Mesoscale Discussion 1749

Issued

Aug 13, 2012, 1:45 AM CDT (06:45 UTC)

Expired

Aug 13, 2012, 3:45 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

The Little Rock radar (KLZK), 98 km from the middle of the area, began a volume at 06:48 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

461 
ACUS11 KWNS 130645
SWOMCD
SPC MCD 130645 
MOZ000-ARZ000-OKZ000-130845-

MESOSCALE DISCUSSION 1749
NWS STORM PREDICTION CENTER NORMAN OK
0145 AM CDT MON AUG 13 2012

AREAS AFFECTED...PORTIONS ERN OK...SRN MO...AR.

CONCERNING...SEVERE THUNDERSTORM WATCH 575...

VALID 130645Z - 130845Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 575
CONTINUES.

SUMMARY...POTENTIAL CONTINUES FOR ISOLATED TO WIDELY SCATTERED LARGE
HAIL WITH TWO MAIN CLUSTERS OF CONVECTION OVER WW AREA.  THIS THREAT
MAY CONTINUE SPATIALLY E OF WW AND ON VERY ISOLATED/MRGL BASIS
BEYOND SCHEDULED WW EXPIRATION...ALONG WITH ISOLATED DAMAGING GUSTS
FROM SRN CLUSTER OVER CENTRAL AR.  WW MAY BE EXTENDED LOCALLY EWD
OVER PORTIONS CENTRAL AR TO STAY AHEAD OF CONVECTION APCHG THAT
AREA...AS TRENDS WARRANT.  HOWEVER...ORGANIZED SVR POTENTIAL SHOULD
UNDERGO GRADUAL LESSENING AFTER ABOUT 09Z.

DISCUSSION...SFC MESOANALYSIS SHOWS PRIMARY CYCLONE OVER CENTRAL MO
WITH COLD FRONT SWWD ACROSS SWRN MO...E-CENTRAL/S-CENTRAL OK AND
PERMIAN BASIN REGION OF W TX.  COLD FRONT SHOULD CONTINUE MOVING
EWD/SEWD OVER NWRN AR...SERN OK AND PORTIONS N-CENTRAL TX BY 12Z. 
AHEAD OF THIS FRONT...LLJ WILL VEER AND INCREASE SLIGHTLY TO 30-35
KT RANGE FROM SERN OK ACROSS CENTRAL AR.  ASSOCIATED MOISTURE
TRANSPORT ABOVE SFC MAY SUPPORT CONTINUATION OF TSTMS NOW OVER
W-CENTRAL AR AS THEY MOVE ESEWD ACROSS CENTRAL AR...WHERE MODIFIED
RAOB AND MODEL SOUNDINGS SUGGEST SFC MOIST AXIS AND RELATED 70S F
SFC DEW POINTS SUPPORT POCKET OF 1000-1500 J/KG MLCAPE.  SUBSTANTIAL
DECREASE IN MLCAPE AND INCREASE IN CINH IS EVIDENT FARTHER E ACROSS
AR INTO WRN TN...E OF SFC WARM FRONT ANALYZED AT 6Z FROM POPE COUNTY
AR SEWD TO NEAR GLH-JAN LINE.  CONVECTIVE POTENTIAL WILL OUTPACE
NEWD MOVEMENT OF WARM FRONT OVER ERN AR.  ACTIVITY OVER OZARKS NEAR
MO/AR BORDER IS N OF WARM FRONT AND APPEARS ELEVATED...WITH
ADDITIONAL TSTMS PSBL NE OF WARM FRONT THROUGH REMAINDER MORNING.

MOISTURE CHANNEL IMAGERY INDICATES STG DRYING AND LARGE-SCALE
SUBSIDENCE ALOFT...MOVING SEWD ACROSS ERN OK AND OVER EXTREME WRN
AR.  WHILE ASSOCIATED DVM WILL NOT PRECLUDE TSTM FORMATION
COMPLETELY...IT INDICATES LESS-FAVORABLE ENVIRONMENT WITH WWD EXTENT
AND DECREASING PROBABILITY OF SVR OVER ERN OK.  OK PORTIONS OF THIS
WW HAVE BEEN CLEARED.

..EDWARDS.. 08/13/2012

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

ATTN...WFO...PAH...MEG...LZK...SGF...TSA...

LAT...LON   34739537 36399460 36859291 36909112 36249115 33979121
            33839200 34779425 34739537

Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Oklahoma, 2012Mesoscale Discussions in Missouri, 2012Every mesoscale discussion in 2012

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.