LU9DCE > ALERT 16.08.18 09:15l 170 Lines 9547 Bytes #6 (0) @ WW
BID : 25550_LU9DCE
Subj: Storm Prediction Center 16 08 2018
Sent: 180816/0701Z @:LU9DCE.TOR.BA.ARG.SOAM #:25550 [TORTUGUITAS] $:25550_LU9DC
To : ALERT@WW
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ESTACION DE PACKET RADIO - BUENOS AIRES (GF05OM)
BOLETINES INFORMATIVOS PROGRAMADOS (BIP)
LU9DCE@GMX.COM - RF 145070 @ 1200 BAUD
AXIP NETROM -- LU9DCE.DYNU.COM UDP 10093
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100
AM CDT Thu Aug 16 2018
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHEAST KS AND NORTHEAST OK INTO FAR SOUTHWEST MO AND NORTHWEST
...SUMMARY... Severe thunderstorms will produce gusty, locally
damaging winds across parts of the central and southern Plains
this afternoon and evening. Additional strong thunderstorms are
expected from the middle Mississippi to the lower Ohio Valleys,
as well as across parts of central into northeast Oregon.
A midlevel trough across the Upper Midwest and Mid-MO Valley will
shift east across the Upper Great Lakes and Mid-MS/Lower-OH Valleys
today and tonight. At the surface, a warm and moist airmass, with
dewpoints in the mid 60s to mid 70s F will reside across eastern
portions of the central and southern Plains into the Mid-MS and
OH Valley regions. A somewhat diffuse and stalled frontal boundary
across northern OK into central MO and a southward-advancing cold
front across the Mid-MO Valley will be a focus for strong to severe
thunderstorms during the afternoon and evening. Additional strong
storms are possible in warm advection regime from southern IN/OH
into Middle TN.
Further west, a weak shortwave trough will move onshore the
Pacific Northwest coast after 00z. As the western upper ridge
migrates eastward, increasing southwesterly deep layer flow and
modest midlevel moisture across central into northeast OR could
be sufficient for isolated strong wind gusts with any storms that
...Portions of Central/Southern Plains Vicinity...
Forecast confidence is fairly low this morning as convective
evolution is uncertain and model guidance, both deterministic
and hi-res, is rather inconsistent. Storms may be ongoing at the
beginning of the period across parts of eastern KS. Additionally,
broken cloud cover may limit destabilization across parts of the
region initially. A stalled surface boundary was evident early
this morning across northern AR into northeast OK. This boundary may
be a focus of redevelopment later this afternoon. Furthermore, the
southward-advancing cold front also will be a potential candidate
for storm initiation and intensification. Given that one or both
of these boundaries may initiate storms today into this evening,
it is likely that the slight risk will need further refinement in
Uncertainty in convective initiation location aside, increasing
northwesterly shear on the southern periphery of the midlevel trough
will promote organized convection in a moderately to strongly
unstable airmass. Modest midlevel lapse rates will develop by
afternoon as midlevel cooling overspreads the region. Shear profiles
will be marginally favorable for supercells, but convection will
likely quickly become linear given the presence of the aforementioned
surface boundaries and likely downdraft-dominant storms in the
weak lapse rate/high PW environment. One or more bowing segments
is expected to track south/southeast across portions of eastern
KS into OK/southern MO/northern AR. Strong, locally damaging wind
gusts will be the main threat, though some hail is possible with
the strongest storms.
...Mid-MS/Lower OH Valley...
Several rounds of strong storms will be possible today in warm/moist
advection ahead of the approaching trough. Midlevel southwesterly
flow will increase to 25-35 kt and as moderate destabilization
occurs, some strong multicell clusters are possible. Isolated strong
wind gusts will be possible as weak low level winds and PW values
near 2 inches favor wet microbursts.
...Central into Northeast OR...
Isolated to scattered thunderstorms will develop during the late
afternoon into the evening hours as the upper ridge breaks down.
Strong mid-to-upper level southwesterly flow will result in fast
northeasterly storm motion. Furthermore, a deeply mixed and dry
sub-cloud layer will foster strong downburst wind potential.
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239
AM CDT Thu Aug 16 2018
Valid 171200Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE NORTHERN
ROCKIES AND FROM THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI
AND TENNESSEE VALLEYS AS WELL AS THE NORTHEAST STATES...
...SUMMARY... A few storms with locally strong to damaging wind
gusts and hail will be possible from Oklahoma through the lower
Mississippi and Tennessee Valleys. A few strong to severe storms
might occur from the Middle Atlantic into a portion of New England
as well as farther west over the northern Rockies.
Deamplifying lead shortwave trough will continue northeast through
New England early Friday with an upstream trough immediately on
the heels of this feature forecast to approach the Northeast States
Friday night. A positive-tilt shortwave trough will advance through
the middle to lower MS and TN Valleys during the day, while farther
west a shortwave trough will move through the northern Rockies. At
the surface a weak surface low will evolve over the lower Great
Lakes in association with the northern-stream upper trough. A cold
front will stretch southwest from the low through the OH Valley and
into MO and OK. Warm front extending eastward from the low should
move slowly north through southern New England. A lee trough will
become established east of the Appalachians.
...Southern Plains to lower Mississippi and Tennessee Valleys...
Storms may be ongoing early Friday over a part of this region and
especially the middle to lower MS Valley in vicinity of convectively
reinforced cold front and in association with vorticity maxima
rotating through the positive-tilt upper trough. South of this
activity, heating of the moist boundary layer will contribute to
moderate instability with 1500-2500 J/kg MLCAPE, with stronger
instability westward into the Plains where steeper mid-level lapse
rates will reside. Storms should redevelop along the front and
residual outflow boundaries during the afternoon. A belt of modest
(25-35 kt) winds in the 850-500 mb layer will exist within base
of the upper trough, and weak 0-6 km shear will promote multicell
storm modes. Nevertheless, a few instances of locally strong to
damaging wind gusts and hail may accompany some of the storms.
...Northeast States and Middle Atlantic regions...
Storms will likely be ongoing within plume of subtropical moisture
along warm conveyor belt from the Ohio Valley into a portion of the
Northeast States. Downstream from this activity and primarily east
of the Appalachians, some diabatic warming of the boundary layer
may result in moderate instability with up to 1500 J/kg MLCAPE
possible. Storms may redevelop over the northeast U.S. along
warm front, residual outflow boundaries from ongoing convection,
as well as farther south over the higher terrain of the central
Appalachians and spread east. Some augmentation of the vertical
wind profiles will occur in association with the northern-stream
shortwave trough and the migratory low-level jet, especially in
the vicinity of the warm front. However, primary uncertainty in
this region is extent of ongoing convection and clouds and the
potential impact on destabilization. Will therefore maintain the
marginal risk category this update.
Farther south across the Mid Atlantic, wind profiles will be weaker,
but greater destabilization potential suggests multicell storms
that move off the higher terrain or develop along lee trough may
become capable of producing a few instances of downburst winds
during the afternoon.
...Northern Rockies region...
Presence of steep mid-level lapse rates and ascent accompanying the
shortwave trough will promote destabilization, but instability will
remain marginal (at or below 500 J/kg) owing to limited low-level
moisture. Storms are expected to develop over the higher terrain
during the day and spread east. Inverted-V, deeply mixed boundary
layers will promote some risk for a few instances of downburst
winds from late afternoon through early evening.
...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind:
5% - Marginal Hail: 5% - Marginal
Put a pot of chili on the stove to simmer. Let it simmer. Meanwhile,
broil a good steak. Eat the steak. Let the chili simmer. Ignore it.
-- Recipe for chili from Allan Shrivers, former governor
\\\ Eduardo Castillo --- email@example.com --- http://lu9dce.dynu.com \\\
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