MESOSCALE DISCUSSION NWS STORM PREDICTION CENTER

[CaptinCrunch]

MESOSCALE DISCUSSION 0903
NWS STORM PREDICTION CENTER NORMAN OK
0129 PM CDT WED MAY 18 2005

AREAS AFFECTED...CNTRL/SRN VA AND NRN NC

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 181829Z - 182030Z



TSTMS EXPECTED TO DEVELOP/SPREAD SEWD THROUGH MID/LATE AFTERNOON
ACROSS PORTIONS OF CNTRL/SRN VA AND NRN NC. ALTHOUGH NOT CURRENTLY
ANTICIPATED...TRENDS WILL CONTINUE TO BE MONITORED FOR A POSSIBLE
SEVERE WATCH.

CU FIELD CONTINUES TO DEEPEN/EVOLVE ALONG LEE OF APPALACHIANS WITH
DOWNSTREAM AIRMASS WARMING WELL THROUGH THE MID/UPPER 70S AT 18Z
AMIDST GENEROUS INSOLATION. MODIFIED 12Z OBSERVED RAOBS IN
ACCORDANCE WITH RUC SOUNDINGS SUGGESTS NEGLIGIBLE CINH NOW
EXISTS...WITH POTENTIAL FOR 750-1250 J/KG SBCAPE. REGION REMAINS ON
PERIPHERY OF MODERATE CYCLONIC MID LEVEL W/NW FLOW...THUS 30-35 KTS
/RELATIVELY HIGHER ACROSS VA/ WOULD CONTRIBUTE TO STORM ORGANIZATION
AS ACTIVITY EVOLVES SEWD THROUGH THE AFTERNOON. AT LEAST MARGINALLY
SEVERE HAIL/ISOLD DAMAGING WINDS GUSTS APPEARS POSSIBLE WITH THE
MOST VIGOROUS TSTMS MID/LATE AFTERNOON GIVEN INSTABILITY/RELATIVELY
MIXED BOUNDARY LAYER. TRENDS WILL CONTINUE TO BE MONITORED.

[CaptinCrunch]

MESOSCALE DISCUSSION 0904
NWS STORM PREDICTION CENTER NORMAN OK
0150 PM CDT WED MAY 18 2005

AREAS AFFECTED...SOUTHEAST KS...NORTHERN OK

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 181850Z - 182045Z



SCATTERED STRONG/SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER
SOUTHEAST KS/NORTHERN OK DURING THE NEXT FEW HOURS. WW WILL LIKELY
BE REQUIRED IN THE NEXT 1-2 HOURS.

LATEST SURFACE ANALYSIS SHOWS WEAKENING SURFACE COLD FRONT EXTENDING
ROUGHLY FROM MHK-P28-GAG. SCATTERED LOW/MID CLOUDS EAST OF THE
BOUNDARY HAVE RETARDED DAYTIME HEATING SOMEWHAT. HOWEVER...STRONG
HEATING IS OCCURRING IMMEDIATELY WEST OF BOUNDARY OVER CENTRAL KS
INTO THE NORTHERN TX PANHANDLE. THESE STEEP LOW LEVEL LAPSE RATES
COUPLED WITH INCREASING SURFACE DEWPOINTS ARE EXPECTED TO HELP BREAK
CAP IN THE NEXT FEW HOURS. LATEST RUC GUIDANCE SUGGESTS INITIATION
WILL OCCUR NEAR SURFACE FRONT/DRYLINE INTERSECTION NEAR P28. OTHER
STORMS ARE LIKELY TO DEVELOP NORTHEASTWARD ALONG FRONT INTO EASTERN
KS...AND PERHAPS SOUTHWARD INTO NORTHERN OK LATER THIS AFTERNOON.
VERTICAL SHEAR PROFILES APPEAR FAVORABLE FOR SUPERCELL STORMS
CAPABLE OF LARGE HAIL AND DAMAGING WINDS.

[CaptinCrunch]

MESOSCALE DISCUSSION 0905
NWS STORM PREDICTION CENTER NORMAN OK
0242 PM CDT WED MAY 18 2005

AREAS AFFECTED...WRN PENINSULA/ERN PANHANDLE OF FL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 181942Z - 182145Z



TSTMS EXPECTED TO CONTINUE TO DEVELOP ACROSS WRN PENINSULA/ERN
PANHANDLE OF FL THROUGH MID/LATE AFTERNOON...WITH POTENTIAL FOR
ISOLD STRONG WIND GUSTS/MARGINALLY SEVERE HAIL. SEVERE WATCH IS NOT
EXPECTED.

CU FIELD CONTINUES TO GRADUALLY DEEPEN ACROSS THE CNTRL/WRN FL
PENINSULA ATTM...WITH TSTMS ALREADY ONGOING ACROSS THE ERN FL
PANHANDLE. WITH UPPER TROUGH AXIS BISECTING NRN FL...UPPER COOL
POCKET -- AROUND -12 C AT 500 MB PER 12Z TBW/TLH/JAX AND 15Z XMR
RAOBS -- IS CONTRIBUTING TO SLIGHTLY STEEPER MID LEVEL LAPSE RATES
IN COMPARISON TO YESTERDAY. ALTHOUGH SFC CONVERGENCE REMAINS
MARGINAL AT MID AFTERNOON ACROSS THE SRN HALF OF THE FL
PENINSULA...GREATER SHEAR PROFILES EXIST PROGRESSIVELY SWD ACROSS
CNTRL/SRN FL OWING TO BOTH STRONGER MID LEVEL WLY FLOW/LOW LEVEL ELY
FLOW.

AS TSTMS CONTINUE TO DEVELOP THIS AFTERNOON...MODERATE INSTABILITY
IN ACCORDANCE WITH MODEST SHEAR SUGGESTS POTENTIAL FOR PULSE-TYPE
STRONG WIND GUSTS/MARGINALLY SEVERE HAIL THROUGH LATE AFTERNOON.
EXPECTED MARGINAL/ISOLD NATURE WILL LIKELY PRECLUDE A SEVERE WATCH.

[CaptinCrunch]

MESOSCALE DISCUSSION 0910
NWS STORM PREDICTION CENTER NORMAN OK
1044 AM CDT THU MAY 19 2005

AREAS AFFECTED...SRN MO/IL/IND...NRN AR...WRN KY

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 191544Z - 191815Z



TSTMS ARE EXPECTED TO DEVELOP ACROSS SRN/SERN MO...NRN AR...SRN
IL/IND AND WRN KY OVER THE NEXT FEW HOURS. SEVERE THREAT IN THE FORM
OF HAIL AND HIGH WINDS SHOULD INCREASE THROUGH THE AFTERNOON AND A
WATCH MAY BE NEEDED.

INCREASINGLY UNSTABLE AND WEAKLY CAPPED WARM SECTOR WILL YIELD TO
SFC-BASED TSTM DEVELOPMENT OVER THE NEXT FEW HOURS AS SFC HEATING
EFFECTIVELY ELIMINATES INHIBITION. FOCUS FOR STORM DEVELOPMENT
SHOULD BE NEAR/ALONG A WEAKLY CONVERGENT LOW LEVEL BOUNDARY
EXTENDING FROM NRN AR/SRN MO...NEWD TO SCNTRL IL. THIS BOUNDARY
INTERSECTS AN OUTFLOW/DIFFERENTIAL HEATING BOUNDARY OVER SERN IL AND
THE OUTFLOW/WARM FRONT EXTENDS EWD FROM THIS AREA ACROSS SRN OH.
THESE BOUNDARIES WILL FURTHER SERVE TO FOCUS STORM DEVELOPMENT INTO
THE AFTERNOON.

STEEP LOW TO MID LEVEL LAPSE RATES AROUND 7 C/KM ATOP MOISTENING
BOUNDARY LAYER WILL CONTRIBUTE TO RELATIVELY HIGH MLCAPE VALUES
REACHING 1500-2000 J/KG BY AFTERNOON. DEEP LAYER SHEAR VALUES OF
20-25 KT ARE CURRENTLY UNSUPPORTIVE OF SUPERCELLS...AND WOULD
SUGGEST INITIAL ACTIVITY MAY STRUGGLE TO ORGANIZE. HOWEVER...FCST
SOUNDINGS APPEAR TO SUGGEST A GRADUAL INCREASE IN DEEP LAYER SHEAR
AS MID LEVEL JET STREAK...CURRENTLY ACROSS IA/NRN IL...SPREADS SEWD
TOWARD THE MO BOOTHEEL AND LWR OH VLY LATER THIS AFTERNOON.

GIVEN MAGNITUDE OF CAPE AS WELL AS INCREASING STORM COVERAGE AND
SHEAR...A WATCH OR WATCHES WILL PROBABLY BE NEEDED ACROSS THE REGION
BY EARLY AFTERNOON.

[CaptinCrunch]

MESOSCALE DISCUSSION 0911
NWS STORM PREDICTION CENTER NORMAN OK
1241 PM CDT THU MAY 19 2005

AREAS AFFECTED...ERN IA...SRN WI...NRN IL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 191741Z - 191945Z



ISOLATED SEVERE THUNDERSTORM DEVELOPMENT POSSIBLE IN THE NEXT FEW
HOURS ACROSS PARTS OF EASTERN IA...SOUTHERN WI...AND NORTHERN IL.
WW MAY BE NEEDED.

LATEST SURFACE ANALYSIS SHOWS A LOW JUST EAST OF MSP...WITH SERIES
OF BOUNDARIES ARCING ACROSS PARTS OF IA/IL/WI INTO LOW. ONE
BOUNDARY EXTENDS FROM NEAR FRM TO ALO...THEN CURVING NORTHWARD INTO
SOUTHWEST WI. AN INCREASING CU FIELD ALONG THIS BOUNDARY SUGGESTS
CONVECTIVE DEVELOPMENT MAY OCCUR SOON. AIR MASS OVER THIS REGION IS
RELATIVELY MOIST AND MODERATELY UNSTABLE WITH DEWPOINTS NEAR 60F AND
MLCAPE VALUES OF OVER 1000 J/KG. STRONG DEEP LAYER VERTICAL SHEAR
IS IN PLACE...ALONG WITH LOCALLY BACKED SURFACE WINDS OVER NORTHERN
IL. THESE FACTORS MAY AID IN THE DEVELOPMENT OF ISOLATED
SEVERE/SUPERCELL THUNDERSTORMS. IF LOW LEVEL WINDS CAN REMAIN
BACKED THROUGH THE AFTERNOON...ISOLATED TORNADOES WOULD ALSO BE
POSSIBLE INVOF BOUNDARIES. OTHERWISE...LARGE HAIL IS LIKELY THE
MAIN THREAT. AREA IS BEING MONITORED FOR POSSIBLE WW.

[CaptinCrunch]

MESOSCALE DISCUSSION 0912
NWS STORM PREDICTION CENTER NORMAN OK
0115 PM CDT THU MAY 19 2005

AREAS AFFECTED...IND...OH...ERN KY

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 191815Z - 192015Z



SEVERE STORM POTENTIAL APPEARS TO BE INCREASING OVER PORTIONS OF WRN
IND...NERN KY AND SRN OH. A NEW WATCH MAY BE NEEDED FOR THESE AREAS
IF ACTIVITY CONTINUES TO STRENGTHEN.

PERSISTENT UPDRAFT ACROSS PARKE COUNTY IN WCNTRL IND HAS BEEN
ANCHORED ALONG STRONG WARM FRONT/OUTFLOW BOUNDARY. WITH STRONG
INSTABILITY BUILDING TO THE WEST OF THIS AREA AS INDICATED ON 18Z
ILX RAOB...STORMS SHOULD CONTINUE TO INTENSIFY ALONG THE WARM FRONT
THROUGH THIS AFTERNOON. INCREASING MID LEVEL FLOW AND ASCENT WITHIN
EXIT REGION OF MID LEVEL JET STREAK WILL SUPPORT INTENSIFYING DEEP
LAYER SHEAR ACROSS THE REGION. LOW LEVEL SHEAR AND SEWD PROPAGATION
OF CELLS ALONG THE WARM FRONT MAY FURTHER SUPPORT STORM
ROTATION/PERSISTENCE.

ADDITIONAL STORMS HAVE RECENTLY INCREASED ON AND NORTH OF THE
BOUNDARY OVER NERN KY AND SWRN OH. WHILE THIS CONVECTION IS FARTHER
REMOVED FROM FEED OF STRONG INSTABILITY...DIURNAL TRENDS
WOULD SUPPORT A GRADUAL INCREASE IN INTENSITY.

THE AREA ON AND NORTH OF THE OH RIVER WILL CONTINUE TO BE MONITORED
FOR A WATCH IN THE NEXT HOUR OR SO.

[CaptinCrunch]

MESOSCALE DISCUSSION 0913
NWS STORM PREDICTION CENTER NORMAN OK
0144 PM CDT THU MAY 19 2005

AREAS AFFECTED...WRN/CNTRL PORTIONS OF VA/NC/SC INTO NE GA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 191844Z - 192015Z



TSTMS WILL CONTINUE TO EVOLVE AND SPREAD E/SE THROUGH THE PIEDMONT
REGION OF VA/NC/SC...WITH THREAT FOR ISOLD SEVERE WIND/HAIL
REMAINDER OF THE AFTERNOON. SEVERE WATCH NOT ANTICIPATED.

VIS IMAGERY/VOLUMETRIC RADAR DATA DEPICTS TSTM CLUSTERS EVOLVING
E/SE INVOF OF HIGHER TERRAIN IN LEE OF APPALACHIANS...WITH
ADDITIONAL DEVELOPMENT ALONG THE PIEDMONT CORRIDOR. WITH DOWNSTREAM
AIRMASS HAVING ALREADY WARMED IN THE LOWER 80S...MODERATE
INSTABILITY EXISTS WITH SBCAPES IN EXCESS OF 1000-1500 J/KG. RUC
POINT SOUNDINGS/LOCAL VADS SUGGEST 0-6 KM BULK SHEAR RANGING FROM
AROUND 30 KTS ACROSS VA...DIMINISHING TO 20-25 KTS INTO NC/SC. IN
ADDITION TO ISOLD LARGE HAIL THREAT GIVEN INSTABILITY...STEEP LOW
LEVEL LAPSE RATES/WELL MIXED BOUNDARY LAYER WILL CONTRIBUTE TO
STRONG WIND GUST POTENTIAL. EXPECTED LIMITED ORGANIZATION/MARGINAL
NATURE OF THREAT WILL LIKELY PRECLUDE SEVERE WATCH ISSUANCE.

[CaptinCrunch]

MESOSCALE DISCUSSION 0914
NWS STORM PREDICTION CENTER NORMAN OK
0326 PM CDT THU MAY 19 2005

AREAS AFFECTED...SRN INDIANA

CONCERNING...TORNADO WATCH 291...

VALID 192026Z - 192200Z

http://www.spc.noaa.gov/products/md/mcd0914.gif

ENVIRONMENT ACROSS SRN INDIANA REMAINS VERY FAVORABLE FOR STORM
ROTATION WITH PERSISTENT SUPERCELL CONTINUING TO TRACK ESEWD ALONG
STRONG WARM FRONT SITUATED ACROSS JOHNSON COUNTY. ADDITIONAL CELLS
HAVE INCREASED FROM MARTIN AND LAWRENCE COUNTIES TO BROWN COUNTY.
CELL MERGERS ARE LIKELY TO INCREASE ACROSS BROWN AND JOHNSON
COUNTIES SHORTLY. THIS ACTIVITY WILL THEN SPREAD INTO BARTHOLOMEW
COUNTY. THIS VIGOROUS CONVECTION...OCCURRING WITHIN AN ENVIRONMENT
WITH INCREASING LARGE SCALE ASCENT AND SHEAR...WILL CONTINUE TO POSE
A SEVERE HAIL/WIND/TORNADO THREAT...IN ADDITION TO VERY HEAVY RAIN.

[CaptinCrunch]

MESOSCALE DISCUSSION 0914
NWS STORM PREDICTION CENTER NORMAN OK
0326 PM CDT THU MAY 19 2005

AREAS AFFECTED...SRN INDIANA

CONCERNING...TORNADO WATCH 291...

VALID 192026Z - 192200Z



ENVIRONMENT ACROSS SRN INDIANA REMAINS VERY FAVORABLE FOR STORM
ROTATION WITH PERSISTENT SUPERCELL CONTINUING TO TRACK ESEWD ALONG
STRONG WARM FRONT SITUATED ACROSS JOHNSON COUNTY. ADDITIONAL CELLS
HAVE INCREASED FROM MARTIN AND LAWRENCE COUNTIES TO BROWN COUNTY.
CELL MERGERS ARE LIKELY TO INCREASE ACROSS BROWN AND JOHNSON
COUNTIES SHORTLY. THIS ACTIVITY WILL THEN SPREAD INTO BARTHOLOMEW
COUNTY. THIS VIGOROUS CONVECTION...OCCURRING WITHIN AN ENVIRONMENT
WITH INCREASING LARGE SCALE ASCENT AND SHEAR...WILL CONTINUE TO POSE
A SEVERE HAIL/WIND/TORNADO THREAT...IN ADDITION TO VERY HEAVY RAIN.

[CaptinCrunch]

MESOSCALE DISCUSSION 0915
NWS STORM PREDICTION CENTER NORMAN OK
0336 PM CDT THU MAY 19 2005

AREAS AFFECTED...SRN AND SERN IL...SERN MO...NERN AR...EXTREME WRN
KY

CONCERNING...SEVERE THUNDERSTORM WATCH 288...

VALID 192036Z - 192200Z



WIDELY SCATTERED STRONG TO SEVERE TSTMS HAVE BEEN GRADUALLY
INCREASING IN WATCH 288 OVER THE PAST HOUR. MOST INTENSE STORMS WERE
CURRENTLY SITUATED ALONG A WEAKLY CONVERGENT AND ILL-DEFINED LOW
LEVEL TROUGH AXIS FROM ECNTRL IL SWWD INTO SERN MO. INSTABILITY
WITHIN THIS ZONE WAS VERY STRONG AND SHOULD CONTINUE TO FUEL
VIGOROUS STORM UPDRAFTS. DEEP LAYER SHEAR AND LARGE SCALE ASCENT
ACROSS THE REGION ARE LIKELY TO REMAIN SOMEWHAT MARGINAL FOR MORE
WIDESPREAD ORGANIZED STORMS. HOWEVER...ISOLATED SUPERCELLS IN THIS
ENVIRONMENT WILL STILL BE CAPABLE OF PRODUCING LARGE HAIL AND HIGH
WINDS...ESPECIALLY OVER THE NEXT COUPLE OF HOURS.

[CaptinCrunch]

MESOSCALE DISCUSSION 0916
NWS STORM PREDICTION CENTER NORMAN OK
0341 PM CDT THU MAY 19 2005

AREAS AFFECTED...SRN IND...WRN AND MIDDLE TN...KY

CONCERNING...SEVERE THUNDERSTORM WATCH 289...

VALID 192041Z - 192145Z



STORM CLUSTERS ALONG THE ERN EDGE OF SEVERE TSTM WATCH 289 SHOULD
CONTINUE TO MOVE EAST THROUGH EARLY EVENING. INSTABILITY SHOULD
SUPPORT SEVERE HAIL AND ISOLATED DOWNBURST WINDS WITH THIS ACTIVITY
AND A NEW WATCH MAY BE ISSUED SHORTLY.

[CaptinCrunch]

MESOSCALE DISCUSSION 0917
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT THU MAY 19 2005

AREAS AFFECTED...FAR ERN IA/NRN IL/SRN WI INTO NRN IND

CONCERNING...SEVERE THUNDERSTORM WATCH 290...

VALID 192050Z - 192215Z



WW 290 CONTINUES ACROSS FAR ERN IA/NRN IL/FAR SRN WI UNTIL 02Z. WILL
CONTINUE TO MONITOR TRENDS FOR AN ADDITIONAL SEVERE WATCH INTO NRN
IN. ISOLD SEVERE THREAT TO ALSO PERSIST ACROSS SRN WI NORTH OF WW
290.

SEVERE THREAT REMAINS ACROSS MUCH OF WW 290 IN SHORT TERM...WITH
MODERATE INSTABILITY REMAINING AS PRIMARY CLUSTER OF TSTMS MOVES
SEWD ALONG I-88 CORRIDOR. FURTHER EAST...SATELLITE TRENDS OVER PAST
HALF HOUR FEATURE DEEPENING CU FIELD WITH ONGOING DESTABILIZATION
ACROSS NW IND...WHERE WARM FRONT APPEARS TO WORKING NEWD 1) AHEAD OF
UPPER MISSISSIPPI VALLEY UPPER TROUGH AND 2) AROUND PERIPHERY OF
CNTRL IND ONGOING CONVECTION. ADDITIONAL WATCH MAY BE NEEDED GIVEN
DESTABILIZATION/INCREASING DYNAMIC ASCENT AND/OR POTENTIAL FOR NRN
IL TSTMS TO PROPAGATE INTO NRN IN.

ACROSS SRN WI...ISOLD SEVERE THREAT TO PERSIST OVER NEXT FEW HOURS
OWING TO MARGINALLY UNSTABLE ATMOSPHERE ALONG FRONTAL OCCLUSION. IN
ADDITION TO ISOLD LARGE HAIL/STRONG WIND GUSTS...ENHANCED STRETCHING
INVOF FRONTAL OCCLUSION/REGION OF 100 J/KG 0-3 KM CAPE MAY CONTINUE
TO YIELD THREAT FOR ISOLD/BRIEF TORNADOES THROUGH LATE AFTERNOON.

[CaptinCrunch]

MESOSCALE DISCUSSION 0928
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT FRI MAY 20 2005

AREAS AFFECTED...SRN TN/NERN AL INTO NRN GA AND NRN SC

CONCERNING...SEVERE THUNDERSTORM WATCH 298...299...

VALID 201242Z - 201415Z



THROUGH 14-15Z...GREATEST SEVERE WEATHER THREAT WILL EXIST ACROSS
SRN MIDDLE TN/NERN AL INTO NWRN GA.

LINE OF TSTMS HAS RE-INTENSIFIED OVER THE PAST HOUR OVER MIDDLE TN
INTO N-CNTRL AL...WITH LEADING EDGE OF MOST INTENSE ACTIVITY FROM
MARION COUNTY TN SWWD INTO LIMESTONE COUNTY IN N-CNTRL AL. BOTH 12Z
BMX AND FFC SOUNDINGS INDICATE THE PRESENCE OF MODERATE INSTABILITY
/I.E. MUCAPES OF 1000-1500 J/KG/ ATOP A NOCTURNAL SURFACE INVERSION.
BREAKS IN CLOUDS ACROSS DOWNSTREAM AIR MASS /PER MORNING VISIBLE
IMAGERY/ SUGGEST THAT DIABATIC HEATING SHOULD ELIMINATE THIS
INVERSION BY MID TO LATE MORNING WITH STORMS BECOMING MORE
SURFACE-BASED WITH TIME. GIVEN ANTICIPATED INCREASE IN MID AND
HIGH-LEVEL WINDS WITH APPROACH OF OH VALLEY SHORTWAVE
TROUGH...CORRIDOR FROM CURRENT ACTIVITY SEWD ACROSS NRN GA WILL
BECOME INCREASINGLY SUPPORTIVE OF SEVERE STORMS CAPABLE OF DAMAGING
WINDS AND LARGE HAIL. ADDITIONAL BACKBUILDING DEVELOPMENT MAY OCCUR
OVER THE COURSE OF THE MORNING ACROSS NRN INTO CNTRL AL...POSSIBLY
REQUIRING THE ISSUANCE OF AN ADDITIONAL WW.

FARTHER TO THE E OVER NRN SC INTO WRN/CNTRL NC...AIR MASS IS MUCH
MORE STABLE AND WW 298 WILL BE ALLOWED TO EXPIRE AT 13Z.

[CaptinCrunch]

MESOSCALE DISCUSSION 0930
NWS STORM PREDICTION CENTER NORMAN OK
1255 PM CDT FRI MAY 20 2005

AREAS AFFECTED...PORTIONS OF THE TN VALLEY INTO MUCH OF MS/AL/GA

CONCERNING...SEVERE THUNDERSTORM WATCH 300...

VALID 201755Z - 201900Z



NEW WW/S ARE BEING CONSIDERED FOR MUCH OF NRN/CENTRAL MS AND EWD
ACROSS CENTRAL AL. ONGOING THREAT FOR DAMAGING WINDS AND HAIL WILL
CONTINUE ACROSS WW 300 WITH ADDITIONAL STORMS DEVELOPING AND MOVING
SEWD FROM SRN MIDDLE TN TO NRN/CENTRAL GA.

18Z SURFACE ANALYSIS INDICATED A PRIMARY LOW OVER MIDDLE TN ALONG
THE SYNOPTIC BOUNDARY...WITH SEVERAL SURFACE TROUGHS EXTENDING SWD
AND WSWWD FROM THIS LOW INTO CENTRAL AL/SRN MS AND ACROSS NRN
PORTIONS OF NRN AL/MS INTO AR. AIR MASS ALONG AND SOUTH OF THESE
TROUGHS HAS BECOME MODERATELY UNSTABLE WITH MLCAPE VALUES UP TO 2000
J/KG.

***POTENTIAL WW/S NRN/CENTRAL MS INTO CENTRAL AL***
VIS/RADAR IMAGERY SHOW THUNDERSTORMS DEVELOPING ALONG SURFACE
TROUGHS INTO NRN AL/MS AND INTO CENTRAL AL/SERN MS. DEEP LAYER
SHEAR WILL CONTINUE TO INCREASE SWD ACROSS MS/AL WITH 35-45 KT OF
SFC-6 KM SHEAR SUPPORTIVE OF SUPERCELLS WITHIN MODERATELY UNSTABLE
AIRMASS. HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREATS.

***WW 300***
REGIONAL RADARS SHOW SEVERAL LINE OF STORMS WITHIN WW 300 MOVING TO
THE SE ALONG THE INSTABILITY GRADIENT AND WITHIN NWLY FLOW ALOFT.
LARGE SCALE ASCENT IN ADVANCE OF THE SHORT WAVE TROUGH OVER CENTRAL
KY INTO NRN AL AND CONVERGENCE ALONG SURFACE TROUGHS AND OUTFLOW
BOUNDARIES WILL CONTINUE TO SUPPORT A THREAT FOR SEVERE STORMS
ACROSS ALL OF WW 300.

[CaptinCrunch]

MESOSCALE DISCUSSION 0931
NWS STORM PREDICTION CENTER NORMAN OK
0139 PM CDT FRI MAY 20 2005

AREAS AFFECTED...ERN ND AND NWRN MN

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 201839Z - 202045Z



ISOLATED SVR STORMS MAY DEVELOP OVER ERN ND INTO FAR NWRN MN BETWEEN
20-22Z.

SFC ANALYSIS SHOWS A TROUGH EXTENDING FROM ERN CAVALIER COUNTY SWWD
INTO KIDDER COUNTY. SATELLITE AND RADAR IMAGERY SHOWS ACCAS
OVERSPREADING THE AREA. AS SFC CONTINUES TO DESTABILIZE...FORECAST
SOUNDINGS SUGGEST THAT THIS CONVECTION SHOULD BECOME ROOTED IN THE
BOUNDARY LAYER OVER ERN ND/FAR NWRN MN WITHIN THE NEXT 1-2 HOURS AS
LOW LEVELS WARM INTO THE MID 80S...AND DEWPTS REMAIN OR MIX INTO THE
50S. STEEP MID LEVEL LAPSE RATES AROUND 7.5 DEG C/KM AND MODERATE
CLOUD LAYER SHEAR OF AROUND 40 KTS WILL COMBINE WITH MUCAPES AROUND
1500 J/KG TO AID IN THE THREAT FOR ISOLATED LARGE HAIL/DAMAGING
WINDS ALONG THE INSTABILITY AXIS. LACK OF STRONGER CONVERGENCE ALONG
THE SFC TROUGH AND MID LEVEL RIDGING/SLIGHT WARMING MAY BE A
LIMITING FACTOR FOR GREATER COVERAGE OF SVR STORMS AND THE NEED FOR
A WW. TRENDS WILL CONTINUE TO BE MONITORED FOR A POSSIBLE WW IN THE
NEXT FEW HOURS.

[CaptinCrunch]

MESOSCALE DISCUSSION 0932
NWS STORM PREDICTION CENTER NORMAN OK
0143 PM CDT FRI MAY 20 2005

AREAS AFFECTED...PORTIONS OF ERN GA AND SRN SC

CONCERNING...SEVERE THUNDERSTORM WATCH 301...

VALID 201843Z - 201945Z



THREAT FOR DAMAGING WINDS AND HAIL WILL CONTINUE THIS AFTERNOON
ACROSS WW 301. THROUGH 20Z...GREATEST THREAT FOR DAMAGING WINDS
WILL BE ACROSS NRN PORTIONS OF WW 301...EAST OF A LINE FROM
EDGEFIELD COUNTY SC TO RICHMOND COUNTY GA.

REGIONAL RADARS INDICATED A WELL DEFINED BOW ECHO EXTENDING FROM
EDGEFIELD COUNTY SC TO RICHMOND COUNTY GA. AIR MASS DOWNSTREAM
REMAINS MODERATELY UNSTABLE WITH MLCAPE VALUES UP TO 1500-2000
J/KG...SUPPORTING A CONTINUED EWD MOVEMENT OF THE BOW AT 40-45 KT.
ORIENTATION OF INSTABILITY GRADIENT E-W ACROSS SRN SC...SUGGESTS
THIS WILL BE THE ZONE FOR GREATEST THREAT FOR DAMAGING WINDS THROUGH
20Z. DEEP LAYER SHEAR IS STRONGER OVER NRN PORTIONS OF WW 301 WHICH
SHOULD ENABLE THE BOW STRUCTURE TO REMAIN ORGANIZED.

ELSEWHERE...THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER CENTRAL
PORTIONS OF THE WATCH WITHIN AXIS OF STRONGEST INSTABILITY...AND
ALSO ALONG THE WWD MOVING COASTAL BOUNDARY IN THE ERN PORTIONS OF WW
301.

[CaptinCrunch]

MESOSCALE DISCUSSION 0973
NWS STORM PREDICTION CENTER NORMAN OK
0412 PM CDT MON MAY 23 2005

AREAS AFFECTED...CENTRAL/ERN VA

CONCERNING...SEVERE THUNDERSTORM WATCH 314...

VALID 232112Z - 232245Z



SVR THREAT CONTINUES OVER ALL OF WW 314 FOR THE NEXT FEW HOURS.

ISOLATED SUPERCELL WILL MOVE SEWD AROUND 30 KTS THROUGH SERN VA
TOWARDS NORFOLK/NEWPORT NEWS IN THE 1-1.5 HOURS. INTERACTION OF
SUPERCELL WITH OCEAN BREEZE FRONT AND ENHANCED LOW LEVEL SHEAR /27
KTS OF 0-1 KM SHEAR PER WAKEFIELD VWP/ MAY AID IN A SHORT TERM
TORNADO THREAT OVER SURRY AND ISLE OF WRIGHT COUNTIES THROUGH 22Z
BEFORE THE SUPERCELL CROSSES INTO MORE STABLE AIR LOCATED OVER
NEWPORT NEWS/NORFOLK AREA.

FARTHER WEST...DESPITE EARLIER PRECIP...SUFFICIENT CLEARING HAS
TAKEN PLACE TO AID IN DESTABILIZATION AGAIN OVER CENTRAL VA.
ISOLATED SVR STORMS OVER WV AHEAD OF WELL DEFINED VORT MAX ARE
LIKELY TO MAINTAIN THEIR INTENSITY OR INCREASE AS THEY MOVE INTO
WCENTRAL VA AND WW 314.

[CaptinCrunch]

MESOSCALE DISCUSSION 0975
NWS STORM PREDICTION CENTER NORMAN OK
0439 PM CDT MON MAY 23 2005

AREAS AFFECTED...NERN NM...WRN TX AND OK PANHANDLES

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 232139Z - 232315Z



CONVECTION DEVELOPING ALONG THE RATON MESA/FRONT RANGE OF NERN NM
SHOULD CONTINUE TO MOVE SLOWLY OFF THE HIGHER TERRAIN OVER THE NEXT
FEW HOURS. IF INCREASING TRENDS CAN CONTINUE AND THREAT BECOMES MORE
THAN ISOLATED...A WW MAY BE NEEDED BEFORE 00Z.

LATEST OBJECTIVE ANALYSIS INDICATES THAT AROUND 1000 J/KG OF MLCAPE
WITH NO MLCINH EXISTS OVER THE HIGHER TERRAIN OF NERN NM. MODERATE
LOW LEVEL ELY FLOW OF 10-15 KTS BENEATH MID LEVEL WLY FLOW OF 30 KTS
/OR EFFECTIVE SHEAR AROUND 40 KTS/ IS SUFFICIENT FOR SUPERCELL TYPE
STORMS. SELY LOW LEVEL STORM RELATIVE INFLOW AROUND 20 KTS SHOULD
SUPPORT CONVECTION MOVING OFF INTO LOWER TERRAIN GRADUALLY...SINCE
MLCINH OVER THE NWRN TX PANHANDLE/WRN OK PANHANDLE REMAINS AOB 50
J/KG. IF CONVECTION CAN BECOME MORE ORGANIZED OVER THE NEXT FEW
HOURS...GREATER INSTABILITY OVER THE WRN TX PANHANDLE/WRN OK
PANHANDLE SUGGESTS THAT SVR THREAT MAY INCREASE IN THESE AREAS. THIS
AREA WILL CONTINUED TO BE MONITORED FOR A POSSIBLE WW. LARGE HAIL
AND DAMAGING WINDS ARE THE PRIMARY THREATS...SINCE RELATIVELY HIGH
LCL HEIGHTS EXIST OVER THE AREA.

[CaptinCrunch]

MESOSCALE DISCUSSION 0983
NWS STORM PREDICTION CENTER NORMAN OK
0913 AM CDT TUE MAY 24 2005

AREAS AFFECTED...EXTREME SERN KS...EXTREME NERN OK...EXTREME SWRN MO
AND WRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 319...

VALID 241413Z - 241445Z



REMAINING PORTIONS OF SEVERE TSTM WATCH 319 EXPIRES AT 15Z AND WILL
NOT BE EXTENDED/REISSUED.

MCS CONTINUES TO DECAY WITH STRONGEST TSTMS MOVING INTO SWRN MO AT
MID-MORNING. THESE STORMS ARE JUST DOWNSTREAM OF A MCV AND ON THE
NOSE OF THE SWLY 15-20 KT LLJ. LLJ IS EXPECTED TO CONTINUE A
DIURNAL WEAKENING TREND AND THE TSTMS SHOULD DIMINISH THROUGH LATE
MORNING.

LATER THIS AFTERNOON...TSTMS MAY DEVELOP ALONG REMNANT OUTFLOW
BOUNDARIES/AHEAD OF MCV ACROSS THE REGION. STRONGER TSTMS MAY HAVE
A PROPENSITY TO DEVELOP NEAR/S OF THE WEAK SYNOPTIC BOUNDARY
SITUATED SEWD FROM MCV CENTER TO NEAR FORT SMITH TO SRN AR.

[CaptinCrunch]

MESOSCALE DISCUSSION 0987
NWS STORM PREDICTION CENTER NORMAN OK
0103 PM CDT TUE MAY 24 2005

AREAS AFFECTED...ERN CO...EXTREME SWRN NEB AND EXTREME NWRN KS

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 241803Z - 242000Z



TSTMS SHOULD CONTINUE TO GROW UPSCALE OFF THE FRONT RANGE THIS AFTN
WITH THE RISK OF SUPERCELLS WITH VERY LARGE HAIL AND DAMAGING WINDS.
ISOLD TORNADOES WILL BE POSSIBLE. WW WILL LIKELY BE NEEDED BEFORE
20Z.

17Z MESOANALYSIS PLACES A WEAK E-W BOUNDARY FROM A LOW VCNTY KDEN TO
SWRN NEB...AUGMENTED BY ELEVATED MORNING TSTMS/ACCAS. TO THE S OF
THE BOUNDARY...THE WEAK LOW-LEVEL FLOW HAS TURNED UPSLOPE OWING TO
HEATING AND RESPONSE TO WEAK HEIGHT FALLS SPREADING EWD FROM
UPSTREAM MID-LEVEL WAVE. THE FLOW IS MAINTAINING UPPER 40S TO NEAR
50 BOUNDARY LAYER DEW POINTS TO THE FRONT RANGE.

CONTINUED HEATING WILL START TO ERASE CINH ON THE ADJACENT PLAINS
ABOUT 20Z. CURRENT CONVECTIVE PULSES ALONG THE FRONT RANGE WILL
EVENTUALLY ROOT INTO THE UNSTABLE BOUNDARY LAYER FARTHER EAST AND
RESULT IN RAPID TSTM DEVELOPMENT. OTHER STORMS WILL PROBABLY FORM
EWD ALONG THE WEAK BOUNDARY TOWARD SWRN NEB/NWRN KS LATER THIS AFTN.


THOUGH VERTICAL SHEAR THROUGH 6KM IS SOMEWHAT WEAK FOR SUPERCELLS AT
MIDDAY...ENHANCED MID-LEVEL FLOW ASSOCIATED WITH THE APPROACHING
SHORTWAVE TROUGH WILL RESULT IN INCREASING DEEP LAYER SHEAR LATER
THIS AFTN. AS A RESULT...SUPERCELLS WILL BE LIKELY. MAGNITUDE OF
LAPSE RATES WILL SUPPORT VERY LARGE HAIL ALONG WITH A DAMAGING WIND
THREAT. ALSO...THOUGH DEW POINT DEPRESSION ARE HIGH...PRESENCE OF A
DENVER CYCLONE AND E-W SHEAR ZONE/BOUNDARY... LANDSPOUTS/TORNADOES
WILL BE POSSIBLE...PARTICULARLY IN THE ZONE FROM JUST E OF KDEN TO
WASHINGTON COUNTY CO.