Storm Prediction Center Forecast


RSS Mesoscale Discussions from Storm Prediction Center

SPC - No watches are valid as of Fri Feb 22 22:24:01 UTC 2019

No watches are valid as of Fri Feb 22 22:24:01 UTC 2019.


SPC MD 120

MD 0120 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN MISSISSIPPI...PORTIONS OF EASTERN LOUISIANA
MD 0120 Image


Mesoscale Discussion 0120
NWS Storm Prediction Center Norman OK
0344 PM CST Fri Feb 22 2019

Areas affected...Southern Mississippi...Portions of Eastern
Louisiana

Concerning...Severe potential...Watch unlikely 

Valid 222144Z - 222345Z

Probability of Watch Issuance...5 percent

SUMMARY...A few strong/marginally severe storms are possible through
early evening. A few damaging wind gusts are possible. No watch is
anticipated.

DISCUSSION...Current KLIX radar imagery shows two stronger,
diurnally-driven thunderstorms ongoing in southern
Mississippi/eastern Louisiana. These cells are south of a warm
front/differential heating boundary currently situated from
southeast Texas to east-central Mississippi. The warm/moist airmass
supports MLCAPE values of 500-1000 J/kg. Though relatively strong
deep layer shear is in place -- 50-55 kts -- weak mid-level lapse
rates are limiting overall storm intensity. These thunderstorms have
exhibited some weak mid-level rotation, but weak low-level wind
fields should limit the tornado risk unless storms interact with the
boundary to the north. Damaging wind gusts appear to be the primary
threat with this activity. No watch is anticipated.

..Wendt/Grams.. 02/22/2019

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...JAN...LIX...

LAT...LON   30929140 31329108 31559054 31729011 31708974 31358944
            30958939 30778956 30618991 30309030 30199086 30429128
            30689145 30929140 

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SPC Feb 22, 2019 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0143 PM CST Fri Feb 22 2019

Valid 222000Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION
OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY REGION...

...SUMMARY...
A low probability risk exists for severe storms this afternoon
through tonight from east Texas across the Lower Mississippi Valley.

...Discussion...

Previous forecast remains on track with at least a marginal risk for
severe weather as storms interact with a southwest-northeast
oriented boundary from east TX into southern AR, northern LA and MS.

..Dial.. 02/22/2019

.PREV DISCUSSION... /ISSUED 1030 AM CST Fri Feb 22 2019/

...East TX to Lower MS Valley...
Lee cyclogenesis is expected across northeast NM, within the
left-exit region of a strengthening mid-upper jet streak that will
rotate northeastward from northern Mexico to west central TX by
early morning Saturday. The warm/richly moist sector consisting of
mean mixing ratios around 14 g/kg as sampled by the 12Z New Orleans
sounding will generally remain across southern portions of LA/MS
this afternoon before advancing north across the Lower MS Valley
tonight in response to the cyclogenesis. A couple CAMs (WRF-NSSL and
HRRR) suggest late afternoon/early evening convection should
initiate near the front but struggle to intensify as warm
advection/mean wind profiles would likely result in activity
developing to the cool side of the boundary and becoming elevated.
There will be sufficient vertical shear for a couple supercell
structures, with an attendant threat for marginally severe hail,
along with isolated damaging wind gusts and perhaps a brief tornado
with any storms close to the warm front.  

By tonight, steeper midlevel lapse rates will begin to overspread
the low-level moisture from east TX to the Ark-La-Miss, as vertical
shear increases in advance of the ejecting midlevel trough and
surface cyclone. Isolated large hail will be possible with the
slightly elevated storms, with sufficient effective bulk shear
(generally 45-55 kt) for a couple supercell structures. The more
concentrated convection tonight into early morning should be along
the warm conveyor belt from southern/eastern AR into middle TN. The
steeper lapse rates to the west will also likely be associated with
mid-level convective inhibition, which could delay the majority of
stronger storm development in east TX until the D2 period as forcing
for ascent increases.

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SPC Day 2 Fire Weather Outlook

SPC Day 2 Fire Weather Outlook
          
Day 2 Fire Weather Outlook Image
Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0126 PM CST Fri Feb 22 2019

Valid 231200Z - 241200Z

...CRITICAL FIRE WEATHER AREA FOR SOUTHEASTERN NEW MEXICO THROUGH
SOUTH TEXAS...

Northward expansions of critical fire weather delineations were made
across southeastern New Mexico and the adjacent Texas South Plains. 
Latest guidance indicates very strong low-level flow across these
areas, with 30-45 mph gusts and RH values below 15% during the
afternoon.  Some of these conditions may spread eastward into
western north Texas and vicinity, although guidance depicts slightly
higher RH values and slightly less-favorable fuels compared to areas
farther west.  To accommodate for the modest degree of uncertainty,
decided to expand the critical area east toward the US-283 corridor
with the expectation that briefly critical atmospheric conditions
will probably be observed to the east and longer-duration critical
conditions expected to the west.

..Cook.. 02/22/2019

.PREV DISCUSSION... /ISSUED 0157 AM CST Fri Feb 22 2019/

...Synopsis...
A vigorous shortwave trough and associated intensifying surface
cyclone will traverse the south-central CONUS during Day 2/Saturday.
With a mature surface cyclone in place across the Southern Plains,
very strong, dry westerly flow will foster very favorable conditions
for fire spread across portions of the southern High Plains during
the afternoon hours with dry, fine fuels in place to support
wildfire growth. 

...Far southeast New Mexico into much of western into central
Texas...
With the aforementioned surface cyclone moving across the Southern
Plains, and an associated dryline mixing eastward into central Texas
during the afternoon of Day 2/Saturday, very strong westerly winds
(25+ mph) will ensue across southeast New Mexico into much of
western into central Texas, amidst widespread 20% RH, where an
elevated delineation was introduced. A critical delineation was
added from the Davis Mountains, eastward across much of the Edwards
Plateau, where temperatures climbing will over 60F, and RH dropping
at/below 15% will be common. By nightfall, cooling temperatures and
RH recoveries will reduce the potential for wildfire spread.

...Please see www.spc.noaa.gov/fire for graphic product...

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