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LW3DBH > ALERT 07.04.20 02:30z 105 Lines 5548 Bytes #999 (0) @ WW
BID : 60610_LW3DBH
Read: GUEST
Subj: Storm Prediction Center 06 04
Path: HB9ON<IW8PGT<LU4ECL<LW3DBH
Sent: 200407/0208Z @:LW3DBH.1744.BA.ARG.SA #:60610 [MORENO] FBB7.00i $:60610_LW
From: LW3DBH@LW3DBH.1744.BA.ARG.SA
To : ALERT@WW
_ __ _______ ____ ____ _ _
| |\ \ / /___ /| _ \| __ )| | | | BBS
| | \ \ /\ / / |_ \| | | | _ \| |_| | MORENO
| |__\ V V / ___) | |_| | |_) | _ | ARGENTINA
|_____\_/\_/ |____/|____/|____/|_| |_|
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MD 0290 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEAST
SOUTH DAKOTA...SOUTHEAST NORTH DAKOTA...WEST-CENTRAL MINNESOTA
Mesoscale Discussion 0290 NWS Storm Prediction Center Norman OK
0753 PM CDT Mon Apr 06 2020
Areas affected...northeast South Dakota...southeast North
Dakota...west-central Minnesota
Concerning...Severe potential...Watch unlikely
Valid 070053Z - 070330Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated marginally severe hail is possible this evening
from northeast South Dakota into west-central Minnesota. A few
strong wind gusts may occur as well.
DISCUSSION...Isolated cells continue to form west of the ABR
area downstream of the steeper low-level lapse rates and where
boundary-layer dewpoints in the lower 50s F are contributing to
MUCAPE up to 1500 J/kg. The 00Z ABR sounding shows steep lapse
rates aloft, 50 kt 0-6 km shear and elongated hodographs aloft. This
should be enough to sustain a few strong or marginally severe cells.
Gradual height falls/cooling aloft will continue through tonight,
while surface convergence near the low moves east across northern
SD and into MN by 09Z. Given increasing lift, a gradual increase
in storm coverage is expected. Precipitable water values of 0.75"
or less further suggests a limited severe threat.
..Jewell/Grams.. 04/07/2020
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MPX...FGF...ABR...BIS...
LAT...LON 44789831 44589905 44899952 45329975 45749971 46389851
46829714 46689622 46259586 45669595 45219645 44789831
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747
PM CDT Mon Apr 06 2020
Valid 070100Z - 071200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS
PARTS OF THE EASTERN DAKOTAS INTO WEST CENTRAL MINNESOTA...AND
ACROSS PARTS OF NORTHERN ILLINOIS INTO NORTHERN INDIANA...ADJACENT
SOUTHERN MICHIGAN...AND NORTHWEST OHIO...
...SUMMARY... A few strong storms may impact parts of the eastern
Dakotas into west central Minnesota, and a corridor from northern
Illinois into northwest Ohio, this evening into the overnight hours.
Some of these may be accompanied by at least some risk for severe
hail and strong surface gusts.
...01Z Outlook Update...
...Northern Plains into upper Mississippi Valley vicinity...
A vigorous short wave impulse, on the leading edge of larger-scale
troughing progressing across the Canadian Prairies, appears likely to
continue eastward, mainly north of the international border area.
However, one or two more subtle perturbations, emerging from
larger-scale troughing over parts of the West, are accelerating
east-northeast of the Wyoming Rockies, through portions of the
mid Missouri Valley, and will contribute to increasing mid-level
height falls and a continuing transition to cyclonic flow across the
remainder of the Dakotas into the upper Mississippi Valley overnight.
Isolated thunderstorm activity has recently initiated to the
west-northwest of Aberdeen in response to these developments,
and lift associated with related low-level warm advection, to the
northeast of a weak low center within lee surface troughing.
Although surface dew points are modest, and considerable
inhibition remains, models indicate that moistening will occur
atop the decoupling boundary layer associated with low-level jet
strengthening during the next few hours. In the presence of very
steep lower/mid tropospheric lapse rates, this is expected to
be sufficient to contribute to most unstable CAPE in excess of
1000 J/kg. Aided by strong shear within the convective layer,
a couple of vigorous storms capable of producing severe hail may
be possible ahead of a southeastward advancing cold front, before
large-scale ascent contributes to increasingly widespread convection,
and east-northeastward destabilization becomes insufficient to
maintain convective intensity.
...Southern portions of the Great Lakes region... Latest
observational data continue to support model output suggesting
potential for increasing thunderstorm activity this evening into the
overnight hours, along a developing warm frontal zone across southern
portions of the Great Lakes region. This is expected to be aided
by lift associated with a subtle short wave impulse now migrating
east-southeast of the Wisconsin/Illinois state border vicinity,
around the crest of broad mid-level ridging. Further aided by
elevated moisture return, and lift associated with low-level warm
advection, accompanying a 30 kt west-southwesterly 850 mb jet, it
still appears that destabilization and shear may become marginally
sufficient to support organized thunderstorm activity posing some
risk for severe hail and wind. Probabilities for any such activity
seem likely to increase across parts of northern Illinois into
northwest Indiana by 05-06Z, before spreading east-southeastward
overnight.
..Kerr.. 04/07/2020
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Shedenhelm's Law:
All trails have more uphill sections than they have downhill sections.
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