[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 212337
SWOMCD
SPC MCD 212336 
MSZ000-LAZ000-ARZ000-220130-

MESOSCALE DISCUSSION 1370
NWS STORM PREDICTION CENTER NORMAN OK
0636 PM CDT MON JUN 21 2004

AREAS AFFECTED...PORTIONS NRN LA...SERN AR...W-CENTRAL MS

CONCERNING...SEVERE THUNDERSTORM POTENTIAL...HEAVY RAINFALL 

VALID 212336Z - 220130Z

LEADING OUTFLOW BOUNDARIES FROM TWO ONGOING CONVECTIVE COMPLEXES MAY
MERGE BETWEEN SHV-GWO OVER NEXT 2-3 HOURS...BRIEFLY RESULTING IN
ENHANCED LOW LEVEL LIFT AND SEVERE GUST/HAIL POTENTIAL.  THEREAFTER
COLLECTIVE CONVECTIVE MASS SHOULD WEAKEN BECAUSE OF INGESTION OF
INCREASINGLY COOL/STABLE AIR RESULTING FROM BOTH DIABATIC SFC
COOLING AND OUTFLOW.  LOCALIZED HEAVY RAIN IS LIKELY TOO...WITH
RATES UP TO NEAR 3 INCHES/HOUR EXPECTED.

TSTMS THAT ORIGINATED ON GULF COAST SEA BREEZE GENERALLY ARE MOVING
NWD 15-20 KT ACROSS CENTRAL LA AND SRN MS.  IRREGULARLY SHAPED
COLLECTION OF OUTFLOW BOUNDARIES PRECEDES MUCH OF THIS ACTIVITY AND
IS MOVING NWD AS WELL. MEANWHILE SOMEWHAT BETTER ORGANIZED LINE OF
TSTMS OVER SERN AR AND WRN PORTIONS LA/AR BORDER REGION IS MOVING
SEWD APPROXIMATELY 25 KT.  THIS ACTIVITY CARRIES MARGINAL LARGE HAIL
THREAT AND POTENTIAL FOR GUSTS THAT ARE BELOW 50 KT SEVERE
CRITERIA...BUT STILL CAPABLE OF OCCASIONAL DAMAGE.  ADDITIONAL TSTMS
MAY DEVELOP IN DISCUSSION AREA WHEN THEIR OUTFLOWS MERGE --
INITIALLY OVER BIENVILLE PARISH AROUND 0030Z AND SOMEWHAT LATER
FARTHER ENE.  IN BETWEEN THESE SYSTEMS...VERY MOIST BOUNDARY LAYER
COMBINED WITH AROUND 3500-400O J/KG MLCAPE MAY CONTRIBUTE TO
POTENTIAL FOR DAMAGING WET DOWNBURSTS WITH ANY TSTMS THAT DEVELOP. 
1.75-2 INCH PW AND 18-19 G/KG MEAN MIXING RATIOS...GIVEN LARGE
AVAILABLE CAPE...SUGGEST TSTMS WILL BE PROLIFIC RAIN PRODUCERS AS
WELL.

..EDWARDS.. 06/21/2004

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

ATTN...WFO...JAN...SHV...

32489156 32229265 32099336 32459362 32729334 33189156
33599085 33339035 32819047 32619106 

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