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LU9DCE > ALERT 03.12.20 16:04z 193 Lines 10636 Bytes #999 (0) @ WW
BID : 42296_LU9DCE
Read: GUEST
Subj: STORM PREDICTION CENTER 03 12
Path: HB9ON<IW8PGT<IZ3LSV<DB0ERF<DB0RES<ON0AR<GB7CIP<N3HYM<KE0GB<K3CHB<
LU9DCE
Sent: 201203/1600Z 42296@LU9DCE.TOR.BA.ARG.SOAM LinBPQ6.0.20
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ESTACION DE PACKET RADIO - BUENOS AIRES (GF05OM)
BOLETINES INFORMATIVOS PROGRAMADOS (BIP)
CASTILLOEDUARDO@OUTLOOK.COM.AR
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SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259
AM CST Thu Dec 03 2020
Valid 041200Z - 051200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS
THE WESTERN AND CENTRAL FL PANHANDLE...AND ACROSS THE COASTAL
CAROLINAS...
...SUMMARY... Isolated severe thunderstorms are possible portions
of the Florida Panhandle Friday afternoon, and across the coastal
Carolinas early Saturday morning.
...Synopsis... A positively tilted shortwave trough is forecast
to extend from the middle OH Valley into north TX early Friday
morning. This shortwave is then expected to progress quickly
eastward while pivoting to a neutral and then negative tilt. By
early Saturday morning, the expectation is for this shortwave to
be over the Mid-Atlantic States.
Surface low associated with this shortwave will likely be centered
near coastal MS/AL early Friday morning before quickly moving
northeastward into the Mid-Atlantic ahead of its parent shortwave.
As it does, an attendant cold front will sweep eastward/southeastward
across eastern portions of the Southeast, the FL Panhandle, and
much of the Mid-Atlantic. Two areas of potential severe weather
are possible, one across the FL Panhandle Friday afternoon and the
other over the central and eastern Carolinas early Saturday morning.
...FL Panhandle... Low to mid 60s dewpoints are expected
to be in place ahead of the cold front Friday morning into
Friday afternoon. Abundant cloud cover is expected, tempering
daytime heating, and lapse rates will be poor. Consequently,
despite favorable low-level moisture, instability will be modest
(i.e. MLCAPE less than 750 J/kg). Most of the better flow aloft and
vertical shear will be displaced north of any instability and/or
behind the front. However, there appears to be a relatively narrow
window where instability and vertical shear will overlap enough
to promote at least low-probability severe potential across the
western/central FL Panhandle Friday afternoon. In this area,
any more robust and persistent updraft could produce an isolated
damaging wind gusts and/or brief tornado.
...Mid-Atlantic... The shortwave is expected to mature as it
continues eastward into the Mid-Atlantic region, with this maturation
contributing to an increase in low to mid-level flow throughout its
eastern periphery. This enhanced flow aloft will spread into the
central and eastern Carolinas from 06Z to 12Z Saturday. Additionally,
favorable onshore trajectories will result in modest moisture
advection, with dewpoints likely in the low to mid 60s. As a
result, there will likely be enough instability and shear for a
few supercells ahead of the front, as well as strong storms along
the front. Damaging wind gusts appear to be the greatest threat,
but a tornado or two is also possible. Higher wind probabilities
may be needed in later outlooks if the probability for slightly
greater instability increases.
..Mosier.. 12/03/2020
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211
AM CST Thu Dec 03 2020
Valid 051200Z - 061200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY... Isolated lightning flashes are possible across the
Mid-Atlantic and central/southern Florida Peninsula on Saturday.
...Synopsis and Discussion... Majority of the medium-range forecast
guidance places a mature mid-latitude cyclone over the central
Mid-Atlantic States on Saturday morning. The only exception is
the ECMWF, which is more progressive and places the cyclone off
the northern Mid-Atlantic coast. This more progressive solution
takes the front offshore before the period begins, while the less
progressive solutions leave a small portion of the central/northern
Mid-Atlantic ahead of the front. Given the presence of very
strong low to mid-level flow, some low severe risk is feasible
across coastal NC and the VA Tidewater in the less progressive
solutions. However, forecast confidence is currently too low to
introduce an outlook area.
Mostly stable conditions are expected outside of the Mid-Atlantic
region. A few lightning flashes are possible across the central and
southern FL Peninsula as a front moves through. A few lightning
flashes are also possible across South TX as a shortwave trough
ejects northeastward out of central Mexico and across TX. Coverage
over South TX are currently expected to be less than 10 percent.
..Mosier.. 12/03/2020
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK
0346 AM CST Thu Dec 03 2020
Valid 061200Z - 111200Z
...DISCUSSION... A shortwave trough is expected to drop from the
northern Plains/Upper MS Valley into the Mid MS/Lower OH Valley
on D4/Sunday, continuing eastward through the TN Valley and into
Mid-Atlantic on D5/Monday. Upper ridging is anticipated across
the central and eastern CONUS in the wake of this shortwave from
D6/Tuesday through D8/Thursday. As a result, stable conditions are
anticipated across the eastern CONUS for the entire period.
Farther west, an upper low is forecast to develop on D4/Sunday or
D5/Monday across the Great Basin before moving southward off the
southern CA/Baja coast. Some severe could be possible when/if this
low ejects northeastward across Mexico into the southern Plains
late next week. However, the overall evolution of this low remains
uncertain and forecast confidence past D7/Wednesday is low.
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK
1253 AM CST Thu Dec 03 2020
Valid 031200Z - 041200Z
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR THE SAN DIEGO COUNTY
MOUNTAINS... ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR THE
MOUNTAINS OF EASTERN VENTURA AND WESTERN LOS ANGELES COUNTIES...
...CRITICAL FIRE WEATHER AREA FOR THE COASTAL MOUNTAINS OF SOUTHERN
CALIFORNIA...
...Synopsis... Early morning observations show a robust region
of surface high pressure over the central Rockies and into the
Great Basin. Aloft, an upper-level shortwave trough is evident
in water vapor imagery propagating southward through the Four
Corners region. The southward passage of the upper-level wave will
help the surface high maintain strength and shift southward this
morning through mid-day. The net result will be both augmented
surface pressure-gradient winds as well as increasing mid-level
winds across southern California. With antecedent hot and very
dry conditions already in place, critical to extremely critical
fire weather conditions are expected for portions of the coastal
mountains of southern California.
...Southern California... Critical fire weather conditions are
already ongoing at several observing sites across the higher
elevations of southern California this morning. Poor overnight
RH recoveries are yielding RH values between 10-15%, which are
expected to fall into the upper single digits for many locations
later today. Sustained winds at 20-25 mph are noted with gusts up
to 50-60 mph in a few locations.
Wind speeds will increase through the early to mid morning hours
as the regional pressure gradient increases with the southward
shift of the surface high. Additionally, the approach of the
aforementioned upper-level wave will help increase 850 mb winds
over the region. Widespread sustained winds at 25 to 35 mph are
expected with gusts up to 50-70 mph possible, especially across the
mountainous portions of San Diego county, eastern Ventura county,
and western Los Angeles county. These areas continue to show the
highest potential for sustained 30+ mph winds per early morning
guidance. Given the winds, dry fuels, and forecast RH values at or
below 10%, extremely critical risk areas have been maintained or
introduced in coordination with local WFOs.
The strongest winds are expected between 12 UTC to 18 UTC this
morning, but may remain elevated as late as 21 UTC for a few
locations. Heading into the evening hours, critical wind speeds
will likely continue over the highlighted region, and may persist
well into early Friday morning.
..Moore.. 12/03/2020
...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
0159 AM CST Thu Dec 03 2020
Valid 041200Z - 051200Z
...CRITICAL FIRE WEATHER AREA FOR THE COASTAL MOUNTAINS OF SOUTHERN
CALIFORNIA...
...Synopsis... The departure of a Four Corners upper-level wave
to the south into Mexico, along with height rises along the West
Coast, will weaken the surface high pressure somewhat over the Great
Basin through the day Friday. Despite a slowly waning surface high,
offshore pressure-gradient winds will likely remain in place over
southern California where very dry conditions have been ongoing for
the past several days. This will continue to support fire weather
concerns, though the magnitude and duration of the threat may not
be as robust as previous days.
...Southern California... Critical fire weather conditions will
likely be ongoing by 12 UTC Friday as sustained pressure-gradient
winds between 20-25 mph and RH values of 5-15% linger over
the higher elevation of southern CA. With the exit of more
favorable upper-level support to the south, the surface pressure
gradient between the Great Basin to the CA coast will likely
become more diurnally influenced with relaxing winds by 18-21
UTC Friday. However, ensemble guidance and hi-res deterministic
guidance continue to show the potential for a few hours of sustained
critical conditions within the higher terrain of southern CA
early Friday, warranting the critical delineation. Elevated fire
weather conditions should persist into Friday evening, and perhaps
into early Saturday morning, as the pressure gradient diurnally
re-intensifies. However, the potential for critical conditions
for Friday night/early Saturday remains somewhat unclear due to an
increase in model spread.
..Moore.. 12/03/2020
...Please see www.spc.noaa.gov/fire for graphic product...
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It is the business of little minds to shrink.
-- Carl Sandburg
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