Heavy rain/Storm event 5/15/14

[Solak]

Thought today's system deserved a thread of it's own. The widespread 1"-2" inches is trending to be more significant than that. There's already been one Tor. warning early this morning.

752 AM EDT THU MAY 15 2014 AREAS AFFECTED...CENTRAL/SOUTHERN SC...WESTCENTRAL NC  CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  VALID 151136Z - 151736Z SUMMARY...SOUTH TO NORTH BAND OF SLOW MOVING THUNDERSTORMS LIKELYTO AFFECT PORTIONS OF THE SOUTH CAROLINA COAST NORTHWARD INTO WESTCENTRAL NORTH CAROLINA WITH RAINFALL RATES OF 2 INCHES OR MORE PERHOUR.  SOME SHORT TERM AMOUNTS OF UP TO 5 INCHES IN SEVERAL HOURSMAY OCCUR INCREASING THREAT OF FLASH FLOODING.DISCUSSION...LATEST SATL/RADAR IMAGERY SHOWS SEVERAL N/S LINESEGMENTS OF VERY HEAVY CONVECTIVE RAINS ENHANCING AHEAD OF A HIGHLEVEL IMPULSE LIFTING NWD ACRS EASTERN GA THAT HAVE BECOME A BITMORE CONSOLIDATED OVER THE PAST HOUR OR TWO.  AT THE SAMETIME..ANOTHER AREA OF ENHANCED CONVECTION FORMING IN A N/S BANDWITHIN AN AREA OF GREATER THAN 2 INCH PWS OFF THE SOUTHEAST COASTWAS LIFTING SLOWLY NWD TOWARD THE SC COAST.  OVER THE NEXT SEVERALHOURS..EXPECT POTNL MERGER OF THE OFFSHORE BAND WORKING NWD TOWARDTHE COAST WITH THE SLOWLY EWD ACTIVITY OVER CNTL SC RESULTING INENHANCED RAINFALL RATES OVER THE OUTLOOK AREA.  HIGH RES GUIDANCE FROM 00Z WAS A LITTLE SLOW WITH THE EWD ADVANCEOF ACTIVITY THIS MORNING..THOUGH DOES SUGGEST SOME LOCALIZEDAMOUNTS IN EXCESS OF 5 INCHES OVER THE OUTLOOK AREA WHICH SEEMSLIKELY GIVEN TRAINING POTNL SET UP WITH DEEP LAYERED SOUTHERLYFLOW. SULLIVAN

[Solak]

Snip from the latest SPC

 ...VA/CAROLINAS...   ONE AREA THAT APPEARS TO HAVE A MORE FOCUSED RISK OF SEVERE STORMS   IS OVER VA AND THE CAROLINAS THIS AFTERNOON AND EVENING.  LOW LEVEL   CYCLOGENESIS IS FORECAST TO BEGIN LATER THIS MORNING OVER PARTS OF   GA AND THE WESTERN CAROLINAS.  AS THIS OCCURS...STRENGTHENING   SOUTHERLY LOW LEVEL WINDS WILL ENLARGE THE HODOGRAPHS AND ENHANCE   WARM ADVECTION/LIFT.  INSTABILITY WILL BE A LIMITING FACTOR DUE TO   EXTENSIVE CLOUDS/PRECIPITATION.  HOWEVER...WITH DEWPOINTS IN THE   MID/UPPER 60S...EVEN MODEST HEATING COULD BE SUFFICIENT FOR A FEW   STRONG TO SEVERE STORMS.  EMBEDDED SUPERCELL STRUCTURES CAPABLE OF   DAMAGING WINDS AND/OR ISOLATED TORNADOES APPEAR TO BE THE MAIN RISK.   DURING THE EVENING...IT APPEARS POSSIBLE THAT CONVECTION WILL   ORGANIZE UPSCALE WITH A QLCS TRACKING EASTWARD ACROSS PARTS OF   VA/NC.  AGAIN...INSTABILITY AND UNCERTAINTY REGARDING BOUNDARY LAYER   LAPSE RATES WILL BE THE LIMITING FACTOR FOR SEVERE STORMS...AND IS   THE REASON FOR NOT EXTENDING THE SLIGHT RISK FARTHER EAST. THIS AREA   WILL NEED FURTHER EVALUATION IN LATER UPDATES.

[Hvward]

The cell moving north towards the Winston-Salem area currently over Mocksville is the same part of the line that was warned over Charlotte.  Still showing some rotation as of late, wouldn't be surprised to see that tighten up again with helicity values above 150 in that area.

[metalicwx366]

71 and light rain. NWS put us under a flood watch for an additional 2-4 inches of rain today.

2.21 so far with the event.

[Disc]

 

MESOSCALE DISCUSSION 0607
   NWS STORM PREDICTION CENTER NORMAN OK
   0729 AM CDT THU MAY 15 2014

   AREAS AFFECTED...SC INTO NC

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

   VALID 151229Z - 151430Z

   PROBABILITY OF WATCH ISSUANCE...60 PERCENT

   SUMMARY...STORMS ARE EXPECTED TO GRADUALLY INCREASE IN COVERAGE THIS
   MORNING...AND A TORNADO WATCH COULD BE REQUIRED BY 14-15Z.

   DISCUSSION...A SLOW-MOVING LINE OF THUNDERSTORMS ASSOCIATED WITH A
   LEADING SHORTWAVE FEATURE WILL CONTINUE TO AFFECT CNTRL
   SC...NC...AND VA THIS MORNING. SOME OF THESE CELLS HAVE SHOWN SIGNS
   OF WEAK ROTATION...BUT NONE HAVE BEEN LONG LIVED YET DUE TO WEAK
   FORCING.

   AHEAD OF THE LINE...A VERY MOIST AIR MASS CONTINUES TO SPREAD NWD
   WITH DEWPOINTS INTO THE LOWER 70S F. THE 12Z CHS SOUNDING INDICATED
   AROUND 1500 J/KG MLCAPE AND NO INHIBITION....WHILE FARTHER N...THE
   RNK SOUNDING SHOWED A FAVORABLE SUPERCELL/TORNADO HODOGRAPH
   CONDITIONAL ON INSTABILITY.

   THE SLOW UPPER TROUGH MOVEMENT WILL RESULT IN MOIST SELY SURFACE
   WINDS ACROSS THE REGION. AS POCKETS OF HEATING OCCUR ALONG WITH SOME
   MOISTURE ADVECTION...THERE SHOULD BE A CORRESPONDING THREAT OF
   TORNADOES....BOTH WITH BROKEN CELLS WITHIN THE LEADING LINE...AND
   WITH NEW ACTIVITY THAT FORMS AHEAD. WHILE CONDITIONS MAY NOT FAVOR
   PARTICULARLY STRONG TORNADOES...SEVERAL TORNADOES WILL BE POSSIBLE
   TODAY...MOST LIKELY FOCUSED IN A NARROW N-S ZONE FROM ERN SC INTO
   CNTRL NC AND VA.

   ..JEWELL/CORFIDI.. 05/15/2014
 

[Brick Tamland]

Came here to post that from the SPC, but looks like I was beat to the punch. Looks like we could have an active day in central NC.

[Brick Tamland]

Strong wording with the several tornadoes possible.

[WxBlue]

10% area today? Interesting...

 

 

 

[Solak]

Slight risk area considerably larger now.

 

http://www.spc.noaa.gov/products/outlook/archive/2014/day1otlk_20140515_1300.html

 

 

[griteater]

1.30 inches of rain at Charlotte airport from 6-9 AM

[metalicwx366]

Looks like a meso-low has formed to the S of here. Can clearly see the spin on radar.

[Brick Tamland]

Overcaste here in north Raleigh. Things seems quiet so far.

[Disc]

0.64" in less than an hour.

[nrgjeff]

Interesting 10% TOR probs. Believe they are looking at the lowest levels where excellent turning is noted from surface up to 700 mb. Surface winds are quite backed too. Challenges include other convection and unidirectional flow farther up (500/200 mb). However that flow is reasonably strong. Don't expect any right moving beasts today, but small short-lived spin ups are possible. Finally, last couple HRRR runs seem to diminish the sups in front of the line, which is bearish tornadoes. Tough forecast but the 10% is not unreasonable given wind fields at/below 700 mb.

[yotaman]

Impressive line of storm over central NC this morning. Looks like a whole bunch of people are gonna get a good bit of rain out of this system.

[Hvward]

Cells in and around the Sanford/Broadway area beginning to show signs of rotation on velocity. 

[Cold Rain]

Watch up:

 

 

[Brick Tamland]

Severe thunderstorm up instead of a tornado watch.

[Wow]

1.16" in the bucket this morning.  Really warming up down east ahead of the line.  Watch out!

[Brick Tamland]

SEVERE THUNDERSTORM WATCH 157 IS IN EFFECT UNTIL 800 PM EDT
FOR THE FOLLOWING LOCATIONS

NCC001-013-015-017-019-031-033-037-047-049-051-061-063-065-069-
077-079-083-085-091-093-101-103-105-107-117-125-127-129-131-133-
135-137-141-145-147-155-163-165-181-183-185-191-195-160000-
/O.NEW.KWNS.SV.A.0157.140515T1555Z-140516T0000Z/

NC
.    NORTH CAROLINA COUNTIES INCLUDED ARE

ALAMANCE             BEAUFORT            BERTIE
BLADEN               BRUNSWICK           CARTERET
CASWELL              CHATHAM             COLUMBUS
CRAVEN               CUMBERLAND          DUPLIN
DURHAM               EDGECOMBE           FRANKLIN
GRANVILLE            GREENE              HALIFAX
HARNETT              HERTFORD            HOKE
JOHNSTON             JONES               LEE
LENOIR               MARTIN              MOORE
NASH                 NEW HANOVER         NORTHAMPTON
ONSLOW               ORANGE              PAMLICO
PENDER               PERSON              PITT
ROBESON              SAMPSON             SCOTLAND
VANCE                WAKE                WARREN
WAYNE                WILSON
 

[Solak]

Slight risk has shifted East.

  ...MID-ATLANTIC STATES INTO CAROLINAS TODAY INTO TONIGHT...   12Z REGIONAL SOUNDINGS SHOW THE PRESENCE OF A VERY MOIST AIR MASS   AHEAD OF THE ONGOING STORMS...CHARACTERIZED BY BOUNDARY LAYER   DEWPOINTS IN THE MID 60S TO LOWER 70S AND LOWEST 100-MB MEAN-MIXING   RATIOS OF 12-15 G/KG. AND WHILE MIDLEVEL LAPSE RATES WILL REMAIN   WEAK...A CORRIDOR OF STRONGER HEATING FROM ERN NC NWD INTO THE   DELMARVA WILL BOOST AFTERNOON MLCAPE VALUES TO 1000-2000 J/KG.   DCVA/HEIGHT FALLS ASSOCIATED WITH THE ABOVE-MENTIONED VORTICITY   MAXIMUM LIFTING NEWD FROM THE PARENT TROUGH BASE WILL GRADUALLY   OVERSPREAD THE WARM SECTOR TODAY...SUPPORTING THE INTENSIFICATION OF   THE PRE-FRONTAL LEADING-LINE....TRAILING-STRATIFORM QLCS OVER VA   INTO THE CAROLINAS. ADDITIONAL STORMS ARE LIKELY TO FORM AHEAD OF   THIS CONVECTIVE SYSTEM...ESPECIALLY AS LOW-LEVEL CONVERGENCE AND WAA   ARE ENHANCED AHEAD OF THE SECONDARY SURFACE LOW. DAMAGING WIND GUSTS   AND PERHAPS A FEW TORNADOES WILL BE THE PRIMARY HAZARDS WITH THESE   STORMS.       THE ISALLOBARIC RESPONSE TO THE SECONDARY SURFACE LOW WILL RESULT IN   BACKING OF NEAR-GROUND WINDS WITH RESULTANT LARGER LOW-LEVEL   HODOGRAPHS AHEAD OF THE CYCLONE TRACK. HOWEVER...IT APPEARS THAT   GREATER TORNADO POTENTIAL WILL BE LIMITED BY CONSIDERABLE CONVECTIVE   OVERTURNING ALREADY OCCURRING ALONG THE SAVANNAH RIVER VALLEY INTO   CNTRL/ERN SC.   AT LEAST AN ISOLATED TORNADO/DAMAGING WIND THREAT MAY PERSIST INTO   THE OVERNIGHT HOURS AHEAD OF THE SYNOPTIC COLD FRONT AS IT   PROGRESSES EWD THROUGH THE PIEDMONT INTO COASTAL PLAIN. LOW-LEVEL   SHEAR WILL BE NOTABLY STRONGER THAN THAT ANTICIPATED THIS AFTERNOON   OWING TO THE PRESENCE OF A 50+ KT SLY LLJ. HOWEVER...UNCERTAINTY   EXISTS WITH REGARD TO HOW UNSTABLE THE AIR MASS WILL BE OWING TO THE   TIME OF DAY AND EFFECTS OF ANTECEDENT TSTMS.

[downeastnc]

Really trashy out in front of the line, need more discrete cells to have a real chance at anything outside a QLCS spinup IMO......might see a handful of wind damage reports if any of the line segments can bow out or we get a curly cue type vort on the top or tail end of a line segment. Had a lot of sun out this morning was fishing till around 10:30 and got a bit of sun temps 85 DP in the mid 60's so we will see but if a line segment doesn't form soon we are in for a lot of trashy showers here in central eastern NC.

[Brick Tamland]

[Solak]

We made it to 81/70 at KJNX before the clouds thickened. Had a good amount of sun this morning, and it got pretty muggy out. Looks like the tornado threat could be diminished, as alluded to in the discussion above..

IT APPEARS THAT   GREATER TORNADO POTENTIAL WILL BE LIMITED BY CONSIDERABLE CONVECTIVE   OVERTURNING ALREADY OCCURRING ALONG THE SAVANNAH RIVER VALLEY INTO   CNTRL/ERN SC.

[downeastnc]

Couple little areas of rotation in the line in the Triangle nothing to get worked up over but the one near Durham is pretty decent just broad....

[downeastnc]

The cell between Cary and RDU is kinda nasty showing a broad couplet and a more classic supercell look.....might do something if it can tighten up

[lj0109]

Managed to snap this just a few minutes ago as this cell traveled north across US 378 in Eastern Sumter County here in SC.  Caught my eye for a frame or two before quickly broadening out 

[downeastnc]

That couplet in north Raleigh looking better could be trouble.......Durham one also trying to tighten up

[downeastnc]

Nothing great but I bet there is a nice low hanging cloud with this area

 

[lj0109]

Another area of broad rotation worth monitoring on the cell now 7M SE Sumter SC on the Sumter/Clarendon County line....following nearly the same path as the previous cell.