Severe Thunderstorm Warning 149, NWS Memphis, TN

Area Forecast Discussion
National Weather Service Memphis TN
1234 PM CDT Sun May 3 2020

.UPDATE...

Update for 18Z TAF issuance.

&&

.PREV DISCUSSION... /issued 1028 AM CDT Sun May 3 2020/

It's generally quiet across the Mid-South at this time, but we're
continuing to monitor a cluster of strong to severe thunderstorms
moving across southwest MO. These storms are expected to continue a
rapid eastward progression throughout the day ahead of a shortwave
trough over the Central Plains. A stratocumulus deck is filling in
across the region this morning, but the latest guidance continues to
indicate destabilization this afternoon with temperatures warming
into to 80F+ in most areas. MLCAPE near 2000 J/kg is anticipated
this afternoon, mainly along north of I-40 as moisture pools ahead
of the approaching cold front. Deep-layer shear will be strong with
0-6km BWD of 35-45 kts. This should help maintain the MCS despite it
running into a bit of a capping inversion. Downshear Corfidi vectors
indicate a propagation speed exceeding 50 mph so this system won't
take long to move through the CWA. Damaging winds will be the
primary concern, especially across the Bootheel and portions of west
TN.

PoPs were increased for this afternoon to account for the more
recent model trends and anticipated MCS. Temperatures were also
increased a few degrees in the northern portion of the CWA where
surface obs are already in the mid 70s.

MJ

PREV DISCUSSION... /issued 353 AM CDT Sun May 3 2020/

DISCUSSION...
Currently...Mild across the Mid-South early this morning with
light south winds and temps ranging from the upper 50s along the
TN River to the upper 60s across the Delta. Humidity levels have
climbed over the past day or two with dewpoints in the upper 50s
to lower 60s. Skies are mostly clear and a cold front is situated
from KIND-KSTL-KOKC.

Today and tonight...Cold front will sag south during the day
while a fast moving shortwave moves across the Middle MS Valley by
noon and into the Ohio Valley by this evening. Expect interaction
between these features to result in convective development early
this morning across SE KS/SW MO spreading east/southeast during
the day. A marginally unstable airmass with SBCAPES between
1000-2000 j/kg will develop today across northern sections of the
Mid-South. Steep mid level lapse rates are in place as evidenced
not only by sounding data but also periods of ACCAS clouds over
the last 24 hours. 0-6km shear of 40-50 kts will overspread
northern parts of the Mid-South as the shortwave passes by to the
north. The cap around 700 mb is pretty substantial early on
though model soundings indicate some weakening by this afternoon.
Latest CAMs indicate multi cell clusters working into northern
parts of the Mid-South starting as early as 11 am pushing
east/southeast during the afternoon. Given that some ingredients
are in place some strong to perhaps severe storms are possible.
Large hail and damaging wind would be the threat with any severe
storms. As the upper support races east expect convection
associated with the front drifting south across the Mid-South to
weaken tonight. By Monday morning the front will be located across
North MS.

Monday and Monday night...The front will remain stalled for a
while Monday with a few showers around in the morning. Monday
afternoon the next shortwave will start racing across the plains
and into the Middle MS Valley with surface low pressure tracking
from the Red River Valley ENE toward North AR/SW MO and the
stalled front across the Mid-South will start to lift NE. Expect
convection to develop across MO during the day and eventually
slide east-southeast along the boundary across the Mid-South.
Steep mid-level lapse rates, adequate surface based instability
south of the boundary and 0-6 km shear values increasing to over
50kts could lead to a few severe storms mainly over NE AR, the MO
Bootheel and NW TN. Damaging winds and hail would be the main
threats. The severe weather threat looks like later in the
afternoon into the evening hours before the shortwave tracks east
and the upper support wanes.

Tuesday...The trailing cold front drifts southeast during the day.
There will be a few showers and perhaps a thunderstorm as the
front tracks through but the forcing is weak and a cap will be in
place. Have decided to pull the mention of strong storms from the
HWO for Tuesday afternoon.

Wednesday and Thursday...This beautiful spring still has legs. Cool
high pressure with deep NW flow builds in with well below normal
temperatures. Some location will see some lows in the 40s
especially Thursday morning.

Friday and Saturday...This pattern is looking like fall with a
large upper low dropping into the Great Lakes by the end of the
week. A cold front front will bring rain chances to the Mid-South
Friday followed by an unseasonable, almost chilly. airmass for
the weekend. Expect highs in the 60s with widespread lows in the
40s. Would not be surprised if one of our cooler locations dips to
39F. FYI...average highs for next weekend for Memphis are
approaching 80F with average lows around 60F.

SJM

&&

.AVIATION...
/18Z TAFs/

Active weather period for most of our TAF sites this forecast cycle.
Line of TSRA will move rapidly east near the AR/MO and TN/KY
borders, and may affect northern TAF sites with TSRA and gusty
OUTFLOW winds. Surface cold front will move through overnight,
continuing the threat for at least SHRA at all except KTUP. Lower
cigs also expected with frontal boundary, will take to lower bound
of MVFR for now. SSW surface winds, some gusty, will swing to N/NE
following front passage.

GW

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.

&&

Hazardous Weather Outlook...UPDATED
National Weather Service Memphis TN
1144 AM CDT Sun May 3 2020

ARZ009-018-026>028-035-036-048-049-058-MOZ113-115-MSZ001>017-
020>024-TNZ001>004-019>022-048>055-088>092-041100-
Alcorn-Benton MS-Benton TN-Calhoun-Carroll-Chester-Chickasaw-Clay-
Coahoma-Craighead-Crittenden-Crockett-Cross-DeSoto-Decatur-
Dunklin-Dyer-Fayette-Gibson-Greene-Hardeman-Hardin-Haywood-
Henderson-Henry-Itawamba-Lafayette-Lake-Lauderdale-Lee AR-Lee MS-
Madison-Marshall-McNairy-Mississippi-Monroe-Obion-Panola-Pemiscot-
Phillips-Poinsett-Pontotoc-Prentiss-Quitman-Shelby-St. Francis-
Tallahatchie-Tate-Tippah-Tipton-Tishomingo-Tunica-Union-Weakley-
Yalobusha-
1144 AM CDT Sun May 3 2020

This hazardous weather outlook is for portions of East Arkansas...
the Missouri Bootheel...North Mississippi...and West Tennessee.

.DAY ONE...This Afternoon and Tonight

Confidence is increasing that a cluster of strong to severe
storms will affect northeast Arkansas, the Missouri Bootheel, and
northwest Tennessee this afternoon. Damaging winds are the
primary hazard with large hail being a secondary concern. A Severe
Thunderstorm Watch is in effect from Harrisburg, to Brownsville,
to Decaturville through 6 PM.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

A few strong to severe storms are possible along and north of the
Tennessee and Mississippi state line late Monday afternoon into
Monday evening. Best chances for severe storms will be across
Northeast Arkansas, the Missouri Bootheel and Northwest Tennessee.
Damaging winds and large hail are the main threats.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed this afternoon. Please
relay any information about observed severe weather to the NWS
while following all local, state, and CDC guidelines.

MJ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEMPHIS TN
205 PM CDT SUN MAY 03 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0202 PM     TSTM WND DMG     BROOKLAND               35.90N  90.58W
05/03/2020                   CRAIGHEAD          AR   SOCIAL MEDIA

            TREE DOWN ON SAGE MEADOWS GOLF COURSE.

&&

SMW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEMPHIS TN
214 PM CDT SUN MAY 03 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0210 PM     HAIL             LAKE CITY               35.82N  90.45W
05/03/2020  E1.00 INCH       CRAIGHEAD          AR   TRAINED SPOTTER

            HAIL TO 1 INCH REPORTED BY TRAINED SPOTTER.

&&

SMW

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