March 23rd-25th Severe Weather Thread

[andyhb]

An upper trough is currently digging over the Intermountain West. This feature could become the focus for isolated severe storms tomorrow and then a potentially more widespread threat on Saturday (especially later on) and Sunday across the SE. There remains differences in the evolution of the low level environment, particularly from Saturday on, with the 00z GFS/GGEM/Euro coming in further suppressed with the sfc low/warm front, which would limit the threat further south. Meanwhile, the NAM/UK, suggests the threat expands further northward perhaps towards the TN Valley region as well.

 

DAY 1 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   1252 AM CDT FRI MAR 22 2013      VALID 221200Z - 231200Z      ...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF ERN TX TO THE   LOWER MS VALLEY LATE AFTERNOON/EARLY EVENING...      ...SYNOPSIS...   A PAIR OF AMPLIFIED UPPER-LEVEL TROUGHS WILL CONTINUE TO BE ANCHORED   ACROSS THE NERN AND NWRN CONUS...SHIFTING SLIGHTLY FARTHER EAST INTO   EARLY SAT. AN EMBEDDED SHORTWAVE IMPULSE WILL DIG FROM THE PACIFIC   NW TO THE ERN GREAT BASIN. THIS WILL INDUCE MINOR MID-LEVEL HEIGHT   RISES OVER MOST OF THE GULF COAST STATES. HOWEVER...STRONG MID-LEVEL   WLYS WILL PERSIST ACROSS THE S-CNTRL/SERN CONUS WITH A COUPLE OF   EMBEDDED WEAK SRN STREAM IMPULSES. AT THE SURFACE...CYCLONE OVER N   TX WILL WEAKEN SUBSTANTIALLY THIS MORNING AS IT TRACKS E/SEWD ALONG   A QUASI-STATIONARY FRONT. THIS BOUNDARY SHOULD EXTEND ACROSS PARTS   OF ERN TX INTO NRN LA THIS AFTERNOON.      ...ERN TX TO THE LOWER MS VALLEY...   ELEVATED TSTMS WITH A RISK OF MARGINALLY SEVERE HAIL WILL BE ONGOING   AT 12Z GIVEN STRONG LOW-LEVEL WAA. IN THE WAKE OF THIS REGIME...AN   EML WILL EXPAND EWD FROM THE SRN PLAINS...EFFECTIVELY CAPPING   POTENTIAL FOR SURFACE-BASED TSTMS UNTIL LATE AFTERNOON. ALTHOUGH   LOW-LEVEL SWLYS WILL WEAKEN THROUGH THE DAY...ADVECTION OF MIDDLE   60S SURFACE DEW POINTS FROM THE WRN GULF COAST APPEARS PROBABLE   BENEATH THE CAP. AS STRONGER HEATING OCCURS S OF THE FRONT...A   MODERATELY UNSTABLE AIR MASS SHOULD DEVELOP WITH MLCAPE POTENTIALLY   REACHING 1500-2500 J/KG CENTERED OVER SERN TX INTO CNTRL LA. AMIDST   ELONGATED HODOGRAPHS...ENVIRONMENT WOULD SUPPORT ROTATING UPDRAFTS   CAPABLE OF ALL SEVERE HAZARDS.       HOWEVER...THE SYNOPTIC PATTERN DOES NOT APPEAR PARTICULARLY   FAVORABLE FOR SUSTAINING TSTM DEVELOPMENT DURING THE LATE   AFTERNOON...GIVEN THE AFOREMENTIONED WEAKENING OF THE SURFACE   CYCLONE AND MINOR MID-LEVEL HEIGHT RISES. 00Z CONVECTION-ALLOWING   WRF-NMM GUIDANCE LARGELY CONFIRMS THIS SCENARIO WITH THE LACK OF ANY   SUSTAINABLE DEVELOPMENT. NEVERTHELESS...OPERATIONAL GUIDANCE IS   LARGELY INSISTENT THAT LOW-LEVEL CONVERGENCE ALONG THE W/E-ORIENTED   FRONT WOULD BE SUFFICIENT FOR CONVECTION DURING THE LATE   AFTERNOON/EARLY EVENING. ALTHOUGH CONDITIONAL...THE POTENTIAL THREAT   APPEARS SUFFICIENT TO WARRANT A SLIGHT RISK ATTM.      ...DEEP SOUTH...CNTRL/ERN GULF COAST...   ELEVATED CONVECTION WILL SPREAD E DURING THE PERIOD WITHIN A   PERSISTENT LOW-LEVEL WAA REGIME. A RISK FOR MARGINALLY SEVERE HAIL   MAY EXIST ALONG THE LEADING EDGE OF THE EML EMANATING EWD FROM THE   SRN PLAINS ACROSS THE LOWER MS VALLEY. DESPITE MINOR MID-LEVEL   HEIGHT RISES...MOST GUIDANCE SUGGEST A NOCTURNAL INCREASE IN   CONVECTIVE COVERAGE WILL OCCUR EARLY SAT ALONG THE CNTRL/ERN GULF   COAST. DEEP-LAYER SHEAR WILL BE SUFFICIENT FOR A CONTINUED LOW-END   SEVERE RISK.      ...EDWARDS PLATEAU OF TX...   AS WEAK MID-LEVEL HEIGHT FALLS OVERSPREAD THE REGION IN RESPONSE TO   THE AMPLIFYING NWRN CONUS TROUGH...STRENGTHENING LOW-LEVEL SELYS   SHOULD RESULT IN PRONOUNCED ADVECTION OF WRN GULF COAST MOISTURE   BENEATH A STOUT EML. ALTHOUGH IT IS PLAUSIBLE THAT MUCIN MAY NOT BE   EFFECTIVELY MINIMIZED PRIOR TO 12Z/SAT...WILL MAINTAIN LOW SEVERE   PROBABILITIES GIVEN SOME GUIDANCE INITIATING CONVECTION LATE IN THE   PERIOD. IF THIS OCCURS...VERY STEEP MID-LEVEL LAPSE RATES AND STRONG   EFFECTIVE SHEAR WOULD SUPPORT A RISK FOR ISOLATED LARGE HAIL.      ..GRAMS/LEITMAN.. 03/22/2013

 

DAY 2 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   1256 AM CDT FRI MAR 22 2013      VALID 231200Z - 241200Z      ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL GULF COAST   REGION...      ...SYNOPSIS...   UPPER TROUGHING OVER THE INTERMOUNTAIN REGION AT THE START OF THE   PERIOD IS FORECAST TO DIG ESEWD ACROSS THE CENTRAL AND SRN PLAINS   WITH TIME...APPROACHING THE MID MS VALLEY LATE IN THE PERIOD.        AS THE TROUGH DIGS...A SURFACE LOW INITIALLY OVER THE WRN HALF OF TX   IS FORECAST TO REDEVELOP OVER THE LOWER MS VALLEY DURING THE   EVENING.  AS THIS OCCURS...A COLD FRONT IS FORECAST TO SURGE SEWD   ACROSS THE HIGH PLAINS.  BY THE END OF THE PERIOD...A DEEPENING LOW   IS EXPECTED TO RESIDE OVER THE WRN HALF OF TN...WITH A COLD FRONT   EXTENDING FROM THE TN VALLEY SWWD INTO THE WRN GULF OF MEXICO.       ...CENTRAL GULF COAST REGION...   AS THE SURFACE LOW REDEVELOPING INVOF THE LA VICINITY DURING THE   AFTERNOON EVOLVES AND MOVES NEWD THROUGH THE SECOND HALF OF THE   PERIOD...A WARM FRONT ALSO RETREATING NWD ACROSS THE CENTRAL GULF   COAST STATES AND A COLD FRONT MOVING EWD ACROSS THE LOWER MS VALLEY   SHOULD BOTH SERVE AS FOCI FOR CONVECTIVE DEVELOPMENT.  WITH NWD   ADVECTION GULF MOISTURE INTO THE AREA SUPPORTING MIXED-LAYER CAPE OF   500 TO 1500 J/KG FUELING STORM DEVELOPMENT...STORMS SHOULD BECOME   FAIRLY WIDESPREAD AFTER DARK.        AS THE UPPER TROUGH ADVANCES...INCREASING WSWLY FLOW ALOFT WILL   CONTRIBUTE TO SHEAR SUPPORTIVE OF ORGANIZED/ROTATING STORMS.    ATTM...MODEL DIFFERENCES CAST UNCERTAINTY REGARDING STORM MODE AND   AXES OF MORE FAVORABLE DEVELOPMENT...BUT IT APPEARS THAT SOME   COMBINATION OF LINEAR MODE INVOF THE COLD FRONT AND MORE CELLULAR   CONVECTION INVOF THE RETREATING WARM FRONT WILL BE POSSIBLE.  THUS   -- ALONG WITH HAIL POTENTIAL...LOCALLY DAMAGING WINDS AND ISOLATED   TORNADOES APPEAR POSSIBLE.  DESPITE AFOREMENTIONED   UNCERTAINTIES...IT APPEARS THAT SEVERE POTENTIAL WILL BECOME   WIDESPREAD/SUBSTANTIAL ENOUGH TO WARRANT INCLUSION OF 30% SEVERE   PROBABILITY THIS FORECAST.      ..GOSS.. 03/22/2013

[NavarreDon]

I am headed down to the Western FL Panhandle tonight. Will keep you guys posted on what is going on down there.

[audioguy3107]

As of right now, looks like no dice for anything up here in NE Georgia again due again to early spring wedge.  Its just amazing how relentless these d*&$ things are in spring, but want one in January for a nice winter event......forget it  .  I'm sure this setup will render CAPE values nonexistent here.

 

 

[NGaWxNerd]

I'm going to channel Brick for a minute....NEGa wedge can kiss my grits. Never cold enough for snow yet strong enough to hold back stormy weather. Boring!!!

[SmokeEater]

You guys complaining about the wedge, do realize N GA isn't even in the 5% right? N GA isn't a factor in this event, never was. It's not all about your backyard guys, just saying.

[andyhb]

Both of the deadliest tornadoes in GA history (June 1st, 1902 and April 6th, 1936) have struck Gainesville in NE GA...so it most certainly can happen.

[audioguy3107]

You guys complaining about the wedge, do realize N GA isn't even in the 5% right? N GA isn't a factor in this event, never was. It's not all about your backyard guys, just saying.

 

Not speaking for everyone, but of course I realize that this was never a north Georgia event, it's a little frustration that carries over from a lot of our winter discussions on the SE board.

 

A. whenever we seem to have a risk of IP or an ice storm, it seems that the CADs are never quite strong enough to help us out there, yet when it comes to early spring they arrive with a vengeance to damper any severe weather risk.  I along with a lot of others on here love good thunderstorms and if you do, it's annoying constantly having supercells and QLCS race eastward from Alabama only to hit a brick wall when they reach Fulton county and we don't end up hearing one rumble of thunder.  

 

B.  Once late March and April come around, having it 44 and drizzle with a stiff E wind makes for a fairly miserable day.

 

Hope that explains it in better detail.

[metalicwx366]

Surprisingly the tornado threat increases even more overnight Saturday night. Im on the far end of the 15% area. The fun stays in the FL panhandle.

[Disc]

Hi-res 00Z 4km NAM simulated reflectivity has what looks to be a few discrete storms moving across S and C parts of AL and GA. 4km hasn't shown these on previous runs.

[metalicwx366]

Big storms rolling across the SGA and NFL. Were under a severe thunderstorm warning mainly S of here though.

[SmokeEater]

Severe watch coming for S MS and S AL.

[Disc]

Tornado warning for Clay, Bradford and St.Johns counties in Florida just south of KJAX. Other cells coming ashore along the panhandle look pretty good too.

[NavarreDon]

Hey guys, I am in Navarre,FL (Santa Rosa county) just east of Pensacola. The weather is really starting to fire up down here. It's really humid and the rumbles of thunder are getting more frequent. Rain is intermittent but building. I am really near the coast & the best action should be more inland to the north. I will keep you posted if we get anything significant.

[andyhb]

MESOSCALE DISCUSSION 0307   NWS STORM PREDICTION CENTER NORMAN OK   0501 PM CDT SAT MAR 23 2013      AREAS AFFECTED...NRN LA INTO CNTRL MS      CONCERNING...SEVERE POTENTIAL...WATCH LIKELY       VALID 232201Z - 240000Z      PROBABILITY OF WATCH ISSUANCE...95 PERCENT      SUMMARY...STORMS WILL INCREASE IN COVERAGE AND INTENSITY THROUGH   EVENING WITH LARGE HAIL...DAMAGING WINDS AND A FEW TORNADOES   POSSIBLE.      DISCUSSION...SURFACE ANALYSIS SHOWS A LOW ACROSS NWRN LA...WITH A   SYNOPTIC BOUNDARY EXTENDING NEWD INTO CNTRL MS. S OF THIS FRONT...A   VERY MOIST AND UNSTABLE AIR MASS EXISTS ALONG WITH MIDLEVEL LAPSE   RATES ON THE ORDER OF 7.0-8.0 C/KM.      AS THE UPPER SHORTWAVE TROUGH ADVANCES AND HEIGHT FALLS COMMENCE   AFTER 00Z...SHEAR PROFILES SHOULD STRENGTHEN FURTHER...ESPECIALLY IN   THE LOW LEVELS...CREATING A FAVORABLE ENVIRONMENT FOR SUPERCELLS.   THE MOST LIKELY CORRIDOR FOR DAMAGING WINDS AND TORNADOES WILL BE   ALONG THE FRONT ACROSS CNTRL MS THIS EVENING...AND THEN EXTENDING   NEWD INTO AL LATER TONIGHT.      FOR AREAS WELL N OF THE SURFACE FRONT...HAIL WILL BE LIKELY.      ..JEWELL/KERR.. 03/23/2013

[andyhb]

Tornado watch issued for Central/Southern MS.

 

URGENT - IMMEDIATE BROADCAST REQUESTED   TORNADO WATCH NUMBER 59   NWS STORM PREDICTION CENTER NORMAN OK   520 PM CDT SAT MAR 23 2013      THE NWS STORM PREDICTION CENTER HAS ISSUED A   TORNADO WATCH FOR PORTIONS OF              PARTS OF SOUTHERN AND CENTRAL MISSISSIPPI      EFFECTIVE THIS SATURDAY AFTERNOON AND SUNDAY MORNING FROM 520 PM   UNTIL 100 AM CDT.      TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND   GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE   AREAS.      THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE   MILES NORTH AND SOUTH OF A LINE FROM 55 MILES NORTHWEST OF MC   COMB MISSISSIPPI TO 25 MILES EAST SOUTHEAST OF MERIDIAN   MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE   ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).      REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR   TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS   AND POSSIBLE WARNINGS.      OTHER WATCH INFORMATION...CONTINUE...WW 58...      DISCUSSION...THE ENVIRONMENT IS BECOMING INCREASING CONDUCIVE TO   SUPERCELLS ACROSS THE WATCH AREA THIS EVENING.  AS LOW-LEVEL WIND   FIELDS STRENGTHEN IN RESPONSE TO A DEVELOPING SURFACE LOW ACROSS THE   LOWER MISSISSIPPI VALLEY...STORMS MAY BECOME CAPABLE OF PRODUCING A   COUPLE OF TORNADOES...IN ADDITION TO LARGE HAIL AND LOCALLY DAMAGING   WIND GUSTS.      AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL   SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE   WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO   450. MEAN STORM MOTION VECTOR 25040.         ...KERR

[SouthernNJ]

Pretty dangerous line busting through Yazoo City, they

could be seeing some big hail and winds from it.

[SmokeEater]

JAN: 10 ESE Wilmot [West Carroll Co, LA] trained spotter reports HAIL of ping pong ball size (E1.50 INCH) at 06:30 PM CDT -- windows broken out and siding damaged by hail up to ping pong size hail near the concord community

[Clyde]

Submitted my first storm report for Non-Thunderstorm wind damage. I actually saw this softwood tree snap in 45-50 mph gusts while cleaning up my lawn furniture that had been tossed around by earlier winds. This was east of Orlando. We're under a severe thunderstorm warning now, main show about to begin.

[CandymanColumbusGA]

Tornado warning just west of Orlando. Universal is included in the warning and is delaying the golf tournament. 

[Clyde]

Rotation going north of Bay Hill (golf tourney), but is moving into metro Orlando. No reports locally at this point.

[Clyde]

Reports of some mobile home damage in Windermere. Appears rotation is going to go right over my neighborhood in about 10 minutes.

[SmokeEater]

Report of a barn destroyed north of Orlando, possible tornado.

[calculus1]

Report of a barn destroyed north of Orlando, possible tornado.

 

And the Arnold Palmer Invitational at Bay Hill has been suspended since 2 PM because of the inclement weather.

[Clyde]

AT 246 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO

INDICATE A TORNADO. THIS TORNADO WAS LOCATED NEAR AVALON

PARK...MOVING EAST AT 55 MPH.

I'm in Avalon Park. Sporadic large hail, and there was definitely rotation--ground level winds whipped from west to southeast right in the worst of it. No damage here that I could see.

[SmokeEater]

Wow, Orlando International gusted to 86 mph.

[Clyde]

WESH TV-2 is reporting TV towers down at Bay Hill at the golf tournament. Also reporting minor injuries at an air show in Titusville.