RSS Mesoscale Discussions from Storm Prediction Center
WW 410 SEVERE TSTM AL FL GA 201800Z - 210200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 410
NWS Storm Prediction Center Norman OK
200 PM EDT Thu Jun 20 2019
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
southern Alabama
northern Florida Panhandle
southern Georgia
* Effective this Thursday afternoon and evening from 200 PM until
1000 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Storms are expected to increase in coverage and intensity
this afternoon posing a risk for damaging wind and hail as they
spread east and southeast through the Gulf Coastal States.
The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 10 miles south of
Brunswick GA to 80 miles west southwest of Selma AL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU0).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 408...WW 409...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
29035.
...Dial
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WW 409 SEVERE TSTM NC VA CW 201750Z - 210200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 409
NWS Storm Prediction Center Norman OK
150 PM EDT Thu Jun 20 2019
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Central North Carolina
Central and Eastern Virginia
Coastal Waters
* Effective this Thursday afternoon and evening from 150 PM until
1000 PM EDT.
* Primary threats include...
Widespread damaging wind gusts to 70 mph likely
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
A tornado or two possible
SUMMARY...Thunderstorms will organize over central North Carolina
and spread eastward across the watch area this afternoon and
evening. Damaging winds are expected with the strongest cells,
along with some risk of hail.
The severe thunderstorm watch area is approximately along and 85
statute miles east and west of a line from 15 miles southwest of
Fayetteville NC to 40 miles north northwest of Richmond VA. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU9).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 408...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
27030.
...Hart
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WW 408 SEVERE TSTM GA NC SC CW 201740Z - 210200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 408
NWS Storm Prediction Center Norman OK
140 PM EDT Thu Jun 20 2019
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
norhtern through Central Georgia
southern North Carolina
South Carolina
Coastal Waters
* Effective this Thursday afternoon and evening from 140 PM until
1000 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Scattered large hail events to 1.5 inches in diameter possible
SUMMARY...Thunderstorms are expected to increase in coverage and
intensity this afternoon over a large part of the Southeast States
posing a risk for scattered damaging wind and hail.
The severe thunderstorm watch area is approximately along and 105
statute miles either side of a line from 45 miles north northeast of
Florence SC to 50 miles west southwest of Macon GA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
29035.
...Dial
Read more
WW 0410 Status Updates
STATUS FOR WATCH 0410 HAS NOT BEEN ISSUED YET
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WW 0409 Status Updates
STATUS FOR WATCH 0409 HAS NOT BEEN ISSUED YET
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WW 0408 Status Updates
STATUS FOR WATCH 0408 HAS NOT BEEN ISSUED YET
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MD 1161 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR -CENTRAL NEW YORK SOUTHWARD TO THE DELMARVA
Mesoscale Discussion 1161
NWS Storm Prediction Center Norman OK
1253 PM CDT Thu Jun 20 2019
Areas affected...-Central New York southward to the Delmarva
Concerning...Severe potential...Watch possible
Valid 201753Z - 202000Z
Probability of Watch Issuance...40 percent
SUMMARY...Thunderstorms are expected to increase in coverage and
intensity this afternoon ahead of an approaching shortwave trough.
The strongest storms will primarily pose a threat of damaging wind
gusts, and trends will be monitored for the necessity of a watch.
DISCUSSION...Despite developing in an environment with limited
instability, thunderstorms across central New York have shown some
signs of organization, likely aided by the convectively enhanced
midlevel circulation moving across northern New York. Ahead of this
convection into far south-central New York and eastern Pennsylvania,
visible satellite imagery indicates pockets of heating allowing for
some destabilization. As such, additional warm sector thunderstorms
are expected to develop, and given the sufficient deep-layer shear,
there will be some potential for organized storm modes. These
storms would primarily pose a damaging wind threat through the
afternoon and early evening hours. At this time, there is
uncertainty whether storm coverage and intensity will necessitate
watch issuance, but convective trends will be monitored.
..Jirak/Hart.. 06/20/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OKX...ALY...PHI...BGM...CTP...LWX...
LAT...LON 40517809 41707730 42387607 42807535 43057452 43157378
42997339 42507324 41567367 40407427 39527482 38657535
38947735 39257793 40517809
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1116 AM CDT Thu Jun 20 2019
Valid 201630Z - 211200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
VA TO EASTERN GA TODAY...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE
NORTHERN/CENTRAL HIGH PLAINS TO THE LOWER MO VALLEY...
...SUMMARY...
Swaths of damaging winds are most likely from southern Virginia to
eastern Georgia this afternoon. The risk for very large hail with a
few tornadoes exists across parts of the Mid-Missouri Valley this
afternoon into early evening. Otherwise, scattered severe storms are
expected across a broad portion of the central and northern Great
Plains, and over the eastern states.
...Southeast and Mid Atlantic States...
A progressive shortwave trough is evident in morning water vapor
imagery over AL, with other minor MCVs farther north over east TN
and WV. These features will track eastward today across much of the
Southeast states and Mid Atlantic region. Strong daytime heating is
occurring over this region, where dewpoints in the 70s will yield
afternoon MLCAPE values of 1000-2000 J/kg. Strong westerly flow
aloft, steep low-level lapse rates, and favorable large-scale
forcing will combine for an active strong/severe thunderstorm event
for this region. Multiple lines and clusters of storms will
traverse the area this afternoon and evening, posing a risk of
damaging winds and some hail.
...Northern PA/NJ/NY into New England...
Persistent cloud cover is limiting heating/destabilization from
northern PA/NJ northward into New England. Despite the limited
thermodynamic environment, model guidance and recent radar trends
suggest the potential for scattered afternoon thunderstorms.
Forecast soundings show very favorable vertical shear profiles for
organized or even rotating storms capable of gusty winds and perhaps
a tornado. However, given the weak CAPE profiles, it appears that
the severe risk in this area will remain widely spaced and primarily
marginal. Nevertheless, have extended the SLGT risk area northward
into central NY ahead of ongoing strong activity.
...NE/IA/KS/MO...
A well-defined shortwave trough is moving across SD/NE this morning.
12z model guidance provides continued confidence that a cluster of
intense storms will continue to develop/evolve with this feature
over northeast NE and track southeastward into parts of IA/MO/KS.
These storms may produce very large hail and damaging winds. This
corridor may require an upgrade to ENH at 20z once mesoscale details
become more clear on the evolution of the cluster of storms.
...Northern and Central High Plains...
Strong heating is occurring today from southeast MT into eastern WY
and far eastern CO, where dewpoints in the mid 40s to lower 50s and
steep mid-level lapse rates are present. Scattered thunderstorms
are expected to develop along this axis by mid/late afternoon -
spreading eastward through the evening. Forecast soundings show
favorable vertical shear profiles for a few supercells capable of
large hail and damaging winds. An isolated tornado or two is also
possible. The activity which forms in eastern CO/western KS appears
to have the best chance of persisting deep into the evening and
spreading farther east across KS.
..Hart/Jirak.. 06/20/2019
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1239 PM CDT Thu Jun 20 2019
Valid 211200Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE NORTHERN AND CENTRAL PLAINS ACROSS THE MID AND LOWER MISSOURI
AND MID MISSISSIPPI VALLEYS...
...SUMMARY...
Severe thunderstorms are possible Friday across parts of the
northern and central Plains, southeast across the middle and lower
Missouri and mid Mississippi Valleys, to the Tennessee Valley
region.
...Northeast Colorado vicinity...
As a cold front shifts slowly southward across the central High
Plains, heating of the moist post-frontal airmass across northeast
Colorado will occur. Coupled with ascent ahead of the advancing
upper system, focused at the surface by post-frontal upslope flow
over the Front Range/Palmer Ridge, afternoon storm development is
expected.
With low-level easterly/east-northeasterly flow
veering/strengthening with height to southwesterly, shear will
support supercell evolution. Along with large hail, locally
damaging winds will be possible, along with a couple of tornadoes.
The storms should grow upscale as they shift off the higher terrain
through the evening, cross portions of Nebraska and northern Kansas,
with continued severe risk well into the evening hours.
...Mid Missouri Valley and surrounding areas...
While prior convection -- shifting southeastward across
Missouri/Iowa early in the period -- is expected to stabilize the
airmass over the Mid Missouri Valley initially,
heating/destabilization is expected in the wake of the storms.
Though convective development will likely be hindered through much
of the day, a combination of isolated development near the weak
surface low/warm front expected over the area by late
afternoon/early evening, and the later advance of convection from
the west, should result a sizable area of scattered storms.
With favorably veering flow with height providing ample shear given
moderate CAPE, organized/supercell storms are expected initially.
Eventually, the approach of convection from the west should result
in MCS development across this area, aided by evening development of
a southerly low-level jet. Large hail and damaging winds will
remain possible into the evening, along with risk for a couple of
tornadoes.
...Portions of the Dakotas and into Minnesota...
Afternoon development of thunderstorms is expected along an arcing
trough from the eastern Dakotas into northeast Nebraska, with
isolated storms perhaps occurring as far northwestward as northwest
North Dakota. As southwesterly flow aloft increases gradually ahead
of the advancing upper trough, atop low-level
southerly/southeasterly flow, organized/rotating storms are
expected. Hail will likely be the predominant risk, though locally
damaging winds and a couple of tornadoes may also occur, with risk
lingering into the evening before diminishing diurnally.
...Mid Mississippi/Tennessee Valley region...
Though substantial differences exist across the range of models with
respect to location, timing, and southeastward sustenance, a general
consensus suggests that widespread convection will be ongoing across
the Iowa/Missouri vicinity at the start of the period, near the
northwest-to-southeast surface front and sustained by a
veered/southwesterly low-level jet. Though beneath the axis of
large-scale ridging aloft, a substantially moist/unstable
environment persisting near the front should fuel a
continuation/southeastward progression of the ongoing storms through
the day. Several CAM runs suggest a fairly well-organized MCS may
persist through the morning and into the afternoon -- which could be
accompanied by risk for locally damaging winds. Meanwhile, with at
least some of the convection likely to lie to the cool side of the
front, large hail with slightly elevated storms is expected. While
southeastward extent of the possible convective progression remains
uncertain, have expanded the MRGL risk southeastward across the
Alabama/Georgia vicinity where separate/isolated strong to locally
severe storms may develop during the afternoon.
...Portions of West Texas...
Strong heating/destabilization will occur along the dryline across
portions of western Texas Friday, though the airmass should largely
remain capped. Hints persist within model guidance that heating may
permit local breaches of the cap however, resulting in a couple of
isolated, rather high-based storms by late afternoon. Though shear
will remain modest, degree of CAPE suggests robust updrafts, and
attendant risk for hail and/or damaging winds with any storm which
does develop. Storms should diminish into the evening as diurnal
stabilization commences.
...MAXIMUM RISK BY HAZARD...
Tornado: 5% - Slight
Wind: 15% - Slight
Hail: 15% SIG - Slight
..Goss.. 06/20/2019
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1155 AM CDT Thu Jun 20 2019
Valid 201700Z - 211200Z
...Sacramento Valley...
With 15 mph surface winds expected to continue into some portion of
the evening, especially in terrain-favored locations, there is a
possibility that elevated fire weather concerns will last longer
than anticipated before enough boundary layer cooling can raise RH
above 20%.
Further details can be found in the previous discussion.
..Wendt.. 06/20/2019
.PREV DISCUSSION... /ISSUED 0155 AM CDT Thu Jun 20 2019/
...Synopsis...
A mid-level shortwave trough will amplify across the western CONUS
through the period, with a surface low-pressure trough developing
across the Great Basin, and a cold front moving southward across the
central Rockies regions to the southern Great Basin. Behind the cold
front, cool surface temperatures and relatively higher relative
humidity values are expected despite windier conditions. With
surface high pressure building in from off the Pacific Coast, a
modest pressure gradient will become established across portions of
northern California, promoting dry, breezy conditions across parts
of the Sacramento Valley, where some potential will exist for
wildfire spread.
...Northern California...
During the afternoon hours, deep mixing of the boundary layer will
result in downslope flow along the southern extent of the Klamath
Mountains. Winds out of the north at 15-20 mph amidst 15-25% RH are
expected up until sunset, when nocturnal cooling and diminished
boundary layer mixing will temper the wildfire threat. An elevated
area was delineated to account for this scenario.
...Southern Great Basin/Four Corners regions...
Stronger mid-level flow at the base of the trough will overlap a
deeply mixed boundary layer, promoting widespread 20+ mph sustained
west-southwesterly surface winds and RH in the 10-20% range by peak
heating of the afternoon. Currently, fuels are modestly (at best)
receptive to wildfire spread given recent rainfall over the past few
days. As such, no areas were delineated at this time, though
meteorological conditions will support wildfire spread potential
over any isolated patches of fuels that have cured sufficiently
after the most recent rainfall. In addition, the lack of forecast
rainfall and aforementioned dry/windy conditions will prime the
finer fuels across lower elevations for Day 2/Friday.
...Please see www.spc.noaa.gov/fire for graphic product...
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