SPC Forecast Products
Current Mesoscale Discussions
SPC - No watches are valid as of Tue Dec 5 07:24:02 UTC 2023
No watches are valid as of Tue Dec 5 07:24:02 UTC 2023.
SPC - No MDs are in effect as of Tue Dec 5 07:24:02 UTC 2023
No Mesoscale Discussions are in effect as of Tue Dec 5 07:24:02 UTC 2023.
SPC Dec 5, 2023 0600 UTC Day 1 Convective Outlook
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1116 PM CST Mon Dec 04 2023
Valid 051200Z - 061200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms are not expected across the contiguous United States.
...Discussion...
Large-scale pattern will prove unfavorable for thunderstorms today
across the CONUS. Offshore flow will prevail across most of the
Atlantic/Gulf Coasts and any appreciable buoyancy has been shunted
well south and east of the United States.
Across the western US, warm conveyor will gradually sag south along
the west Coast, but the primary upper trough will hold well
offshore. Weak instability may be noted within the conveyor, but
primarily west of -125 longitude. Even within this corridor,
elevated convection should remain too shallow/weak to warrant any
meaningful risk for lightning.
..Darrow.. 12/05/2023
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SPC Dec 5, 2023 0700 UTC Day 2 Convective Outlook
SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1142 PM CST Mon Dec 04 2023
Valid 061200Z - 071200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Wednesday.
...Discussion...
Thunderstorm potential will remain negligible across much of the
CONUS. Sporadic lightning flashes are possible over a portion of
northern CA to coastal OR, mainly during the late afternoon and
evening on Wednesday.
A shortwave trough over the northeast Pacific will move inland
across northern CA and the Northwest. In the wake of trough passage,
cooler mid-level temperatures amid an expanding plume of steep lapse
rates will overspread much of the Pacific Northwest. As this occurs,
scant surface-based buoyancy should develop along coastal OR into a
portion of northern CA towards late afternoon. 00Z HREF guidance
suggests scattered low-topped convection will become common in this
time frame, with the deepest convection capable of producing
sporadic lightning flashes.
..Grams.. 12/05/2023
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SPC Dec 5, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0121 AM CST Tue Dec 05 2023
Valid 071200Z - 081200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Thursday.
...Discussion...
Thunderstorm potential will be negligible across much of the CONUS
on Thursday. The lone exception will be over the Pacific Northwest,
where sporadic lightning flashes are possible, mainly during the
first half of the period near the coast.
The next in a series of shortwave troughs will impinge on the
Pacific Northwest coast on Thursday, before digging towards the
northern Great Basin by Thursday night. Already steep 700-500 mb
lapse rates in the wake of a trough passage on D2/Wednesday, will
steepen further between 8 to 8.5 C/km as cold 500-mb temperatures
from -30 to -35 C become common. This should compensate for
gradually decreasing boundary-layer moisture with low 40s surface
dew points holding along the coast through Thursday afternoon. Scant
surface-based buoyancy is anticipated with multiple rounds of
scattered low-topped convection. Similar to D2, sporadic lightning
flashes will be possible, although focused somewhat farther north
along the OR/WA coast and mainly in the morning to afternoon.
..Grams.. 12/05/2023
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SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1120 PM CST Mon Dec 04 2023
Valid 051200Z - 061200Z
...NO CRITICAL AREAS...
...Synopsis...
An upper-level ridge will shift eastward over the Divide today. At
the surface, high pressure will strengthen in the Plains as it moves
southeastward with time. Surface high pressure will also remain
within the Great Basin into the Western Slope. Fire weather concerns
throughout the CONUS should remain low given generally unreceptive
fuels and light winds. Some stronger offshore winds are likely in
southern California. These winds will peak this morning before
weakening through the day. Though fuels are not overly receptive and
the lowest RH will not phase well with the strongest winds, locally
elevated conditions would be possible where pockets of dry fuels
exits within the terrain.
..Wendt.. 12/05/2023
...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
NWS Storm Prediction Center Norman OK
1122 PM CST Mon Dec 04 2023
Valid 061200Z - 071200Z
...NO CRITICAL AREAS...
...Synopsis...
The upper-level ridge will continue to shift eastward into the
Missouri/Mississippi Valley regions on Wednesday. A trough will
begin to develop into the West once again, but will be relatively
ill-defined initially. At the surface, a combination of a modestly
intensifying surface high in the Southeast and broad surface low
pressure in the northern Rockies southward into the High Plains will
increase the pressure gradient within parts of the Plains. Gusty
south/southwest winds are possible from the southern High Plains
into the central Plains and parts of the Upper Midwest. Temperatures
should remain rather cool farther north and keep RH elevated. Warmer
temperatures are expected farther south and within areas of stronger
downslope winds. Pockets of locally elevated fire weather are
possible in the southern High Plains and perhaps parts of southeast
Wyoming should sufficiently dry fine fuels exist.
..Wendt.. 12/05/2023
...Please see www.spc.noaa.gov/fire for graphic product...
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