[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 271921
SWOMCD
SPC MCD 271920
ALZ000-TNZ000-272045-

MESOSCALE DISCUSSION 2165
NWS STORM PREDICTION CENTER NORMAN OK
0220 PM CDT FRI OCT 27 2006

AREAS AFFECTED...PORTIONS NWRN/N-CENTRAL AL...SRN MID TN.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 271920Z - 272045Z

SOME SVR POTENTIAL MAY DEVELOP THROUGH MID-LATE AFTERNOON...MAINLY
OVER PORTIONS NRN AL.

LATEST SFC MESOANALYSIS SHOWS CYCLONE BETWEEN CGI-DYR...WITH
COLLOCATED WEAK COLD FRONT AND PRONOUNCED PRESSURE TROUGH EXTENDING
SEWD IN AN ARC THROUGH MSL AREA...THEN JUST E OF MEI.  THIS BOUNDARY
SHOULD CONTINUE TO MOVE ENEWD ACROSS DISCUSSION AREA...WITH
POTENTIAL FOR TSTMS IN ITS PROXIMITY.  VIS AND REFLECTIVITY IMAGERY
INDICATE SHALLOW CONVECTIVE DEVELOPMENT BETWEEN MAURY COUNTY
TN...LAWRENCE AND GREENE COUNTIES AL.  SOME OF THIS ACTIVITY MAY
EVOLVE INTO TSTMS WITHIN ANOTHER 1-2 HOURS.

VERTICAL SHEAR PROFILES SUPPORT SUPERCELL AND/OR BOW DEVELOPMENT
WITH 0-6 KM SHEARS 50-60 KT...AND FAVORABLE VEERING OF WINDS WITH
HEIGHT E OF BOUNDARY.  HOWEVER...MODIFIED RAOBS AND RUC SOUNDINGS
INDICATE TN/NWRN AL CONVECTION WILL MOVE INTO WEAK/ELEVATED
INSTABILITY...I.E. MUCAPES AOB 400 J/KG ROOTED IN 800-850 MB LAYER.
FARTHER S...HOWEVER...CLOUD BREAKS EVIDENT IN VIS IMAGERY HAVE
ALLOWED  SFC TEMPS TO RISE INTO 70S AROUND TCL -- JUST AHEAD OF
TROUGH -- WITH DEW POINTS 65-68 DEG F. ACCORDINGLY MODIFIED
SOUNDINGS RESULT IN MLCAPES 250-500 J/KG...DEEPENING BUOYANT LAYER
AND BOOSTING EFFECTIVE SHEARS TO NEARLY 70 KT. CORRIDOR OF SVR
POTENTIAL OVER THIS AREA SHOULD BE THIN...WITH BOUNDARY LAYER
SLOWER TO DESTABILIZE ACROSS NERN AL.  AIR MASS BEHIND FRONT/TROUGH
IS CHARACTERIZED BY CLEARING OF CLOUD COVER...AND HAS DIABATICALLY
HEATED SUCH THAT SFC TEMPS ARE WARMER THAN E OF BOUNDARY.
HOWEVER...CONVECTIVE POTENTIAL WILL REMAIN LOW BECAUSE OF DRY
ADVECTION AND WEAK TO NO CONVERGENCE.

..EDWARDS.. 10/27/2006

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

ATTN...WFO...OHX...BMX...HUN...

33828787 34228751 34768764 35018784 35128751 35178722
34998648 34528649 33338702 32778803

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