Tornado Watches Likely for Later (Upper MS Valley)
Posted: Sun Apr 18, 2004 11:51 am
MESOSCALE DISCUSSION 0367
NWS STORM PREDICTION CENTER NORMAN OK
1239 PM CDT SUN APR 18 2004
AREAS AFFECTED...CNTRL/NERN MN AND NWRN WI
CONCERNING...SEVERE THUNDERSTORM POTENTIAL
VALID 181739Z - 181945Z
POTENTIALLY VOLATILE SEVERE WEATHER SITUATION WAS BEGINNING TO
DEVELOP ACROSS PARTS OF THE UPPER MS VALLEY EARLY THIS AFTERNOON.TORNADO WATCHES WILL LIKELY BE NEED ACROSS THE REGION IN THE NEXT
FEW HOURS.
LATEST MESOANALYSIS PLACES DEEPENING SURFACE LOW OVER NERN SD...EAST
OF ABR...WITH VERY STRONG WARM FRONT EXTENDING EAST ACROSS CNTRL MN.
MEANWHILE...VERY STRONG MID LEVEL TROUGH AND ASSOCIATED 90-100KT
500MB WIND MAX WAS RACING NEWD FROM ERN CO/WRN NE AND WILL AID RAPID
INTENSIFICATION OF THE SURFACE LOW AND ASSOCIATED FRONTAL ZONES
THROUGH TONIGHT.
LATEST SHORT TERM MODEL GUIDANCE AND SATELLITE/RADAR TRENDS SEEM TO
SUGGEST THAT CONVECTION NORTH OF THE SURFACE WARM FRONT AND SURFACE
LOW SHOULD CONTINUE TO GRADUALLY STRENGTHEN AS INFLOW AIRMASS
CONTINUES TO DESTABILIZE AND LARGE SCALE ASCENT ACROSS THE WARM
FRONT INTENSIFIES. THIS ACTIVITY...SPREADING INTO THE ARROWHEAD OF
MN...WILL LIKELY ROTATE AND PRODUCE LARGE HAIL GIVEN VERY STRONG
DEEP LAYER SHEAR JUXTAPOSED 8-9 C/KM MID LEVEL LAPSE RATES.
LATER THIS AFTERNOON...AS WARM FRONT/SURFACE LOW DEVELOP
NWD/NEWD...AND EXIT REGION OF POWERFUL MID/UPPER JET OVERSPREADS THE
WARM SECTOR... FORCING ASSOCIATED WITH THESE FEATURES COUPLED WITH
STRONG INSOLATION AND RAPID ELIMINATION OF THE CAP SHOULD RESULT IN
WIDESPREAD TSTM DEVELOPMENT AND NUMEROUS SUPERCELLS. FCST SHEAR AND
INSTABILITY PARAMETERS NEAR THE LOW AND ALONG THE WARM FRONT ACROSS
MN SHOULD INITIALLY SUPPORT DISCRETE... POTENTIALLY
TORNADIC...STORMS ALONG WITH VERY LARGE HAIL AND HIGH WINDS.
..CARBIN.. 04/18/2004
PLEASE SEE http://WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DLH...MPX...FGF...ABR...
47189533 48499250 48059011 46499087 45859226 45099278
44719366 44889624 45519669 46309653
NWS STORM PREDICTION CENTER NORMAN OK
1239 PM CDT SUN APR 18 2004
AREAS AFFECTED...CNTRL/NERN MN AND NWRN WI
CONCERNING...SEVERE THUNDERSTORM POTENTIAL
VALID 181739Z - 181945Z
POTENTIALLY VOLATILE SEVERE WEATHER SITUATION WAS BEGINNING TO
DEVELOP ACROSS PARTS OF THE UPPER MS VALLEY EARLY THIS AFTERNOON.TORNADO WATCHES WILL LIKELY BE NEED ACROSS THE REGION IN THE NEXT
FEW HOURS.
LATEST MESOANALYSIS PLACES DEEPENING SURFACE LOW OVER NERN SD...EAST
OF ABR...WITH VERY STRONG WARM FRONT EXTENDING EAST ACROSS CNTRL MN.
MEANWHILE...VERY STRONG MID LEVEL TROUGH AND ASSOCIATED 90-100KT
500MB WIND MAX WAS RACING NEWD FROM ERN CO/WRN NE AND WILL AID RAPID
INTENSIFICATION OF THE SURFACE LOW AND ASSOCIATED FRONTAL ZONES
THROUGH TONIGHT.
LATEST SHORT TERM MODEL GUIDANCE AND SATELLITE/RADAR TRENDS SEEM TO
SUGGEST THAT CONVECTION NORTH OF THE SURFACE WARM FRONT AND SURFACE
LOW SHOULD CONTINUE TO GRADUALLY STRENGTHEN AS INFLOW AIRMASS
CONTINUES TO DESTABILIZE AND LARGE SCALE ASCENT ACROSS THE WARM
FRONT INTENSIFIES. THIS ACTIVITY...SPREADING INTO THE ARROWHEAD OF
MN...WILL LIKELY ROTATE AND PRODUCE LARGE HAIL GIVEN VERY STRONG
DEEP LAYER SHEAR JUXTAPOSED 8-9 C/KM MID LEVEL LAPSE RATES.
LATER THIS AFTERNOON...AS WARM FRONT/SURFACE LOW DEVELOP
NWD/NEWD...AND EXIT REGION OF POWERFUL MID/UPPER JET OVERSPREADS THE
WARM SECTOR... FORCING ASSOCIATED WITH THESE FEATURES COUPLED WITH
STRONG INSOLATION AND RAPID ELIMINATION OF THE CAP SHOULD RESULT IN
WIDESPREAD TSTM DEVELOPMENT AND NUMEROUS SUPERCELLS. FCST SHEAR AND
INSTABILITY PARAMETERS NEAR THE LOW AND ALONG THE WARM FRONT ACROSS
MN SHOULD INITIALLY SUPPORT DISCRETE... POTENTIALLY
TORNADIC...STORMS ALONG WITH VERY LARGE HAIL AND HIGH WINDS.
..CARBIN.. 04/18/2004
PLEASE SEE http://WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DLH...MPX...FGF...ABR...
47189533 48499250 48059011 46499087 45859226 45099278
44719366 44889624 45519669 46309653