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LU9DCE > ALERT 20.04.22 19:00z 393 Lines 18833 Bytes #999 (0) @ WW
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Subj: STORM PREDICTION CENTER 20-ABR.22
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Sent: 220420/1830Z 5916@LU9DCE.TOR.BA.ARG.SOAM LinBPQ6.0.22
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SPC Forecast Products Storm Prediction Center en-us None
spc.feedback@noaa.gov (spc.feedback@noaa.gov)
spc.feedback@noaa.gov (spc.feedback@noaa.gov) Wed, 20 Apr 2022
08:55:01 +0000 Wed, 20 Apr 2022 08:55:01 +0000 general 1
SPC Forecast Products
SPC - No watches are valid as of Wed Apr 20 08:55:01 UTC 2022 No
watches are valid as of Wed Apr 20 08:55:01 UTC 2022. Wed, 20
Apr 2022 08:54:06 +0000
SPC - No MDs are in effect as of Wed Apr 20 08:55:01 UTC 2022
No Mesoscale Discussions are in effect as of Wed Apr 20
08:55:01 UTC 2022. Wed, 20 Apr 2022 08:54:05 +0000
SPC Apr 20, 2022 0600 UTC Day 1 Convective Outlook SPC 1200Z Day
1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM
CDT Wed Apr 20 2022
Valid 201200Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
OKLAHOMA INTO SOUTHEAST KANSAS AND EXTREME SOUTHWEST
MISSOURI/NORTHWEST ARKANSAS...
...SUMMARY...
A few supercells are possible late this afternoon and evening from
southeastern Kansas to central/eastern Oklahoma. A few strong storms
may also impact areas west of the Oregon Cascades, accompanied by at
least some risk for severe weather.
...Eastern OK/Southeast KS Vicinity...
An upper-level shortwave trough over the central/southern Rockies at
the beginning of the period will shift east across the Plains during
the afternoon and early evening. Deep-layer flow is not forecast to be
overly strong, with around 30-40 kt expected from around 850-500 mb.
However, vertically veering profiles will support effective shear
magnitudes around 40-45 kt. At the surface, low pressure over central
KS will weaken through the day, with an elongated area of low pressure
extending from central/eastern KS into western/central OK by late
afternoon. A dryline is forecast to develop eastward across central
OK/KS, becoming positioned from southeast KS to just west of the Tulsa
vicinity into south-central OK and then southwestward into central TX.
Southerly low-level flow will transport low to mid 60s dewpoints
northward across eastern OK and southeast KS by peak heating. As
midlevel lapse rates steepen with the approach of the upper trough,
this will aid in moderate to strong destabilization by late afternoon.
This large-scale pattern will generally support a few supercell storms
from late afternoon into the evening.
However, the forecast remains uncertain/conditional. The timing of the
shortwave trough may be sub-optimal for convection. If it ejects east
faster than anticipated, subsidence could limit convective initiation
across much of the Slight risk area. Furthermore, forecast guidance
has become clustered into two camps: 1. convection developing over far
northeast OK/southeast KS into southwest MO. 2. convection developing
from central to northeast OK and spreading southeast into southeast
OK.
Most guidance is consistent in maintaining a stronger cap further
north where temperatures will remain somewhat cooler, and northward
transport of better-quality boundary-layer moisture is even more in
question compared to further south. Any convection that does develop
from southeast KS into southwest MO likely will be contending with
stronger inhibition and a narrower moist warm sector, though will
still conditionally support large hail. Most guidance is consistent in
the dryline developing eastward to roughly the I-35 corridor with a
dryline bulge across northeast OK just west of Tulsa. This area near
the I-44 corridor from near/just east of OKC into northeast OK appears
the most likely area for a couple of supercells in the 22-02z time
frame. Favorably curved low-level hodographs becoming elongated above
3 km will support supercells capable of large hail (some possibly near
2 inches in diameter). Boundary-layer moisture is still expected to be
somewhat shallow, and storms may be higher-based initially, though
some threat will still exist for a tornado or two given adequate
low-level shear and an increasing southwesterly low-level jet during
the evening.
Elevated convection will spread eastward during the late evening
across parts of northern AR and central/southern MO. This activity
will mainly pose a threat for marginally severe hail.
...Western OR...
Southwesterly deep-layer flow will increase as a Pacific upper trough
shifts east toward the Pacific Northwest. Cooling aloft will result in
steep lapse rates and modest destabilization is expected west of the
Cascades. Deep-layer flow will remain mainly uni-directional, however
increasing speed with height will result in moderate effective shear
magnitudes around 25-35 kt. This should support a few organized cells.
Cold temperatures aloft and elongated hodographs suggest hail will be
possible, in addition to locally strong gusts, with stronger
convection. A tornado also will be possible, though weak instability
and modest SRH may temper this potential.
..Leitman.. 04/20/2022
Read more
Wed, 20 Apr 2022 05:51:02 +0000
SPC Apr 20, 2022 0600 UTC Day 2 Convective Outlook SPC 0600Z Day
2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM
CDT Tue Apr 19 2022
Valid 211200Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THURSDAY
AFTERNOON AND EVENING ACROSS PARTS OF NORTHWESTERN OKLAHOMA...CENTRAL
AND EASTERN KANSAS...SOUTHEASTERN NEBRASKA AND WEST CENTRAL
MISSOURI...
...SUMMARY...
A few severe storms are possible across parts of the central Great
Plains late Thursday afternoon into Thursday night, posing a risk for
large hail and perhaps a couple of tornadoes.
...Synopsis...
Recent model runs have trended a bit more amplified with the evolving
mid/upper flow across the U.S. during this period. Large-scale
troughing within the primary belt of westerlies emanating from the
mid-latitude Pacific is forecast to continue progressing inland across
the Pacific coast, with one significant embedded short wave impulse
digging across the California coast before pivoting into the lower
Colorado Valley by 12Z Friday.
Downstream, the latest ensemble output of the various models appears
to develop a more prominent mid-level high across the eastern Gulf
States than earlier runs, with broad ridging also building along an
axis to the northwest of the center, from the lower Mississippi Valley
into the eastern Canadian Prairies. As this occurs, a downstream
trough progressing to the east of the upper Great Lakes appears likely
to dig into the north Atlantic Seaboard by late Thursday night.
The lead mid-level trough will be accompanied by a couple of cold
fronts. This includes a weak initial front, which may advance into
the Mid Atlantic Coast region by 12Z Friday, while a stronger
reinforcing front advances southeast of the lower Great Lakes. As
surface troughing deepens to the lee of the Rockies, the western flank
of the lead front is forecast to shift northward through the central
Great Plains and Middle Mississippi Valley, while the trailing front
stalls across the upper Great Lakes and Upper Midwest into northern
Great Plains.
At the same time, surface ridging, with potentially cool/dry air, will
remain an influence across much of the Southeast and northeastern into
central Gulf of Mexico, with this air tending to slowly advect toward
the northwestern Gulf coast. However, a southerly return flow around
the southwestern periphery of this ridge may still moisten a bit
further inland of the northwestern Gulf coast toward the high plains
to the east of the southern Rockies, and into portions of the central
Great Plains and lower Missouri Valley.
...Central Great Plains and adjacent Missouri Valley vicinity...
A dryline may sharpen across the higher terrain of southwest Texas
through the Texas South Plains and Panhandle vicinity by late Thursday
afternoon. This may provide a focus for at least attempts at
thunderstorm initiation, as moderately large CAPE develops in the
presence of steep lower/mid tropospheric lapse rates. However,
with the dryline likely to be in the process of retreating by early
evening, if not earlier, sustained vigorous thunderstorm development
still seems unlikely.
Enhanced low-level convergence near the dryline and warm frontal
intersection across parts of northwestern Oklahoma into adjacent
southern Kansas seems to provide the best focus for isolated severe
storm development, particularly early Thursday evening as a southerly
low-level jet begins to strengthen from 30-50+ kt. Although mid/upper
flow will be modest in strength, veering of winds with height probably
will contribute to sufficient shear for supercells. These may pose a
risk for producing large hail and perhaps a couple of tornadoes,
before severe hail becomes the more prominent risk as storms tend to
spread north of the warm front, along the low-level jet axis, toward
the lower Missouri Valley vicinity later Thursday evening.
Preceding this activity, storms driven by forcing associated with
lower/mid tropospheric warm advection, spreading across
central/eastern Kansas into the lower Missouri Valley earlier in the
day, may also pose at least some risk for severe hail.
..Kerr.. 04/20/2022
Read more
Wed, 20 Apr 2022 05:52:45 +0000
SPC Apr 20, 2022 0730 UTC Day 3 Severe Thunderstorm Outlook SPC
0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM
CDT Wed Apr 20 2022
Valid 221200Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE FRIDAY
AFTERNOON INTO FRIDAY NIGHT ACROSS MUCH OF THE CENTRAL INTO PORTIONS
OF THE SOUTHERN GREAT PLAINS...
...SUMMARY...
One or two squall lines may evolve across parts of the central Great
Plains Friday afternoon into Friday night, posing a risk for hail and
strong, damaging wind gusts. Additional thunderstorm activity
spreading north of the lower and middle Missouri Valley into parts of
the Upper Midwest may pose a risk for severe hail.
...Synopsis...
Large-scale mid/upper troughing, with several embedded short waves,
appears likely to continue developing inland of the Pacific coast
during this period. Models continue to indicate that this will
include one significant perturbation accelerating northeast of the
lower Colorado Valley into the lee of the Colorado/Wyoming Rockies.
This is forecast to be accompanied by strong surface cyclogenesis from
the lee of the Front Range north-northeastward through central South
Dakota by late Friday night.
This will be preceded by a plume of warm elevated mixed-layer air
advecting through much of the Great Plains and Upper Midwest.
However, models continue to suggest that Gulf moisture return to the
deepening lee surface troughing may begin to become disrupted by
drying associated with low-level ridging building westward toward the
northwestern Gulf coast, beneath a prominent mid-level high centered
over the eastern Gulf States.
While the mid-level ridge axis initially extending to the
north-northwest of this high may gradually pivot across and east of
the Mississippi Valley, the western flank of the broad amplified
ridging may not shift east of the lower Great Plains until late Friday
evening.
...Great Plains into Upper Midwest...
Highest boundary-layer moisture, including surface dew points in the
mid 60s, may become focused along the warm frontal zone shifting
across and north/northeast of the lower and middle Missouri Valley
vicinity, and perhaps in a narrow corridor near the dryline across
west Texas. It appears that the plume of elevated mixed-layer air
will tend to overspread the warm front and provide increasing
inhibition, but this may be preceded by convection supported by warm
advection, which could pose a risk for severe hail.
Stronger/more widespread thunderstorm development seems more likely to
focus near the dryline perhaps as it is overtaken by an eastward
advancing cold front across the central Great Plains Friday evening.
However, to varying degrees, models suggest that this may be preceded
by convective initiation to the east of the dryline, perhaps aided by
a subtle impulse preceding the main upper trough. This remains
unclear, and could considerably impact boundary-layer instability
preceding the developing dryline/cold front convection.
Even so, modestly deep boundary-layer mixing, with CAPE in excess of
1000 J/kg near the dryline, will contribute to an environment with
storms initially posing a severe hail threat, before transitioning to
strong, damaging gusts. This should coincide with an upscale growing
line of storms aided by increasing forcing downstream of the primary
approaching short wave, and southerly 850 mb jet strengthening from
50-70 kt Friday evening.
..Kerr.. 04/20/2022
Read more
Wed, 20 Apr 2022 07:29:00 +0000
SPC Apr 20, 2022 Day 4-8 Severe Weather Outlook Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352
AM CDT Wed Apr 20 2022
Valid 231200Z - 281200Z
...DISCUSSION...
A broad and deep surface cyclone, initially centered over
central/eastern South Dakota at 12Z Saturday, appears likely to
occlude while migrating northeastward into northwestern Ontario
through early Sunday, before weakening more substantively. It appears
that warm sector instability may become confined to a narrow trailing
pre-cold frontal corridor and only rather modest by peak heating
Saturday afternoon. However, given continuing strong lower/mid
tropospheric wind fields along this corridor, latest model output
generally indicates that CAPE may become sufficient to support a
renewed risk for severe thunderstorm development by late Saturday
afternoon and evening across parts of eastern Kansas into central
Iowa.
Later next weekend into early next week, positively tilted mid-level
troughing (lagging to the southwest of the weakening initial short
wave perturbation migrating into eastern Canada) may provide support
for convective development along the lingering surface front slowly
advancing east/southeast of the upper Mississippi Valley and
southeastern Great Plains. However, with low-level wind fields
becoming weaker, and pre-frontal instability likely to remain
seasonably modest and confined to a narrow corridor, the risk for
severe weather seems limited.
Read more
Wed, 20 Apr 2022 08:54:57 +0000
SPC Day 1 Fire Weather Outlook SPC Day 1 Fire Weather
Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0210
AM CDT Wed Apr 20 2022
Valid 201200Z - 211200Z
...CRITICAL FIRE WEATHER AREA FOR MUCH OF NEW MEXICO INTO FAR WEST
TEXAS...
...CRITICAL FIRE WEATHER AREA FOR FAR SOUTHEAST WYOMING INTO THE
NEBRASKA PANHANDLE...
...Synopsis...
Broad/enhanced westerly flow will continue over the western two-thirds
of the CONUS, while a lee surface low develops over far northeastern
New Mexico. The strongest westerly flow will be confined to the
north-central Rockies, within the base of an eastward-advancing
midlevel trough. Farther east, expansive surface high pressure will
move slowly eastward off the Mid-Atlantic coast.
...Southwest into the southern High Plains and Colorado Front
Range... Another day of warm/dry boundary-layer conditions is
forecast across the Southwest into the southern High Plains and
northward along the Colorado Front Range. Diurnal heating/mixing will
encourage widespread 10-15 percent minimum RH, where breezy westerly
surface winds of 15-25 mph are expected. The strongest surface winds
should develop across much of New Mexico into far West Texas, where
Critical highlights remain in place. Along the Colorado Front Range,
locally critical conditions will be possible primarily across
terrain-favored areas, though the localized nature of these conditions
precludes Critical highlights.
...Central High Plains...
Strong downslope warming/drying and diurnal heating will result in
15-20 percent minimum RH across parts of the central High Plains,
where breezy surface winds will develop. From eastern Wyoming into the
Nebraska Panhandle, 25-30 mph sustained west-northwesterly surface
winds (with gusts upwards of 40 mph) will overspread the increasingly
dry airmass. These meteorological conditions, coupled with very dry
fuels, will result in critical fire-weather conditions.
...Western Florida Peninsula...
Along the southern periphery of the expansive surface high pressure,
breezy easterly surface winds near 15 mph will overspread the Florida
Peninsula. Over the western portion of the peninsula, diurnal
heating/mixing could result in a narrow corridor of 35-40 percent RH
coincident with the breezy surface winds. Elevated highlights have
been introduced to account for this localized fire-weather threat.
..Weinman.. 04/20/2022
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
Wed, 20 Apr 2022 07:11:26 +0000
SPC Day 2 Fire Weather Outlook SPC Day 2 Fire Weather
Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0211
AM CDT Wed Apr 20 2022
Valid 211200Z - 221200Z
...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE TEXAS PANHANDLE...
...Synopsis...
An amplified large-scale trough and enhanced southwesterly midlevel
flow will overspread the western states, while a dryline develops over
parts of West Texas. Farther east, high pressure will continue moving
eastward across the western Atlantic waters.
...Southwest into the southern High Plains...
Behind the dryline, breezy southwesterly surface winds will overlap
widespread 10-15 percent minimum RH. Over parts of the Texas
Panhandle, deep boundary-layer mixing into the strong southwesterly
flow aloft will favor sustained surface winds of 20-25 mph with gusts
upwards of 30 mph. These conditions, combined with very dry fuels,
will result in critical fire-weather conditions.
...Central High Plains...
While strong southerly return flow is expected over parts of the
central High Plains, confidence in the overlap of the strong surface
winds and low RH is too low to introduce highlights at this time.
..Weinman.. 04/20/2022
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
Wed, 20 Apr 2022 07:12:25 +0000
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