RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Fri Feb 21 22:09:02 UTC 2020.
No Mesoscale Discussions are in effect as of Fri Feb 21 22:09:02 UTC 2020.
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0136 PM CST Fri Feb 21 2020
Valid 212000Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for thunderstorms appears negligible across much of the
nation today into tonight, but a couple of thunderstorms could
develop near southern California coastal areas late tonight.
...20Z Update...
No changes needed. See previous forecast discussion below.
..Mosier.. 02/21/2020
.PREV DISCUSSION... /ISSUED 1026 AM CST Fri Feb 21 2020/
...Synopsis...
Large-scale mid-level troughing will continue to progress across and
east of the Atlantic Seaboard today through tonight. As this
occurs, an associated significant cold front will advance
southeastward through the western Atlantic and the remainder of the
southern Florida Peninsula, while likely stalling and weakening over
the southern Gulf of Mexico.
In the wake of the front, generally dry and/or stable conditions
prevail across much of the nation. Little substantive change is
expected through early Saturday, but models do indicate that a
significant closed low emerging from the southern mid-latitude
eastern Pacific probably will begin progressing inland across
southern California coastal areas by 12Z Saturday.
...Southern Florida Peninsula...
Although the pre-frontal boundary layer is moist and potentially
unstable across southeast coastal areas and the Keys, inhibition
associated with relatively warm and dry air in the lower/mid
troposphere, coupled with weak forcing for ascent, still appears
likely to preclude thunderstorm development before the front
advances offshore.
...Southern California coastal areas...
Model output appears generally similar with the cold core (-24 to
-26 C at 500 mb) of the mid-level closed low spreading into southern
California coastal areas, from around Santa Barbara County into the
Los Angeles Basin, by 09-12Z. Based on latest forecast soundings,
steepening of lower/mid tropospheric lapse rates will result in
increasingly favorable thermodynamic profiles to support potential
for isolated to widely scattered weak thunderstorm development by
the end of the period.
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0141 PM CST Fri Feb 21 2020
Valid 221200Z - 231200Z
...NO CRITICAL AREAS...
Much of the previous forecast remains on track. Relatively dry
conditions (20-30% RH) along with westerly surface winds sustained
up to 15 mph may occur across portions of western Pennsylvania into
parts of the Mid Atlantic. However, cooler temperatures and
marginally receptive fuels will limit wildfire-spread potential to a
degree. Dry conditions will also persevere along the Florida/Georgia
border during the afternoon, though northerly winds are expected to
be relatively light.
..Squitieri.. 02/21/2020
.PREV DISCUSSION... /ISSUED 0141 AM CST Fri Feb 21 2020/
...Synopsis...
Fire-weather conditions will remain generally quiescent Friday.
Light, dry northwesterly flow will develop across western Nebraska
west of a surface trough across central/northeastern parts of the
state. Though RH values could fall to around 15% or so during the
afternoon, model guidance suggests that winds should be too light
for any substantial concerns, however. These dry/breezy conditions
may extend northwestward toward western South Dakota and eastern
Montana breifly during the afternoon, but conditions should fall
below even elevated criteria in most areas.
...Please see www.spc.noaa.gov/fire for graphic product...
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