River Flood Warning 35, NWS Memphis, TN

Area Forecast Discussion
National Weather Service Memphis TN
314 PM CST Wed Feb 5 2020

.DISCUSSION...
Very difficult forecast for the Mid-South today. A deep trough
continues to dig across the central CONUS this afternoon, wrapping
up well into northern Mexico. Downstream of this trough, broad
southwesterly flow aloft is streaming Pacific moisture into the
Lower MS Valley. One shortwave trough is lifting across the
Arklatex and its influence is easily seen via the increasing radar
trends across the CWA. At the surface, a quasistationary front
extends from Yazoo City (MS), to Tupelo, to Tullahoma (TN). South
of this front, temperatures are near 70F with dewpoints in the
mid/upper 60s. To the north, much cooler air is locked in place
with current readings ranging from the upper 30s in northeast AR
and the MO Bootheel to the 40s and 50s across TN and north MS.

As we move through the early evening hours a surface low along the
cold front will zip northeast along the boundary. Short-term
guidance has been a bit aggressive in lifting the cold front
poleward ahead of the low and it still may occur to some degree.
The greatest severe weather threat will be confined to the area
along/south of the cold front storms will be able to root in the
boundary layer, tapping into SBCAPE near 1000 J/kg. Kinematics are
favorable for organized storms with a few embedded supercell
structures. Strong storm relative helicity in the warm sector will
promote rotating updrafts and the possibility of a few tornadoes.
These storms will also be capable of producing damaging wind and
marginally severe hail. Farther north, storms will remain more
elevated with the primary threat being small hail or perhaps gusty
winds.

Storms will exit to the east late this evening and we expect
occasional light rain for the most part for the remainder of
tonight and tomorrow. Temperatures have been lowered tomorrow to
account for cold advection, no insolation, and light
precipitation. Another challenging aspect of the forecast is the
potential for light wintry precipitation Thursday night. Cold air
aloft will overspread the area, quickly cooling the elevated warm
layer around/after 00z. While the dendritic growth zone (the -10
to -18 degree layer that favors the formation of dendrite ice
crystals) will not be saturated initially, we do expect another
wave of upper-level moisture to arrive, supporting a mix of rain
and snow in the evening. Some areas may change over to all snow
before precipitation ends, but we aren't expecting any significant
accumulations, which is usually the case where the cold air
chases the departing precipitation. The 90th percentile (worst
case) snow amounts are less than 1" area wide, with Memphis at
0.2" and areas in the TN Valley closer to 0.8". A significant
majority of the ECMWF ensemble members are on board with this
scenario as well. This forecast was played conservatively with
0.1" or less in most areas, but some areas (mainly in west TN)
could see a light dusting.

A brief dry period is expected Friday, although a few flurries
could persist into the morning. Temperatures will remain below
normal with highs in the 40s across most of the CWA. The global
models continue to show a quick-moving shortwave trough affecting
the Mid-South on Saturday. This system will suffer from limited
moisture, putting a cap on PoPs and QPF amounts. PoPs were
confined to only the Saturday period at this time. Dry weather is
anticipated again on Sunday, but we'll be right back into the rain
chances as we move into early next week.

The flow aloft will transition to quasi-zonal this weekend into
early next week as a deep low closes off over the Desert
Southwest. This trough will sit out west through Monday but is
forecast to move east early as a northern stream trough moves
across the northern Plains. The global models all indicate this
trough swinging across the Southern Plains at some point during
the middle of next week but differ on the timing by as much as 18
hours. High end chance PoPs were retained Tue-Wed to account for
this uncertainty. The global ensembles also indicate a significant
temperature variability next week so confidence remains low on the
potential for warm sector instability with this system.

MJ

&&

.AVIATION...
/18Z TAFs/

Basically a IFR or even LIFR day today with severe weather on the
horizon. Short range models show VCTS close to MEM around 21Z
today but the area of concern is TUP. Showers will likely end
around 08Z tomorrow. Expect N/NE winds around 6 to 10 kts with the
potential for MVFR ceilings at JBR by the end of the TAF period.

SGW

&&

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

&&

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Special Weather Statement
National Weather Service Memphis TN
208 PM CST Wed Feb 5 2020

ARZ027-035-036-048-TNZ088-052100-
Poinsett AR-St. Francis AR-Cross AR-Crittenden AR-Shelby TN-
208 PM CST Wed Feb 5 2020

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED UNTIL 300 PM CST
FOR...

Southeastern Poinsett County in eastern Arkansas...
Eastern St. Francis County in eastern Arkansas...
Southeastern Cross County in eastern Arkansas...
Northern Crittenden County in eastern Arkansas...
West central Shelby County in western Tennessee...

At 208 PM CST...a strong thunderstorm producing pea size hail or
larger and winds at least 40 mph was located over Widener, or near
Madison, moving northeast at 50 mph.

People in southeastern Poinsett...eastern St. Francis...southeastern
Cross...northern Crittenden and west central Shelby Counties should
monitor this storm closely.

LAT...LON 3552 9036 3546 9029 3544 9029 3544 9027
      3526 9006 3493 9068 3506 9083
TIME...MOT...LOC 2008Z 227DEG 43KT 3506 9068

KRF

Special Weather Statement
National Weather Service Memphis TN
243 PM CST Wed Feb 5 2020

MSZ007-008-010>012-052115-
Tunica MS-Coahoma MS-Panola MS-Tate MS-Quitman MS-
243 PM CST Wed Feb 5 2020

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED UNTIL 315 PM CST
FOR...

Southeastern Tunica County in northwestern Mississippi...
East central Coahoma County in northwestern Mississippi...
Panola County in northwestern Mississippi...
Southwestern Tate County in northwestern Mississippi...
Quitman County in northwestern Mississippi...

At 243 PM CST...a strong thunderstorm producing pea size hail or
larger and winds at least 40 mph was located near Lambert, or 13
miles east of Clarksdale, moving northeast at 65 mph.

People in southeastern Tunica...east central Coahoma...Panola...
southwestern Tate and Quitman Counties should monitor this storm
closely.

LAT...LON 3417 9052 3463 9022 3431 8976 3416 9011
      3416 9013 3415 9014 3407 9031 3407 9039
TIME...MOT...LOC 2043Z 221DEG 56KT 3417 9034

KRF