Storm Prediction Center Forecast


RSS Mesoscale Discussions from Storm Prediction Center

SPC - No watches are valid as of Tue Jun 25 06:19:01 UTC 2019

No watches are valid as of Tue Jun 25 06:19:01 UTC 2019.


SPC - No MDs are in effect as of Tue Jun 25 06:19:01 UTC 2019

No Mesoscale Discussions are in effect as of Tue Jun 25 06:19:01 UTC 2019.


SPC Jun 25, 2019 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
0100 AM CDT Tue Jun 25 2019

Valid 251200Z - 261200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
KANSAS INTO SOUTHEAST NEBRASKA INTO NORTHWEST MISSOURI...

...SUMMARY...
Scattered to isolated severe storms are possible from the upper
Great Lakes region southwestward into the mid Missouri Valley and
central Plains. A few strong to severe storms with gusty winds and
hail are possible over the northern Rockies as well as west Texas. A
few strong storms with gusty winds are also possible from east Texas
into the lower Mississippi Valley region.

...Synopsis...

Shortwave trough currently moving through the Great Lakes will
continue northeast into southeastern Canada this morning. In wake of
this feature, general high rises will occur within belt of modest
westerlies from the central through northern Plains. Weak vorticity
maxima embedded within this zone of flow will play a role in
thunderstorm initiation this afternoon. Surface low associated with
the northern-stream shortwave trough will occlude over Ontario.
Trailing front will extend southwest through MN into southwestern NE
this morning. This front will advance southeast during the day and
likely extend from northeast WI through IA and southern NE where it
will stall near the KS border. A dryline will stretch from west TX
through northwest KS where it will intersect the front.

...Central Plains through the middle Missouri Valley and upper Great
Lakes...

Rich low-level moisture with upper 60s to 70 F dewpoints will advect
northward through the pre-frontal warm sector and into the central
Plains and middle MO Valley region beneath steep mid-level lapse
rates. This will result in a corridor of moderate to strong
instability from KS, southern NE, northern MO into IA (2500-4000
J/kg MLCAPE). A capping inversion resulting from warm air at the
base of an elevated mixed layer will delay surface based
thunderstorm initiation until mid-late afternoon. Model consensus is
that storms should eventually develop from near the dryline/cold
front intersection over northwest KS, eastward along the front
across northern KS into southern NE fostered by frontal convergence
and ascent associated with weak impulses moving through the zonal
flow regime. Given the degree of instability and 30-35 kt effective
bulk shear, some supercell structures are likely, but storms may
eventually congeal into one more clusters. Very large hail, a couple
tornadoes, and damaging wind will be possible through mid evening.

Farther north toward the Great Lakes, storm coverage could be more
sparse due to potential subsidence and weaker frontal convergence in
wake of primary shortwave trough. Nevertheless, at least isolated
storms are possible from WI into lower MI where stronger wind
profiles and 30-35 kt vertical shear will support a threat for
organized structures with damaging wind and large hail the main
threats.

...West Texas...

Isolated to widely scattered storms are expected to develop along
the dryline across west TX by late afternoon. Winds aloft will
continue to decrease resulting in weak shear as heights rise during
the day. However, the thermodynamic environment with steep lapse
rates and moderate instability will support a risk for downburst
winds and hail through early evening.

...Northern Rockies through central High Plains...

At least isolated storms will likely develop over the northern
Rockies and spread east into the high Plains where 45+ kt effective
bulk shear will support potential for some supercell structures.
Moisture will be limited and storms will be high based, but will
pose a risk for downburst winds and large hail. Activity might
consolidate into one or two small clusters overnight. A slight risk
might be needed for a portion of this region in later updates, most
likely from western NE into western SD and northeast WY.

..Dial/Cook.. 06/25/2019

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SPC Jun 25, 2019 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook
      
Day 2 Outlook Image
Day 2 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0116 AM CDT Tue Jun 25 2019

Valid 261200Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
NORTHERN INTO CENTRAL MONTANA WEDNESDAY AFTERNOON AND EVENING...

CORRECTED FOR GEN THUNDER LINE ERROR

...SUMMARY...
Widely scattered severe storms capable of wind and hail are possible
across parts of the central High Plains into the northern Plains,
and over much of Montana on Wednesday. Additional strong storms are
expected from northern Indiana into the lower Great Lakes vicinity.

...Northern Rockies/Montana...

An upper low off the Pacific Northwest coast will shift eastward
only slightly on Wednesday as height rises reinforce the upper ridge
over the Plains. As the upper low slowly pivots inland,
strengthening southwesterly midlevel flow will overspread the Great
Basin and northern Rockies. East/southeasterly low level flow across
the northern Plains will bring mid 40s to mid 50s dewpoints eastward
across much of MT into northern ID and portions of the Columbia
Basin. Strong heating and steep midlevel lapse rates will result in
MLCAPE values from around 500-1500 J/kg. A deeply mixed sub-cloud
layer (i.e. inverted-v thermodynamic profile) and strong midlevel
flow will support strong downdrafts, and strong to severe wind gusts
are possible from northeast OR/southeast WA eastward across much of
MT. Shear profiles indicate high-based supercells are possible, and
elongated hodographs above 3-4 km in the midst of 7.5-8.5 C/km
midlevel lapse rates will support large hail as well, especially
across parts of northern/central MT where a Slight risk has been
included. 

...Northern Plains to Central High Plains Vicinity...

Height rises are expected across the Plains but temperatures aloft
will remain cool, maintaining a large area of very steep lapse rates
atop a moderate EML in the 850-700 mb layer. Some guidance suggests
convection may be ongoing, but decaying, at the beginning of the
period in the vicinity of the mid-MO Valley. This activity could
pose a marginal severe threat, but more likely will result in
various outflow boundaries overlying the region. Southerly low level
flow will maintain rich boundary-layer moisture, with dewpoints in
the 60s to mid 70s F across all but the western portions of the
Plains states where a surface trough and dryline will extend north
to south from far eastern WY/western NE through western KS and into
the OK/TX Panhandles. Mid to upper level west/southwesterly flow
across the central/southern Rockies will be rather modest, but there
is some evidence of a weak impulse ejecting across the region during
the afternoon. Strong heating/instability could lead to isolated
storms during the late afternoon/evening hours if forcing becomes
strong enough to overcome moderate capping. Strong wind gusts and
hail would be possible with any storms that form. 

Some guidance suggests the as a southerly low level jet increases
during the evening/overnight, a complex of storms could emerge from
dryline convection perhaps in NE, or develop along outflow from
aforementioned morning convection. The overall conditional and
uncertain nature of the threat across the region will preclude
higher severe probabilities at this time. 

...Northern Indiana/OH into PA/NY/VT...

A couple of weak impulses associated with northern Ontario mid/upper
low will migrate through westerly flow in the Great Lakes vicinity
on Wednesday afternoon. This will result in a moderate midlevel flow
around 30-40 kt downstream of Lake Michigan toward western PA/NY.
Southwesterly low level flow will maintain 60s dewpoints and strong
heating will result in 1500-2500 J/kg MLCAPE. As a result, one or
more bands of storms are expected to develop and shift
east/southeast across the region. Strong wind gusts will be the main
threat but some near-1 inch hail is possible as well.

...MAXIMUM RISK BY HAZARD...
Tornado:   2%     - Marginal
Wind:     15%     - Slight
Hail:     15%     - Slight

..Leitman.. 06/25/2019

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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
1143 PM CDT Mon Jun 24 2019

Valid 251200Z - 261200Z

...Synopsis...
Fire-weather concerns will be greatest across the West and Southwest
this afternoon and early evening.  A closed low initially over
northeastern Pacific waters west of British Columbia will migrate
southward and impact much of the West through the forecast period as
shortwave ridging aloft develops over the central Rockies.  The net
result of this pattern will be increasing southwesterly flow aloft
atop a dry low-level airmass in the Great Basin and vicinity.  While
this would ordinarily result in a classic synoptic pattern for
western U.S. fire weather, the relatively slow start to the season
(due to a wet spring) will mitigate fire weather concerns in most
areas.

...Northwestern Nevada southward through the Lower Colorado River
Valley and portions of Arizona...
Vertical mixing processes beneath enhanced flow aloft and a
favorably oriented surface trough from Nevada southward through
western Arizona will result in a fairly broad area of critically
strong (20+ mph) surface winds in much of Nevada.  These winds will
be slightly weaker in Arizona.  Meanwhile, the dry airmass over the
region and mixing will lower RH values to critical thresholds -
lowest in the lee of the Sierras and in southern Nevada.  These
conditions will ordinarily result in critical delineations across
western and southern Nevada, though fuels continue to be unfavorable
for large fires except for on a localized basis away from where
surface winds will be strongest.  Thus, elevated fire weather
delineations remain in place to address the fire weather scenario.

..Cook.. 06/25/2019

...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
1145 PM CDT Mon Jun 24 2019

Valid 261200Z - 271200Z

...Synopsis...
Elevated fire weather conditions will continue in the West Thursday.
 A cutoff low west of the WA/OR coast will continue to migrate
slowly southward throughout the forecast period while shortwave
ridging shifts northeastward toward the northern High Plains.  This
will result in increased southwesterly flow across dry areas of the
West - a regime similar to D1/Wednesday though with slightly
increased flow both aloft and at the surface.

...Western Nevada southeastward into southwestern Colorado and
western New Mexico...
Vertical mixing of stronger flow aloft and continued surface
troughing in the Great Basin will promote development of widespread
20+ mph surface winds with a few higher gusts - especially from
northern Arizona northward through the remainder of the Great Basin.
 Meanwhile, critically low RH values will exist during the evening
due to a continued dry airmass.  Fuels are driest and most
supportive of fire spread in areas of southern Arizona - displaced
from stronger flow and low RH to the north of this area.  Again, the
relatively slow start to the fire season will mitigate fire weather
concerns - with only locally critical fire weather conditions
expected where fuels are dry.

..Cook.. 06/25/2019

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

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