Blue Flower

Outlook (Main)

Storm Prediction Center
SPC Forecast Products
  1. No watches are valid as of Fri Apr 16 08:36:02 UTC 2021.
  2. MD 0392 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN LOUISIANA
    MD 0392 Image
    
    Mesoscale Discussion 0392
    NWS Storm Prediction Center Norman OK
    0330 AM CDT Fri Apr 16 2021
    
    Areas affected...Southern Louisiana
    
    Concerning...Severe potential...Watch unlikely 
    
    Valid 160830Z - 161100Z
    
    Probability of Watch Issuance...20 percent
    
    SUMMARY...An isolated large hail and strong wind gusts potential
    will exist early this morning across parts of southern Louisiana.
    The threat is expected to remain localized and weather watch
    issuance appears unlikely.
    
    DISCUSSION...Over the last few hours, a small cluster of strong
    thunderstorms has developed in the Sabine River Valley. This cluster
    is being supported by large-scale ascent ahead of a shortwave trough
    currently moving through the southern Plains. A short line segment
    at the western end of the cluster appears to to be an organized
    supercell but elevated in nature. This storm will continue to move
    eastward along a gradient of instability, with the RAP analyzing
    MUCAPE in the 500 to 1000 J/kg range. This combined with about 70 kt
    of westerly flow in the mid-levels will support an isolated severe
    threat over the next few hours. Large hail and strong wind gusts
    will be possible. Storm coverage is expected to remain relatively
    isolated. For this reason, weather watch issuance is not expected.
    
    ..Broyles/Grams.. 04/16/2021
    
    ...Please see www.spc.noaa.gov for graphic product...
    
    ATTN...WFO...LIX...LCH...
    
    LAT...LON   31089330 31049361 30879385 30719395 30539401 30239390
                30159374 30019327 29889279 29799209 29799163 29989143
                30229136 30479139 30709166 30969231 31069294 31089330 
    
    
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  3. SPC 1200Z Day 1 Outlook
    Day 1 Outlook Image
    Day 1 Convective Outlook  
    NWS Storm Prediction Center Norman OK
    1253 AM CDT Fri Apr 16 2021
    
    Valid 161200Z - 171200Z
    
    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
    TEXAS ALONG THE GULF COAST TO NORTHERN FLORIDA AND IN PORTIONS SOUTH
    TEXAS....
    
    ...SUMMARY...
    Isolated strong to severe storms capable of hail and gusty winds are
    possible across parts of eastern Texas along the Gulf Coast and into
    north Florida today. An isolated strong to severe storm capable of
    large hail may be possible along the Rio Grande in the South Texas
    late in the period.
    
    ...Synopsis...
    A mid-level shortwave trough will slowly move through the central
    Plains today with an moderately strong mid-level jet overspreading
    much of Texas into the Gulf States. At the surface, a cold front is
    forecast to be in the Texas Panhandle at 12Z Friday and quickly
    accelerate southward across the entire state of Texas to near
    Brownsville by 12Z Saturday. 
    
    ...Eastern Texas into Louisiana and southwest Mississippi...
    Ongoing convection is expected across much of Texas and southern
    Oklahoma at the beginning of the period as a result of increasing
    isentropic ascent resulting from the strengthening low-level jet.
    These morning storms are expected to move southeastward along the
    instability gradient into east Texas and Louisiana during the
    afternoon. Some additional development is possible in a warm air
    advection regime across south and central Louisiana this
    afternoon/evening. However, there is still some uncertainty
    regarding the strength of the low-level jet and therefore, the
    coverage of storms. Regardless of coverage, storms in the area will
    likely be elevated with some supercell structures possible given
    very strong 70+ kts of effective shear. These better organized
    supercell structures will likely pose the primary threat for large
    hail, however the limited instability will likely preclude more than
    an isolated threat. 
    
    Farther west across Texas, some surface based instability is
    expected to develop ahead of the cold front. This instability
    combined with lift from the surface front may be sufficient for a
    few storms during the afternoon/early evening. However, most of the
    forcing is expected to be across Louisiana and Arkansas by late
    afternoon with height rises expected across central and south Texas
    after 21Z. In addition, the rapid southward movement of the cold
    front will likely limit parcel residence time and may also be a
    negative factor for deep convection along the front. Any storms
    which can develop would pose an isolated large hail and damaging
    wind threat. 
    
    ...South Texas near the Rio Grande...
    Forecast soundings show much of this region capped through the
    evening hours, but height falls from an approaching shortwave after
    06Z will increase the chances for storms late in the period. Storms
    will have a greater probability across the border in Mexico with the
    assistance of upslope flow behind the front. Forecast soundings show
    elevated instability for several hours post-frontal which would
    support a brief supercell or two late in the period with large hail
    as the primary threat. 
    
    ...Southern Alabama and north Florida...
    A weak mid-level shortwave trough over Louisiana early this morning
    will move east-southeastward through the morning hours. As this
    impulse approaches a stalled surface front across north-central
    Florida during the morning hours, convection is expected to develop
    and strengthen. Temperatures are expected to warm into the mid 70s
    with dewpoints in the mid to upper 60s south of this warm front
    yielding around 1000 to 1500 J/kg MLCAPE. Strong mid-level flow in
    excess of 50 knots will provide ample effective shear (45+ kts) or
    storm organization and the potential for supercell structures. Large
    hail and damaging winds will be the primary threat with this
    activity.
    
    A strengthening low-level jet is expected to persist across the
    northern Gulf Friday night with a large reservoir of 1000+ J/kg
    MUCAPE available to feed mostly elevated storm activity along the
    coast. Strong shear may help maintain storm longevity within these
    clusters with occasional strong to isolated severe storms. The
    unstable upstream airmass will likely maintain this marginal severe
    threat through 12Z Saturday into the northern Florida Peninsula.
    
    ..Bentley/Dial.. 04/16/2021
    
    
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  4. SPC 0600Z Day 2 Outlook
    Day 2 Outlook Image
    Day 2 Convective Outlook  
    NWS Storm Prediction Center Norman OK
    1252 AM CDT Fri Apr 16 2021
    
    Valid 171200Z - 181200Z
    
    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE CENTRAL GULF COAST INTO SOUTHERN GEORGIA...AND DEEP SOUTH
    TEXAS...
    
    ...SUMMARY...
    Isolated strong to severe storms appear possible Saturday across
    parts of the central Gulf Coast into southern Georgia. A few
    instances of large hail may also occur Saturday morning across deep
    south Texas.
    
    ...Synopsis...
    A 60-80 kt mid-level westerly jet is forecast to be present over
    much of the Southeast Saturday. A low-amplitude shortwave trough
    will advance eastward from the mid MS Valley to the Mid-Atlantic
    through the day. A 30-40 kt west-southwesterly low-level jet should
    be focused over the vicinity of northern FL and southern GA through
    at least Saturday afternoon. At the surface, a cold front will move
    off the TX/LA Gulf Coast, while a weak low develops northeastward
    from coastal LA/MS/AL to northern FL and southern GA along a warm
    front. This front is not expected to make much northward progress
    through the day across southern GA.
    
    ...Southeast...
    Convection will likely be ongoing Saturday morning across the
    central Gulf Coast with support from a low-level jet. Limited
    convergence along the warm front and mid-level flow largely parallel
    to this boundary creates a fair amount of uncertainty regarding how
    much convection will develop through the day. Most guidance suggests
    that overall storm coverage may remain quite isolated, before
    possibly increasing some by late Saturday afternoon. Regardless, any
    storms that can form along/south of the warm front from coastal AL
    across the FL Panhandle and into southern GA may pose an isolated
    severe threat. Deep-layer shear appears strong enough to support
    supercells, but low-level shear may gradually decrease through the
    afternoon as the low-level jet veers to westerly and shifts towards
    the Atlantic Coast. Occasional strong to damaging winds appear
    possible with any surface-based convection, and a brief tornado may
    also occur near the warm front. Mid-level lapse rates should be
    relatively modest across this region, but isolated instances of
    large hail could also occur Saturday afternoon/evening across the
    warm sector as instability becomes maximized.
    
    ...Deep South Texas...
    A cold front will quickly progress southward across deep south TX
    Saturday morning. Low-level upslope flow over the mountains of
    adjacent northern Mexico may encourage a couple of elevated
    supercells to form and cross into this region around the beginning
    of the Day 2 period. Even though boundary-layer instability will
    quickly decrease behind the front, enough low-level moisture and
    modestly steepened mid-level lapse rates should still support around
    1000-1500 J/kg of MUCAPE. This instability coupled with strong shear
    aloft may foster isolated large hail with any supercell that can
    persist for a few hours. Storms should weaken by mid morning as the
    elevated instability diminishes.
    
    ..Gleason.. 04/16/2021
    
    
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  5. SPC 0730Z Day 3 Outlook
    Day 3 Outlook Image
    Day 3 Convective Outlook  
    NWS Storm Prediction Center Norman OK
    0220 AM CDT Fri Apr 16 2021
    
    Valid 181200Z - 191200Z
    
    ...NO SEVERE THUNDERSTORM AREAS FORECAST...
    
    ...SUMMARY...
    Organized severe thunderstorms appear unlikely across the contiguous
    United States on Sunday.
    
    ...Synopsis and Discussion...
    A belt of strong mid-level westerly flow should be maintained across
    much of the lower MS Valley and Southeast on Sunday. At the surface,
    high pressure should dominate much of the CONUS. A cold front should
    stall and become nearly stationary across the northern FL Peninsula
    by Sunday afternoon. With low/mid-level flow largely parallel to the
    front, convergence is forecast to remain very weak. Accordingly,
    convective development along this boundary appears quite uncertain
    on Sunday. Even if storms form across the northern FL Peninsula,
    they will probably remain elevated. At this point, the potential for
    organized severe storms along/south of the front across the FL
    Peninsula appears unlikely given poor low-level convergence and
    nebulous large-scale ascent.
    
    Elsewhere, isolated thunderstorms appear possible through the day
    across parts of the mid MS Valley in association with a shortwave
    trough, and over portions of the southern Rockies and vicinity as
    large-scale ascent with a separate upper trough/low overspreads this
    region. Very limited instability is expected to preclude a severe
    threat for both areas.
    
    ..Gleason.. 04/16/2021
    
    
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