Mesoscale Discussion 1421

Issued

Jun 27, 2011, 4:07 PM EDT (20:07 UTC)

Expired

Jun 27, 2011, 5:30 PM EDT

In force

83 min

Issued by

the Storm Prediction Center

The Raleigh/Durham radar (KRAX), 85 km from the middle of the area, began a volume at 20:06 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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611 
ACUS11 KWNS 272007
SWOMCD
SPC MCD 272007 
NCZ000-VAZ000-SCZ000-272130-

MESOSCALE DISCUSSION 1421
NWS STORM PREDICTION CENTER NORMAN OK
0307 PM CDT MON JUN 27 2011

AREAS AFFECTED...MUCH OF NC...NRN SC...FAR SERN VA

CONCERNING...SEVERE THUNDERSTORM WATCH 567...

VALID 272007Z - 272130Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 567
CONTINUES.

FRONTAL CONVERGENCE INVOF THE BAROCLINIC ZONE DRAPED ACROSS FAR SERN
VA AND FAR NRN NC...AND CONVERGENCE ALONG THE SEA BREEZE
BOUNDARY...WILL CONTINUE TO PROVIDE FOCI FOR CLUSTERS OF STRONG TO
SVR THUNDERSTORMS ACROSS WW567 THROUGH THIS AFTERNOON. THE SEA
BREEZE HAS RECENTLY ACCELERATED WELL INLAND IN RESPONSE TO ATTENDANT
CONVECTION AND MERGING COLD POOLS. MEANWHILE...THE SRN FLANK OF THE
COLD POOL ASSOCIATED WITH CONVECTION THAT RECENTLY PASSED THROUGH
THE RALEIGH AREA WILL LIKELY MERGE WITH THE AGGREGATE OUTFLOW / SEA
BREEZE BOUNDARY PROPAGATING NWWD TO FAVOR ADDITIONAL CONVECTIVE
DEVELOPMENT 30 MILES EITHER SIDE OF A LINE FROM 30 NE FAY TO 35 ESE
RWI DURING THE NEXT HOUR. WHERE CONVECTIVE OVERTURNING HAS NOT
OCCURRED...TEMPERATURES IN THE LOWER 90S COMBINED WITH DEWPOINTS IN
THE LOWER TO MIDDLE 70S ARE SUPPORTING MLCAPE VALUES OF 3000 TO 3500
J/KG. THIS WILL FOSTER VIGOROUS UPDRAFTS...ALONG WITH A CONTINUED
THREAT FOR SVR STORMS. WET MICROBURSTS...OWING TO STRONG WATER
LOADING SUPPORTED BY PWAT VALUES IN EXCESS OF 1.65 INCHES PER GPS
TOTAL PRECIPITABLE WATER PRODUCT...COULD PRODUCE DMGG SFC WINDS...AS
HAVE ALREADY BEEN REPORTED WITH STORMS EARLIER THIS AFTERNOON. THIS
WILL PARTICULARLY BE THE CASE WHERE STORM CLUSTERS BECOME BETTER
ORGANIZED IN RESPONSE TO MERGING COLD POOLS. MARGINALLY SEVERE HAIL
WILL ALSO BE OF CONCERN GIVEN THE DEGREE OF INSTABILITY. THE
AFOREMENTIONED PWAT VALUES COULD SUPPORT RAINFALL RATES IN EXCESS OF
1.5 INCHES PER HOUR.

ADDITIONALLY...INTENSE CONVECTION DEVELOPED EARLIER WEST OF WW567
OVER THE SRN APPALACHIANS IN RESPONSE TO OROGRAPHIC EFFECTS
COINCIDENT WITH MODERATE INSTABILITY. WHILE THIS ACTIVITY COULD
BRIEFLY POSE AN ISOLATED SVR THREAT...THIS THREAT WILL LIKELY BE
MITIGATED AS IT IMPINGES ON A MINIMUM IN MLCAPE BETWEEN THE ACTIVITY
AND THE WRN FRINGES OF WW567. AS SUCH...WWD EXPANSION OF WW567 IS
NOT NECESSARY.

..COHEN.. 06/27/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...AKQ...MHX...RAH...ILM...CAE...GSP...

LAT...LON   35908232 35948107 36107928 36457798 36547728 36927681
            36917638 36587593 35937556 35207549 34287716 33897781
            33647871 33717929 33817932 34537964 34698023 34678127
            34558174 34458218 34628267 35278271 35908232

Mesoscale Discussions in North Carolina, 2011Mesoscale Discussions in South Carolina, 2011Mesoscale Discussions in Virginia, 2011Every mesoscale discussion in 2011

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.