[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 281945
SWOMCD
SPC MCD 281945 
MOZ000-ARZ000-OKZ000-282145-

MESOSCALE DISCUSSION 0702
NWS STORM PREDICTION CENTER NORMAN OK
0245 PM CDT THU APR 28 2005

AREAS AFFECTED...PARTS OF EXTREME ERN OK...SRN MO...AR

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 281945Z - 282145Z

TRENDS ARE BEING MONITORED FOR INCREASING SEVERE THREAT.  WW LIKELY
WILL BECOME NECESSARY LATER THIS AFTERNOON.

RAPID DESTABILIZATION IS UNDERWAY FROM THE ARKLATEX INTO THE OZARK
PLATEAU...BENEATH STRONG ZONAL SOUTHERN BRANCH JET ACROSS THE
SOUTHERN TIER STATES.  FIRST OF AT LEAST A COUPLE LOW AMPLITUDE
IMPULSES EMBEDDED WITHIN THIS REGIME IS NOW ACCELERATING INTO THE
LOWER OHIO/TENNESSEE VALLEY...WITH UPSTREAM SYSTEM ALREADY
PROGRESSING EASTWARD ACROSS THE TEXAS/OKLAHOMA PANHANDLE REGION.

IN RESPONSE TO LEAD SYSTEM...40 TO 50 KT SOUTHWESTERLY LOW-LEVEL JET
IS SLOWLY SHIFTING ACROSS ARKANSAS...PROVIDING FOCUS FOR LOW-LEVEL
THERMAL/MOISTURE ADVECTION.  STILL SOMEWHAT MARGINAL FOR INTENSE
CONVECTIVE DEVELOPMENT...SURFACE DEW POINTS ARE CLIMBING THROUGH THE
50S...BUT STEEP LAPSE RATES WILL COMPENSATE FOR LACK OF BETTER
MOISTURE.  

STRONG HEATING HAS OCCURRED SOUTH/SOUTHWEST OF CONVECTIVELY ENHANCED
BOUNDARY ACROSS CENTRAL ARKANSAS...WITH TEMPERATURES AROUND 80F
ACROSS EASTERN OKLAHOMA/SOUTHERN ARKANSAS.  THIS BOUNDARY IS
WEAKENING...AS MAIN BAROCLINIC ZONE DEVELOPS EAST OF OKLAHOMA
SURFACE LOW...ACROSS NORTHWEST ARKANSAS/SOUTHWEST MISSOURI. 
HOWEVER...BOTH BOUNDARIES COULD BECOME FOCUS FOR CONVECTIVE
DEVELOPMENT AS CAP WEAKENS AND FORCING INCREASES WITH APPROACH OF
UPSTREAM IMPULSE.

SIGNIFICANT INCREASE IN CONVECTIVE DEVELOPMENT MAY NOT OCCUR UNTIL
AFTER 29/00Z...BUT AT LEAST ISOLATED STORMS APPEAR POSSIBLE AS EARLY
AS 21-22Z ACROSS PARTS OF NORTHWEST AND CENTRAL ARKANSAS.  GIVEN
FAVORABLE SHEAR...MIXED LAYER CAPE INCREASING IN EXCESS OF 1000 J/KG
WILL BE SUPPORTIVE OF SUPERCELLS...PRIMARY WITH LARGE HAIL/DAMAGING
WIND GUSTS/

..KERR.. 04/28/2005

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

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

37079394 37389291 37309011 36688997 35639083 34669192
34079256 34339345 34599475 35419453 35759450 

WWWW