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LU9DCE > ALERT 24.12.20 17:42z 260 Lines 13664 Bytes #999 (0) @ WW
BID : 385_LU9DCE
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Subj: STORM PREDICTION CENTER 24 12
Path: HB9ON<IW0QNL<VE2PKT<K5DAT<N7HPX<LU9DCE
Sent: 201224/1700Z 385@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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WW 517 TORNADO AL FL LA MS CW 240740Z - 241700Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 517
NWS Storm Prediction Center Norman OK 140 AM CST Thu Dec 24 2020
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of Southern Alabama Western Panhandle
of Florida A small part of southeastern Louisiana Southeastern
Mississippi Coastal Waters
* Effective this Thursday morning from 140 AM until 1100 AM CST.
* Primary threats include... A couple tornadoes possible Isolated
damaging wind gusts to 70 mph possible
SUMMARY...A band of thunderstorms will proceed eastward across the
watch area through late morning, with the potential for widely
spaced, short-lived tornadoes, in marginal instability but very
favorable wind fields.
The tornado watch area is approximately along and 55 statute miles
north and south of a line from 45 miles west northwest of Gulfport
MS to 20 miles east northeast of Crestview FL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU7).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable
for tornadoes and severe thunderstorms in and close to the
watch area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements and
possible warnings.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 516...
AVIATION...Tornadoes and a few severe thunderstorms with hail surface
and aloft to 0.5 inches. Extreme turbulence and surface wind gusts
to 60 knots. A few cumulonimbi with maximum tops to 450. Mean storm
motion vector 25035.
...Edwards
WW 0517 Status Updates
STATUS REPORT ON WW 517
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SSE ASD TO
50 WNW GZH.
..SMITH..12/24/20
ATTN...WFO...MOB...LIX...JAN...
STATUS REPORT FOR WT 517
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ALC003-013-025-035-039-041-053-097-099-129-241040-
AL . ALABAMA COUNTIES INCLUDED ARE
BALDWIN BUTLER CLARKE CONECUH
COVINGTON CRENSHAW ESCAMBIA MOBILE
MONROE WASHINGTON
FLC033-091-113-241040-
FL . FLORIDA COUNTIES INCLUDED ARE
ESCAMBIA OKALOOSA SANTA ROSA
MSC039-047-059-241040-
MS . MISSISSIPPI COUNTIES INCLUDED ARE
GEORGE HARRISON JACKSON
WW 0516 Status Updates
STATUS REPORT ON WW 516
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SE 7R4 TO
45 ESE LFT.
WW 516 WILL BE ALLOWED TO EXPIRE AT 240800Z.
..SMITH..12/24/20
ATTN...WFO...LCH...LIX...JAN...
STATUS REPORT FOR WT 516
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
LAC005-007-063-093-099-101-105-117-240800-
LA . LOUISIANA PARISHES INCLUDED ARE
ASCENSION ASSUMPTION LIVINGSTON ST. JAMES
ST. MARTIN ST. MARY TANGIPAHOA WASHINGTON
GMZ455-240800-
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY
LA OUT 20 NM
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER
TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON
COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE
THUNDERSTORM AND TORNADO WATCHES.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1137
PM CST Wed Dec 23 2020
Valid 241200Z - 251200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST
SOUTH CAROLINA...EASTERN NORTH CAROLINA TO SOUTHEAST VIRGINIA...
...SUMMARY... Severe thunderstorms are expected across the Carolinas
and Mid Atlantic region later this afternoon and evening. A few
severe thunderstorms are also possible across portions of southeast
Alabama, southwest Georgia, and Florida.
...Middle Atlantic/Southeast...
Late-evening water-vapor imagery depicts an expanding/thickening
band of cloudiness across the Arklatex region, indicative of
increasing large-scale ascent ahead of a strong short-wave trough.
Intense mid-level height falls will spread across the Gulf States/TN
Valley region during the day as 130kt 500mb speed max translates
across northern AL into the southern Appalachians by 25/00z. While
the surface reflection in response to this feature will not be
particularly deep, a surface low should track north-northeast from
GA into the eastern WV Panhandle by early evening. As this occurs,
low-level trajectories will become more favorable for Atlantic
moisture to advance inland across Coastal Carolinas as a warm front
lifts to near the VA/NC border at 25/00z, then into the Delmarva
later in the evening. This warm sector advancement will allow for
modest destabilization that will support robust updrafts ahead of
the surging cold front.
Early in the period, a frontal squall line should be ongoing from
AL to extreme southeast LA. This activity may be severe at daybreak,
but higher buoyancy will be noted south of the FL Panhandle which may
ultimately lead to the strongest storms gradually focusing offshore
with time. However, by mid-late afternoon, instability should improve
markedly along the SC/NC Coast as intense southerly low-level flow
strengthens ahead of the short wave. Forecast soundings depict
1km flow on the order of 60kt with MUCAPE in excess of 1000 J/kg
at ILM by evening. Intense shear and modest surface-based buoyancy
suggest there is a concern for tornadoes with supercells later this
afternoon/evening. Latest high res guidance support a considerable
amount of pre-frontal warm-advection convection with supercell
structures spreading inland by 21z. Otherwise, some tornado threat
will be noted with embedded circulations along the frontal squall
line. Damaging winds are also expected with the linear MCS as it
spreads east.
..Darrow/Gleason.. 12/24/2020
SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1245
AM CST Thu Dec 24 2020
Valid 251200Z - 261200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY... Thunderstorms are not expected on Friday.
...Synopsis... A deep upper trough and embedded closed circulation
will be in place over the eastern CONUS early Friday morning. This
upper trough is forecast to progress northeastward, moving through
the Mid-Atlantic and ending the period with strong negative tilt from
eastern Ontario/western Quebec to off the NC coast. Upper ridging
will also be in place west of this trough, from northern Mexico
into Alberta. This ridge is expected to progress eastward into
the High Plains while dampening. Farther west, a shortwave trough
is expected to move into the Pacific Northwest late in the period.
At the surface, low associated with the eastern CONUS trough will
begin the period over eastern Ontario/southern Quebec. A cold front
will extend southeastward from this low to just off the southern New
England coast before arcing more southward. With the front already
offshore by early Friday morning and stable conditions in its wake,
no thunderstorms are expected across the central and eastern CONUS.
Strong forcing for ascent and cold temperatures aloft will accompany
the shortwave trough approaching the Pacific Northwest, and a
lightning flash or two may occur in the deeper convection within
the frontal band offshore. However, any lightning is not expected
to continue once the band moves onshore.
..Mosier.. 12/24/2020
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215
AM CST Thu Dec 24 2020
Valid 261200Z - 271200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY... Thunderstorms are not expected on Saturday.
...Synopsis... Modest upper ridging is forecast to be in place
over the High Plains early Saturday, with a shortwave trough likely
centered west of this ridge over the interior Pacific Northwest. This
shortwave trough is expected to continue eastward during the period,
reaching the northern/central Plains by early Sunday morning. Cold
temperatures aloft will accompany this shortwave, but low levels
are expected to be too cold and dry to produce buoyancy.
Surface lee troughing will deepen ahead of the shortwave trough,
with eventual cyclogenesis over the central High Plains. Resulting
surface low will likely then move eastward/northeast across KS,
reaching the Mid MO Valley by Sunday morning. Cold front attendant
to the surface low will sweep across the central Plains, but the
dearth of low-level moisture will result in stable conditions.
..Mosier.. 12/24/2020
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK
0333 AM CST Thu Dec 24 2020
Valid 271200Z - 011200Z
...DISCUSSION... A shortwave trough is currently expected
to move quickly eastward from the northern/central Plains
through the mid/upper MS Valley, OH Valley and Upper
Great Lakes on D4/Sunday. Surface low associated with this
shortwave will take a similar path with an attendant cold front
sweeping eastward/southeastward across the OH,TN, and Lower MS
Valleys. Limited low-level moisture will likely preclude thunderstorm
development along the front.
Another northern-stream shortwave trough will follow quickly behind
the initial shortwave, moving through the northern Plains/Upper
MS Valley late D4/Sunday and early D5/Monday. A third, more
substantial southern-stream shortwave is currently forecast to
move across the Southwest/Four Corners on D5/Monday and into the
Plains on D6/Tuesday. Model guidance continues to struggle with both
model-to-model and run-to-run consistency regarding the evolution
of this system. Even with thee inconsistencies, the overall strength
of the system suggests some severe storms will be possible if enough
moisture return precedes it.
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK
0118 AM CST Thu Dec 24 2020
Valid 241200Z - 251200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...
...Synopsis... A highly amplified, large-scale upper trough over
the central CONUS will evolve into a closed low as it moves slowly
towards the eastern states today. An upper ridge will build over
much of the western CONUS, as a shortwave trough moves across
southern/central CA and parts of the Southwest this evening and
tonight. A strong surface high will remain centered over the Great
Basin this morning, before slowly weakening through the day.
...Southern California... An enhanced surface pressure gradient
should support continued strong/gusty winds around 20-30 mph this
morning, mainly across the mountains/foothills of coastal southern
CA. Locally higher gusts to 40-50 mph will remain possible in favored
terrain/passes as well. This pressure gradient will gradually relax
by midday, with a corresponding decrease in wind speeds expected. RH
values will remain lowered in the 5-15% range for many areas owing
to poor recovery early this morning and continued mixing of the
boundary layer. The ongoing critical delineation has been maintained
for parts of southern CA with no changes, as critical conditions
appear likely to persist in the presence of very dry fuels for at
least a few hours this morning.
...Oklahoma/Texas... Strong/gusty northwesterly winds will likely
develop across parts of the southern Plains today, as enhanced flow
at mid levels on the back side of the upper trough/low reaches the
surface through diurnal mixing of the boundary layer. Sustained
winds of 15-25 mph should occur, with higher gusts possible. Even
though surface temperatures should remain rather cool behind a
prior frontal passage, RH values should lower to around 15-25%,
which will support widespread elevated conditions for a few hours
this afternoon from parts of the TX Panhandle into southern OK
and TX. Marginal fuel receptiveness across most of these areas and
the limited spatial and temporal occurrence of critical conditions
preclude the introduction of a critical area at this time.
..Gleason.. 12/24/2020
...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
0118 AM CST Thu Dec 24 2020
Valid 251200Z - 261200Z
...NO CRITICAL AREAS...
...Synopsis... A large-scale upper trough/low should move slowly
east-northeastward across the eastern states on Friday. In its wake,
an upper ridge should prevail over most of the western/central
CONUS, while a shortwave trough moves across parts of the Pacific
Northwest. At the surface, weak lee troughing may encourage
modest low-level downslope flow in the presence of marginally
lowered RH values across parts of the southern High Plains Friday
afternoon. Regardless, the occurrence of elevated conditions across
this area appears too limited in both space and time to include an
elevated delineation.
..Gleason.. 12/24/2020
...Please see www.spc.noaa.gov/fire for graphic product...
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We knew from experience that the essence of communal computing,
as supplied by remote-access, time-shared machines, is not just
to type programs into a terminal instead of a keypunch, but to
encourage close communication.
-- Dennis Ritchie
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