
625 PM CDT Fri Mar 17 2017
.AVIATION...
Low CIGS and visbys will likely return early Saturday morning.
Although a cold front has brought easterly winds, strong moisture
will move into the area from the east. Best chances exist at KLBB
and KPVW for low visbys and CIGS. KCDS may only see low CIGS with
little to no visby restrictions. Lowered flight conditions will
likely take up much of the morning hours with low CIGS not
expected to clear until early Saturday afternoon.
&&
.PREV DISCUSSION... /issued 325 PM CDT Fri Mar 17 2017/
SHORT TERM...
Surface observations at 2 PM placed a weak cold front from near
Seminole northeast to Guthrie. Northeast winds behind the front were
already tapping richer moisture upstream in Oklahoma, and this theme
will persist overnight into early Saturday as the front slows just
to our south. This process will keep a steady fetch of rising
dewpoints directed across the CWA, likely culminating in advection
stratus and some fog by early Saturday with lesser chances for
drizzle given generally shallow saturation of the non-NAM guidance.
Current expectation is stratus to develop after midnight near the
Red River and expand W-SW onto the Caprock before daybreak. NAM
looks to be a fast outlier with the rate of stratus development, so
have sided more toward the slower HRRR, RAP and GFS.
As surface ridging nudges south from the Panhandles on Saturday,
cool and moist upslope winds will persist for much of the day and
delay the erosion of stratus. Such a pattern warrants keeping highs
on the cool end of the MOS spectrum, especially on the Caprock where
moist upslope winds will persist through peak heating.
LONG TERM...
The moisture feast early in the weekend will continue Saturday
night and early Sunday. Possible we will see more stratus early
Sunday morning. An upper ridge will remain overhead with weak flow
aloft, and a very modest surface dry-line will evolve within a
surface trough across the area. To our southwest late Sunday,
solutions were indicating thermally driven updrafts capable of
breaking through into high-based showers or thunderstorms off the
higher terrain in south-central New Mexico that may also attempt
to fill in along the dryline near the Texas-New Mexico border
early Sunday evening. We think flow will be incapable of serious
chances for these running across the border, but still worth
paying some attention to in the next several solution runs. The
high-based showers with lightning and moderate south to southwest
breezes would be a concern for land managers given the remaining
cured grasses in this area. Oh - and solutions have maintained
near record highs on Sunday with H850 temperatures over 25 degrees
Centigrade on the Caprock.
Monday somewhat similar, a surface trough with ridge aloft, but
somewhat depleted low level moisture. Temperatures may crank up a
notch over Sunday with slightly warmer air spreading overhead. A
cold front we have been eyeing appears incapable of moving out of
the Panhandle on Monday at least.
Front will surge southward late Monday night and early Tuesday,
knocking temperatures back 10-15 degrees for most of the area,
perhaps to within 10 degrees or less of normal. Solutions mixed
about convective generation along the front Tuesday and we have
kept a dry forecast at this time.
East-southeast flow appears capable of returning moisture into
the area by Wednesday and early Thursday. Especially as flow
aloft backs in advance of an energetic eastern Pacific trough
crossing the southwest coast Wednesday night before crossing the
central Rockies Thursday, emerging into the central high plains
Thursday night. Solutions remain in decent enough continuity this
far out - note however that the ECMWF was a no-show for todays
consideration. Low level warm advection Wednesday night and early
Thursday appears capable of a low mention of thunder before deep
layer drying prevails Thursday. Thursday still looks likely to
become a strong wind day with dust and fire weather concerns as
previously indicated.
Drier, slightly cooler, less wind, and more settled weather
should follow next Friday as long as flow aloft remains
progressive. RMcQueen
FIRE WEATHER...
Next Thursday appears a likely critical fire weather day as the
next potent wind system generates over the southern high plains.
Elevated fire danger may flirt with the high plains Sunday and
Monday afternoon, though wind speeds appears mediocre. Keep in
mind, however, the potential for a few high-based thunderstorms
nearing the southwestern South Plains late Sunday afternoon or
evening. RMcQueen
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
01
Area Forecast Discussion...Updated
National Weather Service Little Rock AR
700 PM CDT Fri Mar 17 2017
.UPDATE...
Some thunder is noted in northeast Arkansas this evening. Also
a few showers trying to develop in southwest Missouri and
build into northwest Arkansas.
Latest HRRR data continues to show scattered showers/isolated
thunderstorms developing north of Little Rock this evening.
After midnight, data has been trending toward a decline in
precipitation across the north, with development across the
southern counties.
Have gone with the latest trends, and adjusted POPs/QPF to show
a shift in precipitation from north to south overnight. (46)
&&
.AVIATION...
Widespread low clouds/MVFR conditions will be noted late tonight
and Saturday morning, especially over central and southern
Arkansas.
Scattered showers/isolated thunderstorms will develop overnight.
Precipitation will be mainly over northern sections of the state
this evening, and over the south after midnight.
Precipitation will be ahead of a cold front pushing through the
region from the north. Ahead of the front, southwest winds will
prevail at 5 to 10 mph. Winds will shift to the north/northeast
behind the front.
Conditions will become VFR/clouds will clear out from north to
south behind the front as the day progresses on Saturday. (46)
&&
.SHORT TERM...Today Through Sunday
Quick Synopsis... Water Vapor imagery shows upper level trough
across the Northern Plains and Upper Mississippi Valley regions
amplifying and moving southeastward towards the Ohio Valley. A
cold front extends down from the associated surface low through
the Upper Miss Valley and through the central plains. The cold
front is expected to push across Arkansas in the evening and
overnight hours before stalling out near the Louisiana border
from a lack of upper support.
This evening and tonight... Models have done a terrible job in the
short term. Cloud cover has not been quite as thick as initially
progged, resulting in a little more insolation and thus warmer
temperatures. Resultant stronger boundary layer mixing combined
with strong mid-level winds have made for a fairly gusty day by
Arkansas standards. Have adjusted temperatures and winds
accordingly in the short term to account for these trends.
A few isolated showers attempted to get going across the
northeastern portion of the state, but dissipated soon after
initiation. The front should reach the northeast corner of the CWA
around 9pm CDT and reach southern Arkansas by sunrise. Scattered
showers will develop along the boundary, with an isolated
thunderstorm possible. Convective allowing models have trended
significantly downward with convection. Hail will be the primary
threat will any stronger storms that do mature well this evening
as a near-surface stable exists. MU CAPE will be between 1000 and
2000 J/kg, which is supportive for some stronger storms. However,
the deep layer wind profile (marginal deep layer shear and
backing winds in the mid-levels) and lack of upper level support
should prohibit robust development of thunderstorms.
Have decreased POPs just a bit from the previous forecast and
opted to go slightly below WPC guidance in the near term based on
aforementioned radar and CAM trends. The front is expected to
stall out across southern Arkansas tomorrow morning.
Saturday and Sunday...
Unlike the near term, models are in very good agreement for the
remainder of the weekend. The aforementioned frontal boundary
will become more diffuse through the day on Saturday as high
pressure builds into the region and then slides eastward. At this
point, deep and well- defined ridging across the US interior and
associated subsidence will prohibit much else in the way of
convection from initiating. By Sunday, southerly winds return to
the area, advecting in warm moist air into the region.
Temperatures will be a bit above average on both Sat and Sun.
.Long Term...Sunday Night through Friday
By Sunday night, the area will be in the warm sector of the next
approaching surface system. Increased gradient will allow for gusty
southwest winds on Monday, ahead of a cold front. As a result,
temperatures should have zero problems climbing well into the 80s in
much of the state. Cold front will move into the area Monday night
or early Tuesday, with scattered showers/storms developing as
several upper level systems interact with the front.
Frontal boundary will stall out near southern Arkansas, then back to
the north as a warm front around Thursday. Winds will be gusty again
as the gradient increases out ahead of the next front. This front
will affect the area some time late Thursday or on Friday, depending
on which model solution plays out. It`s one of those situations
where they agree on the overall large scale details but not the
timing.
At any rate, this next front will pack a bit more of a punch.
Showers and storms will accompany the system. With the pattern
setup, and given the large amount of shear expected over the area,
there could be a few severe thunderstorms. This will all depend on
the time of day the front moves through, and if there is enough
instability out ahead of the front. These details should become more
clear in the next few days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 50 71 44 67 / 50 0 0 10
Camden AR 60 74 54 78 / 40 30 0 10
Harrison AR 45 69 46 73 / 50 0 10 10
Hot Springs AR 57 73 53 75 / 50 30 10 10
Little Rock AR 56 72 49 73 / 60 20 0 10
Monticello AR 59 73 51 75 / 30 30 0 10
Mount Ida AR 56 72 53 76 / 50 30 10 10
Mountain Home AR 46 70 44 70 / 50 0 0 10
Newport AR 50 70 43 66 / 60 0 0 10
Pine Bluff AR 58 72 50 73 / 40 30 0 10
Russellville AR 54 73 51 75 / 60 10 10 10
Searcy AR 52 71 45 69 / 70 10 0 10
Stuttgart AR 56 71 48 70 / 60 20 0 10
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Short Term...Brown / Long Term...57
Area Forecast Discussion
National Weather Service Nashville TN
820 PM CDT Fri Mar 17 2017
.UPDATE...
FOR MESOSCALE DISCUSSION...
&&
.MESOSCALE DISCUSSION...
Current sfc front progressing very slowly ewd out of se MO and on
track to enter the Land Between the Lakes Region shortly before
06Z, pushing sewd out of the mid state region by 12Z. Latest SPC
mesoscale discussion saying that a convective watch being issued
for our area is highly unlikely, with most activity expected to
remain largely elevated. Taking a look at the KOHX 00Z SAT
sounding, it still shows rather steep mid level lapse rates so
hail potential is still probable, although only a few strong
thunderstorms are expected to develop remainder of the evening
with marginal svr hail the main concern. Sounding showing precip
water values around 1.17 inch with some marginal above mentioned
instability noted. Veering winds from the sfc-850mb with a 50kt
low level jet centered around 850mb is also noted. With no
concentrated lifting mechanisms as of note other than weak
shortwave passages in quasi nwly flow aloft associated ahead of a
more pronounced mid level short wave trough digging southeastward
across the upper Mississippi Valley/ upper Great Lakes region
this evening, expect potential of strong tstms to continue to
diminish thru the evening hrs. A couple of special wx statements
have already been issued previously this evening for the potential
of half inch hail. Overall not a lot of lightning strikes noted
across the mid state region presently also, with greatest
concentration of convective activity supporting numerous lightning
strikes noted across west TN.
Thus, will update the suite of forecast products to mention only
iso tstm potential for the remainder of the evening hrs. Current
HRRR model solution initializing well and pushing most of the
shwrs/tstms S of mid state after 09Z. Breaking news concerning
the Latest Day 1 convective outlook that recently came in that
has pushed the marginal risk potential further westward and out
of the western half of the Nashville Metro Area, with the
potential of any risk for hail generally expected over the next
two hours to remain marginal/isolated at best. With all this said
however, as this frontal system approaches and 850mb flow expected
to veer early tonight ahead of the front, there is the
possibility of training convective elements across southern
portions of the mid state tonight. WPC has placed areas generally
along and east of I-24 and locations generally south of I-40 in a
marginal 2-5 percent risk of excessive rainfall potential as
convection continues to move into that portion of the mid state
resulting in total rainfall amounts approaching in some iso
locations lower flash flood guidance values. Current temp trends
showing forecasted overnight low values being reached at CKV, but
latest GFS lamp showing the potential for much warmer lows at
BNA/CSV. However, this is based on clouds staying in longer than
previously anticipated. Will at this time hold off on raising any
low temps tonight, monitor temp and cloud trends, and take a
further look closer to the midnight hr.
Thus, with everything said above, will be updating the suite of
forecast products shortly to reflect these changes.
&&
.PREV DISCUSSION.../ISSUED /
Made some minor tweaks to the suite of forecast products for this
evening per expected model consensus of short ranging timing of
numerous shwrs and mainly sct tstms ahead of the associated sfc
cold front that is expected to move close to the Land Between The
Lakes Region by around 18/06Z and then push sewd thru the
majority of the mid state by 18/12Z. Tweaked hrly temp, dewpoint,
wind speed/direction grids also.
&&
.AVIATION...
00Z TAF DISCUSSION.
Showers and thunderstorms will push their way south through Middle
TN this evening. Some could become strong with small hail and
gusty winds. All terminals will see precip tonight. Currently the
front is situated across southeastern Missouri. As it approaches
the TN Valley precip coverage will likely increase. Expect cigs to
remain low through at least 08z at BNA and CKV and through 14z
CSV. Visibilities will also be reduced to 2SM or less especially
during times of heavier precip. After the frontal passage Saturday
morning, conditions will quickly improve to VFR. Winds will be
out of the northwest and may be gusty during the afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 50 64 34 59 44 / 100 10 0 0 10
Clarksville 45 61 32 59 44 / 100 0 0 0 10
Crossville 48 59 31 53 37 / 100 20 0 0 0
Columbia 52 65 34 60 43 / 100 10 0 0 10
Lawrenceburg 52 66 32 60 43 / 100 20 0 0 10
Waverly 48 63 35 60 46 / 100 0 0 0 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......31
AVIATION........08
Area Forecast Discussion
National Weather Service Blacksburg VA
1000 PM EDT Fri Mar 17 2017
.SYNOPSIS...
High pressure over the region will shift offshore this evening
ahead of a warm front approaching from the south. This front
will lift northeast through the area overnight before a trailing
cold front pushes across from the west during Saturday. High
pressure will follow the front on Monday, then another cold
front crosses the Mid Atlantic region Monday night.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 940 PM EDT Friday...
Undergoing a transition of wintery wx in the Alleghanys to
thunderstorms over the New River Valley, though should see
limited cloud to ground strikes as instability east of the
Appalachians wanes. Also very dry air aloft in places with
colder thermal structure allow for graupel/sleet to occur. This
noted across the Lynchburg area as of 930pm. Radar showing
bright banding/melting level around 4000-4500 AGL over Bedford
County.
Latest RAP13 showing area of moderate to heavier showers moving
out of the piedmont between 03-04z, with mix of sleet/snow
still possible until 1-2am EDT northeast of Lewisburg, WV to the
Alleghanys of Bath County. Handling with SPS for now, as only
getting minor accumulations. Temperatures running around
freezing at LWB/HSP.
Warm front situated from LEX-MWK this evening should head north
of us into the mid-Atlantic overnight allowing temps to
gradually warm above freezing.
Models still favoring overnight higher pops across the mountains
and south into the NC foothills and piedmont, as better jet
energy shifts southward toward 12z Saturday.
Previous discussion from mid afternoon...
Initial swath of precip along the leading edge of the deeper
warm advection aloft per latest model 850 mb temp gradient has
pushed across the northwest sections where saw a period of snow
where precip did reach the ground. Latest radar trends and HRRR
suggest a break in coverage to take shape once this initial
batch passes before deeper moisture ahead of the actual
warm/cold front combo arrives by early this evening. This may
bring another round of mix to far northwest sections before
temps aloft surge above freezing later this evening. However
some concern with dry air in that surface temps may still be
close to freezing around LWB/HSP. Thus keeping in a mix with
perhaps an inch or so of snow along the I-64 corridor but
without much freezing rain mention or advisory headline at this
point.
Otherwise models suggest a decent slug of lift crossing the region
espcly this evening before deeper moisture axis slides to the south
late as the front folds southbound. Appears deep westerly flow could
limit eastward expanse of rainfall but given a favorable jet aloft and
lots of forecast diffluence expect momentum to carry rain farther east
than usual. Therefore beefed up pops to push likelys out just east of
the Blue Ridge tonight and high chances south/east. Even included some
elevated thunder mention across the southwest per steep lapses and
dynamics with QPF of up to one quarter inch east to three quarters
west. Dropped lows below mos most spots given a chilly start and more
evaporative cooling potential with lows close to freezing northwest and
upper 30s/low 40s elsewhere before perhaps rising some late.
Cold front crosses the region Saturday followed by increasing northwest
flow and gradual drying by mid to late afternoon outside of the upslope
northwest zones. However models suggest that a weak wave may form along
the boundary over southern sections in advance of the strong dynamic
shortwave trough that will arrive late. This may slow the exodus of the
showers espcly southeast sections so left in decent chance pops south
early on before switching to mostly upslope rain showers west during
the afternoon. Expect to see enough clearing and warming before
stronger cold advection arrives to help boost highs to around 50 far
west to 55-60 Blue Ridge to mid 60s east. Will also turn windy as the
850 mb jet increases to 40+ knots under the onset of the stronger cold
advection but below advisory levels per forecast high inversion levels
and only weak subsidence.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 400 PM EDT Friday...
Upslope snow showers should pick up Saturday night along and west of
the Blue Ridge as an upper level trough pivots overhead. It appears
that up to a couple inches of snow seems likely for western
Greenbrier County tapering down to flurries in the New River Valley.
Good cold air advection warrants pushing lows on Sunday morning
below MOS guidance. Temperatures may struggle to increase initially
during Sunday due to cloud cover in the mountains, but high pressure
building from the north should allow skies to gradually clear by the
afternoon. By Sunday night, this high will move over the Appalachian
Mountains to allow another cold night with efficient radiational
cooling.
The upper level pattern becomes more zonal by Monday, and
some ridging arrives from the southern Plains. Expect a good warm up
on Monday, but clouds will steadily increase during the afternoon
and evening from the northwest as a cold front approaches the Ohio
River Valley. The 12Z GFS pushes this cold front into the CWA a
little faster than the 00Z ECMWF during Monday night. There may be a
lag in moisture arriving at the onset due to recovery from a cold
and dry air mass from Sunday and Monday, so the slower ECMWF
solution was favored. However, some rain showers will probably reach
southeast West Virginia after midnight.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 400 PM EDT Friday...
The cold front should move from northwest to southeast over the CWA
on Tuesday. Meanwhile, another upper level trough will dig southward
from eastern Canada to bring colder air behind the frontal passage.
If the cold air arrives quickly enough, it could change the rain to
snow in the higher elevations of southeast West Virginia and the
northwest North Carolina mountains by Tuesday night. Cold air
advection will continue through Wednesday as a strong high pressure
area builds southeastward from the Great Lakes. Once overhead by
Wednesday night, expect another cold night with temperatures well
below freezing. This high should slide eastward toward the coast on
Thursday, and the numerical models hint that some wedging may occur
east of the Blue Ridge. A warm front will also approach from the
west due to a potent low pressure system over the northern Plains on
Friday, so the CWA should break free of the wedge with good
southwesterly flow and a building upper level ridge.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 755 PM EDT Friday...
A warm front is generating significant isentropic lift over the
region and driving the development of showers mainly west of the
Blue Ridge as dry air to the east is generally preventing
precipitation from reaching the ground. Mid/upper lapse rates
are sufficient to support some convection as is evidenced by
lightning upstream. Additionally, cold temperatures are keeping
some mixed ptype across Greenbrier and Bath counties.
Believe the best chances for precipitation at TAF sites west of
the Ridge will be through about 06Z, with temperatures up north
will rise enough for an all rain scenario at KLWb by around 03Z.
The best chances for thunder look to be confines further south
and west so will not introduce thunder into the TAFs, though
this may have to be modified based on behavior of upstream
convection. Expect little in the way of appreciable
precipitation at eastern TAf sites.
A cold front then looks poised to move through the region
tomorrow. This will allow for a push of drier air to move in
from the southwest with improving flight conditions. However
westerly winds quickly become gusty, we will settle into an
upslope/downslope pattern by the afternoon with a return to MVFR
and some scattered showers in the west, but hold on to dry VFR
conditions in the east.
Extended Aviation Discussion...
Gusty post frontal northwest winds along with upslope western
mountain snow showers will develop Saturday night and continue
into part of Sunday. Best chances for sub-VFR with snow showers
at KBLF and perhaps KLWB will be Saturday night into Sunday
morning. High pressure building in on Monday should yield VFR
all terminals to start the week. However moisture ahead of
another cold front and associated weak low pressure may arrive
by Monday night, with sub- VFR possible later Monday night into
early Tuesday before improving conditions take shape into
midweek.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...JH/WP
SHORT TERM...PW
LONG TERM...PW
AVIATION...JH/MBS