SPC - No watches are valid as of Mon Jul 16 08:53:01 UTC 2018

No watches are valid as of Mon Jul 16 08:53:01 UTC 2018.


No Mesoscale Discussions are in effect as of Mon Jul 16 08:53:01 UTC 2018.

SPC Jul 16, 2018 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
1258 AM CDT Mon Jul 16 2018

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WYOMING INTO THE CENTRAL/NORTHERN HIGH PLAINS AREA...

...SUMMARY...
Locally severe storms are expected this afternoon and tonight from
portions of the Intermountain West into the central/northern High
Plains area, where potential for damaging winds and possibly hail
will exist.  A marginal threat for locally damaging winds is also
apparent across portions of the Great Lakes area.

...Synopsis...
Modest flow aloft will continue to prevail over the southern half of
the U.S., where upper ridging will persist.  Meanwhile farther
north, a short-wave trough crossing the Intermountain West and a
second/larger trough expanding across eastern Canada and the
northeast quarter of the U.S. will allow modestly stronger westerly
flow to evolve across portions of the northern half of the country.

At the surface, a cold front is forecast to move slowly east across
the Great Lakes region, while sagging southeastward across the
Midwest/Ohio valley and southward across the Ozarks and Oklahoma
through the daylight hours.  By Tuesday morning, the front should
extend in an arc from central Quebec southwest across the Lower
Great Lakes and Upper Ohio Valley into the Mid South, westward
across Arkansas and Oklahoma, and then northwestward across the High
Plains.

...Parts of the Idaho vicinity eastward across Wyoming into western
Nebraska and surrounding areas...
As a mid-level short-wave trough moves gradually eastward out of the
northwestern U.S. into the Idaho/Wyoming vicinity, modest mid-level
cooling atop a diurnally warming boundary layer will result in
moderate afternoon destabilization.  Instability will become most
pronounced across central/eastern Wyoming and into the High Plains,
where a more moist boundary layer is anticipated in the vicinity of
the northwest-to-southeast frontal zone.  

Storm development is expected during the afternoon aided by
increasing large-scale ascent, with a few stronger cells possibly
evolving as far west as the southern Idaho/northwest Nevada region,
but likely more numerous farther east into Wyoming.  With
enhanced/30-40 kt mid-level westerlies spreading across the area
atop a low-level easterly component, shear sufficient for
organized/possibly rotating storms should evolve.  As such,
potential for locally damaging winds and possibly hail will likely
accompany stronger cells.

As a southerly low-level jet evolves over the High Plains during the
evening, most CAM output suggests varying degrees of
congealing/upscale growth of convection, possibly resulting in an
MCS shifting east-southeast out of eastern Wyoming into the
southwest South Dakota/western Nebraska and possibly northeast
Colorado area through the evening and into the overnight hours. 
Presuming this evolution manifests, potential for damaging winds may
extend into the overnight hours.

...The eastern Upper Great Lakes and Lower Great Lakes area...
Modest destabilization ahead of the slowly advancing cold front will
support considerable shower/thunderstorm development across parts of
the eastern Upper Great Lakes/Midwest region during the afternoon. 
Though stronger mid-level cyclonic flow will remain farther north
across Ontario and Quebec, 25 to 30 kt mid-level westerlies should
overspread the warm sector north of the Ohio River Valley,
supporting potential for locally stronger/organized storms.  With
both CAPE and shear expected to remain sub-optimal for a more
widespread severe risk, will maintain only MRGL/5% severe
probability across areas in the vicinity of the Great Lakes, mainly
for gusty/locally damaging wind potential.  Storms -- and limited
wind potential -- will spread eastward with time in conjunction with
the slow frontal advance, affecting portions of Pennsylvania and New
York through the evening and possibly into the overnight hours.

..Goss/Squitieri.. 07/16/2018

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SPC Jul 16, 2018 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
0110 AM CDT Mon Jul 16 2018

Valid 171200Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEAST AND CENTRAL TO NORTHERN PLAINS...

...SUMMARY...
A marginal risk for severe storms will be possible on Tuesday in
parts of the Northeast and in the central to northern Plains.

...Northeast...
An upper-level trough will move eastward across the Lower Great
Lakes Region on Tuesday as a cold front advances southeastward
across the Northeast. Surface dewpoints ahead of the front should be
in the upper 60s and lower 70s F. In spite of extensive cloud cover,
some instability should develop ahead of the front from the
Mid-Atlantic northeastward into New England. In addition, forecast
soundings from eastern Pennsylvania into western New England on
Tuesday show 0-6 km shear in the 25 to 35 kt range suggesting enough
shear will be in place for a marginal severe threat. Although
numerous thunderstorms will be ongoing across the region, a few of
the multicell storms that develop ahead of areas that sufficiently
destabilize, could be associated with strong wind gusts.

...Central and Northern Plains...
A shortwave trough is forecast to move southeastward across the
central High Plains on Tuesday. Ahead of this feature, a corridor of
maximized low-level moisture is forecast from the central Plains
northwestward into the northern High Plains where pockets of
moderate instability appear likely to develop by Tuesday afternoon.
Although the distribution of instability remains highly uncertain,
forecast soundings suggest that moderate deep-layer shear will be in
place across most of the moist sector. For this reason,
thunderstorms that develop in the higher terrain and along residual
outflow boundaries in the lower elevations could obtain a marginal
severe threat. Strong wind gusts and hail are forecast to be the
primary threats.

...MAXIMUM RISK BY HAZARD...
Tornado:   2%     - Marginal
Wind:      5%     - Marginal
Hail:      5%     - Marginal

..Broyles.. 07/16/2018

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SPC Jul 16, 2018 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
0159 AM CDT Mon Jul 16 2018

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS INTO THE MID MISSOURI VALLEY...

...SUMMARY...
A marginal severe threat will be possible on Wednesday in parts of
the central and northern Plains into the mid Missouri Valley.

...Central and Northern Plains/Mid Missouri Valley...
A shortwave trough is forecast to move through the central and
northern Plains on Wednesday. At the surface, a moist airmass should
be in place across the central and northern Plains where surface
dewpoints are forecast to be in the lower to mid 60s F. In response
to surface heating, a corridor of moderate instability appears
likely to develop across parts of the region Wednesday afternoon.
The models including the ECMWF, NAM and GFS are not in agreement
concerning where the greatest instability will develop. The ECMWF
model was the compromise solution with a gradient of moderate
instability located from northwest Missouri into southern South
Dakota which seems to be the most favorable scenario. Under this
setup, thunderstorms would develop in southern South Dakota and move
southeastward across eastern Nebraska and western Iowa during the
late afternoon and early evening. Marginally severe wind and hail
would be the primary threats.

..Broyles.. 07/16/2018

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SPC Jul 16, 2018 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
0346 AM CDT Mon Jul 16 2018

Valid 191200Z - 241200Z

...DISCUSSION...
...Thursday/Day 4 and Friday/Day 5...
The medium-range models move a shortwave trough into the upper
Mississippi Valley on Thursday but agreement is not good even early
in the day 4 to 8 period. The ECMWF and GFS are faster than the
Canadian and UKMET solutions while the Parallel-FV3 is deeper and
further south. The ECMWF and GFS solutions suggests the upper-level
trough will not be phased-well with the area of greatest instability
in the central Plains. In spite of this, isolated severe storms
could still form behind the upper-level trough in the mid Missouri
Valley but uncertainty is high due to model spread.

On Friday, the models move the upper-level trough into the western
Great Lakes and mid Mississippi Valley with moderate instability
located in the base of the trough. Moderate deep-layer shear is also
forecast in the mid Mississippi Valley where a severe threat will be
possible late Friday afternoon into the evening. However,
uncertainty concerning the timing of the upper-level trough is
considerable.

...Saturday/Day 6 to Monday/Day 8...
From Saturday to Monday, the models move the upper-level trough
slowly eastward across the eastern U.S. Although moderate
instability may develop each day across parts of the Southeast and
along parts of the Atlantic Seaboard, deep-layer shear is forecast
to be relatively weak. This would keep any severe threat marginal.
Uncertainty concerning the trough timing reduces predictability for
next weekend's forecast.

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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
0116 AM CDT Mon Jul 16 2018

Valid 161200Z - 171200Z

...Synopsis...
A mid-level shortwave trough will be moving over northern
California/southern Oregon and progressing eastward across the
northwestern Great Basin today. The northwestern periphery of
monsoonal mid-level moisture will also glance the Oregon/Idaho
region.

...Central/eastern Oregon, southern Idaho, northeast Nevada, far
northwest Utah...
Modest deep layer ascent will accompany the aforementioned shortwave
trough across the Pacific Northwest. With the addition of diurnal
heating, adequate buoyancy and deep-layer ascent should foster an
environment capable of supporting isolated to scattered
thunderstorms. Precipitable water values of 0.5-0.75 inches will be
common, along with a dry sub-cloud layer. While storm motions will
be rather slow, the dry sub-cloud layers will promote ample
evaporative cooling and localized gusty surface winds. While some
wetting storms are anticipated, potential exists for dry lightning
to occur. Fuels are receptive in the region and fire spread may be
enhanced by any region that can experience dry lightning with gusty
thunderstorm outflows. An isolated dry thunderstorm area was
delineated for regions where confidence is highest for dry strikes.

..Squitieri.. 07/16/2018

...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
0202 AM CDT Mon Jul 16 2018

Valid 171200Z - 181200Z

...Synopsis...
Zonal flow will persist across the Pacific Northwest during the Day
2/Tuesday period. At the surface, a thermal low will develop east of
the Cascades. Mid-level moisture attributed to the monsoon will also
hover over the Great Basin into the Pacific Northwest.

...Central/eastern Washington and Oregon...
A very hot surface airmass is expected to develop east of the
Cascades during the afternoon on Day 2/Tuesday, promoting the
development of a thermal low/trough. A weak pressure gradient will
result from the trough, inducing downslope flow to the lee of the
Cascades. Surface winds are expected to reach up to 15-20 mph during
the late afternoon in the presence of 100 F temperatures and 10-15%
RH. With receptive fuels present, an elevated delineation was made
where windy and hot/dry conditions may support an environment
favorable for fire spread. 

...Idaho/Montana border into far west Wyoming...
Isolated thunderstorms are expected to develop along the periphery
of greater mid-level moisture associated with the monsoon. An
isolated dry thunderstorm delineation was added where the greatest
confidence in dry strikes would be, in addition to faster storm
motions due to a belt of stronger mid-level flow embedded within the
larger scale zonal pattern. Fuels have also become at least
marginally receptive to fire spread.

..Squitieri.. 07/16/2018

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

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