MKC MCD 181447
IAZ000-MOZ000-ILZ000-181800-

SPC MESOSCALE DISCUSSION #0820 FOR S CNTRL...SE IA/NE MO/NRN IL
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

WE ARE MONITORING ONGOING CONVECTIVE DEVELOPMENT ACROSS REGION. WW
WILL LIKELY BE NEEDED WITHIN NEXT 1 TO 2 HOURS.

AT 13Z...999 MB SURFACE LOW WAS LOCATED NEAR OMAHA NEB WITH WARM
FRONT EXTENDING ACROSS SOUTH CENTRAL IOWA INTO NORTHERN ILLINOIS

...NORTHWEST OF DES MOINES/NORTH OF MOLINE AND SOUTH OF CHICAGO.
LOW-LEVEL CONVERGENCE IS FOCUSED ALONG THIS BOUNDARY...WITH LIFT
ENHANCED BY LEFT EXIT REGION OF 90+ KT 500 MB JET STREAK WHICH IS
NOW PROPAGATING OUT OF NORTHEAST KANSAS INTO NORTHWEST MISSOURI.
UPWARD VERTICAL MOTION FIELD HAS SUPPORTED RAPID NEW CONVECTIVE
DEVELOPMENT DURING THE PAST HOUR...ALONG FRONT TO THE NORTHWEST OF
DES MOINES.

AS MID-LEVEL JET STREAK CONTINUES EAST NORTHEASTWARD TOWARD NORTH
CENTRAL ILLINOIS LATE THIS MORNING AND AFTERNOON...CONVECTIVE
ACTIVITY IS EXPECTED TO CONTINUE TO INCREASE/INTENSIFY.
THUNDERSTORMS WILL DEVELOP NEAR/JUST SOUTH OF WARM FRONT ACROSS
SOUTH CENTRAL AND SOUTHEAST IOWA...AND AS FAR SOUTH AS MID-LEVEL
JET AXIS ALONG WEAK COLD FRONT/DRY LINE SURGING TOWARD NORTHEAST
MISSOURI...BEFORE ACTIVITY SPREADS INTO NORTHERN ILLINOIS. LAPSE
RATES ACROSS THIS REGION ARE STEEP AND CONTRIBUTING TO CAPE AOA
2000 J/KG... WHICH WILL SUPPORT SUPERCELLS AND A FEW TORNADOES IN
STRONGLY SHEARED ENVIRONMENT.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;408,0896 419,0814 399,0814 388,0896;
ACUS3 KMKC 181512
MKC MCD 181512
ILZ000-INZ000-181700-

SPC MESOSCALE DISCUSSION #0821 FOR CNTRL IL/NRN...CNTRL IND
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

WW WILL LIKELY BE REQUIRED SHORTLY.

RAPID CONVECTIVE DEVELOPMENT HAS OCCURRED NEAR CHAMPAIGN IL DURING
THE PAST HOUR...WITH SEVERE CELL ALREADY PRODUCING LARGE HAIL. NEW
ETA MODEL RUN SUGGESTS THIS ACTIVITY IS DEVELOPING WHERE 50 KT LOW-
LEVEL JET HAS ENHANCED LOW-LEVEL WARM ADVECTION...BENEATH MID/UPPER
JET AXIS WHICH WILL SUPPORT RAPID EASTWARD MOTION. IN STRONGLY
SHEARED ENVIRONMENT WITH CAPE AOA 2000 J/KG...STORMS WILL LIKELY
CONTINUE TO INCREASE/INTENSIFY WITH CONTINUING POTENTIAL FOR LARGE
HAIL...ALONG WITH INCREASING THREAT FOR DAMAGING WINDS/ISOLATED
TORNADOES.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;424,0818 432,0759 412,0759 404,0818;
ACUS3 KMKC 181600
MKC MCD 181600
NYZ000-PAZ000-181800-

SPC MESOSCALE DISCUSSION #0822 FOR NW/NCNTRL PA...WRN NY
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

WE WILL CONTINUE TO MONITOR EVOLUTION OF SQUALL LINE VICINITY OF
LAKE ERIE FOR POSSIBILITY OF WW BY THE TIME IT APPROACHES BUFFALO
NY/ERIE PA...POSSIBLY CLEVELAND OH AREAS IN THE 17/18Z TIME FRAME.
WEAK SHORT WAVE EMBEDDED WITHIN BELT OF STRONGER WESTERLIES OUT OF
THE PLAINS...ADVECTING AHEAD OF MORE VIGOROUS NORTHERN BRANCH SHORT
WAVE TROUGH OVER EASTERN ONTARIO...HAS PROVIDED SUPPORT FOR
ORGANIZED CLUSTER OF THUNDERSTORMS ACROSS SOUTHEAST ONTARIO/
EXTREME SOUTHEAST MICHIGAN. ACTIVITY IS CURRENTLY ALONG/JUST WEST
OF SURFACE COLD FRONT WHICH EXTENDS FROM 1004 MB SURFACE LOW...TO
THE WEST OF WATERTOWN NY...INTO THE SOUTHERN MICHIGAN/OHIO/INDIANA
BORDER AREA. STRONG MEAN FLOW ENVIRONMENT IS CONTRIBUTING TO
EASTWARD MOVEMENT IN EXCESS OF 50 KT...WHICH WILL SUPPORT
INCREASING THREAT FOR DAMAGING WINDS AS SQUALL LINE DEVELOPS INTO
DESTABILIZING WARM SECTOR AIR MASS OVER MUCH OF WESTERN NEW YORK/
NORTHERN PENNSYLVANIA.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;425,0936 408,0896 388,0896 405,0936;
ACUS3 KMKC 181642
MKC MCD 181642
IAZ000-ILZ000-181800-

SPC MESOSCALE DISCUSSION #0823 FOR SE IA...NW IL...NE MO
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 302

THREAT FOR TORNADOES APPEARS TO BE RAPIDLY INCREASING ACROSS PARTS
OF SOUTHEAST IOWA/NORTHWEST ILLINOIS.

CONVECTIVE CELL VICINITY OF OTTUMWA IA IS RAPIDLY INTENSIFYING IN
WARM SECTOR AIR MASS...WHERE LOW-LEVEL CONVERGENCE AND VERTICAL
SHEAR PROFILES ARE BECOMING MAXIMIZED IN LEFT EXIT REGION OF MID-
LEVEL JET STREAK CURRENTLY PROPAGATING ACROSS NORTH CENTRAL
MISSOURI. FORCING FOR UPWARD VERTICAL MOTION/SHEAR PROFILES ARE
BECOMING SUPPORTIVE OF TORNADIC SUPERCELLS...POSSIBLY WITH STRONG
TORNADOES...DEVELOPING EAST NORTHEAST INTO AREAS OF ILLINOIS
BOUNDED BY QUINCY/MOLINE AND PEORIA DURING THE NEXT 2 TO 4 HOURS.

..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;407,0862 424,0818 404,0818 387,0862;
ACUS3 KMKC 181714
MKC MCD 181710
INZ000-OHZ000-181900-

SPC MESOSCALE DISCUSSION #0824 FOR NRN/CNTRL IN...NW OH
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 301

WE WILL CONTINUE TO MONITOR CONVECTIVE ACTIVITY FOR POSSIBILITY OF
ADDITIONAL WW ACROSS NORTHWEST OHIO WITHIN THE NEXT 1 TO 2 HOURS.
CLUSTER OF INTENSE THUNDERSTORMS WITH EMBEDDED SUPERCELLS CONTINUES
TO DEVELOP EAST NORTHEASTWARD...ALONG MID/UPPER JET AXIS...WITH
ZONE OF STRONGER LOW-LEVEL WARM ADVECTION ASSOCIATED WITH SHORT
WAVE MIGRATING ACROSS IOWA/MISSOURI. SUPERCELL 30 MILES NORTH OF
INDIANAPOLIS AT 1705Z IS MOVING EAST AT 45 KT...AND IF IT PERSISTS

...WILL SPREAD ACROSS THE MUNCIE IND AREA INTO NORTHWEST OHIO IN
THE 18Z TO 20Z TIME FRAME.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;425,0936 408,0896 388,0896 405,0936;
ACUS3 KMKC 181725
MKC MCD 181725
SEZ000-IAZ000-182000-

SPC MESOSCALE DISCUSSION #0825 FOR SE IA
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 302

EAST-WEST BOUNDARY READILY EVIDENT IN RADAR IMAGERY THROUGH
DAVENPORT IA INTO THE CEDAR RAPIDS AREA IS ENHANCING SUPERCELL JUST
SOUTH OF CEDAR RAPIDS IA...AS BOUNDARY MOVES SOUTH AROUND 10 KTS.
BOUNDARY APPEARS LIKELY TO FURTHER ENHANCE THREAT FOR TORNADOES
WITH SUPERCELLS DEVELOPING TO THE SOUTH...ACROSS WASHINGTON/JOHNSON
/MUSCATINE/LOUISA COUNTIES NEXT 1 TO 2 HOURS.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;323,1005 372,0958 352,0958 303,1005;
ACUS3 KMKC 181825
MKC MCD 181825
TXZ000-182100-

SPC MESOSCALE DISCUSSION #0826 FOR PARTS OF CNTRL/NRN TX/SE OK
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

WE ARE MONITORING CONVECTIVE DEVELOPMENT/CAP STRENGTH ALONG FRONT
ACROSS THE SOUTHERN PLAINS FOR POSSIBILITY OF WW BY 20/21Z.
LOW-LEVEL WARM ADVECTION PERSISTS AHEAD OF SOUTHERN PLAINS COLD
FRONT...BENEATH SHORT WAVE RIDGE BUILDING AHEAD OF SOUTHERN PLATEAU
SHORT WAVE TROUGH. DESPITE MID/HIGH-LEVEL SUBSIDENCE...CONVERGENCE
ALONG FRONT APPEARS TO BE WEAKENING CAP...AS REFLECTED BY 18Z RAOB
FROM FORT WORTH. 18Z SURFACE ANALYSIS INDICATED THAT COLD FRONT
CURVES FROM JUST EAST OF MUSKOGEE AND ARDMORE OK INTO AREAS OF WEST
CENTRAL TEXAS BETWEEN ABILENE AND SAN ANGELO. BOUNDARY IS BECOMING
FOCUS FOR DEEPENING CONVECTIVE DEVELOPMENT...WHICH MAY CONTINUE TO
STRENGTHEN WITH ADDITIONAL DAYTIME HEATING. GIVEN STEEP LAPSE
RATES AND MODERATELY STRONG POTENTIAL INSTABILITY WITH CAPE OF 2000
TO 3000 J/KG...SHEAR PROFILES ENHANCED BY BAND OF STRONGER
SOUTHWESTERLY MID/UPPER FLOW WILL ENHANCE POTENTIAL FOR SEVERE
STORMS WITH LARGE HAIL/DAMAGING WIND GUSTS.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;437,0759 438,0710 408,0710 407,0759;
ACUS3 KMKC 181843
MKC MCD 181843
NYZ000-PAZ000-181900-

SPC MESOSCALE DISCUSSION #0827 FOR SE NY/NE PA/WRN MA/CT/NRN NJ
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

WW MAY BE REQUIRED SOON.

SQUALL LINE CONTINUES TO INTENSIFY AND RACE EASTWARD IN EXCESS OF
50 KT...ACROSS SOUTHERN NEW YORK/NORTH PENNSYLVANIA. WITH STRONGER
PRESSURE FALLS OCCURRING ACROSS MUCH OF NEW ENGLAND...MOIST
UNSTABLE AIR MASS IS ADVECTING AHEAD OF ACTIVITY INTO THE NORTHERN
MID ATLANTIC COAST REGION AND SOUTHERN NEW ENGLAND...AND WILL
SUPPORT INCREASING DAMAGING WIND POTENTIAL THROUGH EARLY EVENING.

..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;397,0903 428,0876 408,0876 377,0903;
ACUS3 KMKC 181906
MKC MCD 181906
ILZ000-182100-

SPC MESOSCALE DISCUSSION #0828 FOR NW/CNTRL IL
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

BAROCLINIC ZONE ASSOCIATED WITH SURFACE FRONT...EXTENDING FROM
KANKAKEE COUNTY IL INTO AREAS JUST SOUTH OF MOLINE..WILL CONTINUE
TO ENHANCE THREAT FOR TORNADOES WITH SUPERCELLS...AS BOUNDARY MOVES
SLOWLY SOUTHWARD NEXT FEW HOURS. UPWARD VERTICAL MOTION FIELD
BENEATH LEFT EXIT REGION OF MID/UPPER JET IS BEGINNING TO SPREAD
INTO NORTH CENTRAL ILLINOIS...AND WILL BEGIN TO SUPPORT SUPERCELL
DEVELOPMENT SOUTHWARD ALONG/AHEAD OF DRY LINE...TOWARD PEORIA/
SPRINGFIELD AREAS NEXT FEW HOURS.


..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;427,0855 400,0838 400,0818 427,0835;
ACUS3 KMKC 181958
MKC MCD 181958
MIZ000-OHZ000-182200-

SPC MESOSCALE DISCUSSION #0830 FOR SRN LWR MI/NW OH
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 303

STRONG/SEVERE THUNDERSTORMS PERSIST IN FRONTAL ZONE ALONG THE
MICHIGAN/OHIO/INDIANA BORDER WHICH HAS BEGUN TO SHIFT SLIGHTLY
NORTHWARD AS WARM FRONT IN RESPONSE TO UPSTREAM SHORT WAVE. SOUTH
OF FRONT...ALTHOUGH INITIAL CELLS HAVE WEAKENED IN DRIER MORE
STABLE AIR MASS ACROSS CENTRAL/SOUTHERN OHIO...FORCING ALONG
CONVECTIVE BOUNDARY ON NOSE OF SOUTHWESTERLY LOW-LEVEL JET ACROSS
THE LOWER OHIO VALLEY WILL LIKELY MAINTAIN STRONG/SEVERE CONVECTIVE
DEVELOPMENT NEAR THE INDIANA/OHIO BORDER NEXT FEW HOURS.

..KERR.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;387,0921 414,0889 394,0889 367,0921;
ACUS3 KMKC 182141
MKC MCD 182141
MOZ000-ILZ000-190000-

SPC MESOSCALE DISCUSSION #0832 FOR ..ERN MO/CENTRAL IL..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 305.

LINE OF WIDELY SCATTERED SUPERCELL THUNDERSTORMS HAVE DEVELOPED
ALONG SURFACE COLD FRONT NEAR STL. LATEST SURFACE ANALYSIS
INDICATES WINDS IN THE BLV AREA ARE SLIGHTLY MORE BACKED THAN IN
SURROUNDING REGIONS...ENHANCING LOW LEVEL SHEAR AND CONVERGENCE
WITH ACTIVITY NEAR STL/ALN. 3KM HELICITY VALUES AROUND 200 M2/S2
AND CAPE VALUES OVER 3000 J/KG APPEAR FAVORABLE FOR CONTINUED
SEVERE STORMS WITH POTENTIAL FOR ISOLATED TORNADOES.
OTHER ISOLATED SUPERCELL STORMS HAVE FORMED WEST OF PIA. THESE
STORMS ARE JUST SOUTH OF SURFACE WARM FRONT AND IN REGION OF STRONG
DYNAMIC LIFT. THESE STORMS WILL POSE THREAT OF LARGE HAIL AND
ISOLATED TORNADOES FOR THE NEXT FEW HOURS AS THEY TRACK
NORTHEASTWARD INTO NORTHEAST IL.

NEW WATCH WILL LIKELY BE REQUIRED AHEAD OF THESE STORMS OVER PARTS
OF EASTERN IL AND NORTHERN IND WITHIN THE NEXT 1-2 HOURS.

..HART.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;427,0748 433,0710 413,0710 407,0748;
ACUS3 KMKC 182218
MKC MCD 182218
NYZ000-NJZ000-CTZ000-MAZ000-NHZ000-NYZ000-RI VTZ000-190100-

SPC MESOSCALE DISCUSSION #0833 FOR
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 307...308.

SQUALL LINE WILL CONTINUE TO PRODUCE SCATTERED WIND GUSTS OF 50-60
KTS AS IT MOVES 290/50KTS THROUGH THE TRI-STATE AREA AND SOUTHERN
NEW ENGLAND. INTENSITY OF NRN HALF OF SQUALL LINE WILL GRADUALLY
DIMINISH AFTER 18/2330Z AS CONVECTION INTERACTS WITH MARINE LAYER
ALONG THE NEW ENGLAND S-COAST AND LONG ISLAND.

STRONG SURFACE PRESSURE FALLS CONTINUE IN ADVANCE OF SQUALL
LINE...WITH NARROW AXIS OF LOW TO MID 60 DEWPOINTS EXTENDING FROM
W-CENTRAL ME SWWD INTO THE N-VIRGINIA. LINE IS EXPECTED TO REMAIN
SEVERE...WITH DAMAGING WIND GUSTS THE PRIMARY THREAT. LINE MAY
BRIEFLY INTENSIFY ALONG SURFACE CONVERGENCE ZONE FROM NYC NEWD
ALONG THE CT COAST. STABLE LOW-LEVEL AIR ACROSS LONG ISLAND/SERN
NEW ENGLAND WILL THEREAFTER RESULT IN MORE ISOLATED SEVERE
POTENTIAL AS LINE APPROACHES THE SHORE. SURFACE SWLY FLOW SHOULD
ALLOW LINE TO REMAIN RELATIVELY STEADY STATE THROUGH TO THE COAST
OF NJ.


..BANACOS.. 05/18/00
NNNN
ZCZC MKCSWOMCD ALL;323,1005 357,0922 337,0922 303,1005;
ACUS3 KMKC 182225
MKC MCD 182225
TXZ000-OKZ000-ARZ000-190100-

SPC MESOSCALE DISCUSSION #0834 FOR ..NRN TX/SERN OK..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL/HEAVY RAIN...REF WW 306.

NUMEROUS STRONG/SEVERE THUNDERSTORMS EXTEND ALONG SURFACE FRONT
FROM SOUTHEAST OK INTO NORTH-CENTRAL TX. DESPITE WEAK SHEAR
PARAMETERS...HIGH CAPE VALUES AND STEEP LAPSE RATES COMBINED WITH
STRONG MID/HIGH LEVEL WINDS ARE SUPPORTING SUPERCELL STRUCTURES
WITH SEVERAL CELL SPLITS NOTED. RELATIVELY WEAK CAP AND PERSISTENT
CONVERGENCE NEAR/WEST OF FTW SHOULD RESULT IN CONTINUED RE-
DEVELOPMENT OF STORMS IN THIS REGION FOR SEVERAL MORE HOURS.
CORRIDOR FROM MWL TO NORTH OF FTW TO NORTH OF PRX MAY ALSO
EXPERIENCE VERY HEAVY RAINFALL DURING THE NEXT FEW HOURS.
NEW CELLS HAVE BEGUN TO DEVELOP FARTHER SOUTHWEST ALONG FRONT OVER
COLEMAN/CALLAHAN COUNTIES TX. MODEL GUIDANCE SUGGESTS THAT
INCREASING SOUTHEASTERLY LOW LEVEL WINDS AFTER 00Z WILL ENHANCE
FORCING AND AID INITIATION IN THIS AREA. IF ACTIVITY CONTINUES TO
INTENSIFY...NEW WW MAY BE REQUIRED IN THIS REGION.

..HART.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;416,0896 427,0863 407,0863 396,0896;
ACUS3 KMKC 182330
MKC MCD 182330
ILZ000-190200-

SPC MESOSCALE DISCUSSION #0835 FOR ..NERN IL/NWRN IND..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 309.

TORNADIC SUPERCELL OVER LIVINGSTON/KANKAKEE COUNTIES IL IS MOVING
EASTWARD TOWARD THE IND BORDER. RADAR AND SURFACE ANALYSES
INDICATE THAT STORM IS TRACKING ALONG SURFACE QUASI-STATIONARY
FRONT WHERE LOW LEVEL SHEAR IS MAXIMIZED. LATEST SFCOA GUIDANCE
SHOWS CAPE VALUES OF 2000-2500 J/KG AND HELICITY VALUES OF 200-300
M2/S2 ALONG BOUNDARY. CURRENT TORNADIC STORM MAY BE FOLLOWED BY
OTHER UPSTREAM CELLS WITH A CONTINUED THREAT OF LARGE HAIL AND
TORNADOES.

WELL-DEFINED BOW ECHO IS NOW APPROACHING THE SOUTHERN SUBURBS OF
CHI. HOWEVER...THIS IS JUST NORTH OF THE WARM FRONT WITH STABLE
SURFACE CONDITIONS NOTED. THIS STABLE LAYER SHOULD LIMIT THREAT OF
WIDESPREAD DAMAGING WINDS.


..HART.. 05/18/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;338,0973 357,0922 337,0922 318,0973;
ACUS3 KMKC 190011
MKC MCD 190011
OKZ000-ARZ000-190300-

SPC MESOSCALE DISCUSSION #0836 FOR ..SERN OK/WRN AR..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL/HEAVY RAIN...REF WW 306.

LINE OF STRONG THUNDERSTORMS EXTENDS FROM THE PRX AREA
NORTHEASTWARD INTO WEST CENTRAL AR. THESE STORMS ARE ALONG AND
JUST SOUTH OF SURFACE COLD FRONT...WHERE DEWPOINTS IN THE UPPER 60S
ARE RESULTING IN CAPE VALUES AROUND 3500 J/KG. DEEP LAYER SHEAR
HAS RESULTED IN ISOLATED SUPERCELLS ALONG THIS LINE...BUT WEAK LOW
LEVEL SHEAR HAS LIMITED THE TORNADO THREAT. ACTIVITY WILL CONTINUE
TO SPREAD EASTWARD ACROSS CENTRAL AR DURING THE NEXT FEW
HOURS...WITH THREAT OF LARGE HAIL AND DAMAGING WINDS IN STRONGER
CELLS.

SLOW MOVEMENT OF STORMS AND TRAINING OF CELLS ALONG COLD
FRONT/OUTFLOW BOUNDARIES WILL LIKELY RESULT IN A PROLONGED PERIOD
OF HEAVY RAINFALL FROM CHOCTAW COUNTY OK INTO POLK COUNTY AR.

..HART.. 05/19/00
NNNN
ZCZC MKCSWOMCD ALL;438,0855 425,0838 405,0838 418,0855;
ACUS3 KMKC 190043
MKC MCD 190043
MIZ000-OHZ000-190600-

SPC MESOSCALE DISCUSSION #0837 FOR SRN LOWER MI AND NWRN OH...
CONCERNING...HEAVY RAINFALL...

RAINFALL RATES OF AROUND 1 INCH PER HOUR ARE EXPECTED OVER PORTIONS
OF SRN LOWER MI AND NWRN OH THROUGH 19/06Z.

CURRENT SURFACE ANALYSIS SHOWS A STRONG E-W ORIENTED BAROCLINIC
ZONE EXTENDING FROM NRN IL EWD INTO NRN PA. THE FRONTAL ZONE HAS
BEEN MOVING VERY SLOWLY SWD DURING THE PAST SEVERAL HOURS. AHEAD OF
WELL-DEFINED UPPER VORTICITY MAX OVER ERN IA...ISENTROPIC LIFT IS
TAKING PLACE IN BROAD WSWLY FLOW ALONG THE FRONTAL SURFACE.
FURTHER...MINIMAL ELEVATED CAPE VALUES IN THE 500-1000 J/KG RANGE
ARE EXPECTED TO PERSIST AS SWLY LOW-LEVEL JET INTENSIFIES TO AROUND
50 KTS DURING THE OVERNIGHT PERIOD. THIS WILL SUSTAIN EMBEDDED
CONVECTIVE RAINFALL NORTH OF THE SURFACE FRONTAL POSITION...WITH
RATES GENERALLY AROUND 1 INCH PER HOUR THROUGH 19/06Z.

..BANACOS.. 05/19/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL;414,0889 409,0842 389,0842 394,0889;
ACUS3 KMKC 190134
MKC MCD 190134
ILZ000-INZ000-OHZ000-190400-

SPC MESOSCALE DISCUSSION #0838 FOR ..NRN IND/WRN OH..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 309.

LINE OF SEVERE STORMS EXTENDS FROM ELKHART/MARSHALL COUNTIES IND
SOUTHWARD TO JUST SOUTH OF SPI. SEVERAL CELLS ALONG THIS LINE HAVE
PRODUCED TORNADOES DURING THE PAST 1-2 HOURS. NORTHERN END OF LINE
IS MOVING INTO A REGION OF WIDESPREAD SHOWERS OVER NORTHERN
IND...WHICH LIKELY STABILIZED THE REGION AND SHOULD LIMIT SEVERE
POTENTIAL. HOWEVER...CELLS ALONG AND JUST SOUTH OF THE WARM FRONT
OVER NORTHWEST IND MAY STILL POSE A THREAT FOR LARGE
HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES FOR ANOTHER 1-2
HOURS.

NEW WW WILL LIKELY BE ISSUED SOON AHEAD OF STORMS OVER PORTIONS OF
EASTERN IND AND OH.


..HART.. 05/19/00
NNNN
ZCZC MKCSWOMCD ALL;323,1005 344,0940 324,0940 303,1005;
ACUS3 KMKC 190330
MKC MCD 190330
TXZ000-OKZ000-190600-

SPC MESOSCALE DISCUSSION #0839 FOR ..CNTRL/NERN TX AND SERN OK..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL/HEAVY RAIN...REF WW 310.

ISOLATED LARGE SUPERCELL REMAINS OVER COLEMAN/BROWN COUNTIES
TX...WITH OTHER ACTIVITY NOW FORMING WEST OF SJT ALONG COLD FRONT.
SOUTHEASTERLY LOW LEVEL WINDS HAVE INCREASED IN THIS AREA ENHANCING
WARM ADVECTION AND AIDING DEVELOPMENT OF NEW CONVECTION. THIS
ACTIVITY WILL REMAIN CAPABLE OF LARGE HAIL FOR 2-3 MORE HOURS.
LINE OF THUNDERSTORMS EXTENDS FROM JUST NORTH OF FTW TO PRX TO
MCCURTAIN COUNTY OK. THIS AXIS HAS EXPERIENCED SEVERAL ROUNDS OF
CONVECTION THIS EVENING...WITH FURTHER TRAINING OF CELLS EXPECTED.
LOCAL RAINFALL RATES OF 1-2 INCHES PER HOUR ARE POSSIBLE ALONG THIS
AXIS.


..HART.. 05/19/00
NNNN
ZCZC MKCSWOMCD ALL;407,0862 424,0818 404,0818 387,0862;
ACUS3 KMKC 190416
MKC MCD 190416
INZ000-OHZ000-190700-

SPC MESOSCALE DISCUSSION #0840 FOR ..NERN IND/NWRN OH..
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 311.

LINE OF STRONG THUNDERSTORMS EXTENDS FROM MONTGOMERY COUNTY IND
NORTHEASTWARD TO THE FDY AREA. RADAR LOOPS INDICATE THAT OUTFLOW
BOUNDARY HAS SURGED AHEAD OF THESE STORMS...SUGGESTING A DECREASE
IN THE POTENTIAL FOR DAMAGING WINDS. ALSO...SCATTERED THUNDERSTORM
DEVELOPMENT AHEAD OF PRIMARY CONVECTIVE LINE HAS STABILIZED AIRMASS
ACROSS NORTHEASTERN IND/NORTHERN OH AND IS LESSENING THE SEVERE
THREAT.

ISOLATED CELLS IN THIS REGION MAY PRODUCE LARGE HAIL FOR ANOTHER 1-
2 HOURS...BUT PRIMARY SEVERE THREAT APPEARS TO BE DIMINISHING. IF
PRESENT TRENDS CONTINUE...WW 311 MAY BE CANCELLED BEFORE
EXPIRATION.


..HART.. 05/19/00
NNNN
ZCZC MKCSWOMCD ALL;409,0819 422,0769 402,0769 389,0819;
ACUS3 KMKC 190646
MKC MCD 190646
OHZ000-PAZ000-190900-

SPC MESOSCALE DISCUSSION #0841 FOR EXTREME EASTERN
OHIO/PENNSYLVANIA
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 312...

STRONG THUNDERSTORMS CONTINUE TO MOVE EASTWARD THROUGH PORTIONS OF
EXTREME EASTERN OHIO AS WELL AS SOUTHERN PENNSYLVANIA. THE AIR
MASS ACROSS A LARGE PART OF PENNSYLVANIA HAS STABILIZED SOMEWHAT
DURING THE PAST COUPLE OF HOURS...BUT THERE APPEARS TO STILL BE
SUFFICIENT INSTABILITY ACROSS THE SOUTHERN PART OF THE WATCH AREA.
AS TIME GOES BY...THE ACTIVITY SHOULD EVOLVE INTO MORE OF A HEAVY
RAIN THREAT ACROSS SOUTHERN AND CENTRAL PORTIONS OF PENNSYLVANIA.

..REHBEIN.. 05/19/00

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