Severe Storms OK & KS 4/14/11. South 4/15/11. EC 4/16/2011

[CrazyC83]

New watch coming out.

[CrazyC83]

Tornado probs are 90/80. High Risk at 1630Z?

SEL0

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 150
NWS STORM PREDICTION CENTER NORMAN OK
1205 PM EDT SAT APR 16 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

CENTRAL AND EASTERN NORTH CAROLINA
CENTRAL AND EASTERN SOUTH CAROLINA
SOUTHERN VIRGINIA
COASTAL WATERS

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1205 PM UNTIL
900 PM EDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE 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 95 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES SOUTH SOUTHEAST OF
CHARLESTON SOUTH CAROLINA TO 60 MILES NORTH NORTHEAST OF SOUTH
HILL VIRGINIA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

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 149...

DISCUSSION...TSTMS WILL CONTINUE TO INTENSIFY TODAY ALONG AND AHEAD
OF COLD FRONT...AND THE S OF WARM FRONT RETREATING NWD THROUGH NC
INTO VA. AMBIENT WARM SECTOR IS MOIST AND BREAKS IN THE CLOUDS WILL
SUPPORT LOCALLY STRONG DIABATIC HEATING WITH MLCAPE VALUES
INCREASING TO 1000-1500 J/KG. THIS INSTABILITY COUPLED WITH
EFFECTIVE BULK SHEAR OF 50-60 KT...EFFECTIVE SRH VALUES OF 300-450+
M2/S2 AND ANTICIPATED DISCRETE STORM MODES SUGGESTS A HIGH
LIKELIHOOD OF LONG-LIVED SUPERCELLS CAPABLE OF SIGNIFICANT
TORNADOES.

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 24040.


...MEAD

[RL3AO]

[CrazyC83]

HIGH RISK at 1630Z for North Carolina

MESOSCALE DISCUSSION 0454
NWS STORM PREDICTION CENTER NORMAN OK
1116 AM CDT SAT APR 16 2011

AREAS AFFECTED...ERN NC

CONCERNING...OUTLOOK UPGRADE

VALID 161616Z - 161715Z

AN UPGRADE TO HIGH RISK FOR THE 1630Z CONVECTIVE OUTLOOK UPDATE IS
FORTHCOMING FOR ERN NC. THE COMBINATION OF VERY STRONG
SHEAR/MODERATE INSTABILITY...INCREASING LOW LEVEL MOISTURE...AND
LARGE SCALE ASCENT ACROSS THE REGION THIS AFTERNOON/EVENING LENDS
CONFIDENCE IN THE FORECAST FOR AN OUTBREAK OF SEVERE STORMS CAPABLE
OF PRODUCING SIGNIFICANT TORNADOES.

..SMITH.. 04/16/2011


ATTN...WFO...AKQ...MHX...RAH...ILM...

LAT...LON 34047921 35927883 36467841 36547738 36417656 35997655
34857678 33877798 33787883 34047921

[psyclone]

i'm sure yesterday's overperformance influenced the pds designation on this new watch. yikes. this looks like a scary day for the low country. i am glad to be below the the fray down here in florida. good luck to everyone up there in the eastern carolina territory and stay safe.

[CrazyC83]

i'm sure yesterday's overperformance influenced the pds designation on this new watch. yikes. this looks like a scary day for the low country. i am glad to be below the the fray down here in florida. good luck to everyone up there in the eastern carolina territory and stay safe.

I agree, yesterday may have spooked them since there should have been a High Risk and at least 2 PDS watches, and they probably realize it now. But what if today busts? They will take even more heat. It is a tough call for sure. They are probably being more defensive today.

[RL3AO]

I'll admit I haven't really looked at parameters but I don't see today being nearly as bad as yesterday.

[CrazyC83]

Last time a HIGH risk was so far north and east: May 31, 1998 in the Northeast (also the only time I have ever been in one)

[CrazyC83]

I'll admit I haven't really looked at parameters but I don't see today being nearly as bad as yesterday.

It is quite ominous in South Carolina right now but hasn't moved northward yet. I think the SPC is just in a mode where they are taking no chances. This might be questionable but everyone will be on edge after yesterday.

[psyclone]

i think you have a valid point crazy but also keep in mind that high risk and pds designations are terms not well known outside of the met/weather geek community. the appropriate wording and timing of warnings is key for the public. look at that tiny cell in horry county. it looks like an innocuous thunderstorm from a reflectivity standpoint but it started to immediately rotate. that, in conjunction with a fast forward motion is awful darn scary...even by tornado alley standards.

[CrazyC83]

SPC AC 161630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT SAT APR 16 2011

VALID 161630Z - 171200Z

...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF ERN NC AND FAR
ERN SC...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF SC...NC AND
VA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE
MID-ATLANTIC...CAROLINAS AND ERN GA...

...TORNADO OUTBREAK EXPECTED THIS AFTERNOON AND EARLY THIS EVENING
ACROSS ERN NC AND FAR ERN SC WHERE A HIGH RISK HAS BEEN ADDED...

...CAROLINAS/VA/WV/MID-ATLANTIC/ERN GA...
A VIGOROUS UPPER-LEVEL TROUGH WILL MOVE INTO THE OH AND TN VALLEYS
TODAY AS A WELL-DEFINED 70 TO 85 KT MID-LEVEL JET ROUNDS THE BASE OF
THE TROUGH AND NOSES INTO THE CAROLINAS. THE JET WILL CREATE STRONG
DEEP LAYER SHEAR PROFILES WHICH WILL BE VERY FAVORABLE FOR SEVERE
STORMS AND TORNADOES THIS AFTERNOON. AT THE SFC A COLD FRONT WILL
MOVE QUICKLY EWD ACROSS THE SRN APPALACHIAN MOUNTAINS. AHEAD OF THE
FRONT...MODERATE DESTABILIZATION WILL LIKELY TAKE PLACE TODAY ALONG
A MOIST AXIS WHERE SFC DEWPOINTS WILL BE IN THE MID TO UPPER 60S F.
STRONG THUNDERSTORMS SHOULD INITIATE ON THE WRN EDGE OF THE MOIST
AXIS IN THE WRN CAROLINAS AND RAPIDLY INCREASE IN COVERAGE EARLY
THIS AFTERNOON. SEVERE STORMS ARE FORECAST TO MOVE INTO THE
CNTRL/ERN CAROLINAS AND ACROSS CNTRL/ERN VA LATE THIS AFTERNOON INTO
EARLY THIS EVENING.

FORECAST SOUNDINGS ALONG THE MOIST AXIS IN THE ERN CAROLINAS AT 21Z
SHOW 0-6 KM SHEAR VALUES AROUND 60 KT WITH MLCAPE OF 1500 TO 2000
J/KG. IN ADDITION...LOW-LEVEL SHEAR WILL BE STRONG SUGGESTING THE
THERMODYNAMIC AND SHEAR ENVIRONMENT WILL BE VERY FAVORABLE FOR
SUPERCELLS AND TORNADOES IN THE MODERATE AND HIGH RISK AREAS. 0 TO 3
KM STORM RELATIVE HELICITIES IN THE 450 TO 550 M2/S2 RANGE WILL ALSO
BE FAVORABLE FOR STRONG TORNADOES WITH THE MORE DOMINANT DISCRETE
SUPERCELLS. THE GREATEST THREAT FOR STRONG TORNADOES SHOULD EXIST
FROM RALEIGH NC SSWWD TO NEAR FLORENCE SC AND EAST OF THAT LINE
ABOUT 100 STATUTE MILES. THIS AREA WILL BE LOCATED WHERE THE
CROSSOVER OF THE LOW AND MID-LEVEL JET IS MAXIMIZED. A LONG-TRACK
TORNADO OR TWO IS EXPECTED TO OCCUR ACROSS THE HIGH RISK AREA IN ERN
NC AND FAR ERN SC. AS STORM COVERAGE INCREASES THIS AFTERNOON AND A
LINE OF STORMS ORGANIZES...A WIND DAMAGE THREAT WILL ALSO DEVELOP
FROM THE MID-ATLANTIC SWD ACROSS THE CAROLINAS INTO ERN GA. 50 KT OF
FLOW JUST ABOVE THE SFC AND A FAST EWD MOTION OF THE LINE SHOULD
RESULT IN A WIDESPREAD WIND DAMAGE THREAT WITH VERY STRONG WIND
GUSTS POSSIBLE WITH THE MORE INTENSE BOWING LINE-SEGMENTS ACROSS THE
MODERATE AND HIGH RISK AREAS. SUPERCELLS AND THE MORE INTENSE CELLS
WITHIN THE LINE SHOULD BE CAPABLE OF PRODUCING LARGE HAIL AS WELL.
THE LINE IS FORECAST TO MOVE ACROSS THE OUTER BANKS OF NC THIS
EVENING WITH THE SEVERE THREAT ENDING FROM WEST TO EAST ACROSS THE
REGION.

WHILE SHEAR CONDITIONS WILL BE FAVORABLE FOR TORNADOES AS FAR NORTH
AS NRN VA AND MD...THE THREAT WILL BE MORE CONDITIONAL. ACROSS ERN
GA...THIS AREA WILL BE SOUTH OF THE MID-LEVEL JET AND REMOVED FROM
THE STRONG LARGE-SCALE ASCENT SUGGESTING THE SEVERE THREAT WILL
REMAIN MORE ISOLATED ACROSS ERN GA.

..BROYLES/SMITH.. 04/16/2011

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1635Z (12:35PM), RELOAD THIS PAGE TO UPDATE THE TIME

[RL3AO]

TDWR stations only have BV not SRV. Thats really quite the couplet.

[CrazyC83]

TDWR stations only have BV not SRV. Thats really quite the couplet.

It looked like there was a debris ball there at one point too. Pretty compact but intense it looks like.

[RL3AO]

That storm is crossing WFO borders. Raleigh had to issue a TOR. The western most part of that county now pretty much has no warning lead time.

[CrazyC83]

That storm is crossing WFO borders. Raleigh had to issue a TOR. The western most part of that county now pretty much has no warning lead time.

Those are always tough to manage, they need to co-ordinate between each other. During severe weather outbreaks, IMO, multiple offices (in this case Raleigh, Greenville-Spartanburg, Columbia, Charleston, Wilmington, Morehead City-Newport, Blacksburg and Wakefield, possibly Baltimore-Washington later) should always be telecommunicating and warnings should be allowed to cross borders.

In the report after the Super Tuesday outbreak, there were complaints of such miscommunication between Nashville and Louisville that ended up causing a deadly tornado with almost no lead time.

[CrazyC83]

Eastern North Carolina, IMO, is the best chasing country east of the Appalachians as it is really flat there and mostly rural. So we might get good chasing and early warning, even if they are wrapped in rain.

[RL3AO]

I remember a large tornado on the ground that moved right along the Norman and Fort Worth WFO border for a good 30 minutes. Weirdest looking warning polygons I've seen.

[CrazyC83]

I remember a large tornado on the ground that moved right along the Norman and Fort Worth WFO border for a good 30 minutes. Weirdest looking warning polygons I've seen.

The only thing worse is if a warning polygon has to hug an international border. That requires co-ordination between the WFOs and Canadian or (much less often) Mexican agencies since tornadoes do not respect boundaries, not even international.

[CrazyC83]

Last time a part of North Carolina was in a High Risk: March 28, 1984. That day, 57 people died. AFAIK, that area has been under only two PDS watches in the last few years: December 2, 2009 (busted) and March 15, 2008 (major outbreak especially in SC).

[RL3AO]

That TOR cell is about to move into a radar gap. Can't see anything under 10000 feet.