RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Thu Oct 1 06:02:01 UTC 2020.
No Mesoscale Discussions are in effect as of Thu Oct 1 06:02:01 UTC 2020.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1229 AM CDT Thu Oct 01 2020
Valid 011200Z - 021200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today.
...Discussion...
A highly amplified flow field aloft -- featuring a western U.S.
ridge and eastern U.S. trough -- will persist across the country
today and tonight. As a short-wave trough embedded in the
longer-wavelength cyclonic flow west of the trough axis digs
southeastward across the Ohio Valley/Mid South, a
secondary/reinforcing surface cold front is forecast to advance
slowly southward across the Gulf Coast states and eastward across
the East Coast states with time.
With a generally cool/dry/stable airmass to prevail across most of
the country, thunderstorm activity will be limited to the Great
Lakes region, and south Florida.
Across the Great Lakes area and vicinity, steep low- to mid-level
lapse rates will result in modest low-topped instability --
especially near the lakes themselves. This will permit bands of
showers to persist across the area, along with occasional lightning
-- especially during peak heating hours.
Over south Florida, a moist/tropical airmass residing in the
vicinity of the initial/stalled cold front will support isolated
thunderstorm activity -- particularly during the afternoon with the
assistance of sea-breeze enhancement.
..Goss/Bentley.. 10/01/2020
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Thu Oct 01 2020
Valid 021200Z - 031200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Friday.
...Synopsis...
Expansive and deep upper troughing will cover the central and
eastern CONUS early Friday. An embedded shortwave trough is forecast
to quickly progress northeastward through the Northeast States while
a second shortwave drops southeastward through the northern High
Plains/northern Plains and central Plains, reaching the mid MS
Valley by early Saturday morning. At the surface, lee troughing
across the High Plains is anticipated ahead of the approaching
shortwave, with surface cyclogenesis eventually occurring over the
central High Plains. Resulting surface low will move southward into
the TX Panhandle, along the leading edge of southward surging cold
front associated with Plains shortwave trough.
The dry and stable continental air mass in place will preclude
thunderstorm development with either one of the shortwaves mentioned
above. Isolated thunderstorms are possible across south FL, where
modest low-level moisture may contribute to isolated thunderstorms
ahead of slow-moving front, and over the Lower Great Lakes where
cold temperatures aloft could result a flash or two.
Coverage over the Lower Great Lakes is currently expected to be less
than 10%.
Upper ridging over the western CONUS may dampen somewhat as a
compact shortwave trough moves through its northwestern periphery.
Even so, stable conditions will preclude thunderstorm development.
..Mosier.. 10/01/2020
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1157 PM CDT Wed Sep 30 2020
Valid 011200Z - 021200Z
...Synopsis...
An upper level ridge centered over the West Coast will remain mostly
stationary through the day today. This will lead to very little
change in the overall pattern in the western CONUS with continued
offshore flow across southern California. This will lead to elevated
15 to 20 mph winds with some gusts to 25 mph. Winds will be
strongest this morning, but are expected to persist through the day
and possibly strengthen again late tonight and early Friday morning.
Relative humidity will remain very dry (around 5%) in much of this
area through the day.
A reinforcing area of high pressure is currently moving into
northern Montana and will move southward into the Plains today. This
will lead to a tightening surface pressure gradient across portions
of the Plains and gusty winds. A combination of gusty winds and low
relative humidity may occur in western Oklahoma and southern Kansas,
but elevated conditions are not expected to persist long enough to
warrant an elevated delineation at this time.
..Bentley.. 10/01/2020
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1157 PM CDT Wed Sep 30 2020
Valid 021200Z - 031200Z
...Synopsis...
Offshore flow is expected to be ongoing at the beginning of the
period across southern California. Winds will likely weaken through
the day as the pressure gradient relaxes. The winds may fall below
15 mph and bring an end to elevated conditions in this area by mid
day Friday.
Farther east, a mid-level shortwave trough will move from Montana
into eastern Wyoming through the day. Strong mid-level flow
associated with this passing trough will overspread the region and
some gusty winds are expected during the afternoon hours. Winds of
20 to 25 mph are expected with relative humidity ranging from 20 to
30 percent, mostly in eastern Wyoming.
..Bentley.. 10/01/2020
...Please see www.spc.noaa.gov/fire for graphic product...
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