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weather 2024.16

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weather 2024.16

(date: 2024-04-21 09:39:33)


SPC Apr 21, 2024 1630 UTC Day 1 Convective Outlook

date: 2024-04-21, from: NOAA tornado/severe thunderstorm watches, mesoscale discussions, convective outlooks, fire weather outlooks


Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1124 AM CDT Sun Apr 21 2024

Valid 211630Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTH
FLORIDA AND SOUTH GEORGIA...

...SUMMARY...
Isolated damaging gusts and marginally severe hail will be possible
for a few hours this afternoon/evening across south Georgia and
north Florida.

...North FL/south GA this afternoon/evening...
Visible satellite imagery late this morning shows a cumulus field
and a destabilizing airmass to the east of an ongoing band of
convection near a southwest-northeast oriented front.  Ample heating
over the area to the east of patchy cirrus will promote temperatures
warming into the lower 80s deg F.  12z model guidance so far has a
negative bias on surface dewpoints across north FL compared to
observations (3-6 deg F too dry).  This is partially explained by a
richer moist profile observed through almost 850 mb via the 12z
Tallahassee raob.  As a result, slightly higher dewpoints (upper 60s
deg F) and greater buoyancy (1000-1500 J/kg MLCAPE) are expected
than previously forecast.  Water-vapor imagery shows a lead
disturbance moving east across the central Gulf Coast, and it will
reach the northeast Gulf by late this afternoon/early evening. 
Ascent and some strengthening in flow will aid in some storm
organization (reference 50-kt 2-6 km flow at Tallahassee on the 88D
VAD).  Limited low-level convergence and a warm layer near 800 mb
may act to hinder an otherwise more organized potential severe
setup.  Regardless, isolated 50-65 mph gusts and marginally severe
hail are possible with the stronger storms this afternoon into the
early evening.

..Smith/Jewell.. 04/21/2024

Read more

https://www.spc.noaa.gov/products/outlook/day1otlk_1630.html


SPC - No watches are valid as of Sun Apr 21 16:29:02 UTC 2024

date: 2024-04-21, from: NOAA tornado/severe thunderstorm watches, mesoscale discussions, convective outlooks, fire weather outlooks

No watches are valid as of Sun Apr 21 16:29:02 UTC 2024.

https://www.spc.noaa.gov/products/watch/


SPC - No MDs are in effect as of Sun Apr 21 16:29:02 UTC 2024

date: 2024-04-21, from: NOAA tornado/severe thunderstorm watches, mesoscale discussions, convective outlooks, fire weather outlooks

No Mesoscale Discussions are in effect as of Sun Apr 21 16:29:02 UTC 2024.

https://www.spc.noaa.gov/products/md/


SPC Day 1 Fire Weather Outlook

date: 2024-04-21, from: NOAA tornado/severe thunderstorm watches, mesoscale discussions, convective outlooks, fire weather outlooks


Day 1 Fire Weather Outlook Image
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1107 AM CDT Sun Apr 21 2024

Valid 211700Z - 221200Z

...NO CRITICAL AREAS...

The previous forecast (see below) remains on track, with no changes
or additions made.

..Squitieri.. 04/21/2024

.PREV DISCUSSION... /ISSUED 0154 AM CDT Sun Apr 21 2024/

...Synopsis...
A midlevel westerly jet streak will cross the northern Rockies
during the afternoon, while a related cold front overspreads the
region. Strong post-frontal winds are expected across northern MT,
which could briefly overlap 20-30 percent RH. Dry/breezy pre-frontal
conditions are also possible over eastern MT into the western
Dakotas. While locally elevated conditions are possible for both
areas, marginal fuels and a limited overlap of the strongest winds
and lowest RH cast uncertainty on the large-fire threat.

Farther east, breezy/gusty west-northwesterly winds and 25-35
percent RH are possible from MN to Lower MI -- along the southern
periphery of strong northwesterly flow aloft. This could yield
locally elevated conditions, though these conditions appear too
marginal for highlights, given the current state of fuels.

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

Read more

https://www.spc.noaa.gov/products/fire_wx/fwdy1.html


SPC Apr 21, 2024 1300 UTC Day 1 Convective Outlook

date: 2024-04-21, from: NOAA tornado/severe thunderstorm watches, mesoscale discussions, convective outlooks, fire weather outlooks


Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0745 AM CDT Sun Apr 21 2024

Valid 211300Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING ACROSS NORTH FL/SOUTH GA...

...SUMMARY...
Isolated damaging winds near 60 mph and large hail near 1 inch
diameter will be possible for a few hours this afternoon/evening
across south Georgia and north Florida.

...North FL/south GA this afternoon/evening...
A low amplitude shortwave trough over the north central Gulf coast
will progress eastward over south GA/north FL by late afternoon, in
advance of an upstream trough over the mid MS Valley.  An associated
cold front will move slowly southeastward and offshore of the
Carolinas this afternoon, and into central FL by Monday morning. 
Regional 12z soundings from JAX/TLH show lingering steep midlevel
lapse rates and an associated cap which is expected to weaken from
the west by afternoon, when thunderstorm development will become
more probable with surface heating, ascent along the front, and with
larger-scale ascent related to the approaching midlevel trough.  The
warm sector ahead of the front across south GA/north FL will be
characterized by mid 60s dewpoints and surface temperatures ranging
from the mid 70s to lower 80s in cloud breaks by afternoon, where
MLCAPE could approach 1000 J/kg.  Coincident with diurnal
destabilization, midlevel flow will increase to 50 kt with largely
straight hodographs and effective bulk shear of 35-40 kt.  This
environment of moderate buoyancy and vertical shear will support the
potential for multicell clusters and/or low-end supercells capable
of producing isolated damaging gusts near 60 mph and large hail near
1 inch in diameter for a few hours this afternoon/evening.

..Thompson/Kerr.. 04/21/2024

Read more

https://www.spc.noaa.gov/products/outlook/day1otlk_1300.html