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LU9DCE > ALERT 01.12.20 16:03z 197 Lines 11061 Bytes #999 (0) @ WW
BID : 42136_LU9DCE
Read: GUEST
Subj: STORM PREDICTION CENTER 01 12
Path: HB9ON<IW8PGT<IZ3LSV<DB0ERF<DB0RES<ON0AR<GB7CIP<N7HPX<LU9DCE
Sent: 201201/1600Z 42136@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 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1147
PM CST Mon Nov 30 2020
Valid 011200Z - 021200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY... Severe thunderstorms are not expected across the
United States today.
...Discussion... As a deepening upper low moves slowly
north-northeastward across the Lower Great Lakes into the
Ottawa Valley, a short-wave trough in its wake -- digging
south-southeastward across the Rockies -- will evolve into a second
closed low through the second half of the period.
At the surface, an occluded low is progged to retrograde
northwestward into/across southwestern Quebec, while the trailing
cold front advances across the western Atlantic. Meanwhile,
a weak low is forecast to shift across the southern Plains, in
response to the evolving western upper low. High pressure will
prevail elsewhere.
Thunderstorm activity is forecast to be minimal across the CONUS
today; a few lightning flashes will be possible during the first half
of the period over eastern Maine, near the occluded surface system's
triple point. Showers and possibly an elevated thunderstorm or two
may also evolve late in the period over coastal portions of Texas, as
low-level theta-e advection increases atop a stable boundary layer.
In both areas, severe weather is not expected.
..Goss/Moore.. 12/01/2020
SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman
OK 1252 AM CST Tue Dec 01 2020
Valid 021200Z - 031200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE AND UPPER TX COAST AND FAR SOUTHWEST LA...
CORRECTED TO FIX GRAPHIC
...SUMMARY... Isolated strong to severe thunderstorms are possible
over the middle/upper Texas Coast and far southwest Louisiana
on Wednesday.
...Synopsis... A pair of upper cyclones are forecast to be embedded
within a larger cyclonic circulation over the Plains Wednesday
morning. The northernmost upper cyclone will likely be centered near
the WY/CO border while the southernmost upper cyclone will likely be
centered over the eastern TX Panhandle/western OK. The southernmost
cyclone is expected to slowly move eastward/northeastward over
OK while enhanced mid-level flow throughout its base spreads
northeastward into the mid MS Valley. The northernmost cyclone is
expected to move southwestward towards the Four Corners region.
At the surface, low associated with the southernmost upper cyclone is
forecast to begin the period over the TX/OK Red River Valley, before
gradually progressing northeastward while occluding. A cold front
extending southward from this low will move eastward/southeastward
across central and east TX, reaching the coast by Wednesday afternoon
and the TX/LA border Wednesday night.
...Middle/Upper TX Coast...Far Southwest LA... Upper 50s/low
60s dewpoints are expected to advect into the middle and upper
TX coast ahead of the approaching cold front, contributing to
modest instability as temperatures warm into the upper 60s/low
70s. Moderate southeasterly low-level winds are also anticipated
ahead of the front, resulting in looping low-level hodographs and
kinematic environment that supports low-level updraft rotation.
Given the modest instability, most deep updrafts will likely be
transient and disorganized. However, any more persistent updrafts
could become organized enough to produce damaging wind gusts and
perhaps a tornado.
..Mosier.. 12/01/2020
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0141
AM CST Tue Dec 01 2020
Valid 031200Z - 041200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY... Isolated thunderstorms are possible across portions
of the Lower Mississippi Valley and Southeast on Thursday.
...Synopsis... At the beginning of the period, a pair of upper
lows, one centered over northeast OK and the other over the central
NM/AZ, are expected to be embedded within an elongated upper trough
extending from the Mid MS Valley through the Southwest. This upper
troughing will likely be maintained throughout the period as the
easternmost upper low devolves into an open wave and moves across
the Mid MS Valley into the Lower OH Valley. Enhanced mid-level flow
attendant to this upper low/shortwave will spread northeastward
from the Southern Plains through the OH Valley.
The surface low associated with the eastern upper low is forecast
to begin the period over eastern OK. This low is expected to fill
throughout the day while a secondary low develops farther south over
the Lower MS Valley. Upper 50s/low 60s dewpoints are anticipated
ahead of this secondary low and attendant cold front. Daytime heating
will be tempered by abundant cloud cover, but enough low-level
moisture is expected to be in place to support modest instability
and the development of isolated thunderstorms. This instability will
likely be displaced south of the stronger low-level and mid-level
flow, limiting vertical shear and keeping severe potential very low.
..Mosier.. 12/01/2020
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK
0257 AM CST Tue Dec 01 2020
Valid 041200Z - 091200Z
...DISCUSSION... Most recent guidance from several deterministic
models suggests some severe potential may materialize across the
Southeast D4/Friday and Mid-Atlantic on D5/Saturday. These models
forecast a maturing mid-latitude cyclone moving through those
regions. However, previous runs do not show a mature system, with
most favoring a weaker, more progressive evolution. Additionally, the
ECMWF, which has shown more run-to-run consistency, is forecasting
mature low over the Southwest/northern Mexico which slowly drifts
eastward toward the southern Plains during the weekend. All of these
factor lead to a low forecast confidence for the weekend. Even with
these differences, mostly stable conditions appear likely beginning
D6/Sunday and continuing through early next week.
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK
0101 AM CST Tue Dec 01 2020
Valid 011200Z - 021200Z
...Synopsis... Early morning water-vapor imagery reveals an
upper-level trough that is beginning to dig southward into
the Central Rockies. This feature will drive a couple areas of
fire weather concerns for today by 1) reinforcing surface high
pressure across the Northwest and 2) supporting a deepening lee
trough and a subsequent southward surge of cold air along the High
Plains. Elsewhere, recent widespread precipitation and cooler air
behind a strong surface low over the Northeast will negate any fire
weather potential.
...Southern California... Recent guidance remains in reasonably
good agreement regarding the strengthening of surface high pressure
over the Pacific Northwest/northern Great Basin today through early
Wednesday. This will gradually augment offshore pressure-gradient
winds over the next 24 hours for the southern CA coast. Early
morning surface observations show ongoing elevated (with a few
stations reporting critical) conditions within the higher terrain of
southern CA. These conditions should largely persist with a gradual
increase in coverage through 12 UTC Wednesday. Critical conditions
remain most likely across northern Los Angeles and Ventura counties
early Wednesday morning, but should be localized enough to preclude
the need for a critical delineation.
...Southeast New Mexico... Westerly downslope winds are forecast to
increase across eastern NM and far western TX ahead of a southward
surging cold front and in response to a deepening lee low. Sustained
winds near 15 mph appear likely this afternoon with gusts upwards
of 25-30 mph possible. Downslope warming and drying, coupled
with deep boundary-layer mixing, should yield RH values in the low
teens - especially closer to terrain features. While a few hours
of elevated conditions appear likely prior to the frontal passage,
recent reports from the region suggest that fuels are only modestly
receptive with ERC values near or only slightly above seasonal
normal. Due to the meager nature of the fuels, highlights are not
introduced in this outlook.
..Moore.. 12/01/2020
...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
0149 AM CST Tue Dec 01 2020
Valid 021200Z - 031200Z
...Synopsis... An upper-level trough is expected to stall over the
south-central CONUS through the day Wednesday. An embedded shortwave
trough orbiting around the western periphery of the main low will
reinforce surface high pressure over the northern Great Basin through
the day. As the surface high shifts southward, pressure-gradient
winds will likely increase across southern California and support
a continuation of elevated, to potentially critical fire weather
conditions for higher elevations. Elsewhere, cooler air along with
precipitation chances will limit fire weather concerns.
...Southern California... Dry conditions are expected to persist
across southern CA through Wednesday with little to no moisture
return and poor RH recovery for the higher elevations. Recent
guidance has come into better agreement regarding the evolution
of the surface ridge for Wednesday and Thursday as it builds
into the Great Basin. The DAG-LAX pressure gradient is forecast
to increase from around 5-8 mb Wednesday morning to 8-11 mb by
around 12 UTC Thursday (with a slight relaxing of the gradient
around mid-day). Areas of elevated conditions, along with pockets
of critical conditions, will likely be ongoing at the period
and may increase in coverage through early Thursday morning.
Persistent critical conditions will likely remain relatively
isolated through mid-morning Thursday when the pressure gradient
is forecast to be strongest (see the recent Days 3-8 Fire Weather
Forecast for details regarding Thursday). As with Tuesday, ensemble
guidance suggests the most likely location for persistent critical
conditions will be across northern Los Angeles and Ventura counties.
Since the strongest winds and highest potential for widespread
critical conditions are forecast to occur after the Day 2 period,
no critical delineations are introduced for this outlook.
..Moore.. 12/01/2020
...Please see www.spc.noaa.gov/fire for graphic product...
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