SPC - No watches are valid as of Mon Aug 3 08:38:02 UTC 2020

No watches are valid as of Mon Aug  3 08:38:02 UTC 2020.

No Mesoscale Discussions are in effect as of Mon Aug 3 08:38:02 UTC 2020.

SPC Aug 3, 2020 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1215 AM CDT Mon Aug 03 2020

Valid 031200Z - 041200Z


A few tornadoes in association with Isaias appear possible across
the eastern Carolinas later tonight. A few strong storms are also
possible across parts of the Appalachians and Mid-Atlantic and over
the Rockies region.


Tropical Storm Isaias remains on track to move inland along the
Carolina Coast Monday evening. Low-level shear is forecast to
increase markedly after sunset, east of the land-falling center,
where 850mb flow may be in excess of 70kt. Shear profiles will
become increasingly favorable for supercells, and a few tornadoes,
across coastal Carolina during the latter half of the period.
Reference https://nhc.noaa.gov for more information on Tropical
Storm Isaias

Farther inland, modest southwesterly flow will persist across the
Appalachians into the Mid-Atlantic in advance of primary trough
located over the MS Valley. While deep-layer flow will be supportive
of organized updrafts, poor lapse rates should limit updraft
strength. Even so, an isolated damaging wind gust can not be ruled
out with diurnally driven convection.


Strong short-wave trough will eject inland across the northern
Rockies into western MT during the afternoon hours. This feature
will flatten the western US ridge such that scattered convection is
expected to develop along/ahead of a frontal zone as it progresses
into central MT. Models suggest strong boundary-layer heating will
allow surface temperatures to warm into the upper 80s/lower 90s over
southern MT and this should be more than adequate for breaching
convective temperatures by 22z. As a result, high-based
thunderstorms should develop within a favorable large-scale pattern
for sustained updrafts capable of producing isolated damaging wind
gusts/hail. Modest north-northwesterly flow from eastern WY into
eastern NM will also allow diurnally driven convection some
opportunity to briefly organize with some threat for gusty
winds/marginally severe hail.

..Darrow/Wendt.. 08/03/2020

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SPC Aug 3, 2020 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
0104 AM CDT Mon Aug 03 2020

Valid 041200Z - 051200Z


Some tornado threat will be possible from eastern North Carolina
into southern New England Tuesday into Tuesday night, in association
with Isaias. A few severe thunderstorms will also be possible across
portions of the northern and central High Plains.

...Eastern NC into Southern New England...

T.C Isaias is forecast to be centered over northeastern NC Tuesday
morning. Forecast soundings continue to show low level shear
increasing through the morning and into the afternoon from the
Mid-Atlantic into southern New England, as the system tracks
northeast with increasing forward speed through Wednesday morning.
Low level shear will be favorable for rotation in cells developing
over the Coastal Plain or moving inland in outer bands as low level
hodographs become enlarged with northeast extent through peak
heating. A couple of tornadoes will be possible with this activity,
and an upgrade to Slight risk may be needed in subsequent outlooks
as confidence in timing and track increases.

...Northern/Central High Plains...

A weak shortwave impulse will migrate through northwesterly flow
aloft during the afternoon/evening. Upslope southeasterly low level
flow will transport mid 50s to near 60 F dewpoints westward across
eastern CO into western NE/KS where strong heating will aid in
moderate destabilization amid steep midlevel lapse rates. Forecast
soundings indicate effective shear greater than 35 kt, resulting in
organized, rotating updrafts. Meanwhile, inverted-v sub-cloud
thermodynamic profiles indicate potential for strong downbursts. As
storms move off of higher terrain near the I-25 corridor, a few
severe storms capable of strong gusts and large hail are expected
during the late afternoon and evening hours. Inhibition will
increase with eastward extent, and convection is expected to
gradually weaken as it tracks east/southeast toward the OK/TX
Panhandle and western KS by late evening/overnight.

..Leitman.. 08/03/2020

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SPC Aug 3, 2020 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook
Day 3 Outlook Image
Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0230 AM CDT Mon Aug 03 2020

Valid 051200Z - 061200Z


A few strong storms capable of gusty winds and hail are possible
Wednesday afternoon and evening over portions of the central High

...Central High Plains...

Conditions on Wednesday will be similar to those on Tuesday.
However, forecast guidance does indicate some stronger capping may
be in place. Otherwise, northwesterly mid/upper level flow will
persist as an upper trough shifts eastward over the Rockies and
adjacent High Plains. Thunderstorms are expected to develop in moist
upslope flow during the afternoon and shift east/southeast across
eastern CO into portions of western NE and perhaps western KS.
Forecast soundings indicate shear profiles capable of supporting
organized, rotating updrafts amid weak to moderate instability and
steep midlevel lapse rates. This should once again result in a few
strong to perhaps severe storms capable of gusty winds and hail
during the late afternoon and evening. Convection should again
weaken during the late evening/overnight hours.

...Northern New England...

The remains of Isaias are forecast to be located over
central/northern ME Wednesday morning. Forecast soundings suggest
little in the way of tornado potential at this time. The system
should lift quickly northeast during the first few hours of the
period toward the Canadian Maritimes. Trends will be monitored, but
severe potential appears low at this time.

..Leitman.. 08/03/2020

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SPC Aug 3, 2020 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook
Day 4-8 Outlook Image
Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0334 AM CDT Mon Aug 03 2020

Valid 061200Z - 111200Z

A typical summertime pattern will persist over the CONUS during the
Day 4-8 period. An upper anticyclone will generally be centered over
the south-central U.S. Beneath this upper ridge, seasonally
warm/most conditions will extend from the Great Plains into the
Midwest and Southeast. Further west, a series of shortwave troughs
are forecast to migrate across portions of the western states during
the forecast period. Model guidance differs quite a bit with regards
to the strength and track of these features. Nevertheless, these
upper troughs bear watching as they could become drivers of strong
to severe convection from the northern Plains into the Upper Midwest
from Day 5/Fri into Day 7/Sun. Confidence is too low at this time,
given aforementioned uncertainties, to introduce 15% or greater
severe probabilities, but this could change in subsequent outlooks.

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SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook Image
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1236 AM CDT Mon Aug 03 2020

Valid 031200Z - 041200Z

An upper-level trough will move into the northern Rockies today.
Modest to moderate mid-level flow will extend from the
central/northern Great Basin into Idaho. At the surface, a cold
front will progress eastward into the northern Rockies with pendant
surface trough extending through western Utah into southern Nevada.
As mid/high level clouds clear, boundary-layer mixing and an
enhanced surface pressure gradient near the front will promote 15-20
mph with localized higher speeds. RH is expected to fall to 15-20%.
Elevated conditions are also possible within southwest Wyoming and
adjacent portions of the Wasatch and Uintas. Similar wind and RH
combinations can be expected. There is some possibility that
mid/high clouds will linger longer into the afternoon. This could
reduce fire risk in some locations. Locally elevated conditions are
possible near the surface trough into southern Utah, though weaker
mid-level winds should keep the duration and spatial extent low.
Potential for dry thunderstorms in northwestern Colorado and
adjacent southern Wyoming still appears too low to introduce

..Wendt.. 08/03/2020

...Please see www.spc.noaa.gov/fire for graphic product...

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SPC Day 2 Fire Weather Outlook

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook Image
Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0206 AM CDT Mon Aug 03 2020

Valid 041200Z - 051200Z

As a shortwave trough passes into the northern Plains, another weak
shortwave trough will approach the central California coast on
D2/Tuesday. A frontal boundary will remain in place across southern
Idaho into central Wyoming. Strong surface heating will again take
place within the Great Basin.

With similar mid-level winds to Monday, dry/breezy conditions are
possible across southwestern Wyoming. Winds of 15-20 mph will
coincide with 10-20% RH during the afternoon. The overall fire
threat will be limited by sparse fuels. Furthermore, some guidance
suggests that thunderstorms may occur within the Uintas and limit
the duration of elevated conditions. Even so, this would bring some
concern for lightning ignitions should this occur.

Within southern Nevada, mid-level flow will remain modest even with
the approach to of the trough to the west. Strong surface heating
may help increase winds to 15 mph with RH falling to 5-15%. These
conditions will be fairly typical for this area. Fuels are somewhat
drier for this time of year given the lack of monsoon impacts thus

..Wendt.. 08/03/2020

...Please see www.spc.noaa.gov/fire for graphic product...

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