Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/13/19
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
826 PM MDT Tue Mar 12 2019
As the line of storms continue to shift eastward into Texas, the
tornado threat has diminished. Therefore, the Tornado Watch has been
cancelled for Lincoln, Quay, Chaves, Curry, De Baca and Roosevelt
counties. ZFP out shortly.
.PREV DISCUSSION...523 PM MDT Tue Mar 12 2019...
00Z TAF CYCLE
Upper low circulation over central and srn AZ at 23Z to swing across
nrn and central NM and over sern CO by 13/15Z as it intensifies. Mts
obscured in sct to nmrs MVFR to IFR cigs/vsbys in rain and snow
showers and fog as well as thunderstorms but the precipitation is
expected to begin to decrease in areal coverage aft 06Z becoming more
focused over the higher terrain of the west and north. A line of
thunderstorms moving from west to east over the ern plains at 23Z may
contain isold strong to severe storms with large hail and wind gusts
to 50kt mainly south of Interstate 40 until around 03Z when the
southern portion of the line should exit NM into TX. Very strong sw-
wly winds to develop between 09Z-15Z over ern and srn NM sustained to
35-45kt with gusts to 60kt.
.PREV DISCUSSION...349 PM MDT Tue Mar 12 2019...
Weather conditions will be fickle and unsettled over the next few
days. A potent Pacific low pressure system continues to approach New
Mexico, drawing in copious amounts of moisture ahead of it. This will
continue to lead to scattered to numerous showers and thunderstorms
across northern and central New Mexico through the evening with
strong to severe thunderstorms expected, primarily in the eastern
half of the state. As the Pacific cold front sweeps eastward across
the Land of Enchantment overnight, look for snow levels to lower
while the threat of severe thunderstorms diminishes toward midnight.
Snowfall accumulations will be most significant in the higher
elevations above 8,500 feet, but some light snow could be observed as
low as 6,000 feet through Wednesday morning. A dangerous high wind
scenario will then unfold on Wednesday as the Pacific low rapidly
strengthens as it exits northeastern New Mexico. Strong to severe
wind gusts will inundate much of the state throughout the day
Wednesday with areas along and east of the central mountain chain
observing the highest wind speeds of 60 to 75 mph. Winds will drop
significantly on Thursday, but lingering precipitation could continue
over the northern mountains and surrounding highlands of northeastern
and central New Mexico.
Overall, most of the qualitative and general sensible weather
elements seem to have been well forecasted by preceding shifts, but
this forecast package has plenty of challenges regarding quantitative
precipitation amounts, timing of the lowering of snow, and of course
the finer details of the severe threat in the east this evening.
Pacific low has moved inland over southwestern AZ with mid-
tropospheric pressure heights of about 548 decameters with a healthy
plume of moisture visibly evident on water vapor and other satellite
channels. The strongly diffluent flow ahead of the low is providing
widespread and strong upward forcing amid the juicier and high PWAT
airmass, and low level moisture and instability fields are catering
to scattered to numerous showers and thunderstorms. Cells should
continue turn more numerous and intense through the evening, with the
strongest axis of lift likely preceding the main north-south
baroclinic zone as it overtakes the central mountain chain and
progresses toward the eastern plains. HRRR follows this thinking, and
peering through some of the other noise, the local WRF and other
short term, higher resolution guidance does too. Will keep the Winter
Storm Warnings intact, however have high concerns that not much
impact from snow accumulation will really hit parts of the northwest
highlands (Cuba) and the far upper Rio Grande (Taos).
Much of the eastern plains should be void of precipitation by
Wednesday after daybreak with the focus remaining over the higher
terrain of western and central NM, and more specifically the northern
mountains. Snow levels will begin raising through the late morning
and into the afternoon, creeping up from roughly 6,000 feet up to
7,000 to 8,000 feet. This could allow opportunity for early
cancellations of some of the lower terrain zones in the Winter Storm
Warning. Meanwhile the higher elevations above 8,000 will continue
racking up the snow and blowing snow with the northern high peaks
observing impressive totals over one to two feet. The bigger story
for many zones will be the horrendous winds. Forecast models continue
to show dramatic cyclogenesis (bombogenesis) as the upper low crosses
the northeast corner of NM and enters western KS (about a 21
decameter drop at 500 mb over a span of 12 to 15 hours!). The surface
low is also advertised to be record-breaking as it deepens to 969 mb
per the GFS model for Wednesday afternoon. The flow at 700 mb is
still advertised to be beyond stout with widespread 60 to 80 kt
speeds across NM. Needless to say, many of the High Wind Watch zones
will be upgraded to a warning, and will be doing that with this
package. Blowing dust could be limited by recent precipitation, but
blowing snow will cause further impacts in high terrain areas.
Winds will gradually abate Wednesday night, but will be slower to do
so northeastern NM where the back door cold front will have entered
with a stiff surface pressure gradient due to the proximity of the KS
surface low. Precipitation will also dwindle more Wednesday night
into Thursday, except in the northern mountains and adjacent
highlands. In the wake of the low exiting to the central plains, a
subsequent short wav will keep perturbed flow over northern NM with
orographics staying sufficiently strong to keep northern mountain
snow persistent, occasionally seeping into adjacent highland areas.
Otherwise winds will be notably less through the day on Thursday, but
still windy in far northeastern plains.
In the extended forecast, Friday still appears to be a relatively
down day with just light flurries possible in the northern mountains
while below normal temperatures continue area wide. The next Pacific
low that is set to cross NM on Saturday still appears fairly anemic
with regards to forcing and moisture, but the GFS does introduce
isolated to scattered light precipitation over the state. Another
ill-formed wave could move over the state by Monday of next week.
A broad upper level low pressure system centered south of Phoenix
this afternoon will migrate northeastward across NM for the
remainder of this afternoon and tonight with widespread wetting
precipitation in the form of rain showers, thunderstorms and
mountain snow. Some storms will be capable of producing strong wind
gusts over 60 mph and large hail, especially east of the continental
divide. A Pacific cold front will cross with a wind shift out of the
west and southwest this afternoon and evening. The front will drop
the snow level down to around 6500 feet, but accumulations will
generally remain above 7000 feet with several inches above 8000
Wednesday, winds will become very strong as a surface low bombs out
in eastern CO with record breaking low pressure for that area.
Meanwhile, the jet stream will cross southern NM as a secondary
shortwave trough crosses the state from the northwest. West wind
gusts from 50 to 60 mph will be common, with a broad area of
damaging wind gusts around 75 mph expected across much of the east
central and southeast plains. Winds will weaken gradually with
sunset, while remaining hazardous through the evening, and even into
Thursday behind a back door cold front across the northeast corner
of NM. Accumulating snow is forecast to linger through Wednesday
evening in the northern and western mountains, where the 24 hour
snow accumulations (tonight through Wednesday night) should reach
several inches to near 1 foot, except over 18 inches in the northern
mountains above 8500 feet.
The chance of precipitation will linger over parts of the state
Thursday through the end of the week as three additional shortwave
troughs cross in succession. None of them look very strong, but
portions of the mountains could receive wetting accumulations. Areas
of poor ventilation will also be expected.
High Wind Warning from 3 AM Wednesday to midnight MDT Wednesday
night for the following zones... NMZ521>524-526-539.
High Wind Warning from 6 AM to 9 PM MDT Wednesday for the following
High Wind Warning from 9 AM Wednesday to 6 AM MDT Thursday for the
following zones... NMZ527-530.
Winter Storm Warning until midnight MDT Wednesday night for the
following zones... NMZ502>504-508-511.
Wind Advisory from noon to 6 PM MDT Wednesday for the following
Winter Storm Warning until midnight MDT Wednesday night for the
following zones... NMZ510-513-514.
Winter Storm Warning from midnight tonight to midnight MDT
Wednesday night for the following zones... NMZ512-515-516.
Area Forecast Discussion
National Weather Service Denver/Boulder CO
930 PM MDT Tue Mar 12 2019
Issued at 930 PM MDT Tue Mar 12 2019
A little more detail regarding precipitation rates, there are very
large hourly rates expected, and this is back up in the latest
HRRR runs. These are not typically seen here with hourly rates of
0.20 to 0.25 inch per hour liquid equivalent (while snowing).
That may lead to a very quick degradation of travel conditions
from wet roads to slush and snow, and whiteout conditions!
UPDATE Issued at 911 PM MDT Tue Mar 12 2019
...POWERFUL WINTER STORM WINDING UP THIS EVENING...
...BLIZZARD STILL ON TRACK FOR MUCH OF NORTHEAST COLORADO
WEDNESDAY INTO WEDNESDAY NIGHT...
The latest satellite imagery shows the powerful winter storm
moving northeast across Arizona. Transverse banding on the IR
imagery is showing just how strong this system is, and is a good
indicator of strength and heavy precipitation. Latest RAP QG
analysis shows deep pressure falls and 40 decameter/12 hour falls,
and surface pressure drops of 7-8 mb/3 hours. Very strong
cyclogenesis is underway and will continue through Wednesday. It
is being fueled by very strong thermal advection, a coupled jet
basically creating a vacuum, and the strong vorticity advection
with the approaching upper level low. Scattered showers and even a
couple thunderstorms were already developing well ahead of the
best lift. These will become more numerous overnight.
With regard to the forecast details, if anything there has been a
slight westward trend to the heaviest precipitation over the last
12 to 18 hours. This puts the I-25 Corridor under greater risk of
heavier snowfall. However, there is still the downslope component
to offset some of this threat, so we`ll keep all the highlights
the same for now, with Blizzard Warnings anywhere east of I-25.
That could change with an ever slight westward/upslope shift yet.
Just a matter of miles could make all the difference. The
current Blizzard Warning includes the eastern half of metro
Denver and DIA, and the Palmer Divide/Douglas County, and all
points to the east. The slight westward shift could lead to a
little less snow total over the far northeastern corner of the
state. Whatever the snow amounts will be, the big concern is the
amount of wind in combination with the snow. 24 hour pressure
falls reach bomb status by 21Z tomorrow, just an indicator of the
intensity of this surface low pressure system. Checking the NAEFS
30 year return intervals on 700 mb wind speeds (70-75knots) we are
near 30 year return intervals (something that occurs once every
30 years). Thus, we`re looking at an extreme event, with gusts to
60-75 mph expected. Forecast soundings would also back those gusts
up, with any mixing from snowfall bringing that momentum transfer
to the ground.
ALL IN ALL, A VERY DANGEROUS BLIZZARD is shaping up for areas
just east of I-25 Wednesday afternoon into Wednesday evening.
We`ll continue to closely monitor the potential west of I-25.
Don`t travel if you don`t have to! Travel conditions may change
very rapidly Wednesday morning into Wednesday afternoon, with road
closures, power outages, and zero visibility in these powerful
Finally, we are still a little concerned with temperatures and
local downslope effects, but those details are extremely hard to
work out at this point given the heavy precipitation rates and
significant cooling of the column through melting. Some models
like the NAM would argue for a 6-7 AM changeover along the I-25
Corridor, but most would suggest closer to 9-11 AM which agrees
with the present forecast. This changeover will need to be
watched carefully as just an hour or two difference in the heavy
rates could bring 3-4 inches more, or 3-4 inches less snow to the
.SHORT TERM...(This evening through Wednesday)
Issued at 339 PM MDT Tue Mar 12 2019
For tonight, airmass will be unstable ahead of the approaching
storm system. Lapse rates from 300-600mb will be 7-9 C/km. This
combined with the lift from the approaching storm is expected to
produce scattered showers and isolated thunderstorms from late
this afternoon through this evening. Precipitation turns into a
more widespread rain/mountain snow event late tonight as synoptic
lift takes hold. It will remain warm through the night with
snowfall limited to the higher foothills and mountains. Rain will
continue into Wednesday morning. As the surface low deepens over
southeast Colorado, cold air gets pulled into northern Colorado.
This cold air rapidly spreads south and east changing the rain to
snow. By noon, precipitation should be all snow expect for far
The blizzard is still on track for northeast Colorado on
Wednesday. Latest trends with the models have been slightly
stronger with the surface low, slightly slower, and a little west.
This will be a very strong and quick hitting storm with blizzard
conditions lasting 4-8 hours from late Wednesday morning into
Wednesday evening. For the Denver area, conditions quickly
deteriorate late morning, around 10am when rain changes to snow.
Most of the models have been showing lower snowfall amounts west
of I-25 due to north-northwest downslope winds. Kept snowfall
amounts a little higher than these models because not all the
models show this. Latest 12Z ECMWF shows higher amounts against
the foothills and north of I-70, if this pans out, will likely
need to upgrade to a Blizzard Warning due to the longer period of
near zero visibilities.
Lowest surface pressure from the RAP and ECMWF models show the
low bottoming out at 973mb over northwest Kansas. This low of
surface pressure is in the range of category two hurricanes.
Strong winds are nearly certain given how strong the low will be.
Wind gusts of 60 to 75 mph are expected over eastern Colorado.
Localized higher gusts will be possible. Strong winds will also be
possible west of I- 25, which it is usually sheltered from the
strong north winds. Here gusts of 40 to 60 mph will be possible.
Given these strong winds and expected snowfall, widespread near
zero visibilities are expected over northeast Colorado late
Wednesday morning through Wednesday evening.
Snowfall amounts are expected to greatly vary due to
upslope/downslope effects. For areas east of I-25 where the best
lift from the low will be, expect 5 to 10 inches of snow with
locally higher amounts east of the Denver area. West of I-25,
snowfall amounts are forecasted to be 3-7 inches. Lower amounts
are due to the downslope north-northwest winds. Many of the
mountains will do well with this storm with 8 to 16 inches
expected. Airmass will be unstable over northeast Colorado
Wednesday morning and early afternoon with surface based CAPE from
the RAP model up to 500 J/kg, so thunder snow will be possible
across the area. This will help with higher snowfall amounts as
Travel will become very difficult to impossible along and east of
Interstate 25 late Wednesday morning and Wednesday afternoon.
This will be due to near zero visibility and snow accumulating on
the roadways. When rain changes to snow, the snow will be wet and
likely stick to power lines and tree branches. Broken branches and
power lines will be possible because of the strong winds and
weighted down branches and power lines.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 339 PM MDT Tue Mar 12 2019
After all of the action during the day tomorrow, Wednesday evening
will begin the process of winding down. Gusty winds should still
be in force early in the evening along with some lingering snow.
Snow intensities will be decreasing through the evening, and only
the eastern plains should be seeing any snowfall after midnight.
As the surface low moves off and pressure gradients relax after
midnight, winds will begin to taper off.
The rest of the week will see northwesterly flow aloft continue
over the state with scattered snow showers in the mountains
through Thursday night. Upper level ridging will dominate the
weather over the weekend with dry weather across the forecast
area. Temperatures will be gradually moderating through the
beginning of next week, but will be remaining cooler than normal.
Next Tuesday may see an upper trough rotate over the state from
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 911 PM MDT Tue Mar 12 2019
...SIGNIFICANT AVIATION IMPACTS FROM WEDNESDAY`S BLIZZARD...
Scattered showers developing as expected, and they will become
more numerous through the overnight hours. Rain will become
widespread and change to a heavy, wet, wind driven snow most
likely in the 15Z-17Z time frame Wednesday. Heavy snow, strong
winds, and blowing snow will continue at KDEN and the Denver area
17Z-22Z Wednesday with extended period of visibilities less than
a quarter mile are expected, and this may last through about 02Z
depending on how much snow falls. Extremely strong winds expected
to develop with the onset of snow, with 30-35 knots sustained
winds with gusts to 50-60 knots expected during the heavy snow.
Considerable blowing snow. conditions slowly improve with less
snow and a slow decrease in winds 02Z-06Z Thursday.
Blizzard Warning from noon Wednesday to noon MDT Thursday for
Winter Storm Warning until 6 AM MDT Thursday for COZ035.
Winter Storm Warning until noon MDT Thursday for COZ033-034.
Winter Storm Warning from 10 AM Wednesday to midnight MDT
Wednesday night for COZ036-038-039.
Blizzard Warning from 10 AM Wednesday to midnight MDT Wednesday
night for COZ040-041-043.
High Wind Warning from noon Wednesday to 6 AM MDT Thursday for
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1157 PM EDT Tue Mar 12 2019
High pressure ridge will maintain VFR conditions throughout the
overnight. Ascent ahead of vorticity max tracking through the
northern Great Lakes tonight and very strong warm advection along
return flow surge will support rapid expansion of low cloud and
precipitation into Southeast Michigan after 10Z this morning.
Greatest synoptic scale forcing will pass to the north of the area.
With a veered wind profile over Southeast Michigan, expecting the
area to remain in a anticyclonic flow trajectories. This will cause
more of a glancing shot from the precipitation. Maintained the
inherited VFR category of light rain during the late morning/early
afternoon. Shortwave ridge amplification during the late afternoon
will support a loss of cloud deck ahead of the approaching storm
For DTW...High pressure and antecedent low level dry air will
inhibit rain showers until 16Z. Model data trends have been moderate
in the delay of precipitation onset. A later timing of the
precipitation further limits any potential for freezing rain
.DTW THRESHOLD PROBABILITIES...
* High in precipitation fall as all rain Wed morning.
* Moderate in ceilings below 5000 ft Wednesday morning and
Issued at 326 PM EDT Tue Mar 12 2019
Area of surface high pressure centered over Ohio today has lead to a
sunny day with dry air extending from the surface to 550mb. PWAT on
the morning KDTX sounding was only 0.16 inches and dewpoints at the
surface are around 20F this afternoon. Southwesterly winds around
the high with full mid March sun has allowed temps to rise into the
low 40s. Conditions begin to change this evening with mid/high
clouds streaming into the area down stream of the storm system that
will affect the region through the mid week period.
A strong northern stream jet diving down the west coast will phase
with a cutoff low over southern California tonight into Wednesday
causing rapid cyclogenesis in the lee of the Rockies over the
Central Plains. This surface low will quickly deepen to 980mb or
more by late Wednesday before then weakening and occluding as it
lifts northeastward through the Midwest late Thursday and Thursday
night. This system will present a few opportunities for showers and
thunderstorms between tonight and Friday morning as waves of deeper
moisture and forcing are released out of the trough.
First chance of precipitation will come late tonight as a lead
shortwave rounds the top of the ridge through the northern Great
Lakes. Aided by strengthening low level jet and broad isentropic
ascent showers will spread across the northern part of the state
tonight. Question is how far south into lower MI do the showers
expand? Dry low levels and lack of jet support should keep most of
the area dry tonight, an outcome now supported by the NAM, NAM3KM,
ARW, NMM, GFS, and EURO. RAP and HRRR still holding onto a lead
batch of showers with the leading edge of the theta e advection
tonight. Lowered pops across the south but held onto pops across Mid
MI prior to 12Z Thursday.
The ridge amplifies early Wednesday as the system draws nearer so a
good portion of the east and south could remain dry into the
afternoon. The ridge axis then folds through lower MI later in the
day allowing deeper moisture to spread over the area for the
overnight. A band of showers will likely lift through ahead of the
occluded front with most of the activity still elevated with the
surface fronts still lagging to the southwest. Strong low level jet
exceeding 50 knots will lift into southern MI during this time with
diffluence aloft and upper level jet pushing 100 knots. Elevated
showers with embedded thunderstorms will be possible through the
Thursday morning hours.
Could see a lull for a few hours in the wake of the morning activity
as the low level warm sector slides through SE MI. With strong low
level jet in place (50 knots down to around 4kft possibly) and warm
mixed layer lifting through the area, could see some strong
southwesterly winds in the afternoon Thursday. Though models have
been supporting higher gusts Thursday it should be noted that local
probability graphics show a decreasing trend in likelihood of seeing
wind gusts in excess of 40 mph. A several hour period with gusts of
30-40 mph seems reasonable at this point. Caveat to that will be if
any showers can persist or afternoon redevelopment of showers mixes
down the stronger winds. Strong southwesterly warm air advection will
help temperatures climb into the 60s for most locations Thursday
steepening low level lapse rates. CAPE values of a few hundred j/kg
may aide in the development a broken line of storms moving across
lower MI. Strong winds will be the primary threat with any storms or
stronger showers as the low level jet will still be strong. Dry slot
surging into the area overnight will help shut off the showers for
most of the area overnight.
The low pressure system will continue departing to the northeast
Friday with lingering breezy conditions through much of the day.
Trailing northern stream shortwave energy will dive southeast behind
the departing surface low from the upper Midwest and promote at
least widely scattered shower activity during peak daytime heating.
Temperatures warming into the 40s will result in any precipitation
falling as rain. Cool and relatively dry northwest flow will then
setup across the Great Lakes for the weekend as temperatures settle
back below average into the 30s. Weakening shortwave energy diving
southeast through the northwest flow will attempt to squeeze out
widely scattered rain/snow showers late Sunday before broad and dry
high pressure sets up across the region to start next week. As weak
return flow sets up around the high early next week, temperatures
will begin to slowly moderate back towards normal for mid-March
The departure of high pressure to the east tonight and the slow
approach of a low pressure system will establish a prolonged period
of south-southeast winds across the lakes Wednesday into Thursday
night. Strong low level warm air transport across the icy lakes will
support strong stability and will thus keep wind speeds largely in
check. The strength of the gradient alone may however support a few
gusts up to 25 knots on Lake Huron Thursday. The passage of the sfc
low to the northeast of the region will drive a cold front across
the lakes on Friday and will result in a veering of the winds to the
west-northwest. Post frontal cold air advection may support a few
gusts up toward 30 knots Friday.
The approach of a slow moving low pressure system on Thursday will
provide a good chance for at least a couple intervals of showers
with a few thunderstorms late Wednesday night into Thursday night.
Total forecast rainfall amounts are expected to range from a quarter
inch to three quarters of an inch. Mild air will be driven into the
area Wed into Thursday with this system. This will result in a
melting of the snowpack across Central Lower Mi, impacting the
Tittabawassee River basin. So despite relatively low rainfall totals,
the Tittabawassee (and in thurn Saginaw) Rivers are forecast to
approach flood stage this weekend.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1042 PM CDT Tue Mar 12 2019
Scattered showers have recently developed along and east of
Interstate 35. These should remain just showers as there is a strong
cap beginning at around 800 mb which should suppress any further
vertical development into thunderstorms. Scattered showers should
continue through the overnight period for the I-35 corridor region.
Southeasterly winds continue to ramp up out ahead of this strong
system, with sustained winds as high as 20 to 25 mph and gusts up to
30 to 35 mph. This should also continue through the overnight period
out ahead of the eventual line of storms.
Speaking of which, the line of thunderstorms currently reside (as of
10:40 pm Tuesday) from near Lubbock south into the Big Bend. A few
discrete cells are tying to form out ahead of this line, but for now
remain north of Val Verde County. This line will continue to move
east overnight and into the morning hours of Wednesday. The best
chance for severe weather will be across the southern Edwards Plateau
(Val Verde and Edwards Counties) in which all severe weather hazards
will be in play. Accordingly, a Tornado Watch has recently been
issued for Val Verde County until 5 AM Wednesday morning.
Subsequent convective watches (most likely of the Severe
Thunderstorm variety) may be issued further east later tonight as
the storms progress eastward, in which strong winds will become the
primary hazard. The line of storms should weaken as they progress
east due to decreasing instability and a more stable boundary layer.
There is still some disagreement on the timing of the line. The HRRR
and Texas Tech WRF bring the line through slower, reaching the I-35
corridor in the 7 to 9 am time frame. The NAM Nest is quicker,
bringing it through in the 5 to 7 am time frame. More than likely,
the line of storms will be sub severe by the time it reaches Austin
and San Antonio. However, there will be plenty of low level and deep
layer wind shear, so if the line of storms can generate a solid cold
pool and can manage to sustain itself well enough as it reaches the
I-35 corridor, severe weather will be in play, primarily in the form
of some isolated strong wind gusts up to 60 mph.
The line of storms will continue to weaken as they track east of
I-35. They should be completely out of the region by late
morning/early afternoon, in which skies will clear and gusty
west/southwesterly winds will take hold.
.PREV DISCUSSION... /ISSUED 630 PM CDT Tue Mar 12 2019/
All sites VFR with gusty southeast winds. Gusts as high 34kts has
been observed at KAUS, though will maintain 22-25kts in the TAF. A
line of strong storms are expected to move through the area overnight
and into the morning along a Pacific front. Timing for storms to
reach KDRT around 08Z and for terminals along I-35, 11Z.
PREV DISCUSSION... /ISSUED 359 PM CDT Tue Mar 12 2019/
SHORT TERM (Tonight through Wednesday Night)...
Upper low over Baja region will be moving east and then northeast
across the southern plains over the next 24 hours. Water vapor
imagery shows strong diffluence ahead of the system and associated
lift is already occurring over northern Mexico. As this system
approaches, our cwa has transitioned to a warm sector, bringing the
needed instability to support convection later tonight.
A foggy start of the day has improved drastically as the warm front
pushed north through all the cwa and this unstable and breezy
atmosphere will remain in place overnight. Will continue small pop
for the late afternoon and evening for showers, and maybe isolated TS
out west. A few of the HRRR runs are starting to show some pre-
squall line sh/ts come across the Rio Grande near DRT in the late
evening hours. Will have to watch for severe threat with this
activity before the forecast squall line associated with the pacific
front/dry line pushes into the CWA after midnight. Looks like the far
western Edwards Plateau will be under the threat of strong/severe
storms between midnight to 3AM...Hill Country 3-6 AM...pushing into
the I-35 corridor around morning rush hour...6-10 AM, and 8 AM-noon
east of I-35, and along I-10. Once the line passes AUS/SAT...mid the
late morning clearing with the POP ending quickly west to east as
large dry slot moves in from the SW and wraps into a surface low over
the TX/OK panhandles. Severe parameters are best out west, and with
the storms coming into AUS/SAT region around dawn which is
historically the most stable time of the day, widespread severe
weather is not expected over our eastern areas.
Lower humidities behind this system and some gusty west winds will
bring some near critical fire conditions to the far west and Rio
Grande Plains both Wed and Thu. With the downsloping west winds on
Wednesday, temps will still warn into the mid 70s to lower 80s.
Mainly 50s Wed night.
LONG TERM (Thursday through Tuesday)...
As we get into Thursday, the upper low and surface low
will be moving east into the upper MS valley with cool air filtering
down into Texas on the back side. Will see an associated cool down
with respect to day and night temps...highs mainly in the 60s and
lows in the 40s. A upper zonal flow will keep pop out of the
extended forecast. Long range models do show an upper low coming into
the southern Rockies but with surface ridging still in place, dont
expect enough moisture return to lead to any significant pop...just
an increase in clouds. A slow warmup may be in store early next week
but the models are keeping a stubborn surface ridge axis over the
state not allowing for deeper southerly flow until beyond the 7 day
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 78 51 71 43 / 80 70 10 0 0
Austin Bergstrom Intl Airport 62 78 51 71 43 / 70 70 10 0 0
New Braunfels Muni Airport 62 79 52 72 43 / 70 60 10 0 0
Burnet Muni Airport 55 75 47 65 40 / 90 50 0 0 0
Del Rio Intl Airport 57 80 51 73 46 / 70 - 0 0 0
Georgetown Muni Airport 59 77 49 67 41 / 80 80 10 0 0
Hondo Muni Airport 61 80 51 75 45 / 80 10 10 0 0
San Marcos Muni Airport 62 79 51 72 43 / 70 70 10 0 0
La Grange - Fayette Regional 66 77 55 72 44 / 50 70 20 10 0
San Antonio Intl Airport 61 79 53 73 44 / 80 50 10 0 0
Stinson Muni Airport 63 81 54 75 46 / 70 40 10 0 0
Area Forecast Discussion
National Weather Service Grand Junction CO
549 PM MDT Tue Mar 12 2019
.SHORT TERM...(Tonight through Wednesday night)
Issued at 100 PM MDT Tue Mar 12 2019
A major early spring storm continues to affect the Four Corners
region this Tuesday afternoon. Over the next several hours, the
primary focus will continue to be on southwest Colorado and far
southeast Utah with regard to the thunderstorm and convective threats.
The past several runs of the HRRR continue to show remarkable
consistency in the development of strong to possibly severe
convection over far northeast New Mexico, which eventually moves
north into southern Colorado. SPC mesoanalysis as of 18z this
afternoon indicates over 500 j/kg of SBCAPE, around 45 knots of
bulk shear, and SRH values in the 50-100 range. While not
particularly notable in the eastern two thirds of the nation,
these values are cause for alarm west of the Continental divide
above 5000 feet elevation....with small hail, gusty winds, and
heavy rain all realistic threats. Short term CAM guidance
indicates any thunderstorms that do develop will move rapidly
northeast into the Cortez-Durango-Pagosa Springs corridor between
21z and 0z this afternoon. Of particular note will be the heavy
rain threat - much of this region currently has a deep snowpack
and decaying convective downpours could easily result in localized
flooding. This will be especially true in the foothills of the
San Juan mountains, where large rockfalls and debris slides have
already occurred overnight into this morning.
After 0z tonight, the convective threat diminishes rapidly. Focus
will then turn to the potent shortwave trough diving in through
the Great Basin, behind the main area of low pressure moving east
across New Mexico. 500mb vorticity progs from 0z tonight through
tomorrow afternoon depict a spectacular phasing of these two
systems, resulting in explosive cyclogenesis over the eastern
high plains. Closer to home, impactful weather will include
moderate to heavy snow above 9000 feet in all mountain ranges,
with around 0.5 inches of rain falling in the valleys. Cold air
will eventually filter south and eastward behind this system in
the form of a 700mb thermal boundary, which is expected to lower
snow levels to the valley floors along the US 40 corridor by
early- morning on Wednesday.
In this forecast package, the main changes have been to expand the
winter weather headlines across all of the northwestern Colorado
valley zones, as well as the introduction of an advisory for the
US 50 corridor near Cerro Summit. While surface temperatures will
remain relatively mild (low 30s) in the lowest elevations,
moderate snow rates and plenty of cold air aloft will result in
accumulations of over 3 inches in these locations. Elsewhere, much
of the previous forecast package was retained: snow totals in the
higher terrain have remained consistent in today`s model runs and
no changes were needed.
By Wednesday night, the powerful area of low pressure over the
central high plains will head eastward. Northerly flow on the back
side of this system will keep snow going on all favored northern
facing slopes throughout the central and northern mountain ranges.
700mb temperatures by this time will run in the -12 to -14 range,
resulting in a much lower density snowfall than at the onset of
.LONG TERM...(Wednesday night through Monday)
Issued at 329 AM MDT Tue Mar 12 2019
Classic mid level cyclone will be pounding the Plains with a fully
stacked system and surface low moving toward the occluded stage
by Wednesday evening. This system is so tightly wound by this time
that it appears the trowal will be East of the divide and really
feeding a good frontal band across the High Plains to the Dakotas
where blizzard conditions are looking nasty. What we will have on
our side of the hills is strong cold advection in the lower and
mid levels with PV advection aloft. The deep northerly flow will
be favorable for orographics on north facing slopes and initially
when residual moisture is present...a potential Uncompahgre Gorge
event late Wednesday into early Thursday. Showers are likely to
continue through the day Thursday as instability will be easily
released. Both the GFS and NAM hint at weak mid level low also
developing over the SE San Juan Range as the last part of the jet
moves through Thursday evening. This last push leads to upslope
once again into this region and could easily keep snow going over
CPW through sunrise on Friday. We look to finally get a more
prolonged break in the precipitation so folks can dig
out...literally. Below normal temperatures will hang around in the
wake of this system through Saturday. We then get ridging
followed by WAA and this should bring us back up to near normal
for mid March.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 544 PM MDT Tue Mar 12 2019
Limited vsby and low cigs across the southern TAF airports will
become widespread through the evening hours. Most TAF sites will
see some level of impact by 13/06Z as rain and snow spread across
the region. These impacts will persist through at least Wednesday
evening as this storm wraps up on the East side of the divide.
CO...Winter Weather Advisory until 6 AM MDT Thursday for COZ004-012.
Winter Storm Warning until 6 AM MDT Thursday for COZ003-009-010-
Winter Storm Warning until 6 AM MDT Thursday for COZ018.
Winter Weather Advisory from midnight tonight to midnight MDT
Wednesday night for COZ001-002-005-014.
Winter Storm Warning until midnight MDT Wednesday night for
UT...Winter Weather Advisory until 6 AM MDT Thursday for UTZ023-025.
Winter Storm Warning until 6 AM MDT Thursday for UTZ028.
Area Forecast Discussion
National Weather Service Lincoln IL
850 PM CDT Tue Mar 12 2019
Issued at 850 PM CDT Tue Mar 12 2019
Despite increasing southeasterly flow on the back side of
departing high pressure, the atmosphere has been slow to moisten
this evening. The 00z KILX upper air sounding showed ample dry air
below 700mb, which has thus far prevented much in the way of
measurable precip across central Illinois. Have seen a few
reports of sprinkles reaching the ground along/west of I-55, but
the most widespread precip remains well to the SW across Missouri.
HRRR quickly caught on to this trend and has been consistently
showing a delayed onset to the rain over the past several runs. As
a result, updated the forecast earlier this evening to carry just
chance PoPs across the west until around midnight when the
Missouri precip spreads into the area from the southwest.
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 312 PM CDT Tue Mar 12 2019
Showers will be possible overnight as warm air advection continues
ahead of a strong low pressure system deepening into the central
Plains. With cloudy conditions and steady south to southeast winds
10 to 15 mph temperatures will only fall to the mid 40s.
Warm advection and disturbances embedded in strong southwesterly
flow aloft will continue into Wednesday bringing periods of
precipitation possible, as well as a few thunderstorms by
Wednesday afternoon, followed by the main frontal system late
afternoon Wednesday into Wednesday evening. Highs should reach the
60s, especially south of I-72 as the warm sector reaches this
area. Quite breezy south to southeast winds will develop, over 20
mph with gusts over 30 mph. Showers and thunderstorms should
become most plentiful Wednesday evening.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 312 PM CDT Tue Mar 12 2019
Several hundred J/kg of CAPE look to develop early in the day
Thursday in a narrow warm sector, which will produce a threat for
severe thunderstorms when combined with strong shear. SPC has a
marginal risk of severe thunderstorms, mainly for high wind threat,
Decatur to Bloomington eastward. Combined with south to southwest
winds 30 mph and gust potential 50-60 mph southeast of the
Illinois River, any storms that form should have little trouble
producing severe wind gusts. Temperatures will be quite mild
Thursday, with highs reaching 60 in Galesburg to 71 in
Lawrenceville, before cold advection arrives late in the day
Temperatures will drop back below normal Friday through the
weekend. Mainly dry conditions can be expected this period.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 641 PM CDT Tue Mar 12 2019
Showers are trying to spread into central Illinois from the west
early this evening: however, a dry boundary layer is slowing the
onset of the rain. HRRR continues to delay the rain, with
widespread showers likely holding of until after midnight. In the
meantime, will feature VCSH at all terminals except KDEC/KCMI
through the evening. Have lowered ceilings to MVFR and introduced
predominant showers at KPIA by 05z...then further east at KCMI by
around 11z. Once the overnight/early morning showers come to an
end, the main aviation forecast concern will then shift to the
increasing southerly winds. Forecast soundings and numeric
guidance both suggest gusts reaching 25-30kt from around midday
through the afternoon.
Area Forecast Discussion
National Weather Service Blacksburg VA
856 PM EDT Tue Mar 12 2019
High pressure will remain overhead through Wednesday. After this
high heads offshore during Wednesday night into Thursday, a cold
front should bring the next chance of rain for Thursday night
and Friday. High pressure will return later this weekend.
.NEAR TERM /THROUGH WEDNESDAY/...
As of 856 PM EDT Tuesday...
Little changes were made the forecast tonight, with the biggest
forecast challenges cloud cover and temps. The 00Z RNK sounding
shows the upper levels of the atmosphere, around and above 300
mb, have moistened since 12Z. Also, as an upper level trof
lifts and the mid to upper flow becomes more westerly, an
increase in cirrus clouds should enter the forecast area,
primarily across the mountains, as the 23Z HRRR depicts.
However, the a bigger influence on low temperatures tonight may
be the winds, which will increase across the higher elevations
in the west as the axis of sfc high pressure shifts east of our
forecast area. As a result, bumped up low temps at BLF and
other higher mountain elevation sites. At 00Z (8 PM EDT),
Roanoke is running a few degrees warmer than forecast, but once
valley winds diminish here, temps should fall to near previously
Look for more clouds to emerge from the west before sunrise and
persist into Wednesday as depicted in the MET MOS guidance.
Light south winds should offer some warm air advection during
the day. As a result, highs for Wednesday were nudged slightly
upward but kept well below MAV MOS guidance due to it not
accounting for the cloud cover and consequently being
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 200 PM EDT Tuesday...
The most active weather through the next seven days will
occuring during this portion of the forecast. Temperatures
will continue to trend higher through Thursday in advance of the
approach of a strong cold front. Moisture levels will be
ramping up during the day in advance of this feature on
increasing, deep southwest flow. While the entire area will be
mostly cloudy to cloudy because of this feature, those locations
along and near the crest of the Blue Ridge will experience
isolated to scattered showers thanks to upslope conditions
maximizing in this area. This is expected to start Thursday
morning, and potentially as early as late Wednesday night across
the Northern Mountains of North Carolina. Parts of southeast
West Virginia and neighboring counties of southwest Virginia may
see isolated to scattered showers Thursday afternoon as the
cold front at its associated dynamics draw closer to the
forecast area. Low temperatures Wednesday night will range from
the low 40s to the mid 40s for most of the region. Far southwest
Virginia and parts of the North Carolina Piedmont will be
closer to the upper 40s. Highs on Thursday will reach the mid to
upper 60s for most of the area. The higher elevations will be
closer to the upper 50s to around 60 degrees.
Thursday night the cold front is expected move even closer to the
area, being on our western doorstep by daybreak Friday. Expect
rain showers to progressive increase through the night with
very good coverage for most locations by daybreak Friday. The
one exception may be the far southeastern parts of the region.
Here coverage may still only be scattered early Friday morning.
Thursday night, lows will range from the the lower 50s to the
mid 50s across the mountains with mid to upper 60s over the
Piedmont. Friday, highs will range from the upper 50s to lower
60s over the mountains to the upper 60s to around 70 over the
On Friday morning, the cold front and its associated showers are
expected to progress across the region from west to east. The
associated 850mb front is expected to lag about six hours behind
the surface front. It will be this elevated feature that we
will want to see clear the region before the associated
precipitation ends, and a turn towards a colder northwest flow
begins to invade our region. Timing of this feature will
coincide best with the peak heating of the day across the
eastern half of the region. We will still be offering a forecast
with a slight chance of thunderstorms until the 850mb front is
east of the area. Friday, highs will range from the upper 50s to
lower 60s over the mountains to the upper 60s to around 70 over
By Friday evening, precipitation immediately associated with the
cold frontal passage will be east of the region. However, as
northwest winds increase, look for temperatures to fall quickly.
Upslope flow will switch to western parts of the area where
isolated to scattered rain/snow showers are expected across
parts of southeast West Virginia and neighboring counties of
southwest Virginia. As the night progresses, these will decrease
in number. Low temperatures Friday night will range from the
low to mid 30s across the mountains to around 40 to the lower
40s across the Piedmont.
Confidence in the above portion of the forecast is high.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 230 PM EDT Tuesday...
Some lingering rain/snow showers will be possible across western
Greenbrier County, WV Saturday morning, but these aren`t
expected to last much into Saturday afternoon as drier air
progresses into the region. Dry conditions will continue into
Sunday as surface high pressure moves overhead. A reinforcing
shot of colder air is expected on Monday with the passage of a
shortwave trough moving through the mid-Atlantic and New England
regions. This feature may bring a few more isolated rain/snow
showers into southeast West Virginia and neighboring southwest
Virginia. Low temperatures during this portion of the forecast
will range from the upper 20s to lower 30s across the mountains
most night with low to mid 30s most nights across the Piedmont.
High temperatures will generally range from the upper 40s to
lower 50s across the mountains with low to mid 50s across the
Confidence in the above portion of the forecast is moderate.
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
As of 120 PM EDT Tuesday...
VFR conditions will prevail over our forecast area through
Wednesday as high pressure dominates our weather. Winds will
continue to diminish tonight, then become southeast during the
day Wednesday with most locations at or below 10 knots.
High cirrus clouds will increase on Wednesday, but confidence
remains high that VFR conditions will remain in place at all TAF
sites through at least Wednesday.
EXTENDED AVIATION DISCUSSION...
High pressure should drift offshore during Wednesday night into
Thursday, but VFR conditions should remain throughout that
time. By Thursday night, confidence is increasing that a cold
front will bring the next chance of rain along with MVFR
ceilings and visibilities into Friday. After the frontal
passage, scattered rain and snow showers could be possible in
the western mountains during Friday night into Saturday. VFR
conditions should resume late Saturday into Sunday as high
As of 130 AM EDT Monday...
KFCX Doppler radar in Floyd county will be down for maintenance
March 11-15, 2019.
The WSR-88D Radar operated by NOAA National weather Service in
Blacksburg Virginia will be out of service through
approximately March 15 for the refurbishment of the
transmitter. Although the form, fit and function of the
transmitter will remain the same, old breakers and cables
original to the radar will be replaced with modern fuses and new
cables. This will keep the 20- year- old radar operating
smoothly for another 20 years.
This transmitter update is the second major project of the
NEXRAD Service Life Extension Program, a series of upgrades and
replacements that will keep our nation`s radars viable into the
2030s. NOAA National Weather Service, the United States Air
Force, and the Federal Aviation Administration are investing
$150 million in the seven year program. The first project was
the installation of the new signal processor. The two remaining
projects are the refurbishing of the pedestal and equipment
shelters. The Service Life Extension Program will be completed
in 2022. During the downtime, adjacent radars include KRLX,
KLWX, KGSP, KMRX, KRAX and KAKQ. For direct access to any of
these surrounding radar sites, go to the following web page:
Area Forecast Discussion
National Weather Service San Diego CA
159 PM PDT Tue Mar 12 2019
An upper level trough will move southeast across Nevada tonight,
increasing west winds along the desert slopes and the high desert.
A few showers will develop tonight, favoring the coastal mountain
slopes of Riverside and San Diego County. Dry and warmer
conditions will prevail Wednesday through the weekend with
periodic gusty northeast winds along the coastal mountain slopes
and below canyons and passes. Dry and warm conditions will
continue into at least early next week.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
The storm system that brought rain and significant mountain snow
to Southern California has departed the area into Arizona this
afternoon. This system will continue to move away from the
region while another trough races southeast across Nevada
overnight. West winds will increase ahead of this feature with
strong wind gusts to 55 mph, isolated to 65 mph, along the desert
mountain slopes overnight. Gusts of 30-40 mph are expected over
the high desert, possibly to 50 mph east of Apple Valley.
A few light showers look to re-develop tonight and favoring San
Diego County, but not so much near the coast, more so well inland
towards the coastal mountain slopes and extending to the Riverside
County mountain west facing slopes. WRF and HRRR both show all the
rainfall occurring there. Still, can`t rule out isolated showers
along the coast.
No rain is expected across our northwestern areas, from Orange
County through the NW Inland Empire through the San Gabriels as
well as across the deserts. The most rain will fall along the
coastal mountain slopes of the San Diego County mountains
extending north to the Riverside County coastal slopes. Amounts
there will average near 0.25 inches, but some locales could
receive near a half an inch. The snow level will be at around 6000
feet with max amounts to 1 inch at Mt. San Jacinto.
West winds will crank up along the desert slopes and across the
high desert this evening through early Wednesday morning with
gusts to 55 mph, isolated to 65 mph, forecast at rural desert
slope locales. A Wind Advisory is in effect for these areas this
evening through early Wednesday morning.
Wednesday through Friday will see a moderation in temps under a
mostly clear sky. However, warming will be tempered on Friday due
to a dry shortwave diving southeast and across the area. This
basically acts to keep temps between Thu-Fri status quo.
Temperatures over the inland valleys will be quite cold Thursday
and Friday morning. A clear sky, light winds and dry air should
provide for good radiational cooling (away from the northeast wind
corridors where the atmosphere will stay mixed). This will bring
temps into the 30s with frost potential in and around areas
extending from Corona to Lake Elsinore to Valley Center to
Ramona. Lowered temps across these areas using a GFS- NAM-EC MOS
Global models show heights rising substantially this weekend.
This will lead to further warming Sat-Sun and warmth will continue
through Tuesday under abundant sunshine. The next chance of
precipitation could arrive during the middle part of next week.
122000Z...Coast/Valleys...SCT-BKN clouds with bases 2500-5000 ft
MSL, layered to 12000 ft MSL, through 03Z. Higher terrain will be
obscured with local vis 1 mile or less. Low clouds and -SHRA could
impact TAF locations west of the mtns between 03Z and 12Z Wed with
cigs 1500-2500 ft MSL and local vis 1-3 miles at times. Expect SCT
clouds after 15Z Wed.
Elsewhere, SCT clouds with bases at or abv 10000 ft MSL and
unrestricted vis through tonight.
Increasing winds and building seas, generating hazardous conditions
this afternoon through early Wednesday. A Small Craft Advisory
remains in effect. No additional hazardous marine weather is
expected Wednesday afternoon through Saturday.
CA...Wind Advisory from 6 PM this evening to 8 AM PDT Wednesday for
Apple and Lucerne Valleys-Riverside County Mountains-San
Bernardino County Mountains-San Diego County Deserts-San
Diego County Mountains-San Gorgonio Pass Near Banning.
PZ...Small Craft Advisory until noon PDT Wednesday for Coastal Waters
from San Mateo Point to the Mexican Border and out to 30 nm-
Waters from San Mateo point to the Mexican Border Extending
30 to 60 nm out including San Clemente Island.
For frequently asked questions about the Area Forecast Discussion