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LU9DCE > ALERT 06.01.21 17:02z 212 Lines 11874 Bytes #999 (0) @ WW
BID : 1297_LU9DCE
Read: GUEST
Subj: STORM PREDICTION CENTER 06 01
Path: HB9ON<IW8PGT<IZ3LSV<IK5FKA<IK5FKA<LU9HGS<LU3DVN<LU9DCE
Sent: 210106/1700Z 1297@LU9DCE.TOR.BA.ARG.SOAM LinBPQ6.0.21
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ESTACION DE PACKET RADIO - BUENOS AIRES (GF05OM)
BOLETINES INFORMATIVOS PROGRAMADOS (BIP)
LU9DCE@GMX.COM
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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1158
PM CST Tue Jan 05 2021
Valid 061200Z - 071200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE TEXAS COASTAL PLAIN...
...SUMMARY... A few severe storms are possible today into tonight
along the western Gulf Coastline. Primary hazards are expected to
be damaging wind gusts and a couple tornadoes.
...Synopsis... A mid-level trough is expected to become more
negatively tilted as it amplifies and crosses the southern Plains
region. Immediately ahead of the trough, a surface low is also
expected to intensify across central Texas, with a 40+ kt 850 mb
jet advecting a seasonably moist low-level airmass across eastern
Texas. Elevated convection is expected to develop along the nose of
the low-level jet shortly after 12Z and traverses the OK/AR/KS/MO
border area. By early afternoon, as the trough takes on a more
positive tilt, a 55-75 kt westerly mid-level jet is expected to
rapidly overspread the warm sector across eastern TX. Deep forcing
for ascent will encourage new thunderstorm development along and
south of a warm front across east-central TX, and ahead of a cold
front poised to be sweeping across the TX Hill Country. The strong
westerly mid-level flow bisecting the south-southwesterly low-level
jet will promote ample veering with height for organized thunderstorm
updrafts, with a few severe storms likely.
Meanwhile, another trough aloft, with multiple embedded mid-level
impulses, will approach the West Coast. The first impulse is
expected to reach northern California and southwest Oregon by
morning. Despite deep-layer ascent, buoyancy is expected to be on
the more marginal end, but should support a few lightning flashes.
Later in the afternoon, a second impulse will approach the Pacific
northwest, supporting a couple lightning flashes as well.
...TX Coastal Plain... A warm front will slowly drift
northward across east-central Texas through the day, with modest
destabilization expected across the warm sector. Surface temperatures
are expected to peak into the mid 60s to near 70F, with lower
60s F dewpoints advecting northward from the Gulf of Mexico. With
up to 6-7 C/km mid-level lapse rates expected to overspread the
warm sector by mid-afternoon, resulting in up to 800 J/kg MLCAPE
by afternoon peak heating. As the mid-level trough and associated
deep-layer ascent approaches, the development of relatively more
intense convection is expected around the 18-20Z time frame. While
strong forcing along the cold front suggests that a squall line may
develop through the afternoon along the Texas Coastal Plain, ample
veering with height in the lowest 3 km suggests that semi-discrete
supercells are possible, with at least transient low-level rotation
expected. Any supercell structure that can become sustained and
anchor to the warm front may ingest 150-300 m2/s2 effective SRH,
with a couple tornadoes possible. Given the aforementioned strong
flow fields aloft, adequate downward momentum transport within the
squall may foster multiple instances of damaging winds. A Slight
risk has been introduced to account for the wind/tornado threat.
Towards the end of the period (roughly 07-12Z), modest buoyancy may
advect inland along portions of the southeast LA/MS coastline,
where deep-layer and low-level shear would support storm
organization/rotation. Any storms that can manage to root in the
boundary layer and become surface based may also pose a risk of a
couple damaging gusts and perhaps a tornado.
..Squitieri/Darrow.. 01/06/2021
SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1156
PM CST Tue Jan 05 2021
Valid 071200Z - 081200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER FAR SOUTHERN
MISSISSIPPI AND ALABAMA...AND THE FLORIDA PANHANDLE...
...SUMMARY... Thunderstorms are possible Thursday across the
Southeast, with a conditional threat of isolated severe storms from
the Mississippi and Alabama coasts into the Florida Panhandle.
...Synopsis... A strong shortwave trough with cyclonically
curved jet max will move east across the southeastern states
on Thursday, with upper low moving from northern LA toward the
southern Appalachians by Friday morning. Of particular note will
be the cold temperatures aloft, with -20 C at 500 mb as far south
as Mobile AL. Strong westerly winds aloft will lengthen hodographs
across the region, particularly the northern Gulf Coast.
At the surface, a low is forecast to move east across southern parts
of MS, AL, and GA, and perhaps across the FL Panhandle as well.
Large-scale lift with this system will conditionally favor a
few strong storms, but boundary-layer details will determine how
productive of an event it is.
Elsewhere, cooling temperatures aloft with an upper trough will
impact the Pacific Northwest, with instability developing overnight
favoring a few lightning flashes.
...MS/AL/FL Panhandle... A relatively cool and stable surface
air mass will be in place over much of the Southeast during the
day ahead of the surface low. However, southerly winds ahead of
the low will bring at least mid 50s F dewpoints onshore across
far southern MS, AL, and the FL Panhandle, possibly resulting in
sufficient SBCAPE. Forecast soundings indicate up to 500 J/kg SBCAPE
may develop immediately ahead of the cold front and dry slot aloft,
where cooling aloft will be rapid. Large values of SRH will be
present due to the warm advection atop the cool boundary layer,
and will be reduced rapidly as the front approaches. There may
be a brief window of opportunity where SBCAPE favor wind gusts
or a tornado, and effective SRH remains strong. If this happens,
isolated supercells may form. This event is highly conditional on
the surface air mass and moisture return. If the air mass remains too
cool along the coast, then little if any severe threat may develop.
...Coastal OR and northern CA... Increasing moisture may result
in elevated CAPE across the region late in the day, with sporadic
thunder possible. However, the strongest cooling aloft will occur
close to 12Z Friday along the coast, and this is when models indicate
non-zero SBCAPE may develop. Forecast soundings from various models
are not in very good agreement regarding instability, but this area
will need to be watched in subsequent outlooks. Shear will remain
strong, and may conditionally favor a strong storm along the coast
should instability be greater than currently forecast.
..Jewell.. 01/06/2021
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1224
AM CST Wed Jan 06 2021
Valid 081200Z - 091200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY... There is little chance of thunderstorms over the
continental United States on Friday.
...Synopsis... A shortwave trough will be situated over the
Southeast Friday morning, with a surface low off the SC coast. A
cold front will trail southwest over south FL early in the day,
but rapid drying will occur from the west, and thunderstorms are
not expected. High pressure will stretch from the Plains into the
Gulf of Mexico, maintaining stable conditions.
To the west, a shortwave trough will be near the coastal Pacific
Northwest early in the day, but will move east during the afternoon
with height rises along the coast. While minimal elevated CAPE may
be present early, the trend is expected to be toward little to no
thunderstorms throughout the day.
..Jewell.. 01/06/2021
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK
0154 AM CST Wed Jan 06 2021
Valid 091200Z - 141200Z
...DISCUSSION... In the wake of an upper trough departing the
Mid Atlantic, another shortwave trough will dive southward across
the Four Corners on Saturday/D4, and into TX on Sunday/D5. A large
surface ridge will be in place during this period, with pressure
centers over the Great Basin and Northern Plains. Given the low
latitude of this shortwave trough, low pressure is forecast to form
over the western Gulf of Mexico on Sunday/D5. Low-level moisture
return will be minimal over land due to poor trajectories around the
surface ridge, but low 60s F dewpoints are possible near Brownsville
TX before a cold front surges east. Only minimal elevated instability
is forecast over southern TX.
From Monday/D6 through Wednesday/D8, little thunderstorm activity
is anticipated. As the aforementioned shortwave trough continues
across the Gulf of Mexico, another wave is forecast to move into
the central Plains or Great Lakes, depending on the model. In either
case, reinforcing surface highs are expected, minimizing potential
for destabilization.
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK
0103 AM CST Wed Jan 06 2021
Valid 061200Z - 071200Z
...NO CRITICAL AREAS...
...Synopsis... A mid-level trough will deepen as it progresses
across the Southern Plains today, with a surface cyclone expected
to move across eastern Texas along with a cold front. Breezy,
modestly dry conditions are expected to accompany the post cold
frontal environment this afternoon across portions of the southern
High Plains. While locally Elevated conditions may occur along
the New Mexico/Texas border, the brevity of the more favorable
wind/RH overlap precludes fire weather highlights. Meanwhile,
high pressure will build across the Inter-mountain West, with a
pressure gradient and associated dry offshore flow expected across
portions of southern California. However, given recent precipitation
accumulations and the localized nature of the dry/breezy conditions
across the southern Transverse Ranges, fire weather highlights
were also withheld across this area. Lastly, a dry surface airmass
(i.e. 30-45% RH) is expected across parts of the Florida Peninsula
during the afternoon hours, but with light and variable surface
winds, hence no fire weather delineations.
..Squitieri.. 01/06/2021
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK
0127 AM CST Wed Jan 06 2021
Valid 071200Z - 081200Z
...NO CRITICAL AREAS...
...Synopsis... As a mid-level trough and associated surface cyclone
progress across the southeast U.S, another trough will impinge on the
West Coast while a separate mid-level impulse ejects into the Plains
states Day 2/Thursday. Precipitation accumulations with the cyclone
across the Southeast, along with cooler temperatures associated with
high pressure across the western U.S, will serve to limit significant
wildfire-spread concerns. Locally Elevated conditions may accompany
the post cold frontal environment across the South TX Brush Country,
as well as with continued dry offshore flow in terrain favoring areas
of the southern Transverse Ranges in south California. However,
the brief and sparse nature of the more favorable surface wind/RH
overlap in both areas precludes Elevated highlights at this time.
..Squitieri.. 01/06/2021
...Please see www.spc.noaa.gov/fire for graphic product...
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* This is complicated. Has to do with interrupts. Thus, I am *
scared witless. Therefore I refuse to write this function. :-P
-- From the maclinux patch
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